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环z4+νz4 上负循环码的深度谱 预览
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作者 张光辉 曾广宇 《洛阳师范学院学报》 2019年第2期6-8,共3页
基于有限非链环z4+νz4(v^2=v)上的负循环码与有限链环z4上的负循环码之间的联系,利用z4上的负循环码的深度谱,确定了有限非链环z4+νz4(v^2=v)上偶数长的负循环码的深度谱.
关键词 深度 深度谱 负循环码 z4+νz4 非链环
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An approach to grading coalbed methane resources in China for the purpose of implementing a differential production subsidy
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作者 Liangyu Xia Yujie Yin +1 位作者 Xin Yu Yuhua Zheng 《石油科学:英文版》 SCIE CAS CSCD 2019年第2期447-457,共11页
The heterogeneity of coalbed methane(CBM) resources was not taken into account when the current indiscriminate subsidy policy was developed. In it, limited subsidy funds are given first to high-quality resources and e... The heterogeneity of coalbed methane(CBM) resources was not taken into account when the current indiscriminate subsidy policy was developed. In it, limited subsidy funds are given first to high-quality resources and even to subsidize profitable projects. Thus, the policy has had less than the intended effect in improving CBM production. To implement a new type of differential subsidy, it is necessary to grade the CBM resources, as will be discussed in this paper. After the factors affecting the resources value are systemically examined, sorted and merged, the relationship between the key factors and economic value is analyzed by an engineering economics method, and the production profile type, peak production(or stable production) and buried depth are used as grading factors. The production profile type is used to categorize, and peak production and buried depth are used to grade resources within the same category. The grading method is as follows: use subsidy levels at the economic critical point(NPV = 0) to identify the grades of resources, and determine the combination of peak production and buried depth for different resources grades base on indifference curves drawn according to the relationship between the economic value and peak production and buried depth. 展开更多
关键词 Coalbed methane PRODUCTION profile type Peak PRODUCTION Buried depth DIFFERENTIAL SUBSIDIES
Multivariable regression model for Fox depth correction factor
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作者 Ravi Kant MITTAL Sanket RAWAT Piyush BANSAL 《结构与土木工程前沿:英文版》 EI CSCD 2019年第1期103-109,共7页
This paper presents a simple and efficient equation for calculating the Fox depth correction factor used in computation of settlement reduction due to foundation embedment.Classical solution of Boussinesq theory was u... This paper presents a simple and efficient equation for calculating the Fox depth correction factor used in computation of settlement reduction due to foundation embedment.Classical solution of Boussinesq theory was used originally to develop the Fox depth correction factor equations which were rather complex in nature.The equations were later simplified in the form of graphs and tables and referred in various international code of practices and standard texts for an unsophisticated and quick analysis.However,these tables and graphs provide the factor only for limited values of the input variables and hence again complicates the process of automation of analysis.Therefore,this paper presents a non-linear regression model for the analysis of effect of embedment developed using "IBM Statistical Package for the Social Sciences" software.Through multiple iterations,the value of coefficient of determination is found to reach 0.987.The equation is straightforward,competent and easy to use for both manual and automated calculation of the Fox depth correction factor for wide range of input values.Using the developed equation,parametric study is also conducted in the later part of the paper to analyse the extent of effect of a particular variable on the Fox depth factor. 展开更多
关键词 SETTLEMENT EMBEDMENT FOX DEPTH correction FACTOR regression MULTIVARIABLE
