Abstract:In this peper, the theoratical calculation of electric parameters forelectric fish screen (EFS) of divider-type is presented acoording to the principles ofequivalent circuit, axis-mirror image method and electromagnetics respectively. Theirconstraint conditions of simplification and approximation are also analyzed. The analy-sis shows that the theoratical calculation formula are applicable to different situation,that is, (1) the equivalent circuit method is approximately suitable to comparativelylarge aquatic areas, in deepwater layers or center part of the blocking section (calledsituation 1); (2) the axis-mirror image method is accurately suitable to the mirror planeperpendicular or parallel to the line of the electrode absolutely (called situation 2), otherwise, it is mistaken and senseless; (3) the electromagnetics method is accuratelyuseful to situation 1. The calculated examples show that: (1) The error between the equivalent circuit method and the electromagneticsmethod is less than 5%, and in other words, the error can be neglected in engineeringdesign and analysis. (2) The error between the electromagnetics method and the axis-mirror imagemethod is significant when the electrode line is close to the image plane, and unsigni-ficant when the distance from the electrode line to the image plane is larger than 5d. In practice, the EFS of divider-type is usually designed and located on the spillwayof reservoir. The dam and the bank of spillway are certainly angular to the electrodeline in oder to improve the efficiency of stopping fish escaping. The electric parametersare thus calculated by both the equivalent circuit method and the electromagneticsmethod, but the axis-mirror image method.

Abstract:本文采用以产品色香味和口感为主的感官质量检定方法,对4种新开发的鲐和远东拟沙丁鱼深加工产品,在10～30℃常温和5℃,-10℃低温下进行了质量和保藏期的测定。结果表明:除30℃保藏的鱼肉火腿外,所有产品都达到了出厂规定的保藏期限,包括5℃和-10℃保藏的维也纳香肠和口乐开所达到的保质期限,产品的加工质量是良好的;明确了这些产品保藏中的质量变化特点是以占总感官质量变化74.5%～96.8%的色香味口感为主的原有品质下降,以及比较轻微的脂肪酸败;这种以色香味口感为主的质量下降程度的大小,取决于从-10℃至30℃范围保藏温度的高低;因此,防止这类密封包装和加热杀菌的常温流通产品质量下降的有效途径是采取适当的低温保藏,其中包括至少在夏季避免长时间的常温流通以及尽可能地全部在适当低温下流通,从而使这类深加工产品成为具有保持原有良好风味不变的-定保质期限和更好市场竞争力的商品。

Abstract:本文报道了杭州湾畔中国对虾幼虾中间培育池的水化学状况。1993年4～5月全培育期内池水有效氮(N_t)含量丰富,N_t平均为1.47mg/l,其中氨氮占59%,亚硝酸氮占1%,硝酸氮占40%。有效磷基本未检出。化学耗氧量(COD_(Mn))11.9mg/l,可溶性有机物耗氧量占86%以上。pH为9.15。溶解氧收大于支,水呼吸耗氧平均约占虾池总耗氧量61%,底质耗氧约占31%,虾呼吸耗氧约占8%。幼虾瞬时耗氧速率与溶氧量、体长和体重间存有良好相关性。据观测结果与多年生产状况,认为河口沿岸幼虾中间培育池放苗密度在225万尾/公顷内,采取在放黄时约27cm水位基础上,每隔2～3天添加10～15cm水量,最终水位达1.00m的管理方式较为合理。

Abstract:The test of nutritional requirement of Penaeus chinensis for dietarycalcium, phosphorus, magnesium, potassium and iron was designed with orthogonalmethod(L_(16)4~5). Body weight of the tested P. chinensis was about 8g. Duration of the testwas 48 days. Growth, moisture and ash of P. chinensis were determined. The ratio ofcrust to body weight was calculated. The diet with 2.2% calcium. 0.91% phosphorus, 0.11% magnesium, 0.32% potassium and without iron were optimum for the fastestgrowth, minimum ash and the lowest ratio of crust to body weight. The effect of dietarylevels of these inorganic elements on P. chinensis moisture was not significant. Compa-rison between our results and Li Ai-jie's report indicated that nutritional requirementof P. chinensis for dietary inorganic elements differ with their growth.

