Low-Energy Effective Action in N=4 Super Yang-Mills Theory

合集下载

E-S-C

如果这使您听起来感觉很美好以至于不真实，我们很乐意与您分享我们关于气动方面的能源效率的知识和技术！
产品信息 Product Information
As world leaders in pneumatics, our experts have developed some of the most innovative products and activities for compressed air systems which will help you save money as well as helping in the fight to protect our environment.
作为气动领域的领头者，我们的专家开发出了最具创新性的产品和压缩空气系统，这将有助于您节省资金，以及我们共同进行保护我们环境的一些活动。
These products will detect leaks, lower power consumption, decrease air wastage, reduce piping requirements, optimise your pressure levels and ensure efficient vacuum generation.
Series PFM and PF2A Digital Flow Switches - developed to monitor air line pressure ensuring that any wasteful leaks are identified and can be measured accurately.
Series ASR/ASQ Pressure and Flow Valves - realise energy savings by using these improved pressure and flow valves which can cut air consumption by up to 40%, by effectively reducing the pressure required to operate the cylinder’s return stroke. 通过使用这些改进的压力和流量阀，降低气缸回程的压力，可减少高达40％的空气消耗，实现节约能源。

轮胎配方设计4

四、压延(calendering)
压延胶料应具有：良好的包辊性（既不能粘辊，也不能脱辊）良好的流动性（保证胶料外观质量）抗焦烧性（加工安全性）低收缩性（复合制品的外观及工艺性） 1．生胶：NR>BR>SBR>NBR>IIR，门尼粘度低的胶料工艺性较好。通常压延胶料的ML1+4100应控制在60以下经验数据：压片胶料 50～60 贴胶胶料 40～50 擦胶胶料 30～40
１、胶种的选择：选用SSBR，TPI，1,2-聚丁二烯，集成橡胶(SIBR) 如将 65 份溶聚丁苯胶、 35 份 RSS 3( 烟片胶 ) 、 30 份 Seast KH( 炭黑 ) 、 30 份 NZPsil AQ( 二氧化硅 ) 、 3份Si69、2份二甲醇、3份氧化锌、1份Lunac YA、 1.5份 Antigen 6C以及 0.5份 Sunnoc 组成胶料，再和 1.7 份 Nocceter NS-F 与 1.7 份油处理过的硫黄一起混炼，在160℃下加压硫化制成试样。试验表明：在 0℃和 60℃下其介质损耗角正切 tanδ分别为0.572和0.153。在轿车和轻型载重半钢丝子午胎的胎面胶中，用20～25质量份SSBR取代等量的乳聚丁苯胶，轮胎滚动阻力即可减小10％，降低汽车燃油消耗2％左右(时速100Km／h)
625
1.1 2.32
659
0.9 2.13
702
0.8 1.97
724
0.78 1.94
743
0.76 1.92
746
0.74 1.9
2）生胶的选择橡胶不同门尼粘度，如NBR2865 和3445 加工要求：挤出制品：门尼粘度≤60 压延贴胶：门尼粘度≤50 压延擦胶：门尼粘度≤40 海绵制品：门尼粘度更低但有特殊情况，如耐热垫圈，需高温低压变，可采用高门尼值的橡胶。 3) 加入填充剂（用量大，粒径小）使胶料粘度增加，加入软化剂使胶料粘度下降。

standard model标准模型

CPT violation and the standard modelDon Colladay and V.Alan Kostelecky´Department of Physics,Indiana University,Bloomington,Indiana47405͑Received22January1997͒Spontaneous CPT breaking arising in string theory has been suggested as a possible observable experimen-tal signature in neutral-meson systems.We provide a theoretical framework for the treatment of low-energy effects of spontaneous CPT violation and the attendant partial Lorentz breaking.The analysis is within the context of conventional relativistic quantum mechanics and quantumﬁeld theory in four dimensions.We use the framework to develop a CPT-violating extension to the minimal standard model that could serve as a basis for establishing quantitative CPT bounds.͓S0556-2821͑97͒05211-9͔PACS number͑s͒:11.30.Er,11.25.Ϫw,12.60.ϪiI.INTRODUCTIONAmong the symmetries of the minimal standard model is invariance under CPT.Indeed,CPT invariance holds under mild technical assumptions for any local relativistic point-particleﬁeld theory͓1–5͔.Numerous experiments have con-ﬁrmed this result͓6͔,including in particular high-precision tests using neutral-kaon interferometry͓7,8͔.The simulta-neous existence of a general theoretical proof of CPT invari-ance in particle physics and accurate experimental tests makes CPT violation an attractive candidate signature for nonparticle physics such as string theory͓9,10͔.The assumptions needed to prove the CPT theorem are invalid for strings,which are extended objects.Moreover, since the critical string dimensionality is larger than four,it is plausible that higher-dimensional Lorentz breaking would be incorporated in a realistic model.In fact,a mechanism is known in string theory that can cause spontaneous CPT vio-lation͓9͔with accompanying partial Lorentz-symmetry breaking͓11͔.The effect can be traced to string interactions that are absent in conventional four-dimensional renormaliz-able gauge theory.Under suitable circumstances,these inter-actions can cause instabilities in Lorentz-tensor potentials, thereby inducing spontaneous CPT and Lorentz breaking.If in a realistic theory the spontaneous CPT and partial Lorentz violation extend to the four-dimensional spacetime,detect-able effects might occur in interferometric experiments with neutral kaons͓9,10͔,neutral B d or B s mesons͓10,12͔,or neutral D mesons͓10,13͔.For example,the quantities pa-rametrizing indirect CPT violation in these systems could be nonzero.There may also be implications for baryogenesis ͓14͔.In the present paper,our goal is to develop within an effective-theory approach a plausible CPT-violating exten-sion of the minimal standard model that provides a theoreti-cal basis for establishing quantitative bounds on CPT invari-ance.The idea is to incorporate notions of spontaneous CPT and Lorentz breaking while maintaining the usual gauge structure and properties like renormalizability.To achieve this,weﬁrst establish a conceptual framework and a procedure for treating spontaneous CPT and Lorentz viola-tion in the context of conventional quantum theory.We seek a general methodology that is compatible with desirable fea-tures like microscopic causality while being sufﬁciently de-tailed to permit explicit calculations.We suppose that underlying the effective four-dimensional action is a complete fundamental theory that is based on conventional quantum physics͓15͔and is dynami-cally CPT and Poincare´invariant.The fundamental theory is assumed to undergo spontaneous CPT and Lorentz breaking. In a Poincare´-observer frame in the low-energy effective ac-tion,this process is taken toﬁx the form of any CPT-and Lorentz-violating terms.Since interferometric tests of CPT violation are so sensi-tive,we focus speciﬁcally on CPT violation and the associ-ated Lorentz-breaking issues in a low-energy effective theory without gravity͓21͔.For the most part,effects from deriva-tive couplings and possible CPT-preserving but Lorentz-breaking terms in the action are disregarded,and any CPT-violating terms are taken to be small enough to avoid issues with standard experimental tests of Lorentz symmetry.A partial justiﬁcation for the latter assumption is that the absence of signals for CPT violation in the neutral-kaonsystem provides one of the best bounds on Lorentz invari-ance.Our focus on the low-energy effective model bypassesvarious important theoretical issues regarding the structure ofthe underlying fundamental theory and its behavior at scalesabove electroweak uniﬁcation,including the origin and ͑renormalization-group͒stability of the suppression of CPT breaking and the issue of modeﬂuctuations around Lorentz-tensor expectation values.Since these topics involve the Lor-entz structure of the fundamental theory,they are likely to berelated to the difﬁcult hierarchy problems associated withcompactiﬁcation and the cosmological constant.The ideas underlying our theoretical framework are de-scribed in Sec.II.A simple model is used to illustrate con-cepts associated with CPT and Lorentz breaking,including the possibility of eliminating some CPT-violating effects throughﬁeld redeﬁnitions.The associated relativistic quan-tum mechanics is discussed in Sec.III.Section IV contains a treatment of some issues in quantumﬁeld theory.A CPT-violating extension of the minimal standard model is provided in Sec.V,and the physically observable subset ofPHYSICAL REVIEW D1JUNE1997VOLUME55,NUMBER11550556-2821/97/55͑11͒/6760͑15͒/$10.006760©1997The American Physical SocietyCPT-breaking terms is established.We summarize in Sec. VI.Some of the more technical results are presented in the appendixes.II.BASICSA.Effective model for spontaneous CPT violationWe begin our considerations with a simple model within which many of the basic features of spontaneous CPT vio-lation can be examined.The model involves a single massive Diracﬁeld␺(x)in four dimensions with Lagrangian densityLϭL0ϪLЈ,͑1͒where L0is the usual free-ﬁeld Dirac Lagrangian for a fer-mion␺of mass m,and where LЈcontains extra CPT-violating terms to be described below.For the present discussion,we follow an approach in which the C,P,T and Lorentz properties of␺are assumed to be conventionally determined by the free-ﬁeld theory L0and are used to estab-lish the corresponding properties of LЈ͓22͔.This method is intrinsically perturbative,which is particularly appropriate here since any CPT-violating effects must be small.In Sec. II C,we consider the possibility of alternative deﬁnitions of C,P,T and Lorentz properties that could encompass the full structure of L.We are interested in possible forms of LЈthat could arise as effective contributions from spontaneous CPT violation in a more complete theory.To our knowledge,string theory forms the only class of͑gauge͒theories in four or more dimensions that are quantum consistent,dynamically Poin-care´invariant,and known to admit an explicit mechanism ͓9͔for spontaneous CPT violation triggered by interactions in the Lagrangian.However,to keep the treatment as general as possible we assume only that the spontaneous CPT vio-lation arises from nonzero expectation values acquired by one or more Lorentz tensors T,so LЈis taken to be an effective four-dimensional Lagrangian obtained from an un-derlying theory involving Poincare´-invariant interactions of ␺with T.The discussion that follows is independent of any speciﬁcs of string theory and should therefore be relevant to a nonstring model with spontaneous CPT violation,if such a model is eventually formulated.Even applying the stringent requirement of dynamical Poincare´invariance,an unbroken realistic theory can in prin-ciple include terms with derivatives,powers of tensorﬁelds, and powers of various terms quadratic in fermionﬁelds. However,any CPT-breaking term that is to be part of a four-dimensional effective theory must have mass dimension four.In the effective Lagrangian,each combination ofﬁelds and derivatives of dimension greater than four therefore must have a corresponding weighting factor of a negative power Ϫk of at least one mass scale M that is large compared to the scale m of the effective theory.In a realistic theory with the string scenario,M might be the Planck mass or perhaps a smaller mass scale associated with compactiﬁcation and uni-ﬁcation.Moreover,since the expectations͗T͘of the tensors T are assumed to be Lorentz and possibly CPT violating, any terms that survive in LЈafter the spontaneous symmetry breaking must on physical grounds be suppressed,presum-ably by at least one power of m/M relative to the scale of the effective theory.A hierarchy of possible terms in LЈthus emerges,labeled by kϭ0,1,2,....Omitting Lorentz indices for simplicity,the leading terms with kр2have the schematic formLЈʛ␭M k͗T͘•␺¯⌫͑iץ͒k␺ϩH.c.͑2͒In this expression,the parameter␭is a dimensionless cou-pling constant,(iץ)k represents k four-derivatives acting in some combination on the fermionﬁelds,and⌫represents some gamma-matrix structure.Terms with kу3and with more quadratic fermion factors also appear,but these are further suppressed.Note that contributions of the form͑2͒arise in string theory͓10͔.Note also that naive power count-ing indicates the dominant terms with kр1are renormaliz-able.For kϭ0,the above considerations indicate that the domi-nant terms of the form͑2͒must have expectations͗T͘ϳm2/M.In the present work,we focus primarily on this relatively simple case.Most of the general features arising from CPT and Lorentz violation together with some of our more speciﬁc results remain valid when terms with other values of k are considered,but it remains an open issue to investigate the detailed properties of terms with kϭ1and expectations͗T͘ϳm or those with kϭ2and expectations ͗T͘ϳM.Both these could in principle contribute leading effects in the low-energy effective action.Each contribution to LЈfrom an expression of the form ͑2͒is a fermion bilinear involving a4ϫ4spinor matrix⌫. Regardless of the complexity and number of the tensors T inducing the breaking,⌫can be decomposed as a linear com-bination of the usual16basis elements of the gamma-matrix algebra.Only the subset of these that produce CPT-violating bilinears are of interest for our present pur-poses,and they permit us to provide explicit and relatively simple expressions for the possible CPT-violating contribu-tions to LЈ.For the case kϭ0of interest here,weﬁnd two possible types of CPT-violating term:L aЈϵa␮␺¯␥␮␺,L bЈϵb␮␺¯␥5␥␮␺.͑3͒For completeness,we provide here also the terms appearing for the case kϭ1,where weﬁnd three types of relevant contribution:L cЈϵ12ic␣␺¯ץJ␣␺,L dЈϵ12d␣␺¯␥5ץJ␣␺,L eЈϵ12ie␮␯␣␺¯␴␮␯ץJ␣␺,͑4͒where AץJ␮BϵAץ␮BϪ(ץ␮A)B.In all these expressions,the quantities a␮,b␮,c␣,d␣,and e␮␯␣must be real as conse-quences of their origins in spontaneous symmetry breaking and of the presumed hermiticity of the underlying theory. They are combinations of coupling constants,tensor expec-tations,mass parameters,and coefﬁcients arising from the decomposition of⌫.In keeping with their interpretation as effective coupling constants arising from a scenario with spontaneous symme-try breaking,a␮,b␮,c␣,d␣,and e␮␯␣are invariant under CPT transformations.Together with the standard556761CPT VIOLATION AND THE STANDARD MODELCPT-transformation properties ascribed to␺,this invariance causes the terms in Eqs.͑3͒and͑4͒to break CPT͓23͔.As discussed above,in the remainder of this work we restrict ourselves largely to the expressions in Eq.͑3͒.Allowing both kinds of term in Eq.͑3͒to appear in LЈproduces a model Lagrangian of the formLϭ12i␺¯␥␮ץJ␮␺Ϫa␮␺¯␥␮␺Ϫb␮␺¯␥5␥␮␺Ϫm␺¯␺.͑5͒The variational procedure generates a modiﬁed Dirac equa-tion:͑i␥␮ץ␮Ϫa␮␥␮Ϫb␮␥5␥␮Ϫm͒␺ϭ0.͑6͒Associated with this Dirac-type equation is a modiﬁed Klein-Gordon equation.Proceeding with the usual squaring procedure,in which the Dirac-equation operator with oppo-site mass sign is applied to the Dirac equation from the left, leads to the Klein-Gordon-type expression͓͑iץϪa͒2Ϫb2Ϫm2ϩ2i␥5␴␮␯b␮͑iץ␯Ϫa␯͔͒␺͑x͒ϭ0.͑7͒This equation is second order in derivatives,but unlike the usual Klein-Gordon case it contains off-diagonal terms in the spinor space.These may be eliminated by repeating the squaring procedure,this time applying the operator in Eq.͑7͒with opposite sign for the off-diagonal piece.The result is a fourth-order equation satisﬁed by each spinor component of any solution to the modiﬁed Dirac equation:͕͓͑iץϪa͒2Ϫb2Ϫm2͔2ϩ4b2͑iץϪa͒2Ϫ4͓b␮͑iץ␮Ϫa␮͔͒2͖␺͑x͒ϭ0.͑8͒B.Continuous symmetriesConsider next the continuous symmetries of the model with Lagrangian͑5͒.For deﬁniteness,we begin with an analysis in a given oriented inertial frame in which values of the quantities a␮and b␮are assumed to have been speciﬁed. The effects of rotations and boosts are considered later.The CPT-violating terms in Eq.͑5͒leave unaffected the usual global U͑1͒gauge invariance,which has conserved current j␮ϭ␺¯␥␮␺.Charge is therefore conserved in the model.These terms also leave unaffected the usual breaking of the chiral U͑1͒current j5␮ϭ␺¯␥5␥␮␺due to the mass term. In what follows,we denote the volume integrals of the cur-rent densities j␮and j5␮by J␮and J5␮,respectively.The model is also invariant under translations provided the tensor expectations are assumed constant,i.e.,provided the possibility of CPT-breaking soliton-type solutions in the underlying theory is disregarded.This leads to a conserved canonical energy-momentum tensor⌰␮␯given by⌰␮␯ϭ12i␺¯␥␮ץJ␯␺,ץ␮⌰␮␯ϭ0,͑9͒and a corresponding conserved four-momentum P␮.These expressions have the same form as in the free theory.Note, however,that constancy of the energy and momentum does not necessarily imply conventional behavior under boosts or rotations.Note also that the presence of the CPT-violating terms in the Dirac equation destroys the usual symmetriz-ability property of⌰␮␯.The antisymmetric part⌰͓␮␯͔is⌰͓␮␯͔ϵ⌰␮␯Ϫ⌰␯␮ϭϪ14ץ␣͓␺¯͕␥␣,␴␮␯͖␺͔Ϫa[␮j␯]Ϫb[␮j5␯],͑10͒which is no longer a total divergence.The conventional con-struction of a symmetric energy-momentum tensor,involv-ing a subtraction of this antisymmetric part from the canoni-cal energy-momentum tensor,would affect the conserved energy and momentum and is therefore presumably inappli-cable in the present case.The implications of this for a more complete low-energy effective theory that includes gravity remain to be explored.Next,consider the effect of Lorentz transformations,i.e., rotations and boosts.Conventional Lorentz transformations in special relativity relate observations made in two inertial frames with differing orientations and velocities.These transformations can be implemented as coordinate changes, and we call them observer Lorentz transformations.It is also possible to consider transformations that relate the properties of two particles with differing spin orientation or momentum within a speciﬁc oriented inertial frame.We call these par-ticle Lorentz transformations.For free particles under usual circumstances,the two kinds of transformation are͑in-versely͒related.However,this equivalence fails for particles under the action of a backgroundﬁeld.The reader is warned to avoid confusing observer Lorentz transformations͑which involve coordinate changes͒or par-ticle Lorentz transformations͑which involve boosts on par-ticles or localizedﬁelds but not on backgroundﬁelds͒with a third type of Lorentz transformation that within a speciﬁed inertial frame boosts all particles andﬁelds simultaneously, including background ones.The latter are sometimes called ͑inverse͒active Lorentz transformations.For the case of con-ventional free particles,they coincide with particle Lorentz transformations.We have chosen to avoid applying the terms active and passive here because they are insufﬁcient to dis-tinguish the three kinds of transformation and because in any case their interpretation varies in the literature.The distinction between observer and particle transforma-tions is relevant for the present model,where the CPT-violating terms can be regarded as arising from con-stant backgroundﬁelds a␮and b␮.The point is that these eight quantities transform as two four-vectors under observer Lorentz transformations and as eight scalars under particle Lorentz transformations,whereas they are coupled to cur-rents that transform as four-vectors under both types of trans-formation.This means that observer Lorentz symmetry is still an invariance of the model,but the particle Lorentz group is͑partly͒broken.Physical situations with features like this can readily be identiﬁed.For example,an electron with momentum perpen-dicular to a uniform background magneticﬁeld moves in a circle.Suppose in the same observer frame we instanta-neously increase the magnitude of the electron momentum without changing its direction,causing the electron to move in a circle of larger radius.This͑instantaneous͒particle boost676255DON COLLADAY AND V.ALAN KOSTELECKY´leaves the backgroundﬁeld unaffected.However,if insteadan observer boost perpendicular to the magneticﬁeld is ap-plied,the electron no longer moves in a circle.This is viewed in the new inertial frame as an EϫB drift caused bythe presence of an electricﬁeld.In this example,the back-ground magneticﬁeld transforms into a different electromag-neticﬁeld under observer boosts but͑by deﬁnition͒is un-changed by particle boosts,in analogy to the transformation of a␮and b␮in the CPT-violating model.From the viewpoint of this example,the unconventional aspect of the CPT-violating model is merely that the con-stantﬁelds a␮and b␮are a global feature of the model.Theycannot be regarded as arising from localized experimentalconditions,which would cause them to transform under par-ticle Lorentz transformations as four-vectors rather than as scalars.The behavior of a␮and b␮as backgroundﬁelds andhence as scalars under particle Lorentz transformations is aconsequence of their origin as nonzero expectation values ofLorentz tensors in the underlying theory.These Lorentz-tensor expectations break those parts of the particle Lorentzgroup that cannot be implemented as unitary transformationson the vacuum.This is in parallel with other situations in-volving spontaneous symmetry breaking,such as ones com-monly encountered in the treatment of internal symmetries.The preservation of observer Lorentz symmetry is an im-portant feature of the model.It is a consequence of observerLorentz invariance of the underlying fundamental theory.This symmetry is unaffected by the appearance of tensorexpectation values by virtue of its implementation via coor-dinate transformations.As an illustration of its use in theeffective model,we show that it permits a further classiﬁca-tion of types of CPT-violating term according to the ob-server Lorentz properties of a␮and b␮.Thus,for example, if b␮is future timelike in one inertial frame,it must be futuretimelike in all frames.This implies that a class of inertial frames can be found in which b␮ϭb(1,0,0,0),where calcu-lations are potentially simpliﬁed.A similar argument for the lightlike or spacelike cases shows that the CPT-violating physics of the four components of b␮can in each case bereduced to knowledge of its Lorentz type and a single num-ber specifying its magnitude.Inertial frames within this ideal class are determined by the little group of b␮,which can in turn be used to simplify͑partially͒the form of a␮.The reader is cautioned that the class of inertial framesselected in this way may be distinct from experimentallyrelevant inertial frames such as,for example,those deﬁnedusing the microwave background radiation and interpretingthe dipole component in terms of the motion of the Earth.The point is that,given an inertial frame,the process ofspontaneous Lorentz violation in the underlying theory is assumed to produce some values of a␮and b␮.In this spe-ciﬁc inertial frame,there is no reason a priori why these values should take the ideal form described above.One is merely assured of the existence of some frame in which the ideal form can be attained.The current J␭␮␯for particle Lorentz transformationstakes the usual form when expressed in terms of the energy-momentum tensor:J␭␮␯ϭx[␮⌰␭␯]ϩ14␺¯͕␥␭,␴␮␯͖␺.͑11͒This current is conserved at the level of the underlying theory with spontaneous symmetry breaking,but in the ef-fective low-energy theory where the spontaneous breaking appears as an explicit symmetry violation the conservation property is destroyed.In the latter case,the corresponding Lorentz charges M␮␯obeydM␮␯dtϭϪa[␮J␯]Ϫb[␮J5␯].͑12͒Given explicit values of a␮and b␮in some inertial frame, Eq.͑12͒can be used directly to determine which Lorentz symmetries are violated.Note that if either a␮or b␮van-ishes,the Lorentz group is broken to the little group of the nonzero four-vector.This means that the largest Lorentz-symmetry subgroup that can remain as an invariance of the model Lagrangian͑5͒is SO͑3͒,E͑2͒,or SO͑2,1͒.Since a␮and b␮represent two four-vectors in four-dimensional space-time,they can deﬁne a two-dimensional plane.Transforma-tions involving the two orthogonal dimensions have no effect on this plane.This means that the smallest Lorentz-symmetry subgroup that can remain is a compact or noncom-pact U͑1͒.In a realistic low-energy effective theory,CPT-violating terms would break the particle Lorentz group in a manner related to the breaking given by Eq.͑12͒.Since no zeroth-order CPT violation has been observed in experiments, CPT-violating effects in the string scenario are expected to be suppressed by at least one power of the Planck mass rela-tive to the scale of the effective theory.However,the inter-esting and involved issue of exactly how small the magni-tudes of a␮and b␮͑or their equivalents in a realistic model͒must be to satisfy current experimental constraints lies be-yond the scope of the present work.We conﬁne our remarks here to noting that the partial breaking of particle Lorentz invariance discussed above generates an effective boost de-pendence in the CPT-breaking parameters.This could pro-vide a deﬁnite experimental signature for our framework if CPT violation were detected at some future date.C.Field redeﬁnitionsFor the discussions in the previous subsections,we adopted a practical approach to the deﬁnition of CPT and Lorentz transformations.It involves treating C,P,T and Lorentz properties of␺as being deﬁned via the free-ﬁeld theory L0and subsequently using them to establish the sym-metry properties of LЈ.This approach requires caution,how-ever,because in principle alternative deﬁnitions of the sym-metry transformations could exist that would leave the full theory L invariant.Considerﬁrst an apparently CPT-and Lorentz-violating model formed with a␮only,deﬁned in a given inertial frame by the LagrangianL͓␺͔ϭL0͓␺͔ϪL aЈ͓␺͔.͑13͒Introducing in this frame aﬁeld redeﬁnition of␺by a spacetime-dependent phase,␹ϭexp͑ia•x͒␺,͑14͒556763CPT VIOLATION AND THE STANDARD MODELthe Lagrangian expressed in terms of the newﬁeld is L͓␺ϭexp(Ϫia•x)␹͔ϵL0͓␹͔.This shows that the model is equivalent to a conventional free Dirac theory,in which there is no CPT or Lorentz breaking,and thereby provides an example of redeﬁning symmetry transformations to main-tain invariance͓24͔.The connection between the Poincare´generators in the two forms of the theory can be found explicitly by substitut-ing␺ϭ␺͓␹͔in the Poincare´generators for L͓␺͔and ex-tracting the combinations needed to reproduce the usual Poincare´generators for L0͓␹͔.Weﬁnd that the charge and chiral currents j␮and j5␮take the same functional forms in both theories but that the form of the canonical energy-momentum tensor changes,⌰␮␯ϭ12i␹¯␥␮ץJ␯␹ϩa␯␹¯␥␮␹,͑15͒producing a corresponding change in the Lorentz current J␭␮␯.This means that in the original theory L͓␺͔we could introduce modiﬁed Poincare´currents⌰˜␮␯and J˜␭␮␯that have corresponding conserved charges generating an unbro-ken Poincare´algebra.These currents are given as functionals of␺by⌰˜␮␯ϭ⌰␮␯Ϫa␯j␮,J˜␭␮␯ϭJ␭␮␯Ϫx[␮a␯]j␭.͑16͒The existence of this connection between the two theories depends critically on the existence of the conserved current j␮.In the model͑5͒with both a␮and b␮terms,the compo-nent L aЈcan be eliminated by aﬁeld redeﬁnition as before but there is no similar transformation removing L bЈbecauseconservation of the chiral current j5␮is violated by the mass. In the massless limit of this model the chiral current is con-served,and we can eliminate both a␮and b␮via theﬁeld redeﬁnition␹ϭexp͑ia•xϪib•xy5͒␺.͑17͒For the situation with m 0,however,this redeﬁnition would introduce spacetime-dependent mass parameters.The term L aЈin Eq.͑3͒is reminiscent of a local U͑1͒coupling,although there is no local U͑1͒invariance in the theory͑5͒.It is natural and relevant to our later consider-ations of the standard model to ask how the above discussion ofﬁeld redeﬁnitions is affected if the U͑1͒invariance of the original theory is gauged.Then,the term L aЈhas the same form as a coupling to a constant background electromagnetic potential.At the classical level,this would be expected to have no effect since it is pure gauge.However,a conven-tional quantum-ﬁeld gauge transformation involving both␺and the electromagnetic potential A␮cannot eliminate a␮, since the theory is invariant under such transformations.In-stead,the electromagneticﬁeld can be taken as the sum of a classical c-number backgroundﬁeld A␮and a quantumﬁeld A␮,whereupon a␮can be regarded as contributing to an effective A␮.Conventional classical gauge transformations can be performed on the c-number potential A␮,while leav-ing the quantumﬁelds␺and A␮unaffected.This changes the Lagrangian but should not change the physics.In fact, the resulting gauge-transformed Lagrangian is unitarily equivalent to the original one under aﬁeld redeﬁnition on␺of the form discussed above for the ungauged model.To summarize,in the gauged theory the CPT-breaking term L aЈcan be interpreted as a background gauge choice and eliminated via aﬁeld redeﬁnition as in the ungauged case. We note in passing that related issues arise for certain non-linear gauge choices͓25͔and in the context of efforts to interpret the photon as a Nambu-Goldstone boson arising from͑unphysical͒spontaneous Lorentz breaking͓26–32͔.In typical models of the latter type,a four-vector bilinear con-densate͗␺¯␥␮␺͘plays a role having some similarities to that of a␮.The model͑5͒involves only a single fermionﬁeld.All CPT-violating effects can also be removed from certain theories describing more than one fermionﬁeld in which each fermion has a term of the form L aЈ.For example,this is possible if there is no fermion mixing and each such CPT-violating term involves the same value of a␮,or if the fermions have no interactions or mixings that acquire spacetime-dependence upon performing theﬁeld redeﬁni-tions.However,in generic multifermion theories with CPT violation involving fermion-bilinear terms,it is impossible to eliminate all CPT-breaking effects throughﬁeld redeﬁni-tions.Nonetheless,since Lagrangian terms that spontane-ously break CPT necessarily involve paired fermionﬁelds, at least one of the quantities a␮can be removed.This means that only differences between values of a␮are observable. Examples appear in the context of the CPT-violating exten-sion of the standard model discussed in Sec.V.III.RELATIVISTIC QUANTUM MECHANICS In this section,we discuss some aspects of relativistic quantum mechanics based on Eq.͑6͒,with␺regarded as a four-component wave function.The results obtained provide further insight into the nature of the CPT-violating terms and are precursors to the quantumﬁeld theory.The analo-gous treatment in the context of the standard model involves several fermionﬁelds,for which CPT-violating terms of the form L aЈcannot be altogether eliminated.We therefore ex-plicitly include the quantity a␮in the following analysis, even though it could be eliminated by aﬁeld redeﬁnition for the simple one-fermion case.In fact,the reinterpretation of negative-energy solutions causes the explicit effects of a␮to be more involved than might otherwise be expected.The modiﬁed Dirac equation͑6͒can be solved by assum-ing the usual plane-wave dependence,␺͑x͒ϭeϪi␭␮x␮w͑␭ជ͒.͑18͒In this equation,w(␭ជ)is a four-component spinor satisfying ͑␭␮␥␮Ϫa␮␥␮Ϫb␮␥5␥␮Ϫm͒w͑␭ជ͒ϭ0.͑19͒For a nontrivial solution to exist,the determinant of the ma-trix acting on w(␭ជ)in this equation must vanish.This means that␭␮ϵ(␭0,␭ជ),where͓33͔␭0ϭ␭0(␭ជ),must satisfy the requirement͓͑␭Ϫa͒2Ϫb2Ϫm2͔2ϩ4b2͑␭Ϫa͒2Ϫ4͓b␮͑␭␮Ϫa␮͔͒2ϭ0.͑20͒676455DON COLLADAY AND V.ALAN KOSTELECKY´。

