Precise Prediction for the Mass of the Lightest Higgs Boson in the MSSM
a r X i v :h e p -p h /9807423v 2 1 S e p 1998
KA–TP–13–1998hep-ph/9807423
Precise Prediction for the Mass of the Lightest Higgs Boson in the MSSM
S.Heinemeyer,W.Hollik and G.Weiglein
Institut f¨u r Theoretische Physik,Universit¨a t Karlsruhe,
D–76128Karlsruhe,Germany
Abstract
The leading diagrammatic two-loop corrections are incorporated into the prediction for the mass of the lightest Higgs boson,m h ,in the Minimal Supersymmetric Standard Model (MSSM).The results,containing the complete diagrammatic one-loop correc-tions,the new two-loop result and re?nement terms incorporating leading electroweak two-loop and higher-order QCD contributions,are discussed and compared with results obtained by renormalization group calculations.Good agreement is found in the case of vanishing mixing in the scalar quark sector,while sizable deviations occur if squark mixing is taken into account.
The search for the lightest Higgs boson provides a direct and very stringent test of Supersymmetry(SUSY),since the prediction of a relatively light Higgs boson is common to all Supersymmetric models whose couplings remain in the perturbative regime up to a very high energy scale[1].A precise prediction for the mass of the lightest Higgs boson in terms of the relevant SUSY parameters is crucial in order to determine the discovery and exclusion potential of LEP2and the upgraded Tevatron and also for physics at the LHC, where eventually a high-precision measurement of the mass of this particle might be possible.
In the Minimal Supersymmetric Standard Model(MSSM)[2]the mass of the lightest Higgs boson,m h,is restricted at the tree level to be smaller than the Z-boson mass.This bound,however,is strongly a?ected by the inclusion of radiative corrections.The dom-inant one-loop corrections arise form the top and scalar-top sector via terms of the form
G F m4t ln(m?t
1m?t
2
/m2t)[3].They increase the predicted values of m h and yield an upper bound
of about150GeV.These results have been improved by performing a complete one-loop calculation in the on-shell scheme,which takes into account the contributions of all sectors of the MSSM[4,5,6].Beyond one-loop order renormalization group(RG)methods have been applied in order to obtain leading logarithmic higher-order contributions[7,8,9,10], and a diagrammatic calculation of the dominant two-loop contributions in the limiting case of vanishing?t-mixing and in?nitely large M A and tanβhas been carried out[11].
The results of the latter calculations were found to yield considerably lower values for m h than the one-loop on-shell calculation.The results obtained within the RG approach di?er by up to20GeV from the one-loop on-shell result.The bulk of this di?erence can be attributed to the higher-order leading logarithmic contributions which are included in the RG results.The one-loop result on the other hand contains non-leading contributions which are not included in the RG results and whose size has not yet been precisely determined. Due to the large di?erence between the complete one-loop on-shell calculation and the RG results,and due to the di?culty in comparing the results of the two approaches,it is not easy to give an estimate for the accuracy of the current theoretical prediction for m h in a similar way as done,for instance,for the electroweak precision observables within the Standard Model(SM)(see Ref.[12]).
Recently a Feynman-diagrammatic calculation of the leading two-loop corrections of O(ααs)to the masses of the neutral CP-even Higgs bosons has been performed[13].Com-pared to the leading one-loop result the two-loop contribution was found to give rise to a considerable reduction of the m h value.
It is the purpose of this letter to combine the full diagrammatic one-loop on-shell result[5] with the leading diagrammatic two-loop result[13],and to obtain in this way the currently most precise prediction for m h within the Feynman-diagrammatic approach for arbitrary values of the parameters of the Higgs and scalar top sector of the MSSM.Further re?nements concerning the leading two-loop Yukawa corrections of O(G2F m6t)[8,14]and of leading QCD corrections beyond two-loop order are included.The resulting predictions for m h are discussed in view of the discovery potential of LEP2[15]and are compared with the results obtained using the RG approach[8,9,10].
Contrary to the SM,in the MSSM two Higgs doublets are needed.The Higgs potential
1
is given by [16]
V
=m 21H 1ˉH 1+m 22H 2ˉH 2?m 212(?ab H a 1H b 2+h.c.)
+g ′2+g 2
2
|H 1ˉH 2|2,(1)
where m 1,m 2,m 12are soft SUSY-breaking terms,g,g ′are the SU (2)and U (1)gauge cou-plings,and ?12=?1.
The doublet ?elds H 1and H 2are decomposed in the following way:
H 1= H 11H 2
1
= v 1+(φ01+iχ01)/
√2
.(2)
The potential eq.(1)can be described with the help of two independent parameters (besides
g ,g ′):tan β=v 2/v 1and M 2
A =?m 212(tan β+cot β),where M A is the mass of the CP -odd A boson.
In order to obtain the CP -even neutral mass eigenstates,the rotation
H 0
h 0
=
cos αsin α
?sin α
cos α
φ01φ02
(3)
is performed,where the mixing angle αis given in terms of tan βand M A by
tan 2α=tan 2β
M 2A +M 2Z
2
<α<0.
(4)
At tree level the mass matrix of the neutral CP -even Higgs bosons is given in the φ1?φ2
basis in terms of M Z and M A by
M 2,tree
Higgs
=
m 2φ1
m 2φ1φ2
m 2φ1φ2
m 2φ2
=
M 2A
sin 2
β+M 2Z
cos 2
β?(M 2A +M 2
Z )sin βcos β?(M 2A +M 2
Z )sin βcos β
M 2A cos 2β+M 2Z sin 2β
,(5)
which then has to be rotated with the angle αaccording to eq.(3),and one obtains the
tree-level Higgs-boson masses
M 2,tree
Higgs
α
?→
m 2H,tree
00
m 2h,tree
.(6)
In the Feynman-diagrammatic approach the one-loop corrected Higgs masses are derived
by ?nding the poles of the h ?H -propagator matrix whose inverse is given by
(?Higgs )?1=?i
q 2
?
m 2H,tree
+?ΣH (q 2)?ΣhH (q 2)?ΣhH (q 2)q 2?m 2h,tree +?Σh (q 2)
,(7)
2
where the ?Σ
denote the full one-loop contributions to the renormalized Higgs-boson self-energies.For these self-energies we take the result of the complete one-loop on-shell calcu-lation of Ref.[5].The agreement with the result obtained in Ref.[4]is better than 1GeV for almost the whole MSSM parameter space.
As mentioned above the dominant contribution arises from the t ??t
-sector.The current eigenstates of the scalar quarks,?q L and ?q R ,mix to give the mass eigenstates ?q 1and ?q 2.The non-diagonal entry in the scalar quark mass matrix is proportional to the mass of the quark
and reads for the ?t
-mass matrix m t M LR t =m t (A t ?μcot β),
(8)
where we have adopted the conventions used in Ref.[17].Due to the large value of m t
mixing e?ects have to be taken into account.Diagonalizing the ?t
-mass matrix one obtains the eigenvalues m ?t 1and m ?t 2and the ?t mixing angle θ?t .
