同步沉淀除磷在污水生物处理中的应用

在同步沉淀工艺的基础上,综述了同步沉淀在不同的污水生物处理工艺中的除磷效果、化学试剂用量的控制、除磷过程模拟的研究进展,并重点讨论了同步沉淀中的化学试剂对生物处理系统性能的影响.最后,展望了同步沉淀在污水生物处理中的应用前景和研究方向.     

Low linolenate and commercial soybean oils diminish serum HDL cholesterol in young free-living adult females

OBJECTIVE: A mutant soybean line (A16) low in linolenic acid content (2% of oil by weight) was developed to increase oil oxidative stability. It was unknown whether serum lipid and lipoprotein concentrations in humans would be affected should A16 soybean oil (A16 oil) replace commercial soybean oil in diets. This study was conducted to examine the hypothesis that in free-living normolipidemic women, the consumption of A16 oil at approximately 10% of energy intake (en%) would not affect serum lipids and lipoproteins differently than would the consumption of the same amount of a commercial soybean oil with 7% of linolenic acid content. DESIGN: Fifteen free-living female college students consumed the soybean oil daily with regular meals for 9 weeks in different orders, with each test oil being eaten for 3 weeks. During the study, 13 en% was provided by each test oil and a total of 35 en% was from dietary fat. Serum concentrations of total cholesterol, high-density lipoprotein cholesterol (HDL cholesterol), low-density lipoprotein cholesterol (LDL cholesterol) and triacylglycerides (TAG) were measured. Serum total fatty acid patterns were analyzed as well. RESULTS: Each of the three test oils decreased serum total cholesterol, LDL cholesterol and TAG concentrations from the baseline values. The feeding of A16 and commercial soybean oils decreased serum HDL cholesterol significantly compared with coconut oil (p < 0.05). Dietary inclusion of coconut oil increased serum myristic acid significantly more than did either soybean oil (p < 0.01). Serum arachidonic acid concentrations were significantly greater with A16 consumption than with commercial soybean oil consumption (p < 0.001). CONCLUSION: A16 and commercial soybean oils both diminished serum HDL cholesterol. Although the fatty acid composition differed between the two soybean oils, A16 oil and commercial oil had similar effects on serum concentrations of lipoproteins and lipids. With increased oxidative stability, A16 oil is a good alternative to commercial soybean oil.     

轧机主传动直流电动机通风冷却系统的设计与应用

通过实例简述了扎机主传动直流电动机通风冷却系统的风机选择原则,方法及其风机房,风机基础和通风管略的设计与应用。     

The binding motifs for Ac transposase are absolutely required for excision of Ds1 in maize

A reverse genetic system for studying excision of the transposable element Ds1 in maize plants has been established previously. In this system, the Ds1 element, as part of the genome of maize streak virus (MSV), is introduced into maize plants via agroinfection. In the presence of the Ac element, excision of Ds1 from the MSV genome results in the appearance of viral symptoms on the maize plants. Here, we used this system to study DNA sequences required in cis for excision of Ds1. The Ds1 element contains the Ac transposase binding motif AAACGG in only one of its subterminal regions (defined here as the 5' subterminal region). We showed that mutation of these motifs abolished completely the excision capacity of Ds1. This is the first direct demonstration that the transposase binding motifs are essential for excision. Mutagenesis with oligonucleotide insertions in the other (3') subterminal region resulted in elements with either a reduced or an increased excision efficiency, indicating that this subterminal region also has an important function.     

高超声速巡航飞行器在线航迹规划方法

为解决弹载计算机内存小、运算速度慢与在线航迹规划内存需求大、实时性要求高之间的矛盾,给出了基于高速DSP的高超声速飞行器在线航迹规划方案。介绍了一种实时航迹规划策略,设计了基于ADSP21364的在线航迹规划器,提出了改进的稀疏A*算法,最后进行了地面模拟飞行试验。仿真结果表明,设计的规划策略和规划算法能够在现有硬件基础上避开各种新威胁,生成一条当前最优/次优的航迹,并且规划稳定性好、成功率高。     

灰色人工神经网络人口总量预测模型及应用

针对单一指标进行人口总量预测精度不高的问题,基于灰色系统理论和人工神经网络理论,用1990年至2004年中国人口总量序列建立并训练一个多指标的灰色人工神经网络人口总量预测模型。对2005年至2007年的人口总量进行检验性预测,结果表明灰色人工神经网络模型大大提高了预测精度。     

NKChemSQL——针对MySQL的化学信息学扩展

化学数据库是进行化学信息学研究的重要资源,分子属性与指纹计算、分子结构格式转换、分子相似度匹配、精确匹配和子结构匹配以及分子结构图片导出等,都是必需的基本服务内容。应用广泛的数据库系统MySQL却缺乏这些功能,难以满足化学信息处理、网站开发等开发的需求。NKChemSQL是自行编制的MySQL扩展库,通过对开源软件OpenBabel的功能进行包装,以SQL语言的格式完成相应操作。NKChemSQL具有良好的运行表现,经过对含26万余条分子结构信息的NCI数据库进行的测试,全结构匹配只需不到1秒而子结构匹配达300个结构/秒,相似度匹配则达1万个结构/秒。NKChemSQL为开发化学信息学软件和网站提供了非常便利的新方式。     

壳聚糖负载稀土化合物催化环氧乙烷与环氧丙烷共聚合反应研究

研究以壳聚糖(Cs)作为高分子金属催化剂载体,制得负载稀土金属化合物的高分子金属催化剂,应用于环氧乙烷(BO)和环氧丙烷(PO)的共聚合反应.研究发现以三异丁基铝(Al(i-Bu)3)为助催化剂,乙酰丙酮(Acac)为第三组分时,该体系的催化活性高达192 kg*copolymer/mol*Y,比非负载型稀土催化体系活性提高1个数量级以上.环氧乙烷和环氧丙烷的竞聚率r 1(EO)、r 2(PO)分别为2.75±0.02和0.55±0.01;并用13C-NMR谱和DSC谱对共聚物结构进行了表征.     

添加物对Fe_2O_3超微粒的稳定作用

粒子的尺寸直接关系着气敏元件性能的好坏．为了防止Ｆｅ２Ｏ３超微粒在气敏元件烧结过程中长大，我们在纯Ｆｅ２Ｏ３中掺入５ｍｏｌ％碱土金属离子，利用ＸＲＤ和ＴＥＭ系统研究了掺杂物对Ｆｅ２Ｏ３超微粒子的稳定作用，并对由掺杂引起的Ｆｅ２Ｏ３电学性质的变化作了初步探讨．     

Analysis of the drude model in metallic films

A method, believed to be new, to simulate Drude parameters for collective oscillation of the free carriers in metallic films is proposed. Plasma resonance frequency and relaxation were simulated simultaneously from both the real and the imaginary parts of the dielectric function of a metallic film after consideration of their correlation in the Drude model. As examples, the contributions of the electrons in Ag films and of the free carriers in metallic silicide, NbSi(2) and TaSi(2), films have been studied.