ZrO_2与40Cr钢钎焊中的缓冲层

本试验研究了ＺｒＯ２与４０Ｃｒ钢在加入缓冲层前后的钎焊连接，结果表明：插入缓冲层Ｃｕ和Ｔｉ可以提高接头强度。对每一种缓冲层，存在一最佳厚度，对应的钎焊强度最大。此最佳厚度对Ｃｕ为０．４ｍｍ左右，对Ｔｉ为１ｍｍ左右。作者认为这是由缓冲层的力学性能和热膨胀系数对残余应力释放产生的两种相反影响而造成的。钎焊时，缓冲层Ｃｕ和Ｔｉ向钎料中均有程度不同的溶解，但不影响钎料对ＺｒＯ２的浸润和反应结合。ＺｒＯ２－４０Ｃｒ钢连接的所有接头均断在陶瓷的近缝区，其断裂方式有三种。     

兴安岭山地低信噪比地震资料处理技术分析

大、小兴安岭山地地表大多被火山岩、火山岩风化形成的残余物和腐植土所覆盖，地震资料中普遍存在较强的折射波和多次折射波，资料的信噪比很低；此外，该区低、降速层厚度和速度横向变化剧烈，静校正问题突出，为此，开展了有针对性的处理方法研究。针对山地地表起伏大的特点，采用了浮动基准面方法；针对低、降速层厚度和速度横向变化剧烈的特点，采用了折射静校正和微测井静校正相结合的方法；针对折射波强的特点，采用了t—x域叠前相干压制方法；针对叠加剖面随机噪声严重的特点，采用了f—x域随机噪声衰减方法。实际资料处理表明，采用上述处理手段，提高了资料的信噪比，增强了同相轴的连续性，突出了反射波组特征。     

裂解碳五选择性加氢研究

将裂解C5馏分资源经选择性加氢、醚化,合成了高辛烷值汽油调和组分。为满足醚化催化剂的要求,进行了蒸汽裂解C5双烯烃选择性加氢工艺研究,对裂解C5双烯烃选择性加氢催化剂进行了评价,考察了反应压力、空速、反应温度、氢烯摩尔比对双烯烃选择性加氢的影响,得出适宜工艺条件为:反应压力0.5～1.5 MPa,温度45～80℃,空速10～2．0 h-1 ,氢烯摩尔比大于1.1。     

Microring resonator channel dropping filters

Microring resonators side coupled to signal waveguides provide compact, narrow band, and large free spectral range optical channel dropping filters. Higher order filters with improved passband characteristics and larger out-of-band signal rejection are realized through the coupling of multiple rings. The analysis of these devices is approached by the novel method of coupling of modes in time. The response of filters comprised of an arbitrarily large dumber of resonators may be written down by inspection, as a continued fraction. This approach simplifies both the analysis and filter synthesis aspects of these devices     

非线性时间序列数据中的关联维提取

本文将混沌方法引入具有非线性时间序列的降雨量分析。首先对有关混沌及关联维的概念作简单介绍,在确定降雨量数据具有混沌特征后,对其进行关联维提取,得到颇具意义的结果。     

用生态模式建设城市河流防护工程刍议

在城市河流防护工程实践中,传统砌石、混凝土等护砌方式在达到一定的功能目的的同时,产生了许多消极后果。针对用生态模式建设城市河流防护工程,恢复并保护自然水环境进行研究与探讨,可为山东三大工程提供有关技术的可行性与技术支持,做好科技服务。     

Results of a 90-day toxicity study on 1,2,3- and 1,1,2-trichloropropane administered via the drinking water

Trichloropropanes have been identified as environmental contaminants in sediments of the Great Lakes region of North America. Since these chemicals had the potential to find their way into drinking water, a 90-day feeding study was carried out in order to determine their subchronic toxicity. Groups of 10 male and 10 female weanling Sprague-Dawley rats were supplied drinking water ad libitum, containing 1,2,3- or 1,1,2-trichloropropane at concentrations of 1, 10, 100 or 1000 mg/L for 13 weeks. Emulphor (0.5%) was used to solubilize the chemicals. At the end of the study, the animals were killed and examined for gross and microscopic changes. Heart, liver, brain, kidney and spleen were excised and weighed. Blood was collected and subjected to a comprehensive hematological analysis. Serum was collected and profiled for changes in 12 biochemical parameters and a portion of liver was used to determine mixed function oxidase activity. Although three animals died during the study, their deaths could not be related to treatment. Decreased growth rate was observed in both sexes of the group receiving 1000 mg/L 1,2,3-trichloropropane. There was an increase in liver, kidney and brain weights (relative to body weight) in rats of both sexes fed 1000 mg/L 1,2,3-trichloropropane. Fatty livers were observed in some of the treated animals but a clear dose-relationship was not evident. An elevation in serum cholesterol was observed in female rats fed the highest dose of 1,2,3-trichloropropane. This chemical also induced hepatic aminopyrine demethylase and aniline hydroxylase activities in male rats at the highest dose. Administration of both isomers produced only mild histological changes in the liver, thyroid and kidney of rats at the highest dose. The changes in the liver consisted of an increase in cytoplasmic eosinophilia in the periportal area together with vesiculation of biliary epithelial nuclei. Morphological changes were characterized by increased anisokaryosis in the proximal epithelium and occasional pyknosis associated with the accumulation of large eosinophilic inclusions. Changes in the thyroid consisted of a mild reduction in follicular size associated with an increased epithelial height. In general, these changes were more severe in the males than females, but were still mild overall. It was concluded that the no-effect level for both chemicals was 100 mg/L (15–20 mg/kg bw/day) and based on effects on growth rate and other changes, the 1,2,3- isomer was judged to be slightly more toxic than the 1,1,2- isomer.     

Growth temperature dependence of low-noise MESFET in molecular-beam epitaxy

The substrate growth temperature dependence of electrical properties for a low-noise MESFET fabricated on MBE-grown material has been demonstrated. The optimum noise figure and its associated gain were attributed to the higher epilayer quality and mobility at a growth temperature of 650°C between temperatures of 550°C and 700°C.     

广义Foster定理

利用Ｍａｘｗｅｌｌ方程组导出了适用于有耗网络的广义Ｆｏｓｔｅｒ定理，得到了一些有关电抗斜率以及Ｑ值的有用公式及结论。