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Seedling potential of trees species along the elevational gradient in temperate hill forest of central Nepal
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作者 DANI Ram Sharan BANIYA Chitra Bahadur 《Journal of Mountain Science》 SCIE CSCD 2024年第4期1329-1344,共16页
Regeneration status of tree species along elevation gradient in temperate hill forest was not understood greatly.Present research examined the tree diversity and its regeneration patterns along an elevation gradient i... Regeneration status of tree species along elevation gradient in temperate hill forest was not understood greatly.Present research examined the tree diversity and its regeneration patterns along an elevation gradient in temperate hill forest,central Nepal.Data were collected from 300 sample plots within vertical elevation bands of 10,ranging from 1365 to 2450 m asl.A random sampling method was used for data collection in three seasons,winter,pre-monsoon and post monsoon seasons.Diameter at breast height(DBH)was used to broadly categorize the plant individual into trees,saplings and seedlings.The tree species richness ranged from 12 to 25 with density of 350 to 1200 individuals per hectare.Species richness of tree and sapling showed statistically significant unimodal pattern,which peaked at mid-elevation.Elevation showed a strong and positive linear correlation with the seedling density(Deviance=0.99,p<0.001)and a significant hump-shaped relationship with sapling density(Deviance=0.95,p<0.001).Similarly,elevations showed a statistically significant negative hump-shaped relationship with all trees,saplings and seedling stages(Deviances=0.89,0.87 and 0.57).The highest values of the Shannon-Wiener index and the lowest value of the Simpson index were found at mid-elevation for all growth forms.Nearly 92%of tree species were found at regenerating stage;49%in a good renewal regeneration status,32%in fair renewal regeneration,and 11%at a poor regenerating condition.Nevertheless,4%of tree species were reported as non-regenerating stages and 4%were newly introduced species.Hence,the regeneration status of the study area was considered fairly well since sapling(78.5%)>seedling(10.6%)≤mature(10.9%).Among tested environmental variables,elevation and annual mean rainfall were the most influential factors in the regeneration of tree species. 展开更多
关键词 Regeneration potential Chandragiri hill Altitudinal gradient Species diversity Tree species richness
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基于Hill肌肉模型的仿袋鼠腿悬架控制特性研究
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作者 宋勇 刘世静 +2 位作者 李占龙 孟杰 张喜清 《太原科技大学学报》 2023年第5期403-409,共7页
为进一步改善车辆悬架的控制性能,采用仿生设计思想,提出一种基于Hill肌肉模型的仿袋鼠腿悬架(下称仿生悬架)。设计了该悬架的Fuzzy、Fuzzy-PID控制器,并采用ADAMS和Simulink联合仿真对其控制特性开展研究。研究发现:①冲击路面下,相对... 为进一步改善车辆悬架的控制性能,采用仿生设计思想,提出一种基于Hill肌肉模型的仿袋鼠腿悬架(下称仿生悬架)。设计了该悬架的Fuzzy、Fuzzy-PID控制器,并采用ADAMS和Simulink联合仿真对其控制特性开展研究。研究发现:①冲击路面下,相对于被动悬架,Fuzzy控制和Fuzzy-PID控制下的车身位移和车身加速度分别下降了54%、58%和92%、93%,悬架抗冲击性能明显改善。②随机路面下,随着路面等级和车速的增加,Fuzzy控制和Fuzzy-PID控制均可有效改善悬架的控制性能;相对于被动悬架,主动控制下的悬架表现出更加优异的缓冲隔振性能、路面适应性及稳定性;主动控制下的车身加速度传递率(8.8%~1%)呈下降趋势且数值较小,轮胎动位移(0.19~3.92)mm及其传递率(8.1%~10.5%)呈上升趋势,但数值及变化较小。③冲击路面和随机路面下,相较于Fuzzy控制,Fuzzy-PID控制下的悬架特性更优。上述结果表明,基于Hill肌肉模型的仿生悬架具有良好的控制特性,验证了该仿生思路和控制方法的正确性和有效性。 展开更多
关键词 悬架 hill肌肉模型 FUZZY控制 FUZZY-PID控制 仿袋鼠腿
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Decipher hydrocarbon generation and accumulation based on fluid inclusion and chronology:A case study from the Upper Paleozoic buried-hills in Huanghua Depression,Bohai Bay Basin
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作者 Li-Hong Zhou Yong Li +5 位作者 Feng-Ming Jin Jin-Feng Xie Xiu-Gang Pu Li-Xin Fu Da Lou Yang Tian 《Petroleum Science》 SCIE EI CAS CSCD 2023年第4期1998-2008,共11页
