共查询到20条相似文献，搜索用时 31 毫秒
1.
Yu Chuxin Xian Xuefu Tan Xueshu 《保鲜与加工》1989,(5):1-10
This paper analyzes comprehensively the present approaches about the flow theory and governing equation of the gas seepage in China from the equations of the gas flow continuity, motion, state ane content. The viewpoint is put forward in the paper that the gas amount taking part in seepage flow is only a part of the whole gas content. The governing equation, of gas seepage flow in coal seams is set up on condition that procedures of adsorption and desorption are convertible completely. 相似文献
2.
Moisture dependent root sink function developed by F eddes et al. (1976) which incorporates linearly varying moisture availability proposal between field capacity and wilting point was embedded in the continuity equation for transient moisture flow in conjunction with Darcy's law and moisture contents in a homogeneous soil profile under wheat cropped condition were simulated numerically using implicit finite difference scheme. Simulated moisture contents were observed to be reasonably in good agreement with the observed moisture contents as the variations between the simulated and observed values varied from 2.97 to 21.76 percent. 相似文献
3.
Follow in precursory relating documents, several equations of one dimension Large Strain Consolidation (LSC) and consolidation coefficients were discussed firstly. Based on this, a Finite Difference Method (FDM) equation was derived, which was the physical described LSC equation with variable displacement. Moreover, the initiate and boundary condition were dispersed by FDM, and the boundary of different layers of super soft soil was disposed of continuity. Finally,nonlinear group equations of LSC FDM solution was deduced for multi layers super soft ground by repeated method, and a FDM program of 1D nonlinear LSC analysis was compiled. Finally, a case showed a satisfied analysis result by LSCFDM. 相似文献
4.
To overcome the detection difficulties of the surface defects when milling a hot heavy rail,a suite of detection system for on-line surface defect is developed. To select optical environment according to radiation of heavy rail and characteristics of light,use multi-linear array CCD cameras to parallel multi-angle collect images of whole surface of hot heavy rail,and obtain images through an image adaptive preprocessing to meet requirements of defect detection. For the condition that the defects extracting causing by continuity of the surface defects of hot heavy rail is hard to realize through traditional image segmentation, an examining algorithm of image relevance between pixel lines is proposed, using pixel de-differentiation and statistical variance operations to extract defect. This algorithm is demonstrated to be better than traditional edge detection,and the system has achieved good results in the practical application of a rail beam plant. 相似文献
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6.
Bottom continuity tendons induce transverse additive effect while providing longitudinal compression during the construction of PC box girder. Taking a cross-sea bridge for example, the mechanism of bottom continuity tendon is investigated. The transverse effect and parameters study are conducted through a refined model. It is illustrated that the state of bottom flange is in a dynamic changeable process during the tensioning of bottom continuity tendons, and the transverse effect caused by the tendons is much more than that by dead loading and other prestressing tendons. The transverse effect is more sensitive to alignment and thickness of the bottom flange, as well as concrete cover of the ducts. Finally, based on the simplified frame analysis, the design method is proposed by introducing prestressing effect simplified factor and duct modified factor. 相似文献
7.
《Journal of Landscape Research》2017,(1)
Temple of local land god is a kind of traditional sacrificial architecture in China's village,and is cultural landscape generated under special farming system of China,which reflects the spiritual world of the working people and bears the history of the village. Its protection and continuity must take inheriting the cultural spirit as the most important prerequisite,and "place spirit" established by Norberg Schultz provides important theoretic basis for it. In this paper,based on "place spirit","place spirit" of temple of local land god is interpreted,and important role of "place spirit" in its protection and continuity and the ways to create "place spirit" of temple of local land god are explored. 相似文献
8.
