共查询到20条相似文献,搜索用时 62 毫秒
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液氮间接冷却晶体单色器第一晶体热变形模拟计算 总被引:4,自引:0,他引:4
针对上海光源U27波荡器光源, 用ANSYS有限元软件对晶体单色器第一晶体液氮间接冷却进行数值模拟, 给出晶体表面倾斜误差与热负载、冷却条件和布喇格角范围等因素的关系, 为晶体单色器的设计与制造提供热缓释依据. 晶体距光源中心24m时最大垂直入射功率密度约为60W/mm2, 在布喇格角调节范围小于30°时, 晶体厚度大于30mm, 晶体吸收总功率上限可到240W, 即可满足SSRF储存环电子束流升级到400mA的需求, 采用正常液氮(78K)冷却晶体, 晶体表面热变形倾斜误差可控制在3arcsec以下. 相似文献
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流固耦合管路系统广泛应用于各种装备中,通常用来传递物质和能量或者动量.由于流固耦合效应,管壁在流体作用下易产生强烈的振动与噪声,对装备安全性、隐蔽性产生严重影响,甚至造成严重破坏.流固耦合管路振动抑制需求迫切,意义重大.声子晶体可以利用其带隙特性抑制特定频率范围内弹性波的传播,在减振降噪领域具有广泛的应用前景.本文基于声子晶体理论,研究了流固耦合条件下的布拉格声子晶体管路冲击振动传递特性.将传递矩阵法和有限元法相结合,计算了能带结构与带隙特性,重点考虑了流固耦合效应下,不同冲击激励条件下声子晶体管路振动特性,分析了流固耦合对声子晶体管路振动传递特性的影响.研究结果为流固耦合条件下管路系统的振动控制提供了技术参考. 相似文献
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本文通过数值模拟的方法同时考虑了耦合传热和冷却流通道流动对气膜冷却的影响.计算结果表明,在考虑耦合传热的情况下,冷却流通道流动的影响仍然存在,但随着壁面导热系数的增大,这种影响减弱;同时在考虑耦合传热的情况下,受保护壁面温度场分布更加均匀,冷却效果更好.计算结果还表明吹风比为0.5时的冷却效果优于吹风比为1.0的情况. 相似文献
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探路者号火星探测器气动热和传热耦合分析 总被引:1,自引:0,他引:1
本文建立高超声速气动热和结构传热的松耦合计算方法,以探路者号火星探测器为研究对象,开展了探测器高超声速气动热和结构传热的耦合计算研究,分析了探测器进入条件下某轨道点上气动加热和结构传热机理。耦合计算表明,随着时间的推进,表面结构温度逐渐升高,壁面热流相对降低,表面趋向辐射平衡温度。因热防护系统结构传热时间尺度长于飞行器进入过程总时间,探测器进入的真实过程滞后于辐射平衡过程。耦合研究表明,使用耦合计算方法能较好地再现真实的气动加热和结构传热过程。 相似文献
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硅晶体与无氧铜界面之间的接触热阻影响第三代同步辐射光源中承受高热负荷的硅晶体单色器冷却结构性能优化设计。实际测量固体界面处接触热阻时,温度传感器安装方式和加热功率均影响实验准确性。文中利用数值模拟方法从这两方面对接触热阻计算偏差进行分析。结果表明,焊接或粘贴方式安装温度传感器使测温更加接近真实情况,并且测量接触热阻越小,加热功率可调范围越小,对测量仪器精度要求越高,进而对实际测量方法的选择有现实指导意义。 相似文献
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首次报道四方相FeiKTN晶体的二波耦合性质.测得晶体的二波耦合增益系数和衍射效率分别为7.3cm~(-1)和42%,响应时间为2.8sec.文中还分析了主要载流子的符号并计算了其它参数. 相似文献
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The results of high-heat-load tests of indirectly cryogenically cooled silicon monochromators are presented. The measurements show that, provided that the total power absorbed by the crystal is less than approximately 150 W, indirect cryogenically cooled silicon monochromators will perform well, with thermal-induced slope errors of less than 2 arcsec. At the Advanced Photon Source, this corresponds to the undulator closed-gap (11 mm) condition at 100 mA with white-beam slit sizes slightly larger than the full width at half-maximum of the radiation central cones. The dependence of the slope errors on the thermomechanical properties of silicon are discussed and clearly demonstrated. 相似文献
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《中国物理 B》2021,30(7):73702-073702
A two-ion pair in a linear Paul trap is extensively used in the research of the simplest quantum-logic system; however,there are few quantitative and comprehensive studies on the motional mode coupling of two-ion systems yet. This study proposes a method to investigate the motional mode coupling of sympathetically cooled two-ion crystals by quantifying three-dimensional(3 D) secular spectra of trapped ions using molecular dynamics simulations. The 3 D resonance peaks of the ~(40)Ca~+ – ~(27)Al~+ pair obtained by using this method were in good agreement with the 3 D in-and out-of-phase modes predicted by the mode coupling theory for two ions in equilibrium and the frequency matching errors were lower than 2%.The obtained and predicted amplitudes of these modes were also qualitatively similar. It was observed that the strength of the sympathetic interaction of the ~(40)Ca~+ – ~(27)Al~+ pair was primarily determined by its axial in-phase coupling. In addition,the frequencies and amplitudes of the ion pair's resonance modes(in all dimensions) were sensitive to the relative masses of the ion pair, and a decrease in the mass mismatch enhanced the sympathetic cooling rates. The sympathetic interactions of the ~(40)Ca~+ – ~(27)Al~+ pair were slightly weaker than those of the ~(24)Mg~+– ~(27)Al~+ pair, but significantly stronger than those of ~9Be~+ – ~(27)Al~+ . However, the Doppler cooling limit temperature of ~(40)Ca~+ is comparable to that of ~9Be~+ but lower than approximately half of that of ~(24)Mg~+. Furthermore, laser cooling systems for ~(40)Ca~+ are more reliable than those for ~(24)Mg~+and ~9Be~+ . Therefore, ~(40)Ca~+ is probably the best laser-cooled ion for sympathetic cooling and quantum-logic operations of ~(27)Al~+ and has particularly more notable comprehensive advantages in the development of high reliability, compact, and transportable ~(27)Al~+ optical clocks. This methodology may be extended to multi-ion systems, and it will greatly aid efforts to control the dynamic behaviors of sympathetic cooling as well as the development of low-heating-rate quantum logic clocks. 相似文献
