Need the masses of unstable particles and their antiparticles be equal in the CPT--invarian
杂说练习题
一、文学常识1. 《红楼梦》的作者是谁?2. 《三国演义》中谁被称为“卧龙”?3. 《西游记》中唐僧师徒四人分别是谁?4. 《水浒传》中梁山好汉共有多少人?5. 《骆驼祥子》的作者是谁?二、文言文阅读1. 下列句子中,哪一句是出自《论语》?a. 己所不欲,勿施于人。
b. 学而时习之,不亦说乎?c. 三人行,必有我师焉。
d. 人无远虑,必有近忧。
2. 下列词语中,哪一个是出自《庄子》?a. 鹏程万里b. 神龙见首不见尾c. 朝三暮四d. 破釜沉舟3. 下列句子中,哪一句是出自《孟子》?a. 得道多助,失道寡助。
b. 非礼勿视,非礼勿听,非礼勿言,非礼勿动。
c. 人之初,性本善。
d. 己所不欲,勿施于人。
4. 下列词语中,哪一个是出自《诗经》?a. 桃之夭夭,灼灼其华。
b. 春风得意马蹄疾,一日看尽长安花。
c. 人生得意须尽欢,莫使金樽空对月。
d. 床前明月光,疑是地上霜。
三、现代文阅读1. 下列文章中,哪一篇文章是鲁迅的作品?a. 《背影》b. 《荷塘月色》c. 《故乡》d. 《背影》2. 下列词语中,哪一个是出自朱自清的作品?a. 美不胜收b. 烟花三月下扬州c. 水天一色d. 风花雪月3. 下列句子中,哪一句是出自茅盾的作品?a. 世间万物皆有毒,唯有爱不可挡。
b. 人生如梦,岁月如歌。
c. 人生自古谁无死,留取丹心照汗青。
d. 人生得意须尽欢,莫使金樽空对月。
4. 下列词语中,哪一个是出自巴金的作品?a. 美不胜收b. 烟花三月下扬州c. 水天一色d. 风花雪月四、诗词鉴赏1. 下列诗句中,哪一句是出自唐代诗人杜甫的作品?a. 春风得意马蹄疾,一日看尽长安花。
b. 人生得意须尽欢,莫使金樽空对月。
c. 会当凌绝顶,一览众山小。
d. 床前明月光,疑是地上霜。
2. 下列诗句中,哪一句是出自宋代诗人苏轼的作品?a. 春风得意马蹄疾,一日看尽长安花。
b. 人生得意须尽欢,莫使金樽空对月。
c. 会当凌绝顶,一览众山小。
核能专业英语
核能专业英语公司内部档案编码:[OPPTR-OPPT28-OPPTL98-OPPNN08]第一课词汇:•Concept概念, conception概念, conceive构想、理解•Isotope同位素, isomer同质异能素•element, atom, nucleus, nucleon–element, elements,–molecule, molecules, molecular–atom, atoms, atomic,–nucleus['nju:klis,'nu:klis]原子核, nuclei, nuclear,–nucleon['nju:klin]核子, nucleons, nucleonic核子的–particle, particles,•fissile易裂变的, fissionable可以发生裂变的•fertile可裂变的,fertile materials增殖材料•fission, fusion, decay•inner, innermost / outer, outermost•chain reaction•fragment碎片Expression:•times–A is ten times B.•varies inversely as•E equals m times c squared. E = mc2•the n-th power of a: an•result in / result from•is accompanied by / correspond to•The discovery of fission was made in Germany in 1938 by Hahn......•Be composed of 由…组成•Binding energy 结合能•Discrete excited states 不连续的激发态•Electromagnetic radiation 电磁辐射•Ev:electron-volt•Conservation of mass/energy 质量/能量守恒练习:•电子带负电,质子带正电。
核电专业英语课件解析1-3单元
核电专业英语 · 课件解析(工程人员用)p为什么要学习这本书?ü了解最新研究成果和新技术(来源于美英法等国——英文发表)ü阅读需要(研究、设计、工程、运行、维修等人员——阅览英文原版)ü集团“走出去”的需要(国际会议、国外工程等的直接参与者)ü论文发表需要(工作需要)ü... ...核材料03核反应堆理论04核反应堆概念05(核反应堆)热工水力06核物理的基本概念01辐射02压水堆冷却剂系统的主要部件09压水堆系统与安全壳10汽轮机11主蒸汽、给水与冷凝水系统12反应堆压力容器与堆内构件堆芯与核燃料08压水堆07核电厂的运行13西屋公司的AP1000非能动压水堆欧洲压水堆(EPR)17重水堆18第四代核电技术19辐射风险与屏蔽14核安全152016010*******词汇——掌握核反应堆物理、热工、反应堆设备和原理相关的英文专业词汇写作——掌握一定的英文写作专业文章的基本技巧语法——掌握常见英文专业文献的语法结构阅读——掌握阅读和理解专业英文文献的技巧和方法短语——掌握常用的短语固定搭配p 培训目的学习方法预习环节1)熟悉词汇;2)了解关键词解释;3)了解Self-test的内容;4)了解课文注释;5)熟悉课文(标记每个段落的主要知识点)。
复习环节1)掌握要求熟记的词汇;2)掌握关键词汇及其习惯用法,以及衍生词汇及常用搭配,并学会举一反三;3)熟悉惯用语法结构,并学会举一反三;4)温习课文,巩固行业基本常识,快速、准确地完成Self-test内容。
Contents for TodayUnit 1 核物理的基本概念•原子与原子核•同位素•质量亏损•结合能•能级•裂变Unit 2 辐射•放射性•电子激发与电离•原子与的重电荷粒子的减速•原子核引起的重电荷粒子的散射•Ɣ射线与物质间的相互作用•α、β、Ɣ射线的特性Unit 3 核材料•燃料•慢化剂•冷却剂•包壳材料•控制材料Unit 1The Basic Concepts for Nuclear Physics核物理的基本概念Unit 1-关键词汇及常用搭配(一)1. configuration(结构、配置,侧重配置和外形)- structure(侧重内在结构)- arrangement(布局、分布)2. constituent(组成的)-------近义:component动词:constitute(组成、构成)- institute(制定、设立)e.g. constituent nucleons===component nucleonse.g. Volunteers constitute more than 95% of the Center's work force.3. (be) curious about(对...感到好奇,想了解)e.g. Steve was intensely curious about the world I came from.4. decay(衰变) - decay heat(衰变热)- decay coefficient(衰变系数)...5. deficiency(缺乏、不足)- Deficiency in N / N deficiencye.g. Deficiency in vitamins/Vitamin deficiency can lead to illness.e.g. Many children in the poor area had calcium deficiency.**deficient - be deficient in6. discrepancy(矛盾、差错、不符)- difference (in)(差异、区别、不同)e.g. This discrepancy will prevent me from obtaining a visa.7. dormant(固定的、休眠的、静止的)- at rest(静止的)- activee.g. an active / dormant volcano8. glance(一瞥、环顾)** take/have a glance of / glance at - look at(看)- stare/glare at(盯着看,凝视)9. macroscopic(宏观的)- microscopic(微观的)10. moderation(慢化) - moderator (慢化剂)11. permeation(渗透、穿透)- penetration(渗透)12. repulsion(排斥)- attraction(吸引)13. as far as(就...、至于...、据...)- as long as(只要...)e.g. They returned at nine last night, as far as we know.e.g. I will cooperate as long as I am notified on time.** as far as sb/sth be concerned(就...而言,对...来说)e.g. As far as I am concerned, I agree with the latter opinion.e.g. As far as balance construction materials are concerned, both aluminum and steel may be used.14. more or less(有点、或多或少、大概)- about(前置)- or so(后置) - approximatelye.g. It's an hour's ride more or less from here to the center of the city.15. tend to(趋于、倾向于、助于、留心、关照)Unit 1 - 课文基础知识点1Atoms and Nuclei1.Atoms of all elements consist of three fundamental particles: protons, neutrons andelectrons---more fundamental(基本的).2. A atom consists of a nucleus at the center and electrons in the moving orbitsaround it.3.The arrangement of these particles within the atom, and in particular the number ofprotons and electrons determine the chemical identity of the element.4.The nucleus is formed with protons and neutrons being grouped together(定语后置).5.Protons are positively charged, electrons are negatively charged, while neutronsare electrically neutral.p In a neutral or unionized atom, the No. of protons Z is equal to the No. of electrons, this number Z is the atomic number of a given element.p The sum of the number of neutrons and protons in the nucleus is called the mass number: A =Z+N2Isotopes1.A toms having the same atomic number Z, but different numbers of neutrons N arecalled isotopes of that element identified by Z.(定语后置)2.All elements have a number of isotopes, in some cases 20 or more.3.Naturally occurring elements have one or more stable isotopes, and the otherisotopes are unstable or radioactive, which can be produced artificially.(定语从句)4.Different isotopes are chemically identical because they belong to the same element,but physically different, e.g. different mass….plete identification of an isotope is made by giving its chemical symbol, theatomic number Z as a subscript and the mass number A as a superscript, e.g. 16O, 17O, 18O, .6.Hydrogen is an important element in nuclear :p1H---hydrogenp2H---heavy hydrogen, also called deuterium (氘)p3H---super-heavy hydrogen, also called tritium(氚)p Only case that different isotopes have different names.3Mass Defect1.The mass of atom is not equal to the sum of the masses of its constituent particles.2. E.g. the mass of 16O atom is obviously less than the sum of the masses of 8neutrons and 8 hydrogen atom (8 protons and 8 electrons) .3.The principle of mass conservation appears to be violated.4.The difference between the mass of an atom and the sum of the masses of itsconstituent particles is known as the mass defect.5.The explanation is to be found in the principle of the equivalence of mass andenergy, Einstein stated that mass and energy are two different forms of the same fundamental quantity, E=mc2.6.In many reactions there is an interchange of mass and energy, particularly on anatomic scale. The laws of mass conservation is no longer valid and must be replaced by the laws of conservation of mass and energy.7.So, a decrease of mass is accompanied by the release of energy, and an increase ofmass corresponds to the absorption of energy.4Binding Energy1.The force of electrostatic repulsion between like charges, which varies inversely asthe square of their separation, would be expected to be so large that nuclei could not be formed .2.That they do exist means there is an even larger force of attraction - nuclear force(核力).3.Nuclear force acts only when the nucleons are very close and binds them into acompact stable structure.p The net force is a potential energy of binding, to disrupt a nucleus into its component nucleons, energy must be supplied from the outside.p A given nucleus is lighter than the sum of its separate nucleons, the difference being the binding mass-energy.p The binding energy B =ΔMC2, ΔM=total mass of separate particles minus mass of the atom.5Energy Levels1.N ormally nuclei exist in an equilibrium or stable state condition known as groundstate of energy.2.As a result of nuclear reaction, e.g bombardment of atoms by protons, neutrons orother particles, nuclei can be produced in an excited or unstable condition - called excited state.3.Such excited states or levels in a nucleus are similar to the excited state of atoms.•I n general light nuclei have more widely spaced excited levels and in all nuclei the spacing (能级差) of the levels decreases as the excitation energy increases.•Most excited nuclei exist in this state for only a very short time, typical average lifetime being about 10-14 seconds.•They decay or become de-excited by the emission of high-energy electromagnetic radiation known as gamma radiation, or particles such as neutrons or both.6Fission (to be continued)1.Fission was discovered in Germany in 1938, the process involved the bombardmentof uranium by neutron.2.In the process uranium nucleus split into two fragments which were themselvesnuclei of intermediate mass elements.3.It was shown that neutrons were also emitted in the process and the possibility of achain reaction was realized, in which neutrons emitted in one fission event might be able to cause further fission, thus establishing a continuous reaction.(表语从句)4.The isotopes of uranium include:•Uranium-235 , is basically responsible for fission, occurring only to the extent (abundance) of 0.715 %, fission can be caused by neutrons of any energy, low energy neutrons being the most effective.•Uranium-238, comprises 99.285 % of natural uranium, fission can only be caused by neutrons of energy greater than 1 MeV .5.There are three other isotopes of importance which can undergo fission: thorium钍-232 (Th-232), uranium-233 and plutonium-239.6Fission (Continued)6.The energy released is due to the mass loss after the reaction, about 0.1% of theoriginal mass is converted into energy.7.For each kilogram of Uranium, fission energy is equivalent to the energy availablefrom 3000 tons of coal.8.Only small part of natural uranium can be burned in the fission, however the energypotential of uranium can be increased about 100-fold by conversion of the non-fissile 238U into fissile material, namely plutonium-239 ( 239Pu ).9.The fission can be easily caused by low-speed neutrons, although fast neutron caninteract with 235U, the chance is rare, more fission can be caused if the velocity of neutron can be reduced to 2 km/s, these neutrons are often called thermal neutron.p Nuclear reactor using the fast neutron are called fast reactors.p Those using the slower neutrons are termed thermal reactors.p The process when fast neutrons are converted into thermal neutrons as a result of a series of collision with surrounding atoms is called thermalization or moderation which will be discussed in later units.Unit 1-关键词汇及常用搭配(四)16. consist of (由...组成、包含)近义1:be made up of / be composed of 近义2:constitute (组成,构成)1.1e.g. Search engines consist of 3 main parts.17. positively charged (protons) - uncharged (neutrons) - negatively charged (electrons)1.118. the principle of conservation of mass = the law of conservation of mass(定律、原理)1.219. 用法相同而意思相对的词语:positively charged ---- negatively charged 1.1equal to(相同)---- opposite to(相反)1.1release(释放) of energy ---- absorption(吸收) of energy 1.2decrease(减少) of mass ---- inrease(增加) of mass1.2like charges(同性电荷)---- unlike charges(异性电荷)1.4repulsion(排斥)---- attraction(吸引) 1.4ground state(基态)---- excited state(激发态) 1.5kinetic energy(动能)---- potential energy(势能) 1.6**active(能动的)----passive(非能动的)(后续章节)Unit 1-关键词汇及常用搭配(五)20. 同种意思的不同表达:be accompanied by(伴随)=== correspond to(对应,伴随)1.2Normally = In general = As a rule(一般来说,通常)1.5known as = called(称之为)1.5(be) called = (be) termed(称之为)1.6of importnance(后置定语)= important(前置定语)lighter than = less than the mass of (与....相比质量更少) 1.3e.g. A given nucleus is lighter than the sum of its separate nucleonsbe present in = be found in = exsist in (见于,存在于)e.g. A negatively charged particle which is present in every atom.与...一样:the same as(+人,物,所有格)与the same with(+代词)的区别e.g.:1) A neutral particle found in the nucleus of an atom, which has about the same mass as a proton. 1.1 2)I have the same dream as yours. 3)He was in the same factory with me.e s t S e l f-tUnit 2 Radiation辐射Unit 2-关键词汇及常用搭配(一)1. analogy(类似)- adj. analogous ---- similar2. anxiety(担心,忧虑)- adj. anxious (be anxious about)3. attenuation(衰减)- attenuation coefficient - 相近:decay, disintegration(衰变)4. bulk(大块,大多数,散装,批量,主体,大部分)e.g. in bulk(散装,大批); bulk buying(批发采购);the bulk of sth(主体,大部分)5. competion(竞争)------- e.g. competion between A and B(A和B竞争)competion in sth(在某方面的竞争)6. culminate(达到极致,结束)------- e.g. culminate in failure / in success(以----而告终)7. deduce(推论,导出)------- e.g. deduce that从句(主动语态)be derived from(被动语态)8. distinguish(区别,分类)---- e.g. distinguish A from BUnit 2-关键词汇及常用搭配(二)9. incident(入射的)---- 衍生:小事件(核电厂0级事件,Level 0 incident)10. migrate(迁移)-衍生:immigrate(迁进)----emmigrate(迁出)11. scatter(散射)- 衍生:scattering(散射)----absorption(吸收) (be anxious about)12. stationary(静止的)- 相近:at rest - 相反:moving(移动的)13. vicinity(附近)-e.g. in the vicinity (of) 在...附近14. visualize(目测,观察)-adj. visual - give sth a visual check(目视检查)15. as a rule of thumb(根据经验,一般来说)相近:as usual, usually, in general...Unit 2 - 课文基础知识点1Radioactivity (to be continued)1.Radioactivity is a common natural phenomenon, the discovery of which predatesthe discovery of nuclear fission by more than 40 years.2.It is the invisible nature of radiation that contribute to public anxiety concerningnuclear power, but it can be detected with scientific instruments.