Review of publications concerning service systems noise in buildings

The results of a review of recently published literature concerned with service systems noise in buildings are given here in an attempt to highlight those areas of research which particularly need further investigation. The wide nature of the subject has precluded the normal review paper ‘discussion’ approach, and hence the information is presented in tabular form.The reference list contains those papers which have been found relevant in the course of work on a project on systems noise. Obviously not all quoted papers were of direct use to the work, but they are included to increase the usefulness of this paper.     

用于住宅建筑的太阳能吸收式空调性能分析

夏季太阳能辐射强度与空调负荷有很好的一致性,这使得太阳能辅助空调具有独特的优点。根据郑州地区夏季太阳辐射和空调负荷特点,针对某一太阳能辅助吸收式空调系统进行了理论分析,该系统供冷对象为200m2别墅,采用60m2平板式太阳能集热器和一个带有辅助加热装置的集热水箱作为热源。在发生器温度为70—100℃,蒸发温度5—15℃的范围内计算了系统性能系数和太阳能利用率。计算结果表明,在5—9月份,太阳能可以提供建筑冷负荷的76—122%。     

Total internal reflection diffraction grating in conical mounting

The main conditions and parameters for obtaining surface relief total internal reflection diffraction gratings in conical mounting are presented. Calculated and experimental investigations reveal that there are ranges of grating periods, incidence angles, diffraction angles and gratings depths for which such gratings could be obtained, both for TE and TM polarizations. With optimized grating parameters the diffraction efficiency of the total internal reflection diffraction gratings can be greater than 90%.     

Resilient silk captures prey in black widow cobwebs

The gumfoot thread of a black widow (Latrodectus hesperus) spider’s cob web is a spring-loaded trap that yanks walking insects into the web. Since spider silks are known as energy dissipating materials, we investigated this trap to find out where the energy is stored. Using previously measured material properties, we modeled the gumfoot thread as a damped harmonic oscillator and compared it to high speed video analysis of prey capture. These measurements show that the gumfoot thread is plastically deformed during prey capture and cannot be the site of energy storage. We then measured the material properties of scaffolding silk that makes up the upper portion of the cob web. Scaffolding silk is highly resilient (90%) at strains less than 3%. This energy storage is sufficient to drive the oscillations seen in prey capture and is consistent with the measured kinematics. This study is the first demonstration of energy-storage as a primary biological function for spider silk. PACS 87.15.La; 81.40.Jj; 81.05.Lg     

Excitation of eigenmodes at gyroelectromagnetic gratings in conical mounting

We study the diffraction of electromagnetic waves at periodically corrugated isotropic–gyroelectromagnetic surfaces, in the index-matching situation, when the plane of incidence forms an arbitrary angle with the main section of the grating (“conical mounting”). It is shown that, under these conditions, eigenmodes can be excited at certain angles of incidence, which can be calculated. We analyze the variation of the position of the anomalies when the orientations of the plane of incidence and of the optic axis are varied. We also show the dependence of the maximum reflected power as a function of the groove height-to-period ratio.     

大口径反射镜低应力夹持技术

高功率固体激光装置对大口径反射镜附加波前畸变和姿态稳定提出了苛刻的要求,在确保姿态稳定性的同时,要求低应力夹持使附加波前畸变峰谷值（PV值）＜λ/3, 波长λ＝633 nm。提出了一种正面三点支撑结合侧面八点限位的大口径反射镜夹持技术,对该夹持结构下引起的附加波前畸变进行了仿真和实验研究,并对反射镜姿态稳定性进行了不同工况下的实验模拟。结果表明,该夹持方式引入的附加波前畸变PV值约为23.6 nm,振动、晃动、翻转不同工况下反射镜指向变化PV值小于50 μrad,附加波前畸变和姿态稳定性均满足高功率激光装置的要求。     

An improved loopless mounting method for cryocrystallography

Based on a recent loopless mounting method, a simplified loopless and bufferless crystal mounting method is developed for macromolecular crystallography. This simplified crystal mounting system is composed of the following components: a home-made glass capillary, a brass seat for holding the glass capillary, a flow regulator, and a vacuum pump for evacuation. Compared with the currently prevalent loop mounting method, this simplified method has almost the same mounting procedure and thus is compatible with the current automated crystal mounting system. The advantages of this method include higher signal-to-noise ratio, more accurate measurement, more rapid flash cooling, less x-ray absorption and thus less radiation damage to the crystal. This method can be extended to the flash-freeing of a crystal without or with soaking it in a lower concentration of cryoprotectant, thus it may be the best option for data collection in the absence of suitable cryoprotectant. Therefore, it is suggested that this mounting method should be further improved and extensively applied to cryocrystallographic experiments.     