A study of intra-seasonal variations in the subsurface water temperatures in the South China Sea 预览
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作者 Zhan Lian Baonan Sun +2 位作者 Zexun Wei Yonggang Wang Xinyi Wang 《海洋学报:英文版》 SCIE CAS CSCD 2019年第4期97-105,共9页
Through analysis of the results of a verified high-fidelity numerical model,the intra-seasonal variations(ISVs)in the depth of the 22℃ isotherm(D22)in the South China Sea(SCS)basin are investigated.The results show t... Through analysis of the results of a verified high-fidelity numerical model,the intra-seasonal variations(ISVs)in the depth of the 22℃ isotherm(D22)in the South China Sea(SCS)basin are investigated.The results show that the ISVs in the D22 exhibit distinct seasonality in the SCS.The ISVs in the D22 are quite significant,especially within a band along the northwestern boundary of the basin and at the southern end of the basin during boreal winter.In these areas,the ratio of the standard deviations(STDs)of intra-seasonal band to the STDs of total data could exceed 0.6.Although the ISVs in the D22 are detectable in the area affected by the Vietnam Offshore Current during boreal summer and autumn,these variations are sometimes overwhelmed by oscillations with other frequencies.An analysis of the causes of the ISVs in the D22 in the SCS indicates that sea surface fluxes and wind stirring are not the dominant external driving mechanisms of the phenomena described above.The ISVs in the D22 are thought to be induced mainly by the thermodynamic adjustment of the ocean itself and the associated instabilities.The energy of the northern and southern bands that display strong ISVs in the D22 may be derived from eddy kinetic energy,rather than eddy available potential energy.The diversity of the propagation of the ISVs in the D22 is very conspicuous within these two bands. 展开更多
关键词 intra-seasonal VARIATIONS depth of 22℃ ISOTHERM South China Sea
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“死层”掺杂浓度和厚度对太阳能电池性能的影响 预览
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作者 林星星 杨党强 《上海电机学院学报》 2019年第1期1-5,共5页
通过金属辅助化学刻蚀及碱修饰方法制备纳米结构多晶硅太阳能电池,按照“死层”模型运用PC1D模拟软件拟合样品的内量子效率曲线。以“死层”掺杂浓度和厚度变化,分析“死层”结构参数对纳米结构多晶硅太阳能电池的内量子效率曲线、开路... 通过金属辅助化学刻蚀及碱修饰方法制备纳米结构多晶硅太阳能电池,按照“死层”模型运用PC1D模拟软件拟合样品的内量子效率曲线。以“死层”掺杂浓度和厚度变化,分析“死层”结构参数对纳米结构多晶硅太阳能电池的内量子效率曲线、开路电压、短路电流和电池效率的影响。研究表明,当掺杂浓度减少到与第2层发射区相同时,拟合电池效率可达18.10%,比样品电池效率提高0.35%;当“死层”厚度变为0时,拟合电池效率可达18.31%,比样品电池效率提高0.56%。 展开更多
关键词 纳米结构 多晶硅太阳能电池 死层模型 掺杂浓度 厚度
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Retrieval of Snow Depth on Sea Ice in the Arctic Using the FengYun-3B Microwave Radiation Imager 预览
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作者 LI Lele CHEN Haihua GUAN Lei 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第3期580-588,共9页
Snow on sea ice is a sensitive indicator of climate change because it plays an important role regulating surface and near surface air temperatures. Given its high albedo and low thermal conductivity, snow cover is con... Snow on sea ice is a sensitive indicator of climate change because it plays an important role regulating surface and near surface air temperatures. Given its high albedo and low thermal conductivity, snow cover is considered a key reason for amplified warming in polar regions. This study focuses on retrieving snow depth on sea ice from brightness temperatures recorded by the Microwave Radiation Imager(MWRI) on board the FengYun(FY)-3 B satellite. After cross calibration with the Advanced Microwave Scanning Radiometer-EOS(AMSR-E) Level 2 A data from January 1 to May 31, 2011, MWRI brightness temperatures were used to calculate sea ice concentrations based on the Arctic Radiation and Turbulence Interaction Study Sea Ice(ASI) algorithm. Snow depths were derived according to the proportional relationship between snow depth and surface scattering at 18.7 and 36.5 GHz. To eliminate the influence of uncertainties in snow grain sizes and sporadic weather effects, seven-day averaged snow depths were calculated. These results were compared with snow depths from two external data sets, the IceBridge ICDIS4 and AMSR-E Level 3 Sea Ice products. The bias and standard deviation of the differences between the MWRI snow depth and IceBridge data were respectively 1.6 and 3.2 cm for a total of 52 comparisons. Differences between MWRI snow depths and AMSR-E Level 3 products showed biases ranging between-1.01 and-0.58 cm, standard deviations from 3.63 to 4.23 cm, and correlation coefficients from 0.61 to 0.79 for the different months. 展开更多
