Thermal gravitational waves
新标准大学英语视听说教程听力原文
Unit 6-Conversation 1Janet: What are you reading, KateKate:Alice in Wonderland, by Lewis Carroll. Do you know itJanet: I've heard of it, yes, but I've never read it. It's a 19th century children's story, isn't it K a te: That's right. It's very famous. It's set in Oxford. It starts with this young girl sitting on a river bank. The interesting thing is, the author, Lewis Carroll, he was an Oxford professor and he used to have tea with the girl's family on this river bank. Ja net: Oh, that's fascinating! I'll put it into my diary.Kate: Is that what you're writing I know you've been keeping a diary all the year.Janet: It's been a great year. I've had such a good time — so lucky to have Mark and Kate as friends. Feel I've been doing well with work. Much happier about asking questions in tutorials.Janet: My screen's gone dark.Mark: You're using the battery, remember. It's run out, obviously.Janet: It can't be the battery. It's still charged. Oh no it's still black. Oh dear, I hope it's nothing serious. I haven't backed anything up recently. Kate: That's not like you, Janet.Janet:I know, but I lost my memory stick. I really should have backed things up. How stupid of me not to do that! Supposing I've lost everything!Mark: Let me take a look. The power is still on. And also the operating system still seems to be working ...I think it has to be the graphics card ... But maybe that's not the problem ...Janet: If only I'd backed things up!Kate: Relax, Janet! We'll take it to the computer shop this afternoon. I'm sure it'll be OK.Janet: I hope so.Unit 6-Conversation 2Janet: Tell me about Alice in Wonderland.Kate: I tell you what, I'll read it to you. Kate: Alice was beginning to get very tired of sitting by her sister on the bank and having nothing to do: Once or twice, she had peeped into the book her sister was reading, but it had no pictures or conversations in it, "and what is the use of a book," thought Alice, "without pictures or conversation" So she was considering in her own mind (as well as she could, for the hot day made her feel very sleepy and stupid) ...Janet: Kate, Mark, where are you going You've got my laptop!Kate: It's all right, Janet, we're taking it to the computer shop. We'll be back soon.Mark: It's not like Janet to forget to back up her work.Kate: She should have been more careful.Janet: It was stupid of me, I know! Stupid, stupid! Janet: Oh! It was a dream! What a relief!Kate: You were talking in your sleep.Janet: What was I sayingKate: "Stupid, stupid."M ark: I've sorted out your computer.Janet: Have you Oh, thank goodness! What was the problemMark:It was the graphics card, as I predicted ... Janet: Is that what it was! I'm so relieved! Thanks, Mark.Kate: He's great, isn't heJanet: Yes. So are you, Kate.Kate: You're such a good friend.Unit 6-Outside viewComputers are a very important part of our lives. They tell us about delays to transport. They drive trains, analyze evidence and control buildings. Did you know that 60 per cent of homes in Britain have got a PC (a personal computer) For many young people, playing computer games is their favorite way of spending spare time. Computers are a very important part of most areas of life in Britain-libraries, the police and in school. But they are becoming more important in our homes as well. They’ll even control the way we live-in “smart homes” or computer-controlled houses. The smart home is now a real possibility. It will become very common. A central computer will adjust the temperature, act as a burglar alarm and switch on lights, ready for you to come back home. And of course you will be able to give new instructions to the computer from your mobile phone. So if your plans change, your home will react to match. Many homes have got lots of televisions and several computers. The smart home will provide TV and Internet sockets in every room, so you’ll be able to do what you want whenever you want. If the temperature outside changes, the smart home will adjust the temperature levels inside. The computer will also close the blinds when it gets dark or to stop so much sun from entering a room. And if you want to eat when you get home, the computer will turn the oven on for you! Are computers taking over our lives In a survey, 44 per cent of young people between 11 and 16 said their PC was a trusted friend. Twenty per cent said they were happier at their computer than spending time with family or friends. Another survey found that people in Britain spend so much time on the phone, texting and reading emails that they no longer have time for conversation. What do you think about thatUnit 6-Listening inNews ReportUS Scientists have announced the discovery of gravitational waves, which are tiny waves produced by massive objects moving very quickly. Two black holes produced the waves when they crashed into each other about billion years ago. A black hole is a place in space where the gravity is so strong that even light cannot escape. This announcement of the discovery comes a century after Albert Einstein first predicted gravitational waves would exist.The discovery was made possible by using a highly sensitive instrument designed to detect signals of gravitational waves and identify their sources. This discovery proves that there are gravitational waves, and strongly confirms the existence of black holes.With this discovery, scientists are given a new tool to study and understand the universe. The waves could help scientists learn more about what happened immediately after the universe began and how the universe expanded. Scientists hope that they may be able to observe parts of the universe that were previously undetectable.1.What discovery have US scientists made2.What features do black holes have according to thenews report3.Why is the discovery importantPassage 1When you have a biscuit with your cup of tea, do you dunk it And if so, what’s the perfect way to do it That’s the subject of today’s Science in Action report. It may be hard to believe but scientists at the University of Bristol have been analyzing this question. And after a two-month study they devised a mathematical formula for dunking biscuits. So no more melting chocolate, or biscuit crumbs in the bottom of your cup, which is the fate of one in four biscuits that are dunked in tea, according to research by a biscuit manufacturer. Doughnut dunkers don’t face the same problems because doughnuts are held together with an elastic net of protein, gluten. This substance allows the doughnut to absorb liquid without breaking down its structure. The structure of a biscuit, however, is held together by sugar which melts when placed in hot tea or coffee.So what is the answer The researcher, let by Dr. Len Fisher, discovered that holding the biscuit in a horizontal position – or “flat-on”– has a significant effect on the amount of time that a biscuit can stay in hot liquid before falling apart. In fact this horizontal dunking results in a dunking time up to four times longer than traditional vertical dunking.What’s the reason for this It seems that the answer is related to diffusion, in other words, the length of time it takes for the liquid to penetrate the structure of the biscuit. Basically, it takes longer for the liquid to travel through the channels of a biscuit when it is laid flat on the surface of the liquid. Also the fact that when a biscuit is dunked horizontally, with the biscuit submerged in the liquid, and the chocolate coating staying out of the liquid, the chocolate helps hold the biscuit together. Another factor influencing the equation is the temperature of the tea –the hotter the tea, the faster the sugar melts.Researchers also found that by dunking a biscuit into tea or coffee, up to ten times more flavor is release than it the b iscuit is eaten dry. So it’s worth experimenting yourself. If you are wondering how you can perfect the horizontal dunk, the researchers have come up with an idea for a biscuit-holding device to make dunking biscuits easier. They are even mow working on producing a table giving guidelines on dunking times for different types of biscuit. On that note, I think it’s time to go off to the canteen for a tea break!Passage 2Peter: Hey Louise, look at this book about crop circles - some of the photos are absolutelyunbelievable.Louise: You don t believe in all that stuff, do you PeterPeter: I'm not saying I believe in UFOs and things, but some of the formations are fascinating.They’re made up of lots of interconnectedcircles and geometrical shapes. You know, inthe past few years, there have been morereports of them. The circles are gettinglarger and the designs are getting moreintricate... I'm sure that they can't all beman-made. Think about it - they're socomplicated, and they appear at night in themiddle of fields of wheat barley or corn.It’s definitely pretty weird!Louise: I know, but l saw a TV documentary about it, and they showed how a group of hoaxers madean elaborate crop circle in a field at nightusing wooden plank, ropes, plastic tubes anda garden roller. They even fooled some of thepeople who believe in the paranormal-alienscoming down in UFOs and aliens coming downin UFOs and creating them, and so on. Peter: I'm sure lots of them are created by people just to get publicity but look here-it says,“The first records of crop circles go backas far as the 17th century. Since the 1970sthere have been over 12,000 reports fromcountries all around the world includingItaly, America, South Africa, Australia andBrazil.” Most reports are from here inEngland though.Louise: B ut surely that’s just because they get so much media coverage these days, so morepeople are making them.Peter: Perhaps, but how do you explain the fact that the actual chemical composition of thegrains of corps inside the circles changesScientific tests have found they have ahigher protein level. The stems of the grainshave often been exposed to high temperatures.And they found that the soil within thecircles contains more iron than the soiloutside. So far, the hoaxers haven't beenable to copy all these features.Louise: W ell, I'm not a scientist but I'm pretty sceptical about all these so-calledparanormal explanations. I remember in theprogramme I watched, the researchers foundsigns of human interference, such as holesin the earth and footprints!Peter: Come on… you must admit, that still leavesa lot which is unexplained!Louise: T here's lots of things that are hard to explain but this really...。
