Development of in-situ testing equipment of rock and soil thermophysical properties     

Qinghua WANG  Youhong SUN  Qiang LI College of Construction Engineering  Jilin University  Changchun  China 《东北亚地学研究》2008,11(4):237-241

A mobile in-situ testing equipment used to detect geotechnical thermophysical properties was developed. The equipment is composed of a heat pump, frequency pumps, an electric tee joint regulator valve, some sensors, an electric control system, data acquisition and control system, which can do tests under the condition of extracting and storing subsurface heat. Applying the line source and the cylinder source heat transfer model, and combining the parameters estimation, the average thermophysieal property parameters of rock and soil will be calculated, which provides the basis for designing the ground source heat pump systems.  相似文献   

Spectral Features of Photon Bubble Models of Ultraluminous X-ray Sources     

Justin D. Finke  Markus Böttcher 《Astrophysics and Space Science》2007,307(1-3):325-327

The nature of Ultraluminous X-ray Sources – X-ray sources which exceed the Eddington luminosity for a ∼10 M _⊙ black hole – remains a mystery. One possible explanation is an inhomogeneous accretion disk around a solar mass black hole where photon transport through radiation-pressure dominated “photon bubbles” can lead to super-Eddington accretion. While previous studies of this model have focused primarily on its radiation-hydrodynamics aspects, here we explore some observational implications of such a model with a Monte Carlo–Fokker Planck radiation transport code.  相似文献   

一种公交换乘优化算法设计   总被引：4，自引：1，他引：3  

樊晓春  张雪英  刘学军  申琪君  樊晓明 《地球信息科学学报》2009,11(2):157-162

目前,在智能交通系统应用中,公交查询亟待解决其算法效率和换乘两大问题。对此,本文首先在分析乘客出行因素和公交网络特性的基础上,提出了关键站点的公交网络通达矩阵,分析了直达矩阵的计算原理;其次,阐述了城市道路网络最短路径算法,引入直达矩阵和公交网络通达矩阵,设计了一种公交换乘优化算法。该算法的基本原理:利用公交网络通达矩阵来确定哪些临时标记节点是潜在的永久标记结点,并始终优先考虑直达节点作为最短路径上的节点,从而实现对经典最短路径算法--Dijkstra算法的改进;最后,通过一个案例对该算法进行验证。实验表明,该算法不仅能够获得优于Dijkstra算法的性能,而且换乘次数更加合理。该算法能够适用于一般公交网络,对于换乘代价较高的公交网络更有优势。  相似文献   

Methane hydrate dissolution rates in undersaturated seawater under controlled hydrodynamic forcing   总被引：1，自引：0，他引：1  

N.K. Bigalke  G. Rehder  G. Gust   《Marine Chemistry》2009,115(3-4):226-234

The dissolution of in-situ generated methane hydrate in undersaturated, synthetic seawater (S = 35) was investigated in a series of laboratory-based experiments at P-/T-conditions within the hydrate stability field. A controlled flow field was generated across the smooth hydrate surface to test if, in addition to thermodynamic variables, the dissolution rate is influenced by changing hydrodynamic conditions. The dissolution rate was found to be strongly dependent on the friction velocity, showing that hydrate dissolution in undersaturated seawater is a diffusion-controlled process. The experimental data was used to obtain diffusional mass transfer coefficients k_d, which were found to correlate linearly with the friction velocity, u. The resulting k_d/u-correlation allows predicting the flux of methane from natural gas hydrate exposures at the sediment/seawater interface into the bulk water for a variety of natural P, T and flow conditions. It also is a tool for estimating the rate of hydrate regrowth at locations where natural hydrate outcrops at the seafloor persist in contact with undersaturated seawater.  相似文献   

