DC-DC电荷泵的研究与设计

以Dickson电荷泵的基本原理为出发点，研究了一种将正电压输入转为负电压输出的开关电容电路。由于开关电容的充放电特点，为确定电容时间常数，采用非交叠时钟控制信号避免了由于时钟交叠而造成的当电容充电还未完成即对下一级电容进行放电的现象。同时，参考功率MOS-FET的电容模型通过增大驱动电路的电流减小了开关管的上升延时，提高了开关动作的速度，使转换效率得到明显提高。此电路结构简单，性能优良，易于集成，可广泛应用于输出负电压的电源产品中。     

AUTOCONER-338型自动络筒机的接头工艺与切疵有效性分析

介绍了AUTOCONER-338型自动络筒机空气捻接器的接头要求与影响接头质量的因素,并且就不同品种的纱线选用不同接头工艺进行了简单分析;介绍了如何评价络筒切疵有效性与影响切疵率的因素.通过以上2方面的分析介绍,及时调整设计与工艺,提高了生产效率,改善了布面质量.     

Assessment of the energy and exergy utilization efficiencies in the Turkish agricultural sector

This study deals with evaluating the energy and exergy utilization efficiencies in the Turkish agricultural sector over a 12‐year period from 1990 to 2001. In the energy and exergy analyses, two main energy sources, namely fuels and electricity, are taken into consideration, while the sectoral energy and exergy efficiencies are compared for this period. These main energy sources include diesel for tractors and other vehicles, and electricity for pumps. Overall energy utilization efficiencies are obtained to vary between 29.1 and 41.1%, while overall exergy utilization efficiencies are found to range from 27.9 to 37.4% in the analysed years, respectively. It may be concluded that the present technique proposed here may be used as a useful tool in analysing and evaluating the energy and exergy utilization efficiencies, identifying energy efficiency and/or energy conservation opportunities and dictating the energy strategies of countries. Copyright © 2005 John Wiley & Sons, Ltd.     

美国节能管理工作特点及对我国的启示

本文比较系统地分析了美国节能管理工作的主要特点,并研究了美国的节能管理模式对我国推动节能工作的启示。文中首先介绍了美国推动节能工作的主要机构,然后从最低能耗标准、能效标识、节能工作参与群体的市场定位、基于市场的节能激励机制及政府机构节能等方面详细阐述了美国节能政策制定和实施的基本特点,并结合我国的国情分析了美国节能管理模式对我国节能工作的启示,最后提出了相关政策建议。     

Dental amalgam – the effect of the technology of alloy powder preparation on the corrosion behaviour and the release of mercury

Dental amalgams are based on a broad spectrum of materials differing in their chemical composition, metallurgical treatment, and in the way the initial alloys powders are prepared. In addition to their chemical composition, amalgams based on various powders differ in both their microstructure and the amount of mercury needed for preparation. All these facts may affect electrochemical processes occurring during their interaction with oral fluids, and also mercury release. While verifying the effect of the technology used for the preparation of the high‐copper ternary alloy powder on the properties of resulting amalgams, this study aimed at the mechanism of their interaction with a model saliva solution as well as mercury release was included. Measurements were done in a model saliva solution using standard electrochemical methods and exposition measurements. The interaction of individual types of amalgams with artificial saliva did not reveal any significant differences. The free corrosion potential of all these amalgams in an aerated solution settled in the range of values in which tin oxidation, resulting in a layer of insoluble corrosion producsts, turned out to be the dominant anodic process. The rate of mercury release was the lowest for amalgams based on a gas‐atomized alloy. The highest rate of mercury release, and also its dependence on time, was exhibited by lathe‐cut powder based amalgam. In addition to different volume fraction of the Ag‐Hg phase and the level of its tin alloying, this different behaviour may be explained by differences in the rate at which a layer of tin corrosion products acting as a barrier to mercury release is formed.     

Urea briquette applicator for transplanted rice

A plunger-type, completely hand-operated applicator prototype, made of polyvinyl chloride (PVC), for deep placement of urea briquettes (UB), i.e., pillow-shaped urea supergranules with edges, in line transplanted rice has been developed for use by small-scale rice farmers. The field evaluation of the applicator was conducted in the Philippines during the 1989 dry season. The applicator consistently placed UB at proper depth (7 to 8 cm), which resulted in low concentrations of urea N (<7 ppm) in about 4 cm of floodwater 1 day after placement. These findings indicated that the prototype worked properly. Average work output of the applicator was 0.20 ha workday^–1 and may increase with practice. The yields of irrigated transplanted rice in the field trials show that agronomic efficiencies of hand-placed UB and applicator-placed UB were equal and were superior to those of split-applied prilled urea.     

Process conditions for separating fatty acid esters by supercritical CO2

The solubilities of ethyl palmitate, ethyl oleate, ethyl eicosapentaenoate (EPA) and ethyl docosahexaenoate (DHA) in supercritical carbon dioxide were determined by a continuous flow method. The solubilities of fatty acid ethyl esters increased with pressure and decreased as the temperature was increased. An empirical equation, similar to Chrastil's equation, was used to describe the relationship between solute solubility and the density of carbon dioxide. The empirical equation was further used to qualitatively estimate the separation efficiency of isolating EPA and DHA ethyl esters from fatty acid esters. The operating conditions yielding high solubility gave fast extraction rate but resulted in low separation efficiency. Experiments were conducted to separate ethyl EPA and ethyl DHA from a model mixture containing four fatty acid ethyl esters and from esterified squid visceral oil. The experimental data compared closely with the calculated values.     

带有块间串扰MC-CDMA的时域信道估计和多用户检测

本文把带有IBI的MC-CDMA系统等效解释为特殊的直接序列码分多址（DS-CDMA）系统，并给出了相应的时域信道估计方法和时域线性最小均方误差（MMSE）多用户检测方法。仿真实验表明了本文方法的性能。     

覆膜滤料的滤尘性能测试方法研究

由于覆膜滤料的结构和性能有别于普通滤料，因而普通滤料的滤尘性能测试方法不完全适用于覆滤料。本文作者在总结实践经验的基础上，提出了在覆膜滤料的滤尘性能测试中应注意的一些问题和应增加的测试项目。