Deciphering hydrocarbon generation and accumulation stage is of significance to understand oil and gas evolution and seek exploration targets.Taking the Upper Paleozoic buried-hills in the Huanghua Depression,Bohai Ba... Deciphering hydrocarbon generation and accumulation stage is of significance to understand oil and gas evolution and seek exploration targets.Taking the Upper Paleozoic buried-hills in the Huanghua Depression,Bohai Bay Basin,as a case study,hydrocarbon generation environment and detailed accumulation process are revealed by fluid inclusions observations,Laser Raman spectroscopy,Fourier Infrared spectroscopy,and K-Ar isotope measurements.The results show that both oil and gas inclusion were captured in the quartz overgrowth,dissolved feldspar and calcite microfractures,showing blue to dark brown fluoresce.The grains containing oil inclusions index(GOI)of oil,oil&gas and gas being 25%,65%,and 10%and the inclusions with abundant methyl groups and short chains,both indicate high thermal maturity.One series of fluids inclusion is generally observed,evidenced by the concentrated homogenization temperature of 135-145℃ and salinity of 3%-15 w.t.%NaCl equiv,indicating one primary charging stage.The gas and gas&liquid inclusions mainly contain CH_(4),with also peaks indicating CO_(2) and N_(2.)The Carboniferous and Permian biomarkers show reducing environment with brackish water,with organic matter sources both from marine and continental.The relative content ofααα20RC_(27),ααα20RC_(28),andααα20RC_(29) exhibit source contributions both from algae and higher plants,and mainly of II2 to III kerogen.Both coal derived gas and oil associated hydrocarbons are identified from most of the buried-hills.Combining the fluid homogenization temperature and salinity,as well as the thermal evolution history,the hydrocarbon generated from the Upper Paleozoic was concentrated at the end of the Eocene(40 Ma±),while the beginning of charging is 60 Ma±.The Wumaying Buried-hill is of only coal derived gas and has potential for inner coal measure natural gas exploration.The results provide a detailed understanding of hydrocarbon accumulations in the study area,which can also be reference for improving petroleum exploration efficiency in similar basins. 展开更多
关键词 Petroleum accumulation Buried hills K–Ar isotope Fluid inclusions Huanghua depression Bohai Bay Basin
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Hill Matrix and Radix-64 Bit Algorithm to Preserve Data Confidentiality
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作者 Ali Arshad Muhammad Nadeem +6 位作者 Saman Riaz Syeda Wajiha Zahra Ashit Kumar Dutta Zaid Alzaid Rana Alabdan Badr Almutairi Sultan Almotairi 《Computers, Materials & Continua》 SCIE EI 2023年第5期3065-3089,共25页
There are many cloud data security techniques and algorithms available that can be used to detect attacks on cloud data,but these techniques and algorithms cannot be used to protect data from an attacker.Cloud cryptog... There are many cloud data security techniques and algorithms available that can be used to detect attacks on cloud data,but these techniques and algorithms cannot be used to protect data from an attacker.Cloud cryptography is the best way to transmit data in a secure and reliable format.Various researchers have developed various mechanisms to transfer data securely,which can convert data from readable to unreadable,but these algorithms are not sufficient to provide complete data security.Each algorithm has some data security issues.If some effective data protection techniques are used,the attacker will not be able to decipher the encrypted data,and even if the attacker tries to tamper with the data,the attacker will not have access to the original data.In this paper,various data security techniques are developed,which can be used to protect the data from attackers completely.First,a customized American Standard Code for Information Interchange(ASCII)table is developed.The value of each Index is defined in a customized ASCII table.When an attacker tries to decrypt the data,the attacker always tries to apply the predefined ASCII table on the Ciphertext,which in a way,can be helpful for the attacker to decrypt the data.After that,a radix 64-bit encryption mechanism is used,with the help of which the number of cipher data is doubled from the original data.When the number of cipher values is double the original data,the attacker tries to decrypt each value.Instead of