转基因鱼生态效应的评价

转基因鱼的优良经济性状为水产业提供了巨大的发展潜力，但转基因鱼释放到自然环境后的生态效应则引起了很多争议。文章分析了转基因鱼的生态风险，并讨论了特洛伊基因效应模型。考虑到环境中各个生态因子对生物体表型的影响，生态学家在对转基因鱼进行生态风险的评价时，不能仅仅依赖于实验室的研究和理论模型，而需要建立人工模拟生态系统，从而得到全面、可靠的结论。     

SOD与酪氨酸酶共存时各自的活性

本文采用NBT(氮兰四唑)光还原法,测定了在酪氨酸酶存在下SOD酶的活性,并采用生成DOPA红的方法测定了SOD酶存在下酪氨酸酶的活性.并做了一系列干扰实验,实验结果指出:在酪氨酸酶存在下SOD催化O_2~??+O_2~??+2H~+??H_2O_2+O_2的反应活性降低,而在SOD存在下酪氨酸酶催化DOPA生成DOPA红的反应有明显抑制作用.     

大旅游视野中的休闲产业

大旅游概念具有三个方面的含义:强调旅游就业的作用、提高旅游服务质量和文化内涵、"旅游—旅游休闲—休闲旅游—休闲"是旅游业发展的客观规律。因而,休闲产业的崛起是自然而然的事,并不依人的意志为转移。传统的旅游业要发展,要顺应时代潮流,就必须拓展它的外延和丰富它的内涵,在此过程中,休闲产业将大有作为。     

交-直-交变频技术在机车轮箍加热炉上的应用

电力机车轮箍更换工作量大，耗电量大，加工时间长，直接影响电力机车检修任务的顺利完成。采用交－直－交变频技术的中频加热炉，不仅可极大提高工作效率，节约电力,资源资源，而且可改善工作环境。     

Antarctic fishes survive exposure to carbon monoxide.

The extensive in vivo conversion of haemoglobin to the carbon monoxide derivative has no discernible effect on the survival of the red-blooded Antarctic fish Pagothenia bernacchii. Analysis of caudally sampled blood of cannulated specimens revealed that reconversion of carbon-monoxy haemoglobin to oxyhaemoglobin was complete within 48 hours. Thus, under stress-free conditions, haemoglobin is not necessary for survival of P. bernacchii. Red-blooded Antarctic fishes can carry oxygen necessary for routine delivery dissolved in plasma, in a similar way to the haemoglobinless Channichthyidae, although they lack the morphological and physiological adaptations which allow the latter to prosper without any haemoglobin.     

Determining the temperature of petroleum formation from the kinetic properties of petroleum asphaltenes

Knowledge of the timing and location of petroleum formation is important in assessing the extent of available reserves in hydrocarbon-forming basins. This can be predicted from the thermal history of a basin and the kinetic parameters that characterize the thermal breakdown of kerogen in source rocks. At present, the kinetic parameters of kerogen breakdown are experimentally determined using immature rock samples from basin margins, but questions remain about the accuracy of this approach, especially when significant variability is observed within individual source units. Here we show that the kinetics of hydrocarbon generation from petroleum asphaltenes can be used to determine the temperature conditions of the actual source rock at the time of expulsion of the sampled petroleum. This relationship reflects the structural similarity of asphaltenes to the parent kerogen. We expect that our approach may be used as a comparatively simple alternative method for assessing the petroleum generation characteristics of a given basin, which will allow for better estimates of the available oil resources and the risks associated with their exploration.     

基于参数识别应用Backstepping design控制Lue′s混沌吸引子

混沌控制在最近十几年的研究中已经取得了长足的进展，形成了许多比较成熟而且有效的控制技术和方法，如：OGY控制、线性状态空间反馈等．但对于带有未知参数的系统，前面提到的方法常常无法达到预期的控制．通过构造识别函数识别Lue′s混沌系统的未知参数，然后应用Backstepping design控制Lue′s混沌吸引子，将Lue′s混沌吸引子控制刮一个稳定的周期轨道，通过数据模拟证明了该控制方法的有效性．     

2001年全国大学生数学建模赛题的若干评述

文章是对2001年度全国大学生数学建模题中B，C，D三题的评述，旨在深化对竞赛题目的理解和认识，并展示数学建模的魅力。     

Possible stimulatory effect of retinoic acid on pulmonary macrophages

Summary Retinoic acid was administered to hamsters suffering from N-nitroso-N-methylurethane-induced fibrosing alveolitis. A significant increase in macrophage numbers was seen in the lungs of retinoid-treated animals as compared to the unsupplemented group.