写一篇如何解决能源短缺问题的英文作文

Addressing Energy Shortages: A Multifaceted ApproachIn the face of mounting global challenges, energy shortages have emerged as a pressing concern that demands immediate attention and innovative solutions. The consequences of inadequate energy supplies extend far and wide, impacting economic growth, social welfare, and environmental sustainability. To effectively tackle this issue, a multifaceted approach is necessary, encompassing diversification of energy sources, promotion of energy efficiency, investment in renewable technologies, and fostering international cooperation.Firstly, diversifying our energy mix is crucial. Reliance on a single or few energy sources, particularly fossil fuels, exacerbates vulnerability to supply disruptions and price volatility. By exploring and developing alternative energy resources such as nuclear, solar, wind, and hydroelectric power, we can create a more resilient energy system. This diversification not only reduces the risk of shortages but also aligns with the goal of transitioning to a low-carbon economy.Secondly, promoting energy efficiency is a high-impact strategy. Enhancing the efficiency of energy use across sectors—from industrial processes to household appliances—can significantly reduce demand and alleviate pressure on energy supplies. Governments can play a pivotal role by implementing policies that encourage energy-efficient practices and technologies, such as providing subsidies for green building projects or setting mandatory efficiency standards for products.Thirdly, investing in renewable energy technologies is paramount. Renewables offer a sustainable and scalable solution to energy shortages. Advancements in solar panels, wind turbines, and battery storage technologies have made renewable energy more competitive and accessible. Governments and private sectors must collaborate to scale up research and development, facilitate financing mechanisms, and streamline regulatory processes to accelerate the deployment of renewable energy projects.Furthermore, fostering international cooperation is vital. Energy shortages are a global challenge that requires collective action. Countries can collaborate on cross-border energy infrastructure projects, share best practices in energy management, and coordinate efforts to mitigate climate change, which indirectly contributes to energy security by promoting sustainable energy sources.Lastly, public awareness and engagement are essential components of any comprehensive strategy. Educating citizens about energy conservation, the benefits of renewable energy, and the importance of energy security can inspire individual actions that, when multiplied across populations, lead to substantial impacts.In conclusion, addressing energy shortages necessitates a comprehensive andintegrated approach that combines diversification of energy sources, promotion of energy efficiency, investment in renewable technologies, international cooperation, and public engagement. By pursuing these strategies in concert, we can pave the way for a more secure, sustainable, and prosperous energy future.。

林菲尔·拜肯斯朗电动液

SAM400 & 650 PERKINS DIESEL ENGINE DRIVENIM568 April, 1997Mar ‘95Mar ‘95Mar.‘93for selecting a QUALITY product by Lincoln Electric.We want you to take pride in operating this Lincoln Electric Company product •••as much pride as we have in bringing this product to you!Read this Operators Manual completely before attempting to use this equipment.Save this manual and keep it handy for quick reference.Pay particular attention to the safety instructions we have provided for your protection.The level of seriousness to be applied to each is explained below:vv(1)Consult applicable federal, state and local laws regardingspecific requirements for use on public highways.SPEED CONTROL LEVERManually allows the engine to run at its high idle speed controlled by the governor or at the factory set low idle speed.When welding or using auxiliary power the speed control lever must be in the “RUN”position.T o reduce the engine to low idle speed when not welding or not using auxiliary power place the speed control lever in the “IDLE”position notch.ENGINE TEMPERATURE GAUGEDisplays the coolant temperature in the engine block. OIL PRESSURE GAUGEDisplays the oil pressure to the engine.When the engine starts running, watch for the oil pressure to build up.If no pressure shows within 30 seconds, stop the engine and consult the engine instruction manual. BATTERY CHARGING AMMETERDisplays the current going from the charging alternator into the batteries.It is normal for charging current to be high (above 15 amps) after starting or when the batter-ies are ‘low’on charge.ENGINE HOUR METER(Factory Installed Optional Feature)The optional engine hour meter records the total run-ning time on the engine in hours.It can be used to keep a record of maintenance on the engine and or welder. ENGINE PROTECTION SYSTEMThe engine protection system shuts down the engine under high coolant temperature or low oil pressure conditions by allowing the fuel solenoid valve to close.place.3.Remove the two screws on the top end of the wirefeeder nameplate.4.Position the “Portable Field Control”mounting slotsover these holes and replace the screws.5.Route the leads with the LN-5 or LN-6 control cableback to the power source.MOUNTING ON LN-71.Remove the top screws on the side of the LN-7 con-trol box cover.(This is the left side when facing the nameplate).2.Position the “Portable Field Control”on the side ofthe control box with the mounting slots over these holes and replace the screws.3.Route the leads with the LN-7 control cable back tothe power source.OUTPUT STUDSWith the Engine OFF connect the work cable to the “T o Work”stud.A.For Stick Electrode Welding1.Connect the electrode cable to the “Stick”studand the work cable to the “T o Work”stud.Connect the “T AP”lead in the SAM650 to theappropriate stud to adjust current and the arccharacteristics as described under “Currentand Voltage Controls.”2.Install the “Portable Field Control”.B.Automatic or Semiautomatic WeldingFor all automatic welding processes, connect the welding power cable from the wire feeder to the “Connect to Auto.Equipment”stud.Connect the “T AP”lead in the SAM650 to the appropriate stud to adjust current and the arc characteristics as described under “Current and Voltage Controls.”1.LN-7, LN-8, LN-9, NA-3, NA-5, LT-7 and LT-56 Wire Feeders.a.Make the connections exactly as speci-fied on the connection wiring diagramincluded in the wire feeder InstructionManual.b.Install the “Portable Field Control”whenusing an LN-7.CURRENT AND VOLTAGE CONTROLS Constant Voltage WeldingThe SAM-400 “Current Control”is NOT in the circuit when the ‘Electrode Polarity’switch is set for constant voltage welding.Set the open circuit voltage (OCV) needed for the par-ticular application with the “Constant Voltage Control”located to the left of the nameplate.Adjust the final welding voltage with either the wire feeder voltage con-trol or the “Portable Field Control”.Set the welding cur-rent with “Amps”or “Wire Feed Speed”control on the wire feeder.Low Range Feature (SAM400 K1279-1 only) --Extends the output voltage range of the SAM400 welder down to 12 volts for constant voltage welding. The maximum output current is not to exceed the rat-ing of the machine.The Low Range Feature provides a two-position manual switch which allows the operator to set his machine for normal welding or for low voltage welding.Factory installed only.On the SAM650 connect the “T ap”lead inside the machine to the appropriate “Innershield”stud for”Min. (Flat) Slope.”“Med.Slope”or “Max.Slope”.Low voltage (below 20 volts) low current welding often requires “Max.Slope”to adjust the weld metal droplet size for minimum spatter and to control puddle fluidity and bead shape.Innershield and other spray transfer type processes generally operate with “Med.Slope”.A Hot Start circuit on all models operates automatical-ly whenever the toggle switch is set on “Constant Voltage.”It increases the open circuit voltage by sev-eral volts until the arc is established -- then the voltage automatically drops to normal welding voltage.When the wire feeder is started before the arc is started, the voltmeter indicates a voltage several volts higher than welding voltage.T o read actual welding voltage, the arc must be established.Constant Voltage Welding With Variable Inductance Control:SAM-400 Only.Variable inductance or slope control is usually desir-able for low voltage (below 20 volts) applications and is sometimes useful in other constant voltage jobs.To introduce this control into the circuit, set the “Electrode Polarity”switch to “Variable Voltage”and the toggle switch to “Constant Voltage”.Then the “Current Control”acts as the variable inductance control. Normally this control must be kept within the 8 to 1 o’clock range.To Set The Controls -- Stick Weldinga.Make the coarse setting of welding heat with theSAM400 “Current Control”or the SAM650“T ap’”lead.b.Adjust for the desired arc characteristics with the“Variable Voltage Control”.For a soft arc desired for most welding keep this control between 7 and High.For a more digging arc, set it lower.c.If remote control is NOT desired leave the“Portable Field Control”on “High”.For remote con-trol, leave the “Variable Voltage Control”near “High”and make the adjustments described in paragraph “b”above with the “Portable Field Control”.Remember, increasing either the “Variable Voltage Control”or “Portable Field Control”setting also increases the current.To Set The Controls -- Submerged Arca.The open circuit voltage (OCV) is generally notcritical in submerged arc welding.Therefore, the “Variable Voltage Control”can usually be left between 7 and “High”-- no future adjustments are needed.b.Set SAM400 “Current Control”so the calibrationon the higher scale is a little above the current desired.Set the SAM650 “T ap”lead to the stud with the lowest current range that still provides the desired current.c.Make the final current adjustment with either thewire feeder current control or the “Portable Field Control”.Set the arc voltage with the wire feeder control.Consult the following illustrations for examples of how to set the machine.STARTING WELDERS WITH DEAD BATTERIES Array DO NOT attempt to start a SAM engine driven welder by driving the welding generator as a starter motor using the output of another welder.In addition to the possibility of damaging the machines, starting a SAM engine welder without using its starting circuit elimi-nates the operation of the flashing circuit.This can cause the generator to fail to produce any output. AUXILIARY POWERAn alternator generates 2 KVA of 120/240 volt 60 Hertz AC power.It is available either from #31 and #32 on the terminal strip or from the receptacles on the Control Panel.Be careful not to overload this circuit. The auxiliary power receptacle should only be used with three wire grounded type plugs or approved dou-ble insulated tools with two wire plugs.The alternator is protected by thermostats and fuses. DUTY CYCLEDuty cycle is based on a ten minute period and opera-tion in an ambient temperature of 104°F(40°C).The SAM400 is NEMA rated at 60% duty cycle.The SAM650 is NEMA rated at 80% duty cycle.Duty cycle is based on a ten minute period.Therefore, a 60% duty cycle welder can be operated at nameplate rated out-put for 6 minutes (8 minutes for 80% duty cycle) out of every 10 minute period without overheating.The auxiliary power can be used continuously (100% duty cycle) within its rated current capacities.STARTING INSTRUCTIONSBe sure all Pre-Operation Maintenance has been per-formed.(See Installation Section of this manual.)T o start the engine, set the speed control lever in the “RUN”position.Place ignition toggle switch in the “ON”position.Push in the engine protection system reset button (if so equipped).Engage the starter button. When the engine starts running, observe the oil pres-sure.If no pressure shows within 30 seconds, stop the engine and consult the engine operating manual.T o stop the engine, place the ignition toggle switch in the “OFF”position.When an engine is started for the first time, some of the oil will be needed to fill the passages of the lubricatingsystem.Therefore, on initial starting, run the engine forK799 Hi-Freq™-Provides high frequency plus a gas valve for TIG welding.A water valve is available as an option.Requires 115 volt AC input.Cannot be used with optional meters connected, or in constant voltage mode.(Limited to 250A - 60% Duty Cycle).K802-D Power Plug Kit -For SAM welders with stan-dard 2KVA of AC auxiliary power.Kit includes male plugs for each auxiliary receptacle.K805-1 Ether Start Kit -Injects ether for starting aid. Recommended only when engines are frequently started at temperatures under 10°F (-12°C).Ether cylinder is not included.K767-1 Undercarriage -A 4-wheel steerable under-carriage for in-plant and yard towing1with E78-14 load range (B) tubeless tires.Mounts directly to welder base.1For highway use, consult applicable federal, state and local laws regarding possible requirements for brakes, lights, fenders, etc.Linc-Thaw™- Includes meter and fuse to protect the welder when thawing frozen water pipes.(L2964-[ ] Specify SAM400 or SAM650)K704(SAM400 only) Standard Accessory Kit -Includes electrode and work cables, headshield, work clamp and electrode holder.K865(SAM400 only) Engine Hour Meter Kit -(Standard on K1279-1).Keeps track of how long engine has been eful for following recom-mended maintenance schedules on machine.SAM400 only:Inspect the oil bath air filter daily - more often in dusty conditions.When necessary clean and fill the oil bath. The filter should never be removed while the engine is running.PERIODIC MAINTENANCE1.Blow out the welder and controls with an air hose atleast once every two months.In particularly dirty locations, this cleaning may be necessary once a e low pressure air to avoid driving dirt into the insulation.2.The SAM400 current control reactor brushes areself-lubricating and should not be greased.Keep the contacts clean.This control should be moved from maximum to minimum daily to prevent the controls from sticking.3.See the engine Instruction Manual for periodicengine maintenance information.Change the crankcase oil at regular intervals using the proper grade of oil as recommended in the engine operat-ing manual.Change the oil filter in accordance with the instructions in the engine operating manual.When the filter is changed add one quart of oil to the crankcase to replace the oil held in the filter dur-ing operation.4.Belts tend to loosen after the first 30 or 40 hours ofoperation.Check the cooling fan belt and tighten if necessary.DO NOT OVER TIGHTEN.BEARING MAINTENANCEThis welder is equipped with a double-shielded ball bearing having sufficient grease to last indefinitely under normal service.Where the welder is used con-stantly or in excessively dirty locations, it may be nec-essary to add one-half ounce of grease per year.A pad of grease one inch wide, one inch long and one inch high weighs approximately one-half ounce.Over greasing is far worse than insufficient greasing. When greasing the bearings, keep all dirt out of the area.Wipe the fittings completely clean and use clean equipment.More bearing failures are caused by dirt introduced during greasing than from insufficient grease.Arcing or excessive exciter brush wear indicates a pos-sible misaligned shaft.Have an authorized Field Service Shop check and realign the shaft. COOLING SYSTEMThe SAM welders are equipped with a pressure radia-tor.Keep the radiator cap tight to prevent loss of coolant.Clean and flush the cooling system periodi-cally to prevent clogging the passage and overheating the engine.When antifreeze is needed, always use the permanent type.CONTACTOR MAINTENANCEWhere the output contactor is operated frequently when tacking or making short welds, turn the engine off and inspect the contactor every three months:1.be sure the mating surfaces of silver contacts arenot worn and all make contact at approximately the same time.2.Make sure the springs and holders are not brokenor out of adjustment.Approximate spring com-pression after making contact is 1/8”.Less than 1/16”compression indicates worn contacts that should be replaced.3.Make sure the moving contact or other movingparts are not binding.4.Check interlock contacts and springs.Be suremounting screws are tight.NOTE A:If at any time either of the Control (PC) boards is replaced, follow the calibration procedure outlined later in this sec-tion under “Control P.C.Board Calibration Procedure”.The open circuit voltage will be out of range if trimmers are not properly set.If both trimmers are set at minimum, the machine might lose excitation.NOTE B:When making continuity checks, use the 1K (X1000) or next higher range.NOTE C:Do not replace PC boards without following outlined procedure for indicated trouble -- damage may result due to other defective parts.DC on SAM400 machines or 45±1 volts forSAM650 machines.Recheck to make surereadings fall within limits.T rimmer #4 set-ting is dependent on T rimmer #3.B.Constant Voltage1.Place toggle switch in constant voltageposition.2.T urn constant voltage rheostat and portablefield control to high.3.Set T rimmer #1 so that OCV is 60±1 voltsDC on SAM400 machines or 68±1 volts forSAM650 machines.4.T urn constant voltage rheostat and portablefield control to low.5.Set T rimmer #2 so that OCV is 21±0.5 voltsDC on SAM400 machines or 22±0.5 voltsfor SAM650 machines.Recheck to makesure readings fall within limits.T rimmer #2setting is dependent on T rimmer #1.N O T E :T h i s d i a g r a m i s f o r r e f e r e n c e o n l y .I t m a y n o t b e a c c u r a t e f o r a l l m a c h i n e s c o v e r e d b y t h i s m a n u a l.T h e s p e c i f i c d i a g r a m f o r a p a r t i c u l a r c o d e i s p a s t e d i n s i d e t h e m a c h i n e o n o n e o f t h e e n c l o s u r e p a n e l s .Now Available...12th EditionThe Procedure Handbook of Arc WeldingWith over 500,000 copies of previous editions published since 1933, the Procedure Handbook is considered by many to be the “Bible”of the arc welding industry.This printing will go fast so don’t delay.Place your order now using the coupon below.The hardbound book contains over 750 pages of welding infor-mation, techniques and procedures.Much of this material has never been included in any other book.A must for all welders, supervisors, engineers and designers.Many welding instructors will want to use the book as a reference for all students by taking advantage of the low quan-tity discount prices which include shipping by 4th class parcel post.$15.00postage paid U.S.A.MainlandHow To Read Shop DrawingsThe book contains the latest information and application data on the American Welding Society Standard Welding Symbols.Detailed discussion tells how engineers and drafts-men use the “short-cut”language of symbols to pass on assembly and welding information to shop personnel.Practical exercises and examples develop the reader’s ability to visualize mechanically drawn objects as they will appear in their assembled form.187 pages with more than 100 illustrations.Size 8-1/2”x 11”Durable, cloth-covered board binding.$4.50postage paid U.S.A.MainlandNew Lessons in Arc WeldingLessons, simply written, cover manipulatory techniques;machine and electrode characteristics;related subjects, such as distortion;and supplemental information on arc welding applications, speeds and costs.Practice materials, exercises,questions and answers are suggested for each lesson.528 pages, well illustrated, 6”x 9”size, bound in simulated,gold embossed leather.$5.00postage paid U.S.A.MainlandNeed Welding Training?The Lincoln Electric Company operates the oldest and most respected Arc Welding School in the United States at its corporate headquarters in Cleveland, Ohio.Over 100,000students have graduated.Tuition is low and the training is “hands on”For details write:Lincoln Welding School 22801 St.Clair Ave.Cleveland, Ohio 44117-1199.and ask for bulletin ED-80 or call 216-383-2259 and ask for the Welding School Registrar.Lincoln Welding SchoolBASIC COURSE $700.005 weeks of fundamentalsThere is a 10%discount on all orders of $50.00 or more for shipment at one time to one location.Orders of $50 or less before discount or orders outside of North America must be prepaid with charge, check or money order in U.S. Funds Only.Prices include shipment by 4th Class Book Rate for U.S.A. Mainland Only.Please allow up to 4 weeks for delivery.UPS Shipping for North America Only.All prepaid orders that request UPS shipment please add:$5.00For order value up to $49.99$10.00For order value between $50.00 & $99.99$15.00For order value between $100.00 & $149.00For North America invoiced orders over $50.00 & credit card orders, if UPS is requested, it will be invoiced or charged to you at cost.Outside U.S.A. Mainland order must be prepaid in U.S. Funds.Please add $2.00 per book for surface mail or $15.00 per book for air parcel post shipment.METHOD OF PAYMENT:(Sorry, No C.O.D.Orders)CHECK ONE:Name:_______________________________________________Address:_______________________________________________Ohio 44117-1199216-361-5901.JapaneseChineseKoreanArabicREAD AND UNDERSTAND THE MANUFACTURER’S INSTRUCTION FOR THIS EQUIPMENT AND THE CONSUMABLES TO BE USED AND FOLLOW YOUR EMPLOYER’S SAFETY PRACTICES.SE RECOMIENDA LEER Y ENTENDER LAS INSTRUCCIONES DEL FABRICANTE PARA EL USO DE ESTE EQUIPO Y LOS CONSUMIBLES QUE VA A UTILIZAR, SIGA LAS MEDIDAS DE SEGURIDAD DE SU SUPERVISOR.LISEZ ET COMPRENEZ LES INSTRUCTIONS DU FABRICANT EN CE QUI REGARDE CET EQUIPMENT ET LES PRODUITS A ETRE EMPLOYES ET SUIVEZ LES PROCEDURES DE SECURITE DE VOTRE EMPLOYEUR.LESEN SIE UND BEFOLGEN SIE DIE BETRIEBSANLEITUNG DER ANLAGE UND DEN ELEKTRODENEINSATZ DES HER-STELLERS. DIE UNFALLVERHÜTUNGSVORSCHRIFTEN DES ARBEITGEBERS SIND EBENFALLS ZU BEACHTEN.JapaneseChineseKoreanArabicLEIA E COMPREENDA AS INSTRUÇÕES DO FABRICANTE PARA ESTE EQUIPAMENTO E AS PARTES DE USO, E SIGA AS PRÁTICAS DE SEGURANÇA DO EMPREGADOR.。