R. Gerhards M. Sökefeld D. Knuf W. Kühbauch 《Journal of Agronomy and Crop Science》1996,176(4):259-266
Mapping and geostatistical analysis of weed distribution in sugarbeet fields for site-specific weed management
Field experiments were conducted to study the distribution of weeds in 18 sugarbeet fields of 3 ha each. The distance between each sampling point was 7.5–20 m. Weed density was counted and maps were plotted for the distribution of Chenopodium album and Solanum nigrum using linear interpolation. Geostatistical methods were applied to analyse the variance of weed density between the sampling points. A clear detection of weed patches was possible when the variance of weed density at a single sampling point 'nugget effect' was low and a high continuity between neighbouring grid points existed. If soil conditions or cultivation methods are not homogeneous in the field (drift), no continuity between the sampling points was found. Geostatistical analysis of the weed distribution in agricultural fields provide helpful information for a site-specific weed management. 相似文献
Field experiments were conducted to study the distribution of weeds in 18 sugarbeet fields of 3 ha each. The distance between each sampling point was 7.5–20 m. Weed density was counted and maps were plotted for the distribution of Chenopodium album and Solanum nigrum using linear interpolation. Geostatistical methods were applied to analyse the variance of weed density between the sampling points. A clear detection of weed patches was possible when the variance of weed density at a single sampling point 'nugget effect' was low and a high continuity between neighbouring grid points existed. If soil conditions or cultivation methods are not homogeneous in the field (drift), no continuity between the sampling points was found. Geostatistical analysis of the weed distribution in agricultural fields provide helpful information for a site-specific weed management. 相似文献
9.
气象台站迁址历史观测资料三性分析 总被引：1，自引：0，他引：1
利用莘县国家基准气候站、冠县国家一般气象站、茌平国家一般气象站作为参考站,采用差值比较、线性趋势、相关系数、均一性t检验方法,对拟迁站聊城国家一般站1961—2013年的年平均气温、年降水量、年平均相对湿度和年平均风速进行观测资料序列完整性、区域一致性和均一性分析。结果表明：（1）聊城站现址气象要素月年缺测率为0%,观测资料完整性好。（2）气温区域一致性较好;降水由于存在局地性,区域一致性一般;受站址变动和气象探测环境变化的影响,2003年以后现址风速、相对湿度区域一致性较差。（3）年平均气温为序列连续,年降水量和年平均相对湿度连续性较好,年平均风速连续性较差,站址变动及站址周围逐渐长高长大的树木是影响该站现址观测资料均一性的主要原因。 相似文献
10.
高中化学"新课改"已经在全国范围展开,其模块化改革模式使得不同省份或同省不同地区高中毕业生化学知识存在差异。因此,大学基础化学教学有必要在了解"新课改"的基础上,进行在教育设计、教学方式、教学内容、考核模式等方面进行改革,以充分实现"新课改"下的高中化学与大学基础化学课程学习的有效衔接,保证化学课程学习体系的延续性和统一性。 相似文献
11.
Arc approximation method is widely used in machining those parts contoured by various complex plane curves. In this paper, several arc approximation methods are reviewed, and the algorithm of the optimum arc approximation, which ensures the continuity of derivatives, is established. The algorithm presented can be used to precisely machine the parts with complex plane curves and the revolving body with a curved surace. In addition, it can also be used in part-programming of CNC machining. 相似文献
12.
为提高大规模品种试验的精确度，根据田间上土壤肥力连续原理，建立随机区组设计的一阶，二阶差分近邻小区模型，利用修饰极大似然法估计参数，相对于常规的方差分析，在误差模型与局控制方面作了改进，从而进一步控制了区组内小区异的异质性。 相似文献
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Luzhou is a famous wine country and a historical city in P. R. China. Insuring the continuity of urban context is an effective method for creating a distinctive image of a city. Considering the authenticity, sustainable development, enforceability and regional differences of urban contexts, it is an appropriate way to extract the original urban context and adopt a proper design method that combines humanized nature, material culture, and intangible culture to form an area with cultural atmosphere on both banks of the Tuojiang River. 相似文献
14.