The leading two-loop corrections have been obtained in Ref.[13]by calculating the
O (ααs )contribution of the t ??t
-sector to the renormalized Higgs-boson self-energies at zero external momentum from the Yukawa part of the theory.Since this calculation was performed in the φ1?φ2-basis,we perform the rotation into the h ?H -basis according to eq.(3):
?Σ(2)H =cos 2α?Σ(2)φ1+sin 2α?Σ(2)φ2+2sin αcos α?Σ(2)φ1φ2?Σ(2)h =sin 2α?Σ(2)φ1+cos 2α?Σ(2)φ2?2sin αcos α?Σ(2)φ1φ2
?Σ(2)hH =?sin αcos α ?Σ(2)φ1??Σ(2)φ2
+(cos 2α?sin 2α)?Σ(2)φ1φ2
.(9)
At the two-loop level the matrix (7)then consists of the renormalized Higgs-boson self-energies
?Σs (q 2)=?Σ(1)s (q 2)+?Σ(2)s (0),s =h,H,hH,(10)where the momentum dependence is neglected only in the two-loop contribution.The Higgs-boson masses at the two-loop level are obtained by determining the poles of the matrix ?Higgs
in eq.(7).
We have implemented two further steps of re?nement into the prediction for m h ,which are
shown separately in the plots below.The leading two-loop Yukawa correction of O (G 2F m 6
t )is taken over from the result obtained by renormalization group methods.It reads [8,14]
?m 2h =
9
4m 2t
sin 22θ?
t 2
2?
m 2?t
2+m 2
?t 1m 2?t
1
+m 2?t 2?m 2
?t
1m 2?t
1
,(12)t =
1
m 4t
.(13)
3
The second step of re?nement concerns leading QCD corrections beyond two-loop order, taken into account by using the m t=
m t in the?t mass matrix for the two-loop result,since in the RG results the running masses appear everywhere.This three-loop e?ect gives rise to a shift up to1.5GeV in the prediction for m h.
For the numerical evaluation we have chosen two values for tanβwhich are favored by SUSY-GUT scenarios[18]:tanβ=1.6for the SU(5)scenario and tanβ=40for the SO(10)scenario.Other parameters are M Z=91.187GeV,M W=80.375GeV,G F= 1.1663910?5GeV?2,αs(m t)=0.1095,and m t=175GeV.For the?gures below we have furthermore chosen M=400GeV(M is the soft SUSY breaking parameter in the chargino and neutralino sector),M A=500GeV,and m?g=500GeV as typical values(if not indicated di?erently).The scalar top masses and the mixing angle are derived from the parameters
M?t
L ,M?t
R
and M LR
t
of the?t mass matrix(our conventions are the same as in Ref.[17]).In
the?gures below we have chosen m?q≡M?t L=M?t R.
The plot in Fig.1shows the result for m h obtained from the diagrammatic calculation of the full one-loop and leading two-loop contributions.The two steps of re?nement dis-cussed above are shown in separate curves.For comparison the pure one-loop result is also
given.The results are plotted as a function of M LR
t /m?q,where m?q is?xed to500GeV.
The qualitative behavior is the same as in Ref.[13],where the result containing only the leading one-loop contribution(and without further re?nements)was shown.The two-loop contributions give rise to a large reduction of the one-loop result of10–20GeV.The two
steps of re?nement both increase m h by up to2GeV.A minimum occurs for M LR
t =0GeV
which we refer to as‘no mixing’.A maximum in the two-loop result for m h is reached for
about M LR
t /m?q≈2in the tanβ=1.6scenario as well as in the tanβ=40scenario.This
case we refer to as‘maximal mixing’.The maximum is shifted compared to its one-loop
value of about M LR
t /m?q≈2.4.The two steps of re?nement have only a negligible e?ect on
the location of the maximum.
In Fig.2m h is shown in the two scenarios with tanβ=1.6and tanβ=40as a function of m?q for no mixing and maximal mixing.The tree-level,the one-loop and the two-loop results with the two steps of re?nement are shown(the values of m?q are such that the corresponding?t-masses lie within the experimentally allowed region).In all scenarios of Fig.2the two-loop corrections give rise to a large reduction of the one-loop value of m h.The biggest e?ect occurs for the tanβ=1.6scenario with maximal mixing.The inclusion of the re?nement terms leads to a slight shift in m h towards higher values,whose size is about 20%of the two-loop correction.In the tanβ=1.6scenario,m h reaches about80GeV for m?q=1TeV in the no-mixing case,and about100GeV for m?q=1TeV in the maximal-mixing case.For tanβ=40the respective values of m h are nearly115GeV in the no-mixing case,and almost130GeV in the maximal-mixing case.
Varying the gaugino parameter M,which enters via the non-leading one-loop contribu-tions,in the results of Fig.2changes the value of m h within3GeV.Di?erent values of the gluino mass,m?g,in the two-loop contribution a?ect the prediction for m h by up to3GeV.
4
0.0
0.5
1.0
1.5
2.0 2.5
3.0
M t
LR /m q ~
20406080100120
140160m h [G e V ]
1?loop 2?loop
2?loop (running m t )
2?loop (running m t ), Yukawa term incl.
m q ~ = 500 GeV, m g ~ = 500 GeV, M A = 500 GeV
M = m q
~, μ = ? m q ~tan β = 40
tan β = 1.6
Figure 1:One-and two-loop results for m h as a function of M LR t /m ?q for two values of tan β.The two steps of re?nement discussed in the text are shown separately.
Allowing for a splitting between the parameters M ?t L ,M ?t
R in the ?t mass matrix yields max-imal values of m h which are approximately the same as for the case m ?q =M ?t
L =M ?t R (see also Fig.5below).Varying tan βaround the value tan β=1.6leads to a relatively large e?ect in m h (higher values for m h are obtained for larger tan β),while the e?ect of varying tan βaround tan β=40is marginal.A more detailed analysis of the dependence of our results on the di?erent SUSY parameters will be presented in a forthcoming publication.The discovery limit of LEP2is expected to be slightly above 100GeV [15].Accordingly,our results con?rm that for the scenario with tan β=1.6practically the whole parameter space of the MSSM can be covered at LEP2.For slightly larger tan βand maximal mixing,however,some parameter space could remain in which the Higgs boson escapes detection at LEP2.For tan β=40,on the other hand,a full exploration of the MSSM parameter space will not be possible at LEP2.While the prediction for m h is at the edge of the LEP2range in the no-mixing case,the case of large mixing will be a challenge for the upgraded Tevatron or will ?nally be probed at LHC.
We now turn to the comparison of our diagrammatic results with the predictions obtained via renormalization group methods.We begin with the case of vanishing mixing in the ?t
sector and large values of M A ,for which the RG approach is most easily applicable and is expected to work most accurately.In order to study di?erent contributions separately,we have ?rst compared the diagrammatic one-loop on-shell result [5]with the one-loop leading log result (without renormalization group improvement)given in Ref.[10]and found very good agreement,typically within 1GeV.We then performed a leading log expansion of our
5
100
300
500700900
m q ~ [GeV]
020406080
100120m h [G e V ]
tree level 1?loop 2?loop
2?loop (running m t )
2?loop (running m t ), Yukawa term incl.
M A = 500 GeV, m g ~ = 500 GeV, tan β = 1.6
M = m q
~, μ = ? m q ~no mixing max. mixing
100
300
500700900
m q ~ [GeV]
20
40
6080100120
140160m h [G e V ]
tree level 1?loop 2?loop
2?loop (running m t )
2?loop (running m t ), Yukawa term incl.