Abstract:本课题研究了鲐鱼的不同鲜度的原料、真空包装与普通包装、-10℃与-18℃保藏温度、去头脏的鲜制品与腌制品等不同的加工保藏条件对制品的质量变化和保藏期限的影响。结果表明:在-10℃、-18℃保藏温度下,影响和决定鲐鱼制品质量变化和保藏期限的主要因素是脂肪的氧化酸败。各不同加工保藏条件中对制品质量和保藏期限影响最大的是制品的包装、原料鲜度和保藏温度。普通包装和低鲜度原料制品的保藏期低于2～3个月,POV值高达100～200meq/kg。真空包装、高鲜度原料和保藏在-18℃的保藏期最长可达到6个月以上,其POV值低于40meq/kg。其他具有不同包装方法和原料鲜度产品的保藏期则介于2～6个月之间。鲜制品与腌制品无明显影响。

Abstract:The acute toxic effect of malachite green, furazolidon, mixture ofcopper sulphate and ferrous sulphate (ratio 5:2), common table salt, methylene blue andheavy metals such as Hg, Cd, Cu and Zn on larva of crucian carp, Carassius auratusgibelio were determined with static bioassay test. The experimental results showed thatthe safe concentrations of 4 kinds of chemicals to fish disease (except methylend blue)were 0.012, 32.900, 0.680 and 870 ppm, respectively. The safe concentrations of 4 kindsof heavy metals(Hg, Cd, Cu and Zn) were 0.0006, 0.0113. 0.0270 and 0.0950 ppm,respectively.

Abstract:On the basis of the texture profile developed by Szczensniak(1963), therating criteria for sensory analysis was preliminarily set up to quantitatively evaluatemechanical characteristics of foods produced in this country. The characteristics containhardness, brittleness, chewiness, viscosity, springiness and gumminess, and some of them were verified by the instrumental methods. The experimental results showed the closecorrelation between the sensory evaluation and objective measurements.

Abstract:This paper aims at studying the microcomputer control for the refri-gerating installation of middle or small size. The schematic diagram of software de-sign, the principle of connection line for input and output interface, the microcomputercontrol system for the installation and the designs of software and hardware for auto-defrost system of energy-save type were studied in the paper. The microcomputer controlhas the features of small dimension, high controllability, good stability and reliability,low cost, etc, and is appropriate to the self-test and real-time control of the refrigeratinginstallation in the process of running. Hence, it will help commercialize the energysave defrosting system for the refrigerating installation by microcomputer control.

Abstract:This review summarises the recent advancement of fish biotechnologyin China. By means of temperature shock and hydrostatic pressure, Chinese scientistsobtained six autopolyploid and two allopolyploid fishes. Combining the inducedgynogenesis with the technique of sex reversal, Chinese scientists developed a method ofestablishing fish inbred lines. Several nucleo-cytoplasmic hybrids were obtained bycombination of nuclei and cytoplasms from different species, genera and subfamilies. Anuclear transplanted fish was also obtained from the nucleus of short-term culturedkidney cell of crucian carp, which suggested the nucleus of fish somatic cell still retainedtotiptency. Electric field and laser microbeam were employed to induce the fusionbetween fish unfertilized eggs and blastula cells and between fertilized eggs respectively,fry or larvae were obtained in these experiments. To produce fast-growing transgenicfish, Chinese scientists made a serial investigations on integration, transcription, ex-pression and biological effects of human growth hormone gene in fish. The method ofgene transfer employed by Chinese scientists included microinjection, electroporationand exposure of spermatozoa to DNA followed by insemination. So far, Chinese scien-tists have cloned seven fish genes, i.e., growth hormone genes of Cyprinus carpio,Ctenopyharyngodon idellus and Oncorhynchus keta, beta-actin genes of C. carpio and C.idellus, prolactin cDNA of Oncorhynchus tschawytscha and antifreeze peptide cDNA ofPseudopleuronectes yokohamae.

Abstract:256 sets of brood fish of grass carp, silver carp, bighead and bluntsnout bream were induced to spawn in the autumn of 1991, and up to 50.4 million frywere obtained. The mean spawning rate, fertilizing rate and hatching rate were 78.2%,71.9% and 75.4% respectively. The fry from autumn propagation could breed intolarger fingerling in the same year (over 10 cm for bighead and silver carp, over 8 cm for grass carp and blunt snout bream). The viability of the fingerling was 37.2%.Compared with the results for once a year spring propagation, the spawning, fertilizing,and hatching rate were generally not affected. Only the egg number decreased 6.8%-9.6%. There are no significant differences in size and weight of eggs and length offry. In grass carp, silver carp and bighead the oocytes develop asynchronously. Theimmature oocytes in the ovary of the brood fish after the spring propagation coulddevelop to full mature under strengthened culture for about 60 days.