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The effect of angular vibrations of the crystals in cryogenically cooled monochromators on the beam performance has been studied theoretically and experimentally. A simple relation between amplitude of the vibrations and size of the focused beam is developed. It is shown that the double‐crystal monochromator vibrations affect not only the image size but also the image position along the optical axis. Several methods to measure vibrations with the X‐ray beam are explained and analyzed. The methods have been applied to systematically study angular crystal vibrations at monochromators installed at the PETRA III light source. Characteristic values of the amplitudes of angular vibrations for different monochromators are presented. 相似文献
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利用软件Maxwell对中国聚变工程实验堆(CFETR)高场侧的水冷陶瓷增殖(WCCB)包层进行电磁分析,得到了包层在等离子体电流线性36ms衰减工况下产生的电磁载荷.采用载荷传递耦合法,结合软件ANSYS可得包层中产生的形变位移和等效应力.分析结果表明,WCCB包层中产生的最大等效应力符合设计要求,且形变位移均在许用... 相似文献
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A high resolution fully automated photoacoustic spectrometer (PAS) of the gas-microphone type is used in the photon energy region 0.8–1.6 eV to analyze the optical properties of silicon single crystals at different frequencies between 25 and 312 Hz. At modulating frequencies at which the sample thickness approaches its thermal diffusion length, the results obtained of untreated specimens using different PA cells reveal the presence of several peaks in the absorption tail, some of which are independent of the photon energy. The magnitude of these peaks is seen to be stronger than that of the maximum of the fundamental edge of silicon, thus making it indistinct. At lower modulating frequencies at which the sample thickness is far less than its thermal diffusion length and using a highly reflecting backing material, multiple reflections of the light beam within the sample interfaces are seen to enhance the PA amplitude signal sensitivity response as predicted theoretically. The effect of etching silicon samples in a diluted solution of hydrofluoric acid (5%) on photoacoustic spectra has been investigated. It is observed that this process removes all spurious features in the spectra originating from the surface contaminants making the fundamental absorption edge clearly visible and leaving only one distinct peak at hν=0.9 eV. Transmission-photoacoustic (T-PAS) has also been used to study silicon single crystals. In the light of recent literature a comparison is carried out between the results obtained using the two techniques in determining the absorption coefficient and the gap energy. 相似文献
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《Infrared Physics & Technology》2007,49(3):175-180
The spectral responsivity of cryogenically cooled HgCdTe detectors was observed to drift slowly with time. The magnitude of the drift was shown to be strongly dependent on wavelength. The origin of the drift was investigated and was shown to arise due to a thin film of water ice depositing on the active area of the cold detector. The presence of the ice film (which is a dielectric film) interacts with the detector structure thus altering its absorbance characteristics and gives rise to the observed drifts. The drifts were temporarily eliminated by evacuating the detector dewars while baking them at 50 °C for about 48 h. This work demonstrates that HgCdTe infrared detectors should be evacuated and baked at least annually and in some cases (depending on the quality of the dewar and the measurement uncertainty required) more frequently. These observations are particularly relevant to HgCdTe detectors mounted in dewars which utilise rubber O-rings, as the ingress of moisture was found to be particularly serious in this type of dewar. This paper also identified other sources of drift present in the output of cryogenically cooled photoconductive HgCdTe detectors whose origins are currently not understood. 相似文献
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Lin C Chen C Sharkawy A Schneider GJ Venkataraman S Prather DW 《Optics letters》2005,30(11):1330-1332
We present a promising coupling device, namely, a terahertz (THz) planar photonic crystal (PhC) lens based on the effective refractive-index contrast between the PhC and the surrounding unpatterned area. Three-dimensional finite-difference time-domain calculations show a 90% power transfer from a 100-microm silicon waveguide to a 10-microm waveguide, and 45% coupling efficiency is confirmed experimentally. These results demonstrate the utility of the PhC lens as an effective approach to coupling into PhC THz circuits. 相似文献