M A = 500 GeV, m g ~ = 500 GeV, tan β = 40M = m q
~, μ = ? m q ~no mixing
max. mixing
Figure 2:The mass of the lightest Higgs boson for tan β=1.6and tan β=40.The
tree-level,the one-loop and the two-loop results for m h are shown as a function of m ?q for the no-mixing and the maximal-mixing case.
diagrammatic result (which corresponds to the two-loop contribution in the RG approach)and also found agreement with the full two-loop result within about 1GeV.Finally,as shown in Fig.3,we have compared our diagrammatic result for the no-mixing case including the re?nement terms with the RG results obtained in Ref.[9].1As can be seen in Fig.3,after the inclusion of the re?nement terms the diagrammatic result for the no-mixing case agrees very well with the RG result.The deviation between the results exceeds 2GeV only for tan β=1.6and m ?q <150GeV.For smaller values of M A the comparison for the no-mixing case looks qualitatively the same.For tan β=1.6and values of M A below 100GeV slightly larger deviations are possible.Since the RG results do not contain the gluino mass as a parameter,varying m ?g gives rise to an extra deviation,which in the no-mixing case does not exceed 1GeV.Varying the other parameters μand M in general does not lead to a sizable e?ect in the comparison with the corresponding RG results.
We now consider the situation when mixing in the ?t
sector is taken into account.We have again compared the full one-loop result with the one-loop leading log result used within the RG approach [10]and found good agreement.Only for values of M A below 100GeV and large mixing deviations of about 5GeV occur.In Fig.4our diagrammatic result including the re?nement terms is compared with the RG results [9]as a function of M LR t /m ?q for tan β=1.6and tan β=40.The point M LR t /m ?q =0corresponds to the plots shown in
Fig.3,except that the parameter μis now set to μ=?m ?q .For larger ?t -mixing sizable
100
300
500
700900110013001500
m q ~ [GeV]
203040506070
8090m h [G e V ]
RG
2?loop diag.
2?loop diag. (running m t )
2?loop diag. (running m t ), Yukawa term incl.
M A = 1000 GeV, m g ~ = 500 GeV, tan β = 1.6M t LR
= 0 GeV, μ = 0 GeV, M = m q ~
100
300500
700900110013001500
m q ~ [GeV]
70
80
90
100
110
120
m h [G e V ]
RG
2?loop diag.
2?loop diag. (running m t )
2?loop diag. (running m t ), Yukawa term incl.
M A = 1000 GeV, m g
~ = 500 GeV, tan β = 40M t LR
= 0 GeV, μ = 0 GeV, M = m q ~Figure 3:Comparison between the Feynman-diagrammatic calculations and the results
obtained by renormalization group methods [9].The mass of the lightest Higgs boson is shown for the two scenarios with tan β=1.6and tan β=40for the case of vanishing
mixing in the ?t
-sector.deviations between the diagrammatic and the RG results occur,which can exceed 5GeV for
moderate mixing and become very large for large values of M LR t /m ?q .As already stressed above,the maximal value for m h in the diagrammatic approach is reached for M LR t /m ?q ≈2,whereas the RG results have a maximum at M LR t /m ?q ≈2.4,i.e.at the one-loop value.Varying the value of m ?g in our result leads to a larger e?ect than in the no-mixing case and shifts the diagrammatic result relative to the RG result within ±2GeV.
The results of our diagrammatic on-shell calculation and the RG methods have been
compared above in terms of the parameters M ?t L ,M ?t
R and M LR t of the ?t mixing matrix,since the available numerical codes for the RG results [9,10]are given in terms of these parameters.However,since the two approaches rely on di?erent renormalization schemes,the meaning of these (non-observable)parameters is not precisely the same in the two approaches starting from two-loop order.Indeed we have checked that assuming ?xed values for the physical parameters m ?t 1,m ?t 2,and θ?t and deriving the corresponding values of the parameters M ?t L ,
M ?t R and M LR
t
in the on-shell scheme as well as in the
0.0
0.5 1.0
1.5
2.0 2.5
3.0
M t LR
/m q ~
406080
100
120
m h [G e V ]
RG
diag. 2?loop (running m t ), Yukawa term incl.
m q
~ = 1000 GeV, m g ~ = 500 GeV, μ = ? m q ~, M = m q ~tan β = 1.6, M A = 1000 GeV
0.0
0.5 1.0
1.5
2.0 2.5
3.0
M t
LR /m q ~
60
80
100
120
140
m h [G e V ]
RG
diag. 2?loop (running m t ), Yukawa term incl.
m q ~ = 1000 GeV, m g ~ = 500 GeV, μ = ?m q ~, M = m q ~tan β = 40, M A = 1000 GeV
Figure 4:Comparison between the Feynman-diagrammatic calculations and the results obtained by renormalization group methods [9].The mass of the lightest Higgs boson is shown for the two scenarios with tan β=1.6and tan β=40for increasing mixing in the ?t -sector and m ?q =M A .renormalization schemes we ?nd it preferable to compare predictions for physical observables in terms of other observables (instead of unphysical parameters).As a step into this direction we compare in Fig.5the diagrammatic results and the RG results as a function of the physical mass m ?t 2and with the mass di?erence ?m ?t =m ?t 2?m ?t 1and the mixing angle θ?
t as parameters.In the context of the RG approach the running ?t
masses,derived from the ?t
mass matrix,are considered as an approximation for the physical masses.The range of the ?t
masses appearing in Fig.5has been constrained by requiring that the contribution of the third generation of scalar quarks to the ρ-parameter [17]does not exceed the value of 1.3·10?3,which corresponds to the resolution of ?ρ(=?1)when it is determined from experimental data [19].As in the comparison performed above,in Fig.5very good agreement
is found between the results of the two approaches in the case of vanishing ?t
mixing.For the maximal mixing angle θ?t =?π/4,however,the diagrammatic result yields values for m h which are higher by about 5GeV.
In summary,we have implemented the result of the Feynman-diagrammatic calculation of the leading O (ααs )corrections to the masses of the neutral CP -even Higgs bosons in the MSSM into the prediction based on the complete diagrammatic one-loop on-shell result.Two further re?nements have been added in order to incorporate leading electroweak two-loop and higher-order QCD contributions.In this way we provide the at present most precise
8
100
300
500
700900110013001500
m t
2
~ [GeV]20304050607080
90100110m h [G e V ]
θt ~ = 0, ?m t ~ = 0 GeV, diag. 2?loop
θt ~ = 0, ?m t ~ = 0 GeV, RG
θt ~ = ?π/4, ?m t ~ = 350 GeV, diag. 2?loop θt ~ = ?π/4, ?m t ~ = 350 GeV, RG
M A = 500 GeV, m g ~ = 500 GeV, tan β = 1.6M 2 = 400 GeV, μ = ?200 GeV
100
300500
700900110013001500
m t
2
~ [GeV]60
70
8090100110120
130140m h [G e V ]
θt ~ = 0, ?m t ~ = 0 GeV, diag. 2?loop
θt ~ = 0, ?m t ~ = 0 GeV, RG
θt ~ = ?π/4, ?m t ~ = 350 GeV, diag. 2?loop θt ~ = ?π/4, ?m t ~ = 350 GeV, RG
M A = 500 GeV, m g ~ = 500 GeV, tan β = 40M 2 = 400 GeV, μ = ?200 GeV
Figure 5:Comparison between the Feynman-diagrammatic calculations and the results
obtained by renormalization group methods [9].The mass of the lightest Higgs boson is shown for the two scenarios with tan β=1.6and tan β=40as a function of the heavier
physical ?t mass m ?t 2.For the curves with θ?t =0a mass di?erence ?m ?t =0GeV is assumed
whereas for θ?t =?π/4we chose ?m ?t =350GeV,for which the maximal Higgs masses are achieved.
