火山石和改性凹凸棒土对初沉单元净化效果的影响

为了对养殖尾水处理系统中沉淀单元净化能力进行优化,以改性凹凸棒土（Al@TCAP-N）和火山石作为研究材料,利用显微观察和比表面积测定研究其净化机理,以TN、TP、COD_Mn的浓度和去除率为检测指标,研究初沉单元中两材料的净化模式、运行参数和回收利用能力。结果显示,Al@TCAP-N具备较大比表面积（28.58 m²·g^-1）,微生物难以附着;火山石比表面积较小（10.9 m²· g^-1）,适宜微生物附着。将两者复合使用并添加外源微生物,0~48 h水质净化效果最佳,此模式对TN、TP和COD_Mn的去除率分别可达41.25%、45.31%和54.97%。深入研究该模式的运行参数,结果显示两种材料最适合的复配质量比为1∶1,复配时最适添加量为1 g·L^-1,且微生物直接投加于水体中的净化效果好于固载于材料上。对使用后的净化材料进行研究,发现净化材料能够通过简单的冲洗、烘干重复利用,并且每克材料最多可富集201.73 μg氮和34.98 μg磷,具有潜在的资源化利用价值。研究表明,将净化材料与外源微生物联用,能够有效、实用地增强养殖尾水沉淀单元水质净化效果。     

枣不同品种果核性状研究

枣核是鉴定品种的重要特征,对冬枣、榆次团枣、婆婆枣、紫圆枣等37个枣品种和1个毛叶枣品种台湾青枣的果核和种仁的外部形态指标进行了详细地描述和测量,以研究枣不同品种果核、种仁各数量指标间的相关性,得出核纵径和核喙长的线性方程Y=-0.064 1+0.184X。     

Study on Seepage Model of Rock Mass in Baodingshan Grotto Area of Dazu County

Based on the analysis of hydrogeological condition, and hydraulic characteristics and hydraulic relation in rock mass,the seepage of rock mass in carved stone area has been generalized and its mathematics models established. By numerical simulating,correctness of Seepage models of rock mass have been proved.     

Genetic diversity and molecular epidemiology of the T strain of Plum pox virus

Very limited information is available on the origin, diversity and evolution of Plum pox virus (PPV) ‘Turkey’ (T) strain. Phylogenetic analyses based on partial sequences of 421 isolates and complete genome sequences of 57 isolates, representing the geographical distribution of PPV-T in Turkey, revealed the existence of several monophyletic and, in some cases, geographically limited groups within the PPV-T strain (Ankara-Konya1-Kayseri, Ankara-Balkan, Istanbul, Konya2 and Balkan). PPV-T diversity (0.018%) was found to be greater than that of PPV strains D and Rec but lower than that of the M strain when including the newly described and divergent M-Istanbul isolates, suggesting a long evolutionary history for PPV-T. The European part of Turkey in the Balkans, close to Bulgaria where PPV was identified for the first time, appears as a likely centre of origin for PPV-T isolates. The colonization of various parts of Turkey by diverse isolates from that region, followed by secondary local spread, is the most likely scenario for the diffusion of PPV-T in Turkey.     

Soil and water conservation in Tigray (Northern Ethiopia): the traditional dagat technique and its integration with introduced techniques

