初装修混凝土楼地面一次成活施工工艺

在施工过程中,通过对模板、钢筋、混凝土、砌筑等方面的控制就能够保证混凝土楼地面的施工质量。     

砼结构开裂原因分析及预防

通过现场观察和查阅有关混凝土方面的资料,对混凝土结构裂缝产生的原因和预防措施进行了阐述.     

Oral bovine serum albumin immune‐stimulating complexes improve the immune responses and resistance of large yellow croaker (Pseudosciaena crocea,Richardson, 1846) against Vibrio alginolyticus

This study aimed to investigate effects of bovine serum albumin immune‐stimulating complexes (BSA ISCOMs) on immune‐related genes expression, serum nonspecific immunity and disease resistance of large yellow croaker (Pseudosciaena crocea). Fish were fed diets containing 3.5 ml of BSA ISCOMs per kg feed (experimental group) or 3.5 ml of phosphate‐buffered saline per kg feed (control group) for 1 week. The liver, spleen, head‐kidney tissues were sampled for determining gene expression of myxovirus‐resistant protein (Mx), major histocompatibility complex class II alpha chain (MHC II α), tumour necrosis factor‐alpha (TNF‐α) and interleukin‐10 (IL‐10) 30 and 90 days after feeding. Also, blood samples were collected for determining activities of serum superoxide dismutase (SOD), interferon alpha (IFN‐α), TNF‐α and alkaline phosphatase (ALP). TNF‐α and MHCⅡα gene expression in the liver, spleen, head‐kidney, as well as IFN‐α, TNF‐α and ALP activities in the serum, of experimental fish were significantly higher 30 days after feeding; while only TNF‐α and MHC II gene expression in the head‐kidney remained upregulated 90 days after feeding. The cumulative mortality of the experimental fish was significantly lower than control. This study indicated that BSA ISCOMs improved the immune response and induced protective immunity in large yellow croaker.     

基于被动声学技术的海洋生物测量研究进展

综述了开展基于被动声学技术实现海洋生物测量的重要性;介绍了国内外被动声学技术用于海洋鱼类测量的研究背景、发展现状、存在的问题和发展趋势。列举了常用的被动测量设备以及被动声学数字信号处理方法,包括数据采集、预处理、端点检测、特征提取和识别技术;分析了采用上述测量技术可以研究海洋鱼类的栖息地、生活习性以及人类活动对鱼类的影响。通过列举石首鱼和鳕鱼的发声研究,提出今后被动声学技术研究的重点应集中于各种被动鱼目标特征库的建立和完善,鱼类、海豚等海洋生物的被动声辐射机理的分析,具有代表性的声特征参数以及鱼类发声和特殊行为之间的关联的研究。     

Lipid nutrition of juvenile Litopenaeus vannamei II. Active components of soybean lecithin

Two experiments were conducted to investigate the active components of soybean lecithin for juvenile Litopenaeus vannamei. The first experiment was conducted to determine the dietary phosphatidylcholine (PC) requirement of juvenile L. vannamei, and to investigate whether other phospholipids (PL), mainly phosphatidylethanolamine (PE) and phosphatidylinositol (PI) were the active fractions of soybean lecithin. Seven levels of PC (0%, 0.35%, 0.7%, 1.4%, 2.1%, 2.8%, 4.2%) extracted from soybean lecithin (PC purity 93%) were used to determine the PC requirement; also, PE and PI (in a 25:22 proportion) were tested at 0.84% and 1.68% levels with PC levels controlled at 0.35% and 0.52% of diet to investigate the combined PE and PI effects. Results showed that no dietary PC requirement was evident based on shrimp growth and survival. Increasing purified PC in the diet decreased total lipid, free fatty acid and other PL levels in shrimp hepatopancreas (mid-gut gland) and increased PC level in shrimp muscle. However, other PL, mainly PE and PI, showed significant enhancing effects on shrimp growth when PC was provided at 0.35% or 0.52% of diet.