getting the original data,the attacker gets such data that has no relation to the original data.After that,a Hill Matrix algorithm is created,with the help of which a key is generated that is used in the exact plain text for which it is created,and this Key cannot be used in any other plain text.The boundaries of each Hill text work up to that text.The techniques used in this paper are compared with those used in various papers and discussed that how far the current algorithm is better than all other algorithms.Then,the Kasiski test is used to verify the validity of the proposed algorithm and found that,if the proposed algorithm is used for data encryption,so an attacker cannot break the proposed algorithm security using any technique or algorithm. 展开更多
关键词 CRYPTOGRAPHY symmetric cipher text ENCRYPTION matrix cipher encoding decoding hill matrix 64-bit encryption
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A Darcy-Law Based Model for Heat and Moisture Transfer in a Hill Cave
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作者 Fei Liu Dongliang Zhang +1 位作者 Qifu Zhu Qingyong Su 《Fluid Dynamics & Materials Processing》 EI 2023年第9期2345-2359,共15页
A hill can be regarded as an environmental carrier of heat.Water,rocks and the internal moisture naturally pre-sent in such environment constitute a natural heat accumulator.In the present study,the heat and moisture ... A hill can be regarded as an environmental carrier of heat.Water,rocks and the internal moisture naturally pre-sent in such environment constitute a natural heat accumulator.In the present study,the heat and moisture trans-fer characteristics in a representative hill cave have been simulated via a method relying on the Darcy’s law.The simulations have been conducted for both steady and unsteady conditions to discern the influence of permeability and geometric parameters on the thermal and moisture transfer processes.The reliability of the simulation has been verified through comparison of the numerical results with the annual observation data.As revealed by the numericalfindings,the internal temperature of the hill accumulator is proportional to the permeability,outside surface temperature,overground height,underground constant temperature layer depth,and underground tem-perature of the hill,and it is inversely proportional to the horizontal size of the hill.Moreover,in the considered case,the order of magnitude of the permeability of the hill is contained in the range 10-15–10-13,and displays a certain sensitivity to the rainwater seepage. 展开更多
关键词 Cave hill thermal and moisture transfer Darcy’s law temperaturefield PERMEABILITY
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Efficient Clustering Using Memetic Adaptive Hill Climbing Algorithm in WSN
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作者 M.Manikandan S.Sakthivel V.Vivekanandhan 《Intelligent Automation & Soft Computing》 SCIE 2023年第3期3169-3185,共17页
Wireless Sensor Networks are composed of autonomous sensing devices which are interconnected to form a closed network.This closed network is intended to share sensitive location-centric information from a source node ... Wireless Sensor Networks are composed of autonomous sensing devices which are interconnected to form a closed network.This closed network is intended to share sensitive location-centric information from a source node to the base station through efficient routing mechanisms.The efficiency of the sensor node is energy bounded,acts as a concentrated area for most researchers to offer a solution for the early draining power of sensors.Network management plays a significant role in wireless sensor networks,which was obsessed with the factors like the reliability of the network,resource management,energy-efficient routing,and scalability of services.The topology of the wireless sensor networks acts dri-ven factor for network efficiency which can be effectively maintained by perform-ing the clustering process effectively.More solutions and clustering algorithms have been offered by various researchers,but the concern of reduced efficiency in the routing process and network