立方型状态方程结合Eyring理论在液体混合物黏度计算中的应用

Cubic equations of state (EOS) have been combined with the absolute rate theory of Eyring to calculate viscosities of liquid mixtures. A modified Huron Vidal gE-mixing rule is employed in the calculation and in comparison with the van Laar and the Redlich-Kister-type mixing rule. The EOS method gives an accurate correlation of liquid viscosities with an overall average deviation less than 1% for 67 binary systems including aqueous solutions. It is also successful in extrapolating viscosity data over a certain temperature range using parameters obtained from the isotherm at a given temperature and in predicting viscosities of ternary solutions from binary parameters for either polar or associated systems.     

磺酰脲除草剂与土壤的关系

自1975年杜邦公司George Levit博士发现磺酰脲类除草剂以来,已经成为一类主要的新颖除草剂,并促进化学除草技术的重大进步。目前世界范围内,共有8种磺酰脲除草剂已经商品化(表1),估计到九十年代中期会成倍增加,它们具有前所未有的除草活性,其使用量从千克/公顷惊人地下降到克/公顷。如今,甲黄隆每年用量为2～8克/公顷,使用200年也不过相当于过去传统除草剂一次使用量(1～4千克/公顷)。杀草谱广、用量低、对作物又有较大选择性,这些都是磺酰脲除草剂迅速成功的重要因素。同样重要的,它具有令人称     

用buprofezin和其他昆虫生长调节剂防治棉田害虫

苯甲酰苯基脲类化合物杀虫活性的发现揭示了化学防治公害的新途径.第一个商品化的化合物除虫脲能干扰昆虫蜕皮过程,因而作为昆虫生长调节剂使用.其主要作用方式为摄入,对某些昆虫也可通过触杀而起作用.其部分活性似乎与对于几丁质形成的生物化学过程的抑制作用有关.对于更有前途的酰脲化合物的探索工作得到了三个对农业害虫较除虫脲有更高活性的新型化合物:石原公司的chlorfluazuron、Calemerck公司的teflubenzuron     

Sequencing of multi‑robot behaviors using reinforcement learning

Given a collection of parameterized multi-robot controllers associated with individual behaviors designed for particular tasks, this paper considers the problem of how to sequence and instantiate the behaviors for the purpose of completing a more complex, overarching mission. In addition, uncertainties about the environment or even the mission specifications may require the robots to learn, in a cooperative manner, how best to sequence the behaviors. In this paper, we approach this problem by using reinforcement learning to approximate the solution to the computationally intractable sequencing problem, combined with an online gradient descent approach to selecting the individual behavior parameters, while the transitions among behaviors are triggered automatically when the behaviors have reached a desired performance level relative to a task performance cost. To illustrate the effectiveness of the proposed method, it is implemented on a team of differential-drive robots for solving two different missions, namely, convoy protection and object manipulation.     

世界首颗量子科学实验卫星“墨子号”交付使用

<正>世界首颗量子科学实验卫星"墨子号"在圆满完成4个月的在轨测试任务后,正式交付用户单位使用。"墨子号"是我国自主研制的世界首颗空间量子科学实验卫星,其在轨测试阶段全面完成了卫星平台测试、有效载荷自测试和天地一体化链路测试等工作,     

自动称重装置的国际建议

一、目的与回顾本文回顾自动称重装置国际建议发展的过程,并对已采纳的新建议的一些部分做说明。这些建议由OIML TC9/SC分会负责,秘书处仍为UK（NW/ML）（即英国、国家称重和测量实验室）。该工作始于1963年,当时为了非连续累计称重的需要,首次纳入国际建议。之后,原有的三个建议：R50皮带秤、     

面源污染中磷流失多重影响因素主成分分析

为全面了解对美国中部Illinois州具有浅层排水系统的轮作农业地区的面源污染问题,利用主成分分析方法及多元线性回归,对Little Vermillion River流域磷流失影响因素主成分进行分析.结果表明,磷流失的影响因素基本分为3大主成分:一是生物主成分,包括温度、植被类型、覆盖因子、生物量、散蒸量;二是水力主成分,降雨及流量;三是人为干扰主成分,施肥量及耕作内容.其中水力主成分对流失的影响最大,尤其是对浅层排水中磷流失的影响.     

我国研制成功世界首根百米级铁基超导长线

中国科学院电工研究所成功研制出了国际首根100m量级铁基超导长线,树立了铁基超导材料从实验室研究走向产业化进程的里程碑,标志着我国铁基超导材料研发走在了世界前列。     

航天科工集团新型森林灭火弹首飞试验成功

由中国航天科工集团公司贵州航天风华精密设备有限公司研制的新型森林灭火弹在某靶场进行了首次飞行试验,其飞行稳定性、射程、密集度和引信工作情况等性能均符合设计要求,试验取得圆满成功,为该产品后续研发工作的顺利开展奠定了基础。     

Deep mine cooling,a case for Northern Ontario:Part Ⅰ

Cooling energy needs,for mines in Northern Ontario,are mainly driven by the mining depth and its operation.Part I of this research focusses on the thermal energy loads in deep mines as a result of the virgin rock temperature,mining operations and climatic conditions.A breakdown of the various heat sources is outlined,for an underground mine producing 3500 tonnes per day of broken rock,taking into consideration the latent and sensible portions of that heat to properly assess the wet bulb global temperature.The resulting thermal loads indicate that cooling efforts would be needed both at surface and underground to maintain the temperature underground within the legal threshold.In winter the air might also have to be heated at surface and cooled underground,to ensure that icing does not occur in the inlet ventilation shaft-the main reason why cooling cannot be focussed solely at surface.