环渤海地区农业地域功能演进及其影响因素   总被引：5，自引：1，他引：5  

鲁莎莎  刘彦随  秦凡 《地理学报》2019,74(10):2011-2026

农业地域功能是农业地理学的重点理论问题之一,也是关乎粮食安全和区域农业可持续发展的重要实践课题。以环渤海地区为例,通过构建评价体系开展农业地域功能划分及其演进分析,利用空间计量模型诊断农业地域多功能形成的影响因素。结果表明：① 环渤海地区生态保育功能的空间集中度较高,农产品供给、就业与社会保障、文化传承与休闲功能则较低,4种功能空间格局具有显著规律性。② 农产品供给功能显著增强,主要分布区域向平原农区聚集;就业与社会保障高值区从内陆向沿海转移;山地丘陵生态保育功能有所增强;市辖区及周边的文化传承和休闲功能较显著。③ 农产品供给功能主导型县域集中于冀中南平原、鲁西北冲击平原、胶莱平原和辽河平原西部;社会保障主导型集中在燕山山麓平原、滨海平原、胶东半岛以及黄河三角洲;生态保育主导型集中在冀北坝上高原、燕山山地地区,以及辽西、辽东山地丘陵区和京津冀都市圈周边;文化传承与休闲功能集中于京津冀、辽中南和济南都市圈及周边;综合型位于鲁西南黄淮平原与鲁中南丘陵地区。④ 自然因素对农产品供给、就业与社会保障和生态保育功能的形成均具有显著影响;社会经济因素对4种功能的作用则具有较大差异。  相似文献   

龙门山断裂带印支期左旋走滑运动及其大地构造成因   总被引：60，自引：6，他引：60  

王二七  陈智梁等 《地学前缘》2001,8(2):375-384

位于青藏高原东缘的龙门山构造呈北东—南西向将松潘—甘孜褶皱带和华南地块分割开。前者主要是由一套巨厚的三叠纪复理石沉积组成 ,分布在古特提斯海的东缘。后者由前寒武纪基底和上覆的古生代和中生代沉积盖层组成。位于汶川—茂汶断裂以东的前龙门山存在一系列倾向北西的逆掩断层 ,它们将许多由元古宙和古生代岩层组成的断片向南东置于四川盆地的中生代红层之上 ,构成典型的薄皮构造。许多研究由此断定松潘—甘孜褶皱带和四川盆地之间在中生代发生过大规模的北西—南东向挤压。然而 ,汶川—茂汶断裂西侧的松潘—甘孜褶皱带内部的挤压构造线大多是垂直于而不是平形于龙门山断裂带 ,这表明当时的挤压应力不是北西—南东向而是北东—南西向。近年来在龙门山构造带内发现 ,在三叠纪时龙门山断裂带在发生推覆的同时还经历过大规模的北东—南西向的左旋走滑运动 ,协调走滑运动的主要构造为汶川—茂汶断裂。走滑运动的成因与松潘—甘孜褶皱带北东—南西向缩短有关。汶川—茂汶断裂的左旋走滑在龙门山的北东端被古特提斯海沿勉略俯冲带的消减和发生在大巴山的古生代 /中生代岩层的褶皱和冲断作用所吸收 ,在龙门山的南西端被古特提斯海沿甘孜—理塘俯冲带的消减和松潘—甘孜三叠纪复理石的褶皱和冲断作用所吸?  相似文献   

Power and changes in the balance between ideology and pragmatism in the right wing Likud Party     

S. Ben-Rafael Galanti  W.E. Aaronson  I. Schnell 《GeoJournal》2001,53(3):263-272

When the Zionist executive abandoned Jewish rights to Trans-Jordanian Palestine, Jabotinsky established the Revisionist movement from which Etzel the Jewish right-wing underground movement in Palestine developed. This was the precursor of the Herut (Freedom) Party, from which the Likud party emerged in September 1973 to challenge the Labour Alignment (headed by the Israel Labour Party). Between the War of Independence (1948) and the signature of the Camp David accords (1978), the Government of Israel came under strong international pressure to solve the problem of the Arab refugees. During this time, dramatic changes took place in Herut's ideology and political status. In 1948, Herut was an outcast political party with a radical ideology, demanding the establishment of a Jewish Commonwealth on both sides of the Jordan. It perceived the Arab refugees to be a potential fifth column and the contiguous Arab states to be inimical. It strenuously opposed the Mapai led political Establishment's willingness to sign Armistice Agreements and make compromises with regard to Arab refugees. After Levi Eshkol replaced Ben-Gurion as the head of Mapai, Herut began to become part of the Israeli consensus and a member of the political Establishment. Herut served in Levy Eshkol's National Crisis Government before and during the 1967 war, and as the major force of Gahal, after the war. Concomitant with this, there were great changes in Herut's expressed ideology, chief among these were the tacit renunciation of trans-Jordan Palestine as part of the Jewish Commonwealth and the explicit acceptance of the Arab refugees as potential citizens of the State of Israel.  相似文献   