management still exists.This research paper offers a hybrid algorithm composed of a memetic algorithm which is an enhanced version of a genetic algorithm integrated with the adaptive hill-climbing algorithm for performing energy-efficient clustering process in the wireless sensor networks.The memetic algorithm employs a local searching methodology to mitigate the premature convergence,while the adaptive hill-climbing algorithm is a local search algorithm that persistently migrates towards the increased elevation to determine the peak of the mountain(i.e.,)best cluster head in the wireless sensor networks.The proposed hybrid algorithm is compared with the state of art clus-tering algorithm to prove that the proposed algorithm outperforms in terms of a network life-time,energy consumption,throughput,etc. 展开更多
关键词 Wireless sensor networks TOPOLOGY CLUSTERING memetic algorithm adaptive hill climbing algorithm network management energy consumption THROUGHPUT
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Petrographic Characteristics and Metalogeny of Zatua Hills BIFs, Haut-Uele Province (DR Congo)
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作者 Levesque Makuku Mbo Papy-Fidèle Kombie Andeibal +3 位作者 François Tshiabo Luwanda Dominique Wetshondo Osomba Valentin Kanda Nkula Albert Ongendangenda Tienge 《Journal of Geoscience and Environment Protection》 2023年第12期163-181,共19页
Zatua Hills are located at Haut Uélé Province of Democratic Republic of Congo (DRC), between northern Bafwasende and southern Paulis (Isiro) Squarred Degrees. Belonging to greenstone belt of Ngayu, that area... Zatua Hills are located at Haut Uélé Province of Democratic Republic of Congo (DRC), between northern Bafwasende and southern Paulis (Isiro) Squarred Degrees. Belonging to greenstone belt of Ngayu, that area is identified by the high elevated zone which is remained the witness of stable zone, not affected by the ancienst erosion process. Zatua Hills are in the superior Kibalian formation dated to Neoarchaen, hosted in Upper Congo Granites Massifs of DRC covering a large central zone of NE of DRC, and consisting to dolerite, phyllade, clay rich sediment, poor Banded Iron Formations (BIFs), enriched BIFs, friable hematite, hard hematite, mineralized and unmineralized brechias. Magnetite, martite and hematite are associated to some secondary minerals such as goethite, gibbsite, kaolinite, strengite, variscite and others clay minerals present in BIFs. Petrographic analysis made from the samples collected in situ showed, as well as BIFs and iron ore associated, that magnetite was much abundant oxide mineral which is oxided to martite before to stabilize to hematite during the deposition time. Having about hundred meters of thickness, the rich iron ore of this area content, in the majority less deleterious elements which, are harmful in metallurgic process of iron. These secondary minerals were precipitated at various degrees in the leached cavities of rocks between martite and hematite aggregates to botryoidal texture and, are rich to Al, and are mainly consisting to gibbsite and solid solution series of variscite-strengite (AlPO<sub>4</sub>·2H<sub>2</sub>O and FePO<sub>4</sub>·2H<sub>2</sub>O). Low degree of metamorphism played when magnetite was converted to martite, with the presence of variscite and anatase like witnesses of this event in which, martite was crystalized to hematite. 展开更多
关键词 BIFs Zatua hills Petrographic DRC Iron Ore
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Geochemical Signature and Metalogeny of BIFs and Associated Iron Ore of Zatua Hills, Haut-Uele Province (DR Congo)
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作者 Levesque Makuku Mbo Dominique Wetshondo Osomba +2 位作者 Valentin Kanda Nkula Kelly Nzambe Keyila Albert Ongendangenda Tshiende 《Journal of Geoscience and Environment Protection》 2023年第10期201-217,共17页