prediction for m h based on Feynman-diagrammatic results.The results are valid for arbitrary values of the relevant MSSM parameters.The two-loop corrections lead to a large reduction of the one-loop on-shell result.Concerning the discovery and exclusion potential of LEP2,our results con?rm that the scenario with low tan β(tan β=1.6)in the MSSM should be covered at LEP2,while the scenario with high tan β(tan β=40)is only (partly)accessible for vanishing mixing in the scalar top sector.We have compared our results with the results obtained via RG methods,and have analyzed in this context the one-loop and two-loop contributions separately.We have found that the drastic deviations present between the one-loop on-shell result and the RG result are largely reduced.For the case of vanishing mixing in the scalar top sector the diagrammatic and the RG results agree very well,while
sizable deviations exceeding 5GeV occur when ?t
mixing is taken into account.Since the gluino mass does not appear as a parameter in the RG results,its variation gives rise to an extra deviation which lies within ±2GeV.We have discussed the issue of how the results obtained via di?erent approaches using di?erent renormalization schemes can be formulated such that they are readily comparable to each other also when corrections beyond one-loop order are incorporated.For this purpose it is very desirable to express the prediction for the Higgs-boson masses in terms of physical observables,i.e.the physical masses and mixing
9
angles of the model.
We thank M.Carena,H.Haber and C.Wagner for fruitful discussions and communication about the numerical comparison of our results.We also thank A.Djouadi and M.Spira for helpful discussions.
References
[1]G.Kane,C.Kolda and J.Wells,Phys.Rev.Lett.70(1993)2686;
J.Espinosa and M.Quir′o s,Phys.Lett.B302(1993)51;Phys.Rev.Lett.81(1998) 516.
[2]H.Haber and G.Kane,Phys.Rep.117(1985)75.
H.P.Nilles,Phys.Rep.110(1984)1.
[3]H.Haber and R.Hemp?ing,Phys.Rev.Lett.66(1991)1815;
Y.Okada,M.Yamaguchi and T.Yanagida,Prog.Theor.Phys.85(1991)1;
J.Ellis,G.Ridol?and F.Zwirner,Phys.Lett.B257(1991)83;Phys.Lett.B262 (1991)477;
R.Barbieri and M.Frigeni,Phys.Lett.B258(1991)395.
[4]P.Chankowski,S.Pokorski and J.Rosiek,Nucl.Phys.B423(1994)437.
[5]A.Dabelstein,Nucl.Phys.B456(1995)25;Z.Phys.C67(1995)495.
[6]J.Bagger,K.Matchev,D.Pierce and R.Zhang,Nucl.Phys.B491(1997)3.
[7]J.Casas,J.Espinosa,M.Quir′o s and A.Riotto,Nucl.Phys.B436(1995)3,E:ibid.
B439(1995)466.
[8]M.Carena,J.Espinosa,M.Quir′o s and C.Wagner,Phys.Lett.B355(1995)209.
[9]M.Carena,M.Quir′o s and C.Wagner,Nucl.Phys.B461(1996)407.
[10]H.Haber,R.Hemp?ing and A.Hoang,Z.Phys.C75(1997)539.
[11]R.Hemp?ing and A.Hoang,Phys.Lett.B331(1994)99.
[12]Reports of the Working Group on Precision Calculations for the Z-resonance,CERN
Yellow Report,CERN95-03,eds.D.Bardin,W.Hollik and G.Passarino.
[13]S.Heinemeyer,W.Hollik and G.Weiglein,KA-TP-2-1998,hep-ph/9803277,to appear
in Phys.Rev.D.
[14]M.Carena,P.Chankowski,S.Pokorski and C.Wagner,FERMILAB-PUB-98/146-T,
hep-ph/9805349.
10
[15]M.Carena and P.Zerwas,in Physics at LEP2,CERN96-01,eds.G.Altarelli,
T.Sj¨o strand and F.Zwirner.
[16]J.Gunion,H.Haber,G.Kane and S.Dawson,The Higgs Hunter’s Guide,Addison-
Wesley,1990.
[17]A.Djouadi,P.Gambino,S.Heinemeyer,W.Hollik,C.J¨u nger and G.Weiglein,Phys.
Rev.Lett.78(1997)3626;Phys.Rev.D57(1998)4179.
[18]M.Carena,S.Pokorski and C.Wagner,Nucl.Phys.B406(1993)59;
W.de Boer et al.,Z.Phys.C71(1996)415.
[19]G.Altarelli,XVIII Int.Symposium on Lepton–Photon Interactions,Hamburg1997,
CERN-TH97-278,hep-ph/9710434
11
to与for的用法和区别
to与for的用法和区别 一般情况下, to后面常接对象; for后面表示原因与目的为多。 Thank you for helping me. Thanks to all of you. to sb.表示对某人有直接影响比如，食物对某人好或者不好就用to; for表示从意义、价值等间接角度来说，例如对某人而言是重要的，就用for. for和to这两个介词，意义丰富，用法复杂。这里仅就它们主要用法进行比较。 1. 表示各种“目的” 1. What do you study English for? 你为什么要学英语？ 2. She went to france for holiday. 她到法国度假去了。 3. These books are written for pupils. 这些书是为学生些的。 4. hope for the best, prepare for the worst. 作最好的打算，作最坏的准备。 2．对于 1．She has a liking for painting. 她爱好绘画。 2．She had a natural gift for teaching. 她对教学有天赋/ 3．表示赞成同情，用for不用to. 1. Are you for the idea or against it? 你是支持还是反对这个想法？ 2. He expresses sympathy for the common people.. 他表现了对普通老百姓的同情。 3. I felt deeply sorry for my friend who was very ill. 4 for表示因为，由于（常有较活译法） 1 Thank you for coming. 谢谢你来。 2. France is famous for its wines. 法国因酒而出名。 5．当事人对某事的主观看法，对于（某人），对…来说（多和形容词连用）用介词to，不用for.. He said that money was not important to him. 他说钱对他并不重要。 To her it was rather unusual. 对她来说这是相当不寻常的。 They are cruel to animals. 他们对动物很残忍。 6．for和fit, good, bad, useful, suitable 等形容词连用，表示适宜，适合。 Some training will make them fit for the job. 经过一段训练，他们会胜任这项工作的。 Exercises are good for health. 锻炼有益于健康。 Smoking and drinking are bad for health. 抽烟喝酒对健康有害。 You are not suited for the kind of work you are doing. 7. for表示不定式逻辑上的主语，可以用在主语、表语、状语、定语中。 1．It would be best for you to write to him. 2．The simple thing is for him to resign at once. 3．There was nowhere else for me to go. 4．He opened a door and stood aside for her to pass.
