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Plagiognathops microlepis Bleeker,an economic freshwater fish (Xenocyprininae,Cyprinidae) widely distributed in China,is a favorite with our broad masses,but itsnatural population is not large and the yield of this fish is low in many waters.As a result of our experimentation and research,now we can successfully conductartificial propagation and culture of this fish on a large scale.We have already stoc-ked a reservoir with a large number of its sizable fingerlings,in anticipation of inc-reasing yield in the... Plagiognathops microlepis Bleeker,an economic freshwater fish (Xenocyprininae,Cyprinidae) widely distributed in China,is a favorite with our broad masses,but itsnatural population is not large and the yield of this fish is low in many waters.As a result of our experimentation and research,now we can successfully conductartificial propagation and culture of this fish on a large scale.We have already stoc-ked a reservoir with a large number of its sizable fingerlings,in anticipation of inc-reasing yield in the coming years.For pond-farming,it has been demonstrated that the participation of Plagiog-nathops in polyculture with the team of“domestic”carps does not interfere with thenormal growth of the latter,and the total yield of a pond is actually increased byabout 10%.The fish is easy to catch (by seining);this makes it a desirable objectfor the practice of recurrent stocking and“skimming”within a year in ponds in-tended for bumper yield.The juveniles as well as the adults of Plagiognathops feed on humus,bottomdetritus and benthic algae,which are not much utilized by the traditional“domestic”fishes.Growth rate of Plagiognathops is rather high during the first two years of life:young fish 6 months of age weigh about 100—150 g,those of 18 months old,above250 g (450 g for the largest specimen);the average weight of 2-year-old individuals is500 g,a size ready for the market.Owing to its tastiness and relatively more edibleparts,fish even of the grade of 100—150 g are readily acceptable to customers.The principal results of our experiments on the rearing of this fish,togetherwith the relevant biological data obtained,are given in this paper. 细鳞斜颌鲴是在我国分布较广而又为群众所喜爱的一种野生经济鱼类。这种鱼在某些天然水体中可成为优势种群,产量较大,最高可以占总渔获量的50%以上。但有许多水体中却没有这种鱼或数量不大。通过试验和研究,我们已能对这种鱼进行大规模的人工繁殖和苗种培育,近年来,已将数万尾大规格鱼种投放到一原来只投放“家鱼”(泛指鲩、青、鲢、鳙,以下均同)的水库中,并将检验其增产效果。实践证明斜颌鲴在池塘中与现有“家鱼”混养时,非但不影响“家鱼”的生长,并可使池塘总产量增加10%以上;原因是这种鱼主要以其他养殖鱼类尚未利用或未能充分利用的腐屑、腐泥和着生藻类为食物。该鱼头两年生长较快,两周年可达一市斤左右,并第一次达到性成熟,这种规格的鱼上市就是经济价值高的优良食用鱼。因其在池塘中易于捕捞,故也是丰产塘中轮捕轮放的好对象。按普通“家鱼”种的培育方法当年鱼可养成4寸左右,第二年底都能在半斤以上,大的可达8两半。由于该鱼头小肉多而味美,故即使2—3两重的鱼在市场上也受到顾客的欢迎。本文还介绍了养殖这种鱼的方法及其有关的生物学资料,并讨论了在天然水体中促使这种鱼增产的可能途径。 This article briefly describes the functions, components, characteristics and working principles of Model LJ鈥? computer for vending machines. This machine is purposely used for wholesale, retail, and other business in grain shops and may be used in other commercial departments if slightly modified. It is able to calculate the sum paid by. every customer, to display digits with a number generatar and print out automatically. It can sum up and store the amount of each variety of goods sold out in each day... This article briefly describes the functions, components, characteristics and working principles of Model LJ鈥? computer for vending machines. This machine is purposely used for wholesale, retail, and other business in grain shops and may be used in other commercial departments if slightly modified. It is able to calculate the sum paid by. every customer, to display digits with a number generatar and print out automatically. It can sum up and store the amount of each variety of goods sold out in each day and the total sum remained. It can also carry out circulating display at any instant. This machine with maltifunction has the advantages of simple in circuit, easy in operation and low in cost. 本文介绍了78年协助济南市中区粮局研制的LJ—1型售粮(货)计算机的功能、组成、特点及工作原理。该机是适用于粮店业务的专用计算机,稍加改动,也可用于其他商业部门的批发和零售业务。该机能完成对每顾客所付金额的计算;能数码显示各类数字并进行自动打印;能将一天所售各品种数量、总金额进行累计储存,并可随时进行循环显示。该机具有电路简单、操作方便、多功能、成本低等优点。可代替原人工计算、填卡、结账等工作。经有关单位鉴定,性能基本达到设计要求,在商业部门有一定的推广使用价值。 