基于玻璃回流的TGV衬底制备

针对MEMS器件背面引线的需求,提出了一种基于玻璃通孔(TGV)加工方法的10.16cm(4inch)圆片衬底的制备工艺流程。首先深硅刻蚀导电硅片,然后将硅片和玻璃片阳极键合,随后将键合后的玻璃-硅圆片经高温加热,使玻璃填充至硅片中,再依次研磨抛光玻璃-硅圆片的正面玻璃和背面硅,直至硅与嵌入玻璃在同一平面,最后得到了厚度为258μm的4inch圆片衬底,其轮廓算术平均偏差、轮廓最大高度、微观不平度十点高度的平均值分别为13,71和49nm。此外,测得圆片中硅导通柱电阻率为0.023Ω·cm。

Technique of coal mining and gas extraction without coal pillar in multi-seam with low permeability

Aimed at the low mining efficiency in deep multi-seams because of high crustalstress,high gas content,low permeability,the compound 'three soft' roof and the trouble-somesafety situation encountered in deep level coal exploitation,proposed a new idea ofgob-side retaining without a coal-pillar and Y-style ventilation in the first-mined key pressure-relieved coal seam and a new method of coal mining and gas extraction.The followingwere discovered:the dynamic evolution law of the crannies in the roof is influenced bymining,the formative rule of 'the vertical cranny-abundant area' along the gob-side,thedistribution of air pressure field in the gob,and the flowing rule of pressure-relieved gas ina Y-style ventilation system.The study also established a theoretic basis for a new miningmethod of coal mining and gas extraction which is used to extract the pressure-relievedgas by roadway retaining boreholes instead of roadway boreholes.Studied and resolvedmany difficult key problems,such as,fast roadway retaining at the gob-side without a coalpillar,Y-style ventilation and extraction of pressure-relieved gas by roadway retainingboreholes,and so on.The study innovated and integrated a whole set of technical systemsfor coal and pressure relief gas extraction.The method of the pressure-relieved gasextraction by roadway retaining had been successfully applied in 6 typical working faces inthe Huainan and Huaibei mining areas.The research can provide a scientific and reliabletechnical support and a demonstration for coal mining and gas extraction in gaseous deepmulti-seams with low permeability.

Effects of Boundary Conditions on the Design of Anti-Ram Bollards

Anti-ram bollards used in perimeter protection are tested to meet performance requirements of established standards such as the US Department of State Specification SD-STD-02.01. Under these standards, tests are conducted in prescribed conditions that should be representative of the service installation. In actual project, conditions encountered on site may vary from the test environment and it would be expensive and time consuming to validate each deviation with a physical test. High-fidelity physics-based (HFPB) finite element modeling can provide precise simulations of the behavior of anti-ram bollards. This paper presents the use of HFPB finite element modeling, using LS-DYNA, in an actual project to evaluate the performance of an anti-ram bollard design subjected to various boundary conditions representing the physical conditions encountered on site. The study shows that boundary conditions can have a significant influence on the performance of the anti-ram bollards. This suggests that anti-ram bollards must be designed and engineered according to actual conditions that are found on site. It also shows that HFPB modeling can be an effective tool that supplements physical testing of anti-ram bollards.

Hydrodynamics features of dispersed bubbles in the ventilated wake flow of a cylinder

An experimental study was conducted to investigate the 2 D bubbly flow downstream of a cylinder. Sparsely distributed bubbles were produced using the ventilation method. The carrier flow was measured using the particle image velocimetry(PIV) technique. The shadow imaging technique was used to capture instantaneous bubbly flow images. An image-processing code was compiled to identify bubbles in acquired image, calculate the bubble equivalent diameter and the bubble velocity. The effects of Reynolds number and the flow rate of the injected air were considered. The result indicates that the carrier flow is featured by distinct flow structures and the wake region is suppressed as the upstream velocity increases. Regarding the bubbles trapped in the wake flow, the number of small bubbles increases with the upstream velocity. On the whole, the bubble velocity is slightly lower than that of the carrier flow. The consistency between small bubbles and the carrier flow is high in terms of velocity magnitude, which is justified near the wake edge. The difference between the bubble velocity and the carrier flow velocity is remarkable near the wake centerline. For certain Reynolds number, with the increase in the air flow rate, the bubble equivalent diameter increases and the bubble void fraction is elevated.

