加拿大的鲑科鱼类及其养殖技术

鲑科鱼类（Ｓａｌｍｏｎｉｄａｅ）中的一些种类属于加拿大的主要经济鱼类,被列为捕捞或养殖对象。Ｍｃａｌｌｉｓｔｅｒ,Ｄ．Ｅ．１９９０年报道,目前加拿大有记载的鲑科鱼类共３８种,隶属于３个亚科。亚科一白鲑亚科Ｃｏｒｅｇｏｎｉｎａｅ,共３属,２０种。１．湖白鲑Ｃ．ａｒｔｅｄｉｉ（ＬｅＳｕｅｕｒ,１８１８）２．秋白鲑Ｃ．ａｕｔｕｍｎａｌｉｓ（Ｐａｌｌａｓ,１７７６）３．鲱形白鲑Ｃ．ｃｌｕｐｅａｆｏｒｍｉｓ（Ｍｉｔｃｈｉｌｌ,１８１８）４．霍伊氏白鲑Ｃ．ｈｏｙｉ（Ｇｉｌｌ,１８７２）５．汉特斯曼氏白鲑Ｃ．…     

国家太空竞争力与地缘政治互动关系研究北大核心CSCD

太空因其显著的地缘战略价值而成为国家等行为主体间地缘政治博弈的新空间,太空竞争力作为相关行为主体谋取太空领域优势地位的核心要素生成于其围绕着太空开展的竞争与合作之中。该文搭建太空竞争力与地缘政治互动关系分析框架,在对太空竞争力的核心构成要素进行解析后构建太空竞争力评价指标体系,对全球14个国家和欧空局的太空竞争力进行评价,以此为基础从太空竞争力与地缘政治格局的互动关系、太空国际合作关系中的地缘政治关系透视两个视角剖析太空竞争力与地缘政治的内在逻辑。研究发现:地缘政治格局中的压力对苏联/俄罗斯、美国、中国、欧空局、日本、印度和韩国发展太空竞争力起驱动作用,对加拿大、澳大利亚起“弱遏制”作用,对巴西、阿根廷起“强遏制”作用,国家太空竞争力发展水平能对全球、地区的地缘政治格局产生深刻影响;太空国际合作关系在一定程度上揭示了全球及区域尺度的地缘政治关系,当前美国在全球地缘政治关系中处于绝对优势地位且同欧洲地缘政治关系根深蒂固,以美国为首的西方国家对中国遏制严重,欧洲内部地缘政治关系较紧密但亦呈现分化态势,亚洲内部地缘政治关系分化严重。     

因子分析在藏北商旭金矿床地球化学勘查中的应用

西藏双湖县商旭金矿床位于班公湖—怒江成矿带中部,矿体受NWW向断裂构造控制,呈脉状、透镜状产出,赋矿围岩为木噶岗日群炭质板岩及变质砂岩,矿石矿物为自然金,矿石类型主要为石英脉型与绢英岩型,为一典型的造山型金矿床。在对矿床地质特征、成矿条件分析的基础上,利用矿区岩屑地球化学数据,运用因子分析等多元统计方法,研究矿区地球化学元素组合,共划分出Cu-Pb-Zn元素组合分区、Au-Ag元素组合分区、As-Sb元素组合分区以及W-Mo-Bi元素组合分区等4个地球化学分区,绘制了因子得分等值线图,并在此基础上探讨找矿方向。结合矿区地质特征认为,Au、Ag元素组合和As、Sb组合为商旭金矿床的最佳地球化学标志元素,下一步地质工作重点应放在Ⅱ_1号、Ⅲ_1号矿体深部及周围,同时可布置适当的工程在Ⅲ号矿段西部A预测区,以追索Ⅲ_1系列矿体向西的延伸。     

武汉年平均气温的灰色预测

本文利用武汉80年的年平均气温资料,在对气温时间序列进行谱分析的基础上,利用灰色系统中的二阶动态预测模型——GM(2,1),对武汉气温未来的变化趋势进行了分析。得出武汉仍将处于偏冷期,预计90年代初开始转为回升,下世纪第10年后出现明显偏暖。     