gw振动值
GW振动值1. 引言GW振动值是指引力波（Gravitational Waves，GW）信号的振动强度。
引力波是由质量分布不均匀的物体在加速运动时产生的时空弯曲所导致的。
它们是爱因斯坦广义相对论的预测，并在2015年首次被直接探测到。
GW振动值是评估引力波信号的强度和频率特征的重要指标，对于理解宇宙的演化、探索黑洞等天体物理现象具有重要意义。
2. GW振动值的计算方法GW振动值的计算是通过对引力波信号进行分析和处理得到的。
一般来说，计算GW 振动值的过程包括以下几个步骤：2.1 数据采集首先，需要从引力波探测器中采集到原始数据。
目前常用的引力波探测器有激光干涉引力波天文台（LIGO）、欧洲引力波天文台（Virgo）等。
这些探测器能够测量到非常微小的长度变化，从而探测到引力波信号。
2.2 信号处理采集到的原始数据需要进行信号处理，以提取出引力波信号。
这一步骤包括滤波、降噪等处理过程，以消除噪声并突出引力波信号。
2.3 频谱分析在信号处理之后，需要对信号进行频谱分析。
频谱分析可以将信号分解为不同频率的成分，从而得到引力波信号的频率特征。
2.4 振动值计算最后，根据频谱分析的结果，可以计算出引力波信号的振动值。
振动值一般用于描述引力波信号的强度，通常是以能量或者振幅的形式表示。
3. GW振动值的意义和应用GW振动值是研究引力波信号的重要指标，具有以下意义和应用：3.1 宇宙学研究通过观测和分析引力波信号的振动值，可以获得关于宇宙演化和结构形成的重要信息。
引力波信号可以揭示宇宙的起源、演化过程以及宇宙中暗物质和暗能量等未知物质的性质。
3.2 天体物理研究引力波信号的振动值可以提供有关天体物理现象的重要信息。
例如，通过对黑洞和中子星碰撞产生的引力波信号的振动值进行研究，可以更好地理解这些天体的性质和行为。
3.3 引力波探测技术改进GW振动值的研究可以帮助改进引力波探测技术。
通过对引力波信号的振动值进行分析，可以优化探测器的设计和性能，提高引力波信号的探测灵敏度。
土壤学考试名词解释
绪论土壤（Soil ）：陆地表面由矿物质、有机物质、水、空气和生物组成，具有肥力，能生长植物的未固结层。
物的未固结层。
土壤肥力（soil fertility ）：土壤能供应与协调植物正常生长发育所需的养分和水、气、热的能力。
能力。
是土壤的基本属性和质的特征。
是土壤的基本属性和质的特征。
第一章1、同晶替代/同晶代换/同晶置换/同型异质替代/ Isomorphous substitution 组成矿物的中心离子被电性相同、大小相近的离子所替代而晶格构造保持不变的现象。
第二章1、名词解释、名词解释土壤有机质（Soil organic matter ，SOM ）是指存在于土壤中的所有含碳的有机物，包括各种动植物残体，微生物体及其分解和合成的各类有机物质。
土壤腐殖质（humus ）是除未分解和半分解动、植物残体及微生物体以外的有机物质的总称。
矿化作用(mineralization) 土壤有机质在土壤微生物及其酶的作用下，氧化分解成二氧化碳和水，并释放出其中的矿质养分的过程。
和水，并释放出其中的矿质养分的过程。
冻土效应(effect of soil freezing) 土壤冰冻以后，在其解冻后的最初1~2周内，二氧化碳和氨释放量增多的现象。
释放量增多的现象。
干土效应（ effect of soil drying ）：土壤经过干燥后，在加水湿润的最初1~2周内，二氧化碳和氨释放量增加的现象。
碳和氨释放量增加的现象。
腐殖化过程:(Humification) 动物、植物、微生物残体在微生物作用下，通过生化和化学作用而形成腐殖质的过程。
激发效应**（Priming effect)：投入新鲜有机质或含氮物质而使土壤中原有机物质的分解速率改变的现象。
使分解速率增加的称正激发效应；降低的称负激发效应。
HA/FA 值：表示胡敏酸与富里酸含量的比值。
是表示土壤腐殖质成份变异的指标之一。
第三章 根际效应: 根际土壤与非根际土壤在物理、根际土壤与非根际土壤在物理、化学和生物学特性有明显的不同，化学和生物学特性有明显的不同，化学和生物学特性有明显的不同，这些特征在根这些特征在根际土壤和非根际土壤的比值称为根土比(R/S ratio)。
引力波观测原文PhysRevLett.116.061102
Observation of Gravitational Waves from a Binary Black Hole MergerB.P.Abbott et al.*(LIGO Scientific Collaboration and Virgo Collaboration)(Received21January2016;published11February2016)On September14,2015at09:50:45UTC the two detectors of the Laser Interferometer Gravitational-Wave Observatory simultaneously observed a transient gravitational-wave signal.The signal sweeps upwards in frequency from35to250Hz with a peak gravitational-wave strain of1.0×10−21.It matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole.The signal was observed with a matched-filter signal-to-noise ratio of24and a false alarm rate estimated to be less than1event per203000years,equivalent to a significance greaterthan5.1σ.The source lies at a luminosity distance of410þ160−180Mpc corresponding to a redshift z¼0.09þ0.03−0.04.In the source frame,the initial black hole masses are36þ5−4M⊙and29þ4−4M⊙,and the final black hole mass is62þ4−4M⊙,with3.0þ0.5−0.5M⊙c2radiated in gravitational waves.All uncertainties define90%credible intervals.These observations demonstrate the existence of binary stellar-mass black hole systems.This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.DOI:10.1103/PhysRevLett.116.061102I.INTRODUCTIONIn1916,the year after the final formulation of the field equations of general relativity,Albert Einstein predicted the existence of gravitational waves.He found that the linearized weak-field equations had wave solutions: transverse waves of spatial strain that travel at the speed of light,generated by time variations of the mass quadrupole moment of the source[1,2].Einstein understood that gravitational-wave amplitudes would be remarkably small;moreover,until the Chapel Hill conference in 1957there was significant debate about the physical reality of gravitational waves[3].Also in1916,Schwarzschild published a solution for the field equations[4]that was later understood to describe a black hole[5,6],and in1963Kerr generalized the solution to rotating black holes[7].Starting in the1970s theoretical work led to the understanding of black hole quasinormal modes[8–10],and in the1990s higher-order post-Newtonian calculations[11]preceded extensive analytical studies of relativistic two-body dynamics[12,13].These advances,together with numerical relativity breakthroughs in the past decade[14–16],have enabled modeling of binary black hole mergers and accurate predictions of their gravitational waveforms.While numerous black hole candidates have now been identified through electromag-netic observations[17–19],black hole mergers have not previously been observed.The discovery of the binary pulsar system PSR B1913þ16 by Hulse and Taylor[20]and subsequent observations of its energy loss by Taylor and Weisberg[21]demonstrated the existence of gravitational waves.This discovery, along with emerging astrophysical understanding[22], led to the recognition that direct observations of the amplitude and phase of gravitational waves would enable studies of additional relativistic systems and provide new tests of general relativity,especially in the dynamic strong-field regime.Experiments to detect gravitational waves began with Weber and his resonant mass detectors in the1960s[23], followed by an international network of cryogenic reso-nant detectors[24].Interferometric detectors were first suggested in the early1960s[25]and the1970s[26].A study of the noise and performance of such detectors[27], and further concepts to improve them[28],led to proposals for long-baseline broadband laser interferome-ters with the potential for significantly increased sensi-tivity[29–32].By the early2000s,a set of initial detectors was completed,including TAMA300in Japan,GEO600 in Germany,the Laser Interferometer Gravitational-Wave Observatory(LIGO)in the United States,and Virgo in binations of these detectors made joint obser-vations from2002through2011,setting upper limits on a variety of gravitational-wave sources while evolving into a global network.In2015,Advanced LIGO became the first of a significantly more sensitive network of advanced detectors to begin observations[33–36].A century after the fundamental predictions of Einstein and Schwarzschild,we report the first direct detection of gravitational waves and the first direct observation of a binary black hole system merging to form a single black hole.Our observations provide unique access to the*Full author list given at the end of the article.Published by the American Physical Society under the terms of the Creative Commons Attribution3.0License.Further distri-bution of this work must maintain attribution to the author(s)and the published article’s title,journal citation,and DOI.properties of space-time in the strong-field,high-velocity regime and confirm predictions of general relativity for the nonlinear dynamics of highly disturbed black holes.II.OBSERVATIONOn September14,2015at09:50:45UTC,the LIGO Hanford,W A,and Livingston,LA,observatories detected the coincident signal GW150914shown in Fig.1.The initial detection was made by low-latency searches for generic gravitational-wave transients[41]and was reported within three minutes of data acquisition[43].Subsequently, matched-filter analyses that use relativistic models of com-pact binary waveforms[44]recovered GW150914as the most significant event from each detector for the observa-tions reported here.Occurring within the10-msintersite FIG.1.The gravitational-wave event GW150914observed by the LIGO Hanford(H1,left column panels)and Livingston(L1,rightcolumn panels)detectors.Times are shown relative to September14,2015at09:50:45UTC.For visualization,all time series are filtered with a35–350Hz bandpass filter to suppress large fluctuations outside the detectors’most sensitive frequency band,and band-reject filters to remove the strong instrumental spectral lines seen in the Fig.3spectra.Top row,left:H1strain.Top row,right:L1strain.GW150914arrived first at L1and6.9þ0.5−0.4ms later at H1;for a visual comparison,the H1data are also shown,shifted in time by this amount and inverted(to account for the detectors’relative orientations).Second row:Gravitational-wave strain projected onto each detector in the35–350Hz band.Solid lines show a numerical relativity waveform for a system with parameters consistent with those recovered from GW150914[37,38]confirmed to99.9%by an independent calculation based on[15].Shaded areas show90%credible regions for two independent waveform reconstructions.One(dark gray)models the signal using binary black hole template waveforms [39].The other(light gray)does not use an astrophysical model,but instead calculates the strain signal as a linear combination of sine-Gaussian wavelets[40,41].These reconstructions have a94%overlap,as shown in[39].Third row:Residuals after subtracting the filtered numerical relativity waveform from the filtered detector time series.Bottom row:A time-frequency representation[42]of the strain data,showing the signal frequency increasing over time.propagation time,the events have a combined signal-to-noise ratio(SNR)of24[45].Only the LIGO detectors were observing at the time of GW150914.The Virgo detector was being upgraded, and GEO600,though not sufficiently sensitive to detect this event,was operating but not in observational mode.With only two detectors the source position is primarily determined by the relative arrival time and localized to an area of approximately600deg2(90% credible region)[39,46].The basic features of GW150914point to it being produced by the coalescence of two black holes—i.e., their orbital inspiral and merger,and subsequent final black hole ringdown.Over0.2s,the signal increases in frequency and amplitude in about8cycles from35to150Hz,where the amplitude reaches a maximum.The most plausible explanation for this evolution is the inspiral of two orbiting masses,m1and m2,due to gravitational-wave emission.At the lower frequencies,such evolution is characterized by the chirp mass[11]M¼ðm1m2Þ3=5121=5¼c3G596π−8=3f−11=3_f3=5;where f and_f are the observed frequency and its time derivative and G and c are the gravitational constant and speed of light.Estimating f and_f from the data in Fig.1, we obtain a chirp mass of M≃30M⊙,implying that the