气泡在粘弹性液体中溶解的研究进展

在发泡塑料的制造过程中，均相气体－聚合物体系的形成直接影响了制品的物理机械性能，因此了解气泡在粘弹性液体中的溶解机理成为必然。本文讲述了气泡在流体中塌陷行为的研究进展。对Rayleigh对低粘度牛顿流体，Foqer和Goddand在无线量线性Maxwell模型的粘弹性体，Tanasawa和Tang用oldroyd三常数粘弹模型等科学家的研究行为做了概述，总结出影响此过程的复杂的影响因素，并指出进一步的研究方向。     

摩擦强度对薄膜表面形态的作用:原子力显微镜下的观察

展示了摩擦强度对聚酰亚胺薄膜表面形态的影响，原子力显微图像显示，机械摩擦会使聚酰亚胺薄膜表面上形成微沟槽，这些沟槽的表面具有丰富的表面精细构造。原子显微图像还揭示了机械摩擦可以改变被磨擦聚酰亚胺膜的表面形态。     

聚乙烯醇侧链液晶的结构与液晶性研究

研究了聚乙烯醇侧链液晶主链分子量和液晶基元等结构因素对其液晶性的影响，结果表明随着聚合物的分子量增加，导致复合物清亮点温度下降。但是在液晶主链尚未被液晶基元饱和之前，随着液晶基元相对主链摩尔比的增加，样品形成较为完善的氢键结构。     

Acoustic emission method for research and control of friction pairs

One of the new physical methods that provides much information about the processes going on in a friction contact zone in real time is acoustic emission (AE). Basic experimental results of AE in friction are presented and analysed. Using AE signals we can get an indication about the state of the friction processes, about the quality of solid and liquid layers on the contacting surfaces in real time, sometimes about intensity of wear, changing of wear and friction regimes and so on. The influence of sliding velocity, load, roughness and some physical and mechanical properties of the body on the parameters of AE are also given. Some attention to the practical implementation of these techniques for control of capability for work of friction pairs in real conditions are given. Modern methods and devices enable condition monitoring of sliding and rolling bearings.     

啤酒酵母菌种的石蜡保藏技术

啤酒酵母菌种用液体石蜡技术保藏具有设备简单、操作方便,成活率高,变异少,优良种性能保持较长时间的优点,实用价值高。本文从液体石蜡保藏菌种的机理、保藏效果、保藏等具体技术操作及其使用方法都作了较为详细的介绍,相信能为啤酒菌种的保藏带来较大的好处。     

将紫外光谱用于溴指数测定方法的选择

对未知组成的样品进行紫外光谱扫描 ,根据扫描结果以及各种溴指数测定方法的适用范围 ,选择测定未知物溴指数的适宜方法 ,以提高测定准确度。     

氨氮监测中样品蒸馏预处理对结果的影响分析

氨氮监测采用预蒸馏处理后，比色测定结果明显偏低。在样品预蒸馏处理过程中，硼酸作为吸收液，使显色时溶液pH值偏低，导致显色不充分是其主要影响因素。通过采取增加显色剂加入量的方法，解决了显色pH值偏低的问题，得到满意的测定结果。     

The GENIUS-test-facility—first results on background from Rn daughters

GENIUS-TF (Nucl. Instr. and Meth. A 511 (2003) 341; Nucl. Instr. and Meth. A 481 (2002) 149.) is a test-facility for the GENIUS project (GENIUS-Proposal, 20 November 1997; Z. Phys. A 359 (1997) 351; CERN Courier, November 1997, 16; J. Phys. G 24 (1998) 483; Z. Phys. A 359 (1997) 361; in: H.V. Klapdor-Kleingrothaus, H. Pas. (Eds.), First International Conference on Particle Physics Beyond the Standard Model, Castle Ringberg, Germany, 8–14 June 1997, IOP Bristol (1998) 485 and in Int. J. Mod. Phys. A 13 (1998) 3953; in: H.V. Klapdor-Kleingrothaus, I.V. Krivosheina (Eds.), Proceedings of the Second International Conference on Particle Physics Beyond the Standard Model BEYOND’ 99, Castle Ringberg, Germany 6–12 June 1999, IOP Bristol (2000) 915), a proposed large scale underground observatory for rare events which is based on operation of naked germanium detectors in liquid nitrogen for an extreme background reduction. Operation of naked Ge crystals in liquid nitrogen has been applied routinely already for more than 20 years by the CANBERRA Company for technical functions tests (CANBERRA Company, private communication, 5 March 2004.), but it never had found entrance into basic research. Only in 1997 first tests of application of this method for nuclear spectroscopy have been performed, successfully, in Heidelberg (Klapdor-Kleingrothaus et al., 1997, 1998; J. Hellmig and H.V. Klapdor-Kleingrothaus, 1997).

On May 5, 2003 the first four naked high-purity germanium detectors (total mass 10.52 kg) were installed in liquid nitrogen in the GENIUS Test Facility at the Gran Sasso underground laboratory. Since then the experiment has been running continuously, testing for the first time the novel technique in an underground laboratory and for a long-lasting period.

In this work, we present the first analysis of the GENIUS-TF background after the completion of the external shielding, which took place in December 2003. We focus especially on the background coming from ²²²Rn daughters. This is found to be at present by a factor of 200 higher than expected from simulation. It is still compatible with the scientific goal of GENIUS-TF, namely to search for cold dark matter by the modulation signal, but on the present level would cause serious problems for a full GENIUS—like experiment using liquid nitrogen.     

Study of liquid injection impact on the performance of new refrigerant mixtures

In this paper, the test results of liquid injection impact on the performance of new alternative refrigerant mixtures such as: R-410A, R-507, R-407C and R-404A are discussed, analysed and presented. The test results were obtained using an air-source heat pump set-up with enhanced surface tubing under various liquid injection ratios. Performance tests were conducted according to the ARI/ASHRAE standards. The performance data demonstrated that as liquid injection ratio increases, compressor head pressure and discharge temperature decrease. This has a positive effect in protecting the compressor. The effect of liquid injection on mixture behaviour varies from one mixture to another depending upon the mixture's composition. Furthermore, liquid injection appears to have a significant influence on R-410A behaviour compared to the other mixtures in question. Copyright © 2002 John Wiley & Sons, Ltd.     

Elimination of organic matter present in wastewaters from the cork industry by membrane filtration

BACKGROUND: The first stage of the cork industrial process generates great volumes of wastewater with moderate to high organic pollutant content that must be purified using different procedures, such as filtration by membranes. RESULTS: The tangential filtration of these wastewaters was studied using two different laboratory equipments. In the first one, three ultrafiltration (UF) membranes were tested, with molecular weight cut‐off (MWCO) 100 kDa and 30 kDa, and two operating modes were used: total recycling of permeate and retentate streams, and in continuous mode, without recycling both streams. In the total recycling UF experiments, the influence of the operating variables on the permeate flux was first established. The effectiveness of the different membranes was determined by evaluating the rejection coefficients for several parameters that measure the global pollutant content of the effluent. The values found for these rejection coefficients were in the following order: ellagic acid and color > absorbance at 254 nm > tannic content > COD (chemical oxygen demand). In the continuous mode experiments, the fouling mechanism for each membrane was established by fitting the experimental data to various filtration fouling models given in the literature. The operating mode in the second equipment was batch concentration, and additional experiments were carried out with an UF membrane (2 kDa), and with a NF membrane (with MWCO in the range 150–300 Da). CONCLUSIONS: The three operating modes tested provided different rejection levels of organic matter; among them, the most effective procedure tested was batch concentration mode using a NF membrane. Copyright © 2007 Society of Chemical Industry