轻型门式刚架结构中关于稳定分析问题的探讨

针对现行《门式刚架轻型房屋钢结构技术规程》（CECS 102:2002）中关于稳定分析的部分条款,通过大量系统的有限元分析,指出上述条款中存在的问题,并提出改进的建议：1）对单跨门式刚架变截面柱计算长度系数的取值提出了修正,并扩充了取值范围;2）对带摇摆柱门式刚架变截面柱计算长度放大系数的公式提出了修正;3）对工字形截面构件腹板有效宽度系数的公式提出了修正;4）提出了新的风吸力下冷弯薄壁檩条稳定承载力计算公式.以上工作为《上海市轻型钢结构技术规程》的修订提供了理论依据.     

沼气生态农业模式综合评价

为了对沼气生态农业模式结构、功能和效益进行综合定量评价,该研究结合沼气生态农业模式自身的结构和功能特点,以生态农业模式评价指标体系为基础,选择了17个指标构建了沼气生态农业模式综合评价指标体系,应用层次均权法确定了沼气生态农业模式综合评价各指标的权重,在此基础上,运用综合指数法构建了沼气生态农业模式综合评价模型。并以宝鸡市2个典型沼气生态农业模式（陇县“沼气池—厕所—畜舍—菜（果、粮）”庭院生态农业模式和千阳县“桑—蚕—双孢蘑菇—畜舍—沼气池”生态农业模式）的研究数据对模型进行了验证,评价结果与实际情况吻合,表明该研究所提出的评价指标体系和模型具有适用性。     

真的是一剂良药？——评“鲶鱼效应”在应对图书馆职业懈怠中的作用

为应对图书馆界存在的职业懈怠,业界有人主张引进“鲶鱼效应”。然图书馆固有的铁饭碗制度、无生存之忧,领导的行政任命等现象却造成我国图书馆界形不成“鲶鱼效应”。图书馆可引进它的一些思想,改善目前存在的弊端。     

Effects of Particle Size and Processing Variables on the Properties of an Extruded Catfish Feed

Abstract

A catfish feed was extruded to determine how particle size, moisture content and screw speed affected the pellet durability, water stability index, and buoyancy. Increasing moisture content from 250 to 300 g/kg required less die pressure, specific mechanical energy and product temperature to produce durable pellets that were stable in water. Increasing screw speed from 200 to 400 rpm also lowered die pressure, due to a lower filled length of the extruder screw channels, but increased specific mechanical energy and product temperature; the resulting pellets had a lower apparent bulk density, but a higher degree of starch gelatinization and water stability index. Reducing particle size from 1200 to 700 m decreased die pressure and apparent bulk density, but increased product temperature, degree of starch gelatinization, pellet durability index and water stability index.     

Hilbert空间中的算子框架恒等式

利用算子理论的方法,讨论了Hilbert空间中算子框架的一些性质,得到几个关于算子框架的恒等式。     

利用有限酶解技术提高鲶鱼食用肉粉溶解度的研究

[目的]筛选出有限酶解鲶鱼肉蛋白的最佳用酶种类和酶解工艺条件,为鲶鱼食用肉粉的加工提供理论依据。[方法]以鲶鱼为原料,经预处理、采肉、漂洗、斩拌、有限酶解、打浆和干燥等工序加工而成鲶鱼食用肉粉。其中选择4种酶（风味蛋白酶、枯草杆菌中性蛋白酶、碱性蛋白酶和木瓜蛋白酶）作为水解用酶,分别在各酶最佳酶解条件下对鲶鱼肉糜进行水解,以鲶鱼肉粉的溶解度为评价指标。[结果]用中性蛋白酶作为有限酶解的酶类加工出的鲶鱼食用肉粉溶解度可达90%以上,最佳酶解工艺条件为：酶用量0.55%,酶解时间60 min,料水比1∶3（g∶g）。[结论]用中性蛋白酶作为有限酶解的酶类,加工出的鲶鱼食用肉粉溶解度最高,风味最佳。     

加快方格蔟推广步伐 进一步提高蚕茧质量

要提高认识,产政策,加强领导,认真实施,花大力气加快方格蔟推广步伐,进一步提高我省蚕茧质量。     

Effect of varying density and water level on the spawning response of African catfish Clarias gariepinus: Implications for seed production

The development of a reliable methodology for spawning of African catfish, Clarias gariepinus without the use of hormone injections would greatly improve the prospects of aquaculture in Africa. Earlier work has shown that it is possible to produce C. gariepinus fingerlings by subjecting the broodfish to a physical stress of reduced water depth and/or increased temperature. The hypothesis that C. gariepinus could be induced to spawn through a combined physical stress of lowered water level and increased stocking density was tested in concrete tanks. Three water levels (25, 50 and 75 cm) and three stocking densities (2, 4 and 6 pairs of broodfish at a 1:1 sex ratio in each hapa) were tested. Water depth in the tanks and brood fish density in the hapas affected spawning success. The percentage of spawning females was significantly higher when broodfish were stocked at 2 and 4 pairs in each hapa at water levels of 25 cm or 50 cm. There was no significant difference in spawning response between the 25 and 50 cm depths while a significant difference was seen between the 75 cm and both 25 and 50 cm depths. The results indicate optimum levels and densities for enhancing spawning success in C. gariepinus.     

Evaluation of Diquat as a Potential Algicide for Controlling the Musty-Odor-Producing Cyanobacterium,Oscillatoria perornata,in Catfish Aquaculture Ponds

ABSTRACT

The synthetic herbicide diquat was applied to a catfish aquaculture pond containing a heavy bloom of the cyanobacterium Oscillatoria perornata(a major contributor to musty off-flavor in farm-raised catfish) in order to determine the effectiveness of diquat as a selective algicide to prevent musty off-flavor in cultured catfish. Levels of the musty-odor compound 2-methylisoborneol (MIB) and numbers of O. perornata were monitored. Results indicate that diquat is not useful as an algicide for controlling O. perornata in catfish aquaculture ponds, despite its usefulness in controlling other aquatic weeds.     

Influence of Washing and Cold Storage on Lipid and Protein Oxidation in Catfish (Clarias lazera) Surimi

ABSTRACT

Lipid and protein oxidation in catfish (Clarias lazera) surimi during processing and storage were assessed. Catfish surimi were washed in deionized water: M0 (no washing step), M1 (one washing step), and M2 (two washing steps). Lipid, protein, water, and iron contents were determined. M0, M1, and M2 were stored for 0, 1, 4, 7, or 10 days at 4 ± 1°C; at each time point, samples were removed for analyses. Lipid oxidation was assessed by measuring malondialdehyde content. Protein oxidation was assessed by measuring protein solubility and protein sulfhydryl and carbonyl group contents. Based on the results, lipid content, L* and a* (color parameters), and fatty acid content in M1 and M2 were significantly reduced. Lipid oxidation development was faster in M1, and the ranking was as follows: M1 > M2 > M0, with M0 being significantly less oxidized than M1. Increasing the number of washes increased protein oxidation, and the ranking was follows: M2 > M1 > M0. Altogether, lipid and protein oxidation and physicochemical changes occurred simultaneously to different degrees in surimi during various processing and storage conditions.