(强调句式)3.The radiation is harmful because it has ability to ionize atoms within our bodies; itmay alter the cell structure and even cause cell death in large doses.4.Also there is a risk that harmful cell mutation can survive within the body andpossibly cause various types of cancer---another public concern;5.Radioactivity is a spontaneous, natural and random process that can occur in threebasic forms known as alpha, beta and gamma decay:p Alpha radiation can carry a significant amount of energy, sufficient to do serious damage to any living tissue, but it can travel just a few centimeters of air or a piece of paper, from which the real risk is to be ingested into the lungs or the digestive system.1Radioactivity (continued)p Beta radiation can cause lower biological harm than with alpha radiation, but its penetrating power is greater, from which the potential risk can be eliminated by a sheet of perspex or a metal foil.p Gamma radiation is a very high-energy X-ray, which is extremely penetrating, and several centimeters of lead or meters of concrete are necessary to pratically shield gamma radiation.6.Radioactivity and radiation is all around us, it has been and will always be. Thedoses we get from routine radiation in medicine and dentisty may be much larger than that from living near a nuclear power plant.7.The amount of radioactivity is proportional to the number of atoms present, butwhen decay occurs the number of atoms of the radioactive isotopes remaining to decay would be reduced, and then radioactivity would also be reduced.2Excitation and ionization by electrons1.When electrons of inner orbits in heavy elements are displaced, the resultant high-energy radiation is classified as X-ray so useful for internal examination for the human body.2.Beta particles as electrons from nuclear reactions have energy in the range of0.01~1 MeV, and thus are capable of producing large amounts of ionization as theypenetrate a substance, and in the process beta particles lose energy and eventually are stopped.3.For electrons of 1 MeV energy, the typical distance of penetration is no more than afew mm in liquids and solids or a few meters in air.3Heavy charged particle slowing by atoms1.Charged particles such as protons, alpha particles or ions such as fragments offission are classified as heavy particle, much more massive than the electrons.2.For the same particle energy they have far less speed than an electron, but they areless readily deflected in their motion than electrons because of their inertia.3. A great deal of ionization is produced by the heavy ion as it moves through thematter, as a result of these interactions, the energy of heavy ion is reduced and eventually is stopped in a range that is much shorter than that for electrons.4.For example, a 2 MeV alpha particle has a range of about 1 cm in air…thereforethere is generally no protective shielding problem against alpha particle.Heavy charged particle scattering by nuclei p Charged particles such as protons, alpha particle encounter a very heavy chargednucleus, the projectile is scattered throughan angle that depends on the detailednature of the collision, i.e. the initialenergy and direction of the motion of theincoming ion relative to the target nucleus,and the magnitude of electric charge of theinteracting particles.Unit 2 - 课文基础知识点5Gamma ray interactions with matter1.There are three types of interaction between gamma rays and the matter:•Photoelectric scattering 光电散射•Photoelectric effect 光电效应•Electron-positron pair production 正负电子对产生p Photon-electron scattering,also called Comptom scattering, the photon collides with electrons, the collision may be treated by physical principle of energy and momentum conservation. In the process of photon-electron scattering, the photon is deflected and loses energy, while the electron gains energy and moves away with high speed leaving the atom ionized.p Photoelectric effect, in competition with scattering, an incident photon of high energy knocks out an electron from the atom, leaving a positively charged ion. In doing so, the photon is absorbed and thus lost.p Electron-positron pair production, in which the photon is converted into matter, entirely in accordance with equivalence of mass and energy.Unit 2 - 课文基础知识点6The properties of Alpha, Beta and Gamma radiationp Alpha particle:•Double positive charges, much heavier than electron;•Travel through matter in straight lines, cause intense ionization and lose energy rapidly;•Present no shielding problem since they move very short distance through matter, but harmful when alpha emitting isotope is ingested into the body.p Beta particle:•Emitted from a radioactive isotope with a spectrum of energies;•Interact with matter by causing ionization, but the effect is less than that of alpha;•Travel through matter in zigzag paths, not in straight lines;•penerate through 20 meters in air and 1cm in aluminum, much more penetrating than alpha particles with a similar ingestion hazard.p Gamma radiation:•Much greater penetrating power in matter than Beta particles;•Present a serious shielding problem when it is produced in large quantities, e.g. nuclear reactor to be discussed later in the chapters for radiation hazards and reactor shielding.Unit 2-关键词汇及常用搭配(三)16. be harmful to(对...有害)---e.g. Radioactivity is harmful to living tissue.* do harm to -----e.g. Smoking does harm to your health.17. by the application of(利用)-相近:by the use of18. be vulnerable to sb/sth(容易受到...的伤害)e.g. Our skin tissues are vulnerable to the suns ultraviolet rays.19. travel ... in straight lines(走直线)- 相对- travel ...in zigzag paths(走曲线)e s t S e l f-tUnit 3 Nuclear Materials核材料Unit 3-关键词汇及常用搭配(一)1. exposure to sth(暴露于,受到)-----be exposed toe.g. Continuous exposure to sound above 80 decibels could be harmful.2. fraction(分数,部分)- adj. fractionala fraction of 一小部分---------a part of 一部分3. liable(易于...倾向于...)- be liable to ---- 相近: be subject to(易受...支配,易患...)e.g. He is liable to come today.Drink driving may be liable to 48-hour prison term.e.g. My mother is very subject to headaches.The sale of firearms is subject to many legal restrictions4. scale(规模,尺度) ----in scale(按比例,规模)----on a large scale(大规模地)e.g. The building is in scale with its surroundingse.g. The government's aid programme to the Ya'an Earthquake was very large in scale.关键词Fuel---fissionable fuel to supply energy, selected on the basis of physics and economics1Moderator---slow down the fast neutrons to the thermal energy for sustain the fission process2Coolants---transfer the heat from the core to the steam generator3Cladding materials---the first barrier againstradioactivity4Control materials---neutron absorbing5Structural materials---hold the (heavy) core in place inside the reactor6Unit 3 - 课文基础知识点1Fuels (to be continued)Uranium1.Uranium in one form or another is by far the most common materials uased fornuclear reactors either as pure uranium, a metal or as a compound.2.Uranium carbide-UC, which has not been developed to the same extent as UO2, onlybe used in HTGR-high temperature gas-cooled reactors.3.The abundance of U-235 is only 0.7%, too rare to be used directly, it is necessary toconcentrate (called enrichment).•U-235 will be enriched to 3~5% for use in light water reactors;•The enrichment usually has two processes: gas diffusion and gas centrifuge;•The remaining part of Uranium become less content(<0.3%) is called depleted uranium(贫铀);•Natural uranium can be burned in heavy water reactor.1Fuels (continued)Plutonium1.Plutonium, a transuranic metal element with several isotopes, is very toxic andhighly reactive in moist air, but can be stored in dry air at low temperature.2.Pu can be used for nuclear weapons and reactors, and as a reactor fuel it is used asthe PuO2.3.PuO2 is mixed with UO2 to form MOX fuel used for fast reactors, of which theproperties are similar to those of UO2 alone.Thorium1.Thorium has not been used as a reactor fuel to any great extent yet except in a fewhigh-termperature gas-cooled reactors.2.It is not used as a fuel in its pure form, instead either as ThO2 or ThC2, but to datethey have only been used to a very small extent in a few high-temperature gas-cooled reactors.2Moderator (to be continued)1.The requirements of moderator for a thermal reactor are low mass number, very lowneutron capture cross-section and high scattering cross-section.2.Few materials are suitable choices of moderators for thermal reactors, but three, i.e.hydrogen and its isotope deuterium in the form of compounds (water and heavy water) and carbon in the form of graphite.p Water•It is an obvious choice for the moderator and the coolant of a thermal reactor due to its excellenet neutron slowing down properties.•Due to its relatively high capture cross-section, water moderated reactors require enriched U for criticality.•High pressure (typically 15~16 MPa for PWR) is required to keep water in liquid form from becoming steam.•It is important to maintain water purity to prevent corrosion and from becoming radioactive due to neutron activation.Unit 3 - 课文基础知识点2Moderator (continued)p Heavy water•It is similar to ordinary water in most of its physical and thermodynamic properties.•The main difference is that deuterium has a much lower capture cross-section than hydrogen, and that it is not as a good moderator as hydrogen.•It is necessary to use natural uranium as fuel (lower U concentration than water moderated reactors) for heavy water moderated reactors with rather larger cores than light water moderated reactor cores.•It is very expensive to produce heavy water and the leakage loss must be minimized. p Graphite•It is not as a good moderator as heavy water, but readily obtainable at reasonable cost, easily machined, and of good structural and thermal properties.•Graphite cores are assembled from large numbers of blocks, in which holes are provided for fuel and control elements;•Graphite may undergo dimensional changes due to prolonged neutron irradiation, so it must be kept away from burning at a high-level temperature.Unit 3 - 课文基础知识点3Coolant1.Many proposed coolants are light water, heavy water; gas and liquid metals.2.Both in PWR and BWR, coolant water also serves as moderator.3.Principal requirements for coolant are as follows:•good thermodynamic properties;•chemically non-reactive with other components of the reactors;•very low neutron capture cross-section.•do not become radioactive as a result of (n, γ) reactions which may occur due to neutron irradiation in core.4.In addition to water and heavy water, carbon dioxide and inert helium gas are regarded as twomost suitable gaseous coolants for gas-cooled reactors, and liquid sodium as the standard coolant for fast breeder reactors.•Carbon dioxide chosen as the coolant in British gas-cooled reactors has proved troublesome despite its advantages in many aspects.•Helium gas is perhaps the ideal gaseous coolant, but not readily available in large quantities and expensive, which is used as a reactor coolant now only in few high-temperature gas-cooled reactors.•Only liquid sodium is now regarded as the standard coolant for a few fast breeder reactors.Unit 3 - 课文基础知识点4Cladding materials1.The cladding material requires a very low neutron capture cross-section, goodthermal conductivity, good strength at high temperature to resist thermal stress, corrosion resistance, deformation of the fuel and buildup of fission gas pressure inside cladding, and easy to fabricate.2.Many materials have been tested for use as cladding material:•Berylium has not proved to be suitable material for use in reactors.•Aluminium can only be used as the cladding material for low power research reactors.•Magnesium has been extensively used as the cladding material in British gas-cooled reactors.•Zirconium and the Zircaloys are considered the preeinent fuel cladding materials at present but with explosive hazards above about 1000℃.•Stainless steel is not used as fuel cladding in PWRs, but used in the advanced gas-cooled reactors and fast breeder reactors.Unit 3 - 课文基础知识点5Control materials1.The control materials should be a highly efficient neutron absorber with a very highabsorption cross section for thermal neutrons.2.Boron, alloyed with steel or used in the form of boron carbide encased in steel, isgood at capturing thermal neutrons. It can also be used in the form of boric acid dissolved in the coolant of PWRs for reactivity control and for emergency shutdown system.3.Indium and cadmium, encased in stainless steel, are used as control rods in PWRs.4.Hafnium is an excellent control material, but too expensive to be used in large scalefor commercial reactors.Unit 3 - 课文基础知识点6Structural materials (additional)1.The structural materials serve to hold the core in place and support it during itsservice life, including some heavy components.2.The structural materials should not interfere with neutron operation of the reactors;3.The requirement for such structural materials are as follows:•of high temperature strength and low neutron absorption cross section;•must neither corrode rapidly in the primary coolant, like all other parts of the core, nor contribute to any long-life radioactive materials in the primary coolant;•should be good at resisting neutron irradiation without losing ductility, and available to carry out life-time assessment to ensure their properties are not degrade.Unit 3-关键词汇及常用搭配(二)5. easily available(容易获得)-相近:readily obtainable 3.3e.g. Helium is not readily available in largequantities and is expensive.6. provided (that) +条件状语从句(只要) 3.3e.g. Sodium is not corrosive to most structural materials provided its oxygen content is maintedlow.e s t S e l f-tp课后作业1.通读Unit 1-3课文,完成Self-test;2.翻译Unit 1-3课文基础知识点(笔头作业,下次课前交);3.掌握Unit 1-3的重要词汇及固定搭配(整理笔记);4.预习Unit 4-5。
核能专业英语
第一课词汇:•Concept概念, conception概念, conceive构想、理解•Isotope同位素, isomer同质异能素•element, atom, nucleus, nucleon–element, elements,–molecule, molecules, molecular–atom, atoms, atomic,–nucleus['nju:kli?s,'nu:kli?s]原子核?, nuclei, nuclear,–nucleon['nju:kli?n]核子, nucleons, nucleonic核子的–particle, particles,•fissile易裂变的, fissionable可以发生裂变的•fertile可裂变的,fertile materials增殖材料•fission, fusion, decay•inner, innermost / outer, outermost•chain reaction•fragment碎片Expression:•times–A is ten times B.•varies inversely as•E equals m times c squared. E = mc2•the n-th power of a: an•result in / result from•is accompanied by / correspond to•The discovery of fission was made in Germany in 1938 by Hahn......•Be composed of 由…组成•Binding energy 结合能•Discrete excited states 不连续的激发态•Electromagnetic radiation 电磁辐射•Ev:electron-volt•Conservation of mass/energy 质量/能量守恒练习:•电子带负电,质子带正电。
牛顿 万有引力定律 原文
牛顿万有引力定律原文English Answer:Newton's Law of Universal Gravitation.The law of universal gravitation, formulated by Sir Isaac Newton, describes the force of attraction between any two objects with mass. It states that every particle of matter in the universe attracts every other particle with a force that is directly proportional to the product of their masses and inversely proportional to the square of the distance between them.Mathematically, the law is expressed as:>。
> F = G (m1 m2) / r^2。
>。
where:F is the force of attraction between the two objects.G is the gravitational constant (6.674 × 10^-11 m^3 kg^-1 s^-2)。
m1 and m2 are the masses of the two objects.r is the distance between the centers of mass of the two objects.The law of universal gravitation has far-reaching applications in various fields of science, including astronomy, astrophysics, cosmology, and engineering. It explains the motion of celestial bodies, such as planets, moons, and stars, within the solar system and the universe. It is also used to calculate the force of attraction between objects on Earth, such as the weight of an object or the force between two charged particles.The law of universal gravitation is a fundamental principle of physics that has played a pivotal role in our understanding of the universe and its workings. It is a testament to Newton's brilliance and his ability to distill complex natural phenomena into simple and elegant mathematical expressions.Chinese Answer:牛顿万有引力定律。
Two-dimensional Quantum Field Theory, examples and applications