小学上册第四次英语第4单元自测题

小学上册英语第4单元自测题英语试题一、综合题(本题有100小题，每小题1分，共100分.每小题不选、错误，均不给分)1.The chemical symbol for cadmium is __________.2.The Earth's crust is continuously changing due to ______.3.The ________ (地方美食) represents our culture.4.n Wall was a symbol of the __________ (冷战). The Berl5.An endothermic reaction absorbs ______.6.My favorite fruit is ___. (banana)7.My dad is a ________.8.My friend is a _____ (记者) who covers important stories.9.The capital of Cyprus is __________.10.What is the main ingredient in mashed potatoes?A. RiceB. PotatoesC. CornD. CarrotsB11.I can _____ (dance/sing) very well.12. A chemical reaction that produces gas can be identified by the formation of _____ bubbles.13.The capital of Kazakhstan is __________.14.What is the opposite of 'sweet'?A. SourB. BitterC. SaltyD. SpicyA15.What is the capital of Finland?A. HelsinkiB. TallinnC. OsloD. Stockholmpounds can be classified as ionic or ______.17.My dad loves __________ (历史).18.What is the term for a baby elephant?A. CubB. CalfC. PupD. KidB Calf19.My pet _____ (鹦鹉) can talk.20.environmental education) promotes awareness and action. The ____21.Which animal is known for its trunk?A. LionB. ElephantC. TigerD. BearB Elephant22.What is the capital of England?英国的首都是什么？A. ParisB. LondonC. BerlinD. MadridB23.The _____ is the distance between two points in space.24.What is the process of water vapor turning into liquid called?A. EvaporationB. PrecipitationC. CondensationD. SublimationC25. A _____ (自然) habitat supports diverse plants.26.In a chemical reaction, the reactants are on the ______ side of the equation.27.My mom enjoys __________ (旅行) to new places.28.The garden has many _____ (flowers/plants).29.We celebrate ______ (Christmas) in December.30.I love _____ (花) in the spring.31.My sister is a __________ (舞者).32.What is the name of the famous clock tower in London?A. Big BenB. Tower BridgeC. London EyeD. Buckingham PalaceA33.The _______ of a wave can be affected by the medium it travels through.34.The hawk soars high in the _______ (天空).35.The alligator swims in the _____.36.Metals are typically ______ conductors of electricity.37.What is the main source of energy for the Earth?A. WindB. WaterC. SunD. CoalC38.We can see _______ in the rainforest.39.What is the color of the sun?A. BlueB. YellowC. WhiteD. RedB40.The ________ is a small animal that loves to burrow.41. A ______ (生态友好的方法) can lead to better practices.42.The ancient Romans spoke ______ (拉丁语).43.I want to be a ________ when I grow up.44.What is the sound a dog makes?A. MeowB. RoarC. BarkD. MooC45. A __________ is a mixture that can be separated by centrifugation.46. A _______ is a type of chemical reaction that consumes energy.47.What do you call a story that is made up?A. Non-fictionB. BiographyC. FictionD. HistoryC48.What is the opposite of empty?A. FullB. LightC. HeavyD. DarkA49.What is the name of the famous detective known for solving mysteries?A. Hercule PoirotB. Sherlock HolmesC. Miss MarpleD. Sam Spade50.What is the capital of Argentina?A. SantiagoB. Buenos AiresC. LimaD. BogotáB51.My toy ____ is always ready for adventure! (玩具名称)52.How many players are on a baseball team?A. 9B. 10C. 11D. 1253.I enjoy ________ ( gardening) in my free time.54.What kind of animal is an octopus?A. MammalB. FishC. ReptileD. MolluskD55.Which shape has four equal sides?A. TriangleB. CircleC. SquareD. Rectangle56.My uncle loves to __________ (分享) his travel stories.57. A __________ is a low-lying coastal area.58.Eclipses occur due to the alignment of the sun, moon, and ______.59.I love to explore nature. One of my favorite places to hike is __________.60. A ____(team-building exercise) fosters collaboration.61.The _____ (狼) is a symbol of wilderness.62.I have a blue ________.63.The _______ (海龟) swims in the ocean.64. A _______ can measure the temperature of a gas.65. A __________ is a city that is not the capital but is important for trade.66.She has a nice ________.67.What is the name of the famous ancient city in Greece?A. AthensB. MycenaeC. DelphiD. All of the above68.What is the capital of the Seychelles?A. VictoriaB. MahéC. PraslinD. La Digue69.Some plants can grow in _______ conditions.70. A ______ is a natural feature that can influence weather.71.I enjoy exploring new ______ (地方), especially historical sites.72.The chemical formula for isobutyric acid is ______.73.In nature, every plant has its own __________ (角色).74.The ______ (自然) world is full of wonders related to plants.75.My dad _____ the car every Saturday. (washes)76.What is the name of the common game played with marbles?A. JacksB. MarblesC. Snakes and LaddersD. ChessB77.The chemical formula for glycine is ______.78.The chemical formula for ferric oxide is ______.79.The ________ was a famous philosopher who influenced Western thought.80.I love building with my ________ (乐高) sets every weekend.81.What do we call the changes in the weather over a long period?A. ClimateB. WeatherC. SeasonD. Forecast82.Where does Santa Claus live?A. North PoleB. South PoleC. AustraliaD. New York83.The ________ (花瓣) are often colorful.84.I like to help my ______ in the kitchen. (我喜欢在厨房帮助我的______。

丁基锂裂解四氢呋喃

9
Reactivity of O-heterocycles – Oxetane opening
• On the other hand, in the presence of a base, however, ring opening of oxetane is extremely slow. • Oxetane undergoes hydrolysis 3-orders of magnitude slower than oxirane under alkaline conditions. The plausible explanation could be the following: in the case of 3-membered oxirane more strain is released in the transition state, which leads to a lower activation energy than in 4-membered rings. • This reactivity difference towards nucleophiles means that ring-opening reactions of oxetanes often require the use of strong Brønsted or Lewis acids and/or higher reaction temperatures.
• The inherent strain of 4-membered ring and the leaving-ability of O-atom leads to opening reactions. • Oxetane undergoes a very fast hydrolysis with mineral acids (e.g. H2SO4) similarly to the oxirane. • Synthetically useful is the selective opening of the spiro-oxetane with HBr to the 1,3-bromoalcohol.