Zatua Hills are located in the northeastern part of the DR Congo in Haut Uélé Province, formerly known as Province Orientale. This part of DR Congo is identified by the high elevated zone, which has rem... Zatua Hills are located in the northeastern part of the DR Congo in Haut Uélé Province, formerly known as Province Orientale. This part of DR Congo is identified by the high elevated zone, which has remained a witness to a stable zone not affected by the ancient erosion process. BIFs are most abundant and are dated to the Neoarchaean and Late Kibalian, hosted in the Upper Congo Granites Massifs of the DR. Congo. Zatua Hills consist of dolerite, phyllade, clay-rich sediment, poor itabirite, enriched BIFs, friable hematite, hard hematite, and mineralized and unmineralized breccias. Field study and geochemistry analysis by XRF, XRD, and ICP-MS are executed in order to know the geochemistry signature and paragenesis of Zatua Hills and the probably process could lead the BIFs to iron ore. The geochemistry analysis by XRF, XRD, and ICP-MS shows that Iron ore content has an iron rate between 57% and 69% with less deleterious elements such as Si, P, and Al. These deleterious elements are secondary and have silicium composition (probably quartz or chert, goethite, and Kaolinite), aluminum (probably gibbsite, variscite, cadwaladérite, goethite, and Kaolinite), phosphorous (probably variscite), and hydrated minerals, which are grown LOI in the samples. Hypogen and supergen processes are played in BIFs for iron ore conversion and, respectively, silica dissolution and leaching. Metamorphism was also impacted and marked by the Ti element (anatase) in samples, contributing to the crystallization of martite to hematite after magnetite oxidation. 展开更多
关键词 BIFs Zatua hills Geochemestry DRC Iron Ore
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Experimental Study on Phase Characteristics of CO2 Injection in BZ13-2 Strong Volatile Oil Reservoir in Bohai Sea Buried Hills
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作者 Zhennan Gao Lei Zhang +2 位作者 Yong Jiang Jingtao Wu Chenxu Yang 《Open Journal of Geology》 2023年第7期763-772,共10页
BZ13-2 oil field is a deep submerged strongly volatile reservoir in Bohai Sea. This oil reservoir has the characteristics of high gas oil ratio and small difference in formation pressure and saturation point pressure.... BZ13-2 oil field is a deep submerged strongly volatile reservoir in Bohai Sea. This oil reservoir has the characteristics of high gas oil ratio and small difference in formation pressure and saturation point pressure. It usually adopts gas injection development to avoid crude oil degassing and fast decreasing production capacity. However, the phase characteristics and miscibility mechanism of this high-temperature and high-pressure fluid after gas injection are not clear. Therefore, it is necessary to study the feasibility of CO<sub>2</sub> injection to improve oil recovery in near critical volatile oil reservoirs through CO<sub>2</sub> injection experiments. In the early stage of the depletion experiment, the content of heavy components in the remaining oil increased significantly, so the depletion method is not conducive to the development of such reservoirs. With the increase of CO<sub>2</sub> injection, the volumetric expansion coefficient of formation crude oil increases significantly, while the saturation pressure and formation crude oil viscosity remain basically unchanged. The minimum miscible pressure experiment shows that CO<sub>2</sub> injection under formation pressure conditions can achieve multiphase miscibility. Based on experimental research results, the BZ13-2 oilfield is suitable for early gas injection development and can significantly improve recovery. 展开更多
关键词 Bohai Buried hills Strongly Volatile Reservoir Gas Injection and Development Phase Characteristics Fine Tube Experiment
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Reconstruction Design of Zaozhuang Gangue Hill Based on the Interaction of“Scenery”and“View”
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作者 CAO Ying LIANG Zhiwei ZHANG Li 《Journal of Landscape Research》 2023年第4期9-16,共8页