Abstract The main principles of two-dimensional quantum field theories, in particular two-dimensional QCD and gravity are reviewed. We study non-perturbative aspects of these theories which make them particularly valuable for testing ideas of four-dimensional quantum field theory. The dynamics of confinement and theta vacuum are explained by using the non-perturbative methods developed in two dimensions. We describe in detail how the effective action of string theory in non-critical dimensions can be represented by Liouville gravity. By comparing the helicity amplitudes in four-dimensional QCD to those of integrable self-dual Yang-Mills theory, we extract a four dimensional version of two dimensional integrability.
2 48 49 52 54 56
5 Four-dimensional analogies and consequences 6 Conclusions and Final Remarks
加减速下的直线惯量计算
加减速下的直线惯量计算英文回答:Calculating Rotational Inertia of a Rigid Body During Linear Acceleration.The rotational inertia of a rigid body is a measure of its resistance to angular acceleration. It is defined as the sum of the products of the masses of the particles in the body and the squares of their distances from the axis of rotation.For a rigid body undergoing linear acceleration, the rotational inertia can be calculated using the following formula:I = m r^2。
where:I is the rotational inertia.m is the mass of the body.r is the distance from the axis of rotation to the center of mass of the body.This formula can be used to calculate the rotational inertia of a rigid body undergoing linear acceleration in any direction.Example:Consider a rigid body of mass m = 1 kg and radius r = 0.5 m. The body is undergoing linear acceleration of a = 2 m/s^2. The rotational inertia of the body about an axis passing through its center of mass and perpendicular to the direction of acceleration is:I = m r^2 = 1 kg (0.5 m)^2 = 0.25 kg-m^2。
英汉翻译基础教程
英语翻译基础教程总主编:冯庆华主编:冯庆华陈科芳1 “意思”的译法甲:这是一点小意思,请务必收下。
乙:你这个人真是有意思,怎么也来这一套。
甲:哎,只是意思意思,乙:啊,真是不好意思。
译文:A:This is a little gift as a token of my appreciation .Please do take it . B:Oh, aren't you a bit too polite ? you should not do that .A: Well ,it just conveys my gratitude.B: Ah, thank you then ,though i really do not deserve it . 2 “说”(1)阿Q将衣服摔在地上,吐一口唾沫,说:“这毛虫”!《阿Q正传》译文:Ah Q flung his jacket on the ground ,spat ,and swore ,“hairy worm!”(2) “三个臭皮匠,合成个诸葛亮”,这就是说,群众有伟大的创造力。
《毛泽东选集》文: The old saying ,"three cobblers with their wits combined would equal Zhuge Liang the mastermind ,"simple means the masses have great creative power.(3):也不知安居乐业,最早见于什么典籍,四个字一针见血的点名了生活中的一个因果关系。
译文:I can not say in what canon the words "secure in one's home and happy in one's work" first appeared ,but that expression cuts to the core of a primary determinant in human life.3 你们偶然看见一颗花生瑟缩的长在地上,不能立刻分辨出它有没有果实,非得等到你接触到它时你才能知道。
重庆理工大学材料科学基础双语翻译第2章翻译-R1
Review回顾复习
Please cite引用 the four components部分 for materials 材料 science and engineering discipline工程科学.
Fundamentals of Materials Science andhemical element 化学元素is characterized by (的特点) the number of protons in the nucleus 原子核, or the atomic number (Z) (原子序数). The atomic mass (A) (原子质量) of a specific 特 殊的atom may be expressed as 被表示成the sum 总数 of the masses of大多数 protons and neutrons 中子within the nucleus. Thus atoms of some elements基础 have two or more different atomic masses, which are called isotopes (同位素).
Fundamentals of Materials Science and Engineering
What should you be able to do after studying this chapter?
Name and explain the primary or chemical bond 化学键found in向 提供 solids固体.
Fundamentals of Materials Science and Engineering
废除大规模毁灭性武器的必要性英语作文
废除大规模毁灭性武器的必要性英语作文The Necessity of Abolishing Weapons of Mass DestructionThe world has witnessed the devastating effects of weapons of mass destruction (WMDs) throughout history. From the atomic bombings of Hiroshima and Nagasaki during World War II to the ongoing threat of nuclear proliferation, the existence of these destructive forces has posed a significant threat to global peace and security. It is imperative that the international community takes decisive action to abolish WMDs and work towards a safer and more stable world.The primary argument for the abolition of WMDs is the immense humanitarian cost associated with their use. These weapons have the capacity to cause unimaginable destruction, with the potential to obliterate entire cities and populations. The long-term effects of radiation exposure can lead to devastating health consequences, including increased rates of cancer, birth defects, and environmental degradation. The psychological trauma experienced by survivors and the rippling effects on affected communities can be truly devastating.Moreover, the possession and development of WMDs come at an immense financial cost, diverting valuable resources away from morepressing social and economic priorities. Governments around the world invest billions of dollars annually in the maintenance and modernization of their nuclear arsenals, often at the expense of funding for education, healthcare, and infrastructure development. This misallocation of resources has far-reaching consequences, particularly for developing nations that could benefit greatly from increased investment in sustainable development and social welfare.The proliferation of WMDs also heightens the risk of accidental or unauthorized use, which could have catastrophic global consequences. The complexity of nuclear command and control systems, coupled with the potential for human error or technical failures, creates a constant threat of unintended detonation or escalation of conflicts. This unpredictability and lack of control over these weapons only serves to increase the urgency for their abolition.Furthermore, the existence of WMDs fuels an ongoing arms race, as nations seek to maintain a perceived strategic advantage over their rivals. This cycle of military buildup and deterrence often leads to increased tensions and the potential for armed conflict, undermining global stability and the prospects for lasting peace. The abolition of these weapons would remove this destabilizing factor and encourage a shift towards more constructive and cooperative approaches to international security.It is important to recognize that the abolition of WMDs is a complex and multifaceted challenge, requiring the coordination and cooperation of nations around the world. Achieving this goal will require a comprehensive and sustained effort, including the development of robust international treaties, strengthened verification and enforcement mechanisms, and the investment in alternative security frameworks that do not rely on the threat of mass destruction.Despite the challenges, the potential benefits of abolishing WMDs are overwhelming. A world free from the threat of these devastating weapons would pave the way for increased global cooperation, the redirection of resources towards more constructive endeavors, and the establishment of a more stable and secure international order. The pursuit of this goal is not only a moral imperative but a necessary step towards a more peaceful and sustainable future for all of humanity.In conclusion, the necessity of abolishing weapons of mass destruction is clear. The immense humanitarian, financial, and strategic costs associated with their existence far outweigh any perceived benefits. It is the responsibility of the international community to work together to achieve this critical objective, ensuring a safer and more prosperous world for generations to come.。
废除大规模毁灭性武器的必要性英语作文
The Urgency of Abolishing Weapons of MassDestructionIn the intricate tapestry of global affairs, the urgent need to abolish weapons of mass destruction stands as a paramount concern. These armaments, be they nuclear, biological, or chemical, pose a dire threat to human existence and the sustainability of our planet. Their mere existence creates a perpetual shadow of fear, casting apall over international relations and stalling progress towards a peaceful, harmonious world.The devastation wrought by weapons of mass destruction is unimaginable. Nuclear weapons, in particular, have the capacity to annihilate entire cities in a single strike, leaving behind a trail of destruction and death that extends for generations. The long-term environmental impact of such weapons is also catastrophic, poisoning the soil, water, and air, making it difficult for life to thrive.Moreover, the possession of these weapons creates a dangerous arms race among nations. Countries feel compelled to arm themselves in order to maintain a sense of security, often at the cost of ignoring more pressing issues likepoverty, hunger, and climate change. This mindset perpetuates a cycle of fear and mistrust, making itdifficult to forge meaningful partnerships and collaborations that could lead to genuine progress.The abolition of weapons of mass destruction is not only a moral imperative but also a practical necessity. It would pave the way for a safer, more secure world where nations can focus on addressing the real challenges facing humanity. It would also pave the way for the redirection of vast resources currently spent on weapons development towards more productive and beneficial pursuits like education, healthcare, and environmental protection.Achieving this goal will require concerted effort and cooperation from all nations. It will involve diplomatic negotiations, the establishment of verifiable disarmament mechanisms, and a shift in global mindset towards peace and cooperation. The international community must come together to ensure that the threat posed by weapons of mass destruction is eliminated once and for all.In conclusion, the abolition of weapons of mass destruction is a critical step towards a safer, morepeaceful world. It is an urgent task that requires the commitment and cooperation of all nations. By working together to eliminate these armaments, we can lay the foundation for a future where humanity can thrive and prosper without the constant shadow of fear and destruction. **废除大规模毁灭性武器的必要性**在全球事务的纷繁复杂中,废除大规模毁灭性武器的紧迫性已成为一个至关重要的议题。
分解质因数 英语
分解质因数英语Title: Prime Factorization: Unlocking the Secrets of NumbersIntroductionPrime factorization is a fundamental concept in mathematics that has numerous applications in various fields, from computer science to cryptography. It involves breaking down a number into its prime factors, which are the prime numbers that, when multiplied together, result in theoriginal number. This process is not only essential for understanding the properties of numbers but also haspractical implications in areas such as number theory, algorithm design, and data encryption.The Importance of Prime FactorizationPrime factorization is a crucial tool in mathematics and computer science, as it helps us understand the structure andbehavior of numbers. By identifying the prime factors of a number, we can gain insights into its divisibility, its prime factors, and its relationship with other numbers. This information can be used to solve a wide range of problems, from finding the greatest common divisor (GCD) of two numbers to designing efficient algorithms for tasks such as integer factorization.In computer science, prime factorization is particularly important in the field of cryptography. Many modern encryption techniques, such as the RSA algorithm, rely on the difficulty of factoring large numbers into their prime factors. The security of these algorithms depends on the fact that it is computationally challenging to find the prime factors of a large number, especially as the number grows in size.The Process of Prime FactorizationThe process of prime factorization involves breaking down a number into its prime factors, which are the prime numbers that, when multiplied together, result in the original number. There are several techniques that can be used to performprime factorization, including the trial division method, the factor tree method, and the Sieve of Eratosthenes.The trial division method is one of the simplest and most straightforward approaches to prime factorization. Itinvolves dividing the number by each prime number, starting with the smallest prime number, until a factor is found. This process is repeated until all the prime factors of the number have been identified.The factor tree method, on the other hand, involves creating a visual representation of the prime factorization process. The number is first divided by its smallest prime factor, and then each of the resulting factors is furtherdivided by their respective prime factors. This process continues until all the prime factors have been identified.The Sieve of Eratosthenes is a more efficient algorithmfor finding prime numbers, which can be used as a starting point for prime factorization. This method involves systematically eliminating numbers that are not prime,starting with the smallest prime number, until all the prime numbers up to a given limit have been found.Applications of Prime FactorizationPrime factorization has a wide range of applications in various fields, including:1. Number theory: Prime factorization is essential for understanding the properties of numbers, such as divisibility, prime factors, and the relationship between different numbers.2. Computer science: Prime factorization is crucial in cryptography, where it is used to design secure encryptionalgorithms. It is also used in algorithm design, where it can be used to optimize the performance of certain algorithms.3. Engineering: Prime factorization is used in the design and analysis of electrical circuits, where it can be used to identify the prime factors of the impedance of a circuit.4. Finance: Prime factorization can be used in financial modeling and analysis, where it can be used to identify the prime factors of financial data and to identify patterns and trends.5. Physics: Prime factorization is used in particle physics, where it is used to identify the prime factors of the masses of subatomic particles.ConclusionPrime factorization is a fundamental concept in mathematics that has numerous applications in various fields. By understanding the process of prime factorization and itspractical implications, we can gain insights into the natureof numbers and develop more efficient and effective solutions to a wide range of problems. Whether it's in computer science, cryptography, or any other field, the ability to performprime factorization is a valuable tool that can help usunlock the secrets of numbers and unlock new opportunitiesfor innovation and discovery.。
医学专题放射性核素的衰变规律
disintegration by which some unstable atomic nuclei spontaneously dissipate excess energy and undergo a change of one unit of positive charge without any change in mass number. • The three processes are electron emission, positron (positive electron) emission, and electron capture.