关键词 MWRI AMSRE BRIGHTNESS temperature SNOW depth inter-sensor calibration sea ice concentration
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A new global ocean hydrographic climatology 预览
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作者 GOURETSKI Viktor 《大气和海洋科学快报:英文版》 CSCD 2019年第3期226-229,共4页
This report describes the main features of the recently published World Ocean Experiment–Argo Global Hydrographic Climatology. This climatology is based on profile data from ships, Argo floats, and sensors attached t... This report describes the main features of the recently published World Ocean Experiment–Argo Global Hydrographic Climatology. This climatology is based on profile data from ships, Argo floats, and sensors attached to marine mammals. As an important deviation from the widely used climatologies produced previously by the National Oceanographic Data Center, the spatial interpolation was performed on local potential density surfaces, so that no ‘artificial water masses’ were created. In addition to monthly fields of temperature and salinity, gridded maps of the upper mixed layer depth are now provided. 展开更多
关键词 Global OCEAN CLIMATOLOGY INTERPOLATION method UPPER MIXED layer DEPTH
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The Assessment of Vocabulary Revisited 预览
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作者 戚宏波 《海外英语》 2019年第1期46-50,共5页
This article reviews the literature in the field of vocabulary assessment especially that since the 1990s.Starting from the construct of vocabulary,which includes definitions of word and lexical item,and the connotati... This article reviews the literature in the field of vocabulary assessment especially that since the 1990s.Starting from the construct of vocabulary,which includes definitions of word and lexical item,and the connotations of knowing a word,it then reviews mainstream methods for the assessment of vocabulary,featured by the studies in the testing of vocabulary breadth and depth.After pointing out the problems and issues in the assessment of vocabulary,it proposes some suggestions which intend to shed some light to the future development of vocabulary testing. 展开更多
关键词 VOCABULARY KNOWLEDGE VOCABULARY ASSESSMENT VOCABULARY BREADTH VOCABULARY DEPTH VOCABULARY TESTING
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Effect of biological activated carbon filter depth and backwashing process on transformation of biofilm community
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作者 Wanqi Qi Weiying Li +3 位作者 Junpeng Zhang Xuan Wu Jie Zhang Wei Zhang 《中国环境科学与工程前沿:英文版》 SCIE EI CAS CSCD 2019年第1期159-169,共11页
The biological activated carbon (BAC) is a popular advanced water treatment to the provision of safe water supply. A bench-scale device was designed to gain a better insight into microbial diversity and community stru... The biological activated carbon (BAC) is a popular advanced water treatment to the provision of safe water supply. A bench-scale device was designed to gain a better insight into microbial diversity and community structure of BAC biofilm by using high-throughput sequencing method. Both samples of BAC biofilm (the first, third and fifth month) and water (inlet water and outlet water of carbon filter, outlet water of backwashing) were analyzed to evaluate the impact of carbon filter depth, running time and backwash process. The results showed that the microbial diversity of biofilm decreased generally with the increase of carbon filter depth and biofilm reached a steady-state at the top layer of BAC