g-C3N4

第42卷第10期2023年10月硅㊀酸㊀盐㊀通㊀报BULLETIN OF THE CHINESE CERAMIC SOCIETY Vol.42㊀No.10October,2023g-C 3N 4/Ag 基二元复合光催化剂降解环境污染物的研究进展柏林洋1,蔡照胜2(1.江苏旅游职业学院,扬州㊀225000;2.盐城工学院化学化工学院,盐城㊀224051)摘要:光催化技术在太阳能资源利用方面呈现出良好的应用前景,已受到世界各国的广泛关注㊂g-C 3N 4是一种二维结构的非金属聚合物型半导体材料,具有合成简单㊁成本低㊁化学性质稳定㊁无毒等特点,在环境修复和能量转化方面应用潜力较大㊂但g-C 3N 4存在对可见光吸收能力差㊁比表面积小和光生载流子复合速率高等缺点,限制了其实际应用㊂构筑异质结光催化剂是提高光催化效率的有效途径之一㊂基于Ag 基材料的特点,前人对g-C 3N 4/Ag 基二元复合光催化剂进行了大量研究,并取得显著成果㊂本文总结了近年来AgX(X =Cl,Br,I)/g-C 3N 4㊁Ag 3PO 4/g-C 3N 4㊁Ag 2CO 3/g-C 3N 4㊁Ag 3VO 4/g-C 3N 4㊁Ag 2CrO 4/g-C 3N 4㊁Ag 2O /g-C 3N 4和Ag 2MoO 4/g-C 3N 4复合光催化剂降解环境污染物的研究进展,并评述了g-C 3N 4/Ag 基二元复合光催化剂目前面临的主要挑战,展望了其未来发展趋势㊂关键词:g-C 3N 4;Ag 基材料;二元复合光催化剂;光催化性能;环境污染物中图分类号:TQ426㊀㊀文献标志码:A ㊀㊀文章编号:1001-1625(2023)10-3755-09Research Progress on g-C 3N 4/Ag-Based Binary Composite Photocatalysts for Degradation of Environmental PollutantsBAI Linyang 1,CAI Zhaosheng 2(1.Jiangsu Institute of Tourism,Yangzhou 225000,China;2.School of Chemistry and Chemical Engineering,Yancheng Institute of Technology,Yancheng 224051,China)Abstract :Photocatalysis technology shows a good application prospect in the utilization of solar energy resource and has attracted worldwide attention.g-C 3N 4is a two-dimensional polymeric metal-free semiconductor material with the characteristics of facile synthesis,low cost,high chemical stability and non-toxicity,which has great potential in environmental remediation and energy conversion.However,g-C 3N 4has the drawbacks of poor visible light absorption capacity,low specific surface area and high recombination rate of photogenerated charge carriers,which limits its practical application.Constructing heterojunction photocatalyst has become one of effective pathways for boosting photocatalytic efficiency.Based on the inherent merits of Ag-based materials,a lot of researches have been carried out on g-C 3N 4/Ag-based binary photocatalysts and prominent results have been achieved.Recent advances on AgX (X =Cl,Br,I)/g-C 3N 4,Ag 3PO 4/g-C 3N 4,Ag 2CO 3/g-C 3N 4,Ag 3VO 4/g-C 3N 4,Ag 2CrO 4/g-C 3N 4,Ag 2O /g-C 3N 4and Ag 2MoO 4/g-C 3N 4composite photocatalysts for the degradation of environmental pollutants were summarized.The major challenges of g-C 3N 4/Ag-based binary composite photocatalysts were reviewed and the future development trends were also forecast.Key words :g-C 3N 4;Ag-based material;binary composite photocatalyst;photocatalytic performance;environmental pollutant㊀收稿日期:2023-05-15;修订日期:2023-06-12基金项目:江苏省高等学校自然科学研究面上项目(19KJD530002)作者简介:柏林洋(1967 ),男,博士,副教授㊂主要从事光催化材料方面的研究㊂E-mail:linybai@通信作者:蔡照胜,博士,教授㊂E-mail:jsyc_czs@0㊀引㊀言随着全球经济的快速增长和工业化进程的加快,皮革㊁印染㊁制药和化工等行业排放的环境污染物总量3756㊀陶㊀瓷硅酸盐通报㊀㊀㊀㊀㊀㊀第42卷也不断增长㊂这些环境污染物存在成分复杂㊁毒性大㊁难以降解等特点,对人们的身体健康和生态环境产生严重威胁,已成为制约经济和社会发展的突出问题㊂如何实现环境污染物的高效降解是目前亟待解决的重要问题㊂效率低㊁能耗高及存在二次污染是利用传统处理方法处置环境污染物的主要缺陷[1]㊂光催化技术作为一种新型的绿色技术,具有环境友好㊁成本低㊁反应效率高和无二次污染等优点,在解决环境污染问题方面具有很大的发展潜力,深受人们的关注[2-4]㊂g-C3N4属于一种非金属聚合物型半导体材料,具有二维分子结构,即C原子和N原子通过sp2杂化形成的共轭石墨烯平面结构,具有适宜的禁带宽度(2.7eV)和对460nm以下可见光良好的响应能力㊂g-C3N4具有合成原料成本低㊁制备工艺简单㊁耐酸耐碱和稳定性好等特点,在催化[5]㊁生物[6]和材料[7]等领域应用广泛㊂然而,g-C3N4较小的比表面积㊁较弱的可见光吸收能力和较快的光生载流子复合率等不足导致其光量子利用率不高,给实际应用带来较大困难[8]㊂为了克服上述问题,前人提出了对g-C3N4进行形貌调控[9]㊁元素掺杂[10-11]和与其他半导体耦合[12-13]等方法㊂其中,将g-C3N4与其他半导体耦合形成异质结光催化剂最为常见㊂Ag基半导体材料因具有成本合理㊁光电性能好和光催化活性高等特点而深受青睐,但仍存在光生载流子快速复合和光腐蚀等缺陷㊂近年来,人们将Ag基材料与g-C3N4进行复合,整体提高了复合光催化剂的催化性能,并由此取得了大量极有价值的科研成果㊂本文综述了近年来g-C3N4/Ag银基二元复合光催化剂的制备方法㊁性能和应用等方面的研究现状,同时展望了未来的发展趋势,期望能为该领域的研究人员提供新的思路㊂1㊀g-C3N4/Ag基二元复合光催化剂近年来,基于Ag基半导体材料能与g-C3N4能带结构匹配的特点,构筑g-C3N4/Ag基异质结型复合光催化体系已成为国内外的研究热点㊂这类催化剂通常采用沉淀法在g-C3N4表面负载Ag基半导体材料㊂其中,Ag基体的成核和生长是关键问题㊂通过对Ag基材料成核和生长工艺的控制,实现了Ag基材料在g-C3N4上的均匀分布㊂此外,通过对g-C3N4微观结构进行调控,使其具有较大的比表面积和较高的结晶度,从而进一步提高复合光催化剂的催化性能㊂相对于纯g-C3N4和Ag基光催化剂,g-C3N4/Ag基二元复合光催化剂通过两组分的协同效应和界面作用,不仅能提高对可见光的吸收利用率,而且能有效抑制g-C3N4和Ag基材料中光生e-/h+对的重组,从而提高复合光催化剂的活性和稳定性㊂在g-C3N4/Ag基二元复合光催化材料中,以AgX(X=Cl,Br,I)/g-C3N4㊁Ag3PO4/g-C3N4㊁Ag2CO3/g-C3N4㊁Ag3VO4/g-C3N4㊁Ag2CrO4/g-C3N4㊁Ag2O/g-C3N4和Ag2MoO4/g-C3N4为典型代表㊂1.1㊀AgX(X=Cl,Br,I)/g-C3N4二元复合光催化剂AgX(X=Cl,Br,I)在杀菌㊁有机污染物降解和光催化水解产氢等方面展现出优异的性能㊂但AgX (X=Cl,Br,I)是一种光敏材料,在可见光下容易发生分解,形成Ag0,从而影响其催化活性及稳定性㊂将AgX(X=Cl,Br,I)与g-C3N4复合是提升AgX(X=Cl,Br,I)使用寿命㊁改善光催化性能最有效的方法之一㊂Li等[14]采用硬模板法制备出一种具有空心和多孔结构的高比表面积g-C3N4纳米球,并以其为载体,通过沉积-沉淀法得到AgBr/g-C3N4光催化材料㊂XRD分析显示AgBr的加入并没有改变g-C3N4的晶体结构,瞬态光电流试验表明AgBr/g-C3N4光电流密度高于g-C3N4,橙黄G(OG)染料经10min可见光照射后的降解率达到97%㊂Shi等[15]报道了利用沉淀回流法制备AgCl/g-C3N4光催化剂,研究了AgCl的量对催化剂结构及光催化降解草酸性能的影响,确定了最佳修饰量,分析了催化剂用量㊁草酸起始浓度㊁酸度和其他有机成分对光催化活性影响,通过自由基捕获试验揭示了光降解反应中起主要作用的活性物质为光生电子(e-)㊁羟基自由基(㊃OH)㊁超氧自由基(㊃O-2)和空穴(h+)㊂彭慧等[16]采用化学沉淀法制备具有不同含量AgI的AgI/g-C3N4光催化剂,SEM测试表明AgI纳米颗粒分布在层状结构g-C3N4薄片的表面,为催化反应提供了更多的活性位㊂该系列催化剂应用于光催化氧化降解孔雀石绿(melachite green,MG)的结果显示,AgI/g-C3N4(20%,质量分数,下同)的光催化性能最好,MG经2h可见光辐照后去除率达到99.8%㊂部分AgX(X=Cl,Br,I)/g-C3N4二元复合光催化剂的研究现状如表1所示㊂第10期柏林洋等:g-C 3N 4/Ag 基二元复合光催化剂降解环境污染物的研究进展3757㊀表1㊀AgX (X =Cl ,Br ,I )/g-C 3N 4二元复合光催化剂光降解环境污染物的研究现状Table 1㊀Research status of AgX (X =Cl ,Br ,I )/g-C 3N 4binary composite photocatalysts forphotodegradation of enviromental pollutantsPhotocatalytst Synthesis method TypePotential application Photocatalytic activity Reference AgBr /g-C 3N 4Sonication-assisted deposition-precipitation II-schemeDegradation of RhB,MB and MO 100%degradation for RhB,95%degradation for MB and 90%degradation for MO in 10min [17]AgCl /g-C 3N 4Precipitation Z-schemeDegradation of RhB and TC 96.1%degradation for RhB and 77.8%degradation for TC in 120min [18]AgCl /g-C 3N 4Solvothermal +in situ ultrasonic precipitation Z-scheme Degradation of RhB 92.2%degradation in 80min [19]AgBr /g-C 3N 4Deposition-precipitation II-schemeDegradation of MO 90%degradation in 30min [20]AgI /g-C 3N 4In-situ growth II-scheme Degradation of RhB 100%degradation in 60min [21]㊀㊀Note:MO-methyl orange,RhB-rhodamine B,TC-tetracycline hydrochloride,MB-methyl blue.1.2㊀Ag 3PO 4/g-C 3N 4二元复合光催化剂纳米Ag 3PO 4禁带宽度为2.5eV 左右,对可见光有很好的吸收作用,且光激发后具有很强的氧化性,在污染物降解和光解水制氢等领域有良好的应用前景[22]㊂但是,纳米Ag 3PO 4易团聚,光生载流子的快速重组使光催化活性大大降低,此外,Ag 3PO 4还易受光生e -的腐蚀,从而影响稳定性㊂Ag 3PO 4与g-C 3N 4复合可显著降低e -/h +对的重组,有效提高光催化性能㊂Wang 等[23]采用原位沉淀法获得Z-型异质结构g-C 3N 4/Ag 3PO 4复合光催化剂,并有效地提高了e -/h +对的分离效率㊂TEM 结果显示,Ag 3PO 4粒子被g-C 3N 4纳米片所覆盖,UV-DRS 结果表明,Ag 3PO 4的添加使g-C 3N 4吸收边发生红移,且吸收光强度显著增强,光降解实验结果显示,30%g-C 3N 4/Ag 3PO 4光催化剂在40min 内能去除约90%的RhB㊂胡俊俊等[24]利用了原位沉淀法合成了一系列Ag 3PO 4/g-C 3N 4复合光催化剂,研究了Ag 3PO 4和g-C 3N 4的物质的量比对催化剂在可见光下催化降解MB 性能的影响,发现在最优组分下,MB 经可见光辐照30min 后可以被完全降解㊂Mei 等[25]采用焙烧-沉淀法制备了一系列Ag 3PO 4/g-C 3N 4复合光催化剂,并用于可见光条件下降解双酚A(bisphenol A,BPA),发现Ag 3PO 4质量分数为25%时,光催化降解BPA 的性能最好,3h 能降解92.8%的BPA㊂潘良峰等[26]采用化学沉淀法制备出一种具有空心管状的Ag 3PO 4/g-C 3N 4光催化剂,SEM 结果表明,Ag 3PO 4颗粒均匀分布于空心管状结构g-C 3N 4的表面,两者形成一个较强异质结构,将其用于盐酸四环素(tetracycline hydrochloride,TC)光催化降解,80min 能降解98%的TC㊂Deonikar 等[27]研究了采用原位湿化学法合成催化剂过程中使用不同溶剂(去离子水㊁四氢呋喃和乙二醇)对Ag 3PO 4/g-C 3N 4的结构和光降解MB㊁RhB 及4-硝基苯酚性能的影响,发现不同溶剂对复合光催化剂的形貌有着重要影响,从而影响光催化性能,其中以四氢呋喃合成的复合光催化剂的催化降解性能最佳,这是由于g-C 3N 4纳米片均匀包裹在Ag 3PO 4的表面,从而促使两者界面形成较为密切的相互作用,有利于e -/h +对的分离㊂部分Ag 3PO 4/g-C 3N 4二元复合光催化剂的研究进展见表2㊂表2㊀Ag 3PO 4/g-C 3N 4二元复合光催化剂光降解环境污染物的研究现状Table 2㊀Research status of Ag 3PO 4/g-C 3N 4binary composite photocatalysts for photodegradation of environmental pollutantsPhotocatalyst Synthesis method Type Potential application Photocatalytic activity Reference g-C 3N 4/Ag 3PO 4In situ precipitation Z-scheme Degradation of BPA 100%degradation in 180min [28]g-C 3N 4/Ag 3PO 4Hydrothermal Z-schemeDecolorization of MB Almost 93.2%degradation in 25min [29]g-C 3N 4/Ag 3PO 4In situ prepcipitation II-scheme Reduction of Cr(VI)94.1%Cr(VI)removal efficiency in 120min [30]g-C 3N 4/Ag 3PO 4Chemical precipitation Z-scheme Degradation of RhB 90%degradation in 40min [31]g-C 3N 4/Ag 3PO 4In situ precipitation Z-scheme Degradation of levofloxacin 90.3%degradation in 30min [32]Ag 3PO 4/g-C 3N 4Chemical precipitation Z-schemeDegradation of gaseous toluene 87.52%removal in 100min [33]Ag 3PO 4/g-C 3N 4Calcination +precipitation Z-scheme Degradation of diclofenac (DCF)100%degradation in 12min [34]Ag 3PO 4/g-C 3N 4In situ deposition Z-scheme Degradation of RhB and phenol 99.4%degradation in 9min for RhB;97.3%degradation in 30min for phenol [35]3758㊀陶㊀瓷硅酸盐通报㊀㊀㊀㊀㊀㊀第42卷续表Photocatalyst Synthesis method Type Potential application Photocatalytic activity Reference Ag3PO4/g-C3N4In situ hydrothermal II-scheme Degradation of sulfapyridine(SP)94.1%degradation in120min[36] Ag3PO4/g-C3N4In situ growth Z-scheme Degradation of berberine100%degradation in15min[37] g-C3N4/Ag3PO4In situ deposition Z-scheme Degradation of ofloxacin71.9%degradation in10min[38] Ag3PO4/g-C3N4Co-precipitation Z-scheme Degradation of MO98%degradation in10min[39]g-C3N4/Ag3PO4Calcination+precipitation Z-scheme Degradation of MO,RhB and TC95%degradation for MO in30min;[40]96%degradation for RhB in15min;80%degradation for TC in30min1.3㊀Ag2CO3/g-C3N4二元复合光催化剂Ag4d轨道和O2p轨道杂化,形成Ag2CO3的价带(valence band,VB);Ag5s轨道和Ag4d轨道进行杂化,形成Ag2CO3导带(conduction band,CB),而CB中原子轨道杂化会降低Ag2CO3带隙能,从而提高光催化活性[41]㊂纳米Ag2CO3带隙能约为2.5eV,可见光响应性好,在可见光作用下表现出良好的光催化降解有机污染物特性[42-43]㊂然而,经长时间光照后,Ag2CO3晶粒中Ag+会被光生e-还原成Ag0,导致其光腐蚀,引起光催化性能下降[44]㊂Ag2CO3与g-C3N4耦合,能够有效地抑制光腐蚀,促进e-/h+对的分离,进而改善光催化性能㊂An等[45]通过构筑Z型核壳结构的Ag2CO3@g-C3N4材料来增强Ag2CO3和g-C3N4界面间的相互作用,从而有效防止光腐蚀发生,加速光生e-/h+对的分离,实现了催化剂在可见光辐照下高效降解MO㊂Yin等[46]通过水热法制备Ag2CO3/g-C3N4光催化剂,探讨了g-C3N4的含量㊁合成温度对催化剂结构和光降解草酸(oxalic acid,OA)性能的影响,获得最优条件下合成的催化剂能在45min光照时间内使OA去除率达到99.99%㊂Pan等[41]采用煅烧和化学沉淀两步法,制备了一系列Ag2CO3/g-C3N4光催化剂,TEM结果显示,Ag2CO3纳米粒子均匀分布在g-C3N4纳米片表面,且形貌规整㊁粒径均一,光催化性能测试结果表明,60% Ag2CO3/g-C3N4光催化活性最高,MO和MB分别经120和240min可见光光照后,其降解率分别为93.5%和62.8%㊂Xiu等[47]使用原位水热法构筑了Ag2CO3/g-C3N4光催化剂,光降解试验结果表明,MO经可见光辐照1h的去除率为87%㊂1.4㊀Ag3VO4/g-C3N4二元复合光催化剂纳米Ag3VO4带隙能约为2.2eV,可用于催化可见光降解环境污染物,是一种具有应用前景的新型半导体材料㊂然而,如何提高Ag3VO4光催化性能,仍然是学者研究的重点㊂构建Ag3VO4/g-C3N4异质结催化剂是提高Ag3VO4的催化性能的一种有效方法㊂该方法能够降低Ag3VO4光生载流子的复合率,拓宽可见光的吸收范围㊂Hind等[48]通过溶胶凝胶法制备出一种具有介孔结构的Ag3VO4/g-C3N4复合光催化剂,该复合催化剂经60min可见光照射能将Hg(II)全部还原,其光催化活性分别是Ag3VO4和g-C3N4的4.3倍和5.4倍,主要是由于异质结界面处各组分间紧密结合以及催化剂具有较高的比表面积和体积比,从而促进光生载流子的分离㊂蒋善庆等[49]利用化学沉淀法制备了系列Ag3VO4/g-C3N4催化剂,催化性能研究结果表明,Ag3VO4负载量为20%(质量分数)时,其光催化降解微囊藻毒素的效果最好,可见光辐照100min后降解率为85.43%,而g-C3N4在相同条件下的降解率仅为18.76%㊂1.5㊀Ag2CrO4/g-C3N4二元复合光催化剂纳米Ag2CrO4具有特殊的晶格和能带结构,其带隙能为1.8eV,可见光响应良好,是一种非常理想的可见光区半导体材料㊂然而,Ag2CrO4存在自身的电子结构和晶体的缺陷,导致其光催化效率性能较差,严重影响了实际应用[50-52]㊂将Ag2CrO4与g-C3N4复合形成异质结光催化剂是提高其光催化效率和稳定性的一种有效途径,因为Ag2CrO4在光照下产生的光生e-快速地迁移到g-C3N4表面,可避免光生e-在Ag2CrO4表面聚集而引起光腐蚀㊂Ren等[53]利用SiO2为硬模板,以氰胺为原料,合成出具有中空介孔结构的g-C3N4,再通过化学沉淀法制备了系列g-C3N4/Ag2CrO4光催化剂,并将其用于RhB和TC的可见光降解,研究发现g-C3N4/Ag2CrO4催化剂具有较高比表面积和丰富的孔道结构,在可见光辐射下表现出较高的光催化活性㊂Rajalakshmi等[54]利用水热方法合成了一系列Ag2CrO4/g-C3N4光催化剂,并将其用于对硝基苯酚的光催化降解,结果表明,Ag2CrO4质量分数为10%时,其降解率达到97%,高于单组分g-C3N4或Ag2CrO4,原因是与第10期柏林洋等:g-C 3N 4/Ag 基二元复合光催化剂降解环境污染物的研究进展3759㊀Ag 2CrO 4和g-C 3N 4界面间形成了S-型异质结,能提高e -/h +对的分离效率㊂1.6㊀Ag 2O /g-C 3N 4二元复合光催化剂纳米Ag 2O 是一种理想的可见光半导体材料,在受到光辐照后,其电子发生跃迁,CB 上光生e -能够将Ag 2O 晶粒中Ag +还原成Ag 0,而VB 上h +能够使Ag 2O 的晶格氧氧化为O 2,导致其结构不稳定㊂然而,纳米Ag 2O 在有机物污染物降解方面表现出良好的稳定性[55],这是因为Ag 2O 的表面会随着光化学反应的进行被一定数量的Ag 0纳米粒子所覆盖,而Ag 0纳米粒子作为光生e -陷阱,能够降低e -在Ag 2O 表面的富集,同时,由于光生h +具有较强的氧化性能力,既能实现对有机污染物的直接氧化,又能避免其对晶格氧的氧化,从而提高了纳米Ag 2O 光催化活性和稳定性㊂Liang 等[56]在常温下采用简易化学沉淀法制备了p-n 结Ag 2O /g-C 3N 4复合光催化剂,研究发现,起分散作用的g-C 3N 4为Ag 2O 纳米颗粒的生长提供了大量成核位点并限制了Ag 2O 纳米颗粒聚集,p-n 结的形成以及在光化学反应过程中生成的Ag 纳米粒子,加速了光生载流子的分离和迁移,拓宽了光的吸收范围,在可见光和红外光照下降解RhB 溶液过程中表现出良好的催化活性,其在可见光和红外光照下反应速率分别是g-C 3N 4的26倍和343倍㊂Jiang 等[57]通过液相法制备了一系列介孔结构的g-C 3N 4/Ag 2O 光催化剂,试验结果表明,Ag 2O 的添加显著提高了g-C 3N 4/Ag 2O 光催化剂的吸光性能和比表面积,因此对光催化性能的提升有促进作用,当Ag 2O 含量为50%时,光催化分解MB 的效果最好,经120min 可见光光照后,MB 的脱除率达到90.8%,高于g-C 3N 4和Ag 2O㊂Kadi 等[58]以Pluronic 31R 1表面活性剂为软模板,以MCM-41为硬模板,合成出具有多孔结构的Ag 2O /g-C 3N 4光催化剂,TEM 结果显示,球形Ag 2O 的纳米颗粒均匀地分布于g-C 3N 4的表面,催化性能评价表明0.9%Ag 2O /g-C 3N 4复合光催化剂光催化效果最佳,60min 能完全氧化降解环丙沙星,其降解效率分别是Ag 2O 和g-C 3N 4的4倍和10倍㊂1.7㊀Ag 2MoO 4/g-C 3N 4二元复合光催化剂Ag 2MoO 4具有良好的导电性㊁抗菌性㊁环保性,以及优良的光催化活性,在荧光材料㊁导电玻璃㊁杀菌剂和催化剂等方面有着广阔的应用前景[59]㊂但Ag 2MoO 4带隙大(3.1eV),仅能对紫外波段光进行响应,限制了其对太阳光的利用㊂当Ag 2MoO 4与g-C 3N 4进行耦合时,可以将其对太阳光的吸收范围由紫外拓展到可见光区,从而提高太阳光的利用率㊂Pandiri 等[60]通过水热合成的方法,制备出β-Ag 2MoO 4/g-C 3N 4异质结光催化剂,SEM 结果显示该催化剂中β-Ag 2MoO 4纳米颗粒均匀地分布在g-C 