三峡水库蓄水重力效应数值模拟

运用精密数值模拟算法。计算了三峡水库库首区不同蓄水高度的重力效应;对比分析了首次蓄水前后局部重力监测网观测到的重力异常与模拟计算结果。得出结论：三峡水库蓄水引起的重力效应非常明显．蓄水过程中的重力异常是多种效应的综合反映,其中蓄水本身的直接重力效应是主要的重力效应。     

0.1THz CARM放大器的计算机模拟与设计

以动力学理论为基础设计了一种工作频率为0.1THz的圆柱回旋自谐振脉塞（CARM）放大器,进行了详细的理论研究分析,同时采用粒子模拟软件进行计算机模拟及参数的优化设计,设计出增益达到26.1dB的放大器。还将粒子模拟结果与动力学理论数值计算结果进行比较和分析,结果发现粒子模拟和理论分析结果基本相吻合,且描述的规律一致,从而从两个方面证明了设计的可行性。     

基于Mann-Kendall法的长三角城市集聚效应空间结构研究

以长三角地区为研究区域,以制造业劳动力城市分布为研究对象,运用Ripley's K函数多尺度识别制造业劳动力空间集聚模式;并利用Mann-Kendall检验方法,查找制造业劳动力边际集聚突变的空间尺度,以此揭示长三角地区城市集聚效应的主要空间特征。发现主要有:①长三角地区制造业劳动力在空间上显著集聚,随着空间尺度的增加,集聚程度与空间尺度呈倒"U型"关系。当空间尺度为155 km时,长三角地区制造业劳动力集聚范围达到最大,此处城市间向心力和离心力实现均衡;②由Mann-Kendall检验结果可知,60 km是城市集聚效应间结构的突变点,即长三角地区地级市之间、地级市与直辖市间距离应不低于60 km,这种城市群结构将使得地级市下辖的县级市、县等既能享受城市集聚效应又能避免拥挤效应等不经济因素,具备较佳的发展条件;③在突变范围内,长三角地区城市集聚效应呈现"中心—外围"层级空间结构,以上海、苏州等中部地区城市为极核,带动周边城市发展,经济影响逐级向外递减。江苏北部、浙江南部城市集聚效应最小,表现出明显的梯度特征和地域差异性,这意味着长三角地区城市发展仍不均衡。     

海洋软黏土大直径沉桩贯入挤土效应

【目的】研究海上沉桩贯入软土地基诱发的挤土效应。【方法】利用有限元大变形RITSS程序,通过大量的参数分析,对海洋地基桩基础贯入引起的挤土效应、土体破坏机理、周围土体的水平和隆起位移,以及挤土效应的影响范围展开系统研究。【结果】将数值模型与锥形桩(圆锥贯入仪)经典理论解进行比对,获得了较好的一致性。对大量数值仿真结果进行统计,获得在海洋地基中沉桩时土体的径向位移和垂直隆起高度的定量化描述,桩周土在1~3倍圆桩半径范围内最大水平位移为0.26R。【结论】提出关于水平位移和隆起高度的计算公式,能够预测沉桩对临近土体扰动的影响范围,能较为准确地评估多桩系统中沉桩对临近桩基础的影响。     

超声空化影响生物效应与声学参量优化的研究

剖析了超声空化的形成及其引发的“聚变现象”对生物制剂的作用机理；重点研究超声空化(稳态空化和瞬态空化)与声学参量的相互关系及其控制方法。     

基于GEE的黄河流域植被时空变化及其地形效应研究

黄河流域作为中国东部平原的生态屏障,研讨其植被覆盖的时空变化有助于生态环境治理。本文利用GEE平台,基于Landsat数据通过像元二分模型反演了1990—2020年黄河流域植被覆盖度（FVC）,并通过Theil-Sen Median趋势分析和Mann-Kendall检验方法剖析FVC的时空变化趋势,挖掘出FVC趋势变化与海拔、坡度、坡向等地形因子之间的响应关系。结果表明：(1)黄河流域FVC整体呈现西北低东南高的空间分布趋势,其中低等FVC占整个流域面积的45%,主要集中于西北部干旱半干旱地区;(2)流域中部植被覆盖改善明显,占整个流域的57.07%,西北部和东南部退化程度相对较高;(3)植被覆盖受地形效应影响较为显著,在坡度大于40°及高程（-31～637 m）时高等级FVC占比较高,坡度8～18°及高程1852～2414 m范围内植被改善效果相对较好。结果可以为黄河流域生态环境保护及高质量发展提供科学支撑。     

水文重力效应改正中一维地下水模拟算法的对比

基于一维地下水渗透方程详细推导其有限差分解算过程,引入不同于显式差分的隐式差分和中心差分格式,对比分析不同差分格式对地下水模拟结果及其相应地下水重力效应的影响,并对其中的层间参数取值和非线性方程的线性化问题进行探讨。结果表明,在日本Isawa扇形地区超导台站,不同层间参数加权公式能够引起最大约0.15 μGal的重力效应差异,影响在1.9%以内;不同差分格式和线性化方法组合形式能够引起最大约0.12 μGal的重力效应差异,影响在1.5%以内。     