New stigmatic mounting of holographiccylindrical diffraction grating

A new stigmatic mounting of a holographic cylindrical diffraction grating has been considered to be used in the field of X-ray and XUV regions. The conditions for zero astigmatism and sagittal coma have been obtained. Astigmatism per unit length has been plotted against wavelength using the design parameters which give zero astigmatism at least at one wavelength.     

Grating-coupled surface plasmon resonance in conical mounting with polarization modulation

A grating-coupled surface plasmon resonance (GCSPR) technique based on polarization modulation in conical mounting is presented. A metallic grating is azimuthally rotated to support double-surface plasmon polariton excitation and exploit the consequent sensitivity enhancement. Corresponding to the resonance polar angle, a polarization scan of incident light is performed, and reflectivity data are collected before and after functionalization with a dodecanethiol self-assembled monolayer. The output signal exhibits a harmonic dependence on polarization, and the phase term is used as a parameter for sensing. This technique offers the possibility of designing extremely compact, fast, and cheap high-resolution plasmonic sensors based on GCSPR.     

水平式光电望远镜静态指向误差的修正

为了提高水平式光电望远镜静态指向精度,对光电望远镜静态指向修正模型进行了理论分析和实验研究,建立了水平式望远镜指向模型。首先,介绍了球谐函数模型和水平式望远镜指向模型,并对水平式望远镜指向模型加以修改。然后,对全天区均匀分布的70颗Tycho-2恒星进行实际观测,获得水平式光电望远镜在L轴和B轴上的指向偏差,利用最小二乘法对该模型进行拟合,计算出水平式望远镜指向模型中各待定系数。最后,采用该指向模型对某型水平式望远镜进行了修正。实验结果表明:采用水平式望远镜指向模型进行修正后,望远镜设备总指向精度由修正前的152.10"提高到了4.76"。满足系统总体提出的精度要求,能够广泛地应用于科研和工程领域。     

A new crystal mounting method for macromolecular cryocrystallography

The fundamental advantage of soft-X-ray ARPES (SX-ARPES) with photon energies around 1 keV compared to the conventional vacuum-ultraviolet ARPES (VUV-ARPES) is an increase of the photoelectron escape depth. This enhances the bulk sensitivity of the ARPES experiment as well as enables access to buried systems such as interfaces, heterostructures, and impurities. This advantage combines with resolution in three-dimensional (3D) momentum k, which, on the other hand, degrades upon further increase of energy into the hard-X-ray range. The main challenge of SX-ARPES is the valence band (VB) photoemission cross-section decreasing by a few orders of magnitude compared to the VUV-ARPES energy range. This problem can only be overpowered with advanced synchrotron radiation instrumentation delivering high photon flux. In this article, after a recap of the main virtues and current challenges of SX-ARPES, we report on the recent instrumental progress at the Swiss Light Source (SLS), where a new SX-ARPES facility was installed at the Advanced Resonant Spectroscopies (ADRESS) beamline. The high photon flux above 10¹³ photons/s/0.01%BW delivered by this beamline, combined with the optimized endstation geometry, has allowed us to break through the cross-section problem and, furthermore, push the applications of SX-ARPES from bulk materials to extremely photon-hungry cases of buried systems. Complementing the recent review of the whole field of soft- and hard-X-ray ARPES published in this magazine [1 C.S. Fadley, Synchr. Rad. News 25, 26 (2012).[Taylor &; Francis Online] , [Google Scholar]], we here focus on the recent SX-ARPES applications emerging with the advanced instrumentation of the SLS.     