3N 4纳米片的表面,光催化性能测试结果表明在3h 的可见光照射下,其降解能力是β-Ag 2MoO 4和g-C 3N 4机械混合物的2.6倍,主要原因在于β-Ag 2MoO 4和g-C 3N 4两者界面间形成更为紧密的异质结,使得e -/h +对被快速分离㊂Wu 等[61]采用简单的原位沉淀方法成功构建了Ag 2MoO 4/g-C 3N 4光催化剂,并将其应用于MO㊁BPA 和阿昔洛韦的降解,结果表明该催化剂显示出良好的太阳光催化活性,这主要是因为Ag 2MoO 4和g-C 3N 4界面间存在着一定的协同效应,可有效地提高对太阳光的利用率,降低载流子的复合概率㊂2㊀g-C 3N 4/Ag 基二元复合光催化剂电荷转移机理模型研究g-C 3N 4/Ag 基二元复合光催化剂在可见光的辐照下,价带电子发生跃迁,产生e -/h +对㊂e -被催化剂表面吸附的O 2捕获产生㊃O -2,并进一步与水反应生成㊃OH,形成的三种活性自由基(h +㊁㊃O -2和㊃OH),实现水中有机污染物的高效降解(见图1)㊂而光催化反应机理与载流子的迁移机制密切相关㊂目前,g-C 3N 4/Ag 基二元复合光催化剂体系中主要存在三种不同的光生载流子的转移机制,分别为I 型㊁II 型和Z 型㊂图1㊀g-C 3N 4/Ag 基二元复合光催化剂降解有机污染物的光催化反应机理Fig.1㊀Photocatalytic reaction mechanism of g-C 3N 4/Ag-based binary composite photocatalyst for degradation of organic pollutants3760㊀陶㊀瓷硅酸盐通报㊀㊀㊀㊀㊀㊀第42卷2.1㊀I 型异质结载流子转移机理模型图2(a)为I 型异质结构中的光生e -/h +对转移示意图㊂半导体A 和半导体B 均对可见光有响应,其中,半导体A 的带隙较宽,半导体B 的带隙较窄,并且半导体B 的VB 和CB 均位于半导体A 之间,在可见光的照射下,e -发生跃迁,从CB 到VB,半导体A 的CB 上的e -和VB 上的h +分别向半导体B 的CB 和VB 转移,从而实现了e -/h +对的分离㊂以Ag 2O /g-C 3N 4复合催化剂为例[58],当Ag 2O 和g-C 3N 4相耦合时,因为g-C 3N 4的VB 具有更正的电势,h +被转移到Ag 2O 的VB 上,同时,光激发e -在g-C 3N 4的CB 上,其电势较负,e -便传输到Ag 2O 的CB 上,CB 上e -与O 2结合形成㊃O -2,并进一步与H +结合生成了㊃OH,而有机物污染物被Ag 2O 的价带上h +氧化分解生成CO 2和H 2O㊂2.2㊀II 型异质结载流子转移机理模型II 型异质结是一种能级交错带隙型结构,如图2(b)所示,其中半导体A 的CB 电位较负,在可见光照射下,e -从CB 上转移到半导体B 的CB 上,h +从半导体B 的VB 转移到半导体A 的VB 上,从而使e -/h +对得以分离㊂以Ag 3PO 4@g-C 3N 4为例[62],由于g-C 3N 4的CB 的电势较Ag 3PO 4低,光生e -从g-C 3N 4迁移到Ag 3PO 4的CB 上,而Ag 3PO 4的CB 电势较g-C 3N 4高,h +从Ag 3PO 4的VB 迁移到g-C 3N 4的VB 上,从而实现e -/h +对的分离,g-C 3N 4表面的h +可直接氧化降解MB,而Ag 3PO 4表面积聚的电子又会被氧捕获,产生H 2O 2,并进一步分解成㊃OH,从而加快MB 的降解㊂上述I 型和II 型结构CB 的氧化能力和VB 还原能力低于单一组分,造成复合半导体的氧化还原能力降低[63]㊂2.3㊀Z 型异质结载流子转移机理模型构建Z 型异质结光光催化剂使得e -和h +沿着特有的方向迁移,有效解决复合催化剂氧化还原能力降低问题[64]㊂Z 型异质结催化剂e -/h +对的迁移方向如图2(c)所示,e -从半导体B 的电势较高的CB 转移到半导体A 的电势较低的VB 进行复合,从而实现半导体A 的e -和半导体B 的h +发生分离㊂h +在半导体B 表面氧化性能更强,在半导体A 上e -具有较高还原特性,两者共同作用使环境污染物得以顺利降解㊂为了更好地解释Z 型异质结h +和e -迁移机理,以Ag 3VO 4/g-C 3N 4复合光催化剂为例[48],复合光催化剂经可见光激发后,Ag 3VO 4和g-C 3N 4都发生了e -跃迁,在Ag 3VO 4的CB 上e -与g-C 3N 4的VB 上h +进行复合时,e -对Ag 3VO 4的腐蚀作用被削弱,同时,也实现了g-C 3N 4的CB 上e -和Ag 3PO 4的价带上h +发生分离,g-C 3N 4的CB 上e -具有较强的还原性,将Hg 2+还原成Hg 0,而Ag 3PO 4的VB 上h +具有较强的氧化性,可将HOOH氧化生成CO 2和H 2O㊂图2㊀电子-空穴对转移机理示意图Fig.2㊀Schematic diagrams of electron-hole pairs transfer mechanism 3㊀结语和展望g-C 3N 4/Ag 基二元复合光催化剂因其较强的可见光响应和优异的光催化性能,在环境污染物的降解方面具有广阔的发展空间㊂近年来,国内外研究人员在理论研究㊁制备方法和光催化性能等多个领域取得了重要进展,为光催化理论的发展奠定了坚实的基础㊂然而,g-C 3N 4/Ag 基二元复合光催化剂在实际应用中还面临诸多问题,如制备工艺复杂㊁光腐蚀㊁光催化剂回收利用困难㊁光催化降解污染物的反应机理尚不明确等,第10期柏林洋等:g-C3N4/Ag基二元复合光催化剂降解环境污染物的研究进展3761㊀现有的光催化降解模型仍有较大的分歧,亟待深入研究㊂为了获得性能优良的g-C3N4/Ag基复合光催化剂,实现产业化应用,应进行以下几方面的研究:1)在g-C3N4/Ag基二元光催化剂的基础上,构建多元复合光催化剂,是进一步提升光生载流子分离效率的有效㊁可靠手段,也是当今和今后光催化剂的研究重点㊂2)对g-C3N4/Ag基二元光催化剂体系中e-/h+对的转移㊁分离和复合等过程进行系统研究,并阐明其光催化反应机制㊂3)针对当前合成的g-C3N4材料多为体相,存在着颗粒大㊁比表面积小㊁活性位少等缺陷,应通过对g-C3N4材料的形状㊁形貌及尺寸的调控,来实现Ag 基材料在g-C3N4材料表面的均匀分布,降低e-/h+对的重组概率,从而大幅度提高复合光催化剂的性能㊂4)Ag基材料的光腐蚀是导致光催化活性和稳定性下降的重要因素,探索一种更为有效的光腐蚀抑制机制,是将其推广应用的关键㊂5)当前合成的g-C3N4/Ag基二元复合光催化剂多为粉末状,存在着易团聚㊁难回收等问题,从而限制了其循环利用㊂因此,需要开展g-C3N4/Ag基二元复合光催化剂回收和再利用的研究,这将有利于社会效益和经济效益的提高㊂参考文献[1]㊀LIN Z S,DONG C C,MU W,et al.Degradation of Rhodamine B in the photocatalytic reactor containing TiO2nanotube arrays coupled withnanobubbles[J].Advanced Sensor and Energy Materials,2023,2(2):100054.[2]㊀DIAO Z H,JIN J C,ZOU M Y,et al.Simultaneous degradation of amoxicillin and norfloxacin by TiO2@nZVI composites coupling withpersulfate:synergistic effect,products and mechanism[J].Separation and Purification Technology,2021,278:119620.[3]㊀ZHAO S Y,CHEN C X,DING J,et al.One-pot hydrothermal fabrication of BiVO4/Fe3O4/rGO composite photocatalyst for the simulated solarlight-driven degradation of Rhodamine B[J].Frontiers of Environmental Science&Engineering,2021,16(3):1-16.[4]㊀JUABRUM S,CHANKHANITTHA T,NANAN S.Hydrothermally grown SDS-capped ZnO photocatalyst for degradation of RR141azo dye[J].Materials Letters,2019,245:1-5.[5]㊀SUN Z X,WANG H Q,WU Z B,et al.g-C3N4based composite photocatalysts for photocatalytic CO2reduction[J].Catalysis Today,2018,300:160-172.[6]㊀LIN L,SU Z Y,LI Y,et parative performance and mechanism of bacterial inactivation induced by metal-free modified g-C3N4undervisible light:Escherichia coli versus Staphylococcus aureus[J].Chemosphere,2021,265:129060.[7]㊀DANG X M,WU S,ZHANG H G,et al.Simultaneous heteroatom doping and microstructure construction by solid thermal melting method forenhancing photoelectrochemical property of g-C3N4electrodes[J].Separation and Purification Technology,2022,282:120005. [8]㊀VAN KHIEN N,HUU H T,THI V N N,et al.Facile construction of S-scheme SnO2/g-C3N4photocatalyst for improved photoactivity[J].Chemosphere,2022,289:133120.[9]㊀LINH P H,DO CHUNG P,VAN KHIEN N,et al.A simple approach for controlling the morphology of g-C3N4nanosheets with enhancedphotocatalytic properties[J].Diamond and Related Materials,2021,111:108214.[10]㊀XIE M,TANG J C,KONG L S,et al.Cobalt doped g-C3N4activation of peroxymonosulfate for monochlorophenols degradation[J].ChemicalEngineering Journal,2019,360:1213-1222.[11]㊀ZHEN X L,FAN C Z,TANG L,et al.Advancing charge carriers separation and transformation by nitrogen self-doped hollow nanotubes g-C3N4for enhancing photocatalytic degradation of organic pollutants[J].Chemosphere,2023,312:137145.[12]㊀AL-HAJJI L A,ISMAIL A A,FAYCAL A M,et al.Construction of mesoporous g-C3N4/TiO2nanocrystals with enhanced photonic efficiency[J].Ceramics International,2019,45(1):1265-1272.[13]㊀CUI P P,HU Y,ZHENG M M,et al.Enhancement of visible-light photocatalytic activities of BiVO4coupled with g-C3N4prepared usingdifferent precursors[J].Environmental Science and Pollution Research,2018,25(32):32466-32477.[14]㊀LI X W,CHEN D Y,LI N J,et al.AgBr-loaded hollow porous carbon nitride with ultrahigh activity as visible light photocatalysts for waterremediation[J].Applied Catalysis B:Environmental,2018,229:155-162.[15]㊀SHI H L,HE R,SUN L,et al.Band gap tuning of g-C3N4via decoration with AgCl to expedite the photocatalytic degradation and mineralizationof oxalic acid[J].Journal of Environmental Sciences,2019,84:1-12.[16]㊀彭㊀慧,刘成琪,汪楚乔,等.AgI/g-C3N4复合材料制备及其降解孔雀石绿染料性能[J].环境工程,2019,37(4):93-97.PENG H,LIU C Q,WANG C Q,et al.Preparation of AgI/g-C3N4composites and their degradation performance of malachite green dyes[J].Environmental Engineering,2019,37(4):93-97(in Chinese).[17]㊀LIANG W,TANG G,ZHANG H,et al.Core-shell structured AgBr incorporated g-C3N4nanocomposites with enhanced photocatalytic activityand stability[J].Materials Technology,2017,32(11):675-685.[18]㊀LI Y B,HU Y R,LIU Z,et al.Construction of self-activating Z-scheme g-C3N4/AgCl heterojunctions for enhanced photocatalytic property[J].Journal of Physics and Chemistry of Solids,2023,172:111055.3762㊀陶㊀瓷硅酸盐通报㊀㊀㊀㊀㊀㊀第42卷[19]㊀XIE J S,WU C Y,XU Z Z,et al.Novel AgCl/g-C3N4heterostructure nanotube:ultrasonic synthesis,characterization,and photocatalyticactivity[J].Materials Letters,2019,234:179-182.[20]㊀YANG J,ZHANG X,LONG J,et al.Synthesis and photocatalytic mechanism of visible-light-driven AgBr/g-C3N4composite[J].Journal ofMaterials Science:Materials in Electronics,2021,32:6158-6167.[21]㊀HUANG H,LI Y X,WANG H L,et al.In situ fabrication of ultrathin-g-C3N4/AgI heterojunctions with improved catalytic performance forphotodegrading rhodamine B solution[J].Applied Surface Science,2021,538:148132.[22]㊀GUO C S,CHEN M,WU L L,et al.Nanocomposites of Ag3PO4and phosphorus-doped graphitic carbon nitride for ketamine removal[J].ACSApplied Nano Materials,2019,2(5):2817-2829.[23]㊀WANG H R,LEI Z,LI L,et al.Holey g-C3N4nanosheet wrapped Ag3PO4photocatalyst and its visible-light photocatalytic performance[J].Solar Energy,2019,191:70-77.[24]㊀胡俊俊,丁同悦,陈奕桦,等.Ag3PO4/g-C3N4复合材料的制备及其光催化性能[J].精细化工,2021,38(3):483-488.HU J J,DING T Y,CHEN Y H,et al.Preparation and photocatalytic application of Ag3PO4/g-C3N4composites[J].Fine Chemicals,2021,38(3):483-488(in Chinese).[25]㊀MEI J,ZHANG D P,LI N,et al.The synthesis of Ag3PO4/g-C3N4nanocomposites and the application in the photocatalytic degradation ofbisphenol A under visible light irradiation[J].Journal of Alloys and Compounds,2018,749:715-723.[26]㊀潘良峰,阎㊀鑫,王超莉,等.中空管状g-C3N4/Ag3PO4复合催化剂的制备及其可见光催化性能[J].无机化学学报,2022,38(4):695-704.PAN L F,YAN X,WANG C L,et al.Preparation and visible light photocatalytic activity of hollow tubular g-C3N4/Ag3PO4composite catalyst[J].Chinese Journal of Inorganic Chemistry,2022,38(4):695-704(in Chinese).[27]㊀DEONIKAR V G,KOTESHWARA R K,CHUNG W J,et al.Facile synthesis of Ag3PO4/g-C3N4composites in various solvent systems withtuned morphologies and their efficient photocatalytic activity for multi-dye degradation[J].Journal of Photochemistry and Photobiology A: Chemistry,2019,368:168-181.[28]㊀DU J G,XU Z,LI H,et al.Ag3PO4/g-C3N4Z-scheme composites with enhanced visible-light-driven disinfection and organic pollutantsdegradation:uncovering the mechanism[J].Applied Surface Science,2021,541:148487.[29]㊀NAGAJYOTHI P C,SREEKANTH T V M,RAMARAGHAVULU R,et al.Photocatalytic dye degradation and hydrogen production activity ofAg3PO4/g-C3N4nanocatalyst[J].Journal of Materials Science:Materials in Electronics,2019,30(16):14890-14901.[30]㊀AN D S,ZENG H Y,XIAO G F,et al.Cr(VI)reduction over Ag3PO4/g-C3N4composite with p-n heterostructure under visible-light irradiation[J].Journal of the Taiwan Institute of Chemical Engineers,2020,117:133-143.[31]㊀YAN X,WANG Y Y,KANG B B,et al.Preparation and characterization of tubelike g-C3N4/Ag3PO4heterojunction with enhanced visible-lightphotocatalytic activity[J].Crystals,2021,11(11):1373.[32]㊀高闯闯,刘海成,孟无霜,等.Ag3PO4/g-C3N4复合光催化剂的制备及其可见光催化性能[J].环境科学,2021,42(5):2343-2352.GAO C C,LIU H C,MENG W S,et al.Preparation of Ag3PO4/g-C3N4composite photocatalysts and their visible light photocatalytic performance[J].Environmental Science,2021,42(5):2343-2352(in Chinese).[33]㊀CHENG R,WEN J Y,XIA J C,et al.Photo-catalytic oxidation of gaseous toluene by Z-scheme Ag3PO4-g-C3N4composites under visible light:removal performance and mechanisms[J].Catalysis Today,2022,388/389:26-35.[34]㊀ZHANG W,ZHOU L,SHI J,et al.Synthesis of Ag3PO4/g-C3N4composite with enhanced photocatalytic performance for the photodegradation ofdiclofenac under visible light irradiation[J].Catalysts,2018,8(2):45.[35]㊀ZHANG M X,DU H X,JI J,et al.Highly efficient Ag3PO4/g-C3N4Z-scheme photocatalyst for its enhanced photocatalytic performance indegradation of rhodamine B and phenol[J].Molecules,2021,26(7):2062.[36]㊀LI K,CHEN M M,CHEN L,et al.In-situ hydrothermal synthesis of Ag3PO4/g-C3N4nanocomposites and their photocatalytic decomposition ofsulfapyridine under visible light[J].Processes,2023,11(2):375.[37]㊀汲㊀畅,王国胜.Ag3PO4/g-C3N4异质结催化剂可见光降解黄连素[J].无机盐工业,2022,54(4):175-180.JI C,WANG G S.Degradation of berberine by visible light over Ag3PO4/g-C3N4heterojunction catalyst[J].Inorganic Chemicals Industry, 2022,54(4):175-180(in Chinese).[38]㊀CHEN R H,DING S Y,FU N,et al.Preparation of a g-C3N4/Ag3PO4composite Z-type photocatalyst and photocatalytic degradation ofOfloxacin:degradation performance,reaction mechanism,degradation pathway and toxicity evaluation[J].Journal of Environmental Chemical Engineering,2023,11(2):109440.[39]㊀HAYATI M,ABDUL H A,ZUL A M H,et al.In-depth investigation on the photostability and charge separation mechanism of Ag3PO4/g-C3N4photocatalyst towards very low visible light intensity[J].Journal of Molecular Liquids,2023,376:121494.[40]㊀DING M,ZHOU J J,YANG H C,et al.Synthesis of Z-scheme g-C3N4nanosheets/Ag3PO4photocatalysts with enhanced visible-lightphotocatalytic performance for the degradation of tetracycline and dye[J].Chinese Chemical Letters,2020,31(1):71-76.[41]㊀PAN S G,JIA B Q,FU Y S.Ag2CO3nanoparticles decorated g-C3N4as a high-efficiency catalyst for photocatalytic degradation of organiccontaminants[J].Journal of Materials Science:Materials in Electronics,2021,32(11):14464-14476.。