The new standards on the quality of tungsten concentrates issued in 1981, coupled with the achievements gained in scientific research and the realization of technical modifications, has resulted in new advances on China's production of quality tungsten concentrates.The implementation of national standards on the quality of tungsten concentrates plays an important part in organizing production, unifying prices and linking up production with selling. The previous standards on the quality of tungsten concentrates... The new standards on the quality of tungsten concentrates issued in 1981, coupled with the achievements gained in scientific research and the realization of technical modifications, has resulted in new advances on China's production of quality tungsten concentrates.The implementation of national standards on the quality of tungsten concentrates plays an important part in organizing production, unifying prices and linking up production with selling. The previous standards on the quality of tungsten concentrates have not been revised for more than ten years so that the tungsten concentrates turned out at various tungsten mines in China to the standards C Table 1 promulgated in 1965 could not meet the needs of markets at home and abroad because of their low tungsten grades, few controlled impurity element numbers and unduly broad limits on detrimental constituents. In order to bring about a change in the situation, new standards were formulated, scientific research work was performed and production of quality tungsten concentrates has already been commenced.The newly formulated standards on the quality of tungsten concentrates are presented in Table 2. According to these new standards, there are three grades for wolffamite concentrate and scheelite concentrate each, totalled twenty varieties. The superfine grade is newly added. The superfine grade Ⅰ is quality raw material for tungsten-iron alloy production and direct steel-making because the limits on sulphur, phosphorus and many impurity elements in this grade are relatively strict. The superfine grade Ⅱ is quality raw material for hard alloys, tungsten filaments and products because the limits on calcium, molybdenum and many other impurity elements are also comparatively strict. Some previous products are retained to meet the needs of the customers of long standing. At the same time, flexibility in implementing the standards is emphasized, namely, the enterprises are allowed to formulate and conduct their own standards for superfine grades to customer's needs and resources characteristics; In case of special needs and on the principle of mutual benefit, both supply and demand sides could consult with each other about the index of a few items spcified in the standards and other requirements and come to a settlement. This flexibility will convenience both producers and customers.The main a chievements gained in scientific research work are: 1) further cleaning of -60 mesh tungsten concentrate. In accordance with different characteristics of ores, gravity-magnetic, magnetic-flotation, gravity-magnetic-flotation-electric etc. Various flowsheets and appropiate technological conditions were adopted so that about 80% of products have become superfine grade concentrates through beneficiation; 2) comparatively thorough separation of wolframite from scheelite. Wet high-intensity magnetic separation alone or in combination with flotation was adopted to separate fine grain size wolframite from scheelite. Under better liberation conditions, the calcium content in wolframite concentrate could be reduced to 0.1-0.5% and the manganese content in scheelite concentrate below 0.5%. Two kinds of wet high-intensity magnetic separator, Model SQC-2-1100 and Model SQC-2-700, were developed, which were suitable for tungsten cleaning. 3) further removal of some impurities from coarse grain size concentrates. After crushing, the coarse grain size concentrates went through table flotation and flotation to make their sulphur content reduce to<0.5%, and bring up concentrate grade and cut down phosphorus content correspondingly. 4) further cleaning of scheelite concentrate. By means of readjustment of ore dressing technology, quality scheelite concentrates were? produced.The production of quality tungsten concentrates has already been started in China in 1982. At some tungsten mines, the technical modification for quality tungsten concentrate production has been completed, at others, the modification is lacing carried out in preparation for the quality tungsten concentrate production. Because China 本文评述了为提高钨精矿质量于1981年颁发的钨精矿质量新标准;概述了科研和技术改造取得的成果;介绍了我国生产优质钨精矿的最新进展。
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