• 特征X射线或俄歇电子的能量都是单一的
• 间接证实电子俘获存在的方法或途径: 观察原子特征X射线或俄歇电子的发射
电子俘获的衰变纲图
β衰变小结
• β衰变都是同量异位素之间的跃迁
• β衰变包括β- 衰变、β+ 衰变和电子俘获(EC) • 发生β- 衰变的是丰中子的核素,而发生β+
衰变和电子俘获(EC)的是丰质子的核素
• In the most common form of gamma decay, known as gamma emission, gamma rays (photons, or packets of electromagnetic energy, of extremely short wavelength) are radiated
物理的美妙之处 英语作文
物理的美妙之处英语作文英文回答:The beauty of physics lies in its ability to unravel the mysteries of the universe, from the smallest particles to the largest galaxies. It is a discipline that combines rigorous mathematical principles with experimental observation to provide a comprehensive understanding of the natural world.One of the most profound aspects of physics is its universality. The laws of physics apply everywhere in the universe, regardless of time or location. This universality is evident in the fact that scientists can use the same equations to describe the motion of a ball on Earth as the orbit of a planet around the sun.Another remarkable feature of physics is its ability to make predictions. By understanding the fundamental laws of nature, physicists can predict the behavior of physicalsystems in a wide variety of situations. For example, physicists can use the laws of motion to predict the trajectory of a projectile or the laws of thermodynamics to predict the direction of heat flow.The beauty of physics is also evident in its simplicity. While the underlying mathematics of physics can be complex, the fundamental concepts are often remarkably simple. For example, the law of gravity can be expressed in a single equation:F =G (m1 m2) / r^2。
注意地形的英文
注意地形的英文Attention to TerrainThe terrain of the Earth's surface is a complex and dynamic system that plays a crucial role in shaping the natural environment and human activities. From towering mountains to vast plains, the diverse landscapes of our planet have a profound impact on the way we live, work, and interact with our surroundings. As we continue to explore and harness the resources of our world, it is essential that we pay close attention to the terrain and its implications for our well-being and sustainability.One of the primary reasons why terrain is so important is its influence on climate and weather patterns. The shape and elevation of the land can affect the flow of air masses, the distribution of precipitation, and the intensity of weather events. For example, mountainous regions often experience higher levels of rainfall and snowfall due to the way air masses are forced to rise and cool as they encounter the terrain. Conversely, areas with flat or gently rolling landscapes may be more susceptible to drought and extreme temperatures, as they lack the natural barriers that can moderate the effects of climate.In addition to its impact on weather and climate, terrain also plays a crucial role in the distribution and availability of natural resources. The presence of mountains, valleys, and other topographical features can determine the location and accessibility of resources such as minerals, water, and arable land. This, in turn, can shape the patterns of human settlement and economic activity, as people seek to take advantage of the resources that are most readily available in a given region.One of the most significant ways in which terrain affects human activities is in the design and construction of infrastructure. Roads, bridges, railways, and other transportation networks must be carefully planned and engineered to navigate the challenges posed by the terrain. Factors such as slope, soil composition, and drainage patterns can all have a significant impact on the feasibility and cost of constructing these essential pieces of infrastructure.Similarly, the terrain can also influence the design and construction of buildings and other structures. In areas with steep slopes or unstable soil conditions, for example, special engineering techniques may be required to ensure the safety and stability of buildings. Conversely, in flat or gently rolling areas, the terrain may allow for more flexibility in design and construction, potentially reducing the overall cost and complexity of the project.Beyond its impact on infrastructure and resource distribution, terrain can also play a crucial role in shaping the cultural and social dynamics of a region. Certain landscapes may be more conducive to the development of traditional agricultural practices, while others may be better suited for pastoralism or hunting and gathering. The terrain can also influence the way in which people interact with their environment, as well as the development of unique architectural styles and cultural traditions.In recent years, the importance of terrain has become increasingly recognized in the context of environmental conservation and sustainability. As we strive to mitigate the effects of climate change and protect the natural resources that sustain us, it is essential that we develop a deeper understanding of how terrain shapes the ecosystems and habitats that we depend on. This knowledge can inform the development of more effective land-use policies, conservation strategies, and sustainable development practices.Overall, the importance of terrain cannot be overstated. From its influence on climate and weather patterns to its role in shaping human activities and cultural traditions, the diverse landscapes of our planet play a crucial and multifaceted role in our lives. As we continue to explore and utilize the resources of our world, it is essential that we pay close attention to the terrain and itsimplications for our well-being and the long-term sustainability of our planet.。
滑坡防治工程技术方法示范及指南
滑坡防治工程技术方法示范及指南English:Landslide prevention and control engineering techniques play a crucial role in minimizing the occurrence and impact of landslides. To effectively address these natural hazards, it is essential to adopt a comprehensive approach that combines various methods and technologies. First and foremost, a thorough understanding of the geological and topographic conditions of the area is necessary. This involves conducting detailed surveys and investigations to identify potential landslide-prone zones. Once these areas are identified, engineering measures can be implemented. This may include the construction of retaining walls, slope stabilization, and surface drainage systems. Retaining walls are crucial for providing support and preventing the movement of unstable soil masses. Slope stabilization techniques such as soil nailing, rock bolting, and slope reinforcement using geosynthetics are also effective in mitigating landslides. Additionally, proper surface drainage systems should be designed to prevent excessive infiltration of water, which can increase the pore water pressure and trigger slope failure.In recent years, the use of advanced technologies has significantly improved landslide prevention and control measures. Remote sensing techniques such as LiDAR (Light Detection and Ranging) and satellite imagery can accurately identify potential landslide areas and monitor their behavior over time. This allows for early warning systems to be established and timely evacuation plans to be implemented. Furthermore, the development of geotechnical modeling software enables engineers to simulate different scenarios and assess the stability of slopes. This provides valuable insights into the performance of various landslide mitigation measures before implementation. Additionally, the integration of sensor networks can continuously monitor important parameters such as groundwater levels, soil moisture, and slope displacement, allowing for real-time monitoring and alert systems.To ensure the effectiveness of landslide prevention and control measures, it is crucial to have comprehensive guidelines and demonstration projects. These guidelines should cover all aspects of landslide hazard assessment, monitoring, and mitigation, and include best practices and technical standards. Demonstration projects can showcase the implementation and effectiveness of various landslideprevention techniques, serving as a reference for future projects. These projects should be widely disseminated to increase awareness and understanding among stakeholders and the general public. Overall, the combination of comprehensive guidelines and demonstration projects, along with the integration of advanced technologies, will significantly improve landslide prevention and control efforts, ultimately reducing the risk and impact of landslides.中文翻译:滑坡防治工程技术方法在减少滑坡的发生和影响方面起着至关重要的作用。
Alevel PH2 physics questions
Physics PH2Cardiff High SchoolQuestions PH2.1 WAVESQuestion 1 Jan ’03 PH1 Q6Question 2June ’03 PH1 Q3Question 3Jan ’04 PH1 Q7Question 4 June ’04 PH1 Q5Question 5 June ’04 PH1 Q6Question 6 June ’04 PH1 Q7Question 7 June ’05 PH1 Q3Question 8 June ’05 PH1 Q7Question 9 Jan ’06 PH1 Q6Question 10 June ’06 PH1 Q4Question 11 June ’06 PH1 Q6PH2.2 REFRACTION OF LIGHTQuestion 1Jan ’05 PH1 Q6Question 2 June ’05 PH1 Q5Question 3 Jan ’06 PH1 Q5Question 4 June ’07 PH1 Q4PH2.3 PHOTONSQuestion 1 June ’03 PH2 Q4Question 2June ’03 PH2 Q5Question 3 June ’03 PH2 Q6Question 4Jan ’04 PH2 Q4Question 5 Jan ’04 PH2 Q6Question 6 June ’04 PH2 Q6Question 7 June ’04 PH2 Q7Question 8 Jan ’05 PH2 Q1Question 9 Jan ’05 PH2 Q5Question 10 J an ’05 PH2 6PH2.4 MATTER, FORCES AND THE UNIVERSEQuestion 1 Edexcel Specimen PaperQuestion 2 E dexcel June ‘01Question 3 Edexcel Jan ‘02Question 4 Edexcal June ‘02Question 5 Edexcel June ‘03Question 6 Edexcel Jan ‘04PH2.5 USING RADIATION TO INVESTIGATE STARSQuestion 1 June ’03 PH1 Q4Question 2 Edexcel Specimen PaperQuestion 3 Edexcel Jan ‘02Question 4 Edexcel June ‘02Question 5 Edexcel Jan ‘03Question 6 Edexcel June ‘03Question 7 Edexcel Jan ‘04PH2.1 WAVES Question 1Question 2Question 3Question 4Question 5Question 6Question 9PH2.2 REFRACTION OF LIGHT Question 1Question 2PH2.3 PHOTONS Question 1Question 6Question 7Question 8Question 9Question 10PH2.4 MATTER, FORCES AND THE UNIVERSEQuestion 1(a) The strong force is one of the fundamental interactions. What exchange particleis associated with this force?.................................................................................................................................List the other fundamental interactions. Circle the one for which the photon isthe exchange particle.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(5)(b) Complete the table below which compares alpha particle scattering with deepinelastic scattering.(4)(c) The Ω– (omega minus), a particle with strangeness –3, was identified in 1964 inan experiment involving an interaction between a K– meson of strangeness –1and a proton.K– + p →Ω– + K+ + K0Is the Ω– particle a baryon or a meson? Give two reasons for your answer.....................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2)(e) The theory of relativity established that all forms of energy possess mass and,conversely, that material particles are a form of energy. If enough energy isconcentrated, new particles of matter will appear. Thus, the violent collision oftwo protons, for example, can produce more protons. Whenever matter iscreated this way in the laboratory it is always accompanied by an equivalentquantity of antimatter. Each lepton and quark possesses an antiparticle in whichall the physical properties except mass are reversed. If an antiparticle encountersits mirror particle they annihilate each other, usually in the form of gammaradiation.[Adapted from Paul Davies: The particles and forces of nature, in Revised NAS Physics,Longman 1986.](i) The collision between two protons is described as being a violentcollision. Explain why the collision must be a violent one in order toproduce more protons.........................................................................................................................................................................................................................................................................................................................................................................................................................................................................(2)(ii) Whenever matter is created “it is al ways accompanied by anequivalent quantity of antimatter”.What conservation laws does this statement imply?............................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................................(3)Question 2The grid shows the relationship between number of neutrons N and number of protonsZ for some of the stable nuclides in the region Z = 31 to Z = 45.NStrontium-90, 9038Sr, is an unstable nuclide. It decays by –emission to anunstable isotope of yttrium. On the graph mark the position of 9038Sr and this isotope of yttrium.(2)82 37Rb is another unstable nuclide. Mark the position of 8237Rb on the graph.By what means would you expect 8237Rb to decay?..................................................................................................................................(2)The following strong interaction has been observed.K– + p n + XThe K– is a strange meson of quark composition s u.The u quark has a charge of +2/3.The d quark has a charge of –1/3.Deduce the charge of the strange quark. ..................................................................................................................................(1)Use the appropriate conservation law to decide whether particle X is positive, negative or neutral. .................................................................................................................................. ..................................................................................................................................(2) Is particle X a baryon or a meson? Show how you obtained your answer. .................................................................................................................................. ..................................................................................................................................(2)State the quark composition of X. Justify your answer. .................................................................................................................................. .................................................................................................................................. .................................................................................................................................. .................................................................................................................................. ..................................................................................................................................(3)。
宇宙学和理论物理中的基本问题
2)暗物质
1933年,Zwicky就提出了暗物质的概念。 1968年,Silk(Silk damping, 密度涨落消失) 1974年起,更多的观测证据
证据之一
Rotation curves
NGC 2403 rotation curve and model.
