Rice yield estimation using remote sensing and simulation model

Remote sensing techniques have the potential to provide information on agricultural crops quantitatively, instantaneously and above all nondestructively over large areas. Crop simulation models describe the relationship between physiological processes in plants and environmental growing conditions. The integration between remote sensing data and crop growth simulation model is an important trend for yield estimation and prediction, since remote sensing can provide information on the actual status of the agricultural crop. In this study, a new model (Rice-SRS) was developed based mainly on ORYZA1 model and modified to accept remote sensing data as input from different sources. The model can accept three kinds of NDVI data: NOAA AVHRR(LAC)-NDVI, NOAA AVHRR(GAC)-NDVI and radiometric measurements-NDVI. The integration between NOAA AVHRR (LAC) data and simulation model as applied to Rice-SRS resulted in accurate estimates for rice yield in the Shaoxing area, reduced the estimating error to 1.027%, 0.794% and (−0.787%) for early, single, and late season respectively. Utilizing NDVI data derived from NOAA AVHRR (GAC) as input in Rice-SRS can yield good estimation for rice yield with the average error (−7.43%). Testing the new model for radiometric measurements showed that the average estimation error for 10 varieties under early rice conditions was less than 1%. Project supported by the National Defense Scientific and Technological Committee of China(No. Y97#14-6-2)     

基于客货运量的新疆城市等级体系分析

应用集中系数、区域非均衡系数、改进的重力模型对客货运量分别进行评价,并通过定性的方法对结果进行修正,得出结论:(1)新疆城市客货运的集中程度差异明显;(2)新疆客货运输的节点不一致,呈现出不同的变化趋势;(3)目前新疆基本形成以乌昌地区为中心,以"奎屯-乌苏"双核城市和喀什为次中心,以石河子、博乐、库尔勒、阿克苏、阜康为区域中心,其他城市为区域次中心的城市等级体系.     

Investigation of a naturally patinated bronze artifact originating from the outdoor statuary group of Mathias Rex

The present work aims to investigate the morphology and composition of natural patina formed after long-term atmospheric exposure (∼100 years) on the bronze screws used in assembling the statuary group of Mathias Rex, placed in the center of Cluj-Napoca, Romania. The chemical composition of the bronze and of the natural patina, formed on the screws’ surface were determined by X-ray fluorescence analysis, and the morphology of the latter was determined by SEM - EDX cartographies.     

Effect of solar electron temperature on pep solar neutrino flux in the chlorine solar neutrino experiment and the gallium solar neutrino experiment

1 Introduction a In this paper, we calculated the capture rates of pep solar neutrino in the chlorine and gallium solar neutrino experiments according to the standard solar model (SSM)[1-3] in which there are five separate neutrino sources within proton-proton chain involving the following nuclear reactions. 2 p + e ?+ p → H + νe (1) 2 p + p → H + e ++ νe (2) 2 Approximation calculation The rate of the pep reaction, p + e ?+ p → 2 H + νe, can be expressed in terms of the rate of reacti…     

人类认识宇宙的新窗口──2002年诺贝尔物理学奖评介

评介了探测中微子、X射线的原理、方法，讨论了中微子质量不为零和一系列宇宙X射线源的发现、对其相关理论的冲击和充实、及其深远意义。     

Hans Bethe, the sun and the neutrinos

We give an elementary review of recent discoveries in neutrino physics, culminating in the solution of the solar neutrino problem and the discovery of neutrino mass. Atmospheric neutrinos, reactor neutrinos and other important developments are also briefly described. G Rajasekaran is a theoretical physicist at the Institute of Mathematical Sciences, Chennai. His field of research is quantum field theory and high energy physics. Currently he is working in the area of neutrino physics.     

厦门市大气气溶胶化学特征研究

于2004年～2005年采集厦门市三个代表性季节大气气溶胶PM10样品,利用X-射线荧光光谱、离子色谱、热光碳分析仪分析其主要化学成分。结果表明: 气溶胶的化学成分浓度呈现春季最高、冬季次之,夏季最低的季节变化特征。其中,二次离子SO42-、NO3- 与NH4+ 占到近40%;总碳TC浓度占21%;Al、Si 、Ca和Fe等地壳元素仅占总质量浓度的13%;海盐离子占7%,二次离子污染是影响厦门环境空气质量的主要因子。     

极端干旱对若尔盖高原泥炭地生态系统CO2通量的影响

采用野外控制试验和静态箱法,研究极端干旱事件对若尔盖高原泥炭地净生态系统二氧化碳交换（net ecosystem CO₂ exchange, NEE）、生态系统呼吸（ecosystem respiration, R_e）和总初级生产力（gross primary productivity, GPP）的影响及其响应机制。研究结果表明：极端干旱显著降低若尔盖高原泥炭地生态系统的NEE、R_e和GPP（P<0.05）,导致生态系统固碳能力减弱,而温度（空气温度和土壤温度）和土壤含水量（SWC）是若尔盖高原泥炭地碳收支变化的主要驱动因子。在对照处理（CK）和极端干旱处理（D）中,NEE、R_e和GPP与空气温度呈显著正相关关系（P<0.05）,极端干旱减弱NEE、R_e和GPP对空气温度变化的敏感性。表层土壤温度与NEE、R_e和GPP的相关性高于深层土壤温度与NEE、R_e和GPP的相关性。分析5 cm土壤温度与NEE和R_e的相关关系。极端干旱减弱NEE对5 cm土壤温度的敏感性,增强R_e对5 cm土壤温度的敏感性。若尔盖高原泥炭地生态系统NEE、R_e和GPP与土壤含水量显著正相关（P<0.05）,而极端干旱对土壤全碳、全氮和有机碳的含量无显著影响（P > 0.05）。     

典型河谷型城市冬季热场分布和热岛效应特征及其驱动机制研究——以兰州市为例

应用城市气候流动观测、定点观测、GIS空间分析等方法,模拟分析典型河谷型城市—兰州市的冬季热场、湿度场空间结构特征和演变规律;通过波文比系统观测实验,分析地—气能量交换过程和能量平衡特征,从根源上解释城市热场演变和城市热岛效应产生的能量驱动机制.利用观测数据,结合兰州城区和郊区气象台站1958-2004年的常规气象观测资料,分析冬季热岛强度的日、季节和年际变化特征,兰州市冬季热岛强度夜间强,白昼弱,一日中热岛强度最高的时段主要集中在子夜前后;个别时段的正午前后会出现短暂的城市“冷岛”现象;冬季热岛强度最强,夏季最弱,春秋居中;兰州市近50年热岛强度逐渐增强,线性趋势达到0.46℃/10a.定量分析城市化指数与热岛强度变化的关系,发现兰州市总人口、建筑面积与城市热岛强度都呈显著的线性相关关系.研究结果为河谷型城市的大气污染治理、生态环境建设、城市规划、土地利用等提供理论参考.     

加强特色学科建设,提高实践教学质量

通过对“大气探测实习”教学改革,围绕培训实习基地建设、基地功能发挥、实习内容调整、实践手段创新等方面,探索如何提高实践教学质量.在学校积极创造各种软硬件条件的基础上,强调以学生为主体,教师适当加以引导,调动学生主观能动性,才是提高实践创新能力的重要举措.