total mass M¼m1þm2is≳70M⊙in the detector frame. This bounds the sum of the Schwarzschild radii of thebinary components to2GM=c2≳210km.To reach an orbital frequency of75Hz(half the gravitational-wave frequency)the objects must have been very close and very compact;equal Newtonian point masses orbiting at this frequency would be only≃350km apart.A pair of neutron stars,while compact,would not have the required mass,while a black hole neutron star binary with the deduced chirp mass would have a very large total mass, and would thus merge at much lower frequency.This leaves black holes as the only known objects compact enough to reach an orbital frequency of75Hz without contact.Furthermore,the decay of the waveform after it peaks is consistent with the damped oscillations of a black hole relaxing to a final stationary Kerr configuration. Below,we present a general-relativistic analysis of GW150914;Fig.2shows the calculated waveform using the resulting source parameters.III.DETECTORSGravitational-wave astronomy exploits multiple,widely separated detectors to distinguish gravitational waves from local instrumental and environmental noise,to provide source sky localization,and to measure wave polarizations. The LIGO sites each operate a single Advanced LIGO detector[33],a modified Michelson interferometer(see Fig.3)that measures gravitational-wave strain as a differ-ence in length of its orthogonal arms.Each arm is formed by two mirrors,acting as test masses,separated by L x¼L y¼L¼4km.A passing gravitational wave effec-tively alters the arm lengths such that the measured difference isΔLðtÞ¼δL x−δL y¼hðtÞL,where h is the gravitational-wave strain amplitude projected onto the detector.This differential length variation alters the phase difference between the two light fields returning to the beam splitter,transmitting an optical signal proportional to the gravitational-wave strain to the output photodetector. To achieve sufficient sensitivity to measure gravitational waves,the detectors include several enhancements to the basic Michelson interferometer.First,each arm contains a resonant optical cavity,formed by its two test mass mirrors, that multiplies the effect of a gravitational wave on the light phase by a factor of300[48].Second,a partially trans-missive power-recycling mirror at the input provides addi-tional resonant buildup of the laser light in the interferometer as a whole[49,50]:20W of laser input is increased to700W incident on the beam splitter,which is further increased to 100kW circulating in each arm cavity.Third,a partially transmissive signal-recycling mirror at the outputoptimizes FIG. 2.Top:Estimated gravitational-wave strain amplitude from GW150914projected onto H1.This shows the full bandwidth of the waveforms,without the filtering used for Fig.1. The inset images show numerical relativity models of the black hole horizons as the black holes coalesce.Bottom:The Keplerian effective black hole separation in units of Schwarzschild radii (R S¼2GM=c2)and the effective relative velocity given by the post-Newtonian parameter v=c¼ðGMπf=c3Þ1=3,where f is the gravitational-wave frequency calculated with numerical relativity and M is the total mass(value from Table I).the gravitational-wave signal extraction by broadening the bandwidth of the arm cavities [51,52].The interferometer is illuminated with a 1064-nm wavelength Nd:Y AG laser,stabilized in amplitude,frequency,and beam geometry [53,54].The gravitational-wave signal is extracted at the output port using a homodyne readout [55].These interferometry techniques are designed to maxi-mize the conversion of strain to optical signal,thereby minimizing the impact of photon shot noise (the principal noise at high frequencies).High strain sensitivity also requires that the test masses have low displacement noise,which is achieved by isolating them from seismic noise (low frequencies)and designing them to have low thermal noise (intermediate frequencies).Each test mass is suspended as the final stage of a quadruple-pendulum system [56],supported by an active seismic isolation platform [57].These systems collectively provide more than 10orders of magnitude of isolation from ground motion for frequen-cies above 10Hz.Thermal noise is minimized by using low-mechanical-loss materials in the test masses and their suspensions:the test masses are 40-kg fused silica substrates with low-loss dielectric optical coatings [58,59],and are suspended with fused silica fibers from the stage above [60].To minimize additional noise sources,all components other than the laser source are mounted on vibration isolation stages in ultrahigh vacuum.To reduce optical phase fluctuations caused by Rayleigh scattering,the pressure in the 1.2-m diameter tubes containing the arm-cavity beams is maintained below 1μPa.Servo controls are used to hold the arm cavities on resonance [61]and maintain proper alignment of the optical components [62].The detector output is calibrated in strain by measuring its response to test mass motion induced by photon pressure from a modulated calibration laser beam [63].The calibration is established to an uncertainty (1σ)of less than 10%in amplitude and 10degrees in phase,and is continuously monitored with calibration laser excitations at selected frequencies.Two alternative methods are used to validate the absolute calibration,one referenced to the main laser wavelength and the other to a radio-frequencyoscillator(a)FIG.3.Simplified diagram of an Advanced LIGO detector (not to scale).A gravitational wave propagating orthogonally to the detector plane and linearly polarized parallel to the 4-km optical cavities will have the effect of lengthening one 4-km arm and shortening the other during one half-cycle of the wave;these length changes are reversed during the other half-cycle.The output photodetector records these differential cavity length variations.While a detector ’s directional response is maximal for this case,it is still significant for most other angles of incidence or polarizations (gravitational waves propagate freely through the Earth).Inset (a):Location and orientation of the LIGO detectors at Hanford,WA (H1)and Livingston,LA (L1).Inset (b):The instrument noise for each detector near the time of the signal detection;this is an amplitude spectral density,expressed in terms of equivalent gravitational-wave strain amplitude.The sensitivity is limited by photon shot noise at frequencies above 150Hz,and by a superposition of other noise sources at lower frequencies [47].Narrow-band features include calibration lines (33–38,330,and 1080Hz),vibrational modes of suspension fibers (500Hz and harmonics),and 60Hz electric power grid harmonics.[64].Additionally,the detector response to gravitational waves is tested by injecting simulated waveforms with the calibration laser.To monitor environmental disturbances and their influ-ence on the detectors,each observatory site is equipped with an array of sensors:seismometers,accelerometers, microphones,magnetometers,radio receivers,weather sensors,ac-power line monitors,and a cosmic-ray detector [65].Another∼105channels record the interferometer’s operating point and the state of the control systems.Data collection is synchronized to Global Positioning System (GPS)time to better than10μs[66].Timing accuracy is verified with an atomic clock and a secondary GPS receiver at each observatory site.In their most sensitive band,100–300Hz,the current LIGO detectors are3to5times more sensitive to strain than initial LIGO[67];at lower frequencies,the improvement is even greater,with more than ten times better sensitivity below60Hz.Because the detectors respond proportionally to gravitational-wave amplitude,at low redshift the volume of space to which they are sensitive increases as the cube of strain sensitivity.For binary black holes with masses similar to GW150914,the space-time volume surveyed by the observations reported here surpasses previous obser-vations by an order of magnitude[68].IV.DETECTOR VALIDATIONBoth detectors were in steady state operation for several hours around GW150914.All performance measures,in particular their average sensitivity and transient noise behavior,were typical of the full analysis period[69,70]. Exhaustive investigations of instrumental and environ-mental disturbances were performed,giving no evidence to suggest that GW150914could be an instrumental artifact [69].The detectors’susceptibility to environmental disturb-ances was quantified by measuring their response to spe-cially generated magnetic,radio-frequency,acoustic,and vibration excitations.These tests indicated that any external disturbance large enough to have caused the observed signal would have been clearly recorded by the array of environ-mental sensors.None of the environmental sensors recorded any disturbances that evolved in time and frequency like GW150914,and all environmental fluctuations during the second that contained GW150914were too small to account for more than6%of its strain amplitude.Special care was taken to search for long-range correlated disturbances that might produce nearly simultaneous signals at the two sites. No significant disturbances were found.The detector strain data exhibit non-Gaussian noise transients that arise from a variety of instrumental mecha-nisms.Many have distinct signatures,visible in auxiliary data channels that are not sensitive to gravitational waves; such instrumental transients are removed from our analyses [69].Any instrumental transients that remain in the data are accounted for in the estimated detector backgrounds described below.There is no evidence for instrumental transients that are temporally correlated between the two detectors.V.SEARCHESWe present the analysis of16days of coincident observations between the two LIGO detectors from September12to October20,2015.This is a subset of the data from Advanced LIGO’s first observational period that ended on January12,2016.GW150914is confidently detected by two different types of searches.One aims to recover signals from the coalescence of compact objects,using optimal matched filtering with waveforms predicted by general relativity. The other search targets a broad range of generic transient signals,with minimal assumptions about waveforms.These