翻修贴片设备在ICCD光锥耦合中的应用

为了提高光锥耦合ICCD成像系统的成品率和成像质量,提出了一种将通用BGA翻修系统中的高精度贴片设备ERSA PL550A用于光锥和CCD耦合工艺的方法。利用光锥或光纤面板与CCD的耦合实例描述了这种技术方案的系统构成、操作流程和耦合精度,证明了它在简化耦合工艺、降低操作难度、控制耦合操作的重复性和提高生产效率方面具有良好的性能。对CCD玻璃窗的开启方法和光锥形状尺寸的二次修改也进行了简要说明。     

High Performance Fairness Algorithm for Resilient Packet Ring

Resilient Packet Ring (RPR) is MAN technology with two counter-rotating rings that multiple stations share the bandwidth. The stations on ring must negotiate the allowed rate that they can transmit fairness eligible traffic based on the total amount of uncommitted bandwidth. RPR draft employs distributed bandwidth control algorithm in order to assure global fairness. In this paper, we suggest a new fairness control algorithm termed Congestion Distributed Fairness Algorithm (CDFA) that exhibits better performance than RPR fairness algorithm. It attributes all stations on ring to have a regular transmission rate even though heavy congestion occurs in a station.     

舰船隔振装置技术及其进展

隔振装置是降低舰船机械噪声最重要的技术之一,目前已有大量文献对舰船隔振装置技术进行了研究,但系统、全面地论述其技术特点、应用和进展,尤其是我国在该领域进展的文献相当缺乏。针对已应用并取得成效的舰船隔振装置技术,首先概述了其发展历程,分析了单层隔振装置、双层隔振装置、浮筏双层隔振装置和气囊隔振装置的技术特点;然后介绍了近年来该领域的进展,包括智能气囊隔振装置、推进动力系统新型隔振装置、主被动混合隔振装置、推力轴承隔振装置等;最后对隔振装置技术的未来发展趋势进行了展望。通过系统地总结梳理,较完整地呈现了舰船隔振装置技术发展概况,可供舰船减振降噪研究和工程设计人员参考。     

Polarizing beam splitter of two-layer dielectric rectangular transmission gratings in Littrow mounting

We theoretically investigated the design of polarizing beam splitters (PBS) of two-layer dielectric rectangular transmission gratings in Littrow mounting. The PBS grating is aimed to separate TE and TM polarized waves into two different transmitted orders, i.e. the 0th and −1st orders. The polarization-dependent diffraction process is analyzed by using a simplified modal method. The mode reflection and transmission at the interface of the two layers are illustrated. Design equations are given based on the average mode indices of the even and odd modes inside the grating region, which are verified by using rigorous coupled wave analysis. Moreover, with simulated annealing algorithm, two kinds of two-layer PBS gratings are optimized for operation over the C-band (1520-1570 nm). Compared with the single-layer transmission PBS gratings, such two-layer scheme exhibits a great flexibility of design. The PBSs of two-layer dielectric transmission gratings should be useful for practical applications.     

弹性分组环网的分组延时性能研究

本文采用了M/G/1/K排队模型对Darwin标准草案中建议的弹性分组环网的分组传输延时进行了性能分析,结果表明不同优先级的业务等待延时不同,高优先级分组在网络中传输延时最低,中优先级分组的延时仅略低于低优先级分组,当网络规模增加时,这种差距逐渐减小甚至可以忽略;并且从理论上推导出网络最大吞吐量,这对于制定相关标准、设计和规划实用网络具有重要指导作用.     

Dynamic ground compliance in multistorey buildings

A study is presented of the changes in the characteristics of the natural modes of vibration for multistorey structures which are founded on flexible foundations. First a standard eigenvalue problem is formulated for the proportionally damped case. Then general relationships of changes in natural frequencies and mode shapes are derived for the linear vibration theory. By means of an example problem it is demonstrated, however, that only the first mode obeys the predicted changes of frequencies and mode shapes over a wide range of foundation stiffness. The higher modes are shown to deviate substantially from the linear behaviour. This deviation is ascribed to geometric changes in mode shapes.     

Visualization of leakage flow in buildings

Leakage flow around a window has been visualized with the aid of holographic interferometry. The experiments were performed during winter.