宜兴抽水蓄能电站专业英语词汇

第一部分英译汉Aascend 升（降）abbreviation 缩写ability of withstand seism 耐受地震能力abrasion-resistant 耐磨absorber 吸附装置absorptance 吸收比abut(ting) 毗邻AC (Assembling Check) 安装检查AC input reactor 交流输入电抗器AC sampling module 交流采样模件acceleration 加速度accessible 可进入accommodate 容纳；使适应accounts for 含量为acetylene 乙炔acoustic 声波acquisition 征地activate 激活active power 有功功率adapt to 适应adaptability to 适应能力adhesiveness 附着性adjustable current limiting resistor 可调式限流电阻admission 允许进入adverse influence to 对……不利于adverse 不利的AECR (Automatic Excitation Current Regulator)自动励磁电流调节aeration 通风通气affiliate 隶属affix 粘贴afforest 绿化AGC (automatic generating control) 自动发电控制aggregate 骨料aggregating 密集aging 老化AGM (air gap measurement) 气隙测量AI (analog input) 模拟量输入Air compressor 空压机air condition 空调air cooler 空气冷却器air gap 气隙air gap monitoring system 气隙监测系统air housing 风洞air purification device 空气净化装备Air reservoir 储气罐alarm cycles 报警呼叫周期algorithms 算法alias 别名化名aligne 对齐成一线altitude 海拔alignment 校正alkali 碱alleviate 缓和allot 分派alloy steel 合金钢along with 随着Alternate 替补侯选alternating current 交流altitude 海拔altitude difference 交差aluminum alloy 铝合金aluminum spacer 铝制撑条ambient temperature 环境温度ambiguity 含糊、不明确amendment 修改件amicably 友善ammeter 电流表amortisseur bar 阻尼条amortisseur ring 阻尼环amortisseur ring connector 阻尼环接头amortisseur ring pulling rod 阻尼环拉杠amortisseur winding 阻尼绕组amortisseur 阻尼器amortization 分期偿还ample 足够amplitude 振幅amplitude coefficient 振幅系数analog input ( AI) signals 模拟量输入信号analog output ( AO) signals 模拟量输出信号analogue signal 模拟信号analysis 分析anchor bar 锚杆anchorage 锚固ancillary 辅助的、副的ancillary to 附属Anionic(Cationic) 阴 /阳Anneal 退火annealed copper 退火软铜annual forced outage ratio 年强迫停运率annual leakage rate 年泄漏率annuity 年本息anti wear plate 抗磨板anticipate 预期anti-corona layer 防晕层anti-corrosion copper earthing terminals 防锈铜接地端子anti-interference capacity 抗干扰能力anti-pumping 防跳跃anti-water hammer 防水锤AO (analog output) 模拟量输出Apparent 明显Appearance 外观application software 应用软件application tools 应用工具approved products 定型arbitrary 仲裁；公断arc contact 电弧触头arc extinguishing chamber 灭弧室architecture 体系；结构archived as-built drawings 档案竣工图argil 陶土argon arc electrical welding method 氩弧焊方式argon arc electrical 氩弧arm 支臂arm fabricated type 支臂组合式armature 电枢armored ayer 铠装层array of 一批arrestor 避雷器art design 工艺设计artesian 干线artesian 自流井自喷井artificial 人工as pertains to 部分asbestos 石棉asbestos product 石棉制品as-built 竣工ascertain 查明aspire 追求assembling stress 装配应力assembly 装配assignment 转让assume 承担assumption 假定asymmetrical fault 不对称故障asymmetrical short circuit 不对称短路asymmetry 不对称asynchronously 不同步atmospheric over voltage 大气过电压attenuation 衰减attenuator 衰减器attest 证明attorney 委托audible alarming system 音响报警系统AFC(automatic frequency control unit) 自动频率控制ALR(automatic load regulator) 自动负载调节器auspices（under the ～ of ）赞助领导automatic alarm device 自动告警系统automatic bi-directional self-balancing follower自动双相自平衡跟踪装置automatic blow-off valve 自动排气阀automatic elements 自动化元件automatic excitation current regulator 自动励磁电流调节器automatic excitation regulating system 自动励磁调节系统automatic phonetic alarming system 语音电话自动告警系统automatic signal identification 自动识别automatic synchronizing device 自动准同步装置（AVR）automatic thermostatic heater 自动恒温控制加热器automatic voltage regulator 自动电压调节器automatic water spray system 自动喷水系统automatically 自动地autonomous 自发auxiliaries 附属设备AVC (automatic voltage control) 自动电压控制AVR (automatic voltage regulator) 自动电压调节axes 轴axially 轴向axonometric 轴侧法azimuth 方位角B（BDS） Bid Data Sheet 投标资料表（naval） brass 黄铜（oriented）（pre-split）blast (定向)(予警)爆炸（to be）Bound to 一定B/L bill of lading 提货单Babbit metal 巴氏合金back-to-back starting method 背靠背起动方式baffle 缓冲板balance weight 平衡重锤balancing weight 平衡重锤/配重balustrade 栏栅balustrade 护栏balustrade 拉杆banking fire 压火barracks 营房barrier 隔板屏障base plate 基础板base settlement 基础沉降BCDI/BCDO (BCD code input/output) 码输入/输出be galvanized 镀锌be polished 抛光be updated 升级bearing 轴承bearing capacity 承载能力bearing lubricating system 轴承润滑系统bearing pad 轴瓦bearing support 轴承支架bellow 波纹管bellow 伸缩bench 形成台阶beneficiary 受益方BER (Bit Error Rate) 误码率berm 马道between opened gap 断口间Bevel 斜角Bifurcation 分枝岔管BIL (lightning impulse withstand voltage)雷电冲击耐受电压blank endorse 空白背书blister 泡block cylinder 封堵缸体block diagram 框图block stone 块石block 封堵blockage 阻塞blow-off valve 排气阀bolt 螺栓bolts 螺栓book-type 笔记本boom 吊臂booster pump 增压泵borrowing 取土动土bottom plate 底板bottom ring 底环bound separately 独立成册brace 支撑拉条bracket 盖板机架braid 辫子brake piston 制动活塞brake ring 制动环braking friction 制动摩擦braking shoe 制动瓦braking system 制动(停机)系统branch circuit 分支回路brazed joint failure 机械损伤brazing machine 焊机breach 不履行breaking capacity 开断容量breaking load current 开断负荷电流breaking ring 制动环breast walls 防浪墙breather 吸潮器bridge crane 桥式起重机brightness 亮度broach 拉刀brochure 小册子bronze 青铜bruise 擦伤brush holder 刷握buchholtz 瓦斯buckle (由于压力热力)变形buffer layer 缓冲层buffer 缓冲器Bulkhead for water pressure test 涡壳试压封堵盖bulkhead gate 检修闸门bulkhead 堵头burden 负载bus coupler 母联busbar circuit breaker 母联断路器busbar tunnel 母线洞bushing 套管bushing axis 套管轴bushing conductor 套管导体bus-tie 母联butterfly spring 蝶形弹簧buzz 蜂鸣by-pass disconnector 旁路隔离开关C(to be)conversant with 熟练cable 电缆cable clamps 电缆卡具cable conduits 电缆管cable connector 电缆接线器cable general layout 缆总布置图cable joint 电缆接头cable metal protection sheathes 电缆金属护层cable monitoring device 电缆监测装置cable rack and fittings 电缆架及紧固件cable seal-ends 电缆终端cable trays 电缆桥架calcification 钙质calculation capability 运算能力calibration 标准校正caliper 卡钳call 调用calorimetric 卡cantilever 悬臂capacitance cone 电容锥capacitive current 电容电流capacity tariff 容量价capacity 容量capillary 毛细管capital investment 固定资产投资carbon brush 碳刷carbon steel 碳素钢cards frame 插件框架cards 插接板carrying capacity 载流能力cash trees land 经济林cashier’s or certified check本票或保付汇票casing 外壳cast epoxy bushing 环氧模压绝缘套管cast steel 铸钢catalogue cuts 样本摘要categorization 范畴化caterpillar crane 履带起重机cavern 洞室cavitation 空蚀cavity 洞CBFP(circuit-breaker failure protection)断路器故障保护CD-Recorder device 可刻写光盘设备center column 中心柱center frame for measuring 转子测圆架the circularity of rotorcenter frame for measuring 定子测圆架the circularity of statorcenter hub upper and lower disc 中心体上、下园盘center hub vertical rib & supporting plat中心体立筋、撑板central control building 中控楼central control room 中控室central controller of protective relaying information继电保护信息集中管理器centrifugal force 离心力centrifuge 离心certify 证实change over 切换channel automatic changeover 通信自动切换char 炭黑characteristic 特性chassis 底盘check valve 逆止阀chipper 铲头工具chisel 凿chock 垫木chopped wave 截波chopped 载chord 衍铉chromaticity 色度CIECC (China international engineering 中国国际工程咨询公司consulting company)CIF (Cost, Insurance and Freight) 成本加保险费、运费CIP [Carriage and Insurance Paid to (place)]运费和保险费付至(地点) circuit breaker 断路器circuit transformer 电流互感器circular broach 圆拉刀circular hoisting track 环形吊轨circulation fund 流动资金circumferential speed 圆周速度civil works 土建clamping fixture 夹具clarification 澄清classification 分类clear width 净宽clearance 间隙clearance customs 清关clearance 间距clockwise 顺时针CMT(Commissioning and Maintenance Test) 调试及维护试验CNAO(China National Audit Office ) 中国国家审计署cockle 折皱codes 规程cofferdam 围堰cohesion 粘合力内聚力cold rolled silicon steel sheet 冷轧硅钢片cold-roll silicon steel sheet ofgrain orientation withhigh magnetic conductivity 导率高的晶粒取向冷轧硅钢片collar 滑转子打眼collate 比照collector assembly 集电装置collector ring 集电环collision 碰collocate 布置collusive 勾结color photo jet printer 彩色照相喷墨打印机combinational screen wall 组合屏幕墙combined axial load 组合轴向荷载combined tangential and radial key 径,切向复合键combined/intersection network 组合／交汇网combustion chamber 燃烧室commence 开始commissioning 试运行commitment fee 承诺费common mode noise attenuation 共模抑制communication interface 通信接口communication optic fiber cables 通信光缆communication processor and controller 通信处理器及控制器communication protocol 通信规约commutation diode 硅整流二级管commutation diode 整流comparison 比较compartment(alize) 分割小室compatibility 兼容性compatible to 匹配compensating the displacement 位移补偿competent 有能力的competitiveness 竞争性compile 汇编编写compliance with 依照comply （with）满足compo insurance 工伤保险component of negative sequence current 负序电流分量composite video port 复合视频接口composite 混合复合compound materials 复合材料comprise 组成compulsory 强制性的concavity 凹computer supervisory and control system 计算机监控系统conceived 设想concentricity 同心度concise 简明concrete floor 混凝土楼板concrete foundation 混凝土基础concrete pole 水泥杆concrete Pump Truck 砼泵concurrently 同时发生concurs with 同意condensation 收缩condenser mode 调相工况condenser mode 调相condenser operation 调相conducting ring 导电环conductivity 导电conductor 导体conductor screening 导体屏蔽conductor temperature 线芯温度conduit 管道confidential 秘密configuration 外形、轮廓、布置、配置configuration drawing 配置图configuration software 组态软件configuration 配置confiscate 被征用conflict 矛盾conflict 冲突conformity to 附合congregate 组装conical 锥connecting bolt between main shaft and runner主轴与转轮连接螺栓connecting bolt for shaft coupling flange 转轴连接法兰螺栓connecting cable 连接电缆connecting pipe 连接管路connecting studs 接线柱connecting terminals 接线端子connection wires 连接导线consecutive 联续consecutive 连续consent 同意、一致conservation of water and soil 水土保持conservative 保守consigne 委托consignee 收货人consistency 一致性consistent with 一致console 控制台console 台面conspicuous 连续constant frequency and constant voltage 恒频恒压constant 常数constitute 构成组成任命constrainedly 勉强constraint 强制construction substation 施工变电所construe 解释consumable 易耗件contaminate 污染contaminate 弄脏contamination 污染contingency 偶然意外continuous charging capacity 持续充电容量continuous reactive output 持续无功出力contracted 承包contradiction 矛盾contrary to 相反contrast 对照contrast 对比度control cable 控制电缆control cubicle 控制柜control mode selector switch 控制权选择开关control panel 控制盘control protection cable 控制保护电缆control switch for unit start/stop 机组启、停控制开关convene 召开convener 召集人convenient 便利的converge 汇聚conversion accuracy 转换精度convexity 凸conveyance 输送cool state 冷态cooler 冷却器cooling system 冷却系统cooling tube of cooler 冷却器冷却管cooper lugs 铜鼻子coordination 协调copper busbar 铜排copper earthing screw 铜质接地螺钉copper flexible braid 铜编织线copper lug 铜鼻子copper pigtails 铜辨子copper strand wires 铜绞线copper strip 铜片copper wire 铜线core end plate 齿压板core number 芯数corollary 辅助配套corona inception 起晕corrosion 腐蚀corrosion-resistance 抗腐蚀能力corruption 腐败counter clockwise 逆时针counter measures 对策countersign 会签counterweight 配重coupler 电容耦合器coupling flange 连接法兰coupling surface 法兰接合面coupon 附单CPM (Critical Path Method) 关键路径法CPU (Central Processing Unit) 中央处理器CPU redundant CPU冗余crack 裂缝cracking 龟裂crank 曲柄crank shaft box 曲轴箱crawler Hydraulic Pressure Forward Excavator履带式正铲挖掘车crawler-type Surface Hydraulic Drill Rig 履带式露天钻creepage 漏电crest 脊criteria 标准criterion 尺度标准依据critical speed 临界速度critical speed 临界转速cross section 截面cross-check 仔细检查cross-link polyethylene insulation (XLPE) 交联聚乙烯cross-section 截面CRT 屏幕显示器crushed stone 碎石CSCS (computer supervisory and control system)计算机监控系统CT’s (Current transformers) 电流互感器cubicle 柜cultural relics 文物culture 放养current balancing factor 均流系数current carrying area 过流面积current carrying capacity 载流量current density 电流密度current limiting reactor 限流电抗器current 气流current-carrying 载流量cursor 光标cushion layer 过渡层（垫层）cushioning 缓冲custody 监护保管D（as-built）drawing 竣工（partial）discharging 局部放电dacron 涤纶dam crest 坝脊面dam site 坝址damping winding 阻尼绕组damping 阻尼damp-proof 耐潮的damp-proof measures 防潮措施DAQ(Data Acquisition System) 数据采集系统data acquisition 数据采集data acquisition and processing 数据采集与处理data buffer 数据缓冲data light processing projector 数字光处理投影机data sampling 数据采样database management system 数据库管理系统database 数据库DC Dimensional Check 尺寸检查DC 220V distribution cable 直流220V配电电缆DC distribution panel 直流分配电屏DC field flashing circuit 直流起励回路DC flat-wave reactor 直流平波电抗器DC resistance 直流电阻De-aerate 除气debugging 调试debugging terminal 调试终端debugging 调试debur 去毛刺decompose 分解deduct 扣除de-excitation 灭磁deficiency 缺陷deficit 抵债definite time 定时deflection 挠度deflection / deformation 变型degrade 瓦解de-ionize 去离子delineate 描写deliver inductive reactive power 发送感性无功demagnetize 消磁demarcation 勘测demonstrate 论证denominate 给…命名denotation 表示dense 密集dependability 可靠性deposit 料场depreciation 折旧费贬值depression 凹地deprive 剥夺derivative 派生derivative 微分derive 获得deriving from 由…造成de-sicator 干燥器designation 标记destination port 目的港detecting leakage 检漏deterioration 变质detriment 损害deviation 偏差devoman 泥盆纪dewater 压水DI (digital input) 数字输入dial indicator 百分表dialect 方言diaphragm 横膈膜dielectric dissipation factor test 介质损失角测量试验dielectric loss angle 介电损失角dielectric loss 介质损耗dielectric resistance 绝缘电阻dielectric strength test 介电强度试验dielectric 介质diesel generator 柴油发电机differential initiation 微差起爆differential mode noise attenuation 常模抑制differential protection 差动保护differential settlement 变形digital input ( DI) signals 数字量输入信号digital multimeter 数字万用表digital output ( DO) signals 数字量输出信号dike 堤堰坝dilatancy 膨胀diluted 冲淡dip(ped) 倾向(浸)dipped 浸direct axis and quadrate axis 直轴与横轴disburse 支付disc type 圆盘式discharge arcing 晕带discharge counter/ recorder 放电记数器discharge ring 泄流环disconnector 隔离开关disconnector of starting circuit 起动回路隔离开关discrepancy 不符discrete 分立的discretion 处理权限dispute 争议discriminates 区别dismantle 拆装dismantling 拆卸dispatch 调度dispatching calibre 配电能力displacement 位移display picture generation 画面生成disposition 配置dissipation 驱散distinction 区别distinctive seasons 四季分明distinguishability/resolution 分辨率distortion 畸变distribution room 配电室distribution transformer 配电变压器disturbance 扰动diversion 引水divert 转移dividend 分红利divulge 泄漏DLP (Data Light Processing Projector) 数字光处理器DMD (digital micro mirror device) 数字微反射器DO (digital output) 数字量输出dominant 支配double coil, two positionelectromagnetic valve 双线圈两位电磁阀dovetail （key bar）燕型橛dovetail pin 燕尾销dowel pins 定位销down-land 丘陵draft tube lower liner 尾水管下部里衬draft tube 尾水管[(upper /lower) liner] 尾水管[(上/下部)里衬drain valve 排水阀drainage ditches 排水沟drainage 排水draw ring 牵引环, 拉延环drawing software 图形软件DRC 数字式保护校验仪(Digital protection relay checkout device)dredge 疏竣dressing stick 整形棒drift 漂移driving vibrator 单钢轮振动压实机droop characteristic 调差特性DSCR（debt service coverage rate）偿债保证比DSP(digital signal processor) 数字信号处理DTV (draft tube valve) 尾管阀门dump truck 自卸车dumping 缓冲duplicable 可复制的duplicate bus input circuit 双总线输入回路duplicate channel digital oscillograph 双通道数字型示波器duplicate trip coil 双跳闸线圈durable 耐用的dust catcher 粉尘吸附装置dust collecting system 粉尘收集系统DVD-ROM 光盘驱动器dyke of 岩脉dynamic balancing 动平衡dynamic stability 动态稳定性dynamometer 测力计功率计Eearthing current-return wires 接地回流导线earthing grids 接地网earthing steel flats 接地扁钢earthing switch 接地开关earthing terminal 接地端子eccentricity 偏心度eccentricity 偏心ECDC (East China Power Dispatch Center) 华东网调ECIDI (East China Investigation and 华东勘测设计研究院Designing Institute)ecologic 生态eddy current displacement transducer 涡流位移传感器eddy loss 涡流损耗eddy 涡流EDI (Electronic Data Interchange) 电子数据交换EDR (equalizing discount rate) 等值折扣率/调整贴现率education tax 教育税EIA (environmental impact assessment) 环境影响评估elasticity 弹性elasticity 椭圆率elbow 肘管electric braking device 电气制动装置electric breaking breaker 电制动断路器electric clearance 电气间隙electric fan 电动风机electric firing method 电触发方式electric gear shifting 电子换档electric interlock 电气闭锁electric output 电气输出electric quantity transducer 电量变送器electric saw 电锯electric spray valve 电动喷雾阀门electrical braking device 电气制动装置electrical contacts 电接点electrical interlock 电气闭锁electrical magnetic force 电磁力electrically independent, 单极双掷、single-pole normally-open andnormally-closed contact circuit 电气独立的接点电路electric-magnetic performance 电磁性能electro-corrosion resistant property耐电腐蚀能力electro-corrosion 电腐蚀electrolytic 电解electrolytic aluminum alloy 电解铝合金electrolytic copper 电解铜electro-magnetic environment 电磁环境electromagnetic hydraulic valve 电磁液压阀electromagnetic interference 电磁干扰electromagnetic shield 电磁屏蔽electromagnetic starter 电磁启动器electromagnetic valve 电磁阀electro-magnetic wave disturbance 电磁波干扰electromanetism compatible 电磁兼容抗扰度试验anti-interference testelectrostatic filter 静电过滤器electrostatic plate 静电板elevation of runner center line 设备安装高度of pump-turbineeligibility 合格ellipticity 椭圆度elongation 延伸embedded part 预埋件emboss 压花emergency shutdown circuit 紧急停机电路EMF (electro-magnetic flux) 电磁通量EMS (Energy Management System) 能源管理系统emulsification 乳化EN(European Standard) 欧洲标准ENAA (Engineering Advancement 日本项目促进协会Association of Japan)enamel 搪瓷珐琅encapsulate 用胶囊包装enclosed metal cubicle 封闭金属柜enclosure 外壳encoder 编码器end connector 端部接头end hoop of winding 定子绕组的端箍endanger 危及endurance duration 承受时间endurance 耐久/承受energizing pick-up type 带电动作型energy dissipation 消能English edition 英文版epidemic prevention 防疫epoxy encapsulated 环氧浇注epoxy resin 环氧树脂epoxy resin infusion capacitance type 环氧树脂浸渍电容式equalized load 平衡负荷equalizing beam 平衡梁equidistantly 等距离equilibrium 平衡平静equity investment 资本金equivalent 等值erection bay 安装间erection pedestal 安装支墩ergonomically 人类工程学erode 腐蚀escalate 逐步上升escape of oil fumes from the bearing 轴承油雾溢出essential software 基本软件ETD method 检温计法ethernet 以太网ethics 道德EUR (European EUPO) 欧元evacuation 抽出evaporation 蒸发even order harmonic voltage component 偶次谐波电压含有率even order 偶次even 均匀evenness 均匀度excitation control panel 励磁控制盘excitation cubicle 励磁柜excitation grounding detector 励磁接地探测器excitation over-voltage relay 励磁过电压继电器exciting circuit conductor 励磁回路导线execution 执行exert 发挥expansion bolts 膨胀螺栓expansion cards 扩展插件expansion joint 伸缩节expediently 方便expert system interfaces 专家系统接口expiration 期满exponential [数]指数extende 加深extension 延伸节extinguishing device 灭火装置extract active power 吸收有功extruded semi-conducting compound 挤包半导体化合物EXW (Ex factory, ex works or ex warehouse)出厂、出车间或出仓库eye ring of balancing beam 平衡梁套环excitation regulator 励磁调节器excitation system loss 励磁系统损耗excitation transformer 励磁变压器exciter transformer 励磁变excitation panel 磁盘excitation power supply 励磁电源F(empirical ) formula 经验公式（proper） frequency 固有频率3-D FEA 三维有限元fabrication 制造factice 油膏factory Acceptance Test (FAT) 工厂验收实验failure mode 容错模式fatigue (fault) 疲劳faucet 旋塞fault retrospection reviews 事故追忆fault signal 故障信号fault tolerance 容错fault treatment method 故障处理方法FCA (Free Carrier) 货交承运人FD（Flaw Detection）探伤fender-guard 防护(保险杠) ferromagnetic 铁磁ferrule 金属包头festoon 区域fiber-optic connector 光导纤维连接FIDIC (International Federation 国际咨询工程师联合会of Consulting Engineers)field erection 现场安装field pole 磁极field test 现场试验field 磁场filtration 过滤final two years 最后两年finance indicator 经济指标financing 融资findings 调查结果finite element method 有限充分价位finite element method 有限充分价位fire-extinguishing 消防fire-retardant 阻燃firewall 防火墙FIRR (Finance Internal Return Rate) 财务内部收益率first-pole-to-clear 首相开断系数fissure 裂缝fitting 附件fixture 固定体flake （成）薄片flame-retard 阻燃flange 法兰flashing circuit 起励flashover. 闪烙flaw 缺陷flexible connection 软连接flexible fixing 挠性固定flicker 闪烁float gauge 液位计floating point calculation 浮点运算能力floppy disk driver 软盘驱动器flow production method 流水作业法flowmeter 流量计fluctuation 波动flush 冲洗flush-type 嵌入式flux 焊药FOB (Free on Board) 装运港船上交货FOR (forced outage ratio) 强迫停运率formality 手续formula 公式fortify 防御forward voltage drop 正向压降foundation 基础foundation bolt 基础螺栓fracture 碎frame wall 机座壁francis 混流frequency transducers 频率变送器frequency 频率fret 使发热front-end fee 启动费frontispiece 插页FRR (fault retrospection reviews) 事故追忆Fs （safety factor）保安系数full wave 全波full-face steel lining 全断面钢衬full-graphic color VDU 彩色显示器functional keyboard 功能键盘fundamental wave 基波fuses 熔断器Ggable 山墙gall 擦伤galvanize 电镀galvanized steel structure 镀锌钢结构gang 联动gantry 门架gapless arrestor shunted with 与电容器并联的无间隙避雷器capacitorgas pipe 油管gas protection 瓦斯保护gas relay 气体继电器gasket 垫片gateways 远动网关gauge 规,计,表,样板gauge 标准尺、量表GCB (generator circuit breakers) 发动机出口断路器GCC(General Conditions of Contract) 通用合同条款gear operation mechanism 联动操作机构GECH II (General Electric Canada Hydro International Inc) GECI (General Electric Canada Inc)GECII (General Electric Canada International Inc)GEEN (General Electric Energy)generation surplus 窝电generator 发电机generator mode 发电工况generator terminal voltage overshoot 发电机机端电压超调量generator voltage circuit equipment 发电机电压设备generator/motor circuit breaker 发电电动机断路器控制开关control switchgenerator/motor-transformer block 发电电动机-变压器单元geometrical 几何的geomorphology 地貌geotextile filter 滤土工布gland 密封压盖glare 弦光glossary 汇编glossy 有光泽的got rid of from 排除govern 服从government sponsored social 社会统酬insurance fundgovernor pressure oil pipes 调速器压力油管路GPS 卫星同步时钟系统(satellite synchronizing clock system)grace period 宽限期gradation(grade) 级配grade ability 爬坡grain orientation 晶粒方向grand Canal 大运河granite 花岗岩granite porphyry 花岗岩graphical interface support 图形界面支持graphical station 图形站gravity center 重心gravity moment 重力矩gravity retaining wall 重力挡水墙graze 擦伤groove 企口groove 坡口grotto 洞ground fault current 接地故障电流grouser 履带齿片GSI (Geological Strength Index) 地质强度指标guide bearing 导轴承guide bearing loss 导轴承损耗guide bearing pad 导轴衬瓦gully-originated depression 沟源凹地gushe 涌HHalogen 卤素hand compressed air driller 手风钻hand-cart switch 手车式开关handhole 手孔hardened and tempered 调质hard-fill dam 硬填坝hardness 硬度hardware 硬件hardwired link 硬布线连接harmonic analyzer 谐波分析仪harmonic wave test 谐波试验harmonic 谐波harmoniously 和谐地harness 治理harsh class 严酷等级harsh 严酷hatch 吊物孔head cover 顶盖headrace tunnel 引水洞heartfelt thanks 忠心感谢heat endurance lever 耐热水平heat sink 散热器heat-dissipating area 散热区域heat-dissipating 散热hereinafter the same 下同hexagon 六角hierarchical 分层等级high pressure oil lifting device 高压油顶起装置high strength punched thin steel sheet 高强度薄钢板冲片hot standby 热备用hot-dip galvanizing 热浸锌hub 轮彀humidity 湿度hydraulic hoist 液压启闭机hydraulic packing 液压、密封hydraulic thrust 水推力hydraulic wrench 液压扳手hydrogeology 水文地质hydrology 水文hydropower 水电hystersis 迟后hollow 空心homogeneous 均匀homogeneous 同类的、均匀的homologous to 相似horizontal acceleration 水平加速度hot set test 热延伸特性试验hot spot oil temperature 热点油温hoisting 起吊holder rack 支架holding company 控股公司high-conductance 热导性hoist 卷扬机high voltage neutral bushing 高压中性点套管IIBRD (International Bank for 国际复兴开发银行Reconstruction and Development)ICC (International Chamber of Commerce) 国际商会IDA (International Development Association) 国际开发协会ideal 理想identical 相同一致identification system 标识系统identification 区别IFB (Invitation for Bids) 招标邀请imitative operation test 模拟动作试验immune to 不受影响免除immunity 免除免疫impact 冲击impact 影响impair 损害妨碍影响impaired mode 容错impedance 阻抗impedance protection relay 阻抗保护继电器impedance voltage 阻抗电压impedance 阻抗impede 妨碍impeller 叶轮impending 迫近imperative 迫切imperfection 缺陷impervious（blanket）防渗（阻漏毡）implementation 实施impregnate 充填饱和impregnate 充填impulse withstand voltage 雷电冲击耐受电压In the light of 由于inadequate 不充足inaugurated 就职典礼incandescent 白炽的incidental 附带incineration 烧尽焚化火葬inclined cable shaft 电缆斜井inclinometers 倾斜仪inclusions 夹杂income tax 所得税incoming line circuit breaker 进线断路器inconsistent/consistent 不一致/一致increment 增量increments 增加incur 招至损失indemnify …….against（from）保护..避免indemnity 赔偿independent duplicate 独立双调节通道regulating channelindex 指标indispensable for 必不可少的indispensable 不可缺少的，必不可少的indoor 户内induced current 感应电流induced voltage 感应电压induced 诱发inductance 电感industrial television monitoring system工业电视监视系统inertia (GD2) 惯性inevitable 不可避免inferior to 次于infiltration 渗透infinite 无限inflation 膨胀率infrared temperature detector 红外线测温仪infrared 红外线infringement 违反ingress 进入inherent 固有inhibit 禁止initial corona discharge voltage 起晕电压initial cost estimate 投资估算initial 最初initiating 起动inlet line 进线inlet valve body 进水阀阀体inlet valve pressure oil pipes 进水阀压力油管路inlet valve rotor 进水阀活门inlet valve sealing ring 进水阀止水环inlet valve servomotor cylinder 进水阀接力器缸体inlet valve servomotor piston 进水阀接力器活塞inlet valve shaft 进水阀轴inner circulating type with runner self pumping镜板泵内循环方式inner stator circumference 定子内圆innovate 创新改革inquiry/inquire 查寻inside-bridge wiring connection 内桥接线in-situ 自然位置，原位置insolvency 破产inspection window 观察窗institutional 职能instruction to applicant 申请人须知instrument 仪器insulation 绝缘insulation oil 绝缘油insulation resistance 绝缘电阻insulation strength 绝缘强度insulation withstand voltage test 绝缘耐受电压insulator 绝缘子intact 未经受损的intangible and deferred assets 递延和无形资产integral 积分integrity 完整性intelligent 智能型intensity 强度interbeds 夹板intercalated with 夹intercepting trenches 截洪沟interchangeable 可互换的interchangeable 互换interconnect 互连interface 接口interim operating 临时运行interlock 闭锁interlocking circuit 闭锁电路interlocking device 闭锁装置intermediate floor 中间层ITB (Instructions to Bidders) 投标者须知iron core loss 铁芯损耗iron core tooth pressing plat 铁芯齿压板iron core lamination 铁芯片isolated phase enclosed bus 离相封闭母线isolated phase enclosed bus bar 离相封闭母线isolated phase enclosed busbar of main circuit主回路离相封闭母线irreversible 不可逆irrevocable 不可撤消inundation 淹没inventory 库存inventory 财产目录实物盘存inversing 转换inverted field discharge 逆变灭磁inverter 逆变器intrinsic frequency 固有频率J(3-boom hydraulic) jumbo (三臂)凿岩机(anti-)jamming (防)卡(contraction) joint 伸缩缝jacking pads 顶起垫jacking 千斤顶jeopardize 危害jig 装配架夹具journal 日记、轴颈JPEPC(Jiangsu Provincial Electric Power Company)江苏省电力公司JPPC（Jiangsu Province Pricing Bureau）江苏省物价局JSPDC (Jiangsu Provincial Power Dispatch Center )江苏网调JVA (Joint Venture Agreement) 合资协定JVC (joint voltage control) 组电压控制isolated phase enclosed busbar 离相封闭母线IT(information technology) 信息技术interposing relay 中间继电器interposing （relays）中间（继电器）intuitively 直觉intersection angle 夹角intrinsic 固有内在的intrusion 侵入Kkerosene 煤油key 键key way broach 键槽拉刀keyboard 键盘kind affect 实物影响kick-off meeting 碰头会L"Limited Slip" rear axle 防滑后桥in lieu of 替代label 标志labyrinth ring 止漏环ladder 梯子lagging 滞后laminated silicon steel sheet 硅钢叠片lamination (factor) 叠压(系数) lamination segments of the rim (扇形)磁轭冲片LAN (Local Area Network) 局域网land (ac)requisition 征地large scale integrated circuit 大规模集成电路laser printer 激光打印机lash 捆绑latch 锁lateral 横向侧面latitude 行动或言论自由LAU(Launcher Unit)Layout 布置LCD(Liquid Crystal Display)LCGEP(Least Cost Generation Expansion Plan)最低价支付计划LCU (local control unit) 现场控制单元leading power factor mode 进相leading power factor 进相工况leading wire 引线leakage current test 泄漏电流测定legend 图例legible 醒目length of antenna feeder 天线馈线长度liability 负债life projection 寿命预测lift ring 吊环lifting lug 吊耳lighting equipment 照明设备light color and matt-paint 浅色无光漆limit switch 限位开关line voltage 线电压line voltage wave form distortion factor线电压波形畸变率lines of credit 信贷资金link 连接器liquid assets 流动资金liquid level transducer 液位变送器liquidate 清算liquidated damages 违约金literature 文字litho logical Units 岩性litigation 诉讼。