Adapting capitalism: Household plots, forest resources, and moonlighting in post-Soviet Siberia1     

Katherine R. Metzo 《GeoJournal》2001,55(2-4):549-556

Economic reform in post-Soviet Russia has proceeded unevenly, resulting in broad variation between rural and urban areas. In the case study presented here, I examine how Communism's `economy of favors' has been transformed into a localized quasi-capitalist economy, which predominantly operates outside the national market economy. Using data from two villages in Tunkinskij Raion of the Buriat Republic in Russia, I look at how people at a micro-sociological level have adapted to current economic conditions. In particular I examine the relationships between informal networks and the ability to intensify agricultural production on household plots, to gain access to a variety of forest resources, and to find seasonal, part-time, or one-time work outside the household and the formal labor market. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

亚热带森林岩溶区土壤CO_2迁移动态初步研究     

冉景丞  何师意  曹建华 《贵州地质》2001,(4)

贵州茂兰是研究森林覆盖下岩溶表层系统结构特征、运行规律的重要基地。本文初步研究了该地区碳迁移的若干特征 :(1)土壤剖面中CO2 浓度变化。秋、冬季土下CO2 浓度 ,5 0cm处始终高于 2 0cm处 ,而在春、夏季土壤剖面中CO2 浓度变化幅度大 ,2 0cm处的浓度时常高出5 0cm处。土下 2 0cm、 5 0cm处CO2 浓度在不同季节的变化趋势是夏季 (32 833× 10 - 6、 386 6 6× 10 - 6)春季 (2 4 4 16× 10 - 6,2 880 0× 10 - 6)秋季 (6 4 5 0× 10 - 6) ,142 16× 10 - 6>冬季 (3833× 10 - 6,8833× - 6) ,土下CO2 浓度变化趋势与温度和降雨量有较好的正相关关系。 2 0cm处的CO2 浓度变化与温度的相关系数r =0 89,与降雨量的相关系数r =0 70 ;5 0cm处的CO2 浓度变化与温度的相关系数r =0 6 9,与降雨量的相关系数r =0 6 6。 (2 )土壤呼吸释放CO2 的速率有类似的变化规律 :夏季为 339 6 8mg m- 2 h- 1、为 2 81 74mg m- 2 h- 1、秋季为 2 0 6 5 9mg m- 2 h- 1、冬季为 6 5 5 3mg m- 2 h- 1。年均排放量为 1 96kg m- 2 yr- 1。 (3)随水排泄HCO3 - 1是岩溶表层泉碳迁移的重要组分。表层泉水的HCO3 - 1浓度的季节变化与气温、月降雨量、土下 2 0cm处CO2浓度存在着负相关 ,其相关系数r =- 0 5 7、  相似文献   

湖南省生态农业试点县生态农业建设回顾与思考   总被引：1，自引：0，他引：1  

彭世良  吴甫成  吕辉红 《热带地理》2001,21(4):315-318

湖南是农业大省，发展生态农业是实现湖南农业可持续发展，振兴湖南农村经济的必然选择，7年来，湖南省5个生态农业试点县（市）生态农业取得了显著的成绩，实现了经济、生态、社会效益的统一和传统农业结构的根本转变；同时积累了丰富的经验，即生态农业建设离不开有关部门的组织与领导、规划和评价体系的制订与实施、高效生态农业模式的建立、科技进步的推动能及资源和生产要素的合理配置。但是湖南省生态农业建设也还存在着一些问题，今后进一步发展应当采取一些得力的措施，如建立健全的调控体系，重视和加强绿色标准化生产，促进农业和产业化、市场化、企业化进程。  相似文献