searches use independent methods,and their response to detector noise consists of different,uncorrelated,events. However,strong signals from binary black hole mergers are expected to be detected by both searches.Each search identifies candidate events that are detected at both observatories consistent with the intersite propa-gation time.Events are assigned a detection-statistic value that ranks their likelihood of being a gravitational-wave signal.The significance of a candidate event is determined by the search background—the rate at which detector noise produces events with a detection-statistic value equal to or higher than the candidate event.Estimating this back-ground is challenging for two reasons:the detector noise is nonstationary and non-Gaussian,so its properties must be empirically determined;and it is not possible to shield the detector from gravitational waves to directly measure a signal-free background.The specific procedure used to estimate the background is slightly different for the two searches,but both use a time-shift technique:the time stamps of one detector’s data are artificially shifted by an offset that is large compared to the intersite propagation time,and a new set of events is produced based on this time-shifted data set.For instrumental noise that is uncor-related between detectors this is an effective way to estimate the background.In this process a gravitational-wave signal in one detector may coincide with time-shifted noise transients in the other detector,thereby contributing to the background estimate.This leads to an overestimate of the noise background and therefore to a more conservative assessment of the significance of candidate events.The characteristics of non-Gaussian noise vary between different time-frequency regions.This means that the search backgrounds are not uniform across the space of signals being searched.To maximize sensitivity and provide a better estimate of event significance,the searches sort both their background estimates and their event candidates into differ-ent classes according to their time-frequency morphology. The significance of a candidate event is measured against the background of its class.To account for having searchedmultiple classes,this significance is decreased by a trials factor equal to the number of classes [71].A.Generic transient searchDesigned to operate without a specific waveform model,this search identifies coincident excess power in time-frequency representations of the detector strain data [43,72],for signal frequencies up to 1kHz and durations up to a few seconds.The search reconstructs signal waveforms consistent with a common gravitational-wave signal in both detectors using a multidetector maximum likelihood method.Each event is ranked according to the detection statistic ηc ¼ffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffiffi2E c =ð1þE n =E c Þp ,where E c is the dimensionless coherent signal energy obtained by cross-correlating the two reconstructed waveforms,and E n is the dimensionless residual noise energy after the reconstructed signal is subtracted from the data.The statistic ηc thus quantifies the SNR of the event and the consistency of the data between the two detectors.Based on their time-frequency morphology,the events are divided into three mutually exclusive search classes,as described in [41]:events with time-frequency morphology of known populations of noise transients (class C1),events with frequency that increases with time (class C3),and all remaining events (class C2).Detected with ηc ¼20.0,GW150914is the strongest event of the entire search.Consistent with its coalescence signal signature,it is found in the search class C3of events with increasing time-frequency evolution.Measured on a background equivalent to over 67400years of data and including a trials factor of 3to account for the search classes,its false alarm rate is lower than 1in 22500years.This corresponds to a probability <2×10−6of observing one or more noise events as strong as GW150914during the analysis time,equivalent to 4.6σ.The left panel of Fig.4shows the C3class results and background.The selection criteria that define the search class C3reduce the background by introducing a constraint on the signal morphology.In order to illustrate the significance of GW150914against a background of events with arbitrary shapes,we also show the results of a search that uses the same set of events as the one described above but without this constraint.Specifically,we use only two search classes:the C1class and the union of C2and C3classes (C 2þC 3).In this two-class search the GW150914event is found in the C 2þC 3class.The left panel of Fig.4shows the C 2þC 3class results and background.In the background of this class there are four events with ηc ≥32.1,yielding a false alarm rate for GW150914of 1in 8400years.This corresponds to a false alarm probability of 5×10−6equivalent to 4.4σ.FIG.4.Search results from the generic transient search (left)and the binary coalescence search (right).These histograms show the number of candidate events (orange markers)and the mean number of background events (black lines)in the search class where GW150914was found as a function of the search detection statistic and with a bin width of 0.2.The scales on the top give the significance of an event in Gaussian standard deviations based on the corresponding noise background.The significance of GW150914is greater than 5.1σand 4.6σfor the binary coalescence and the generic transient searches,respectively.Left:Along with the primary search (C3)we also show the results (blue markers)and background (green curve)for an alternative search that treats events independently of their frequency evolution (C 2þC 3).The classes C2and C3are defined in the text.Right:The tail in the black-line background of the binary coalescence search is due to random coincidences of GW150914in one detector with noise in the other detector.(This type of event is practically absent in the generic transient search background because they do not pass the time-frequency consistency requirements used in that search.)The purple curve is the background excluding those coincidences,which is used to assess the significance of the second strongest event.For robustness and validation,we also use other generic transient search algorithms[41].A different search[73]and a parameter estimation follow-up[74]detected GW150914 with consistent significance and signal parameters.B.Binary coalescence searchThis search targets gravitational-wave emission from binary systems with individual masses from1to99M⊙, total mass less than100M⊙,and dimensionless spins up to 0.99[44].To model systems with total mass larger than 4M⊙,we use the effective-one-body formalism[75],whichcombines results from the post-Newtonian approach [11,76]with results from black hole perturbation theory and numerical relativity.The waveform model[77,78] assumes that the spins of the merging objects are alignedwith the orbital angular momentum,but the resultingtemplates can,nonetheless,effectively recover systemswith misaligned spins in the parameter region ofGW150914[44].Approximately250000template wave-forms are used to cover this parameter space.The search calculates the matched-filter signal-to-noiseratioρðtÞfor each template in each detector and identifiesmaxima ofρðtÞwith respect to the time of arrival of the signal[79–81].For each maximum we calculate a chi-squared statisticχ2r to test whether the data in several differentfrequency bands are consistent with the matching template [82].Values ofχ2r near unity indicate that the signal is consistent with a coalescence.Ifχ2r is greater than unity,ρðtÞis reweighted asˆρ¼ρ=f½1þðχ2rÞ3 =2g1=6[83,84].The final step enforces coincidence between detectors by selectingevent pairs that occur within a15-ms window and come fromthe same template.The15-ms window is determined by the10-ms intersite propagation time plus5ms for uncertainty inarrival time of weak signals.We rank coincident events basedon the quadrature sumˆρc of theˆρfrom both detectors[45]. To produce background data for this search the SNR maxima of one detector are time shifted and a new set of coincident events is computed.Repeating this procedure ∼107times produces a noise background analysis time equivalent to608000years.To account for the search background noise varying acrossthe target signal space,candidate and background events aredivided into three search classes based on template length.The right panel of Fig.4shows the background for thesearch class of GW150914.The GW150914detection-statistic value ofˆρc¼23.6is larger than any background event,so only an upper bound can be placed on its false alarm rate.Across the three search classes this bound is1in 203000years.This translates to a false alarm probability <2×10−7,corresponding to5.1σ.A second,independent matched-filter analysis that uses adifferent method for estimating the significance of itsevents[85,86],also detected GW150914with identicalsignal parameters and consistent significance.When an event is confidently identified as a real gravitational-wave signal,as for GW150914,the back-ground used to determine the significance of other events is reestimated without the contribution of this event.This is the background distribution shown as a purple line in the right panel of Fig.4.Based on this,the second most significant event has a false alarm rate of1per2.3years and corresponding Poissonian false alarm probability of0.02. Waveform analysis of this event indicates that if it is astrophysical in origin it is also a binary black hole merger[44].VI.SOURCE DISCUSSIONThe matched-filter search is optimized for detecting signals,but it provides only approximate estimates of the source parameters.To refine them we use general relativity-based models[77,78,87,88],some of which include spin precession,and for each model perform a coherent Bayesian analysis to derive posterior distributions of the source parameters[89].The initial and final masses, final spin,distance,and redshift of the source are shown in Table I.The spin of the primary black hole is constrained to be<0.7(90%credible interval)indicating it is not maximally spinning,while the spin of the secondary is only weakly constrained.These source parameters are discussed in detail in[39].The parameter uncertainties include statistical errors and systematic errors from averaging the results of different waveform models.Using the fits to numerical simulations of binary black hole mergers in[92,93],we provide estimates of the mass and spin of the final black hole,the total energy radiated in gravitational waves,and the peak gravitational-wave luminosity[39].The estimated total energy radiated in gravitational waves is3.0þ0.5−0.5M⊙c2.The system reached apeak gravitational-wave luminosity of3.6þ0.5−0.4×1056erg=s,equivalent to200þ30−20M⊙c2=s.Several analyses have been performed to determine whether or not GW150914is consistent with a binary TABLE I.Source parameters for GW150914.We report median values with90%credible intervals that include statistical errors,and systematic errors from averaging the results of different waveform models.Masses are given in the source frame;to convert to the detector frame multiply by(1þz) [90].The source redshift assumes standard cosmology[91]. Primary black hole mass36þ5−4M⊙Secondary black hole mass29þ4−4M⊙Final black hole mass62þ4−4M⊙Final black hole spin0.67þ0.05−0.07 Luminosity distance410þ160−180MpcSource redshift z0.09þ0.03−0.04。