(完整版)介词for用法归纳
介词for用法归纳 用法1：(表目的)为了。如： They went out for a walk. 他们出去散步了。 What did you do that for? 你干吗这样做？ That’s what we’re here for. 这正是我们来的目的。 What’s she gone for this time? 她这次去干什么去了？ He was waiting for the bus. 他在等公共汽车。 【用法说明】在通常情况下，英语不用for doing sth 来表示目的。如： 他去那儿看他叔叔。 误：He went there for seeing his uncle. 正：He went there to see his uncle. 但是，若一个动名词已名词化，则可与for 连用表目的。如： He went there for swimming. 他去那儿游泳。(swimming 已名词化) 注意：若不是表目的，而是表原因、用途等，则其后可接动名词。(见下面的有关用法) 用法2：(表利益)为，为了。如： What can I do for you? 你想要我什么？ We study hard for our motherland. 我们为祖国努力学习。 Would you please carry this for me? 请你替我提这个东西好吗？ Do more exercise for the good of your health. 为了健康你要多运动。 【用法说明】(1) 有些后接双宾语的动词(如buy, choose, cook, fetch, find, get, order, prepare, sing, spare 等)，当双宾语易位时，通常用for 来引出间接宾语，表示间接宾语为受益者。如： She made her daughter a dress. / She made a dress for her daughter. 她为她女儿做了件连衣裙。 He cooked us some potatoes. / He cooked some potatoes for us. 他为我们煮了些土豆。 注意，类似下面这样的句子必须用for： He bought a new chair for the office. 他为办公室买了张新办公椅。 (2) 注意不要按汉语字面意思，在一些及物动词后误加介词for： 他们决定在电视上为他们的新产品打广告。 误：They decided to advertise for their new product on TV. 正：They decided to advertise their new product on TV. 注：advertise 可用作及物或不及物动词，但含义不同：advertise sth＝为卖出某物而打广告；advertise for sth＝为寻找某物而打广告。如：advertise for a job=登广告求职。由于受汉语“为”的影响，而此处误加了介词for。类似地，汉语中的“为人民服务”，说成英语是serve the people，而不是serve for the people，“为某人的死报仇”，说成英语是avenge sb’s death，而不是avenge for sb’s death，等等。用法3：(表用途)用于，用来。如： Knives are used for cutting things. 小刀是用来切东西的。 This knife is for cutting bread. 这把小刀是用于切面包的。 It’s a machine for slicing bread. 这是切面包的机器。 The doctor gave her some medicine for her cold. 医生给了她一些感冒药。 用法4：为得到，为拿到，为取得。如： He went home for his book. 他回家拿书。 He went to his friend for advice. 他去向朋友请教。 She often asked her parents for money. 她经常向父母要钱。
医科达Precise型直线加速器真空故障维修研究
医科达Precise型直线加速器真空故障维修研究 发表时间：2019-07-18T12:42:30.247Z 来源：《科技尚品》2018年第10期作者：丁春江冯惠华戴晓敏梁兵梁卫聪 [导读] 随着我国科学技术的发展，医学设备也在不断的增加，而医科达Precise型直线加速器作为医院重要的医学设备，提高对其的故障检修是其中的重点和关键，本文从医科达加速器的概述、真空系统的组成以及医科达Precise型直线加速器真空故障维修等方面进行简要的分析和研究，进而为研究故障出现的原因和因素，针对其因素采取相应的解决方式，进而保障其加速器的正常运行。 开平市中心医院放疗中心 前言 在医院的临床手术中，医科达Precise型直线加速器是其中的重要设备，它的作用是避免加速管内放电击穿，防止电子枪阴极中毒，即钨丝材料的热子或灯丝氧化，减少电子与残余气体杂质的碰撞损失，因此，对医科达Precise型直线加速器真空系统的故障进行排除是其中的重要工作，在故障的排除中，要加强对原因的分析，并对故障进行科学的检修，进而保障加速器的正常使用。 1.医科达加速器的概述 1.1特点 在进行医科达加速器的真空系统的维修中，要先对医科达加速器进行熟悉和了解，通过对其结构和特征的熟悉，能够更加针对的预测其故障发生，其主要有以下几个特点： 首先，其加速器在使用的过程中可以避免加速管内放电击穿，进而提高加速器的使用效率，故此，该加速器具有较大的优势。 其次，在医院的使用中，医科达加速器可以避免出现钨丝材料灯丝或者热子氧化的问题，同时防止电子枪的阴极出现中毒的问题。 最后，医科达加速器能够有效降低电子和残余气体发生碰撞的概率，避免造成势能损失。 由此可见该直线加速器在医院的使用中能够提高其使用效率，并为医院的手术等提供高效率的使用，保障手术的正常进行。 1.2结构 在对医科达Precise型直线加速器进行分析中，要先对其结构进行熟悉，医科达Precise直线加速器是行波加速，用的是可拆卸密封的行渡加速管，其结构示意图如下： 从上图中可以看出，医科达Precise直线加速器的结构较为复杂，在进行故障的维修过程中，呀针对其结构进行故障分析，进而得出故障所在。故此，要加强对医科达直线加速器的结构分析，进而提高维修效率。 2.真空系统 在医科达Precise型直线加速器真空系统中，要对真空系统进行分析，其加速器的真空系统构成较为复杂，在进行故障的分析中，可以借助科学技术和信息技术对医科达直线加速器的真空系统进行检测，进而对其故障因素进行分析，进而保障真空系统的安稳运行，同时，加速器对真空的检测主要是通过对离子泵的工作电流的检测换算过来的，真空监测主要是加速器可以对真空度、真空联锁以及真空电路进行监测，在监测的过程中可以对加速器的情况进行观察。 3.医科达Precise型直线加速器真空故障维修 3.1故障表现 在对医科达Precise型直线加速器真空维修前要先对故障表现进行了解，进而能够快速的找到其故障所在。医科达加速器在使用的过程中，如果长时间的没有进行检修，其真空系统就会出现故障，进而影响加速器的使用，因此，在使用加速器要定期对其进行检修，医科达Precise直线加速器使用时起，如果在6MV电子线治疗模式时剂量不稳，同时低剂量联锁，治疗暂停，经常报Magnetron timer，其它电子线及X线治疗模式均正常，这时就是出现故障，需要对其加速器进行检修，这时，需要对加速器进行检修，故此，在医科达Precise型直线加速器使用过程中，要加强对其加速器故障的检测，如果一旦出现故障要及时进行处理，避免由于故障而影响其使用。 3.2故障分析和排除 在对医科达Precise型直线加速器的故障分析中，首先要先对其真空系统出现故障的因素进行分析，一般医科达直线加速器的真空故障有两个原因，其一是可能加速器的真空系统有泄漏点，该泄漏点导致真空系统出现故障，进而影响其正常使用，其二，可能加速器的 离子泵泵体故障损伤无法工作，这些是加速器真空系统可能出现故障的因素，通过对因素的分析进而对故障进行分析，在医科达工程师到达后，初步诊断为离子泵性能减退，通过测试，关闭枪端钛泵，靶端真空值上升，但是真空值还是未达到工作条件。再次判断为真空系统有泄漏点，在对故障分析完成之后，要对其可能出现的故障进行排除，找出真正出现故障的因素，在进行故障排除的过程中，针对一些可能出现的特殊故障要采取针对性的措施，进而进而提高故障排除的效率。 3.3故障处理 故障处理是加速器真空系统运行中的重要环节，在对医科达Precise型直线加速器真空系统的故障分析和排除之后，要对其故障进行处
of与for的用法以及区别
of与for的用法以及区别 for 表原因、目的 of 表从属关系 介词of的用法 （1）所有关系 this is a picture of a classroom （2）部分关系 a piece of paper a cup of tea a glass of water a bottle of milk what kind of football，American of soccer？ （3）描写关系 a man of thirty 三十岁的人 a man of shanghai 上海人 （4）承受动作 the exploitation of man by man．人对人的剥削。 （5）同位关系 It was a cold spring morning in the city of London in England． （6）关于，对于 What do you think of Chinese food？ 你觉得中国食品怎么样？ 介词 for 的用法小结 1. 表示“当作、作为”。如: I like some bread and milk for breakfast. 我喜欢把面包和牛奶作为早餐。What will we have for supper? 我们晚餐吃什么?