Study and simulation on the characteristics of drill string channel for acoustic waves

Traditional wireless MWD telemetry systems such as mud pulse and electromagnetic telemetry are limited due to low carrier frequencies. The first acoustic telemetry system was studied as part of a drill stem testing system in 2000, but there are some problems limited it to using for information transmission in drilling. In the paper, we study and simulation on the drill string channel characteristics. Based on the transmission equation of longitudinal wave in periodic drill string channel, we get a geometrical model for drill string channel. Two aspects are studied. Firstly, the equation for dispersion is established analyze and simulate the influence of length and cross-section to dispersion. Secondly, we introduce finite-difference for analyzing of transient response. Simulate transient response of drill string channel by changing the geometrical-characters of drill string. The paper gets characteristics of channel dispersion and signal attenuation, and useful for the choosing of best passband for carrier frequency. It is valuable for the acoustic telemetry to use for drilling applications.

Dynamic characteristics of the high-flow water three-way valve

Operating principle of water three-way valve with high flow for individual hydraulic prop in coal was presented in this paper, its strict and precise mathematical model was established, its flow field was simulated numerically by software Fluent, and its dynamic characteristics were analyzed during the work process such as raising leg, loading and overflow, the influence of the related parameters on high-flow water three-way valve was determined. The results as follows： during the raising leg stage and early raising leg stage, when the damping ratio increases, the overshoot of system decreases and the setting time reduces, and the dynamic response performance has a significant improvement. During the loading stage and the overflow stage, the pressure in plunger chamber of single hydraulic prop, the output flow and the displacement of the high-flow water three-way valve decrease with the decreasing of the external load. The spring stiffness of the safety valve directs the flow and the spool＇s displacement of the safety valve, and it can be used to control the high-flow three-way valve＇s sensitivity.

A General Method to Study the Sound Radiation of a Finite Cylindrical Shell Based on Elastic Theory

A general method was proposed to study the sound and vibration of a finite cylindrical shell with elastic theory. This method was developed through comprehensive analysis of the uncoupled Helmholtz equation obtained by the decomposition of elastic equations and the structure of the solution of a finite cylindrical shell analyzed by thin shell theory. The proposed method is theoretically suitable for arbitrary thickness of the shell and any frequency. Also, the results obtained through the method can be used to determine the range of application of the thin shell theory. Furthermore, the proposed method can deal with the problems limited by the thin shell theory. Additionally, the method can be suitable for several types of complex cylindrical shell such as the ring-stiffened cylindrical shell, damped cylindrical shell, and double cylindrical shell.

地震灾害对文化遗存的影响与文物抗震保护的历史经验——以四川省平武报恩寺古建筑为例

2008年5月12日14时28分,四川省汶川县发生了里氏8级特大地震。这场浩劫不仅夺去了无数生命,也给四川省多处珍贵文化遗产带来了前所未有的损毁。经国家文物局抗震救灾工作组统计,四川全省包括都江堰、汶川、北川。

陈毅走险

1935年10月,原中央革命根据地军区参谋长龚楚叛变投敌后,被广东军阀陈济棠封为少将“剿共游击司令”,并配给一支一色快枪和德式驳壳枪的40人卫队。龚楚将卫队伪装成“红军游击队”,屡屡破坏我赣粤边游击领导中枢,还企图捕捉项英、陈毅。叛徒一手策划了“北山事件”,我北山区委、游击队、仓库、修械所、被服厂和交通站的50多位领导人和干部牺牲。

略谈门球战术的新发展

二十年来,门球的高手精英们,创造了许多新的战术招法,其中以王牌球、双杆球,利用对方球战术,最为普遍盛行。下面仅以个人浅见,略谈这三项战术的形成和发展,与球友们交流探讨。

Experimental investigation on coherent structures at early stage of boundary layer bypass transition induced by wake impingement