断层活动的重力效应

地球内部的热应力和重力是驱动地壳运动和地震活动的主要力源，而这些构造应力往往在地壳薄弱处──断层带发生作用。本文从断层在构造应力作用下有关参数发生变化这一情况出发，讨论它们的重力效应，所得结果表明，断层的几何参数和物性参数发生变化时，重力场将产生相应的变化。     

海面环境多路径效应建模研究

遵循多路径效应建模的一般原则,建立了海面环境多路径效应模型,并通过仿真数据验证了所建模型的有效性。     

井筒混合效应和表皮效应对注水井溶质径向弥散的影响

注水井理论模型研究一直是水文地质学领域的热点问题。充分考虑含水层的非均质性,利用两区MIM(Mobile-Immobile)对流扩散模型来描述溶质在含水层中的运移过程,同时考虑表皮效应和井筒混合效应,建立一种描述注入井附近含水层溶质径向运移的动力学模型。并采用Laplace变换、Stehfest数值逆变换得到了该动力学模型的半解析解。然后改变表皮区的有效孔隙度和径向弥散度以及井筒的半径,来分析固定观测点的溶质穿透曲线和溶质浓度分布曲线的变化规律。研究表明,井筒混合效应和表皮效应对穿透曲线、溶质径向运移过程和影响区域均有着非常显著的影响。在考虑井筒混合效应时,井筒半径越大,井筒效应越明显。而表皮区域有效孔隙度越大,溶质的迁移扩展速率越小;径向弥散度越大,观测点的溶质浓度曲线越陡峭,表明该点的溶质浓度变化速率较快,且能更早达到稳定值。与前人研究相比,本研究模型能更好地描述注水井中的溶质径向弥散过程。     

Research on modeling source effect of 3D CSAMT based on staggered-grid finite difference method

There is usually source effect in the field work of controlled-source audio-frequency magnetotelluric method.Source effect is a thorny problem during field working,data processing and interpretation.Therefore,it is very important for the results of field prospecting to model source effect and summarize its influence rules.Based on the previous research,the authors use 3D finite difference method to simulate the electromagnetic field and set different anomaly situation to study the source effect in near-field measurement,then conclude the in-fluence rules of source effect.Simulations provide the reference for the actual field work and data processing to correct the influence of source effect,so the information of the underground will be more approaching to the real.     

AGGLOMERATION AND RADIATION EFFECT OF THE PULL OF URBANIZATION

In order to explore the train of thought for China‘s urbanizing development and coordinated rural eco-nomic development, and to find good ways of solving rural problems through urbanization, this paper absorbs the push-and-pull forces theory and the systematic dynamic theory in the traditional population migration theories, views urbanization as a dynamic system, makes research on the push-and-pull mechanism of urbanization. The pulling power of urbanization is analyzed according to two aspects, the agglomeration effect and the radiation effect of cities. The agglomeration effect provides continuous propelling force for urbanization, and the radiation effect further accelerates the urbanization process by pushing forward the development of rural economy. Of course, the slow de-velopment of urbanization can result in the hindrance to rural economic development.     

水平面上太阳辐射空间模拟对比研究

面域的太阳辐射数据是进行其他各项有关辐射研究的基础。由辐射台站的点数据来模拟太阳辐射的空间分布时,传统的模拟方式都会产生精度与效率之间的矛盾。直接以辐射观测值与其影响因子建立非线性回归模型,以各因子的面域数据来模拟水平面上太阳辐射的空间分布,与引入了辐射基数值的模式相比,模型的误差更小,复相关系数大于0．96,运算效率提高29-286倍。当采用模拟的天文辐射经验公式来计算辐射基数时效率仍可提高2-11倍。用两种方式的回归模型模拟中国1km栅格的水平面太阳辐射,平均差值仅2.41％,而本文模式模拟结果与实测值更为接近。     

数字锁相频率源研究与设计

介绍了数字锁相环的基本原理、主要技术指标及集成频率合成器Q3236的功能特点。对Q3236外围电路参数进行了分析设计。同时也对系统性能进行了分析。     

Response of marine microalgae,heterotrophic bacteria and their relationship to enhanced UV-B radiation

Ozone depletion in the stratosphere has enhanced solar UV-B radiation reaching the Earth surface and has brought about significant effects to marine ecosystems. The effects of enhanced UV-B radiation on marine microalgae, heterotrophic bacteria and the interaction between them are discussed. The effects on marine microalgae have been proved to occur at molecular, cellular and population levels. Enhanced UV-B radiation increases microalgal flavonoid content but decreases their chlorophyll content and pho-tosynthesis rate; this rachation induces genetic change and results in DNA damage and change of protein content. There have been fewer studies on the effects of UV-B radiation on marine heterotrophic bacteria. Establishment of a nucroalgal ecological dynamic model at population and community levels under UV-B radiation has gradually become a hotspot. The effects of enhanced UV-B radiation on microalgae communities, heterotrophic bacterial populations and interaction between them will become a focus in the near future. This paper will make an overview on the studies concerning the effects of enhanced UV-B radiation on marine microal-gae and heterotrophic bacteria and the interaction between them.     

