海底沉积物弹性参数计算方法及误差分析

由海底沉积物的纵波速、横波速及湿密度，根据岩土力学原理，整理出一组计

DENSITY-OF-STATES OF THE 2-DIMENSIONAL ELECTRON-GAS STUDIED BY MAGNETOCAPACITANCES OF BIASED DOUBLE-BARRIER STRUCTURES

The magnetocapacitive response of a double-barrier structure (DBS), biased beyond resonances, has been employed to determine the density of states (DOS) of the two-dimensional electron gas residing in the accumulation layer on the incident side of the DBS. An adequate procedure is developed to compare the model calculation of the magnetocapacitance with the experimental C vs B curves measured at different temperatures and biases. The results show that the fitting is not only self-consistent but also remarkably good even in well-defined quantum Hall regimes. As a result, information about the DOS in strong magnetic fields could reliably be extracted.

快速热退火对高应变InGaAs／GaAs量子阱的影响

用固态分子束外延技术生长了高应变．In0．45Ga0.55As／GaAs量子阱材料．研究了快速热退火对高应变InGaAs／GaAs量子阱材料光学性质的影响．本文采用假设InGaAs／GaAs量子阱中的In—Ga原子扩散为误差函数扩散并解任意形状量子阱的薛定谔方程的方法，对不同退火温度下InGaAs／GaAs量子阱室温光致发光峰值波长拟合，得到了In原子在高应变InGaAs／GaAs量子阱中的扩散系数以及扩散激活能（O．88ev）．

A Particle-in-cell scheme of the RFQ in the SSC-Linac

A 52 MHz Radio Frequency Quadrupole (RFQ) linear accelerator (linac) is designed to serve as an initial structure for the SSC-Linac system (injector into Separated Sector Cyclotron). The designed injection and output energy are 3.5 keV/u and 143 keV/u, respectively. The beam dynamics in this RFQ have been studied using a three-dimensional Particle-In-Cell (PIC) code BEAMPATH. Simulation results show that this R,FQ structure is characterized by stable values of beam transmission efficiency (at least 95%) for both zero-current mode and the space charge dominated regime. The beam accelerated in the RFQ has good quality in both transverse and longitudinal directions, and could easily be accepted by Drift Tube Linac (DTL). The effect of the vane error and that of the space charge on the beam parameters have been studied as well to define the engineering tolerance for RFQ vane machining and alignment.

STATUS AND PROSPECTS OF HIRFL EXPERIMENTS ON NUCLEAR PHYSICS

HIRFL is an accelerator complex consisting of 3 accelerators, 2 radioactive beams lines, 1 storage rings and a number of experimental setups. The research activities at HIRFL cover the fields of radio-biology, material science, atomic physics, and nuclear physics. This report mainly concentrates on the experiments of nuclear physics with the existing and planned experimental setups such as SHANS, RIBLL1, ETF, CSRe, PISA and HPLUS at HIRFL.

“第七届全国绿色环保肥料(农药)新技术、新产品交流会”专题报告

本次会议有27个专题报告,各具特色、异彩纷呈,突出展现了腐植酸肥料(农药)领域开发应用的最新研究和开发进展。为了让读者了解本次会议取得的成果,本栏目按会议专题报告顺序,将报告提要、报告中具有代表性的图或表、报告人简介和报告评价等内容编辑刊出。见21～45页。

基于MODIS数据的草地生物量估算模型比较

准确估算草地生物量对合理规划区域畜牧业、评估草地植被的生态效益有重要意义。目前,在常用的遥感估算模型中,采用的植被指数和模型函数形式多样。本文根据野外生物量调查结果和MODIS数据,分别采用归一化植被指数(NDVI)、增强植被指数(EVI)和修正的土壤调节植被指数(MSAVI)建立了内蒙古科尔沁左翼后旗草地地上生物量和地上地下总生物量估测的3种(线性、乘幂和指数)模型,并进行了比较。结果表明:3种模型能够对草地生物量进行较好的模拟,其中指数模型效果最佳;3个植被指数(NDVI,EVI和MSAVI)与草地生物量均有较高的相关性,可用于该草地产量估测,其中MSAVI对地上生物量拟合效果最好(R2=0.900);NDVI和EVI的线性模型对总生物量的模拟明显好于对地上生物量的模拟。

科尔沁沙地南缘樟子松人工林地下水埋深季节变化

于2005年5—10月,在未经过度人为干扰(大面积人工造林及农田开发)的大青沟地区(42°52′N,122°55′E)和自20世纪50年代大面积人工造林并相应开发农田的章古台地区(42°43′N,122°22′E)分别选择了樟子松疏林草地和草地(撂荒地)、樟子松衰退后皆伐地(皆伐地)及不同年龄沙地樟子松人工纯林设置固定标准地,监测了一个生长季的地下水埋深动态变化。结果表明:生长季内地下水埋深呈现出4种类型:平稳型、"V"型、"N"型和"M"型。大青沟地区的疏林草地地下水埋深在生长季变化不大,平均地下水埋深为1.88 m;章古台地区的草地和皆伐地呈现5—7月升高,之后下降;林龄较小(23年)樟子松纯林变化幅度较大,生长季地下水埋深相差4.30 m;林龄较大(33、42、45年)樟子松人工纯林生长季地下水埋深波动变化,且变幅不一。总体上,地下水埋深表现为疏林草地(大青沟地区)<(章古台地区)衰退后皆伐地和草地<林龄较小樟子松人工纯林<林龄较大樟子松人工纯林。上述结果表明,大面积造林及农田开发是造成大青沟与章古台两地地下水埋深差别的主要原因;在章古台地区,不同植被覆盖与林龄也直接影响地下水埋深。