2022-2023学年江西省顶级名校高三下学期一模考试英语试题含解析
2023年高考英语模拟试卷注意事项：1．答卷前，考生务必将自己的姓名、准考证号填写在答题卡上。
2．回答选择题时，选出每小题答案后，用铅笔把答题卡上对应题目的答案标号涂黑，如需改动，用橡皮擦干净后，再选涂其它答案标号。
回答非选择题时，将答案写在答题卡上，写在本试卷上无效。
3．考试结束后，将本试卷和答题卡一并交回。
第一部分（共20小题，每小题1.5分，满分30分）1．I hope my teacher will take into _______ the fact that I was ill just before the exams when she marks my paper. A．idea B．considered C．account D．thought2．语音知识(共5小题；每小题l分，满分5分)从A、B、C、D四个选项中，找出其划线部分与所给单词的划线部分读音相同的选项。
并在答题卡上将该项涂黑。
3．Pandas are _____ to the mountains of central China and only about 1,000 remain in the wild.A. native B．sensitive C．relate D．familiar4．So absorbed ________ in her yoga exercises that she took no notice of the heavy rain outside.A．Mary was B．Mary has beenC．was Mary D．has Mary been5．______ property, we’re among the richest people in this city．A．In search of B．In spite of C．In place of D．In terms of6．We are to hold the sports meeting next weekend, ________ the air quality becomes better.A．which B．whenC．where D．while7．It is one thing to enjoy listening to good music, but it is quite ______ to perform skillfully yourself.A．another B．other C．the other D．others8．—What a shame! We misunderstood each other for such a long time.—Yes, I wish I _____ with you earlier.A．communicate B．had communicatedC．communicated D．would communicate9．During each NBA season, basketball fans cheer on their favorite teams to make _______ through.A．it B．themC．that D．those10．People tend to love agricultural products ________ without the use of fertilizers, pesticides or chemical additives. A．growing B．grownC．being grown D．having been grown11．It rained this morning, _____ actually didn’t bother me because I like walking in the rain.A．what B．whenC．where D．which12．The first snow didn’t fall until February in our province this year, ________ was unexpec ted.A．it B．which C．that D．what13．The disaster-stricken village was inaccessible ___________ by helicopter, and the storm added to the rescuers’ difficulty.A．instead of B．other than C．rather than D．regardless of14．—Did you enjoy your journey to Beijing last weekend?—. We had driven more than 3 hours before we found the right way.A．Absolutely B．No way C．Not at all D．With pleasure15．Regarding China-US differences on human rights issues, Hong said the two sides can enhance mutual understanding through dialogue ______ on equality and mutual respect.A．based B．to base C．basing D．base16．—Do you know when your mother ________ to pick you up?—At 11：40 am.A．had come B．is comingC．has come D．would come17．—Hi, Tom! I got a chance to be an exchange student in Harvard University.—_________! I had been expecting to study there.A．Lucky you B．Have funC．Take it easy D．Forget it18．The government officials met the workers and engineers working on the stadium, most____ were migrant workers．A．of which B．of who C．of whom D．of them19．—I’m sorry for breaking the cup.—Oh, ________. I’ve got plenty.A．help yourself B．forget itC．my pleasure D．pardon me20．—Got your driving license?—No. I too busy to have enough practice, so I didn’t take the driving test last week.A．was B．amC．have been D．had been第二部分阅读理解（满分40分）阅读下列短文，从每题所给的A、B、C、D四个选项中，选出最佳选项。
江苏省七校联盟2024学年高三考前热身英语试卷(含解析)
江苏省七校联盟2024学年高三考前热身英语试卷注意事项：1．答题前，考生先将自己的姓名、准考证号填写清楚，将条形码准确粘贴在考生信息条形码粘贴区。
2．选择题必须使用2B铅笔填涂；非选择题必须使用0．5毫米黑色字迹的签字笔书写，字体工整、笔迹清楚。
3．请按照题号顺序在各题目的答题区域内作答，超出答题区域书写的答案无效；在草稿纸、试题卷上答题无效。
4．保持卡面清洁，不要折叠，不要弄破、弄皱，不准使用涂改液、修正带、刮纸刀。
第一部分（共20小题，每小题1.5分，满分30分）1．She is stubborn in resisting his enquiries about the Moonstone _____ the degree that she makes it seem as if she does not want the mystery ______.A．on; to solve B．with; solvingC．for; being solved D．to; to be solved2．The dining room is clean and tidy, with a table already ______for a big meal．A. being laid B．laying C．to lay D．laid3．Most spending that results in debt is like a drug: a quick hit of pleasure that ______, only to drag you down for years to come.A．takes off B．wears off C．sets off D．shows off4．—You ought to have made an apology to Tom yesterday evening．—Yes, I know I __ __．A．ought to have B．have to C．should D．must have5．The new movie ________ to be one of the biggest money-makers of all time.A．pretends B．agrees C．promises D．declines6．Egyptian President decided to ______on Friday afternoon after an 18-day campaign against him, ending histhirty-year rule.A．step down B．break in C．break down D．step in7．---May I help you？You seem to be having some trouble.----____________，thanks. I think I can manage.A．No problem B．It's all rightC．ok D．No way8．Music treatment involves a specialist playing an instrument or sing ________ the patient’s mood.A．by means of B．with regard toC．in response to D．on account of9．-Are you ready for the history test tomorrow?-No,I wish I_____the clock back.A．had turned B．could turnC．will turn D．would have turned10．They felt ________ it was high tax and low income ________ contributed to the extreme misery of the working people at the bottom of the ladder.A．/；that B．that; whichC．that; what D．/; which11．China’s BeiDou Navigation Satellite System, whose positioning ________ will reach 2.5 meters by 2020, will soon provide services for more countries.A．accuracy B．categoryC．function D．reference12．She was so angry and spoke so fast that none of us understood ______ he said meant．A．that B．what C．that that D．what what13．I’m interested in a blue dress. Do you have any _______?A．convenient B．available C．possible D．personal14．According to the co mpany’s rule, one’s payment is ______ the work done, not to the time spent doing it.A．in proportion to B．in addition toC．in contrast to D．in regard to15．This raw chocolate tastes pretty delicious due to ______ amount of melted pure fresh cream.A．equal B．generous C．insufficient D．tiny16．The 2011 Australian Open was successfully held in city of Melbourne, big city in Australia.A．a; a B．the; a C．a; the D．the; the17．Never turn down a job because you think it’s too small. You don’t know _____ it can lead.A．how B．whereC．whether D．what18．The customs officers were insisting that suitcases should be opened and their contents _______ for closer inspection. A．laid out B．given out C．sent out D．picked out19．— What great changes have taken place in our city in the last few years!— Indeed, many high buildings have _______all over the city.A．wound up B．sprung up C．held up D．made up20．We ______ be careful with the words we say when we are angry.A．may B．can C．might D．should第二部分阅读理解（满分40分）阅读下列短文，从每题所给的A、B、C、D四个选项中，选出最佳选项。
电子信息工程专业英语翻译清华出版社English for IT and EE-03
随着时间的推移，人们认识到 随着时间的推移， 电场和磁场是电磁场这一整体 的两个部分。 的两个部分。
13
9
Once this electromagnetic field has been produced from a given charge distribution, other charged objects in this field will experience a force (in a similar way that planets experience a force in the gravitational field of the Sun). If these other charges and currents are comparable in size to the sources producing the above electromagnetic field, then a new net electromagnetic field will be produced.3 如果另外这些电荷和电流的大小与 产生上述电磁场的源是可比的， 产生上述电磁场的源是可比的，那 么将产生一个新的净电磁场。 么将产生一个新的净电磁场。 电磁场中其它带电 体就会受到一个力 的作用
3
1
The electromagnetic field is a physical field produced by electrically charged objects. It affects the behavior of charged objects in the vicinity of the field. The electromagnetic field extends indefinitely throughout space and describes the electromagnetic interaction. It is one of the four fundamental forces in the nature (the others are gravitation, the weak interaction, and the strong interaction) 电磁场在空间无限延伸， 电磁场在空间无限延伸， 并描述电磁相互作用。 并描述电磁相互作用。
引力波(gravitational waves)
引力波Gravitational Waves[,ɡrævɪ'teɪʃənəl]❶100年前，爱因斯坦在他的广义相对论（General Theory of Relativity）里首次提到引力波（gravitational waves）。
❷如果把宇宙想象成一个巨大的蹦床（trampoline），这个蹦床的布料材质就是时空（space-time）。
引力波就是在这个时空蹦床中泛起的涟漪（ripples）。
把一个保龄球和一个乒乓球分别放在这个蹦床上，哪个会沉得深一些？没错！宇宙中也是如此：质量越大的物体产生的时空弯曲就越大（the more mass, the more space-time gets bent and distorted）。
❸将一个保龄球放在蹦床上，周围的时空因其质量而发生了弯曲，这时，一个乒乓球如果要在保龄球周围运行，就必然围绕其旋转，轨道（orbit）就是这么来的。
所以，按照广义相对论的思路，“引力”（gravity）只是时空扭曲带来的必然现象。
❹当两个巨大物质朝着彼此高速旋转时（spiral toward each other），它们就会以光速在周围扭曲的时空中传播出一波一波的涟漪（they send waves along the curved space-time around them at the speed of light）。
质量越大的物体，产生的引力波就越大，也就越容易被科学家探测到。
The more massive the object, the larger the wave and the easier for scientists to detect.❺通常引力波的产生非常困难。
地球围绕太阳以每秒30千米的速度前进，发出的引力波功率仅为200瓦，还不如家用电饭煲功率大。
宇宙中大质量天体的加速（accelerate）、碰撞（collide）和合并（coalesce）等事件才可以形成强大的引力波。
Einstein-Rosen, On Gravitational Waves(1937)
We consider t h a t the g., are replaced by the expressions where
g., = a., + u.,,
~,v = I
(2)
=o
if if
/~ = v. ~¢v,
provided we take the time co6rdinate imaginary, as was dotLo by Minkowski. It is assumed t h a t the %. are smal, i.e. t h a t the gravitational field is weak. In the equatiors the 3`.. and their derivatives will occur in various powers. If the 3`.. are everywhere sufficiently small compared to uaity one obtains a first-approximation solution of the equations by neglecting in (I) the higher powers of the 3`.. (~nd their derivatives) compared with the lower ones. If one introduces further the ~., instead of the 3`.. by the relations
/
ON GRAVITATIONAL WAVES.