after three months' running. Proteobacteria (71.02%-95.61%) was found to be dominant bacteria both in biofilms and water samples. As one of opportunistic pathogen, the Pseudomonas aeruginosa in the outlet water of device (1.20%) was about eight times higher than that in the inlet water of device (0.16%) at the genus level after five-month operation. To maintain the safety of drinking water, the backwash used in this test could significantly remove Sphingobacteria (from 8.69% to 5.09%, p < 0.05) of carbon biofilm. After backwashing, the operational taxonomic units (OTUs) number and the Shannon index decreased significantly (p <0.05) at the bottom of carbon column and we found the Proteobacteria increased by about 10% in all biofilm samples from different filter depth. This study reveals the transformation of BAC biofilm with the impact of running time and backwashing. 展开更多
关键词 Biological activated CARBON BIOFILM COMMUNITY structure CARBON filter DEPTH HIGH-THROUGHPUT SEQUENCING
An integrated method of selecting environmental covariates for predictive soil depth mapping 预览
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作者 LU Yuan-yuan LIU Feng +2 位作者 ZHAO Yu-guo SONG Xiao-dong ZHANG Gan-lin 《农业科学学报:英文版》 SCIE CAS CSCD 2019年第2期301-315,共15页
Environmental covariates are the basis of predictive soil mapping.Their selection determines the performance of soil mapping to a great extent,especially in cases where the number of soil samples is limited but soil s... Environmental covariates are the basis of predictive soil mapping.Their selection determines the performance of soil mapping to a great extent,especially in cases where the number of soil samples is limited but soil spatial heterogeneity is high.In this study,we proposed an integrated method to select environmental covariates for predictive soil depth mapping.First,candidate variables that may influence the development of soil depth were selected based on pedogenetic knowledge.Second,three conventional methods(Pearson correlation analysis(PsCA),generalized additive models(GAMs),and Random Forest(RF))were used to generate optimal combinations of environmental covariates.Finally,three optimal combinations were integrated to produce a final combination based on the importance and occurrence frequency of each environmental covariate.We tested this method for soil depth mapping in the upper reaches of the Heihe River Basin in Northwest China.A total of 129 soil sampling sites were collected using a representative sampling strategy,and RF and support vector machine(SVM)models were used to map soil depth.The results showed that compared to the set of environmental covariates selected by the three conventional selection methods,the set of environmental covariates selected by the proposed method achieved higher mapping accuracy.The combination from the proposed method obtained a root mean square error(RMSE)of 11.88 cm,which was 2.25–7.64 cm lower than the other methods,and an R~2 value of 0.76,which was 0.08–0.26 higher than the other methods.The results suggest that our method can be used as an alternative to the conventional methods for soil depth mapping and may also be effective for mapping other soil properties. 展开更多
关键词 ENVIRONMENTAL COVARIATE selection integrated method PREDICTIVE SOIL MAPPING SOIL depth
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Local scour around two side-by-side cylindrical bridge piers under ice-covered conditions 预览
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作者 Mohammad reza Namaee Jueyi Sui 《国际泥沙研究:英文版》 SCIE 2019年第4期355-367,共13页