九年级英语社会热点话题讨论练习题30题

九年级英语社会热点话题讨论练习题30题1<背景文章>Artificial intelligence (AI) is rapidly changing our lives. In the future, AI will have an even greater impact on our daily lives. AI-powered robots will be able to perform tasks that are currently done by humans. For example, they will be able to clean our homes, cook our meals, and take care of our elderly. AI will also revolutionize the way we work. Many jobs that are currently done by humans will be automated, and new jobs will be created that require skills in areas such as programming and data analysis.The development of AI also raises some concerns. Some people worry that AI will take over too many jobs and lead to unemployment. Others worry that AI will become too powerful and pose a threat to humanity. However, many experts believe that AI can be used for good. For example, it can be used to solve some of the world's most pressing problems, such as climate change and poverty.As we move into the future, it is important to consider the potential impact of AI on our lives. We need to ensure that AI is developed and used in a way that benefits humanity.1. What can AI-powered robots do in the future?A. Only clean our homes.B. Only cook our meals.C. Take care of our elderly and perform other tasks.D. Do nothing.答案：C。

VQD1000-TF2Z545EN 4口气阀系列说明书

Instruction Manual 4 Port Solenoid ValveSeries VQD1000The intended use of this valve is to control the movement of an actuator.1 Safety InstructionsThese safety instructions are intended to prevent hazardous situations and/or equipment damage. These instructions indicate the level of potential hazard with the labels of “Caution,” “Warning” or “Danger.” They are all important notes for safety and must be followed in addition to International Standards (ISO/IEC) *1), and other safety regulations. *1)ISO 4414: Pneumatic fluid power - General rules relating to systems. ISO 4413: Hydraulic fluid power - General rules relating to systems.IEC 60204-1: Safety of machinery - Electrical equipment of machines. (Part 1: General requirements)ISO 10218-1: Robots and robotic devices - Safety requirements for industrial robots - Part 1: Robots.• Refer to product catalogue, Operation Manual and Handling Precautions for SMC Products for additional information. • Keep this manual in a safe place for future reference.CautionCaution indicates a hazard with a low level of risk which, if not avoided, could result in minor or moderate injury.WarningWarning indicates a hazard with a medium level of riskwhich, if not avoided, could result in death or serious injury.DangerDanger indicates a hazard with a high level of risk which, ifnot avoided, will result in death or serious injury.Warning• Always ensure compliance with relevant safety laws and standards.• All work must be carried out in a safe manner by a qualified person in compliance with applicable national regulations.• If this equipment is used in a manner not specified by the manufacturer, the protection provided by the equipment may be impaired.Caution• The product is provided for use in manufacturing industries only. Do not use in residential premises.2 Specifications2.1 Valve specifications TypeStandard single Large-flow single Large- flow latchingFluid Air Operating pressure range [MPa] 0 (Vacuum: -101.2 kPa) to 0.7 Ambient and fluid temperature [°C] -10 to 50 (no freezing) Flow characteristics Refer to catalogue Response time [ms] Refer to catalogue Duty cycle Contact SMC Min. operating frequency 1 cycle / 30 days Max. operating frequency [Hz] Contact SMC Manual override Non-locking push type Locking Lubrication Not required Impact / Vibration resistance [m/s 2]Note 1)150/30 Enclosure (based on IEC60529) IP402 Specifications - continuedMounting orientation Unrestricted WeightRefer to catalogueTable 1.Note 1) Impact resistance: No malfunction occurred when it was tested with a droptester in the axial direction and at right angles to the main valve and armature; in both energized and de-energised states and for every time in each condition. (Values at the initial period).Vibration resistance: No malfunction occurred in a one-sweep test between 45 and 2000 Hz. Tests are performed at both energized and de-energized states in the axial direction and at right angles to the main valve and armature. (Values at the initial period).2.2 Solenoid specifications Type Standard single Large-flow single Large-flowlatchingCoil rated voltage [VDC] 12, 24 24 Electrical entry L/M plug connector Coil insulation class Class B or equivalentAllowable voltage fluctuation-10% to +10% of rated voltage Power consumption [W] Note 1) 2 3.2 (Inrush) 1 (Holding)2Surge voltage suppressor Varistor Diode Varistor Indicator light LEDTable 2.Note 1) Refer to catalogue for energy saving type power waveform.2.3 Pneumatic symbolSingle type Latching typeFigure 1. Pneumatic symbol2.4 Special productsWarningSpecial products (-X) might have specifications different from those shown in this section. Contact SMC for specific drawings.3 Installation3.1 InstallationWarning• Do not install the product unless the safety instructions have been read and understood. 3.2 EnvironmentWarning• Do not use in an environment where corrosive gases, chemicals, salt water or steam are present.• Do not use in an explosive atmosphere.• Do not expose to direct sunlight. Use a suitable protective cover.• Do not install in a location subject to vibration or impact in excess of the product’s specifications .• Do not mount in a location exposed to radiant heat that would result in temperatures in excess of the product’s specifications. 3.3 PipingCaution• Before connecting piping make sure to clean up chips, cutting oil, dust etc.• When installing piping or fittings, ensure sealant material does not enter inside the port. When using seal tape, leave 1 thread exposed on the end of the pipe/fitting.• Tighten fittings to the specified tightening torque. Port Thread Tightening torque [N·m]1(P), 3(R) M5 1 to 1.5 2(B), 4(A)P(1), R(3) (Manifold)1/83 to 5Table 4.3 Installation - continued3.4 LubricationCaution• SMC products have been lubricated for life at manufacture, and do not require lubrication in service.• If a lubricant is used in the system, refer to catalogue for details. 3.5 Air supplyWarning• Use clean air. If the compressed air supply includes chemicals, synthetic materials (including organic solvents), salinity, corrosive gas etc., it can lead to damage or malfunction.Caution• Install an air filter upstream of the valve. Select an air filter with afiltration size of 5 μm or smaller. 3.6 Manual overrideWarning• Regardless of an electric signal for the valve, the manual override is used for switching the main valve. Since connected equipment will operate when the manual override is activated, confirm that conditions are safe prior to activation.• Locked manual overrides might prevent the valve responding to being electrically de-energised or cause unexpected movement in the equipment.• Refer to the catalogue for details of manual override operation. 3.7 MountingCaution• Ensure gaskets are in good condition, not deformed and are dust and debris free.• When mounting valves ensure gaskets are present, aligned and securely in place and tighten the mounting screws to a torque of 0.18 to 0.25 N∙m.• When piping and mounting valves, clamp the body part in place to avoid applying force to the coil. If you apply force over 120 N to coil, connection pins deform, which may cause malfunction. (Latching: 50N or more).Figure 2.3.8 Electrical circuitsCautionFigure 3. Single type (Standard: 2W)Figure 4. Single type (Large flow: 3.2 W)Effective energizing time for the energy saving type is between 15 to 25 ms at 24 VDC. Refer to catalogue for electrical power waveform.3 Installation - continuedFigure 5. Latching solenoid typeFigure 6. Positive commonFigure 7. Negative common3.9 Electrical connectorsCautionFigure 8. How to use plug connectorPull lead wire with gently, otherwise it may cause contact failure ordisconnection.Refer to catalogue for guidance on how to use plug connector. 3.10 Residual voltageCaution• If a varistor voltage suppressor is used, the suppressor arrests the back EMF voltage from the coil to a level in proportion to the rated voltage.• Ensure the transient voltage is within the specification of the host controller.• Contact SMC for the varistor residual voltage.• In the case of a diode, the residual voltage is approximately 1 V.• Valve response time is dependent on surge suppression method selected.ORIGINAL INSTRUCTIONSFittingCoilPin BodyLEDSOL.Red (+/-)Black (-/+)V a r i s t o rRed (+)Black (-)E n e r g y s a v i n g I CDiode SOL.SOL.LEDA (-) SetC (+) COMV a r i s t o rS i m u l t a n e o u s e n e r g i s a t i o n p r o t e c t i o n c i r c u i tB (-) ResetS i m u l t a n e o u s e n e r g i s a t i o n p r o t e c t i o n c i r c u i tS i m u l t a n e o u s e n e r g i s a t i o n p r o t e c t i o n c i r c u i tBlack (-) A-ONRed (+) COMWhite (-) B-ONRed (+) A-ONBlack (-) COMWhite (+) B-ONSOL.SOL.CoverGroove PinConnectorLeverLeverConnectorL plug connector M plug connector Base mounted Body ported Base mounted Body ported AC3 Installation - continued3.11 Countermeasure for surge voltageCaution•At times of sudden interruption of the power supply, the energy stored in a large inductive device may cause non-polar type valves in a de-energised state to switch.•When installing a breaker circuit to isolate the power, consider a valve with polarity (with polarity protection diode), or install a surge absorption diode across the output of the breaker.3.12 Extended period of continuous energizationWarning•If a valve will be continuously energized for an extended period of time, or is mounted in a control panel, the temperature of the valve will increase due to the heat generated by the coil assembly. This will likely adversely affect the performance of the valve and any nearby peripheral equipment. Therefore, if the valve is to be energized for periods of longer than 30 minutes at a time or if during the hours of operation the energized period per day is longer than the de-energized period, we advise using a direct operated continuous duty type valve such as the VK series or the VT series, or consider use of the latching type for which continuous energization is not required.•Coil temperature may get high due to ambient temperature or energizing duration. Do not touch the valve by hand directly. When there is such a dangerous case to be touched by hands directly, install a protective cover.•The latching type should not be energized over 30 seconds. Ensure the de-energised period is longer than the energised time (both A andB should be turned off.) before the next operation.3.13 Effect of back pressure when using a manifoldWarningUse caution when valves are used on a manifold, because an actuator may malfunction due to back-pressure.3.14 Latching typeCaution•Use in a circuit that does not have simultaneous energization of A-ON and B-ON signals.•The minimum energization time required for self-holding is 50 ms. •Although there is no problem for normal operations and environments. please consult SMC when operating in an environment with vibration (10G or more) or strong magnetic fields.•When there is the magnetic body at the valve side, it may cause malfunction. Allow a space over 10 mm between the valve and magnetic body.•Even though this valve is held on to B-ON position (passage: P → B), it may switch to the set position during transportation or due to impact when mounting valves, etc. Therefore, check the initial position by means of power supply or manual override prior to use.Energisation Passage Light colourA-ON (Set) A(-) C(+)Black RedP→A(B→R)RedB-ON (Reset) B(-) C(+)White RedP→B(A→R)GreenTable 5.Note) For positive common.4 How to OrderRefer to catalogue for ‘How to Order’.5 Outline DimensionsRefer to catalogue for outline dimensions.6 Maintenance6.1 General maintenanceCaution•Not following proper maintenance procedures could cause the product to malfunction and lead to equipment damage.•If handled improperly, compressed air can be dangerous. •Maintenance of pneumatic systems should be performed only by qualified personnel. 6 Maintenance - continued•Before performing maintenance, turn off the power supply and be sureto cut off the supply pressure. Confirm that the air is released toatmosphere.•After installation and maintenance, apply operating pressure andpower to the equipment and perform appropriate functional andleakage tests to make sure the equipment is installed correctly.•If any electrical connections are disturbed during maintenance, ensurethey are reconnected correctly and safety checks are carried out asrequired to ensure continued compliance with applicable nationalregulations.•Do not make any modification to the product.•Do not disassemble the product, unless required by installation ormaintenance instructions.6.2 MountingCautionRefer to 3.7 Mounting for guidance on how to mount valve to base.6.3 Maintainable partsCautionRefer to catalogue for how to order manifold accessories, sub-plates orelectrical connector assemblies.7 Limitations of Use7.1 Limited warranty and disclaimer/compliance requirementsCautionRefer to Handling Precautions for SMC Products.7.2 Effect of energy loss on valve switchingWarningSingle type Latching type Note)Air supply present,electrical supply cutValve spoolreturns to OFFposition by springforce.Valve spool holds position untilreset signal is sent (B-ON), spoolthen returns to OFF position byspring force.Electrical supplypresent, air supply cutValve operation is not dependent on presence of airsupply. Spool position/movement is unaffected byloss of air supply.Note) Refer to 3.14 and catalogue for Latching type operation guidance.7.3 Holding of pressureWarningSince valves are subject to air leakage, they cannot be used forapplications such as holding pressure (including vacuum) in a system.7.4 Cannot be used as an emergency shut-off valveWarningThis product is not designed for safety applications such as anemergency shut-off valve. If the valves are used in this type of system,other reliable safety assurance measures should be adopted.7.5 Leakage voltageCautionEnsure that any leakage voltage caused by the leakage current when theswitching element is OFF causes ≤ 2% of the rated voltage across thevalve.7.6 Low temperature operationCautionUnless otherwise indicated in the specifications for each valve, operationis possible to -10˚C, but appropriate measures should be taken to avoidsolidification or freezing of drainage and moisture, etc.7 Limitations of Use - continued7.7 Vacuum applications and use as a 3 port valve.Caution•Use a VQD(1/2)(2/3/5)1(V/W) valve for vacuum applications.•Connect the vacuum source to the 3(R) port.•Refer to catalogue for diagram.•Air pressure cannot be applied to the 3(R) port.•When used as a 3 port valve, conversion from N.O. to N.C. and viceversa is possible by plugging either port 4(A) or 2(B).•The valve cannot be used as a 2 port valve.8 Product DisposalThis product shall not be disposed of as municipal waste. Check yourlocal regulations and guidelines to dispose this product correctly, in orderto reduce the impact on human health and the environment.9 ContactsRefer to or www.smc.eu for your localdistributor/importer.URL : https:// (Global) https:// www.smc.eu (Europe)SMC Corporation, 4-14-1, Sotokanda, Chiyoda-ku, Tokyo 101-0021, JapanSpecifications are subject to change without prior notice from the manufacturer.© 2022SMC Corporation All Rights Reserved.Template DKP50047-F-085M。

威海何以“能”？

独家策划SPECIALWhy Is Weihai “Capable”?文／陶相银2023年11月1日11时45分，随着国网威海供电公司下达操作指令，国内在建单体容量最大海上风电项目——半岛南U场址海上风电项目一期工程接入电网运行。

至此，威海首个海上风电项目成功并网。

预计到2025年威海市新能源发电装机容量将达到1170万千瓦，占比80%，形成投资过千亿级的新能源产业集群。

深化新旧动能转换、建设绿色低碳高质量发展先行区，是党中央、国务院赋予山东的光荣使命。

威海长期坚持生态立市、绿色发展且拥有依山傍海的独特资源禀赋，有条件也有责任在发展新能源产业、推动能源绿色低碳转型上打头阵、当先锋，争当山东新能源产业布局重地、先进技术高地、东电西送要地。

山东文登抽水蓄能电站时刻保持“蓄能状态”。

图／胡红日Wendeng Pumped Storage Power Station in Shandong maintains its “energy storage state” at all times.全省唯一集齐“核风光储”全国首个固定式长桩基海上光伏实证科研项目——山东文登HG32海上光伏实证科研项目成功离网发电；省内装机规模最大的抽水蓄能电站——山东文登抽水蓄能电站全面发电；华能石岛湾高温气冷堆示范工程双堆满功率运行……作为全省唯一集齐“核风光储”新能源种类的地级市，威海新能源正在呈现出“风”生“水”起“核”裂变遍地开花态势。

新能源既是先行区建设的重要产业板块，也在为高质量发展提供源源不断的“绿色动力”。

威海把“积极融入全省绿色低碳高质量发展先行区建设”写入政府工作报告，将新型能源体系建设作为实现“双碳”目标的重要支撑，把新能源产业集群列为该市第八大产业集群，成立能源建设工作专班、新能源产业专班，出台《威海市新能源产业集群高质量发展三年行动计划（2023—2025年）》，依托规划建设的荣成核电、乳山海上风电等基地，在新能源发电项目建设中，同步开展产业链招商和产业培育。

