内蒙古鄂托克前旗畜牧业生产合理布局初探

对鄂托克前旗畜牧业生产环境和生产现状进行了综合分析,并计算了气侯生产潜力和草地载畜量,根据自然条件、生产现状和牲畜生态地理分布特征,把鄂托克前旗分为4个牧业经济区,并阐述了各区的优化途径。     

二次损失下位置参数的最优不变估计的非容许性及其改进估计

本文应用Ｂｒｏｗｎ方法，找出一类随机变量（密度形为ｆ（ｘ一θ），三阶矩存在）位置参数最优不变估计非容许的充分条件。进而证明其最优不变估计是非容许的，并给出一族改进估计。作为特例，使多维正态分布（ｐ≥３）的位置参数通常估计的非容许性又一次得到证明。     

北江飞来峡工程纵向围堰渗流计算

北江飞来峡工程纵向围堰体及堰基的组成复杂。本文采用了有限元解拉普拉斯方程的方法解绘出不同上下游水位和高喷板墙不同渗流系数各种组合的等势线，并用当量渗流系数法计算了二十种不同上下游水位和堰体、堰基渗流系数组合的单宽渗流量，以及用局部流网法解出两组逸出比降和逸出流速。最后得出可供工程单位参考的结论和理论规律。     

MRAS的工程设计方法及应用

本文提出一种结构简单、易于工程实现的信号综合自适应MRAS的超稳定性简化设计方法。文中从理论与实践两方面论证了该方法的正确性和可行性,给出该设计方法依据的引理、数学证明以及应用于小功率自适应调速系统的实验结果。使用本文引理设计的小功率自适应调速系统的动态、静态性能均获得满意结果。本文对于推广MRAS的工程应用具有重要参考价值。     

合成增香剂乳酸乙酯新方法(Ⅱ)

本文报道一种金属卤化物酸性催化剂MXn,用于催化合成增香剂乳酸乙酯。反应温度68～78℃,酯化时间2～2.5小时,产率65～71％,含量≥99％。     

Comparison of distribution and habitat characteristics between an endemic and a wide-ranging cryptic species of Peromyscus on the Baja California Peninsula

Peromyscus eva and Peromyscus fraterculus are 2 morphologically similar species of the Peromyscus eremicus group occurring on the Baja California Peninsula. Due to the similarity between these 2 species, their ranges have been greatly confused; consequently, the specific habitat characteristics for each group are not well known. The goal of this study was to assess distribution ranges and characteristics of preferred habitats for P. eva and P. fraterculus in more detail. We identified taxonomy of individuals by evaluating genetic patterns produced by restriction fragment length polymorphisms (RFLPs). We evaluated the banding pattern generated by Alu I and Bam HI restriction enzymes in an 850-bp cytochrome b fragment. Consistent differences in number and size of fragments allowed for discrimination of individuals to species. The heterogeneity and evenness indexes showed that the microhabitat of P. fraterculus contained less-diverse soil types and is more homogeneous than the microhabitat of P. eva. In the state of Baja California Sur, P. eva occurs exclusively in the flat areas along the Pacific coast from the Vizcaino Desert to the south, including Margarita Island, with one small population in the Loreto area adjacent to Carmen Island. The habitats occupied by P. eva were heterogeneous (areas with friable, soft sandy soil and a low percentage of small stones). Peromyscus fraterculus occurs mostly in Baja California Norte, with some populations distributed in Baja California Sur, particularly in the western areas of the Vizcaino Desert along the mountain range, in the gulf side of the peninsula south of the city of La Paz, and in a small area on the eastern side of Sierra de Las Cruces. This species was mostly found on hard soil with high medium-size stone content.     

Cytogenetic studies of Hynobiidae (Urodela). XIV. Analysis of the chromosome of a Chinese salamander, Batrachuperus pinchonii (David)

The chromosome number of a Chinese salamander, Batrachuperus pinchonii, was re-examined. Adults and embryonic specimens had a diploid number of 66, with 33 bivalents during meiosis, in contrast to previous reported results. Furthermore, when C-banding analysis was performed with embryos, chromosomes with banding patterns homoeologous to those of Salamandrella keyserlingii and Hynobius species were found. It appears, therefore, that Batrachuperus, Salamandrella and Hynobius might be derived from a common ancestral species in eastern Asia. Received 22 August 1997; received after revision 14 October 1997; accepted 20 November 1997     

微乳液介质中5''-硝基水杨基荧光酮光度法测定钼

研究了在阳离子型微乳液(CTMAB-正丁醇-环己烷-水)介质中,钼()-5’-硝基水杨基荧光酮(5'-NSF)的显色反应。结果表明,在0.24~0.60 mol.L-1HCl溶液中,钼与5'-NSF形成1∶2的橙红色稳定络合物,其最大吸收波长为529 nm,Δλ=60 nm,表观摩尔吸光系数ε529=6.55×105mol-1.cm-1,钼的浓度在0~0.20 mg/L范围内符合比尔定律。此方法灵敏度高,用于样品中微量钼的测定,结果令人满意。     

Adenylate cyclase in the developing rat cerebral cortex and olfactory bulb

Activities of adenylate cyclase, measured either in the absence or presence of sodium fluoride and Triton X-100, are determined in cerebral cortex and olfactory bulb homogenate of rats of 1 to 35 days of postnatal age. Differences in properties of the enzyme in the 2 structures are demonstrated.