2. 表示理由或原因,意为“因为、由于”。如: Thank you for helping me with my English. 谢谢你帮我学习英语。 Thank you for your last letter. 谢谢你上次的来信。 Thank you for teaching us so well. 感谢你如此尽心地教我们。 3. 表示动作的对象或接受者,意为“给……”、“对…… (而言)”。如: Let me pick it up for you. 让我为你捡起来。 Watching TV too much is bad for your health. 看电视太多有害于你的健康。 4. 表示时间、距离,意为“计、达”。如: I usually do the running for an hour in the morning. 我早晨通常跑步一小时。We will stay there for two days. 我们将在那里逗留两天。 5. 表示去向、目的,意为“向、往、取、买”等。如: let’s go for a walk. 我们出去散步吧。 I came here for my schoolbag.我来这儿取书包。 I paid twenty yuan for the dictionary. 我花了20元买这本词典。 6. 表示所属关系或用途,意为“为、适于……的”。如: It’s time for school. 到上学的时间了。 Here is a letter for you. 这儿有你的一封信。 7. 表示“支持、赞成”。如: Are you for this plan or against it? 你是支持还是反对这个计划? 8. 用于一些固定搭配中。如: Who are you waiting for? 你在等谁? For example, Mr Green is a kind teacher. 比如,格林先生是一位心地善良的老师。
医科达电子直线加速器技术参数(上海
医科达电子直线加速器技术参数 1、双模式的数字化加速器，提供宽范围的X线和电子线能量，充分满足放射治疗外照射的临床需要。 2、射线束能量：多能量可定制性：多至2档X射线能量(4~18MV)和6档电子线能量(4~20MeV) 3、主机性能及配置： （1）独特设计的滚筒式机架：高度可靠性和稳定性，开放的机架结构，便于维修，最低的等中心高度（124cm），最大的等中心到治疗头的净空间距离45cm。 （2）高效能的行波加速管：行波加速管二十年无条件保用，允许较低的电压梯度，对行波加速管的真空要求低，使电子枪等部件可快速拆卸并易于更换。 （3）大功率FasTraQ磁控管：专门的紧凑型微波功率源，5MW功率输出，具有快速调谐的能力，快速的束流切换特性<0.1秒，提供24个月的保用期。 （4）滑雪式偏转系统：完全的消色散系统，并维持射束的对称性，伺服控制的三极磁偏转系统，精确的靶点聚焦，极佳的半影。（5）可单独拆卸更换灯丝的电子枪：电子枪伺服系统反应快速，确保束流能量的精度。
（6）六通道开放式结构的电离室：最新型超薄壁陶瓷材料电离室，自动校正KTP（温度、湿度、气压），监测射线的剂量、对称性和平坦度，具有长期的高灵敏和高稳定性，适合精确的伺服控制射线束流，重复精度：+/-0.5%，线性精度：+/-1%，2-10MU时的线性精度对保证IMRT的放疗精度尤其重要，旋转（运动束流）投照时的稳定性：±1%，分辨率：0.1MU。 （7）运动系统：用于操纵治疗头、机架及病人床的运动，手控盒可操纵加速器的所有动作，治疗头上有四个控制钮，可操纵治疗头的所有运动，治疗床两边各有一个控制板，可操纵床的所有运动，所有运动都是无线调速。 （8）安全连锁系统：通过硬件限位和软件防碰撞二种方式，确保病人和操作人员的安全。 （9）真空系统：维持加速管和电子枪的真空状态，在加速器中有效使用离子泵，有助于减少能源消耗，保护环境，并维持高的开机率。（10）水冷系统（内循环）：保证加速器的频率稳定，进而保证能量的稳定，用于加速器的热交换。 4、控制系统：全新的第三代全集成、全数字控制系统，确保更为平顺的流程工作方式，有效地提高治疗病人的周转率，基于Windows 平台的图形用户界面，易学习和使用，模块化软件结构，配置安装各
常用介词用法(for to with of)
For的用法 1. 表示“当作、作为”。如: I like some bread and milk for breakfast. 我喜欢把面包和牛奶作为早餐。 What will we have for supper? 我们晚餐吃什么? 2. 表示理由或原因,意为“因为、由于”。如: Thank you for helping me with my English. 谢谢你帮我学习英语。 3. 表示动作的对象或接受者,意为“给……”、“对…… (而言)”。如: Let me pick it up for you. 让我为你捡起来。 Watching TV too much is bad for your health. 看电视太多有害于你的健康。 4. 表示时间、距离,意为“计、达”。如: I usually do the running for an hour in the morning. 我早晨通常跑步一小时。 We will stay there for two days. 我们将在那里逗留两天。 5. 表示去向、目的,意为“向、往、取、买”等。如: Let’s go for a walk. 我们出去散步吧。 I came here for my schoolbag.我来这儿取书包。 I paid twenty yuan for the dictionary. 我花了20元买这本词典。 6. 表示所属关系或用途,意为“为、适于……的”。如: It’s time for school. 到上学的时间了。 Here is a letter for you. 这儿有你的一封信。 7. 表示“支持、赞成”。如: Are you for this plan or against it? 你是支持还是反对这个计划? 8. 用于一些固定搭配中。如: Who are you waiting for? 你在等谁? For example, Mr Green is a kind teacher. 比如,格林先生是一位心地善良的老师。 尽管for 的用法较多，但记住常用的几个就可以了。 to的用法: 一：表示相对，针对 be strange (common, new, familiar, peculiar) to This injection will make you immune to infection. 二：表示对比，比较 1：以-ior结尾的形容词，后接介词to表示比较，如：superior ,inferior,prior,senior,junior 2: 一些本身就含有比较或比拟意思的形容词，如equal，similar，equivalent，analogous A is similar to B in many ways.