Gangue hill is the associated accumulation landscape of long-term coal mining.There are a large number of gangue hills left in coal mining cities,which not only causes ecological damage but also affects the urban envi... Gangue hill is the associated accumulation landscape of long-term coal mining.There are a large number of gangue hills left in coal mining cities,which not only causes ecological damage but also affects the urban environment,thus becoming the focus of urban landscape transformation of coal mining cities.With the increase of people’s demand for ecological leisure,it has become the first choice to transform gangue hill and its surrounding areas into community parks.From the perspective of urban space and landscape system,as a huge regeneration landform in the city and a unique landscape in the mining area,gangue hill not only needs to be afforested,but also needs to be connected with mining heritages and landscape nodes in the city to form the interaction between“scenery”and“view”,so as to form an integrated mining cultural landscape system at the urban level.On the basis of this concept,taking the gangue hill of Zhongxing in Zaozhuang City as an example,this paper quantitatively analyzes the best landscape construction site in the gangue hill via viewshed analysis in GIS.Through this method,the gangue hill and Zhongxing mining heritage are closely combined,so as to establish the interactive relationship between“scenery”and“view”.It can guide the planning and design of sightseeing route and footpath system,and also provide a technical support for the design of community parks transformed from gangue hills. 展开更多
关键词 Gangue hill Zhongxing mining heritage Interaction of“scenery”and“view” Viewshed analysis
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The Awakening of Consciousness:Traumatic Repetition in“Funeral Music”by Geoffrey Hill
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作者 XING Luan-ming 《Journal of Literature and Art Studies》 2023年第9期661-664,共4页
The aftermath of the war had devastating consequences on people’s lives and society as a whole.In addition to the significant impact of the Great Depression on social production and living standards,it resulted in ps... The aftermath of the war had devastating consequences on people’s lives and society as a whole.In addition to the significant impact of the Great Depression on social production and living standards,it resulted in psychological trauma,unemployment,poverty,and social conflicts.As a prominent English poet that emerged after World War II,Geoffrey Hill depicted the gruesome realities of war through his early works.This article applies Cathy Caruth’s trauma theory to analyze Hill’s poem“Funeral Music.”The fragmented images and repetitive traumatic scenes restore the harsh realities of war.Furthermore,this article explores Joshua Pederson’s critical development of Caruth’s theoretical framework,providing an alternate perspective for textual analysis. 展开更多
关键词 TRAUMA Geoffrey hill “Funeral Music” Cathy Caruth Joshua Pederson
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Distributed Trimmed Hill Estimator
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作者 Tao Guo 《Journal of Applied Mathematics and Physics》 2023年第12期4000-4015,共16页
Proceeded from trimmed Hill estimators and distributed inference, a new distributed version of trimmed Hill estimator for heavy tail index is proposed. Considering the case where the number of observations involved in... Proceeded from trimmed Hill estimators and distributed inference, a new distributed version of trimmed Hill estimator for heavy tail index is proposed. Considering the case where the number of observations involved in each machine can be either the same or different and either fixed or varying to the total sample size, its consistency and asymptotic normality are discussed. Simulation studies are particularized to show the new estimator performs almost in line with the trimmed Hill estimator. 展开更多
关键词 Extreme Value Index Distributed Trimmed hill Estimator
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Identification and evaluation of fault-fracture reservoirs in buried hills of the Lower Paleozoic, Chengdao area, China
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作者 Zhiwei Wang Kai Zhang +1 位作者 Yuhan Cheng Qunhu Wu 《Energy Geoscience》 2023年第3期193-202,共10页