Another 4×2 factorial experiment was concluded to reevaluate the requirement of shrimp for PC by including purified PC at 0%, 0.7%, 1.4 % and 2.8% of diet with or without 0.1% cholesterol in the diet. A diet containing 1.4% PC provided by deoiled lecithin also was tested for comparison. Results showed no interaction between PC and cholesterol on shrimp growth, survival and feed conversion ratio (FCR). Compared with the apparent growth-enhancing effect of dietary cholesterol, the effect of purified PC was negligible. With PC at 1.4% of diet, the presence of other PL from lecithin or 0.1% cholesterol significantly enhanced shrimp growth and FCR.

In summary, purified soybean PC showed different effects from deoiled lecithin on shrimp growth, lipid composition, and relationship with dietary cholesterol. Beneficial effects of soybean lecithin on growth of L. vannamei could be attributed to the presence of PL other than PC in the diet under the experimental conditions of this study.     

云南冷凉山区退耕还草混播组合筛选研究

为了配合云南省退耕还草工作的全面实施,2002-2003年在滇西北冷凉山区退耕地带进行了牧草混播组合的筛选试验。根据各混播组合的草层高度、豆草率、叶比重和干草产量等经济指标,筛选出适合云南冷凉山区退耕还草的最佳混播组合是:多年生黑麦草+白三叶。该组合在生长的第2年至少可刈割2次,干草产量达到7688.68kg/hm2,成年植株草高为62.3cm;群落中豆科牧草的比重可达44.5%,叶所占的比例达到55.6%;而且地表始终覆盖良好。其次可选用多年生黑麦草+紫花苜蓿混播组合,其综合经济性状略低于前一组合。     

北京低山地区油松人工林立地指数表的编制及应用

使用252块北京市低山地区油松人工林标准地资料,统计分析各标准地优势木平均树高与年龄的关系,以双曲线式拟合树高生长导向曲线,编制出适用于该地区的油松人工林立地指数表;经X2检验、落点检验和树高生长量检验后证明所编表合格;使用该表对252块标准地进行立地质量评价,结果表明,63%的标准地立地质量处在中等水平;油松最适宜生长的立地条件为阴坡厚土.     

Infection of Myxobolus turpisrotundus sp. n. in allogynogenetic gibel carp,Carassius auratus gibelio (Bloch), with revision of Myxobolus rotundus (s. l.) Nemeczek reported from C. auratus auratus (L.)

Infection of a Myxobolus species, previously identified as Myxobolus rotundus, was detected in 182 of 7892 (2.31%) allogynogenetic gibel carp, Carassius auratus gibelio, in a closed pond culture system in China. Morphological and molecular data showed that this myxosporean is a different species from M. rotundus parasitizing Abramis brama in Europe and is thus designated as a new species, Myxobolus turpisrotundus. M. rotundus (s.l.) ex C. auratusauratus is a synonym of M. turpisrotundus. Plasmodia of M. turpisrotundus develop in the subepidermal tissues of the body surface resulting in an unaesthetic appearance and causing severe economic losses. Prevalence of infection with the myxosporean plasmodia varied seasonally, increasing in winter and decreasing in spring. Prevalence was positively correlated to host size, but no host sex‐specificity was found. No infection was observed in other fish species (grass carp, bighead carp and yellow catfish) reared in the same pond, suggesting that the parasite has a relatively strict host specificity. Plasmodia grew gradually as the parasite developed, and reached up to a maximum 5.6 mm in diameter. Plasmodia ruptured naturally to release the mature spores and host fish completely recovered with no mortality. Release of spores and regeneration of lesions were not correlated with water temperature. Histology showed that plasmodia developed sub‐epidermally, and that the wall of the plasmodia was composed of a multiple complex structure, including layers of fibroblasts, a collagenous membrane, melanophores and a layer of cup‐like cells of unknown derivation and function. The cup‐like cells are in direct contact with pre‐sporogonic stages located in the peripheral parts of the large plasmodia. No severe host inflammatory response was seen.     

水发海参中甲醛的气相色谱法测定

本文探讨了一种水发海参中游离甲醛的气相色谱测定方法。甲醛以2，4－二硝基苯肼衍生后，经OV－17柱分析，电子捕获检测器检测。方法灵敏度高，重现性好，且衍生产物稳定，室温下放置，4天内测定结果平行。