A preliminary study on simplified simulation model of spring wheat growth

In the model developed in this paper, taking the characters and requirements of meteorological services into account, some conventional meteorological observations which are easy to be obtained have been ch.osen, and mathematical equations describing micro-growth processes of crops have been established on the basis of the field experiments, laboratorial analysis and computer's modelling tests with time interval of ten-days for several years (1987-1989), in accordance with the known biological and physical rules and corresponding reference literatures. It is a preliminary simplified simulation model of spring wheat growth in optimal water and nutrient conditions. The field experiments show that simulation results of this simplified model are satisfactory. The potential operational application and theoretical sense are significant in the meteorological forecast of yield and in the assessment of influences of climatic change on agriculture.     

试论洪涝对水稻的影响

洪涝灾害是我国主要的农业气象灾害之一，水稻遭受洪涝灾害的概率较大，研究洪涝对水稻的影响具有重要的意义。通过现场试验，对水稻不同生长阶段遭受洪涝灾害的影响和不同温度下遭受淹浸后的影响进行了研究，并用数理统计方法对水稻遭受淹浸后，其产量的一系列变化作了定量的分析。     

浅析基于科学发展观的太仓市水资源保护措施

本文以江苏省太仓市为实例，结合当今国内快速城市化地区水资源的保护现状，吸取了美国等发达国家对于城市水资源保护的先进理念和科学方法，有针对性地提出了基于科学发展观的当地水资源保护的有效措施，可供类似地区借鉴。     

不同预处理对纳氏试剂比色法测氨氮的影响

用纳氏试剂比色法测污水中氨氮含量,为了消除干扰物质对测定的影响,需根据水体受污染程度,对水样通过絮凝沉淀法或蒸馏法进行预处理.本文通过试验论证了即使对较清洁的水,也以蒸馏法预处理为佳,蒸馏法预处理后的测定值更接近真值.     

B级钢侧架圆角细节耐久性力学模型研究

根据Paris公式推导出适用于B级钢圆角细节耐久性分析的 ,在一定裂纹尺寸范围内的裂纹扩展速率公式及其检验方法 ,笔者模拟货车B级钢转 8A侧架的导框弯角内侧 (A区 )的圆角细部进行耐久性实验 ;以试验数据的检验证明 ,在 0 .4～ 4mm的尺寸范围内 ,选用的断裂力学模型是合理的 ;同时为建立合理的检修周期和寿命体系提供理论模型和安全评价基础。     

单季晚稻穗颈瘟气象预报集成模型

根据1985—1998年上海地区单季晚稻穗颈瘟发生程度资料、地面气象资料、500hPa高空环流因子和北太平洋海温场资料，挑选相关系数较高且稳定性好的预报因子，在应用逐步回归和逐步判别分析方法组建预报模型的基础上，集成了单季晚稻穗颈瘟发生程度的长、中、短期预报模型。3种预报集成模型的起报时间分别为当年的3月、7月和8月下旬。这3种预报集成模型对1985-1998年的历史拟合和1999—2002年的预报，误差均未超过1级。     

红厚壳在海南岛的分布及其生长习性

红厚壳在海南岛一直是适应性强，分布广泛的珍贵植物资源。调查结果表明，在经济建设，农业土地开发等压力下，海南岛的红厚壳植物资源正日趋减少，目前仅在琼山，文昌等地区还保留较丰富，南部地区已绝迹，西部地区也难以见到。     

四川茂县叠溪地质公园旅游开发探讨

在世界地质公园旅游兴旺发展的大背景下，从交通区位、旅游资源、旅游发展环境和区域旅游联系四个方面对四川茂县叠溪地质公园的旅游开发条件做出评价，并根据旅游资源特点进行旅游功能分区和旅游项目设计，最后提出实施品牌化开发战略，产研学一体化开发模式，以及妥善处理开发与保护、经济与文化两大关系这三项开发利用建议，力求使叠溪地质公园旅游持续、健康、快速发展。     

Estimating Time Windows for Burning Oil at Sea: Processes and Factors

This paper discusses processes and factors for estimating time period windows of in situ burning of spilled oil at sea. Time-periods of in situ burning of Alaska North Slope (ANS) crude oil are estimated using available data. Three crucial steps are identified. The First Step is to determine the time it takes for the evaporative loss to reach the known or established limitation for evaporation and compare this time-period with estimated time of ignition at the ambient wind and sea temperatures. The Second Step is to determine the water up-take of the spilled oil and compare it with the known or established limitation for water-in-oil content. The Third Step is to determine the necessary heat load from the igniter to bring the surface temperature of the spilled oil to its flash point temperature so that it will burn at the estimated time period for ignition of the slick.     

The Introduction of the Precautionary Principle in Danish Environmental Policy: The Case of Plant Growth Retardants

In this paper, we investigate the Precautionary Principle (PP) in action. Precaution is a fairly new concept in environmental policy. It emerged back in the 1960s but did not consolidate until the 1980s, as it formed part of the major changes taking place in environmental policies at that time. The PP is examined in three contexts. Firstly, we look at the meaning of the concept and how it is disseminated through the media and public discourses to the political arenas of Denmark. Then we examine how the idea is adopted to the political level. Thirdly, we look briefly at the first Danish translation of the principle into a practical context, which includes translations into concrete scientific practices. It is concluded that if the PP shall be more than a simple “idea” or a frequently used “term,” emphasis must be put on the transformation of the concept into concrete practices, like e.g., the alternative testing regimes that we show in the case of plant growth-retarding pesticides presented in this paper.