Stability of Standard Electrolytic Conductivity Solutions in Glass Containers

The stability of solutions having an electrolytic conductivity, κ, of 5 μS/cm to 100 000 μS/cm packaged in glass screw-cap bottles, glass serum bottles, and glass ampoules was monitored for 1 year to 2 years. The conductivity was determined by measuring the ac resistance of the solution. Mass loss was also monitored for solutions packaged in bottles. The solutions were prepared using KCl in water (κ ≥100 μS/cm) or KCl in 30 % (by mass) n-propanol 70 % (by mass) water (κ ≤ 15 μS/cm). The conductivity changes were compared by packaging type and by nominal κ. The main causes of the κ changes are evaporation (screw-cap bottles) and leaching (screw-cap bottles, serum bottles, and ampoules). Evaporation is determined from mass loss data; leaching occurs from the glass container with no change in mass. The choice of optimal packaging, which depends on the conductivity level, is the packaging in which κ changes the least with time. Ampoules are the most suitable packaging for standards having nominal κ values of 500 μS/cm to 100 000 μS/cm. Screw-cap bottles are most suitable for standards having a nominal κ of 5 μS/cm to 100 μS/cm.     

THE LAURENCE BISHOP SILVER MEDAL INAUGURAL LECTURE THE IMPACT OF SCIENTIFIC MEASUREMENT ON THE BREWING PROCESS

Laurence Bishop's contribution to the brewing industry over more than 50 years of research endeavour and committee activities is reviewed. Three research areas — prediction of extract, the effect of turbidity on yeast activity during fermentation and the development of a 3-vessel fermentation system — are used to highlight his achievements. Five topics with which the author was intimately involved, three of which were connected with Laurence Bishop's own researches, are used to describe the author's activities. These concerned the assessment of beer foam, the prediction of beer stability, the assessment of the bittering value of hops, time course changes in the analytical characteristic of an ale fermentation and the use of fractional factorial designs to facilitate experimental programmes.     

电容位移法精确测量磁性薄膜的磁致伸缩系数

介绍了一种精确测量磁性薄膜磁致伸缩系数方法－电容位移法，并自行研制组装了一套测量装置，通过误差分析，仪器的精确标定，对稀土－铁超磁致伸缩薄膜的磁致伸缩系数进行了测量，获得满意的结果。     

热释电系数的测量方法

描述热释电系数的两种测量方法。其一为电荷积分法，测试系统简单，测量数据准确，且能满足零电场条件下的测量。其二为动态电流法，采用调制热源技术，研究在特定温度条件下热释电材料的动态热释电响应。     

Adaptive predictive control algorithm based on Laguerre Functional Model

Laguerre Functional Model has many advantages such as good approximation capability for the variances of system time‐delay, order and other structural parameters, low computational complexity, and the facility of online parameter identification, etc., so this model is suitable for complex industrial process control. A series of successful applications have been gained in linear and non‐linear predictive control fields by the control algorithm based on Laguerre Functional Model, however, former researchers have not systemically brought forward the theoretical analyses of the stability, robustness, and steady‐state performance of this algorithm, which are the keys to guarantee the feasibility of the control algorithm fundamentally. Aimed at this problem, we introduce the principles of the Incremental Mode Linear Laguerre Predictive Control (IMLLPC) algorithm, and then systemically propose the theoretical analyses and proofs of the stability and robustness of the algorithm, in addition, we also put forward the steady‐state performance analysis. At last, the control performances of this algorithm on two different physical industrial plants are presented in detail, and a number of experimental results validate the feasibility and superiority of IMLLPC algorithm. Copyright © 2005 John Wiley & Sons, Ltd.     