v2 GM(r) r
Needs for an extra component which does not emit visible light Kepler law indicates that the M(r) is increasing with r First evidences found in 30’ by:
宇宙中的暗组分
最近观测宇宙学资料,宇宙中暗能 量占总能量的74%,暗物质占 22%,物质仅占4%。
1)暗能量
暗能量的发现: 2019年,两个研究Ia型超新星小组宣布发现暗能量
暗能量被认为是宇宙膨胀加速的原因。Ia型超新星就像 路灯,它们看起来比过去的“标准宇宙学”预言的要更 加远离我们:
目前存在的模型大致可以分为以下五类:G(DBຫໍສະໝຸດ 0) > G(DB<0)
• 可能的物理
– 质子衰变 – CP破坏
老的大统一解释:
大统一肯定破坏重子数守恒。 大统一能标上的粒子X衰变
B (X q ) B (X q )
新观察到的直接CP破坏过程 ε’ :
B ( K 0 ) B ( K 0 )
大统一的解释存在磁单极问题。
和谐模型(concordance model) 74%暗能量 4%重子物质 22%暗物质
4)真空的选择
真空的选择可以说是理论物理和宇宙学的终极问题,内 涵包括:
15-Is-American-Falling-Apart
Lesson FifteenIs America Falling Apart15-1 I am back in Bracciano, a castellated town about 13 miles north of Rome, after a year in New Jersey.I find the Italian Government still unstable, gasoline more expensive than anywhere in the world, butchers and bank clerks and tobacconists ready to go on strike at the drop of a hat, neo-fascists at their dirty work, the hammer and sickle painted on the rumps of public statues, a thousand-lira note (officially worth about $ shrunk to the slightness of a dollar bill.15-2 Nevertheless, it's delightful to be back.People are underpaid but they go through an act of liking their work, the open markets are luscious with esculent color , the community is important than the state, the human condition is humorously accepted.The northern wind blows viciously today, and there's no central heating to turn on, but it will be pleasant when the wind drops.The two television channels are inadequate, but next Wednesday's return of an old Western is something to look forward to.Manifold consumption isn't important here.The quality of life has nothing to do with the quantity of brand names.What matters is talk, family, cheap wine in the open air, the wresting of minimal sweetness out of the long-known bitterness of living .I was spoiled in New Jersey.美国在分崩离析吗在新泽西呆了一年后,我又回到了布拉格奇阿诺,这是位于罗马北部13英里外的一个城堡式的小镇。
法国纪录片《家园》Home中英文旁白
中英文对照字幕请听我说Listen to me, please.你跟我一样,是智人You're like me, a Homo sapiens.一个有智慧的人A wise human.生命是宇宙的奇迹Life, a miracle in the universe,出现于约四十亿年前appeared around four billion years ago,而我们人类只有二十万年历史and we humans only 200,000 years ago.但是我们却破坏了Yet we have succeeded in disrupting the balance...地球生命赖以生存的平衡that is so essential to life on Earth.请细听这个不寻常的的故事,你的故事Listen carefully to this extraordinary story, which is yours,然后决定你应该做什么and decide what you want to do with it.这是我们的起源的轨迹These are traces of our origins.最初,我们的星球不过是一个浑沌的火球At the beginning, our planet was no more than a chaos of fire,伴随它的恒星--太阳诞生而形成的formed in the wake of its star, the sun.一团粘聚的尘埃颗粒A cloud of agglutinated dust particles,就像宇宙里面许多类似的星云similar to so many similar clusters in the universe.然而生命的奇迹就在此诞生Yet this was where the miracle of life occurred.今天,我们的生命Today, life- our life-是地球上无数生物形成的生命链中的一环is just a link in a chain of innumerable living beings...在近40亿年里,这些生物被彼此继承取代that have succeeded one another on Earth over nearly four billion years.即使到了今天,新的火山继续改变我们的景观And even today, new volcanoes continue to sculpt our landscapes.它们让我们目睹了盘古初开时地球的样子They offer a glimpse of what our Earth was like at its birth熔石从深处涌出molten rock surging from the depths,开始凝固,裂开solidifying, cracking,冒着泡,或摊开形成薄的外壳blistering or spreading in a thin crust,然后再休眠一段时间before fabling dormant for a time.这些从地球内部吐出缭绕的烟圈These wreaths of smoke curling from the bowels of the Earth...是地球原始大气层的见证bear witness to the Earth's original atmosphere.一个没有氧气的大气层An atmosphere devoid of oxygen.稠密的大气层,充满水蒸气和二氧化碳A dense atmosphere, thick with water vapor,full of carbon dioxide.一个熔炉A furnace.因为有水,地球有了一个与众不同的未来But the Earth had an exceptional future, offered to it by water.地球与太阳之间的距离适中不太远,不太近At the right distance from the sun— not too far, not too near因此地球上的水能够处于液体状态the Earth was able to conserve water in liquid form.水蒸气凝结后形成滂沱大雨降落在地球上Water vapor condensed and fell in torrential downpours on Earth,河流出现了and rivers appeared.河流改变了地球表面The rivers shaped the surface of the Earth,刻削着河道cutting their channels,并冲刷出山谷furrowing out valleys.它们流向地球上最低洼的地方形成海洋They ran toward the lowest places on the globe to form the oceans.水溶解了岩石的矿物质They tore minerals from the rocks,渐渐的,海洋中的淡水and gradually the freshwater of the oceans...变成了咸水became heavy with salt.水是生命必需的液体Water is a vital liquid.它灌溉了这些广阔的不毛之地It irrigated these sterile expanses.水流就像人体的血管The paths it traced are like the veins of a body,树木的枝丫,是让大地苏醒的液体导管the branches of a tree, the vessels of the sap that it brought to the Earth.40亿年后Nearly four billion years later,地球上的某些地方还能找到这样的艺术创作somewhere on Earth can still be found these works of art,火山灰混合着来自冰岛冰川的水left by the volcanoes' ash, mixed with water from Iceland's glaciers.就是它们,物质和水There they are- matter and water,水和物质water and matter-软硬组合,这对地球上所有生物都是至关重要的soft and hard combined, the crucial alliance shared by every life-form on our planet.金属矿物元素比地球还要古老Minerals and metals are even older than the Earth.它们是星尘They are stardust.它们让地球五彩斑斓They provide the Earth's colors.红色是铁,黑色是碳Red from iron, black from carbon,蓝色是铜,黄色则是硫blue from copper, yellow from sulfur.我们来自什么哪里?Where do we come from?生命火花从哪里迸发?Where did life first spark into being?一个时光奇迹A miracle of time,地球上的温泉仍然有原始的生命存活primitive life-forms still exist in the globe's hot springs.它们赋予温泉颜色They give them their colors.它们叫做“古细菌”They're called archaeobacteria.它们都依靠地球热能生存They all feed off the Earth's heat除了蓝细菌,或是蓝绿藻以外all except the cyanobacteria, or blue-green algae.只有它们可以向着太阳来吸取其能量They alone have the capacity to turn to the sun to capture its energy.它们是古今所有植种的最重要的祖先They are a vital ancestor of all yesterday's and today's plant species.这些微小的细菌These tiny bacteria...及其数以亿计的后代and their billions of descendants...改变了地球的命运changed the destiny of our planet.是它们改造了地球的大气层They transformed its atmosphere.毒害大气层的碳去了哪里?What happened to the carbon that poisoned the atmosphere?它还存在,只是被“囚禁”在地壳It's still here, imprisoned in the Earth's crust.想要了解地球历史的这一篇章We can read this chapter of the Earth's history...卡罗拉多大峡谷的峭壁是最好的选择nowhere better than on the walls of Colorado's Grand Canyon.它们展现了地球近20亿年的历史They reveal nearby two billion years of the Earth's history.大峡谷曾经是一个聚居着微生物的海洋Once upon a time, the Grand Canyon was a sea inhabited by microorganisms.它们汲取从大气层溶解到海洋里的碳They grew their shells by tapping into carbon from the atmosphere...并长出外壳dissolved in the ocean.它们死后When they died, the shells sank...外壳沉到海床堆叠起来and accumulated on the sealed.这些地层就是它们无数的外壳构成的These strata are the product of those billions and billions of shells.因为有了它们,碳从大气层中排出Thanks to them, the carbon drained from the atmosphere,其他生物才能得以发展and other life-forms could develop.生命改变了大气层It is life that altered the atmosphere.植物靠太阳能存活Plant life fed off the sun's energy,这能量使植物分离水分子which enabled it to break apart the water molecule...并释放出来氧气and take the oxygen.空气因而充满氧气And oxygen filled the air.地球的水不断更新循环The Earth's water cycle is a process of constant renewal.瀑布,水蒸气,Waterfalls, water vapor,云、雨、泉clouds, rain, springs,河流、海洋、冰川rivers, seas, oceans, glaciers.这个循环从未间断The cycle is never broken.地球的水量恒久不变There's always the same quantity of water on Earth.历来的生物都喝同样的水All the successive species on Earth have drunk the same water.水是令人惊叹的物质The astonishing matter that is water.是最不稳定的一种One of the most unstable of all.它可以是液态的流水It takes a liquid form as running water,气态的蒸汽gaseous as vapor...或是固态的冰or solid as ice.在西伯利亚,冬季结冰的湖面In Siberia, the frozen surfaces of the lakes in winter...蕴含着水在结冰时展现的力量contain the traces of the forces that water deploys when it freezes.冰比水轻因而浮于水面Lighter than water, the ice floats,不会沉到湖底rather than sinking to the bottom.它形成御寒的保护罩It forms a protective mantle against the cold,冰下的生命可以延续under which life can go on.生命的引擎连锁结合The engine of life is linkage.一切都连结起来Everything is linked.没有东西是自给自足的Nothing is self-sufficient.水和空气不可分割Water and air are inseparable,为了地球上的生命而结合united in life and for our life on Earth.于是,形成于海洋上的云给陆地带来降雨Thus, clouds form over the oceans and bring rain to the landmasses,河流再将水带回海洋whose rivers carry water back to the oceans.分享就是一切Sharing is everything.从云层窥望的大片绿色是空气中的氧气The green expanse peeking through the clouds is the source of oxygen in the air.七成氧气来自海藻Seventy percent of this gas, without which our lungs cannot function,这些海藻给海洋表面染上了颜色comes from the algae that tint the surface of the oceans.地球要依赖Our Earth relies on a balance...万物各司其职in which every being has a role to play...互相依存的生态平衡and exists only through the existence of another being.一种敏感而脆弱的和谐,极易破碎A subtle, fragile harmony that is easily shattered.于是海藻和贝壳的结合形成了珊瑚Thus, corals are born from the marriage of algae and shells.澳大利亚沿海的大堡礁The Great Barrier Reef, Off the coast of Australia,绵延三十五万平方公里stretches over 350,000 square kilometers...哺育着一千五百种鱼类,and is home to 1,500 species of fish,四千种软体动物4,000 species of mollusks...和四百种珊瑚and 400 species of coral.每个海洋的生态平衡都依靠这些珊瑚The equilibrium of every ocean depends on these corals.地球计算时间以十亿年计The Earth counts time in billions of years.它花了四十多亿年创造了树木It took more than four billion years for it to make trees.在物种的链条中In the chain of species,树木是至高无上的trees are a pinnacle,是完美的活的雕塑a perfect living sculpture.它们蔑视地心吸力Trees defy gravity.它们是唯一永恒地朝向天空的自然元素They are the only natural element in perpetual movement toward the sky.它们的枝叶不疾不徐地向着太阳生长They grow unhurriedly toward the sun that nourishes their foliage.它们从微小的古细菌继承了They have inherited from those minuscule cyanobacteria...吸收光线能量的能力the power to capture light's energy.它们储存并利用此能量They store it and feed off it,并使其变成木材和树叶turning it into wood and leaves,然后又分解成水,矿物,植物which then decompose into a mixture of water,和生命物质的混合体mineral, vegetable and living matter.就这样And so, gradually,生命不可或缺的土壤逐渐形成the soils that are indispensable to life are formed.土壤是生物多样性的工厂Soils are the factory of biodiversity.它们是不断活动的世界They are a world of incessant activity...微生物觅食,挖掘,透气,蜕变where microorganisms feed, dig, aerate and transform.它们制造腐植土,在这肥沃的土层上所有生命互相紧扣They make the humus, the fertile layer to which all life on land is linked.地球上的生命我们知道什么?What do we know about life on Earth?我们认识多少品种?How many species are we aware of?十分之一?还是百分之一?A 10th of them? A hundredth perhaps?对于它们之间的相互关系我们知道什么?What do we know about the bonds that link them?地球是个奇迹The Earth is a miracle.生命仍是个谜Life remains a mystery.动物的家族得以形成Families of animals form,至今仍存的习惯和仪式使它们凝聚united by customs and rituals that survive today.有些适应了环境Some adapt to the nature of their pasture,有些是环境适应它们and their pasture adapts to them.双方都受益And both gain.动物得到食物,而树木能够开花结果The animal sates its hunger, and the tree can blossom again.在地球上生命的伟大的历险中In the great adventure of life on Earth,每种生物各司其职every species has a role to play,各有其位every species has its place.没有多余或有害None is futile or harmful.它们互相抵消They all balance out.然后你们And that's where you,这些聪明的人类Homo sapiens- "wise human'-进入剧情enter the story.你们得益于You benefit from a fabulous...地球四十亿年的遗产four-billion-year-old legacy bequeathed by the Earth.你们只有二十万年历史You're only 200,000 years old,但你们已经改变了世界的面貌but you have changed the face of the world.尽管你们脆弱Despite your vulnerability,但你们占据了所有的栖息地you have taken possession of every habitat...征服了所有土地and conquered swaths of territory...之前任何生物都未曾做过like no other species before you.经过十八万年的游牧岁月After180,000 nomadic years,气候变得温和,人类开始定居下来and thanks to a more clement climate, humans settled down.他们不再依靠打猎为生They no longer depended on hunting for survival.他们定居于充满渔猎They chose to live in wet environments...和野生植物的潮湿环境that abounded in fish, game and wild plants.这里土地,水和生命结合There, where land, water and life combine.人类的天赋让他们发明了独木舟Human genius inspired them to build canoes,用于开拓新的视野an invention that opened up new horizons...人类变成了航海家and turned humans into navigators.即使今天,大部分人类Even today, the majority of humankind...都居住在大陆的海岸线lives on the continents' coastlines...或是河边和湖畔or the banks of rivers and lakes.最初的城镇出现在6000多年前The first towns grew up less than 600 years ago.这是人类历史的一大步It was a considerable leap in human history.为什么呢?因为这能使人类更容易的保护自己Why towns? Because they allowed humans to defend themselves more easily.他们变成了社会人They became social beings,在一起分享他们的知识和手艺meeting and sharing knowledge and crafts,融合他们的共性和不同blending their similarities and differences.