检索结果-南通市图书馆

Computer Modeling in Engineering & Sciences 2023年第2期134卷 1263-1281页

作者： Qi zhou Jinghua Li Ruipu Dong qinghua zhou Boxin Yang College of Shipbuilding Engineering Harbin Engineering UniversityHarbin150001China ShanghaiWaigaoqiao Shipbuilding Co. Ltd.Shanghai200000China College of Mechanical and Electrical Engineering Harbin Engineering UniversityHarbin150001China

Offshore engineering construction projects are large and complex,having the characteristics of multiple execution modes andmultiple resource *** complex internal scheduling processes can be regarded as resourceconstrained project scheduling problems(RCPSPs).To solve RCPSP problems in offshore engineering construction more rapidly,a hybrid genetic algorithmwas *** solve the defects of genetic algorithms,which easily fall into the local optimal solution,a local search operation was added to a genetic algorithm to defend the offspring after crossover/***,an elitist strategy and adaptive operators were adopted to protect the generated optimal solutions,reduce the computation time and avoid premature convergence.A calibrated function method was used to cater to the roulette rules,and appropriate rules for encoding,decoding and crossover/mutation were ***,a simple network was designed and validated using the case study of a real offshore *** performance of the genetic algorithmand a simulated annealing algorithmwas compared to validate the feasibility and effectiveness of the approach.

关键词： Offshore project multi-execution modes resource-constrained project scheduling hybrid genetic algorithm

Hydrogen isotope composition of natural gases from the Tarim Basin and its indication of depositional environments of the source rocks

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China Earth Sciences 2008年第2期51卷 300-311页

作者： LIU QuanYou DAI JinXing LI Jian zhou qinghua Research Institute of Petroleum Exploration and Development PetroChinaBeijing 100083China Langfang Branch of Research Institute of Petroleum Exploration and Development PetroChinaLangfang 065007China

By measuring carbon and hydrogen isotope compositions for C1, C2 and C3 of 74 gas samples, natural gases from the Tarim Basin can be divided into six groups on the basis of their origins: (1) coal-type gas derived from coal measures; (2) coal-type gas generated from the T-J lacustrine mudstones; (3) oil-type gas derived from the Cambrian and low Ordovician marine source rocks; (4) oil-type gas from the source rocks deposited in the marine-transitional facies; (5) mixing gas between gas derived from the Carboniferous transitional source rocks and the Mesozoic humic gas, and (6) mixing gases of thermal genetic gas and little deep gas in the Southwest depression of the Tarim Basin. The δ D values of methane in natural gases originating from different type kerogens are affected by both palaeo-environments of the source rock formation (kerogen types) and thermal maturity, with sedimentary environment (kerogen type) as the main controlling factor. Under the similar thermal maturity, the hydrogen isotope composition of methane is more enriched in deuterium in marine environments than lacustrine one. With the increase of thermal maturity and the increase of carbon atomic numbers of gaseous alkanes, the hydrogen isotopes become enriched in deuterium. The δ D values of ethane and propane (δ D2, δ D3) are controlled mainly by thermal maturity and to a lesser degree by sedimentary environment of the source rock formation. The partial reversal of hydrogen isotopes for gaseous alkanes would be related to the microbial oxidation, mixing of sapropelic and humic gases and / or mixing of gases from similar kerogen sources with various thermal maturities. In the oil-type gas, the sulfate reduction reaction would result in the reversed order of δ D1 and δ D2 (e.g. δ D1>δ D2).