BY A. E I N S T E I N and N. R O S E N .
英国中学GCSE单词物理词汇(带音标)
movement['muvmənt]运动、活动position[pə'zɪʃən]位置、方位acceleration[ək'sɛlə'reʃən]加速、促进velocity[və'lɑsəti] <力>速率、迅速investigate[in'vestigeit]调查、研究force[fɔrs]力量、促使weight[weit]重量、重力、负荷、使...变重friction['frɪkʃən]摩擦、<力>摩擦力precise[pri'sais]精确的、准确的accurate['ækjərət]精确的、准确的tape measure[teɪp] ['meʒə]卷尺vemier calliper['kælɪpə]游标卡尺micrometer screw gauge[maɪ'krɒmɪtə] [skruː] [geɪdʒ]螺旋千分尺{测微计} measuring cylinder['sɪlɪndə]量筒sliding scale['slaɪdɪŋ] [skeɪl]计算尺、按比例增减mass[mæs]团、块、堆Pascal ['pæskl]帕斯卡Action-reaction forces['ækʃən] [rɪ'ækʃən]反作用力resistance[rɪ'zɪstəns]阻力、电阻upthrust[ʌp'θrʌst]向上推electrostatic[ɪ,lektrəʊ'stætɪk]静电的unbalance['ʌn'bæləns]{力}失衡shape[ʃeip]形状、模型elastic[ɪ'læstɪk]松紧带、橡皮圈resilient[ri'ziliənt]弹回的moment['məʊm(ə)nt]转矩、动量、时刻equilibrium[,ikwɪ'lɪbrɪəm]平衡、均势sliding friction ['frɪkʃən]滑动摩擦slope[sləʊp]斜率简谐运动simple harmonic motion[hɑː'mɒnɪk] ['məʊʃ(ə)n]static friction ['stætɪk]静摩擦Thermal energy['θɜːm(ə)l] ['enədʒɪ]热能horizontally [,hɑrə'zɑntli]水平地、横地lamina['læmɪnə]薄板、薄层、叶片conduction[kən'dʌkʃ(ə)n]{生理}传导convection[kən'vekʃ(ə)n]对流radiation[reɪdɪ'eɪʃ(ə)n]辐射、发光、发射物insulator ['ɪnsjʊleɪtə]绝缘体electromagnetic [ɪ,lektrə(ʊ)mæg'netɪk]电磁的invar[ɪn'vɑr]不胀钢brass[brɑːs]黄铜、铜管乐器calibrate['kælibreit]校准、使标准化latent heat of vaporization['leɪt(ə)nt] [,vepərɪ'zeʃən]汽化潜能knob[nɒb]（门、抽屉的）球形把手thermostat['θɜːməstæt]恒温（调节）器mercury['mɝkjəri]水星、水银junction ['dʒʌŋkʃən]联结点、枢纽thermocouple['θɜːməʊkʌp(ə)l]热电偶thermistor[θɜː'mɪstə]电热调节器insulation [ɪnsjʊ'leɪʃ(ə)n]隔离、隔绝solidification[sə,lɪdəfə'keʃən]凝固latent heat of fusion ['fjʊʒən]熔解潜热boiling['bɔɪlɪŋ]沸腾的、激昂的manganate['mæŋgəneɪt]锰酸盐electromagnetic spectrum [ɪ,lektrə(ʊ)mæg'netɪk] ['spektrəm]电磁波频谱stirrer shaft['stɜːrə][ʃæft]搅拌器轴Carnot efficiency[ɪ'fɪʃənsi]卡诺循环Specific heat[spɪ'sɪfɪk]比热Cohesive force[kəʊ'hiːsɪv]内聚力Thermal equilibrium[,ikwɪ'lɪbrɪəm]热平衡Convection[kən'vekʃ(ə)n]对流传热Thermal expansion [ɪk'spænʃən]热膨胀Boiling point[pɔɪnt]沸点GCSE物理词汇。
引力波通达信 原理
引力波通达信原理Gravitational waves are ripples in spacetime that are caused by some of the most violent and energetic processes in the universe. These waves were first predicted by Albert Einstein in 1916 as part of his theory of general relativity. 引力波是时空中的涟漪，由宇宙中一些最激烈和富有活力的过程引起。
这些波首次由爱因斯坦在1916年预测，作为他的广义相对论理论的一部分。
One of the most exciting aspects of gravitational waves is that they allow us to observe phenomena in the universe that are otherwise invisible. These waves provide a new way for scientists to study black holes, neutron stars, and other exotic objects in space. 引力波最令人兴奋的一个方面是，它们使我们能够观测宇宙中否则看不见的现象。
这些波为科学家提供了一种新的研究黑洞、中子星和其他外星空间中的奇异物体的方法。
The detection of gravitational waves was one of the most significant scientific achievements of the 21st century. The first direct detection of these waves was made in 2015 by the Laser Interferometer Gravitational-Wave Observatory (LIGO) and was a monumentalmoment for astrophysics. 引力波的探测是21世纪最重大的科学成就之一。
怀疑与坚持从引力波的发现谈起作文
怀疑与坚持从引力波的发现谈起作文英文回答：The discovery of gravitational waves was a groundbreaking scientific achievement that has sparked both skepticism and persistence in the scientific community. Gravitational waves were first predicted by Albert Einstein in his theory of general relativity over a century ago, but it was not until 2015 that they were directly observed for the first time.The skepticism surrounding the discovery ofgravitational waves primarily stems from the fact that they are incredibly faint and difficult to detect. Gravitational waves are ripples in the fabric of spacetime caused by the acceleration of massive objects, such as black holes or neutron stars. These waves propagate through the universe, carrying information about the objects that created them. However, the effects of gravitational waves on spacetimeare minuscule, making their detection extremely challenging.Despite the skepticism, scientists persisted in their search for gravitational waves using advanced technology and innovative techniques. The Laser Interferometer Gravitational-Wave Observatory (LIGO) played a crucial role in the discovery. LIGO consists of two identical detectors located in different parts of the United States. Each detector consists of two perpendicular arms with mirrors at the ends. When a gravitational wave passes through the detectors, it causes the arms to stretch and compress, altering the path of laser beams that travel through them. By precisely measuring the changes in the laser beams, scientists can detect the presence of gravitational waves.The persistence of scientists paid off when, on September 14, 2015, LIGO detected the first-ever gravitational wave signal. This signal was generated by the merger of two black holes located over a billion light-years away. The detection of gravitational waves provided direct evidence for the existence of black holes and confirmed Einstein's theory of general relativity.中文回答：引力波的发现是一项具有突破性意义的科学成就，引起了科学界的怀疑和坚持。
2023年3月英语四级真题及参考答案
2023年3月英语四级真题及参考答案第一部分：听力Section A1. A) She won't attend the meeting.B) She has alreadyone the homework.C) She will remind the man of the meeting.D) She can't find the homework.2. A) The woman is not available at the moment.B) The man should speak loudly to the woman.C) The woman is not very interested in the talk.D) The man should reschedule the appointment.3. A) The man will study English in Australia.B) The woman has traveled to Australia herself.C) The man needs visa assistance for his trip.D) The woman can help him with the application.4. A) She will have a different timetable next term.B) She is still uncertain about her major.C) She needs advice on choosing courses.D) She enjoys the professors' lectures.5. A) Buy a ticket online.B) Get a discount from the college.C) Arrive on time for the concert.D) Join the fans club for the singer.Section B6. A) They used to be classmates in college.B) They joined a running club together recently.C) They met each other at a football match.D) They are discussing a sports event.7. A) She enjoys cooking for her friends.B) She has been on a diet for a while.C) She needs to prepare for a party.D) She likes to try different recipes.8. A) They are admiring a house.B) They are planning a renovation project.C) They are discussing a property investment.D) They are talking about their job opportunities.9. A) She is writing a report on environmental issues.B) She is doing a research on fossil fuels.C) She is taking a course on climate change.D) She is following the updates on global warming.10. A) They are running a charity organization.B) They are donating to a local food bank.C) They are discussing a social welfare program.D) They are organizing a volunteer event.