Structural significance of the alkyl substituent at the C-4 of (+)-trans-verbenyl acetate in sex pheromonal activity of the American cockroach

The significance of the alkyl group at the C-4 of (+)-trans-verbenyl acetate, which is the sex pheromone mimic of the American cockroach, was investigated. Seven alcohols possessing an ethyl, propyl, or dimethyl group at this position of the 6,6-dimethylbicyclo[3.1.1]heptane skeleton were synthesized and evaluated by behavioral assay. All of the alcohols were inactive, while three of four acetates of the 2-alcohols induced sexual behavior in male cockroaches at the 0.02 or 0.5 mg dosage level, either of which is many orders of magnitude higher than the threshold level of the natural sex pheromones (10^–8 mg). Among the acetates, the compounds with a methyl group or an -oriented ethyl group at C-4 showed the highest activity. The results are discussed in terms of spatial requirements of the molecules for interactions with the receptor.Studies on the sex pheromone mimic of the American cockroach, (+)-trans-verbenyl acetate. Part VIII. For Part VII, seeComp. Biochem. Physiol.,70A: 229–234 (1981).     

基于PSoC的数字电压表设计

采用Cypress公司生产的PSoC3芯片实现了一个数字电压表的设计。设计使用芯片集成的A/D转换模块完成模数转换,并且通过程序调用读取相应的数字量及芯片强大的LCD显示模块,将转换后的数字量和相应的模拟量显示出来。本设计具有硬件设计简单、软件设计图形化、可以充分利用PSoC提供的固件元件的优点。     

网络通讯在高杆灯监控系统中的应用

针对城市中高杆灯监控系统,设计了一套基于C/S与GPRS的监控系统软件。根据GPRS数据通讯的特点,确定传输帧数据格式、制定了相应的传输协议。将完成端口通信技术应用到服务器软件的网络通信模块设计中,实现高效的系统网络性能。测试表明,所设计的监控系统软件具有较高的数据处理能力,在实际运行中也表现出良好的性能。     

基于TD-SCDMA的视频码率动态调整策略

通过对基于TD-SCDMA无线视频监控系统的研究,提出了一种无线传输环境下的视频码率动态调整策略。针对TD-SCDMA信道低带宽、高时延、高误码率的特征,该策略可以根据实时网络环境动态调整码率,以便视频数据能够适应其传输。经过TD-SCDMA无线视频系统的实际应用,证明本策略能够有效解决由于TD-SCDMA信道特征给视频传输带来的不利影响。     

氮化硅基陶瓷连接技术的研究进展

陶瓷连接技术是结构陶瓷实用化的有效手段，焊料成分对连接体的性能具有决定性作用。本文主要从焊料成分选择的角度，总结了氮化硅基陶瓷连接技术的发展现状；并重点讨论了陶瓷／玻璃复合焊料在β-Sialon陶瓷连接中的应用。     

Influence of Pt Loading on Al2O3 for the Low Temperature Combustion of Methanol with and Without a Trace Amount of Ammonia

Pt/Al₂O₃ catalysts with platinum contents of 0.1, 1.0 and 3.0 wt% were used for the low temperature combustion of methanol in the absence and the respective presence of a trace amount of ammonia. It is observed that ammonia inhibits the combustion of methanol, which is due to competition between methanol and ammonia for the same sites. For a fixed space velocity and without ammonia in the gas, the performances of the catalysts increase up to a Pt loading of 1.0 wt%. In the presence of ammonia, however, no upper limit of performance is observed with increased Pt content. The results are discussed in terms of both Pt–support interface and the Pt surface being active.     

基于CAD/CAE/CAM/RP的复杂陶瓷产品快速制造技术

针对目前手工方式的卫生洁具等复杂陶瓷产品的研发过程,借鉴CAD/CAE/CAM/RP技术在其它制造行业中应用的成功经验,将这些先进制造技术应用于卫生洁具等复杂陶瓷产品的研发中;CAD用于设计产品和模具的模型,CAE用于模拟洁具冲水过程和分析冲水性能,RP用于制作洁具产品的原型,CAM用于加工试用石膏工作模具。就这些技术的应用提出了两种主要方案,并分析了各自的特点。经过实际应用表明:先进制造技术的应用能大大缩短产品研发周期、提高产品质量、降低开发成本。     

炭/炭复合材料制造硅晶体生长坩埚初探

多晶硅用直拉法(CZ)或磁场直拉法(MCZ)拉制成单晶硅棒。晶体生长炉热场零件中的石墨发热体、坩埚等在机械应力和热应力的综合作用下发生变形或损坏造成失效,更换频繁。选用纯度高的炭纤维制成待制件的多孔坯体,经过增密、纯化处理制成炭／炭复合材料坩埚。试制的两体12″炭／炭复合材料坩埚进行了工业性试验。炭／炭复合材料机械强度高、耐热冲击性能和化学稳定性好,其使用寿命大大高于高纯石墨坩埚。两体的连接止口的氧化侵蚀限制了坩埚的使用寿命。单晶硅设备的大型化、炭／炭复合材料势必成为晶体生长炉热场零件的必选材料。     

逆反应烧结制备铝电解槽用氮化硅-碳化硅复合材料

采用常规的反应烧结工艺制作铝电解槽侧壁材料用Si3N4／SiC时存在不足，为此，提出应用逆反应烧结工艺进行生产性试验的设想。在制备Si3N4／SiC复合材料时，常规反应烧结是以Si和SiC为原料经氮化烧结；逆反应烧结是以Si3N4和SiC为原料，首先使Si3N4反向反应生成活性氧化物后进行烧结。结果表明：该工艺特点是新生的Si2N2O或SiO2进行活性烧结；制品具有良好的物理和化学性能。制品结构紧密，新生氧化物或亚氧化物紧密地充填在Si3N4和SiC颗粒间界，新工艺制备的砖的抗冰晶石熔体侵蚀的性能优于常规工艺烧成砖，是铝电解槽侧壁的良好材料。     

Synthesis and electrochemical characteristics of Al2O3-coated LiNi1/3Co1/3Mn1/3O2 cathode materials for lithium ion batteries

LiNi_1/3Co_1/3Mn_1/3O₂ cathode materials have been coated with Al₂O₃ nano-particles using sol-gel processing to improve its electrochemical properties. The X-ray diffraction (XRD) pattern of the as-prepared Al₂O₃ nano-particles was indexed to the cubic structure of the γ-Al₂O₃ phase and had an average size of ∼4 nm. The XRD showed that the structure of LiNi_1/3Co_1/3Mn_1/3O₂ was not affected by the Al₂O₃ coating. However, the Al₂O₃ coatings on LiNi_1/3Co_1/3Mn_1/3O₂ improved the cyclic life performance and rate capability without decreasing its initial discharge capacity. These electrochemical properties were also compared with those of LiAlO₂-coated LiNi_1/3Co_1/3Mn_1/3O₂ cathode material. The electrochemical impedance spectroscopy (EIS) was studied to understand the enhanced electrochemical properties of the Al₂O₃-coated LiNi_1/3Co_1/3Mn_1/3O₂ compared to uncoated LiNi_1/3Co_1/3Mn_1/3O₂.