高寒草甸地区牧草生长量模拟模式研究

本文讨论了土壤含水量和蒸散量对牧草生长量的影响过程，提出牧草干物质增长模式，并根据青海海北高寒草甸地区的气象条件，对牧草生长量模式进行数值模拟，同时，与实测值进行比较，模拟结果与实测值趋向一致，可为牧草产草量预报提供一定实用价值和科学依据

1978～2008年中国湿地类型变化

分别基于美国陆地卫星(Landsat MSS/TM/ETM+)和中巴资源卫星(CBERS-02B)影像数据,以人工目视解译为主,完成了中国1978～2008年4期(基准年分别为1978,1990,2000和2008年)湿地遥感制图,并进行了大量的室内外验证.在此基础上,对我国湿地现状及近30年来湿地变化进行了初步分析,得到以下主要结论:(ⅰ)截止2008年,中国湿地面积约为324097km2,其中以内陆沼泽(35%)和湖泊湿地(26%)为主.(ⅱ)1978～2008年,中国湿地面积减少了约33%,而人工湿地增加了约122%.过去30年里湿地减少的速度大幅降低,由最初5523km2/a(1978～1990年)降为831km2/a(2000～2008年).(ⅲ)减少的自然湿地(包括滨海湿地和内陆湿地),其类型变化由湿地向非湿地转化的比例逐渐降低.初期(1978～1990年)几乎全部(98%)转换为非湿地;在1990～2000年间减少的自然湿地约有86%转化为非湿地,而在2000～2008年,这一比例下降为77%.(ⅳ)气候变化和农业活动是中国湿地变化的主要驱动因素,湿地变化在中国分为三大不同特征区域,即西部三省/自治区(西藏、新疆和青海)、北部两省/自治区(黑龙江和内蒙古)和其他省市区.其中西部区域尤其是青藏高原,湿地变化的驱动因子以气候增温为主;新疆湿地由于气候增温和农业活动共同作用造成变化不大.北部省/自治区的湿地变化则主要由农业活动引起;而其他省市区的湿地变化几乎完全受控于人类的农业经济活动

Coherent Synchrotron Radiation and Microwave Instability in Electron Storage Rings

This thesis work was dedicated to investigating coherent synchrotronradiation (CSR) and microwave instability (MWI) in electron rings.CSR is an important issue in modern electron/positron storage rings,where short bunch length and/or low emittance are usually desiredfor particle physics or to produce light.To better understand the physics of CSR, we developed a new code,CSRZ, for calculating CSR impedance for an arbitrarily curved chamber.The chamber has rectangular cross section. The CSR impedancecan be calculated with boundary conditions of perfectly conductingwalls or resistive walls. With low-level numerical noises and minimalnumerical damping, the code is well suitable for the task of calculatingCSR impedance in a series of bending magnets. With a tinyapproximation on the geometry of the chamber, which was assumedto be wiggling in the code, CSRZ can also be used to calculate thelongitudinal impedance due to coherent radiation in a wiggler (CWR).Therefore, CSRZ does ful_ll another mission of calculating the CWRimpedance in the wiggler sections of KEKB and SuperKEKB.An analytic eigenfunction expansion method was available to calculatethe longitudinal impedance due to CWR with rectangular chamber.The method used dyadic Green\u27s functions in electromagnetic theoryand was rigorous for the case of straight chamber. Substantial alterationswere performed in order to make it applicable to calculatethe imaginary part of CWR impedance related to the beam self-_elds.Therefore we re-derived the theory and did _nd the full expressions forCWR impedance. With shielding of chamber, the CWR impedanceindicates resonant properties which were not seen in the theory forCWR in free space. The analytic work also provides excellent benchmarkingto the CSRZ code.The last part of this thesis addresses microwave instability (MWI)in the KEKB low energy ring (LER) and the SuperKEKB positrondamping ring (DR). Code development for simulating MWI was discussed_rst. For the KEKB LER, the impedances of various components,including CSR, were collected and used to survey the MWI.The CSR instability in the SuperKEKB DR was studied using existingtheories of instability analysis

Rapid Determination of Ni￣(2+), Fe￣(2+)and Cl-Ions Concentration in Ni and Ni-Fe Plating Baths

根据nI2＋在汞膜电极上的电化学还原和fE2＋、Cl在铂电极上的电化学氧化特性，采用dz-lb型电镀添加剂测定仪快速测定镍和镍铁镀液中nI2＋、fE2＋和Cl-的浓度。操作简便，快速，适用于电镀车间的镀液分析

基于对象和DEM的湿地信息提取——以洪河沼泽湿地为例

湿地资源遥感信息提取并满足一定的分类精度和效率,是湿地研究的关键问题之一。利用高分辨率的SPOT5影像数据,通过对研究区分别进行基于像素的监督分类和基于对象的分类,进行典型沼泽湿地专题信息提取,同时将面向对象分类与DEM辅助数据进行信息复合,探寻提升分类精度的方法。结果表明,基于对象和辅助数据DEM的信息提取,可以有效地改善遥感图像的分类精度