Between the cultivated fields in the highlands of Tigray, one finds, besides the recently introduced stone bunds, many lynchets, with a height ranging from 0·3–3 m. Grasses occupy the riser and a more or less large strip on the shoulder. Traditionally, farmers established an untilled strip of about 2 m wide at the lower plot limit. This grass strip reduced runoff velocity, allowed for water to infiltrate and trapped sediment. Year after year, these lynchets, locally called dagat, continued to grow. In this study, the dagat technique is characterized and its evolution and reasons for partial destruction are outlined. Stereoscopic aerial photo analysis shows for the study area near Hagere Selam (13 °39′N, 39 °10′E, 2650 m a.s.l.) that 20·7 per cent of the major dagats (more than 1 metre high) have disappeared between 1974 and 1994. These lynchets, however, remain an important linear element in the landscape (22·7 m ha⁻¹, i.e. their density on cultivated fields is much higher). Of the smaller lynchets, a great proportion has been levelled in order to increase plot surfaces and spread fertile soil over the field. Famines and impoverishment caused the farmers to increase short‐term agricultural production in this way. Since the 1980s, the farmers built stone bunds on most of the cultivated land. Their average length equals 56·1 m ha⁻¹ in the study area. The establishment of stone bunds results in the development of small terraces. Especially during recent years, there is a tendency to integrate the traditional knowledge of dagat with the building of stone bunds. A quantitative assessment of the effectiveness of both techniques must be made. Copyright © 2000 John Wiley & Sons, Ltd.     

注射LHRH-A对雌性石鲽血浆E_2含量的影响

采用放射免疫测定方法（RIA）测定石鲽（Kareius bicoloratus）生殖季节血浆雌二醇（estradiol）含量,观察注射外源激素促黄体激素释放激素类似物（LHRH-A）后血浆E2含量变动。结果表明,注射LHRH-A后6 h血浆E2水平显著升高,12 h显著下降,24 h略有下降,48 h回升但尚未达到处理前水平;对照组血浆E2含量在注射生理盐水（PS）后6 h显著下降,12 h、24 h持续下降,48 h略有回升但低于处理组。说明LHRH-A能有效促进血浆E2的产生和释放,但E2的产生和释放会受到环境胁迫和在实验过程中产生的操作胁迫作用的影响。     

桂味荔枝果顶形状与种核质量的关系研究

为实现桂味荔枝按种核质量进行工业分级,运用计算机视觉技术、相关分析和回归分析,计算和分析了桂味荔枝的单果质量、横纵比、容积、果顶曲率与种核质量的关系,结果表明:单果质量、横纵比、容积与种核成正相关,果顶曲率与种核质量成负相关且线性相关最显著.建立了果顶曲率与种核质量的回归模型.     

银杏种核采后处理对氰化物含量的影响

以银杏核用主栽品种佛指和洞庭皇为试材,对采收的种核进行CaCl_2溶液浸泡、~(60)Co辐照处理后,贮藏于室内,期间每隔20 d测定种核氰化物的含量和种胚的长度变化.结果表明:银杏种核内氰化物含量随着贮藏时间的延长而上升,在148 d左右后逐渐下降,其最低值比贮藏前高出35%~55%;CaCl_2溶液浸泡和~(60)Co辐照均能明显降低种核氰化物的含量,且品种间存在一定差异;银杏种核氰化物含量与种胚的长度呈极显著相关.     

麦饭石对家禽酵母饲料消化率的影响

采用Ｓｉｂｂａｌｄ的ＴＭＥ法进行盲肠未取盲肠公鸡的消化试验,以酵母饲料为基础对照日粮,以酵母饲料＋麦饭石（１００：１）为试验日粮。结果表明,麦饭石对去盲肠和未取盲肠公鸡的日粮摄入量和粪便排泄量无显著影响,面对排泄量与摄入量的比率产生显著影响;日粮消化率在基础日粮和试验日粮分别为：干物质７８．０３、７５．９２和８０．７５、７８．４２;能量８０．０７、８０．２５和８０．３４、８１．１６;氮２８．７４、     

潮间带垒石蒙网养鲍技术研究

1994年4月～1995年10月，在4个岩礁区共设置136个石垛，放养壳长1．3～3．0cm鲍苗55．1万只，进行潮间带垒石蒙网养鲍试验。对场址选择、放养密度、规格、投饵方法等进行了研究。结果：产商品鲍19．254t，平均亩产1397．8kg，平均壳长6．81cm，平均个体重39g，成活率89．6％，实现产值693.144万元、利润352.81万元。专家鉴定认为，养殖方式为国内首创，技术水平属世界先进。