of和for的用法
of 1....的,属于 One of the legs of the table is broken. 桌子的一条腿坏了。 Mr.Brown is a friend of mine. 布朗先生是我的朋友。 2.用...做成的;由...制成 The house is of stone. 这房子是石建的。 3.含有...的;装有...的 4....之中的;...的成员 Of all the students in this class,Tom is the best. 在这个班级中,汤姆是最优秀的。 5.(表示同位) He came to New York at the age of ten. 他在十岁时来到纽约。 6.(表示宾格关系) He gave a lecture on the use of solar energy. 他就太阳能的利用作了一场讲演。 7.(表示主格关系) We waited for the arrival of the next bus. 我们等待下一班汽车的到来。
I have the complete works of Shakespeare. 我有莎士比亚全集。 8.来自...的;出自 He was a graduate of the University of Hawaii. 他是夏威夷大学的毕业生。 9.因为 Her son died of hepatitis. 她儿子因患肝炎而死。 10.在...方面 My aunt is hard of hearing. 我姑妈耳朵有点聋。 11.【美】(时间)在...之前 12.(表示具有某种性质) It is a matter of importance. 这是一件重要的事。 For 1.为,为了 They fought for national independence. 他们为民族独立而战。 This letter is for you. 这是你的信。
医科达直线加速器参数
Precise全数字直线加速器 双模式的数字化加速器，提供宽围的X线和电子线能量，充分满足放射治疗外照射的临床需要。 具有如下详述的特征和配置： 1.0 射线束能量 Precise数字化加速器具有无可匹敌的多能量可定制性：2档X射线能量（4~15MV）和9档电子线能量（4~22MeV） 2.0 Precise全数字直线加速器主机系统包含如下特性： 独特设计的滚筒式机架直线加速器 -由强劲的刚性结构带来的高度可靠性和稳定性 -开放的机架结构，便于维修，需维护的重要部件均分布在易于接近的位置 -最低的等中心高度（124cm），具有最优的临床可用性 -最大的等中心到治疗头的净空间距离45cm 高效能的行波加速管 -行波加速管二十年无条件保用 -允许较低的电压梯度，对行波加速管的真空要求低，使电子枪等部件可快速拆卸并易于更换 大功率FasTraQ磁控管： -专门的紧凑型微波功率源，5MW功率输出，具有快速调谐的能力 -快速的束流切换特性<0.1秒 -提供24个月的保用期 独有的滑雪式偏转系统： -完全的消色散系统，并维持射束的对称性 -伺服控制的三极磁偏转系统 -精确的靶点聚焦，极佳的半影 可单独拆卸更换灯丝的电子枪 -电子枪伺服系统反应快速，确保束流能量的精度 -易于更换，维护费用低 六通道开放式结构的电离室 -最新型超薄壁瓷材料电离室 -自动校正KTP（温度、湿度、气压），监测射线的剂量、对称性和平坦度 -具有长期的高灵敏和高稳定性，适合精确的伺服控制射线束流 -重复精度：+/-0.5% -线性精度：+/-1% -2-10MU时的线性精度对保证IMRT的放疗精度尤其重要 -旋转（运动束流）投照时的稳定性：±1% -分辨率：0.1MU 运动系统 -用于操纵治疗头、机架及病人床的运动 -手控盒可操纵加速器的所有动作
双宾语 to for的用法
1.两者都可以引出间接宾语，但要根据不同的动词分别选用介词to 或for：(1) 在give, pass, hand, lend, send, tell, bring, show, pay, read, return, write, offer, teach, throw 等之后接介词to。 如： 请把那本字典递给我。 正：Please hand me that dictionary. 正：Please hand that dictionary to me. 她去年教我们的音乐。 正：She taught us music last year. 正：She taught music to us last year. (2) 在buy, make, get, order, cook, sing, fetch, play, find, paint, choose,prepare, spare 等之后用介词for 。如： 他为我们唱了首英语歌。 正：He sang us an English song. 正：He sang an English song for us. 请帮我把钥匙找到。 正：Please find me the keys. 正：Please find the keys for me. 能耽搁你几分钟吗(即你能为我抽出几分钟吗)? 正：Can you spare me a few minutes? 正：Can you spare a few minutes for me? 注：有的动词由于搭配和含义的不同，用介词to 或for 都是可能的。如：do sb a favour＝do a favour for sb 帮某人的忙 do sb harm＝do harm to sb 对某人有害
for和to区别
1.表示各种“目的”，用for （1）What do you study English for 你为什么要学英语？ （2）went to france for holiday. 她到法国度假去了。 （3）These books are written for pupils. 这些书是为学生些的。 （4）hope for the best, prepare for the worst. 作最好的打算，作最坏的准备。 2．“对于”用for （1）She has a liking for painting. 她爱好绘画。 （2）She had a natural gift for teaching. 她对教学有天赋/ 3．表示“赞成、同情”，用for （1）Are you for the idea or against it 你是支持还是反对这个想法？ （2）He expresses sympathy for the common people.. 他表现了对普通老百姓的同情。 （3）I felt deeply sorry for my friend who was very ill. 4. 表示“因为，由于”（常有较活译法），用for （1）Thank you for coming. 谢谢你来。
（2）France is famous for its wines. 法国因酒而出名。 5．当事人对某事的主观看法，“对于（某人），对…来说”，（多和形容词连用），用介词to，不用for. （1）He said that money was not important to him. 他说钱对他并不重要。 （2）To her it was rather unusual. 对她来说这是相当不寻常的。 （3）They are cruel to animals. 他们对动物很残忍。 6．和fit, good, bad, useful, suitable 等形容词连用，表示“适宜，适合”，用for。（1）Some training will make them fit for the job. 经过一段训练，他们会胜任这项工作的。 （2）Exercises are good for health. 锻炼有益于健康。 （3）Smoking and drinking are bad for health. 抽烟喝酒对健康有害。 （4）You are not suited for the kind of work you are doing. 7. 表示不定式逻辑上的主语，可以用在主语、表语、状语、定语中。 （1）It would be best for you to write to him. （2） The simple thing is for him to resign at once.