关键词： Tarim Basin hydrogen isotope sedimentary environment thermal maturity

Research on Welding Quality Traceability Model of Offshore Platform Block Construction Process

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2023年第1期134卷 699-730页

作者： Jinghua Li Wenhao Yin Boxin Yang qinghua zhou College of Mechanical and Electrical Engineering Harbin Engineering UniversityHarbin150001China College of Shipbuilding Engineering Harbin Engineering UniversityHarbin150001China

Quality traceability plays an essential role in assembling and welding offshore platform *** improvement of the welding quality traceability system is conducive to improving the durability of the offshore platform and the process level of the offshore ***,qualitymanagement remains in the era of primary information,and there is a lack of effective tracking and recording of welding quality *** welding defects are encountered,it is difficult to rapidly and accurately determine the root cause of the problem from various complexities and scattered quality *** this paper,a composite welding quality traceability model for offshore platform block construction process is proposed,it contains the quality early-warning method based on long short-term memory and quality data backtracking query optimization *** fulfilling the training of the early-warning model and the implementation of the query optimization algorithm,the quality traceability model has the ability to assist enterprises in realizing the rapid identification and positioning of quality ***,the model and the quality traceability algorithm are checked by cases in actual working *** analyses suggest that the proposed early-warningmodel for welding quality and the algorithmfor optimizing backtracking requests are effective and can be applied to the actual construction process.

关键词： Quality traceability model block construction process welding quality management long short-term memory quality data backtracking query optimization algorithm

THE RELATIVE INDEPENDENCE OF SOCIAL AND PUBLIC INTERESTS

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Law in China-Selected Publications from Chinese Universities 2012年第3期7卷 492-511页

作者： Xianfen Feng qinghua zhou School of Law Xi'an Jiaotong UniversityXi'anChina School of Foreign Studies Xi'an Jiaotong UniversityXi'anChina

The social and public interest remains one of the fundamental principles and goals pursued by all legal departments. Its independence is prerequisite to its legal protection. However, the attention given to it by the jurisprudential circle is not enough. Through demonstrations and theoretical exploration, this article conducts an analysis of the independence of the social and public interests, in the hope that it can raise the attention of jurisprudential field,＂ and proposes that the social and public interest, with its independent legal appeal, is an interest pattern which exists in parallel with the personal interest or the national interest because of the independence of society.

关键词：

Improved landscape sampling method for landscape character assessment

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Architectural Research 2023年第1期12卷 118-128页

作者： Xiaodan Yang qinghua zhou Darui Tian School of Architecture Xi’an University of Architecture and TechnologyXi’an 710055China Xi’an Jianda Institute of Urban Planning and Design Xi’an 710055China State Key Laboratory of Green Building in Western China Xi’an 710055China

Landscape character assessment(LCA)is an effective tool for understanding people’s perceptions and preferences of landscape *** than the assessment indicators and subjects,the reliability of photos as assessment objects is equally important for the LCA ***,the commonly used onsite photos are mainly obtained at randomly selected locations by the *** can neither know whether those photos represent the researchers’own preferences,nor,to our best knowledge,can their reliability be tested *** method is also difficult to apply in large-scale geographical *** address these issues,we(1)propose an improved method including the protocols of photography and the sampling of photography locations,in which the fractal principle and stratified random sampling method were combined to minimize the effects of the researchers’preferences and other factors;(2)apply the method to the Guanzhong region as an example,and obtain sampling photos and their geographical coordinates,which can be used as a data package for LCA;(3)use Fractalyse to test the sampled result and receive good *** conclusion,this study extends the methodological chain of the LCA and supports the application of LCA in large-scale regions.

关键词： LCA Photography location sampling Fractals Stratified random sampling Guanzhong region in Shaanxi

Upward propagation of lightning-generated whistler waves into the radiation belts

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2020年第2期63卷 243-248页

作者： GUO MingYue zhou qinghua XIAO FuLiang LIU Si HE YiHua YANG Chang School of Physics and Electronic Sciences Changsha University of Science and TechnologyChangsha 410114China

Lightning-generated whistler(LGW) waves which induce energetic electron precipitation provide an important coupling between the ionosphere and radiation belts. Using the ray-tracing technique, we examine the propagation behaviour of LGW waves and show that they can travel upward into the radiation belts during higher geomagnetic activities due to the plasmapause inward compression, particularly in cases of lower wave frequencies, lower wave normal angles and azimuthal angles. Both perpendicular and parallel group velocities of LGW waves remain in relatively small values inside the plasmasphere but change rapidly to high values outside the plasmasphere. The launching latitude increases with increasing LGW wave normal angle. These results here further reveal a detailed picture on how LGW waves escape out of the plasmasphere and onto the radiation belts.

