Effect of strain waveform on creep-fatigue life for Sn–8Zn–3Bi solder

This paper describes the creep‐fatigue life of Sn–8Zn–3Bi under push–pull loading. Creep‐fatigue tests were carried out using Sn–8Zn–3Bi specimens in fast–fast, fast–slow, slow–fast, slow–slow and hold–time strain waveforms. Creep‐fatigue lives in the slow–slow and hold‐time waveforms showed a small reduction from the fast–fast lives but those in the slow–fast and fast–slow waveforms showed a significant reduction from the fast–fast lives. Conventional creep‐fatigue life prediction methods were applied to the experimental data and the applicability of the methods was discussed. Creep‐fatigue characteristics of Sn–8Zn–3Bi were compared with those of Sn–3.5Ag and Sn–37Pb.     

Effect of the Chiral Center Position of an Optically Active Terminal Group on the Induction of Optical Activity in Polysilanes

Summary Polysilanes with an optically active alkoxy group, i.e., (S)-(+)-2-butoxy, (R)-(-)-2-butoxy, (S)-(-)-2-methyl-1-butoxy, and (S)-(+)-3,7-dimethyl-1-octoxy, at the terminal positions, the chiral carbon centers of which were located at the α, β, and γ positions relative to the oxygen, respectively, were prepared, and the effect of the position of chiral center of the terminal optically active group on the induction of optical activity in polysilanes was investigated. The circular dichroism (CD) spectra of these polymers showed positive Cotton signals around 340 nm at temperatures below -20 °C, but the intensities were small, indicating that the optically active groups at the terminal positions have some ability, albeit small, to induce optical activity to the polysilanes. Further, the optically active (S)-(+)-2-butoxy and (R)-(-)-2-butoxy groups did not control the helical sense direction of the polymers, despite the different chiral stimuli from the 2-butoxy groups introduced to the terminal positions. To control the helical structure of polysilanes by the use of optically active terminal groups, appropriate optically active groups are required.     

Terminal defined chain-growth polycondensation of 4-chloropyridine

This work examines the polycondensation of 4-chloropyridine derivatives using an N-(4-tert-butylbenzyl)-4-chloropyridinium (BPymCl) initiator and ion exchange reagents NaBPh₄, NaBF₄, and TBABF₄. The ¹H NMR spectra demonstrate that the product quantity is proportional to the total conversion of the monomer and the initiator. The MALDI-TOF MS spectrum shows that the product contains more than 9 monomer units. The polymerization was well-terminated via the addition of dimethylaminopyridine. These results indicate that the polycondensation proceeds in a chain-growth manner. This polycondensation could be a new example of a controlled polymerization with a well-defined end group.     

强制性的产品认证与电磁兼容的认证测试

文章阐述了强制性产品认证的重要意义，介绍了第一批实施强制性产品认证的产品目录及实施时间。重点介绍了电磁兼容的认证测试问题，对读者在标准、法律、法规方面提供帮助。     

Influence of Drying Methods on Volatile Sulfur Constituents of Caucas (Allium victorialis L.)

The effects of freeze-drying, hot air, and vacuum far infrared-drying on caucas (Allium victorialis L.) flavor was studied. The GC and GC-MS characterization of volatiles from dried caucas powders revealed the main flavor components; disulfides and trisulfides, as well as the antithrombotic substances; vinyldithiins, remained in all products. Vi-nyldithiins were isolated and subsequently confirmed by IR, NMR and Mass Spectrometry. Rehydration of the dried powders increased measurable volatile compounds, which were produced enzymatically. Increased-storage time decreased measurable volatiles in freeze-dried and hot air-dried caucas powders while the volatile profile remained unchanged.     

试论电合成高氯酸钠的理论分解电压

采用能斯特方程和吉布斯—赫姆荷茨方程论证推导出氯酸钠溶液的理论分解电压，对电合成高氯酸钠有着十分重要的指导意义。     

氯乙烯气柜的安全运行

介绍了氯乙烯气柜的结构、工作原理以及在生产中的作用,分析了气柜运行存在的安全风险和控制措施,并对气柜是否取消提出了建议。     

冷却塔小间距淋水填料特性研究

通过对组装高度1 m、板间距22 mm的改型小间距斜折波淋水填料的性能试验研究,采用最小二乘法整理出该种淋水填料的热力及阻力特性方程式,并与板间距为30 mm的常规淋水填料的特性进行比较发现,在逆流式自然通风冷却塔常用气水比范围内,改型淋水填料的热力特性比常规间距淋水填料提高21％～28％,通风阻力为常规间距淋水填料阻力的83％～99％.将改型斜折波淋水填料应用于5 000 m2自然通风冷却塔,经计算其出塔水温比采用常规间距斜折波淋水填料时的出塔水温降低约1℃,冷却效果显著提高.     

EXTRACTION OF METAL IONS WITH DZEHPA FROM MIXED AQUEOUS-ORGANIC MEDIA

Extraction of metal ions from the aqueous-organic solution containing dimethyl formamide(DMF), dimethyl sulfoxide(DMSO) and acetonitrile(AN) was investigated by using di-2-ethylhexyl-phosphoric acid(D2EHPA) as an extractant. The organic phase was a binary solution of D2EHPA and n-hexane, or D2EHPA and toluene, while the polar phase was a three component solution of metal salt, non-aqueous solvent and water. The extracted metal ions were Cr(III), Fe(III), Al, Cu, Ni, Co(II), Mg and Ag.

The extraction behaviors may be explained by the solvation ability of non-aqueous solvents, the decrease in distribution of the extractant and extract into the organic phase, and the interaction between the extractant and non-aqueous solvents due to the dissolution of non-aqueous solvents in the organic phase.     

THERMAL PERFORMANCE AND EVALUATION OF SIPERHEATED STEM DRYING SYSTEM USING SOLAR-ASSISTED ABSORPTION HEAT TRANSFORMER

ABSTRACT

This paper summarizes the main results of our study carried out under the priority-area research “Energy Conversion and Utilization with High Efficiency” supported by the grant-in-aid of scientific research from the Ministry of Education, Science and Culture of Japan. In the research we focused on applications of solar energy utilization for industrial drying systems. In this paper a new concept of a closed drying system with superheated steam provided from a temperature boosting type heat pump (absorption type heat transformer) was proposed. The heat transformer is driven directly by heat from a solar collector. The performance for different three drying periods and a number of factors affecting it were predicted by a computer simulation. Furthermore the heat and mass transfer characteristics of water evaporation into superheated steam stream by radiative and convective heating were indicated experimentally. It was concluded that the system would be useful for industries where high temperature (over 100°C) drying is required.