for和of的用法
for的用法： 1. 表示“当作、作为”。如: I like some bread and milk for breakfast. 我喜欢把面包和牛奶作为早餐。 What will we have for supper? 我们晚餐吃什么? 2. 表示理由或原因,意为“因为、由于”。如: Thank you for helping me with my English. 谢谢你帮我学习英语。 Thank you for your last letter. 谢谢你上次的来信。 Thank you for teaching us so well. 感谢你如此尽心地教我们。 3. 表示动作的对象或接受者,意为“给……”、“对…… (而言)”。如: Let me pick it up for you. 让我为你捡起来。 Watching TV too much is bad for your health. 看电视太多有害于你的健康。 4. 表示时间、距离,意为“计、达”。如:
I usually do the running for an hour in the morning. 我早晨通常跑步一小时。 We will stay there for two days. 我们将在那里逗留两天。 5. 表示去向、目的,意为“向、往、取、买”等。如: Let’s go for a walk. 我们出去散步吧。 I came here for my schoolbag.我来这儿取书包。 I paid twenty yuan for the dictionary. 我花了20元买这本词典。 6. 表示所属关系或用途,意为“为、适于……的”。如: It’s time for school. 到上学的时间了。 Here is a letter for you. 这儿有你的一封信。 7. 表示“支持、赞成”。如: Are you for this plan or against it? 你是支持还是反对这个计划? 8. 用于一些固定搭配中。如:
加速器相关英语缩略语定义(医科达)
加速器缩略语定义Abbreviation Definition ABCActive BreathingCoordinator主动呼吸协调器 ACBarm control board 臂控制板 AFCautomatic frequencycontrol 自动频率控制 AFDaxis filmdistance 轴向膜距 AIangiographicimage血管造影图像 ALARPas low as reasonablepracticable尽可能低 AmSiAmorphousSilicon 非晶硅 APSAutomatic PositioningSystem?自动定位系统? ASUassisted setup辅助设置 BCBendingCoarse弯曲粗 BEVbeam eyeview光束视角 BFBendingFine弯曲细度 BLDbeam limitingdevice限束装置 BLSbeam limitingsystem束流限制系统 BMPBitmap (imageformat)位图(图像格式) BOMbill ofmaterials材料单 CANcontroller area network控制器局域网 CATcustomer acceptancetests客户验收试验 CAXcentralaxis中央轴，中心轴 CBcircuitbreaker]断路器 CCcouchcontrol 床控制 CCPCAN calibrationprotocol CAN校准协议 CCTVclosed circuittelevision 闭路电视 CDcompactdisc CITP clients interface terminal panel (interface between Elekta product and client hardware)客户界面终端面板（Elekta产品与客户端硬件之间的接口） CMMcorrective maintenancemanual校正维护手册 CMUMClinical Mode User’s Manual 临床模式用户手册 CRPcommon referencepoint 公共参考点 CTComputerizedTomography计算机X射线断层
双宾语tofor的用法
1. 两者都可以引出间接宾语，但要根据不同的动词分别选用介词to 或for： (1) 在give, pass, hand, lend, send, tell, bring, show, pay, read, return, write, offer, teach, throw 等之后接介词to。 如： 请把那本字典递给我。 正：Please hand me that dictionary. 正：Please hand that dictionary to me. 她去年教我们的音乐。 正：She taught us music last year. 正：She taught music to us last year. (2) 在buy, make, get, order, cook, sing, fetch, play, find, paint, choose,prepare, spare 等之后用介词for 。如： 他为我们唱了首英语歌。 正：He sang us an English song. 正：He sang an English song for us. 请帮我把钥匙找到。 正：Please find me the keys. 正：Please find the keys for me. 能耽搁你几分钟吗(即你能为我抽出几分钟吗)? 正：Can you spare me a few minutes? 正：Can you spare a few minutes for me? 注：有的动词由于搭配和含义的不同，用介词to 或for 都是可能的。如： do sb a favou r do a favour for sb 帮某人的忙 do sb harnn= do harm to sb 对某人有害
常用介词用法(for-to-with-of)
常用介词用法(for-to-with-of)
For的用法 1. 表示“当作、作为”。如: I like some bread and milk for breakfast. 我喜欢把面包和牛奶作为早餐。 What will we have for supper? 我们晚餐吃什么? 2. 表示理由或原因,意为“因为、由于”。如: Thank you for helping me with my English. 谢谢你帮我学习英语。 3. 表示动作的对象或接受者,意为“给……”、“对…… (而言)”。如: Let me pick it up for you. 让我为你捡起来。Watching TV too much is bad for your health. 看电视太多有害于你的健康。 4. 表示时间、距离,意为“计、达”。如: I usually do the running for an hour in the morning. 我早晨通常跑步一小时。 We will stay there for two days. 我们将在那里逗留两天。
5. 表示去向、目的,意为“向、往、取、买”等。如: Let’s go for a walk. 我们出去散步吧。 I came here for my schoolbag.我来这儿取书包。 I paid twenty yuan for the dictionary. 我花了20元买这本词典。 6. 表示所属关系或用途,意为“为、适于……的”。如: It’s time for school. 到上学的时间了。 Here is a letter for you. 这儿有你的一封信。 7. 表示“支持、赞成”。如: Are you for this plan or against it? 你是支持还是反对这个计划? 8. 用于一些固定搭配中。如: Who are you waiting for? 你在等谁? For example, Mr Green is a kind teacher. 比如,格林先生是一位心地善良的老师。
to和for的用法有什么不同(一)
to和for的用法有什么不同（一） 一、引出间接宾语时的区别 两者都可以引出间接宾语，但要根据不同的动词分别选用介词to 或for，具体应注意以下三种情况： 1. 在give, pass, hand, lend, send, tell, bring, show, pay, read, return, write, offer, teach, throw 等之后接介词to。如： 请把那本字典递给我。 正：Please hand me that dictionary. 正：Please hand that dictionary to me. 她去年教我们的音乐。 正：She taught us music last year. 正：She taught music to us last year. 2. 在buy, make, get, order, cook, sing, fetch, play, find, paint, choose, prepare, spare 等之后用介词for 。如： 他为我们唱了首英语歌。 正：He sang us an English song. 正：He sang an English song for us. 请帮我把钥匙找到。 正：Please find me the keys. 正：Please find the keys for me. 能耽搁你几分钟吗(即你能为我抽出几分钟吗)? 正：Can you spare me a few minutes?
正：Can you spare a few minutes for me? 3. 有的动词由于用法和含义不同，用介词to 或for 都是可能的。如： do sb a favor＝do a favor for sb 帮某人的忙 do sb harm＝do harm to sb 对某人有害 在有的情况下，可能既不用for 也不用to，而用其他的介词。如： play sb a trick＝play a trick on sb 作弄某人 请比较： play sb some folk songs＝play some folk songs for sb 给某人演奏民歌 有时同一个动词，由于用法不同，所搭配的介词也可能不同，如leave sbsth 这一结构，若表示一般意义的为某人留下某物，则用介词for 引出间接宾语，即说leave sth for sb；若表示某人死后遗留下某物，则用介词to 引出间接宾语，即说leave sth to sb。如： Would you like to leave him a message? / Would you like to leave a message for him? 你要不要给他留个话？ Her father left her a large fortune. / Her father left a large fortune to her. 她父亲死后给她留下了一大笔财产。 二、表示目标或方向的区别 两者均可表示目标、目的地、方向等，此时也要根据不同动词分别对待。如： 1. 在come, go, walk, move, fly, ride, drive, march, return 等动词之后通常用介词to 表示目标或目的地。如： He has gone to Shanghai. 他到上海去了。 They walked to a river. 他们走到一条河边。
英语形容词和of for 的用法
加入收藏夹 主题： 介词试题It’s + 形容词 + of sb. to do sth.和It’s + 形容词 + for sb. to do sth.的用法区别。 内容： It's very nice___pictures for me. A.of you to draw B.for you to draw C.for you drawing C.of you drawing 提交人：杨天若时间：1/23/2008 20:5:54 主题：for 与of 的辨别 内容：It's very nice___pictures for me. A.of you to draw B.for you to draw C.for you drawing C.of you drawing 答：选A 解析：该题考查的句型It’s + 形容词+ of sb. to do sth.和It’s +形容词+ for sb. to do sth.的用法区别。 “It’s + 形容词+ to do sth.”中常用of或for引出不定式的行为者，究竟用of sb.还是用for sb.，取决于前面的形容词。 1) 若形容词是描述不定式行为者的性格、品质的，如kind，good，nice，right，wrong，clever，careless，polite，foolish等，用of sb. 例： It’s very kind of you to help me. 你能帮我，真好。 It’s clever of you to work out the maths problem. 你真聪明，解出了这道数学题。 2) 若形容词仅仅是描述事物，不是对不定式行为者的品格进行评价，用for sb.，这类形容词有difficult，easy，hard，important，dangerous，（im）possible等。例： It’s very dangerous for children to cross the busy street. 对孩子们来说，穿过繁忙的街道很危险。 It’s difficult for u s to finish the work. 对我们来说，完成这项工作很困难。 for 与of 的辨别方法： 用介词后面的代词作主语，用介词前边的形容词作表语，造个句子。如果道理上通顺用of，不通则用for. 如： You are nice.(通顺，所以应用of)。 He is hard.(人是困难的，不通，因此应用for.) 由此可知，该题的正确答案应该为A项。 提交人：f7_liyf 时间：1/24/2008 11:18:42