Based on an analyses to the characteristics of operation of synchronous motor being out of step,and its harmfulness with the help of computers. Some protection measures have been presented here. These protecting measures to be taken can make a motor contin ually running with load while the motor is out of step,at the same time the synchronization of the moter can be restored itself.This can not only avoid harms because of motor being out of step but also guarante the continuity production procedure. 相似文献
15.
农业自主创新环境评价的影响因素研究——以天津市调查为例 总被引：2，自引：1，他引：1
创新环境是区域、产业、企业的创新成果的直接孵化基地,良好的农业创新环境是农业自主创新活动有序、高效、持续进行的有力保障。笔者从农业科技人员感知角度出发,通过天津市科技人员的抽样调查,运用描述性统计学分析和逐步多元回归分析的方法,找出创新环境中存在的问题和影响科技人员对创新环境总体评价的关键因素。结果表明,激励制度、试验基地条件、科研团队结构是影响科技人员自主创新的关键因素,示范基地的条件、科研经费投入、职称评定制度是影响科技人员自主创新的重要因素。 相似文献
16.
Abrasive water jets can incise objects with strong rigidity under water. The analytical means of kinetic theory is optimal for theoretical problems of submerged abrasive water jets. The flow characteristics in submerged abrasive water jets were analyzed based on kinetic theory for multiphase flows. The impact characteristics of every phase in submerged abrasive water jets was analyzed and continuity and momentum equations subsequently were developed for solid, gas and liquids in submerged abrasive water jets. It is shown that if the distributing function of every phase were given, the law of its movement could be ascertained. 相似文献
17.
An analytical solution of the elastic circular plate on multi layered soil can be obtained by using the transfer matrix solutions for displacements and stresses of multi layered soil. This solution is based on the continuity of vertical displacements and the smooth contact conditions between a multi layered soil surface and the elastic circular plate. Numerical calculation and analysis are carried out by the computer program compiled for this purpose. The numerical results show that the rigidity of the elastic circular plate greatly influences the displacement of the circular plate and the normal stresses under the center of the circular plate. 相似文献
18.
不同抗性品种对棉花黄萎病菌致病力的影响 总被引：1，自引：0，他引：1
以1个海岛棉品种和15个陆地棉品种为分离寄主,采取单孢分离,共分离出67个黄萎病菌系。以抗性差异较大的海岛棉品种Pima90-53和陆地棉品种冀棉20、邯208和中棉所8号为鉴别寄主,采用苗期营养钵定量注菌液法对分离菌系进行了致病力鉴定。结果表明,同一地块田间不同品种所分离菌系的致病力类型并非单一类型,而是由致病力连续变化的多种致病力菌系类型组成;由不同品种分离出的菌系致病力存在差异,寄主品种的抗性与分离的黄萎病菌系的致病力无关,但不同基因型品种可能会影响不同致病力菌落的消长。 相似文献
19.
《Journal of Landscape Research》2013,(Z3)
The concept of urban green space system planning was proposed after analyzing the background of compiling Guangzhou green space system planning and current situation of local green spaces,i.e. design landscape pattern of Guangzhou City during urban agglomeration of the Pearl River Delta,and highlight Lingnan cultures(Lingnan refers to south of the Five Ridges) and features of "Flower City"(another name of Guangzhou). Key points of planning are protecting ecological barriers in the north,improving urban garden structure in the center,using wetland reasonably in the south,to maintain integrality and continuity of the landscape pattern. 相似文献
20.
There are more than one measure devices during the craft launching proceeding, reliable craft orbit measurement selection is important for launching monitor and safety control. This paper proposes a novel orbit selection method by knowledge based neural network, which combines the human knowledge and orbit samples based training together. The false spur orbit data are deleted according the data continuity rule at first, then the difference between orbit data is computed, and at last a neural network is trained to test reliability of each data and select the orbit with high precision among all orbit data. Simulations and experiments show the efficiency and reliability of our method. 相似文献