简而言之,他们文明化了In a word, they became civilized.但他们可用的能量只是双臂But the only energy at their disposal was provided by nature...和大自然赋予的东西and the strength of their bodies.这是人类数千年来的故事It was the story of humankind for thousands of years.也是现今四分之一人类It still is for one person in four-即十五亿人的故事over one and a half billion human beings-比富裕国家人口的总和还多more than the combined population of all the wealthy nations.他们只从地球获取必须的用品Taking from the Earth only the strictly necessary.很长一段时间,人类和地球的关系For a long time, the relationship between humans and the planet...平衡对等was evenly balanced.很长一段时间,经济看起来是自然公正的联盟For a long time, the economy seemed like a natural and equitable alliance.但人类寿命短暂,艰苦劳动大行其道But life expectancy is short, and hard labor takes its toll.大自然的不可预知加重日常负担The uncertainties of nature weigh on daily life.教育是罕有特权Education is a rare privilege.子女是家庭唯一资产Children are a family's only asset,每双手as long as every extra pair of hands...对家庭的生存都要作出贡献is a necessary contribution to its subsistence.地球为我们提供食物和衣物The Earth feeds people, clothes them...以及日常所需and provides for their daily needs.一切来自地球Everything comes from the Earth.城镇改变人类本质和命运Towns change humanity's nature, as well as its destiny.农夫变成了工匠、商人和小贩The farmer becomes a craftsman, trader or peddler.农夫收获,城镇居民购买,或是物物交换What the Earth gives the farmer, the city dweller buys, sells or barters.商品交易Goods change hands,伴随思想交流along with ideas.人类的天份在于经常洞悉自已的弱点Humanity's genius is to have always had a sense of its weakness.他们很想扩张领土Humans tried to extend the frontiers of their territory,但明白自身局限but they knew their limits.大自然不曾赋予他们的能量和气力The physical energy and strength with which nature had not endowed them...他们在动物身上找到,并驯养它们为己服务was found in the animals they domesticated to serve them.空着肚子怎去征服世界?But how can you conquer the world on an empty stomach?农业的发明The invention of agriculture...彻底改变了到处觅食的野兽本质transformed the future of the wild animals scavenging for food...成为真正的人that were humankind.农业改写了人类历史Agriculture turned their history on end.农业是人类的第一场伟大革命Agriculture was their first great revolution.八千至一万年前开始Developed barely 8,000 to 10,000 years ago,农业改变了人类与自然的关系it changed their relationship to nature.它终结了人类不稳定的狩猎和采集时代It brought an end to the uncertainty of hunting and gathering.第一次有了盈余It resulted in the first surpluses...这催生了城市和文明and gave birth to cities and civilizations.为了农业生产For their agriculture,人类利用动物或植物的能量humans harnessed the energy of animal species and plant life,并从中受益from which they at last extracted the profits.数千年艰苦觅食的记忆逐渐淡忘The memory of thousands of years scrabbling for food faded.他们学会将谷类适应They learned to adapt the grains that are the yeast of life...不同的土壤和气候to different soils and climates.他们学会增加农作物的收成和种类They learned to increase the yield and multiply the number of varieties.像地球上所有动物Like every species on Earth,人类每天的首要任务the principal daily concern of all humans...是喂饱自已和家人is to feed themselves and their family.当土瘠水稀的时候When the soil is less generous and water becomes scarce,人类要为一点干燥土地humans deploy prodigious efforts to mark a few arid acres...而拼命劳作with the imprint of their labor.人类以极大的耐性和专注去模塑土地Humans shaped the land with the patience and devotion that the Earth demands,近乎祭神仪式般不停地重复in an almost sacrificial ritual performed over and over.农业仍然是世界上最普遍的职业Agriculture is still the world's most widespread occupation.一半人类仍在耕种土地Half of humankind tills the soil,超过四分之三仍是手工操作over three-quarters of them by hand.农业像传统般一代接一代Agriculture is like a tradition handed down...有血有汗地薪火相传from generation to generation in sweat, graft and toil,因为它是人类生存的先决条件because for humanity it is a prerequisite of survival.人类依赖人力日久But after relying on muscle power for so long,开始发掘地球深处的能量humankind found a way to tap into the energy buried deep in the Earth.这些火焰也来自植物These flames are also from plants.一束阳光A pocket of sunlight.纯粹的能量,太阳量Pure energy— the energy of the sun于一亿年前被数以百万计的树木captured over millions of years by millions of plants...俘虏了超过数百万年more than a hundred million years ago.那是煤,是天然气It's coal. It's gas.最重要的是石油And above all, it's oil.这束阳光把人类从辛劳的耕种解放出来And this pocket of sunlight freed humans from their toil on the land.石油令人类解除了时间的束缚With oil began the era of humans who break free of the shackles of time.石油令一部分人得享从未有过的舒适With oil, some of us acquired unprecedented comforts.五十年里,仅仅一代人的时间And in 50 years, in a single lifetime,地球发生根本性的改变the Earth has been more radically changed...是前人从未做过的than by all previous generations of humanity.越来越快Faster and faster.过去六十年,人类人口倍增In the last 60 years, the Earth's population has almost tripled,超过二十亿人移居城市and over two billion people have moved to the cities.越来越快Faster and faster.深圳四十年前只是偏僻渔村Shenzhen, in China, with its hundreds of skyscrapers and millions of inhabitants,现在拥有数以百计的摩天大楼和数百万人口was just a small fishing village barely 40 years ago.越来越快Faster and faster.二十年来In Shanghai, 3,000 towers and skyscrapers...上海建了三千座高楼大厦have been built in 20 years.另有数百座正在建设中Hundreds more are under construction.今天,地球上七十亿人口有一半住在城市Today, over half of the world's seven billion inhabitants live in cities.纽约,世界上第一个超级城市New York. The world's first megalopolis...是人类无止境地is the symbol of the exploitation of the energy...剥削地球资源的像征the Earth supplies to human genius.数百万移民的人力资源The manpower of millions of immigrants,煤的能量the energy of coal,及无约束的石油力量the unbridled power of oil.电的出现发明了电梯Electricity resulted in the invention of elevators,而电梯使得摩天大厦成为可能which in turn permitted the invention of skyscrapers.纽约在全球经济排名中位列16New York ranks as the 16th-largest economy in the world.美国最先发现和开发利用America was the first to discover, exploit and harness...珍贵而具革命性的能量“黑金”the phenomenal revolutionary power of black gold.借助它With its help,农夫变成了农业企业家a country of farmers became a country of agricultural industrialists.机器取代人力Machines replaced men.一升石油等于A liter of oil generates as much energy...一百双手在24小时产生的能量as 100 pairs of hands in 24 hours,但在全球只有3%的农民使用拖拉机but worldwide only three percent of farmers have use of a tractor.尽管如此,他们的粮食产出还是支配着地球Nonetheless, their output dominates the planet.美国只剩下三百万农民In the United States, only three million farmers are left.他们出产的谷物可以养活二十亿人口They produce enough grain to feed two billion people.但大部分谷物并非用作食粮But most of that grain is not used to feed people.就像其他工业国Here, and in all other industrialized nations,谷物用来喂牲口或作生化燃料it's transformed into livestock feed or biofuels.这束阳光的能量The pocket of sunshine's energy...赶走了令土地干旱的幽灵chased away the specter of drought that stalked farmland.所有泉水都用于农业No spring escapes the demands of agriculture,它占人类水消耗量的70%which accounts for 70% of humanity's water consumption.大自然的一切都互相连系In nature, everything is linked.耕地的拓张和单一品种的种植The expansion of cultivated land and single-crop farming...增加了害虫的肆虐encouraged the development of parasites.石油化工革命带来的杀虫剂Pesticides, another gift of the petrochemical revolution,把它们杀光exterminated them.农作欠收和饥荒成为邀远回忆Bad harvests and famine became a distant memory.眼前最头痛是The biggest headache now...如何处理现代农业带来的残留was what to do with the surpluses engendered by modern agriculture.有毒的杀虫剂渗进空气But toxic pesticides seeped into the air,泥土、动植物、河流和海洋soil, plants, animals, rivers and oceans.它们入侵一切生命They penetrated the heart of cells...赖以生存的细胞核心similar to the mother cell that is shared by all forms of life.它们对免于饥饿的人类有害吗?Are they harmful to the humans that they released from hunger?这些穿着黄色保护衣物的农夫These farmers, in their yellow protective suits,可能有更好的主意probably have a good idea.新兴农业免除了对土壤和季节的依赖The new agriculture abolished the dependence on soils and seasons.肥料令小片土地Fertilizers produced unprecedented results...出产前所未见的丰富收成on plots of land thus far ignored.适应了土地和气候的谷物Crops adapted to soils and climates...被产量高和易于运输的品种所取代gave way to the most productive varieties and the easiest to transport.于是在上一世纪And so, in the last century,农民在过去数千年培育的three-quarters of the varieties developed by farmers over thousands of years...四分之三的品种绝种have been wiped out.极目所见,下施肥料,上覆塑料As far as the eye can see, fertilizer below, plastic on top.西班牙的艾美利亚温室The greenhouses of Almeria in Spain...是欧洲的菜园are Europe's vegetable garden.大批形状整齐的蔬菜A city of uniformly sized vegetables...每天等候数以百计的卡车waits every day for the hundreds of trucks...把它们运送到欧洲大陆的超级市场that will take them to the continent's supermarkets.国家越发展The more a country develops,国民对肉类的需求就越大the more meat its inhabitants consume.不依靠集中饲养式牛场How can growing worldwide demand be satisfied...如何满足全球日益增长的需求without recourse to concentration camp-style cattle farms?越来越快Faster and faster.就像家畜一生都不会见到牧场Like the life cycle of livestock which may never see a meadow,比动物生长更快的肉类生产成为日常程序manufacturing meat faster than the animal has become a daily routine.被数百万牛践踏的辽阔饲场In these vast food lots, trampled by millions of cattle,寸草不生not a blade of grass grows.一队队卡车从全国各地运来A fleet of trucks from every corner of the country...数以吨计的谷物,黄豆和brings in tons of grain, soy meal...丰富蛋白质的饲料最终变成一吨吨的肉and protein-rich granules that will become tons of meat.结果是生产一公斤马铃薯The result is that it takes 100 liters of water...要一百公升水to produce one kilogram of potatoes,一公斤米要四千公升水4,000 for one kilo of rice...而一公斤牛肉要一万三千公升水and 13,000 for one kilo of beef.还不算在生产和运输过程被耗掉的石油Not to mention the oil guzzled in the production process and transport.我们的农业成了石油推动型Our agriculture has become oil-powered.它能养活地球上双倍的人口It feeds twice as many humans on Earth...但多元性被标准化取代but has replaced diversity with standardization.它让我们享受到梦中才有的舒适It has offered many of us comforts we could only dream of,但却使我们的生活方式完全依赖石油but it makes our way of life totally dependent on oil.这是新的时间观念This is the new measure of time.我们的时钟随着那Our world's clock now beats to the rhythm...永不言倦的阳光机器的节奏of these indefatigable machines...一起摆动tapping into the pocket of sunlight.它们的规律性让我们安心Their regularity reassures us.极小的间断都会引发混乱The tiniest hiccup throws us into disarray.整个地球都注意到了我们The whole planet is attentive to these metronomes...寄托希望和幻想的节拍器of our hopes and illusions.同样的希望和幻想随着我们的需求The same hopes and illusions that proliferate along with our needs,以及越来越难以满足的欲望和浪费而增加increasingly insatiable desires and profligacy.我们知道廉价石油时代即将终结We know that the end of cheap oil is imminent,但我们拒绝相信but we refuse to believe it.对大多数人来说,美国梦体现在一个传奇的名字上:For many of us, the American dream is embodied by a legendary name:洛杉矶Los Angeles.在这个方圆一百公里的城市In this city that stretches over100 kilometers,汽车的数量几乎与人口相等the number of cars is almost equal to the number of inhabitants.这里,晚上是能源卖力表演的时该Here, energy puts on a fantastic show every night.白天不过是夜晚的苍白反映The days seem to be no more than the pale reflection of nights...晚上的城市变成闪烁星空that turn the city into a starry sky.越来越快Faster and faster.距离不再以英哩度量而是多少分钟车程Distances are no longer counted in miles but in minutes.汽车重塑郊区面貌,每个房子都好像城堡般The automobile shapes new suburbs where every home is a castle,跟令人窒息的市中心保持安全距离a safe distance from the asphyxiated city centers,一排排整齐的房子拥挤在死胡同四周and where neat rows of houses huddle round dead-end streets.少数发达国家的模式The model of a lucky few countries...通过遍及全球的电视节目has become a universal dream,已变成了普遍梦想preached by televisions all over the world.即使在北京Even here in Beijing,这些模仿,抄袭和复制it is cloned, copied and reproduced...千篇一律的房子已把古塔从地图上抹去了in these formatted houses that have wiped pagodas off the map.汽车成为舒适和进步的象征The automobile has become the symbol of comfort and progress.如果每个社会都跟随这个模式If this model were followed by every society,今天地球不会只有九亿辆汽车the planet wouldn't have 900 million vehicles, as it does today,而是五十亿but five billion.越来越快Faster and faster.世界越发展,对能源的渴求就更高The more the world develops, the greater its thirst for energy.到处都是挖钻矿物的机器Everywhere, machines dig, bore and rip from the Earth...把盘古初开时埋在地下的星星挖出来the pieces of stars buried in its depths since its creation:矿物minerals.未来二十年人类从地球开采的矿物In the next 20 years, more ore will be extracted from the Earth...比人类历史上的总数都要多than in the whole of humanity's history.由于垄断As a privilege of power,80%开采所得财富80% of this mineral wealth...只由20%的人口分享is consumed by 20% of the world's population.到本世纪末Before the end of this century,由于过份开采矿产,人类将会耗尽地球上的大部分资源excessive mining will have exhausted nearly all the planet's reserves.越来越快Faster and faster.造船厂大量制造油轮Shipyards churn out oil tankers,货柜船,煤气运输船container ships and gas tankers...以应付世界性工业生产的需求to cater for the demands of globalized industrial production.大部分消费品要千里迢迢地Most consumer goods travel thousands of kilometers...从产地运到消费地from the country of production to the country of consumption.自1950年至今,国际贸易总量Since 1950, the volume of international trade...增长了二十倍has increased 20 times over.90%的贸易在海上进行Ninety percent of trade goes by sea.每年多达五亿的货柜500 million containers are transported every year,被运往主要的消费地区headed for the world's major hubs of consumption,例如迪拜such as Dubai.迪拜是世界上最大的建筑工地之一Dubai is one of the biggest construction sites in the world一个将不可能变成可能的国家a country where the impossible becomes possible.例如在大海中建造人工岛Building artificial islands in the sea, for example.迪拜缺乏自然资源Dubai has few natural resources,但依靠石油赚的钱,它可以输入数百万吨的原料but with the money from oil, it can bring millions of tons of material and people...和来自世界各地的人口from all over the world.它可以建造大厦丛林,一个比一个高It can build forests of skyscrapers, each one taller than the last,甚至在沙漠中建滑雪道or even a ski slope in the middle of the desert.迪拜没有农田,但可以进口食物Dubai has no farmland, but it can import food.迪拜没有水源。