高质量的一级光栅1．55μmDFB激光器

本文详细叙述了ＤＦＢ激光器的设计要点和新的工艺。采用一级全息光栅和二步液相外延法批量研制出高稳定单纵模工作的１．５５μｍ分布反馈激光器（ＤＦＢ—ＬＤ）。外延片成品率＞４０％。器件特性：２５℃时阈值电流２０ｍＡ，单面光功率＞１０ｍｗ，主边模抑制比ＳＭＳＲ达４３ｄＢ（λ／４相移光栅），谱线宽度△ν－２０ｄＢ＝０．３ｎｍ，调制速率＞１．８ＧＨｚ。可靠性测试显示：高温监测光谱稳定，２５°Ｃ时阈值退化率△Ｉｔｈ／ｔ＜０．３ｍＡ／ｋｈ，对应器件预估寿命将超过１０万ｈ。     

3961连续重整催化剂性能考察

新一代高活性，高水热稳定性3961（PS－Ⅳ）型连续重整催化剂于1996年在上海石化芳烃厂400kt/a连续重整装置上首次进行工业应用试验。开工5a，催化剂跟踪分析结果表明，该剂保持了良好的物化性质和反应性能，表现为良好的比表面积稳定性和持氯能力，经过200个以上再生周期的催化剂未发现有明显的相变和金属分散度的变化。     

Application of SiC-Si functionally gradient material to thermoelectric energy conversion device

Because of its high–temperature chemical stability, SiC ceramic is a promising material for high-temperature device applications such as thermoelectric energy converters. However, the electrical conductivity of SiC ceramic is too low for it to be used as a thermoelectric energy converter at the cold junction. Therefore, we propose a SiC-Si functionally gradient material (FGM) in order to improve the electrical conductivity of the SiC ceramic at the cold junction. An SiC rod was fired in a temperature gradient furnace. One end of the SiC rod was maintained at 2473 K and the other end was maintained at 1973 K for 30 min. After firing, the porous SiC edge fired at 1973 K was dipped into molten Si in order to infiltrate molten Si into the porous SiC. The microstructure of the FGM is classified into three regions: the SiC-Si composite material; the porous SiC ceramic; and the densified SiC ceramic. The electrical conductivity, the Seebeck coefficient and the thermal conductivity for each region of SiC-Si FGM was measured at 300 K; a figure of merit was calculated. The figure of merit of the SiC-Si FGM at the cold junction, at room temperature, was 10⁸ times higher than that of a nongradient SiC ceramic.     

膨胀水泥浆体系在苏丹1/2/4区块水平井固井中的应用

随着苏丹1／2／4区块的深入开发，为了加快开发主力油层，提高原油产量，降低钻井成本，GNPOC在此区块布置水平井开发任务。所开发的区域主要分布于Heglig，Munga，Simbir，Bamboo区块，油层所在是Zaqar和Bentiue地层。此层位具有高渗透，地层温度高，易塌、气窜等复杂问题，尤其是Heglig和Munga地区井壁坍塌严重。为此，根据地质资料、井身结构和对水平井注水泥的技术要求，科学合理设计施工工艺，优选出适合此地区固井施工的冲洗液和隔离液，特别是经过努力实践，开发出了新型膨胀水泥浆体系，此体系具有高强度、低失水、无析水、防气窜之功效。结合使用哈里伯顿CPT—Y4大功率固井车，精确计量和自动密度控制，该体系水泥浆目前已在7口水平井施工中得以应用，均为优质井。现正在被大量使用，此体系的开发，解决了该固井技术难题，创造了中国固井在海外首次水平井作业一次成功的历史记录，具有较高的经济和社会效益。     

Stability analysis of an adaptive packet access scheme for mobile communication systems with high propagation delays

In this paper, we investigate a packet access scheme that is able to support mixed traffics in the presence of high propagation delays. Referring to a Time‐Code Division Multiple Access air interface, we propose a Medium Access Control (MAC) protocol based on a random access scheme. A successful attempt grants the use of a slot‐code resource. This protocol is named Adaptive Time Code‐Packet Reservation Multiple Access (ATC‐PRMA), since the access parameters are changed, depending on the traffic load conditions, so as to fulfil Quality of Service requirements. Numerical examples are carried out for the Low Earth Orbit (LEO)‐Mobile Satellite System (MSS) scenario, but all these considerations could be applied to High‐Altitude Platform Stations (HAPSs) as well. In both cases, high propagation delays prevent an immediate feedback to users. An analytical approach is proposed to study the stability of our MAC scheme. Accordingly, we define a criterion for optimizing system performance. The predicted ATC‐PRMA behaviour is supported by simulation results. Finally, we show the performance improvement of ATC‐PRMA with respect to a MAC protocol not employing adaptive parameters. Copyright © 2003 John Wiley & Sons, Ltd.