Study on virtual source method under complex overburden in horizontal well

In conventional seismic exploration,complex overburden prevents us from imaging the deeper under- ground structure,because near-surface velocity model cannot be efficiently simplified and accurately estab- lished． The virtual source method provides a promising solution,which images below a complex overburden without the knowledge of overburden velocities and near-surface changes． In this paper,the authors simulate the forward modeling under complex overburden with sources on the surface and receivers in the horizontal well, and reset the real sources into the horizontal well using the virtual source method,which subtly avoid the distor- tion effects of the complex overburden． Finally the underground structure can be imaged using Kirchhoff migra- tion,so the feasibility and advantages of the virtual source method are verified．     

林木冠层光合有效辐射分布模拟的研究

简述了冠层辐射分布的常用研究方法,介绍了光线跟踪技术的原理及其在辐射传播中的应用。针对树木模型提出正向光线跟踪的辐射传输模型,并详细阐述了模型假设、处理流程与主要算法。该模型针对光合有效辐射在树木冠层中的传输过程,采用正向光线跟踪的方法进行模拟,最后利用HSV与RGB颜色空间转换的特殊方法,直观表达了冠层辐射分布结果。在叶片光学特征分析的基础上,将该模型应用于林木冠层PAR分布模拟中,以得到冠层的反射率、透射率和吸收率等重要参数。结果表明,模拟数据与实测数据偏差不大,验证了正向光线跟踪的辐射传输模拟是有效的。     

SPATIAL ANALYSIS OF SOIL EROSION AND NON-POINT SOURCE POLLUTION BASED ON GIS IN ERLONG LAKE WATERSHED, JILIN PROVINCE

Data collection, factor composition, nappe analysis and integrative simulation of natural geographical factors in Erlong Lake watershed have been carried out based on GIS. The risk areas where non-point source pollution may occur were compartmentalized and assessed, and the total soil erosion and the runoffs of N and P with rainfall in this valley were worked out by experiment and GIS mapping. The study indicated that the main type of soil erosion was moderate (erosion modulus is 1000–2500t/(km²·a)) at present, and the intense erosion areas are located in dry land with variable slope east of the lake and the middle-south parts of steep slope mountainous region (erosion modulus is more than 5000t/(km²·a)). Though the area is small, it should be paid attention to. The trend of non-point source pollution (NSP) of nitrogen and phosphorus loss was corresponded with the soil erosion. Spatial distribution and the reasons of the distribution difference have been presented and it was emphasized that the human activities among the influence factors was the most important. It surely offers a scientific basis to control and prevent non-point source pollution in the watershed. Foundation item: Under the auspices of the National Natural Science Foundation of China (No.50139020-5-2) and Science & Technology Committee of Jilin Province (No. 20010602) Biography: WANG Ning (1952–), female, a native of Beijing, associate professor, Ph.D., specialized in water and soil conservation and pollution control. E-mail: nwang@nenu.edu.cn     

瞬变电磁法三维模拟计算研究进展

瞬变电磁法应用于矿产资源、环境工程等领域.目前主流的瞬变电磁三维正演模拟方法包括积分方程法、有限差分法、有限体积法和有限元法.随着观测环境的复杂化以及探测精度要求的提高,有必要研究瞬变电磁法高精度三维模拟计算,以便推动数据处理解释方法的进步.本文系统介绍了瞬变电磁三维正演计算研究进展,分析了准静态差分方程的构建和发射源...     

Textural research on the main source of the Changjiang River

The Chinese people began to research the main source of the Changjiang (Yangtze) River 2,400 years ago. Limited by the scientific level, they did not discover it. The Tuotuo River was determined as the main source of the Changjiang River in the 1970s. However, this was not correct, because when comparing the length of the Tuotuo River with the Dam River, the glacier length at the headwaters was added to the Tuotuo River, resulting in that the Tuotuo River is 1 km longer than the Dam River, keeping in mind that the glacier can not be regarded as part of the river. In the summer of 1986, we investigated the source of the Changjiang River, we accurately measured the length of both the Tuotuo and Dam rivers, we discovered that the Dam River was 353.1 km long, and the Tuotuo River was 346.3 km long, the Dam River thus being 6.8 km longer than the Tuotuo River. The discharge of the Dam River is 196.18 m³/sec., 2.6 times as large as that of the Tuotuo River, that of the Tuotuo River is 75.10 m³/ sec. The drainage area of the Dam River is 1.8 times as larger as that of the Tuotuo River; the drainage area of the Dam River is 30,715.7 km², the Tuotuo River is 16,691.0 km². Through synthetic analysis of the factors mentioned above, we came to the conclusion that the main source of the Changjiang River is the Dam River instead of the Tuotuo River.