The low-energy nuclear density of states and the saddle point approximation

a r X i v :n u c l -t h /0107074v 1 30 J u l 2001The low-energy nuclear density of states and the saddle point approximationSanjay K.Ghosh ∗and Byron K.Jennings †TRIUMF,4004Wesbrook Mall,Vancouver,British Cloumbia,Canada V6T 2A3(February 8,2008)The nuclear density of states plays an important role in nuclear reactions.At high energies,above a few MeV,the nuclear density of states is well described by a formula that depends on the smooth single particle density of states at the Fermi surface,the nuclear shell correction and the pairing energy.In this paper we present an analysis of the low energy behaviour of the nuclear density of states using the saddle point approximation and extensions to it.Furthermore,we prescribe a simple parabolic form for excitation energy,in the low energy limit,which may facilitate an easy computation of level densities.21.10.-k,21.10.Ma,26.50.+xI.INTRODUCTIONOne of the important ingredients in the Hauser-Feshbach approach to the calculation of nuclear reaction rates important for astrophysical interest is the nuclear density of states [1].In fact uncertainties in the nuclear density of states is a leading cause of errors [1]in these calculations.The studies of nuclear level densities dates back to the 1950s.with work by Rozenweig [2],and Gilbert and Cameron [3,4].The usual technique is to calculate the partition function and then invert the Laplace transform using the saddle point approximation.At energies suﬃciently high for shell and pairing eﬀects to be washed out the density of states is given in terms of the single particle density of states at the Fermi surface (and its derivatives)the shell correction energy and pairing energy.Most statistical model calculations use the back shifted fermi gas description [4].Monte-Carlo shell model calculations [5]as well as combinatorial approaches [6]show excellent agreement with this phenomenological approach.At lower energies the results are more problematic and typically crude extrapolations from the higher energy are used.In this paper we study the nuclear level density with an emphasis on the lower energy region,using a single particle shell model.The dependences in the two regimes are rather diﬀerent.In contrast to higher energies,where the density of states depends on the shell correction and the smooth single particle density of states,in the lower energy regime the density of states depends on the separation of single particle levels and their degeneracy.Moreover,at very low energy the saddle point approximation itself breaks down.We show that in this region the correction suggested by Grossjean and Feldmeier [7]gives dramatic improvements.In the next section we review the saddle point approximation in the context of nuclear level density calculation.We use thermodynamic identities to rewrite the equations in simpler form compared to the usual ones [8].Furthermore,we discuss the possible ways to simplify the evaluation of level densities at low energies.A temperature dependent parabolic equation for excitation energy seems to be a good choice.The corrections suggested [7]and the corresponding modiﬁcations to the equation are discussed in section 3.Finally in section 4we discuss our calculation and the results.II.THE SADDLE POINT APPROXIMATIONThe grand canonical partition function for two type of particles can be written as:e Ω= N ′,Z ′,E ′exp(αN N ′+αZ Z ′−βE ′)(2.1)where the sum is over all nuclei with N ′neutrons,Z ′protons and over all energy eigenstates E ′.τ=β−1,is thetemperature and µN (Z )=αN (Z )∗Email :sanjay@triumf.ca †Email :jennings@triumf.cae Ω=N ′,Z ′dE ′ρ(E ′,N ′,Z ′)exp(αN N ′+αZ Z ′−βE ′)(2.2)where ρ(E ′,N ′,Z ′)is the nuclear density of states.It represents the density of energy eigenvalues for the nucleus (N ′,Z ′)at the energy E ′.The above equation also shows that the grand partition function can be considered a Laplace transform of the nuclear density of states.The inversion integral is:ρ(E ′,N ′,Z ′)=1dβ=−E ;dΩ′d αZ=Z .(2.4)The path of the integration can be chosen to pass through this point.By expanding the exponent S in Taylor series about the saddle point and retaining only the quadratic terms,the nuclear density of states in the saddle point approximation can be written as:ρ=e Sdβ2d 2S dβdαZ d 2S dα2N d 2S dβdαZd 2Sdα2Z(2.6)To simplify the above determinant we change the independent variables to τ=1/β,µN =ταN ,and µN =ταZ and change the dependent variable to Ω′=τΩ=τS +µN N +µZ Z −E .In terms of the new variables the equations determining the saddle point are:d Ω′d µN=−N;dΩ′dτdN dτdS dµN dZ dµZdNdµZ(2.8)In deriving this result we have used the fact that in a determinant addition of a multiple of row (column)to another row (column)does not change the value of the determinant.In the ﬁrst row the derivatives are at constant µN and µZ ;in the second at constant τand µZ ,and the third at constant τand µN .The variables which are held constant can be changed using the following equations:dS dτ NZ +dS dτ µN µZ +dS dτ µN µZ(2.9)dSdNτZdNdZτNdZdSdNτZdNdZτNdZdNτZtimes the second column anddSdτNZdN dµZ dZdµZ(2.12)This procedure can be repeated to yield:D =−τ5dSdµN τZdZ aE wherea =πg/6.The temperature is τ=πaE ]g 1g 2exp[(ǫ1−ǫ2)/(2τ)]/τ.This goes to zero exponentially fast as τgoes to zero.Note that in neither of the cases above shell correction is involved.The above discussion is useful since S is a function of the energy.Here again one may use a few trick.It turns out to be easier to parameterize E as function of τ.Since τdS =dE ,one can write S = τ01dτ′dτ′+S (τ=0).The last term is the integration constant and is given once the degeneracy of the ground state is known.It contributes to exponent but not to the denominator where derivatives are taken.Next one needs E as a function of τ.For many systems there is a quite reliable approximation.For very low temperature,much less then the level spacing,the energy does not change signiﬁcantly.However above some critical temperature ,τ0,it starts to increase rapidly.For temperature nears this region the energy can be parametrized quite simply byE −E 0=c (τ−τ0)2θ(τ−τ0)(2.14)We have checked this approximation using a simple shell model and found that it works quite well except if there are more then one level approximately equal distant from the Fermi surface.The parameters τ0and c depend on the level spacing and degeneracy near the Fermi surface.Again they do not depend on the shell correction.Before being useful at very low energies a short-coming of the saddle point approximation must be overcome.It is well known that at low energies the saddle point approximation tends to diverge as the denominator goes to zero,In many cases this problem can be ﬁxed by using a technique from ref.[7]which handles the contribution to the nuclear density of states from the ground state delta function explicitly.III.MODIFIED SADDLE POINTIn ref.[7]Grossjean and Feldmeier have proposed a modiﬁcation of the saddle point method to remove the diver-gences of the level density at the ground state.Introducing explicitly the ground state energy E g(A)as the lower boundary,the density of state becomes˜ω(E∗,A)=ω(E∗+E g(A),A)−δ(E∗)δ(A−A0)(3.1) where E∗=E−E g is the excitation energy and A0is the mean particle number.The corresponding modiﬁed grand canonical potential is given by,˜Ω=Ω+βEg+ln(1−Y)(3.2) whereY=d0eαN N+αZ Z−βE g−Ω(3.3)The chemical potentials for neutrons and protons are given byµZ=αZβrespectively,d0being theground state occupancy.The nuclear level density in the modiﬁed saddle point approximation becomes,ρ=˜SdτNZ˜dN dµZτµN(3.5)The derivation of eq.(3.5)is straightforward as it depends only on the thermodynamic relations of the quantities involved and not on their explicit forms.The computation of the level density using eq.(3.4)will depend on the relations between the usual and the modiﬁed thermodynamic quantities as the usual quantities are directly related to the single particle shell model states.The modiﬁed saddle point conditions in terms of the usual thermodynamic potential becomes,dΩdβα0,β0=−(E g+˜E∗)(3.6)where˜E∗=E∗(1−Y)(see eq.(3.3)).Forα=αN(Z),A=N(Z).The derivatives of the entropy and numbers are related as,˜dSdτN,Z−β3E∗2Y+β3E∗2Y2)×1dµNτ,Z=dN−1+Y ˜dZdµZτ,N×1IV.DISCUSSIONThe single particle energies,required for the evaluation of diﬀerent thermodynamic quantities are obtained for the Nilsson shell model.The values of the constants associated with l2and l.s are taken from ref.[9].Here it should be mentioned that the level densities are strongly dependent on the single particle energy levels.Hence for astrophysical applications one should make a judicious choice for the model as well as the constants.Weﬁrst calculate the level densities for diﬀerent nuclei,for both the usual as well as modiﬁed saddle point approx-imations,using all theﬁlled and a equal number of unﬁlled levels.It should be noted the for low excitation energies (of the order ofﬁrst excitation level or less)the inclusion of only the lastﬁlled and theﬁrstﬁlled level,as described in section2,is suﬃcient for the evaluation of the level densities.A comparison of the level densities from eq.(2.3)and eq.(3.4)for nuclei32S,88Sr and208P b are shown inﬁg.1,ﬁg.2andﬁg.3respectively.The modiﬁed saddle point results are shown by curve(a)and the usual saddle points results are shown by curve(c)in the aboveﬁgures.As evident from the graphs the usual saddle point does show a divergence at the low energies whereas modiﬁed version goes to zero smoothly.This is due to the fact that entropy in the modiﬁed version goes to zero much faster as it takes into account the nonavailability of states below the ground state energy.Moreover,at low energies the diﬀerences are more pronounced for the lighter nuclei like32S compared to208P b.The diﬀerences can be attributed to the fact that in modiﬁed prescription the thermodynamic potential gets an additive contribution compared to the usual one as shown by eq.(3.2).As discussed in section2.we try toﬁt the excitation energies with parabolic form as given in eq.(2.14).Theseﬁts for diﬀerent nuclei are shown inﬁg.4,ﬁg.5andﬁg.6respectively.Inﬁgures(4-6)we have plotted the variation of excitation energy with temperature.For low energies,theﬁtted value is in good agreement with exact values.Next we calculate the entropy and its derivative,using the steps given in section2,from thisﬁtted expression for excitation energy,the derivatives of N and Z being the same as in preceding ing these we calculate the level densities for diﬀerent nuclei.A comparison of the level densities from the full calculation from modiﬁed saddle point approximation(curve(a))and the one usingﬁtted excitation energies(curve(b))are shown inﬁg.1,ﬁg.2andﬁg.3.It is obvious from the graphs that theﬁtted excitation energy gives a better agreement with exact calculation for heavier nuclei.To conclude,we have shown that the modiﬁcation of the saddle approximation is necessary for the correct evaluation of the level densities at lower energies.One can simplify the equations substantially using the thermodynamic identities.Furthermore,a parabolic prescription for the excitation energy may be useful for easier computation of the level densities.More work in this direction is needed to make the methodology useful for direct application to astrophysical reactions.0.02.04.0 6.08.010.0Excitation energy (MeV)0.02.04.06.08.0L o g (r h o )(a)(b)(c)FIG.1.Level density for 32S ;(a)modiﬁed saddle point,(b)corresponds to the ﬁtted excitation energy as in ﬁg.4and (c)usual saddle point.The vertical dashed line gives the position of 1st excitation level0.02.04.0 6.08.010.0Excitation energy0.02.04.06.08.010.012.014.0L o g (r h o )(a)(b)(c)FIG.2.Level density for 88Sr ;(a)modiﬁed saddle point,(b)corresponds to the ﬁtted excitation energy as in ﬁg.4and (c)usual saddle point.The vertical dashed line gives the position of 1st excitation level0.02.04.0 6.08.010.0Excitation energy0.04.08.012.016.020.0L o g (r h o )(a)(b)(c)FIG.3.Level density for 208P b ;(a)modiﬁed saddle point,(b)corresponds to the ﬁtted excitation energy as in ﬁg.4and (c)usual saddle point.The vertical dashed line gives the position of 1st excitation level0.00.51.01.52.0Temperature (MeV)0.02.04.06.08.010.0E x c i t a t i o n e n e r g y (M e V )(a)(b)FIG.4.Excitation energy for 32S ;(a)actual excitation energy nd (b)corresponds to the ﬁtted form eq.(2.14)with E 0=5.62and τ0=0.110.00.20.50.8 1.0Temperature (MeV)0.02.04.06.08.010.012.0E x c i t a t i o n e n e r g y (M e V )(a)(b)FIG.5.Excitation energy for 88Sr ;(a)actual excitation energy nd (b)corresponds to the ﬁtted form eq.(2.14)with E 0=15.71and τ0=0.140.000.250.500.75 1.00Temperature (MeV)0.05.010.015.020.025.0E x c i t a t i o n e n e r g y (M e V )(a)(b)FIG.6.Excitation energy for 208P b ;(a)actual excitation energy nd (b)corresponds to the ﬁtted form eq.(2.14)with E 0=40.0and τ0=0.2011。

翻译2

我国电站燃煤锅炉尾部受热面大多沿用传统的蒸汽吹灰的方式，这种传统的吹灰方式虽然应用了很长时间，但是这种方式在实际的应用中还是会产生不少的问题，如前面提到的由于疏水不充分或吹灰系统结构设计不合理导致的蒸汽带水的问题，以及对于灰中含CaO、Na2O、K2O等碱金属氧化物高的煤种，吹灰过程中带入的蒸汽使得尾部烟道的湿度增大，导致灰中的CaO、Na2O、K2O与水分发生反应生成了粘性很强的Ca(OH)2、NaOH、KOH等氢氧化物的问题；在一定的温度条件下，Ca还会和烟气中的SO2氧化成SO3后形成的硫酸作用生成硬度比较大的硫酸钙（CaSO4），造成积灰和堵灰现象。

从根本上来说，粘结性积灰都是因为烟气中湿度太大造成的，所以，如何降低烟气中的湿度是减轻尾部受热面积灰、堵灰的关键应用激波吹灰器对锅炉尾部受热面的积灰进行清理是一项比较新的技术，这项技术虽然在上个世纪二十年代就有人提出，但是直到九十年代末期才开发成功应用于燃煤电厂锅炉的吹灰，其原理是可燃气体按一定比例与空气混合后形成预混气体，预混气体在特别设计的湍流燃烧室中点火快速发生燃烧反应，并在爆炸罐中加速产生高速脉冲射流，最后经喷口向受热面发射脉冲球面波及高速射流，使受热面上的积灰受到强烈的脉冲球面波激振和高速射流的冲刷而脱落，最后由烟气带走。

从改造前后测得的数据可以看到，改装激波吹灰器后，锅炉的排烟温度比改装前下降了3～9℃，说明改为激波吹灰器后，尾部受热面的热交换有所改善，表明尾部受热面比改造前清洁，激波吹灰的清灰效果明显。

在停炉后尾部受热面的检查中，也发现与改造前的受热面情况相比，管子表面上的灰垢大为减少，特别是那种粘结性强的灰垢基本不存在，热交换管的表面上只是一些比较松散的积灰。

本文第一章主要阐述了电煤在我国未来能源结构中的地位，着重介绍了神华煤在我国电煤市场中的重要性以及其在电厂锅炉中燃烧的特点，对神华煤作为电厂锅炉燃煤的优缺点进行了评价。

简单的介绍了一下国内外对煤质与结渣和积灰、堵灰倾向性的研究方法和为防止结渣和积灰、堵灰采取的对策，并对目前我国电厂锅炉运行中防止结渣和积灰、堵灰技术的研究状况做了介绍。

对熄灯的看法英语作文初一

As a junior high school student,you might be asked to write an essay on your views about turning off lights.Heres a structured approach to help you craft a thoughtful essay:Title:My Perspective on Turning Off LightsIntroduction:In todays world,where energy conservation is a global concern,the simple act of turning off lights is more than just a personal habit its a statement of environmental responsibility. As a junior high school student,I believe that this seemingly small action can have a significant impact on our environment and our future.Body Paragraph1:Awareness of Energy ConsumptionThe first step towards embracing the practice of turning off lights is to understand the extent of our energy consumption.In our daily lives,we often take for granted the convenience of flicking a switch to bring light into our spaces.However,the electricity used to power these lights contributes to a significant portion of our carbon footprint.By being mindful of when and how we use lights,we can reduce our energy consumption and contribute to a more sustainable lifestyle.Body Paragraph2:The Impact on the EnvironmentTurning off lights when they are not in use is a simple yet effective way to reduce our environmental impact.The energy saved from this practice can be redirected towards more sustainable sources,such as renewable energy projects.Moreover,reducing our reliance on nonrenewable energy sources like coal and oil can help in mitigating the effects of climate change,which is a pressing issue that affects us all.Body Paragraph3:The Role of Education and CommunityEducation plays a crucial role in promoting the habit of turning off lights.Schools,like the one I attend,can incorporate energy conservation lessons into their curriculum to instill these values in students from a young age.Additionally,community initiatives that encourage residents to participate in energysaving practices can create a collective effort towards a greener future.Body Paragraph4:Personal Responsibility and ActionsAs individuals,we have a personal responsibility to contribute to the cause of energy conservation.Turning off lights when they are not needed is a simple action that each of us can take.Beyond that,we can also advocate for energyefficient lighting solutions, such as LED bulbs,which consume less energy and last longer than traditional bulbs. Conclusion:In conclusion,the practice of turning off lights is not just about saving electricity its about taking a stand for a healthier planet.Its a small step that each of us can take to make a big difference.As a junior high school student,I am committed to spreading awareness about the importance of energy conservation and encouraging my peers to join me in this endeavor.Remember to write in a clear and concise manner,using simple language that is appropriate for your grade level.Good luck with your essay!。

译林版高中英语学案选择性必修第四册精品课件 UNIT 3 Section A

Para.2
B.Work contributes to the health of society.
Para.3
C.There are other important reasons that motivate us to enter
the world of work besides earning a living.
wyer n.律师→ law
n.法律
4.receptionist n.接待员→ reception n.接待;招待会
5.respective adj.分别的,各自的→ respect n.方面;敬意;尊敬 v.尊敬,
尊重
6.operate vt.操作,使运行 vi.运转,工作;经营,营业→ operation n.操作;
单元
文化意识
1.了解不同职业的特点、价值及意义,树立正确、积极的职业观, 培养职场意识; 2.树立正确的劳动观。弘扬中华民族的勤劳美德,创造美好生活。
素
1.帮助学生掌握未来职业发展趋势,培养对不同职业的尊重和理
养思维解;
目品质 2.启发学生思考个人职业倾向和未来规划,促进学生的自我成长
标
respective
operate hire
receipt commercial weekly monthly
client detective subjective plug
premier qualificationswing
label
applicant prior
criterion shave
mode delay
元必 leadership
素语言背 budget loan
养能力单 groundwork

1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。

a r X i v :h e p -t h /9903024v 1 2 M a r 1999Low-Energy Eﬀective Actionin N=4Super Yang-Mills TheoryI.L.Buchbinder Department of Theoretical Physics,Tomsk State Pedagogical University,Tomsk 634041,Russia Abstract:We consider N =4supersymmetric Yang-Mills theory formulated in terms of N =2superﬁelds in harmonic ing the background ﬁeld method we deﬁne manifestly gauge invariant and N =2supersymmetric eﬀective action depending on N =2strength superﬁelds and develop a general procedure for its calculation in one-loop approximation.Explicit form for this eﬀective action is found for the case of SU (2)gauge group broken down to U (1).Maximally extended N =4supersymmetric Yang-Mills (SYM)theory attracts much attention due to remarkable properties on quantum level and profound links with modern string/brane activity.It is natural to expect that an eﬀective action describing many aspects of quantum theory,such as symmetry breaking,low-and high-energy behaviour,anomalies and so on,also must possess the many remarkable features in N =4SYM.Unfortunately,the eﬀective action of N =4SYM was studied unsuﬃciently so far andones know little both about its general structure and about its form in diﬀerent approxi-mations.One of the main obstacles to investigate the eﬀective action in N =4SYM is absence of adequate quantum formulation such a theory.In our opinion,an eﬃcient technique of carring out the calculations of eﬀective action in N =4SYM preserving N =4supersymmetry manifestly is still undeveloped.The best we have at present is treatment of N =4SYM as N =2SYM coupled to a speciﬁc (hypermultiplet)matter and use the methods of N =2supersymmetric quantum ﬁeld theory.Recently Dine and Seiberg [1]has shown that part of low-energy eﬀective action of N =4SYM depending only on N =2superﬁeld strengths W and ¯Wcan be found exactly up to numerical factor on the base of restrictions imposed by N =4supersymmetry.To be more precise,it was shown that low-energy eﬀective action Γ[W,¯W ]for N =4SU (2)theory is expressed in terms of non-holomorphic eﬀective potential H (W,¯W)as follows Γ[W,¯W]= d 4xd 8θH (W,¯W )(1)whereH(W,¯W)=c log ¯W2Λ2(2)with some numerical coeﬃcient c and some scaleΛ.The eﬀective action(1)with H(W,¯W) (2)isΛ-independent.The explicit calculation of the coeﬃcient c have been given in Refs [7,8].The generalizations for arbitrary SU(n)groups were considered in Refs[9,10].The present paper is a brief overview of the approach to calculation of low-energy eﬀective action in N=4SYM developed in Refs[8,9].We consider N=4SYM formulated in terms of N=2superﬁelds in harmonic superspace[2].Such an approach is still the only one operating with unconstrained N=2 superﬁelds and explicitly realizing SU(2)R-symmetry of N=2Poincare superalgebra. Manifestly N=2supersymmetric calculation of low-energy(holomorphic)eﬀective action in harmonic superspace was given in Refs[3,4,6].From point of view of N=2supersymmetry,the N=4SYM theory describes coupling of N=2vector multiplet to the hypermultiplet in the adjoint representation.In harmonic superspace approach,the vector multiplet is realized by an unconstrained analytic gauge superﬁeld V++[2]and hypermultiplet can be realized either by real unconstrained analytic superﬁeldω(ω-hypermultiplet)or by a complex unconstrained analytic superﬁeld q+(q-hypermultiplet)[2].In theω-hypermultiplet realization,the action of N=4SYM theory readsS[V++,ω]=12g2dζ(−4)tr∇++ω∇++ω(3)In the q-hypermultiplet representation,the N=4SYM theory is given by the actionS[V++,q+,˘q+]=12g2dζ(−4)tr q+i∇++q i(4)q+i=(q+,˘q+),q+i=εij q+j=(˘q+,−q+)Both models(3,4)are manifestly N=2supersymmetric.However,they possess the two extra hidden supersymmetries[2]and,as a result,ones get N=4supersymmetric theories with N=4SYM content.Of course,the theories(3,4)are classically equivalent.Our purpose is to describe a calculation of low-energy eﬀective action for the above theories.Theﬁrst step of calculation is backgroundﬁeld quantization of the model under con-sideration allowing to preserve manifest gauge invariance and N=2supersymmetry. Backgroundﬁeld formulation for N=2supersymmetricﬁeld theories in harmonic su-perspace was developed in Ref[4](see also[5,6]).Within this formulation,the one-loop eﬀective actionΓ(1)[W,¯W]for the theories(3,4)looks likeΓ(1)[W,¯W]=i2Tr(4,0)log⌢2(5)where⌢2is the analytic d’Alambertian introduced in Ref[4]and the formal deﬁnition of the Tr(2,2)log⌢2and Tr(4,0)log⌢2are given in Ref[8].The second step is convenient path integral representation of the eﬀective action Γ(1)[W,¯W]for special background.The low-energy eﬀective action(1)depends only on W¯W,therefore it is suﬃcient to choose the background gauge superﬁeld on shellDα(i D j)αW=0(6)where D iαare the standard N=2supercovariant derivatives.In this case the eﬀective action(5)can represented in the formexp(iΓ(1)[W,¯W])= D G++exp −iD G++exp −i2d8z tr¯V∆V(9)∆=D a D a−eWαDα+e¯W˙α¯D˙α+e2|φ|2Here D a,Dα,¯D˙αare the N=1supercovariant derivatives andΓ(1)depends onφ,Wα,¯φ,¯W˙α,V and¯V are unconstrained N=1complex scalar superﬁelds.Theﬁnal step is calculation ofΓ(1)(9)in low-energy limit.We consider the background gauge superﬁeld corresponding to the unbroken U(1)subgroup of SU(2)group in the Coulomb branch.In this case the eﬀective actionΓ(1)depending onφ,¯φ,Wα,¯W˙αcan be written as followsΓ(1)= d8zWαWα¯W˙α¯W˙α∂4H(φ,¯φ)se−i(e2|φ|2−iε)s d8z U(z,z|s)(11) where for constant W and¯W ones obtainU(z,z′|s)=i4is(12)It leads to∂4H(φ,¯φ)/∂φ2∂¯φ2=(4π¯φφ)−2(13) One can easilyﬁnd a general solution of this equation and restore the function H(W,¯W).Weﬁnally getH(W,¯W)=1Λ2log¯W2To conclude,we have formulated a general procedure of calculating the low-energy eﬀective action depending on N=2strength superﬁelds for N=4SYM theories. AcknowledgementsI am grateful to S.M.Kuzenko for fruitful collaboration and to E.I.Buchbinder,E.A. Ivanov and B.A.Ovrut for numerous discussions.The work was supported in part by RFBR grant,INTAS grant,project N o96-0308,RFBR-DFG grant,project N o96-02-00180,GRACENAS grant,project N o97-6.2-34.It is pleasure to thank the Organizing Commettee of the Buckow Symposium for the warm hospitality.References[1]M.Dine,N.Seiberg,Phys.Lett.B409,239,1997.[2]A.Galperin,E.Ivanov,S.Kalitzin,V.Ogievetcky,E.Sokatchev,Class.Quant.Grav.1,469,1984;A.Galperin,E.Ivanov,V.Ogievetcky,E.Sokatchev,Class.Quant.Grav.2,601;617,1985.[3]I.L.Buchbinder,E.I.Buchbinder,E.A.Ivanov,S.M.Kuzenko,B.A.Ovrut,Phys.Lett.B412,309,1997;E.I.Buchbinder,I.L.Buchbinder,E.A.Ivanov,S.M.Kuzenko, Mod.Phys.Lett.A13,1071,1998.[4]I.L.Buchbinder,E.I.Buchbinder,S.M.Kuzenko,B.A.Ovrut,Phys.Lett.B417,61,1998.[5]I.L.Buchbinder,S.M.Kuzenko,B.A.Ovrut,Phys.Lett.B433,335,1998.[6]I.L.Buchbinder,Eﬀective action of N=2supersymmetricﬁeld theories in harmonicsuperspace approach,Proc.Second Int.Conf.“Quantum Field Theory and Grav-ity”,Tomsk,1998,pp.41-52,hep-th/9802155;I.L.Buchbinder,B.A.Ovrut,Back-groundﬁeld method and structure of eﬀective action in N=2super Yang-Mills the-ories,in“Theory of Elementary Particles”,Proc.31st Int.Symposium Ahrenshoop, 1997,Buckow,Wiley-Vch,1998,pp.33-39,hep-th/9802156;I.L.Buchbinder,S.M.Kuzenko,B.A.Ovrut,Covariant harmonic supergraphity for N=2super Yang-Mills theories,hep-th/9810040.[7]V.Periwal,R.von Unge,Phys.Lett.B430,71,1998;F.Gonzalez-Rey,M.Roˇc ek,Phys.Lett.B434,303,1998.[8]I.L.Buchbinder,S.M.Kuzenko,Mod.Phys.Lett.A13,1623,1998.[9]E.I.Buchbinder,I.L.Buchbinder,S.M.Kuzenko,Phys.Lett.B446,216,1999.[10]F.Gonzalez-Rey,B.Kulik,I.Y.Park,M.Roˇc ek,Self-dual eﬀective action of N=4super Yang-Mills,hep-th/9810152;D.A.Love,R.von Unge,Constraints on higher derivative operators in maximally supersymmetric gauge theory,hep-th/9811017. [11]I.L.Buchbinder,S.M.Kuzenko,Ideas and methods of supersymmetry and super-gravity,IOP Publ.,Bristol and Philadelphia,1995;Revised edition1998.。