In the current study, 108 flume experiments with non-uniform, cohesionless sediments have been done to investigate the local scour process around four pairs of side-by-side bridge piers under both open channel and ice... In the current study, 108 flume experiments with non-uniform, cohesionless sediments have been done to investigate the local scour process around four pairs of side-by-side bridge piers under both open channel and ice-covered flow conditions. Similar to local scour around bridge piers under open channel conditions and a single bridge pier, it was observed in the experiments that the maximum scour depth always occurred at the upstream face of the pier under ice-covered conditions. Further, the smaller the pier size and the greater the spacing distance between the bridge piers, the weaker the horseshoe vortices around the bridge piers, and, thus, the shallower the scour holes around them. Finally, empirical equations were developed to estimate the maximum scour depth around two side-by-side bridge piers under both open channel and ice-covered flow conditions. 展开更多
关键词 Bridge PIER Local SCOUR Maximum SCOUR DEPTH NON-UNIFORM sediment ROUGHNESS of COVER SCOUR pattern
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锦屏深部大理岩蠕变特性及分数阶蠕变模型 预览
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作者 许多 吴世勇 +5 位作者 张茹 张泽天 周济芳 邓建辉 任利 吴斐 《煤炭学报》 EI CAS CSCD 北大核心 2019年第5期1456-1464,共9页
为保障锦屏地下实验室(CJPL)硐室群的长期稳定性,开展2400m深埋大理岩蠕变特性的研究,在常规三轴压缩试验的基础上进行分级加载蠕变试验,系统分析了大理岩蠕变过程中的轴向与环向变形规律及不同围压(5MPa和64MPa)下大理岩蠕变特征差异,... 为保障锦屏地下实验室(CJPL)硐室群的长期稳定性,开展2400m深埋大理岩蠕变特性的研究,在常规三轴压缩试验的基础上进行分级加载蠕变试验,系统分析了大理岩蠕变过程中的轴向与环向变形规律及不同围压(5MPa和64MPa)下大理岩蠕变特征差异,采用等时应力-应变曲线法确定了大理岩的长期强度,并基于分数阶导数改进了大理岩蠕变模型。研究表明:13,27MPa围压下,大理岩轴向应力应变曲线达到峰值应力后快速跌落,40,53,64MPa围压下,峰值应力附近的应变曲线呈现明显的平台段,表明CJPL深部大理岩变形行为随着围压的增加具有由脆性向延性转化的趋势;无论是低围压还是高围压,相比于低应力水平,高应力水平下大理岩更容易发生蠕变变形且环向蠕变现象更加显著,蠕变过程中的扩容现象也更加明显,试样破坏时64MPa围压条件下的体积蠕变变形为5MPa围压下的16.3倍;在蠕变加载过程中,大理岩变形模量均为先增加后减小。变形模量增加阶段,高围压下增加幅度较低围压小,64MPa围压下试样变形模量增加的幅值为1.8GPa,小于5MPa围压下的3.6GPa,表明试样受高围压作用已经部分压密。随着应力水平的增大,变形模量减小,高围压下减小幅度较低围压更大,围压64MPa下试样变形模量减小幅值为9.4GPa,约为峰值变形模量的22%,围压5MPa下试样减小幅值仅为1.8GPa,约为峰值变形模量的4%,表明高围压试样在破坏前裂纹的产生和扩展更为剧烈,岩石劣化程度更大;相同偏应力条件下,围压越大的试样蠕变速率越小,但破坏时变形更大且扩容现象显著,表明相同外荷载条件下,深部围岩赋存环境应力水平较高,变形难以收敛,易发生时效大变形破坏;围压为5,64MPa时,采用等时应力-应变曲线法确定大理岩长期强度分别为170,290MPa,为相应围压三轴压缩强度的82%,73%;基于分数阶导数,改进了大理岩黏弹塑性损伤蠕� 展开更多
关键词 深部 大理岩 蠕变 长期强度 分数阶导数
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Bank gully extraction from DEMs utilizing the geomorphologic features of a loess hilly area in China
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作者 Xin YANG Jiaming NA +2 位作者 Guoan TANG Tingting WANG Axing ZHU 《地球科学前沿:英文版》 SCIE CAS CSCD 2019年第1期151-168,共18页
As one of most active gully types in the Chinese Loess Plateau,bank gullies generally indicate soil loss and land degradation.This study addressed the lack of detailed,large scale monitoring of bank gullies and propos... As one of most active gully types in the Chinese Loess Plateau,bank gullies generally indicate soil loss and land degradation.This study addressed the lack of detailed,large scale monitoring of bank gullies and proposed a semi-automatic method for extracting bank gullies,given typical topographic features based on 5 m resolution DEMs.First,channel networks,including bank gullies,are extracted through an iterative channel bum-in algorithm.Second,gully heads are correctly positioned based on the spatial relationship between gully heads and their corresponding gully shoulder lines.Third,bank gullies are distinguished from other gullies using the newly proposed topographic measurement of "relative gully depth (RGD)."The experimental results from the loess hilly area of the Linjiajian watershed in the Chinese Loess Plateau show that the producer accuracy reaches 87.5%. The accuracy is affected by the DEM resolution and RGD parameters,as well as the accuracy of the gully shoulder line.The application in the Madigou watershed with a high DEM resolution validated the duplicability of this method in other areas.The overall performance shows that bank gullies can be extracted with acceptable accuracy over a large area,which provides essential information for research on soil erosion,geomorphology,and environmental ecology. 展开更多
关键词 BANK GULLY DEMS topographic FEATURES LOESS SHOULDER line relative GULLY depth
小场景交互式稠密三维重建系统 预览
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作者 杨淑云 刘永春 《图学学报》 CSCD 北大核心 2019年第2期364-372,共9页