The early stage of a boundary layer bypass transition induced by the direct impingement of a circular cylinder wake is experimentally investigated in water tunnel,with the primary interest in both the evolution of coherent structures and their effects on the disturbance growth inside the boundary layer.It is found that spanwise vortices with small scale first form in the near-wall region around the leading-edge,which are either the residual of the wake rollers cut by the leading-edge or the high-order structures induced by the wake rollers.The formation of these spanwise vortices leads to the first rapid disturbance growth inside the boundary layer.On the other hand,streamwise vortices,which result from the impingement of longitudinal braids onto the leading-edge,are also observed inside the boundary layer.They lead to the three dimensional destabilization and the subsequent dispersion of spanwise vortices,and soon become the most dominant coherent structures inside the transitional boundary layer.It is suggested that the formation and evolution of these streamwise vortices contribute to the secondary disturbance growth stage and thus promote the completion of the transition process.The difference between the present transition scenario triggered by direct wake impingement and that by indirect wake-vortex inducement is further discussed.

Xinfeng capsule improves pulmonary function in ankylosing spondylitis patients via NF-κB-iNOS-NO signaling pathway

OBJECTIVE: To study changes in the nuclear factor-κB p65(NF-κB p65)-inducible nitric oxide synthase(i NOS)-nitric oxide(NO) signaling pathway and the effects of Xinfeng capsules(XFC) in patients with ankylosing spondylitis(AS)METHODS: One hundred twenty patients with AS were randomly divided into an XFC group and a Salazopyrin group. Sixty health subjects were included as a normal control group. In the two treatment groups, pulmonary functional parameters,forced vital capacity(FVC), forced expiratory volume in 1 second(FEV1), maximal voluntary ventilation(MVV), peak expiratory flow(PEF), forced expiratory flow at 25% of forced vital capacity(FEF25),forced expiratory flow at 50% of forced vital capacity(FEF50), and forced expiratory flow at 75% of forced vital capacity(FEF75) were determined. Enzyme linked immunosorbent assays were used for detection of the serum oxidative stress indexes,NF-κB p65, i NOS, NO, reactive oxygen species(ROS), reactive nitrogen species(RNS), malondialdehyde(MDA), superoxide dismutase(SOD), catalase(CAT), total antioxidative capacity(TAOC) and interleukin-4(IL-4), IL-10, IL-1β, and tumor necrosis factor-α(TNF-α) contents. Westergren's method was used for determination of erythrocyte sedimentation rate(ESR). High-sensitivity C-reactive protein(Hs-CRP) was detected with a 7060 full-automatic biochemical analyzer(Hitachi, Japan).RESULTS: The clinical therapeutic effect in the XFC group was significantly superior to that in the Salazopyrin group(P<0.01). Compared with the normal control group, FEV1, MVV, PEF, FEF50, FEF75, SOD, CAT,TAOC, IL-4, IL-10 were significantly lower, and NF-κB p65, i NOS, NO, ROS, RNS, MDA, IL-1β, TNF-α, ESR,and Hs-CRP significantly higher in patients with AS(P<0.01 or P<0.05). Compared with before treatment, FEV1, MVV, PEF, FEF50, FEF75, SOD, CAT, TAOC,IL-4, and IL-10 were significantly increased, and NF-κB p65, i NOS, NO, ROS, RNS, MDA, IL-1β, TNF-α,ESR, CRP, visual analog scales(VAS), Bath ankylosing spondylitis disease active index, Bath ankylosing spondylitis functional index, and Bath ankylosing spondylitis global index significantly decreased in the two treatment groups after treatment(P<0.01 or P<0.05), with significant differences between the XFC and Salazopyrin groups(P<0.01 or P<0.05). Spearman correlation analysis indicated that FEV1, MVV, PEF, FEF50, and FEF75 were positively correlated with SOD, CAT, TAOC, IL-4, and IL-10, and were negatively correlated with NF-κB p65, i NOS,NO, ROS, RNS, MDA, IL-1β, TNF-α, ESR, and CRP.CONCLUSION: Patients with AS have local pathologic changes in the spinal cord and other joints.They also have decreased pulmonary function,which is negatively correlated with the NF-κB-i NOS-NO signaling pathway, oxidative indexes, and inflammatory factors. XFC improves rigidity and pain in spinal joints and other symptoms, laboratory indexes, and pulmonary function. The mechanism is possibly related to inhibition of the NF-κB-i NOS-NO signaling pathway.