雪水当量主被动微波遥感研究进展

全球尺度大范围准确定量雪水当量信息对于气象、水文、水循环和全球变化等研究都具有非常重要的意义,对融雪径流预报、水资源管理以及洪水控制方面也具有重要作用.陆面过程模型和积雪过程模型等可以一定程度上模拟雪水当量分布,但是在时间和空间上存在很大的不确定性,还远未达到有效应用的需求,因此现今大范围的雪水当量获取主要依靠遥感手段.自1978年雨云-7卫星发射后,雪水当量微波遥感经历了30多年的发展,相关学者在雪水当量遥感方面做了大量研究工作,包括电磁散射/辐射建模、地面和机载实验、反演算法研究等方面,为未来的全球高分辨率雪水当量遥感观测计划奠定了很好的基础.本文将从电磁散射/辐射建模和雪水当量反演等方面总结近年来相关研究的现状和进展.     

Starvation on changes in growth and fatty acid composition of juvenile red swamp crawfish, Procambarus clarkii

The effect of starvation on physiological and biochemical indicators of body, muscle and hepatopancreas were investigated for juvenile red swamp crawfish (Procambarus clarkii), and the results showed the effect was obvious. In a 70-day starvation experiment, mean body weight, exuvial rate, ab- dominal muscle ratio and hepatosomatic index decreased significantly. The percentage of protein, fat, ash and moisture were also significantly affected. The protein content decreased sharply at Day 30 onward and the percentage of fat decreased rapidly from Day 50 and on. The percentages of ash and moisture started to increase significantly at Day 40 and 30 respectively. After the starvation experiment, the hepa- topancreatic total and neutral lipid content decreased slightly from 23.90% to 20.39% and 73.75% to 70.35%, while the hepatopancreatic polar lipid content increased from 23.81% to 27.32%. On the other hand, all the muscular total, neutral and polar lipid contents, and the muscular fatty acid compositions did not change significantly except for the hepatopancreatic fatty acid composition. The relative percentages of 14:0, 16:0, 16:1n-7 and 18:1n-9 were decreased by 55.17%, 11.11%, 8.5% and 6.70% from the initial values, and the relative percentages of 18:2n-6, 18:3n-3, 20:4n-6, 20:5n-3 and 22:6n-3 increased obvi- ously from 5.2%, 3.9%, 2.4%, 10.6%, and 13.7% to 7.1%, 5.0%, 2.8%, 11.5%, and 14.4% respectively. Preference of utilization of fatty acids from hepatopancreas during starvation was as follows: 14:0>16:0>16:1n-7>18:1n-9, and the conservation of highly unsaturated fatty acids was in the order of: 18:2n-6 >18:3n-3>20:4n-6>20:5n-3>22:6n-3.     

“操心”所长——记商丘市国土资源局睢阳分局路河国土所所长曹欣

“操心”所长者,曹欣也。年逾而立,身材高挑,黝黑的脸庞上有一双会笑的眼睛。2001年任所长。因其好操“闲心”被同事戏称、群众爱称之为“操心”所长,这里记述的是“操心”所长的二、三事。""“保护土地是我的职责,保障发展也是我的责任。如何既保护了耕地又使来之不易的招商项目落地生根开花结果,富一方百姓,这个心我不能不操。”"2004年是商丘市的招商引资年。位于睢阳区近郊的路河乡也筑巢引凤。12月初,一位江苏面粉加工商看中了路河乡大元子村西紧邻“207”省道的一片农田,乡政府工业办负责人当即和曹欣要好的同事说,分流是政府的事,你…     

对花岗石石材矿地质勘查工作的建议

本文在收集大量国内外花岗石石材的有关资料基础上,分析目前我国花岗石石材普查勘探地质工作中存在的主要问题,如选点的盲目性;地质勘查工作无章可循;摄明储量范围过大,规模不当,级别偏低等。并对地质勘查工作阶段划分及其普查阶段和详查阶段的要求提出具体建议,指出要在地质勘查工作中强调解决以下几个问题:①花色品种;②块度:③荒料率;④露采条件;⑤交通条件;⑥储量规模等。     

WATER POLLUTION IN CHINA:CURRENT STATUS, FUTURE TRENDS AND COUNTERMEASURES

Based on the statistical data related to water pollution in recent years, this paper firstly describes in detail the current status of water pollution and water quality in rivers, lakes, reservoirs, groundwater and coastal waters in China, then makes a comprehensive analysis on future trends of water pollution in China. The authors hold that the economic power, technology level and management level have determinative influences on the current status and future trends of water pollution. At last, this paper discusses briefly the policies and measures for preventing and controlling water pollution in the light of the national conditions.     

七种重金属离子及其相互作用下对等鞭藻(Isochrysis galbana Parke)3011生长的影响

本文主要就七种重金属离子对等鞭藻3011生长的影响进行了探讨。实验中分别用1,3,5,7 ppm四种浓度实验发现重金属离子对藻生长的毒害作用顺序是Cu>Cr、Cd>Zn>Ni>Pb。Pb~(2+)对等鞭藻3011生长有利而Cu~(2+)却有致命的毒性。双因子作用下,Pb~(2+)、Ni~(2+)可降低其他重金属离子的毒性,例如Cr~(2+)、Cd~(2+)。总的来说,无论是单因子还是双因子联合作用下,对等鞭藻3011的生长都有抑制作用。     

南极乔治王岛菲尔德斯半岛西湖柱状剖面藻类化石与环境演变

根据西湖柱状岩芯样品中藻类化石的分布与含量变化,推测本区在3600年前仍为冰川覆盖;距今3600～3000年前为冰缘浅湖期;3000～1200年前湖水稳定,气候环境相对较好;距今1200年至现代气候略有波动。     

利用人工神经网络预测电离层foF2参数

利用人工神经网络技术实现了电离层f_oF₂参数提前1小时预测.从f_oF₂时间序列本身的变化特征出发,根据时间序列相关分析结果确定网络输入参数.选用当前时刻f_oF₂值,预测时刻前一天的f_oF₂值,预测时刻前7天f_oF₂平均值,当前时刻前7天f_oF₂平均值,f_oF₂的一阶差分及表示当前时刻t的变量共六个参数作为神经网络输入,下一时刻值作为神经网络输出.对于太阳活动高年平均预测相对误差小于6%,均方根误差小于0.6 MHz,太阳活动低年平均预测相对误差小于10%,均方根误差小于0.5 MHz