Qualitative and quantitative assessment of interior moisture buffering by enclosures

The significance of interior humidity in attaining sustainable, durable, healthy and comfortable buildings is increasingly recognised. Given their significant interaction, any interior humidity appraisal requires a qualitative and/or quantitative assessment of interior moisture buffering. While the effective moisture penetration depth and effective capacitance models allow quantified assessment, their reliance on the ‘moisture penetration depth’ necessitates comprehensive material properties and hampers their application to multidimensional interior objects. On the other hand, while various recently suggested protocols for the simple and fast measurement of the moisture buffer potential of interior elements allow qualitative assessment, none of these are currently dependable for a wide range of moisture production regimes.In response to these flaws, this paper introduces the production-adaptive characterisation of the moisture buffer potential of interior elements and corroborates their superposition toward a room-enclosure moisture buffer potential. It is verified that this enables qualitative comparison of enclosures in relation to interior moisture buffering. It is moreover demonstrated that it forms an alternative basis for quantitative evaluation of interior moisture buffering by the effective moisture penetration depth and effective capacitance models. The presented methodology uses simple and fast measurements only and can also be applied to multimaterial and/or multidimensional interior elements.     

芯片级原子钟的气密性能分析

基于相干布居囚禁(CPT)原理芯片级原子钟(CSAC)原子腔体积小、采用微电子机械系统硅-玻璃键合工艺制造,其气密性是决定CSAC寿命的关键因素。本文提出了"多层缓冲原子腔"方案大幅度提高原子腔的气密性能,从而提高CPT CSAC的稳定性和寿命。建立了一个"毛细管等效气流模型"模拟多层缓冲原子腔的泄漏以分析原子腔的气密性能,应用Matlab仿真对比了单层密封、多层密封、添加保护腔等不同方式下气密性能的改善幅度。仿真结果验证了"多层缓冲原子腔"在提高CPT CSAC物理系统气密性能方面的可行性和有效性,为原子腔的设计提供指导。     

Determination of azinphos-methyl and parathion-methyl in honey by stripping voltammetry

An electrochemical method for the determination of azinphos-methyl and parathion-methyl in honey is presented. The determination is established by adsorptive stripping differential pulse voltammetry at hanging mercury working electrode.In contrast to the chromatographic methods for the determination of pesticide residues, the sample preparation of the proposed method is minimal; analytes were extracted from honey samples with a mixture of (acetone):(Britton-Robinson buffer) and then were analyzed without any additional pretreatment.The response of the analytes either individually or as a mixture was studied for a series of deposition time and molar ratio. Two quantitation protocols were compared, using either the external calibration or the standard addition method. Accuracy was tested with spiked honey samples obtaining good recovery values. The limit of detection for the honey sample (for deposition time of 10 s) was calculated 51.71 μg kg⁻¹ for MeP and 65.87 μg kg⁻¹ for AzMet.     

pH measurement in the vicinity of a cathode evolving hydrogen gas using an antimony microelectrode

An antimony microelectrode was prepared by quenching a molten Sb–Sb2O3 mixture (2% Sb2O3). The local pH in the vicinity of a cathode evolving hydrogen gas was directly measured using the microelectrode. The local pH during electrolysis of KCl-glycine aqueous solutions was increased by proton consumption; however, the increment decreased with increasing concentrations of glycine, a buffering agent. The diffusion-limiting current density of hydrogen evolution involving proton reduction was controlled by the concentrations of the proton-donating species: protonated-glycine +H3NCH2COOH and H3O+ ions. A plot of the current density against the sum of the concentrations gives a single straight line passing through the origin. The phenomena are discussed in terms of electrodeposition processes of base metals.     