第二部分：阅读Passage One11. B) Internet usage accelerates cultural change.12. D) Technology helps promote cultural diversity.13. C) The World Wide Web enables globalization.14. A) Online shoppers can have an enjoyable time.15. B) Internet retailers are renowned for low-quality products.Passage Two16. C) The formation and evolution of the universe.17. A) The discovery of gravitational waves.18. D) The emission of radio signals from space.19. B) The detection of an unusual pattern of movement.20. A) The image is unlikely to be captured by a ground-based telescope.Passage Three21. B) Respond to changing management trends.22. D) Solve problems encountered in their daily work.23. C) Learn to work in a competitive environment.24. A) Identifying employees' potential.25. B) Personal experiences of famous business leaders.第三部分：写作Part One注意：此题按照新议题写作要求，首段无需写作，不计入总词数。
新概念第四册Lesson40~42课文翻译及学习笔记
【导语】新概念英语作为家喻户晓的经典之作，它有着全新的教学理念，有趣的课⽂内容及其全⾯的技能训练，为⼴⼤的英语学习者提供帮助！如果你也想学好英语，⼜怎能错过新概念英语？下⾯为您提供了相关内容，希望对您有所帮助！新概念第四册Lesson40课⽂翻译及学习笔记 【课⽂】 First listen and then answer the following question. 听录⾳，然后回答以下问题。
What false impression does an ocean wave convey to the observer? Waves are the children of the struggle between ocean and atmosphere, the ongoing signatures of infinity. Rays from the sun excite and energize the atmosphere of the earth, awakening it to flow, to movement, to rhythm, to life. The wind then speaks the message of the sun to the sea and the sea transmits it on through waves -- an ancient, exquisite, powerful message. These ocean waves are among the earth's most complicated natural phenomena. The basic features include a crest (the highest point of the wave), a trough (the lowest point), a height (the vertical distance from the trough to the crest), a wave length (the horizontal distance between two wave crests), and a period (which is the time it takes a wave crest to travel one wave length). Although an ocean wave gives the impression of a wall of water moving in your direction, in actuality waves move through the water leaving the water about where it was. If the water was moving with the wave, the ocean and everything on it would be racing in to the shore with obviously catastrophic results. An ocean wave passing through deep water causes a particle on the surface to move in a roughly circular orbit, drawing the particle first towards the advancing wave, then up into the wave, then forward with it and then -- as the wave leaves the particles behind -- back to its starting point again. From both maturity to death, a wave is subject to the same laws as any other 'living' thing. For a time it assumes a miraculous individuality that, in the end, is reabsorbed into the great ocean of life. The undulating waves of the open sea are generated by three natural causes: wind, earth movements or tremors, and the gravitational pull of the moon and the sun. Once waves have been generated, gravity is the force that drives them in a continual attempt to restore the ocean surface to a flat plain. from World Magazine (BBC Enterprises) 【New words and expressions ⽣词和短语】 signature n. 签名，标记 infinity n. ⽆穷 ray n. 光线 energize v. 给与...能量 rhythm n. 节奏 transmit v. 传送 exquisite adj. ⾼雅的 phenomena n. 现象 crest n. 浪峰 trough n. 波⾕ vertical adj. 垂直的 horizontal adj. ⽔平的 actuality n. 现实 catastrophic adj. ⼤灾难的 particle n. 微粒 maturity n. 成熟 undulate v. 波动，形成波浪 tremor n. 震颤 gravitational adj. 地⼼吸⼒的 【课⽂注释】 1.transmit vt. ①传达 例句：Gypsies frequently transmit recipes orally within the family. 吉普赛⼈经常以⼝头形式把秘⽅世代相传。
跟重力有关的技能名词解释
跟重力有关的技能名词解释导言：在物理学领域中，重力是一个至关重要的概念，它是地球或其他天体引起物体相互吸引的力。
在日常生活中，我们通常对重力的概念并不陌生，但是在某些领域，如空间技术、工程学以及运动学等，重力的影响可以被进一步探讨和利用。
本文将解释一些跟重力有关的技能名词，旨在帮助读者更全面地理解和运用这些概念。
一、轨道（Orbit）轨道是指物体绕天体运动的路径，是由两种力共同作用下的结果：重力和离心力。
当物体以足够高的速度沿着地球表面平行于地面发射时，物体就会进入轨道。
在轨道上，物体将不断地受到重力的引力，同时也会经历向心力，使得物体保持稳定的椭圆轨道。
二、零重力（Zero Gravity）零重力是指在某些特定的条件下，物体没有受到重力的影响，给人一种体验到无重力的错觉。
实际上，零重力并不是真正的没有重力存在，而是指物体在自由下落或者处于离心力与重力平衡的情况下，感受到的重力减小至接近于零。
这种状态通常在宇宙飞船、减速下沉的电梯以及高架桥边的跳楼体验中会出现。
三、空间行走（Spacewalk）空间行走是指宇航员在航天器外进行活动和维修任务。
在太空中，物体不再受到地球上的重力束缚，因此宇航员在进行空间行走时需要依靠太空服提供的推力和稳定性。
重力的缺失使得空间行走变得富有挑战性，宇航员必须经过专门的训练来适应和应对这种新环境。
四、加速度（Acceleration）加速度是指物体速度变化的快慢程度的度量。
在受到重力的作用下，自由下落的物体将不断地加速。
根据万有引力定律，重力加速度在地球表面约为9.8米/秒²，这意味着当一个物体自由下落时，其速度每秒增加9.8米。
加速度的了解对于为太空飞行、火箭发射以及构建高速交通系统等项目设计提供了重要依据。
五、重力波（Gravitational Waves）重力波是指由质量分布不均引起的扰动，可以通过空间中传播的类似水波的形式将能量传递出去。
当两个极其密集的物体，例如黑洞或中子星碰撞产生震荡时，将会产生极强的重力波。
高中物理术语
高中物理术语测量-measure,温度-temperature误差-uncertainty,气压-pressure熔点-meltingpoint,沸点-boilingpoint实验-experiment,气体-gas液体-liquid,固体-solid质子-proton,中子-neutron电子-electron,中微子-neutrino质量-mass,密度-density压力-pressure,力-force摩擦力-friction,重力-gravitationalforce潮汐力-tidalforce,电场-electricfield磁场-magneticfield,核裂变-nuclearfission核聚变-nuclearfusion,电源-power电阻-resistance,二极管-diode三极管-transistor,电容-capacitor电压-voltage,电流-current保险丝-fuse,电压表-voltmeter电流表-ammeter,并联-parallel串联-serie,开关-switch导体-conductor,绝缘体-insulator 晶闸管-thyratron,变压器-transformer位移-displacement,速度-velocity加速度-acceleration,系数-coefficient离子-ion,分子-molecule原子-atom,氢–hydrogen force力motion运动unit单位SIUnit国际标准单位vector向量scalar数量与向量相对,就是数displacement位移distance距离velocity速度instantaneousvelocity瞬时速度averagevelocity平均速度acceleration加速度instantaneousacceleration 瞬时加速度averageacceleration平均加速度netforce合力staticfiction静摩擦力kineticfiction滑动摩擦力coefficientoffiction摩擦系数gravitationalforce重力mass质量Newton’sLaw牛顿运动/力学定律Galileo伽利略energy能work功power功率gravitationalpotentialenergy重力势能kineticenergy动能thermalenergy热能wave波mechanicalwave机械波longitudinalwave纵波transversewave横波period周期frequency频率amplitude振幅phase相位wavelength波长superposition波的叠加constructiveinterference相长干涉destructiveinterference相消干涉standingwaves驻波resonance共振media媒介vibrate振动soundwave声波Dopplereffect多普勒效应reflection反射refraction折射indexofrefraction折射率totalinternalreflection全反射criticalangle临界角focalpoint焦点image像lenses透镜converginglenses会聚透镜diverginglenses发散透镜electricity电magnetism磁electriccharge电荷electriccurrent电流electricpotential电势electricfield电场uniformmagneticfield匀强磁场electromagneticinduction电磁感应kilowatt-hour千瓦时electriccircuit电路conductor导体solenoid螺线管Lenz’sLaw楞次定律directcurrent直流alternatingcurrent交流inertial/non-inertialframesofreference惯性/非惯性参考系inclinedplane斜面projectile抛射circularmotion圆周运动momentum动量impulse冲量elasticpotentialenergy弹性势能elastic/inelasticcollision弹性/非弹性碰撞open/closedsystem开放/封闭系统simpleharmonicmotion简谐运动mechanicenergy机械能conservationofmomentum/energy动量/能量守恒Coulomb’sLaw库仑定律dispersion色散polarization偏振光spectrum波谱Young’sdoubleslit杨氏双缝radioactivity放射quantumtheory量子论photoelectriceffect光电效应matterwaves 物质波德布罗意波Bohrmodel 波尔模型quantummechanics量子力学special/generaltheoryofrelativity狭义／广义相对论elementaryparticles基本粒子quark夸克lepton轻子。