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a rXiv:h ep-ph/2710v328May23Need the masses of unstable particles and their antiparticles be equal in the CPT–invariant system?K.Urbanowski ∗University of Zielona Gora,Institute of Physics,ul.Podgorna 50,65-246Zielona Gora,Poland.February 7,2008PACS numbers:03.65.Ca.,11.30.Er.,11.10.St.,14.40.Aq.Keywords:CPT invariance;Unstable particles;Particle–antiparticle masses;Matter–antimatter asymmetry.Abstract We show that the real parts of diagonal matrix elements of the exact effective Hamiltonian governing the time evolution in the sub-space of states of neutral kaons and similar particles can not be equal for t >t 0(t 0is the instant of creation of the pair K 0,K 0,need not be equal for t ≫t 0in the caseof preserved CPT and violated CP symmetries.1IntroductionAll known CP–and hypothetically possible CPT–violation effects in the neu-tral kaon complex are described by solving the Schr¨o dinger–like evolutionequation[1]—[11](we use¯h=c=1units)∂iK0>,and so on,(then states corresponding with the decay products belong to H⊖H def=H⊥),and nonhermitian effective Hamiltonian H obtained usually by means of the Lee–Oehme–Yang(LOY) approach(within the Weisskopf–Wigner approximation(WW))[1]—[11]:iH ≡M−U(t)|ψ>||=HU(t)|ψ>||,U(t=t0)=I,(3)∂twhere I is the unit operator in H,H is be total(selfadjoint)Hamilto-nian acting in H and U(t)the total unitary evolution operator,|ψ>||≡|ψ,t=t0>||∈H||is the initial state of the system.Solutions of Eq.(1)can be written in matrix form and such a matrix defines the evolution operator(which is usually nonunitary)U (t)acting in H :|ψ;t> def=U (t)|ψ> ,(4) where,|ψ> ≡q1|1>+q2|2>,(5) and|1>stands for the vectors of the|K0>,|B0>type and|2>denotes antiparticles of the particle”1”:|B0>,<j|k>=δjk,j,k=1,2.Relations between matrix elements of H implied by the CPT–transfor-mation properties of the Hamiltonian H of the total system,containing the neutral kaon complex as a subsystem,are crucial for designing CPT–invariance and CP–violation tests and for proper interpretation of their re-sults.The standard interpretation of matrix elements,h jk=<j|H|||k>, (j.k=1,2),of the effective Hamiltonian H||follows form the properties of2the LOY effective Hamiltonian H||≡H LOY.In many papers it is assumed that the real parts,ℜ(.),of the diagonal matrix elements of H :ℜ(h jj)≡M jj,(j=1,2),(6) whereh jk=<j|H |k>,(j,k=1,2),(7) correspond to the masses of particle”1”and its antiparticle”2”respectively [1]—[11],(and such an interpretation ofℜ(h11)andℜ(h22)will be used in this paper),whereas the imaginary parts,ℑ(.),are interpreted as the decay widths of these particles,Γjj≡−2ℑ(h jj),(j=1,2),[1]—[11],[15].Taking H||=H LOY and assuming that the CPT invariance holds in the system considered one easilyfinds the standard result of the LOY approachh LOY 11=h LOY22,(8)which,among others,means thatM LOY11=M LOY22,(9)where M LOYjj =ℜ(h LOYjj)and h LOYjj=<j|H LOY|j>,(j=1,2).This lastrelation is interpreted as the equality of masses of the unstable particle|1> and its antiparticle|2>.In[16]using the Khalfin’s Theorem[9,17]—[19]it was proved that, contrary to the conclusion drawn in(8),the diagonal matrix elements of the exact effective Hamiltonian H||in a CPT invariant but CP noninvariant system must be different for t>t0.This proof is rigorous.A crucial conclu-sion following from this property was put forward in[16].This conclusion states that,contrary to property(9),the masses of unstable particle and its antiparticle should be different for t>t0.In fact,this conclusion was not supported there by a direct and rigorous proof.The aim of this note is to complete the result of[16]and to prove this conclusion.Strictly speaking,to prove rigorously that in the case of the exact H||it must beℜ(h11−h22)=0 for t>t0,if the CPT symmetry holds and CP is violated.In order to realize this purpose,the method applied in[14]will be used.32CPT transformation propertiesof the exact HThe aim of this Section is to show that in the case of the exact H||,the stan-dard LOY relation(9)does not occur if the total system under consideration is CPT invariant,ΘHΘ−1=H+≡H,that is[Θ,H]=0,(10) whereΘis the antiunitary operator:Θdef=CPT,(11) and CP noninvariant.Let P denote the projection operator onto the subspace H :P H=H ,P=P2=P+,(12) then the subspace of decay products H⊥equalsH⊥=(I−P)H def=Q H,Q≡I−P.(13) For the case of neutral kaons or neutral B–mesons,etc.,the projector P can be chosen as follows:P≡|1><1|+|2><2|.(14) We assume that time independent basis vectors|K0>and|>Kcan be identified with the eigenvectors of the so–called free Hamiltonian H(0)≡H strong=H−H(1),where H(1)≡H int denotes weak and other in-teractions which are responsible for transitions between eigenvectors of H(0), i.e.,for the decay process.This means that[P,H(0)]=0.(15) The condition guaranteeing the occurrence of transitions between subspaces H and H⊥,i.e.,a decay process of states in H ,can be written as follows[P,H]=0,(16)4Note that Eq.(3)means that U(t)=exp(−itH).Now,knowing U(t), the exact evolution operator U (t)(4)for H can be expressed using the projector P as followsU (t)≡P U(t)P.(17) We have U (0)≡P.In[12,13,14]an observation was made that for every effective Hamiltonian H governing the time evolution in subspace H ≡P H, the following identity holds:∂U (t)H ≡H (t)≡iH .This means that for the projector P defining this subspace the following relation must hold,[Θ,P]=0.(25) Using assumption(25)and the identity(20),after some algebra,onefinds [24](see Appendix A)[Θ,H (t)]=A(t)+B(t),(26)where:A(t)=P[Θ,H]U(t)P(U (t))−1,(27)B(t)= P H−P HU(t)P(U (t))−1P [Θ,U(t)]P(U (t))−1(28)≡ P H−H (t)P [Θ,U(t)]P(U (t))−1(29)≡ P HQ−V (t)P [Θ,U(t)]P(U (t))−1(30) We observe that for t=0A(0)≡P[Θ,H]P and B(0)≡0.(31)From definitions and the general properties of operators C,P and T[4,8, 25,26,27]it is known that T U(t=0)=U+(t=0)T=U(t=0)T(Wigner’s definition for T is used),and therebyΘU(t=0)=U+(t=0)Θ[25,26,27] i.e.[Θ,U(t=0)]=0.So,the component B(t)in(26)is nonzero for t=0 and it is obvious that there is a chance for theΘ–operator to commute with the effective Hamiltonian H (t=0)only if[Θ,H]=0.On the other hand, the property[Θ,H]=0does not imply that[Θ,H (0)]=0or[Θ,H (0)]=0. These two possibilities are admissible,but if[Θ,H]=0then there is only one possibility:[Θ,H (0)]=0[14].From(26)wefindΘH (t)Θ−1−H (t)≡(A(t)+B(t))Θ−1.(32)Now,keeping in mind that|2>≡|Adding expression(33)to its complex conjugate one getsℜ(h11(t)−h22(t))=ℜ<2|(A(t)+B(t))Θ−1|2>.(34)Note that if the requirement(16)for the projector P(14)is replaced by the following one:[P,H]=0,(35) i.e.if only stationary states are considered instead of unstable states,then one immediately obtains from(27)—(30):A(t)=P[Θ,H]P,(36)B(t)=0.(37)Let us assume that conditions(16)and(10)hold.For the station-ary states(35),the assumption(10),relations(36),(37)and(34)yield ℜ(h11(t)−h22(t))=0.Now let us consider the case of unstable states,i.e.,states|1>,|2>, which lead to such projection operator P(14)that condition(16)holds.If in this case(10)also holds then A(t=0)≡0(see(31))and thus[Θ,H (0)] =0,which is in agreement with earlier,similar results[14,16].This means that at t=0:ℜ(h11(0)−h22(0))=H11−H22=0,(38) whereH jk=<j|H|k>,(j,k=1,2).(39) Let t>0.In this case we haveΘU(t)=U+(t)Θ,which givesΘU (t)=U+ (t)Θ,ΘU−1(t)=(U+(t))−1Θ,and[Θ,U(t)]=−2i(ℑU(t))Θ(40)This relation leads to the following result in the case of conserved CPT–symmetryB(t)=−2iP H−H (t)P (ℑU(t))P(U+ (t))−1Θ(41)≡−2i P HQ−V (t)P (ℑU(t))P(U+ (t))−1Θ,(42) which means that generally,in any case B(t>0)=0.Formulae(41),(42)allow us to conclude that<2|B(0)Θ−1|2>=0and ℜ<2|B(t>0)Θ−1|2>=0,if condition(10)holds.This means that in this7case it must beℜ(h11(t))=ℜ(h22(t))for t>0.So,there is no possibility forℜ(h11)to equalℜ(h22)for t>0in the considered case of P fulfilling the condition(16)(i.e.,for unstable states)when CPT–symmetry is conserved.Using identity(20)and assuming that[CP,H]=0and(10)hold it is not difficult to show that in such case h11(t)=h22(t).3Discussion.All the above considerations lead to the following conclusions for the matrix elements h jk of the exact effective Hamiltonian H governing the time evo-lution in neutral kaons subspace:Conclusion1If[Θ,H]=0and[CP,H]=0then it follows that M11≡ℜ(h11(t>0)) =ℜ(h22(t>0))≡M22,that is that the mass of the unstable particle”1”must be different from the mass of its antiparticle”2”for t>t0=0.One should remember that the above conclusion derived from relation (34)concerns only the real parts of h11(t>0)and h22(t>0)and it is in excellent agreement with the results presented in[16].Relations(32)—(34) give us no information about the imaginary parts of h11and h22.One cannot infer from(34)that[Θ,H]=0followsℑ(h11)=ℑ(h22).The case when [Θ,H]=0followsℜ(h11(t>0))=ℜ(h22(t>0))andℑ(h11)=ℑ(h22),is not in conflict with relations(32)—(34).The equality ofℑ(h11)andℑ(h22) need not imply the equality ofℜ(h11)andℜ(h22)and vice versa.This means that the Bell–Steinberger relations[28]do not contradict relations(32)—(34)and Conclusion1following from ly,Bell and Steinberger formulae lead to the equality ofℑ(h11)andℑ(h22)in the case of conserved CPT–symmetry and do not concern the real parts of the diagonal matrix elements of H or give any relations between them.The real parts of the diagonal matrix elements of the mass matrix H , h11and h22,are considered in the literature as masses of unstable particles |1>,|2>(e.g.,mesons K0and(j=1,2).So their interpretation as the masses of the particle”1”and its antiparticle”2”at the instant t=0seems to be explained.Note that from the identity(18)it follows that the exact effective Hamiltonian H||(t) is a continuous function of time t.Therefore the dimension of H||(t)as the physical quantity at any t>0continues to be the same as that at t=0.From(22)onefindsh jk(t)=H jk+v jk(t),(j,k=1,2),(43) where v jk(t)=<j|V||(t)|k>.So,at t>t0=0the initial mass(energy)of the particle j,ℜ(h jj(0))=<j|H|j>≡H jj,in the state|j>,shifts and takes the valueℜ(h jj(t))=H jj+ℜ(v jj(t)).