A high-performance IGBT with new N+ buffer structure

We propose a new IGBT structure with a new N⁺ buffer, and confirm by experiments and numerical simulations that the new IGBT is superior to the conventional one. The following results were obtained. (1) According to our experiments, the new IGBT was able to decrease the total power loss, and the parallel operation became easier, compared with the conventional IGBT. Moreover, the short-circuit ruggedness of the new IGBT was almost the same as that of the conventional one by optimizing the ratio of the N⁺⁺ buried layer. (2) We clarified why the characteristics of the new IGBT were improved by numerical simulations. (a) When the new IGBT is on, holes injected from the P⁺ substrate flow through, remaining out of the N₊₊ buried layer. Also, the holes rapidly turn around in the N⁺⁺ buried layer when passing by, and the hole concentration becomes even. Because the lifetime of the new IGBT is designed to be long, the hole concentrations of the new IGBT increases in the N^? layer. Therefore, the saturation voltage of the new IGBT is lower than that of the conventional IGBT. (b) Since the lifetime of the N^? layer of the new IGBT can be extended, the temperature dependence of the lifetime becomes small, and IZTC of the new IGBT is improved. (c) In the turn-on state, the holes are injected through the N⁺ buffer layer with lower concentration from the P⁺ substrate, thus the turn-on speed of the new IGBT become quicker and the turn-on loss of the IGBT is reduced. (d) In the turn-off state, as the N^? layer is depleted completely, the carriers in the N⁺ buffer layer mainly influence the tail current. There are few carriers in the N⁺⁺ buried layer of the new IGBT, so the turn-off loss of the new IGBT is reduced. (e) Since the effect to prevent the holes being injected from the P⁺ substrate affects the N^? layer, the number of carriers of the N^? layer of the new IGBT is limited in the saturation current region. Therefore, the saturation current is also controlled, and the short-circuit ruggedness of the new IGBT is not diminished.     

长大管棚法在处理炭质千枚岩坍方中的应用

叙述了引水隧洞炭质千枚岩粉末夹杂少量块体的大坍体中，采用跟管钻进打设大口径长管棚支护的工艺技术和钻进方法，最后提出几点经验和体会，工程取得了良好的效益，可推广该方案的应用。     

Simulations of THM processes in buffer-rock barriers of high-level waste disposal in an argillaceous formation

The main objective of this paper is to investigate and analyse the thermo-hydro-mechanical (THM) coupling phenomena and their influences on the repository safety. In this paper, the high-level waste (HLW) disposal concept in drifts in clay formation with backfilled bentonite buffer is represented numerically using the CODE_BRIGHT developed by the Technical University of Catalonia in Barcelona. The parameters of clay and bentonite used in the simulation are determined by laboratory and in situ experiments. The calculation results are presented to show the hydro-mechanical (HM) processes during the operation phase and the THM processes in the after-closure phase. According to the simulation results, the most probable critical processes for the disposal project have been represented and analyzed. The work also provides an input for additional development regarding the design, assessment and validation of the HLW disposal concept.     

选煤厂溜槽减振降噪的设计与应用

通过对选煤厂溜槽噪声的分析,介绍了几种在选煤生产中常用的溜槽减振降噪方法,并阐述了各方法的减振降噪原理与特点,为选煤生产中溜槽噪声的治理提供了借鉴。     

Design of Two‐Stage Class AB CMOS Buffers: A Systematic Approach

A systematic approach for the design of two‐stage class AB CMOS unity‐gain buffers is proposed. It is based on the inclusion of a class AB operation to class A Miller amplifier topologies in unity‐gain negative feedback by a simple technique that does not modify quiescent currents, supply requirements, noise performance, or static power. Three design examples are fabricated in a 0.5 µm CMOS process. Measurement results show slew rate improvement factors of approximately 100 for the class AB buffers versus their class A counterparts for the same quiescent power consumption (< 200 µW).     

缓冲型拉索减震支座拟静力试验及减震效果分析

为了能够更有效地解决桥梁在地震中的力与位移平衡的问题,结合拉索减震支座的构造特点,提出了缓冲型拉索减震支座的构想,介绍了其工作原理以及实现方式,对常规拉索减震支座及缓冲型拉索减震支座进行拟静力试验,并将试验结果进行对比研究. 在试验结果的基础上提出了缓冲型拉索减震支座的数值模拟方法,并验证了所提方法的正确性. 最后,针对一座实际的连续梁桥,选用3条近场脉冲型地震波,分析采用拉索减震支座以及缓冲型拉索减震支座下的支座减震效果. 结果表明:相比于拉索减震支座,采用缓冲型拉索减震支座可以使结构的峰值支座位移、墩底最大弯度以及残余位移均有不同程度的降低,具有更好的限位能力和自复位能力.