近年来,随着GPU技术的深入发展和并行算法的日益成熟,使得实时三维重建成为可能。文中实现了一种针对小场景的交互式稠密三维重建系统,此系统借助先进的移动跟踪技术,可以准确地估计相机的即时位置。提出了一种改进的多视深度生成算法,... 近年来,随着GPU技术的深入发展和并行算法的日益成熟,使得实时三维重建成为可能。文中实现了一种针对小场景的交互式稠密三维重建系统,此系统借助先进的移动跟踪技术,可以准确地估计相机的即时位置。提出了一种改进的多视深度生成算法,在GPU加速下能够实时计算场景的深度。改进算法中的亚像素级的半全局匹配代价累积提高了多视立体匹配的精度,并结合全局优化的方法计算出了准确的场景深度信息。深度图被转换为距离场,使用全局优化的直方图压缩融合算法和并行的原始对偶算法实现了深度的实时融合。实验结果证明了重建系统的可行性和重建算法的正确性。 展开更多
关键词 重建 实时 并行算法 深度图 融合
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陕西省恒温层深度主要影响因素及其估算 预览
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作者 周阳 张卉 +3 位作者 江星辰 许泽润 王克 穆根胥 《中国地质调查》 2019年第3期81-86,共6页
恒温层深度的预测与地热能开发利用、地下空间建设等密切相关,陕西省区域恒温层的研究工作进展较慢。通过探讨恒温层深度的影响因素认为:导热系数与恒温层深度呈弱负相关;地表与大气间表面传热系数与恒温层深度呈弱正相关;大气温度年振... 恒温层深度的预测与地热能开发利用、地下空间建设等密切相关,陕西省区域恒温层的研究工作进展较慢。通过探讨恒温层深度的影响因素认为:导热系数与恒温层深度呈弱负相关;地表与大气间表面传热系数与恒温层深度呈弱正相关;大气温度年振幅与恒温层深度呈正相关;导温系数与恒温层深度呈明显的正相关。介绍并验证了一种土壤恒温层深度的计算方法,通过该方法,计算了全省不同地貌单元恒温层深度的理论值。全省恒温层深度介于10.5~23.8m之间:陕北地区恒温层深度为10.5~23.8m;关中盆地恒温层深度为11~17.4m;陕南地区恒温层深度为11.7~18.6m。该研究系统地划分了陕西省区域恒温层的深度范围,为陕西省“绿色”追赶超越政策的实施做出贡献。 展开更多
关键词 恒温层 导温系数 数理统计 深度 陕西省
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Experimental Study on the Hydrodynamic Characteristics of a Submersible Fish Cage at Various Depths in Waves 预览
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作者 LIU Shengcong BI Chunwei +3 位作者 YANG Hui HUANG Liuyi LIANG Zhenlin ZHAO Yunpeng 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第3期701-709,共9页
Submersible fish cages can be submerged under the water to mitigate the negative effects that arise from severe sea conditions and improve the growing environment for the farmed fish. Thus they are increasingly applie... Submersible fish cages can be submerged under the water to mitigate the negative effects that arise from severe sea conditions and improve the growing environment for the farmed fish. Thus they are increasingly applied in offshore aquaculture. To ensure both safety and economic efficiency of submersible fish cages, it is important to determine the optimum submergence depth. In this study, a series of physical model experiments were conducted to investigate the hydrodynamic performance of a submersible fish cage at various submergence depths(1/6, 1/4, 1/3, and 1/2 of the water depth as well as the floating condition for reference) with a model scale of 1:20. The results of the physical model experiment for the different depths were compared to analyze the effects of submergence depths on the mooring line tension and the movement of the floating collar. The results showed that the mooring line tension and the floating collar movement significantly attenuated with increasing submergence depth. However, the attenuation tendency became stable when the fish cage reached a certain depth. According to the results, 1/3 of water depth was determined as the optimal submergence depth of the fish cages. Deeper submergence depths showed no significant advantage from a perspective of the hydrodynamic characteristics of the fish cage. The determination of the optimum submergence depth is beneficial for the structural design and operation safety of submersible net cages. 展开更多
关键词 SUBMERSIBLE fish CAGE HYDRODYNAMIC characteristics SUBMERGENCE DEPTH model experiment
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以政治建设为统领,推动全面从严治党向纵深发展——以天津科技大学为例 预览
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作者 邢军 宋思涛 《中国轻工教育》 2019年第2期5-9,20共6页
旗帜鲜明讲政治,是我们党作为马克思主义政党的根本要求,也是我们党长期坚持的优良传统。高校负有培养中国特色社会主义合格建设者和可靠接班人的重任,坚持以政治建设为统领,推动全面从严治党向纵深发展是高校当前和今后党建工作的重大... 旗帜鲜明讲政治,是我们党作为马克思主义政党的根本要求,也是我们党长期坚持的优良传统。高校负有培养中国特色社会主义合格建设者和可靠接班人的重任,坚持以政治建设为统领,推动全面从严治党向纵深发展是高校当前和今后党建工作的重大课题。文章梳理了高校在全面从严治党方面存在的问题和原因,探寻了解决问题的对策和路径,为高校增强党内政治生活的政治性、时代性、原则性、战斗性,涵养风清气正政治生态,进而推进高校全面从严治党向纵深发展提供了理论支持和方法论支持。 展开更多
关键词 政治建设 从严治党 纵深
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Influences of coarse grid selection on Kirchhoff beam migration 预览
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作者 LI Jiabin SUN Hui +2 位作者 ZHANG Zhihou HAN Fuxing LIU Minchen 《世界地质:英文版》 2019年第1期29-35,共7页