中国耕地利用集约度结构变化及其区域差异

Based on the data from the Cost-benefit Data of Farm Produce and the China Agricultural Yearbook, this paper divided the intensity of cultivated land use into labor intensity and capital intensity, and then analyzed their temporal and spatial change at both national and provincial levels between 1980 and 2006. The results showed that: (1) At the national level, labor intensity on food produce decreased from 398.5 day/ha in 1980 to 130.25 day/ha in 2006; and a continuous decrease with a steep decline between 1980 and 1986, a slower decline from 1987 to 1996, and another steep decline from 1997 to 2006. On the contrary, capital intensity shows an increasing trend since 1980. As to the internal composition of capital intensity, the proportion of seed, chemical fertilizer and pesticide input decreased from 90.36% to 73.44% and the proportion of machinery increased from 9.64% to 26.56%. The less emphasis on yield-increasing input and more emphasis on labor-saving input are the main reasons for a slow increase of yield per unit area after 1996. (2) At the provincial level, the developed areas have lower labor intensity and higher capital intensity. The less developed ones have higher labor intensity but lower capital intensity. From the viewpoint of the internal composition of capital intensity, labor-saving input accounts for more proportion in the developed areas than that of other areas. The main reason is that in these developed areas, labor input has become a constraint factor in food production as more and more labors engaged in off-farm work. Farmers increase the labor-saving input for higher labor productivity. However, in the less developed areas, the major constraint is the shortage of capital; food production is still depending on labor and yield-increasing inputs.     

鮸状黄姑鱼胚胎和仔鱼发育的实验生态

本实验研究了温度、盐度、 ｐＨ对鮸状黄姑鱼胚胎发育和前期仔鱼存活的影响。结果表明,鮸状黄姑鱼受精卵孵化的温度范围为１５～３０℃,最适孵化温度为２５～３０℃;孵化盐度范围为１５～４５,最适孵化公度范围为１５～２５;ｐＨ值在５．００～８．９９范围内,受精卵孵化率没有显著的差异。鮸状黄姑鱼前期仔鱼存活的适合温度为１５～３０℃,最适温度为２５℃;适合盐度为１５～３５;适合ｐＨ值为５．９９～１０．０１。     

中华乌塘鳢(Bostrichthys sinensis) 和大弹涂鱼( Boleophthalmus pectinirostris) 成熟产卵过程中17a-羟基孕酮和前列腺素水平的研究

以酶联免疫吸附分析法测定了中华乌塘鳢和大弹涂鱼成熟产卵过程中卵巢液、精巢液、贮精囊液、雌鱼尿液和雄鱼尿液中的17α-羟基孕酮(17α-P)、前列腺素E2(PGE2)和前列腺素R2α(PGF2α)的含量。结果表明，中华乌塘鳢卵巢液中的17α-P和PGE，含量随着卵巢发育成熟而升高。性成熟前后卵巢液中的PGE，含量高于PGF2α。性成熟雄鱼尿液和贮精囊液中的PGE2含量显著高于精巢液或雌鱼尿液。性成熟前后雌鱼尿液中的17α-P、PGE2和PGF2α含量均显著高于卵巢液。性成熟和退化期雌鱼尿液中的PGE2含量明显高于PGF2α。性未成熟大弹涂鱼(第Ⅳ期)卵巢液中PGE2和PGF2α，含量极低；性成熟时(第V期)卵巢液中的PGE2、PGF2α和17α-P含量显著上升，PGF2α含量显著高于PGE2。     

准噶尔盆地腹部白垩系底部不整合的控油作用

燕山主幕运动形成的白垩系底部不整合在准噶尔盆地腹部地区广泛分布,腹部地区目前发现的油气藏多为白垩系底部不整合控制下的地层-岩性油气藏.从不整合的形成、结构特征等方面论述了不整合对油气的控油作用,具体表现:①风化作用有效地改善了不整合面下砂岩储层的物性;②形成了多套良好的储盖组合;③不整合面下形成多个地层型圈闭;④不整合的形成期是一次重要的成藏和调整期.     

彩色图像信息处理的IIS理论及实质

论述了一种用于彩色数字图像信息处理的ＩＩＳ理论及技术,它比目前所使用的基于模拟图像信息处理理论的图像处理技术更加确切而实用,它将对今后图像信息处理技术的发展起到非常大的作用。     

NUMERICAL SIMULATION ON THE RESPONSE OF LAND SURFACE TO SEVERE WEATHER

A coupled model of RAMS3b(Regional Atmospheric Modeling System,Version 3b)andLSPM(a land surface process model),in which some basic hydrological processes such asprecipitation,evapotranspiration.surface runoff,infiltration and bottom drainage are included,has been established.With the coupled model,we have simulated the response of soil to the severeweather process which caused the disastrous flood in north italy during 4-7.November,1994,simultaneously compared with the observation and the original RAMS3b,which has a soil andvegetation parameterization scheme(hereafter,SVP)emphasizing on the surface energy fluxes,while some hydrological processes in the soil are not described clearly.The results show that the differences between coupling LSPM and SVP exist mainly in theresponse of soil to the precipitation.The soil in the SVP never saturates under the strong input ofprecipitation,while the newly coupled model seems better,the soil has been saturated for one dayor more and causes strong surface runoff,which constitutes the flood.Further sensitivityexperiments show that the surface hydrological processes are very sensitive to the initial soilmoisture and soil type when we compared the results with a relatively dry case and sandy soil.The coupled model has potentiality for simulation on the interaction between regional climateand land surface hydrological processes,and the regional water resources research concerningdesertification,drought and flood.