风冷压缩单元式空调器节能探讨

从分析风冷压缩单元式空调器的制冷原理入手,提出了两种空气源热泵热水模块＋空气源压缩制冷模块机,为提高能源综合利用效率、节约建筑能耗提供了一定的实践思路。     

Low-complexity audio CODEC for resource-scarce embedded system with fixed-point arithmetic

This work presents a low-complexity audio coder-decoder (CODEC) based on fixed-point arithmetic to save the usage of system resources in a low-end embedded system. To reduce time complexity and memory usage, a simplified discrete wavelet transform (DWT) with only integer operations is developed. The simplified DWT reduces the computation that is required for the trigonometric operations in the fixed-point system. Moreover, separating the even and odd orders of wavelet coefficients halves the computation time of the original DWT. Additionally, a tri-mode zeroes recording algorithm (TZRA) is proposed. The proposed TZRA utilizes different encoding modes with their corresponding bit data structures to record the locations of zero wavelet coefficients, and determines the optimal encoding mode that uses the fewest bits. To further improve the compression performance, a dynamic wavelet level selecting algorithm is developed to decide the wavelet level for compressing each of frame. This algorithm can dynamically select the optimal wavelet level with the fewest bits by using the determined mode from the TZRA. The experimental results herein reveal that the encoder in the proposed CODEC can multiply computation by factors of 164 and 112 and reduce the size of the execution file by approximately 95.61 and 98.42% relative to baseline audio compression CODECs. Such results indicate that the efficiency when used in real consumer products with fixed-point arithmetic.     

基于纳米压缩跨平台高负载手游的技术开发

现如今，智能手机的使用非常普遍，3G和4G网络也大规模的发展和普及，手机游戏市场随之在不断扩大，手机游戏用户也在日渐增多。因此,研究适于手机平台的网游服务端关键技术具有很重要的现实意义和应用价值。     

Loadbearing capacity of infill masonry walls considering the deformation‐based membrane effect

According to currently valid codes, it is not possible to determine the loadbearing capacity of unreinforced infill walls considering the deformation‐based membrane effect by incorporating the exact support conditions. One reason for this is the lack of a validated calculation procedure, which in addition to the equilibrium conditions also realistically represents the compatibility conditions of these systems. In the present paper, therefore, a new non‐linear analytical calculation procedure is presented. The main focus of the analysis of walls subject to area loading is the incorporation of the support conditions and thus the consideration of the deformation‐based membrane compressive force. Through generalised formulation and a standardised notation of the determination equations, different material behaviours and various support conditions can be taken into account with few parameters. On the action side, both lighter loading like wind loads and heavier loading like explosion loads can be considered. Through the implementation of the partial factor concept, it is possible to comply with the requirements of European codes and thus ensure the applicability of the analysis model.     

DYL高速视频12位DAC的研制

文中介绍了以我国独创的DYL多元逻辑电路为基础,并配合了申请国家发明专利的高速差动电压模拟开关构成的12位高速DAC转换器。同时解决了以往高速转换器输出阻抗、使用范围受限的缺点。同时对所研制的高速DAC在结构、工艺、修正技术及测试上进行了多方面的研究探讨。     

Using rapid compression machines for chemical kinetics studies

Rapid compression machines (RCMs) are used to simulate a single compression stroke of an internal combustion engine without some of the complicated swirl bowl geometry, cycle-to-cycle variation, residual gas, and other complications associated with engine operating conditions. RCMs are primarily used to measure ignition delay times as a function of temperature, pressure, and fuel/oxygen/diluent ratio; further they can be equipped with diagnostics to determine the temperature and flow fields inside the reaction chamber and to measure the concentrations of reactant, intermediate, and product species produced during combustion.This paper first discusses the operational principles and design features of RCMs, including the use of creviced pistons, which is an important feature in order to suppress the boundary layer, preventing it from becoming entrained into the reaction chamber via a roll-up vortex. The paper then discusses methods by which experiments performed in RCMs are interpreted and simulated. Furthermore, differences in measured ignition delays from RCMs and shock tube facilities are discussed, with the apparent initial gross disagreement being explained by facility effects in both types of experiments. Finally, future directions for using RCMs in chemical kinetics studies are also discussed.     

The Use of Surface Analysis Techniques to Determine the Route of Manufacture of Tablet Dosage Forms

ABSTRACT

Analytical methods for determining the manufacturing process of tablet dosage forms have not been previously reported. The use of surface analysis techniques in particular X-ray Photoelectron Spectroscopy and Time of Flight Secondary Ionization Mass Spectrometry will be described and a model proposed which allows the prediction of the route of manufacture in calcium phosphate and cellulosic-based tablet formulations. Results of the application of this model to evaluate prototype tablet formulations prepared by wet granulation or direct compression will be reported. Strengths and limitations of the model will be discussed.     

基于MAC序列的相位编码准连续波的研究与应用

本文在讨论用二相编码信号构成的准连续波的数学模型和模糊函数的基础上,引入新的二元序列--MAC序列,并对其产生以及自相关特性进行了详细研究。通过对采用该序列编码的准连续波信号的周期单码重复时和多码重复的模糊函数进行仿真,其结果具有很好的图钉状,即有较高的距离和多普勒分辨率;并将MAC序列的相位编码准连续波应用在波形设计中,脉压仿真结果表明相比较m序列码,MAC序列更适用于目标检测。     

Storage devices for heat exchangers with phase change

Heat exchangers with phase-change achieve minimal dissipation when there is only a small temperature difference between the inlet and the outlet on the side of the sensible heat transfer medium. However, this does not usually occur in applications where these heat exchangers are typically used. In order to overcome this issue, an innovative prototype heat pump was realised. The heat pump was equipped with switchable storage devices to adapt the high temperature difference of the application to small temperature differences in the condenser. This way, the dissipation in the condenser was minimised, which led to COP increases by reducing the required mean pressure in the condenser. The use of storage devices resulted in measured efficiency improvements of 10%–50% in the prototype. With the described set-up, it is possible to approach the maximal thermodynamically possible COP, which makes an adaptation of the theoretical assessment of heat pumps necessary.     

多路时移电视节目系统

单向数字电视系统业务单一，不能满足人们的需要，时移电视系统应运而生。改变了人们的收视习惯，完善了数字电视的功能。重点介绍库车县广播电视局22路时移电视节目系统的组成，22路时移电视节目的制作及注意事项。