(44) Every experiment performed at this instant t will indicate the quantity(44)as the energy(i.e.,as the mass)of the particle j at time t.In the case of neutral particles there are no methods allowing one to differentiate the contribution ofℜ(h jj(0))=H jj intoℜ(h jj(t))from the contribution of the shiftℜ(v jj(t)) by means of the measurement performed at the instant t>0.The particle j always interacts with the environment at the instant t as the particle with the energyℜ(h jj(t)).So from the point of view of the relativistic quantum theory the interpretation ofℜ(h jj(t))as the mass of the particle j seems to be acceptable.There is another one reason for the adoption of LOY interpretation of the matrix elements of H||in this letter.Note that,as it was mentioned in Sec.2, the LOY effective Hamiltonian,H LOY fulfils the identity(18).It seems that the interpretation of matrix elements of any effective Hamiltonian fulfilling this identity can not differ from the interpretation of matrix elements of H LOY.So Conclusion1means that masses of a decaying particle”1”and its antiparticle”2”should be different if the CPT–symmetry is conserved in the system containing these unstable particles.In other words,in the exact theory unstable states|1>,|2>appear to be nondegenerate in mass for t>t0if the CPT–symmetry holds and the CP–symmetry does not,in the total system considered.At the same time,relations(35)—(37)and(10) suggest that in the CPT–invariant system masses of a given particle and its aniparticle are equal(i.e.,appear to be degenerate)only in the case of stationary(stable)states|1>,|2>.The case,when vectors|1>,|2> describe pairs of particles p,such states.All these conclusions contradict the standard result of the LOY and related approaches.Results of the previous Section and Conclusions1are not in conflict with such implications of the CPT–invariance as the equality of particle and antiparticle decay rates—see[16].On the other hand the consequences(8) and(9)of the LOY theory are in conflict with the results of Sec.2and Conclusion1obtained without approximations but they are in agreement with the rigorous result obtained in[16].Note that in fact the above conclusions about the masses of unstable par-ticles under consideration are not in conflict with the rigorous and consistent treatment of quantum theory.From(10)(or from the CPT Theorem[29])it only follows that the masses of particle and antiparticle eigenstates of H(i.e., masses of stationary states for H)should be the same in the CPT invariant system—see[16].Such a conclusion can not be derived from(10)for particle |1>and its antiparticle|2>if they are unstable,i.e.,if states|1>,|2>are not eigenstates of H.Note also that the proof of the CPT Theorem makes use of the properties of asymptotic states[29].Such states do not exist for unstable particles.What is more,one should remember that the CPT The-orem of axiomatic quantumfield theory has been proved for quantumfields corresponding to stable quantum objects and only suchfields are considered in the axiomatic quantumfield theory.There is no axiomatic quantumfield theory of unstable quantum particles.So,all implications of the CPT The-orem(including those obtained within the S–matrix method)need not be valid for decaying particles prepared at some initial instant t0=0and then evolving in time t≥0.Simply,the consequences of CPT invariance need not be the same for systems in which time t varies from t=−∞to t=+∞and for systems in which t can vary only from t=t0>−∞to t=+∞.Similar doubts about the fundamental nature of the CPT Theorem were formulated in[30],where the applicability of this theorem for QCD was considered.One should also remember that conclusions about the equality of masses of stable particles and their antiparticles following from the properties of the S-matrix can not be extrapolated to the case of unstable states.Simply,there is no S–matrix for unstable states.The important consequence of Conclusion1is that the conventional in-terpretation of the tests,which are sensitive to the differenceℜ(h11−h22),as the CPT invariance test in neutral kaon complex,need not be longer valid. An example of a such test is considered in[31].Another consequence of the main result of the Section2,that is of the10Conclusion1concerns properties of the scalar product of eigenvectors|l>, |s>of H||,H|||l(s)>=µl(s)|l(s)>.(45)for the eigenvaluesµl(s)=12[(h11−h22)2+4h12h21]1/2≡m l(s)−iK0.Using the eigenvectors|K1(2)>def=2−1/2(|1>+(−)|2>),(46) of the CP–transformation for the eigenvalues±1(we define CP|1>=−|2>, CP|2>=−|1>),vectors|l>and|s>can be expressed as follows|l(s)>≡(1+|εl(s)|2)−1/2[|K2(1)>+εl(s)|K1(2)>].(47) This last relation leads to the following formula for the product<s|l>,<s|l>≡N(ε∗s+ε∗l),(48) where N=N∗=[(1+|εs|2)(1+|εl|2)]−1/2.By means of the following parametersεdef=12(εs−εl),(50) which are usually are used to describe the scale of CP–and possible CPT–violation effects[3,4,6,10,15],product(48)can be expressed as follows<s|l>≡2N(ℜε−iℑδ).(51) There isδ≃h11−h22γs−γl,andδ||=14(γs−γl)2,(53)δ⊥=14(γs−γl)2,(54) 11are the real parameters.Thusℑδ=δ||sin φSW +δ⊥cos φSW .(55)The consequence of (8),(9)is that in CPT invariant but CP noninvariant system δ||=δLOY ||=0and δ⊥=δLOY ⊥=0which leads to the standardresult ℑδLOY =0(here δLOY denotes the parameter δ,(52),calculated for H ||=H LOY ).From this property and (51)the conclusion that the product <s |l >must be real is drawn in the literature.This conclusion is considered as the standard result.Note that in the light of the main result of Sec.2and Conclusion 1such a conclusion seems to be wrong in the case of the exact effective Hamiltonian H ||,that is,in the case of the exact theory.From Conclusion 1one infers that there must be δ⊥=0,(54)in the case of CPT invariant but CP noninvariant system and therefore it must be ℑδ=0(see(55)in such a system.This means that the right hand side of the relation(51)is a complex number and therefore in the case of conserved CPT–and violated CP–symetries,in contrast with the standard result,there must be <s |l >=<s |l >∗in the real systems.Properties of the real systems discussed above and described in Conclu-sion 1are unobservable for the LOY approximation.In order to obtain at least an estimation of the effects described in these Conclusions,the matrix elements of H should be calculated much more exactly than it is possible within the LOY theory.A proposal of a more exact approximation is given in [21,22,32,33].This approximation is based on the Krolikowski–Rzewuski equation for a distinguished component of the state vector [34].All CP –and CPT –transformation properties of the effective Hamiltonian H calculated within this approximation are consistent with similar properties of the exact effective Hamiltonian and with the result obtained in this paper and [16].Within the mentioned more accurate approximation one finds for diagonalmatrix elements of H ≃H (1)||def =lim t →∞H (1)||(t )that the CPT–invariantsystem in contradistinction to the property (8)obtained within the LOY theory [20,21,22,33]h 11=h 22,(56)andh 11(t =0)=H 11≡H 22=h 22(t =0).(57)The relation (57)is consistent with the properties (23)and (38)and the result obtained in [16].12Assuming that|H12|≪|H0|,(58) where H0def=1∂xx=H0−H21∂Σ12(x)QHQ−ǫ−i0QHP.(60) andΣjk(ǫ)=<j|Σ(ǫ)|k>.From the result(59)it follows that∆h=0can be achieved only if H12= H21=0.Relation(15)implies that H12≡<1|H int|2>.If|1>≡|K0> and|2>≡|K0complex then predictions following from the use of the mentioned more accurate approximation and from the LOY theory should lead to the the same masses for K0and forK0mesons are ever detected in some tests,then the most plausible interpretation of this result will be the existence of interactions allowing thefirst order|∆S|=2transitions in the system considered[31].Within the use of the toy Fridrichs–Lee model[9,21]the following esti-mation was found in[16]:ℜ(∆h)This and the estimation|m K0−m<10−18(where mα,(α=K0,m K−averageK0–meson respectivelly),which can be found in[15],show that possible deviations from the standard picture,that is,from the LOY predictions are much too small to be observed with the present experiments.Confronting relations(8)with(34),one should remember that,in fact, H LOY can be considered as the lowest,nontrivial order approximation in the perturbation H(1):All the terms to higher orders than(H(1))2are neglected in H LOY[1]—[11].It is obvious that CPT–and other transformation properties of such an approximate effective Hamiltonian and of the exact one need not be the same.Taking into account all the above,it seems that for the proper understanding of the CPT–invariance tests and CPT–invariance, or possible CPT–violation phenomena it is necessary to consider higher order contributions into the LOY–type effective Hamiltonian than those contained in H LOY or to use a more accurate approximation than LOY.The result(8)of the LOY approximation is model independent whereas, within the mentioned more accurate approximation,the magnitude of ℜ(h11−h22)depends on the model of interactions considered.So a new possibility of the verification of models of weak interactions arises.It also seems,that above results have some meaning when attempts to describe possible deviations from conventional quantum mechanics are made and when possible experimental tests of such a phenomenon and CPT–invariance in the neutral kaons system are considered[35,36].In such a case a very important role is played by nonzero contributions to(h11−h22) [35,36]:The correct description of these deviations and experiments men-tioned is impossible without taking into account the results of this Section and the above Sec.2.This can not be performed within the LOY approach and requires more exact approximations.It seems that the approximation described and exploited in[20]—[22]may be a more effective tool for this purpose.The above considerations suggest that tests consisting of a comparison of the equality of the decay laws of K0and(such as LOY theory[1]—[4]based on the WW approximation),can not lay claim to being the exact and correct description of all aspects of the effects connected with the violation or nonviolation of the CP–and especially CPT–symmetries.(It occurs probably because of the fact that such theories cannot exactly satisfy unitarity[19]and lead to inconsistencies of CPT–symmetry properties of the H and the total Hamiltonians H[33]).Also, it seems that results of the experiments with neutral kaons,etc.,designed and carried out on the basis of expectations of theories within the WW approximation,such as tests of CPT invariance(at least the results of those in which CPT–invariance or CPT–noninvariance of H generated by such invariance properties of H were essential),should be revised using other methods than the WW approach.The most important observation which follows from the results of Sec. 2(Conclusion1)and of[16]is the following one:In CPT invariant system Quantum Theory allows simultaneously created at the instant t0=0unstable particles and their antiparticles as particles with the same masses to have slightly different masses for t>t0.Thus some matter–antimatter asymmetry can arise in such system,which can have cosmological consequences[37].A AppendixThe aim of this Appendix is to calculate the commutator[Θ,H (t)]discussed in Sec.2and to study some of its applications.In order to calculate this commutator it is convenient to express H (t)by means of the formula(20), and then to use assumption(25),the definition of[U (t)]−1(19)and the following propertyP[U (t)]−1=[U (t)]−1P≡P[U (t)]−1P,(A.1) which is the consequence of(19).This last observation together with the property(17)means that the identity(18)can be replaced by the following one:∂U (t)H ≡H (t)≡i=ΘP [U (t )]−1−P [U (t )]−1P Θ=P U −1 U Θ−ΘU U −1 (A.3)=−P U −1 [Θ,U ]U −1≡−P U −1 P [Θ,U ]P U −1 .(A.4)Properties (A.1)and expression (20)lead to the following formulae [Θ,H (t )]=[Θ,P HUP U −1 P ]=[Θ,P H ]UP U −1 +P H [Θ,UP U −1 ]=P [Θ,H ]UP U −1(A.5)+P H [Θ,UP ]U −1 +UP [Θ,P U −1 ] .All steps in the above formulae and in formulae leading to (A.2)have been performed without changing the order of operators appearing in products of type ΘH,ΘU (t ),etc..By virtue of the assumption (25)only the order of operators Θand P in products ΘP ,etc.,can be changed when it is necessary.Now,defining A (t )def =P [Θ,H ]UP U −1 ,(A.6)(which equals (27))and taking into account (A.3),one can obtain formula(26)from (A.4)[Θ,H (t )]≡A (t )+P H [Θ,U ]P U −1+P HUP −U −1 P [Θ,U ]P U −1=A (t )+B (t ),where (see (28))B (t )= P H −P HUP U −1 P [Θ,U ]P U −1 ,or (by means of (20))B (t )≡ P H −H P[Θ,U ]P U −1 ,(i.e.,simply (29)),and due to the properties (21),(22)B (t )= P HQ −V P[Θ,U ]P U −1 ,16that is formula(30).Let us now consider some details of the derivation of the relation(33). 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