用于引力波关键技术验证的近地低成本商业卫星设计
３．１ 轨道分析及设计 根据引力波探测目标，最佳轨道应为远离地
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我国在空间引力波探测领域起步较晚，２０１６ 年，经过多年的酝酿、调研和积累，中国科学院正 式提出 并 启 动 了 我 国 空 间 引 力 波 探 测 “太 极 计 划”［５］。中山 大 学 也 提 出 了 天 琴 计 划，然 而 天 琴 轨道为绕地轨道，臂长约为十七万公里，只能探测 频段偏高的波源，且难以避免地月系统对其稳定 性的影响以及太阳保持热辐射稳定性的影响［１０］。
Ａｂｓｔｒａｃｔ：Ｄｅｔｅｃｔｉｎｇｇｒａｖｉｔａｔｉｏｎａｌｗａｖｅｓｏｎｇｒｏｕｎｄｗａｓｌｉｍｉｔｅｄｂｙｔｈｅｎｏｉｓｅｓｓｕｃｈａｓｓｕｒｆａｃｅｖｉｂｒａｔｉｏｎ，ｇｒａｖｉｔｙ ｇｒａｄｉｅｎｔａｎｄｔｈｅｔｅｓｔｓｃａｌｅ．Ｔｈｅｄｅｔｅｃｔｉｏｎｆｒｅｑｕｅｎｃｙｂａｎｄｉｓｌｉｍｉｔｅｄｔｏｍｏｒｅｔｈａｎ１０Ｈｚｗｈｉｌｅｔｈｅｄｅｔｅｃｔｉｏｎｆｒｅ ｑｕｅｎｃｙｂａｎｄｉｓｍａｉｎｌｙｉｎｔｈｅｍｉｄｄｌｅａｎｄｌｏｗｆｒｅｑｕｅｎｃｙｂａｎｄ（０１ｍＨｚ～１Ｈｚ）ｆｏｒｗａｖｅｓｏｕｒｃｅｓｗｉｔｈｌａｒｇｅｒ ｆｅａｔｕｒｅｑｕａｌｉｔｙａｎｄｓｃａｌｅ．Ｓｏｉｎｏｒｄｅｒｔｏａｖｏｉｄｇｒｏｕｎｄｉｎｔｅｒｆｅｒｅｎｃｅ，ｄｅｔｅｃｔｉｏｎｆｒｏｍｓｐａｃｅｉｓｉｎｅｖｉｔａｂｌｙｎｅｃｅｓｓａ ｒｙ．Ａｓｇｒａｖｉｔａｔｉｏｎａｌｗａｖｅｓｉｇｎａｌｓａｒｅｅｘｔｒｅｍｅｌｙｗｅａｋａｎｄｔｈｅｉｒｒｅｑｕｉｒｅｄｄｅｔｅｃｔｉｏｎａｃｃｕｒａｃｙｉｓｅｘｔｒｅｍｅｌｙｈｉｇｈ， ｓｐａｃｅｇｒａｖｉｔａｔｉｏｎａｌｗａｖｅｄｅｔｅｃｔｉｏｎｐｒｏｊｅｃｔｓｒｅｐｒｅｓｅｎｔｅｄｂｙＬＩＳＡｗａｓｐｒｏｐｏｓｅｄｂｙＥＳＡａｎｄＴａｉｊｉｗａｓｐｒｏｐｏｓｅｄ ｂｙｔｈｅＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃｅｓ．Ｈｏｗｅｖｅｒ，ｂｏｔｈｄｏｍｅｓｔｉｃａｎｄｆｏｒｅｉｇｎｐｒｏｐｏｓｅｄｐｒｏｊｅｃｔｓｈａｄｅｘｔｒｅｍｅｌｙ
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v12
3kTc . 12
For a core temperature of Tc 10 7 K , the velocity of the particles is of the order of
8 10 5 m / s . For a star of density 200 g / cc 2 10 5 kg / m 3 , the numbeting in these values we get the power of thermal gravitational waves emitted as,
10 9 Watt at a frequency of 1017 Hz . E
2
The flux of thermal gravitational waves from the sun, received at earth is of the order of half a watt. 2. Thermal gravitational waves from compact stars In the case of white dwarfs, the number density is of the order of n1 n2 10 37 m 3 , and the velocity corresponding to the white dwarf temperature of Tc 10 8 K , is of the order of 2 10 6 m / s . The volume of the white dwarf is of the order of 4 1018 m 3 and the frequency corresponding to the temperature Tc 10 8 K is And for a white dwarf,
10 22 Watt at the frequency of 10 21 Hz . the order of, E
3
We assume collisions of neutrons described by hard sphere fermion model with scattering length of the order of 5 1016 m . We restrict to S-wave scattering since the de Broglie wavelength is large compared to this length. The integrated power density is given by: 8G Pg 5 3 2 n 5c
1
Christ Junior College, Bangalore
1
Due to Coulomb collisions in the core of the stars, thermal gravitational waves can be generated. These thermal gravitational waves can arise in white dwarfs and neutron stars due to the fermion collisions in the dense degenerate Fermi gas. Such high frequency thermal gravitational waves are also produced during the collisions in a gamma ray burst or in the jets of a rotating black hole. 1. Thermal gravitational waves from stellar cores
32G 2 d 5 E sin 2 V 5 12 n1n 2 v12 d 5c
…(1)
kTc 1017 Hz is the frequency h
Where, V is the volume of the stellar core and
corresponding to the core temperature of the star of Tc 10 7 K . The velocity of the particles at the core of temperature Tc is given by:
thermal gravitational radiation, which in the case of hot
neutron stars can be high. Also white dwarfs and main-sequence stars can generate such radiation from plasma-Coulomb collisions. Again gamma ray bursts and relativistic jets could also be sources of such radiation. Terminal stages of evaporating black holes could also generate high frequency gravitational radiation. A comparative study is made of the thermal gravitational wave emission from all of the above sources, and the background flux is estimated. The earliest phases of the universe close to the Planck scale would also leave remnant thermal gravitational waves. The integrated thermal gravitational flux as the universe expands is also estimated and compared with that from all the discrete sources discussed above. Possible schemes to detect such sources of high frequency thermal gravitational radiation are discussed and the physical principles involved are elaborated.
given as: n1 n2
V 10 27 m 3 .
mP
10 32 m 3 . The volume of the star is of the order of
And for a main sequence star
[3]
d e4 2 , sin 5 10 28 m 2 2 2 4 d 8 0 12 v12
d 12 d
If n1 , n2 are the number densities of gas particles undergoing collision with a
differential scattering cross-section, with relative velocity v12 and reduced mass 12 , then the power per unit volume per unit frequency interval is given by the quadrupole formula as: [1, 2]
TD . Even for a newly formed hottest neutron star Tc 5 1010 K TD 1014 K . [4]
3. Thermal gravitational waves from gamma ray bursts Gamma-ray bursts (GRBs) are the most luminous physical phenomena in the universe known to the field of astronomy. They consist of flashes of gamma rays that last from seconds to hours, the longer ones being followed by several days of X-ray afterglow. [5,6] Similar to the stars, in GRBs also, Coulomb collisions can result in the emission of high frequency gravitational waves. The power of the thermal gravitational waves is given by the same expression as that for the stars, but the bulk properties will be altered by factors of , due to the relativistic velocities encountered in GRBs.
kTc 1018 Hz . h
d e4 2 sin 10 29 m 2 d 2 2 4 8 0 12 v12
…(3a)
The power of thermal gravitational waves emitted by the white dwarf works out to be of
Thermal gravitational waves C Sivaram and Kenath Arun1 Indian Institute of Astrophysics, Bangalore