The Bohai Bay Basin is a Meso-Cenozoic rifted basin where the Paleozoic buried hills with great hydrocarbon potentials are well developed. The reservoir space types are complex and diverse due to tectonic activities, ... The Bohai Bay Basin is a Meso-Cenozoic rifted basin where the Paleozoic buried hills with great hydrocarbon potentials are well developed. The reservoir space types are complex and diverse due to tectonic activities, making fracture distribution highly heterogeneous. Reservoir identification and mapping is challenging due to their large burial depth and poor resolution of seismic data. An integration of well-logging, seismic data interpretation and core observation is applied to identify three structural unit types in the study area, that is, fault breccia zone, fault cataclastic zone, and fault massive rock zone. A comprehensive well-logging identification template and a comprehensive discriminant function M for the reservoir are established based on the well-logging response characteristics. A M value greater than 0.12 indicates a fault breccia zone, that between 0.04 and 0.12 marks a fault cataclastic zone, and that in the range from 0.02 to 0.04 represents a fault massive rock zone. A seismic prediction method with multi-parameter fusion is proposed in the study. The large-scale fractures are mapped by coherence-clutter parameters, while small fractures are predicted via waveform indication inversion. The spatial distribution of “fault-fracture reservoirs” is precisely mapped by frequency fusion technology. It is found that the fault breccia zones usually occur close to the fault planes, while the fault cataclastic zones are slightly away from the fault planes. The hydrocarbon abundance of the breccia zones is greater than that of the fault cataclastic and fault massive rock zones. 展开更多
关键词 Buried hill Fault-facture Ieservoir Reservoir logging identication Reservoir sei smnic mapping Lower paleozoic Chengdao area
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梯度增强Cosserat连续体的广义Hill定理 被引量:3
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作者 李锡夔 张俊波 张雪 《计算力学学报》 EI CAS CSCD 北大核心 2011年第6期813-820,832,共9页
基于经典Cauchy连续体的Hill定理,在平均场理论的框架下导出了梯度增强Cosserat连续体细、宏观均匀化方法的广义Hill定理。在梯度增强Cosserat连续体中,不仅宏观样条点上的应变和应力张量,而且它们的梯度均作用于与该样条点相关联的细... 基于经典Cauchy连续体的Hill定理,在平均场理论的框架下导出了梯度增强Cosserat连续体细、宏观均匀化方法的广义Hill定理。在梯度增强Cosserat连续体中,不仅宏观样条点上的应变和应力张量,而且它们的梯度均作用于与该样条点相关联的细观表征元(RVE)。依据此广义Hill定理,对梯度增强Cosserat连续体表征元提出了满足Hill-Mandel能量等价条件和平均场理论的强形式及弱形式边界条件。 展开更多
关键词 hill定理 hill—Mandel条件 梯度增强Cosserat连续体 平均场理论 RVE边界条件
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Surface motion of a semi-elliptical hill for incident plane SH waves 被引量:9
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作者 Jianwen Liang Jia Fu 《Earthquake Science》 CSCD 2011年第5期447-462,共16页
A closed-form analytical solution of surface motion of a semi-elliptical cylindrical hill for incident plane SH waves is presented.Although some previous analytical work had already dealt with hill topography of semi-... A closed-form analytical solution of surface motion of a semi-elliptical cylindrical hill for incident plane SH waves is presented.Although some previous analytical work had already dealt with hill topography of semi-circular and shallow circular,our work aims at calculating surface motion of very prolate hill for high incident frequency,and explaining the special vibrating properties of very prolate hill.Accuracy of the solution is checked by boundary conditions,numerical results for surface motion of oblate and prolate hills are calculated, and some conclusions are obtained. 展开更多
关键词 semi-elliptical hill analytical solution plane SH wave surface motion oblate hill prolate hill Mathieu function high frequency
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极值理论中阈值选取的Hill估计方法改进 被引量:14
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作者 宋加山 李勇 +2 位作者 彭诚 王彪 方兆本 《中国科学技术大学学报》 CAS CSCD 北大核心 2008年第9期1104-1108,共5页
利用变点统计理论对极值理论中阈值选择的传统Hill估计方法进行了改进,实现了阈值的定量精确选取,从而减少了因主观判断所引起的阈值选取偏差.将此方法应用到基于极值理论的商业银行操作风险度量中,取得了较好的效果.