Kirchhoff beam migration is a beam migration method, which focuses on rapid imaging of geological structures. Although this imaging method ignores the amplitude information in the calculation process, it can calculate... Kirchhoff beam migration is a beam migration method, which focuses on rapid imaging of geological structures. Although this imaging method ignores the amplitude information in the calculation process, it can calculate multi-arrival traveltime. This migration method takes into account both imaging accuracy and computational efficiency. Kirchhoff beam migration employs coarse grid techniques in several key steps such as traveltime calculation, weight function calculation, and imaging calculation. The selection of the coarse mesh size has an important influence on the computational efficiency and imaging accuracy of the migration imaging method. This paper will analyze this influence and illustrate the analysis results by the Marmousi data sets. 展开更多
关键词 KIRCHHOFF BEAM MIGRATION PRESTACK depth MIGRATION coarse GRID SELECTION BEAM propagator traveltime calculation
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Impact of geo technical factors on strata behavior in longwall panels of Godavari Valley coal field-a case study 预览
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作者 Veera Reddy Boothukuri Ram Madhav Bhattacharjee +1 位作者 Durga Charan Panigrahi Gautam Benerjee 《矿业科学技术学报:英文版》 CSCD 2019年第2期335-341,共7页
Understanding the cantilevers formed by thick,massive beds in the near-seam overburden above longwall panels and the associated loads and strata fracturing effects developed during caving(main and periodic weightings)... Understanding the cantilevers formed by thick,massive beds in the near-seam overburden above longwall panels and the associated loads and strata fracturing effects developed during caving(main and periodic weightings)are key elements for the successful implementation of longwalls.Such caving mechanisms rely on the geotechnical conditions within the panel.In India,the majority of longwall downtime and/or roof failures were caused by a lack of knowledge on overburden caveability,in particular when the main and periodic weightings will impact the face and longwall support selection to effectively mitigate such weightings.Godavari Valley Coal Fields is no exception as longwall faces were adversely affected due to the presence of thick,massive beds in the near-seam overburden at both Godavarikhani(GDK)7 and 9 Incline mines.In contrast,overburden weightings were negotiated successfully in GDK10A and Adriyala Longwall Project(ALP)mines by detailed geotechnical studies,the use of adequate longwall support capacities,and effective operational practices.Thirteen longwall panels with varying face width,at different depths have been extracted under massive sandstone beds of 18m to 28m thickness at GDK 10A and ALP mines.This study elucidates that the main roof weighting interval decreases with an increase in face width and attains a constant value with further increases in face width under the same geo-mining conditions.In addition,this study also concludes that with increases in face width,the periodic roof weighting interval decreases and shield loads increase.Similarly with increasing panel width to depth ratio,the main and periodic roof weighting intervals decrease but shield loads again increase.Lastly,the strata behaviour of the longwall face retreated along up-dip direction is demonstrated.The results of this paper improves the mechanistic understanding of the impact of face width,depth and main roof thickness on periodic weighting and associated roof control problems on the longwall face. 展开更多
关键词 LONGWALL mining ROOF weightings INTERVALS SHIELD loadings Face WIDTH Cover depth
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永靖县深度贫困地区富民产业发展现状 预览
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作者 王有娟 陈克青 《畜牧兽医杂志》 2019年第2期42-44,共3页
为进一步加快我县深度贫困地区产业提升工程工作进度,做大做强县域经济,培育发展富民产业,着力促进农民增收,坚决打赢深度贫困地区脱贫攻坚战,我县提出深度贫困地区富民产业——肉牛肉驴百合的发展。
关键词 深度 贫困地区 产业提升 富民产业
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