关键词 hill估计 变点 阈值
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镉胁迫对续断菊Sonchus asper L.Hill.根系分泌物的影响 被引量:12
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作者 秦丽 李元 +3 位作者 祖艳群 何永美 王吉秀 陈建军 《生态环境学报》 CSCD 北大核心 2012年第3期540-544,共5页
通过盆栽试验,研究了不同Cd质量分数(0、50、100、200 mg.kg-1)对续断菊Sonchus asper L.Hill.根系分泌总有机酸、游离氨基酸、可溶性糖的影响,旨在探明根系分泌物对续断菊超积累Cd的影响。结果表明:Cd胁迫下续断菊根系分泌总有机酸、... 通过盆栽试验,研究了不同Cd质量分数(0、50、100、200 mg.kg-1)对续断菊Sonchus asper L.Hill.根系分泌总有机酸、游离氨基酸、可溶性糖的影响,旨在探明根系分泌物对续断菊超积累Cd的影响。结果表明:Cd胁迫下续断菊根系分泌总有机酸、游离氨基酸和可溶性糖的质量浓度显著增加,同时,总有机酸、可溶性糖和游离氨基酸又促进了植株对Cd的吸收。随着Cd处理质量分数的增加,续断菊地上部和根部镉质量分数显著增加,90 d时续断菊地上部镉质量分数与可溶性糖、游离氨基酸的质量浓度呈极显著正相关,相关系数分别为0.999(P<0.01)和0.995(P<0.01),根部镉质量分数与可溶性糖、游离氨基酸的质量浓度也呈显著正相关,相关系数分别为0.998(P<0.01)和0.987(P<0.05);Cd对续断菊根系可溶性糖的分泌、游离氨基酸的合成有刺激作用,根系分泌的可溶性糖和游离氨基酸可能在续断菊累积镉的过程中有重要作用。 展开更多
关键词 CD 续断菊Sonchus asper L.hill. 根系分泌物 可溶性糖 游离氨基酸
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钾营养对水稻光合速率(Pn)、Hill反应及SOD活力日变化的影响 被引量:33
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作者 蒋德安 翁晓燕 +2 位作者 陆庆 谢学民 饶立华 《植物生理学报(0257-4829)》 CSCD 1996年第1期87-93,共7页
晴天,田间水稻顶部完全展开叶最大的Pn出现在上午8时半左右。低钾营养加剧了“午睡”。8:30~14:30高光强期间Pn与气孔导度和Ci分别呈显著直线正相关。Hill反应活力午后最低,但该时低钾水稻的Hill反应活力较... 晴天,田间水稻顶部完全展开叶最大的Pn出现在上午8时半左右。低钾营养加剧了“午睡”。8:30~14:30高光强期间Pn与气孔导度和Ci分别呈显著直线正相关。Hill反应活力午后最低,但该时低钾水稻的Hill反应活力较钾充足水稻高。SOD活力早晨最低,中午该酶活力增加程度在低钾水稻中更为明显。上述各项均存在着品种间的差异。因此,低钾下水稻“午睡”的加剧由低气孔导度所致,较长时间的低Ci会诱发低的Hill反应活力。 展开更多
关键词 水稻 钾营养 hill反应 光合速率 超氧化物歧化酶
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DD3单晶的Hill屈服准则应用研究 被引量:4
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作者 赵萍 何清华 +2 位作者 李维 陆波 丁智平 《航空材料学报》 EI CAS CSCD 北大核心 2010年第3期70-73,共4页
将Hill屈服准则用于DD3单晶不同温度不同取向的屈服应力预测,结果表明:Hill屈服准则中材料参数的选择对计算结果有很大的影响,且不能同时准确预测单晶三个主要承载方向的屈服强度。根据单晶材料的屈服特点,考虑到单晶材料在任意方向上... 将Hill屈服准则用于DD3单晶不同温度不同取向的屈服应力预测,结果表明:Hill屈服准则中材料参数的选择对计算结果有很大的影响,且不能同时准确预测单晶三个主要承载方向的屈服强度。根据单晶材料的屈服特点,考虑到单晶材料在任意方向上剪应力及其相互作用对屈服强度的影响,通过在Hill屈服函数中加入一修正项建立了适用于单晶的新屈服函数,能对晶体取向为[001],[011]和[111]的屈服强度进行非常准确的预测,在其它方向上结果也比较满意。 展开更多
关键词 DD3单晶 修正hill屈服准则 材料参数 屈服强度
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考虑轧件弹性变形的Hill轧制力显式公式 被引量:9
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作者 吕程 矫志杰 +1 位作者 刘相华 王国栋 《钢铁研究》 CAS 2000年第3期32-33,46,共3页
带钢的轧制力计算和轧辊的压扁计算互为条件 ,针对考虑轧件弹性变形的Hill轧制力公式和Hitchcock轧辊压扁公式 ,推导了它们的显式计算公式 ,从而避免了传统的迭代计算。
关键词 轧制力 压扁 hill公式 显式公式 轧件弹性变形
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