关键词： lightning-generated whistler waves radiation belts numerical simulation

Magnetospheric chorus wave instability induced by relativistic Kappa-type distributions

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2016年第11期59卷 1739-1745页

作者： YANG QiWu YANG Chang HE YiHua LIU Si zhou qinghua XIAO FuLiang School of Physics and Electronic Sciences Changsha University of Science and Technology

We study the field-aligned propagating magnetospheric chorus wave instability using a fully relativistic wave growth formula,the previously developed relativistic Kappa-type(KT) distribution and the regular Kappa distribution of energetic *** demonstrate that the peak growth rate using the nonrelativistic Kappa simulation is higher than that using either the relativistic KT or the Kappa simulation at/above 100 keV, because the significant relativistic effect yields a reduction in the relativistic anisotropy. The relativistic anisotropy Arel basically decreases as the thermal parameter θ2 increases, allowing the peak growth by relativistic KT or Kappa distribution to stay at the lower frequency region. The growth rates tend to increase with the loss-cone parameter l because the overall anisotropy increases. Moreover, at high energy ~1.0 MeV, both the growth rate and the upper cutoff frequency become smaller as l increases for the relativistic KT calculation because the significant relativistic effect reduces both the resonant anisotropy and the number of the hot electrons, which is in contrast to the relativistic and nonrelativistic Kappa distribution calculations because the less relativistic or non-relativistic effect enhances the resonant anisotropy as l increases. The above results can be applied to the whistler-mode wave instability in the outer radiation belts of the Earth, the Jovian inner magnetosphere and other astrophysical plasmas where relativistic electrons often exist.

关键词： Kappa-type distribution energetic electrons wave-particle interaction chorus wave instability

Effect of thermal shield and gas flow on thermal elastic stresses in 300mm silicon crystal

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2006年第z2期25卷 45-50页

作者： GAO Yu XIAO qinghua zhou Qigang DAI Xiaolin TU Hailing General Research Institute for Nonferrous Metals Beijing 100088 China General Research Institute for Nonferrous Metals Beijing 100088 China General Research Institute for Nonferrous Metals Beijing 100088 China General Research Institute for Nonferrous Metals Beijing 100088 China General Research Institute for Nonferrous Metals Beijing 100088 China

The thermal elastic stresses induced in 300 mm Si crystal may be great troubles because it can incur the generation of dislocations and undesirable excessive residual stresses. A special thermal modeling tool, CrysVUn, was used for numerical analysis of thermal elastic stresses and stress distribution of 300 mm Si crystal under the consideration of different thermal shields and gas flow conditions. The adopted governing partial equations for stress calculation are Cauchy′s first and second laws of motion. It is demonstrated that the presence and shape of thermal shield, the gas pressure and velocity can strongly affect von Mises stress distribution in Si crystal. With steep-wall shield, however, the maximal stress and ratio of high stress area are relatively low. With slope-wall shield or without shield, both maximal stress and ratio of high stress area are increased in evidence. Whether thermal shields are used or not, the increase of gas flow velocity could raise the stress level. In contrast, the increase of gas pressure cannot result in so significant effect. The influence of thermal shield and gas flow should be attributed to the modification of heat conduction and heat radiation by them.

关键词： thermal elastic stress simulation 300 mm Si single crystal

Butterfly distribution of Earth＇s radiation belt relativistic electrons induced by dayside chorus

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2018年第2期61卷 212-218页

作者： jin yuyue yang chang he yihua liu si zhou qinghua xiao fuliang school of physics and electronic sciences changsha university of science and technologyChangsha 410004China

Previous theoretical studies have shown that dayside chorus can produce butterfly distribution of energetic electrons in the Earth＇s radiation belts by preferentially accelerating medium pitch angle electrons, but this requires the further confirmation from high- resolution satellite observation. Here, we report correlated Van Allen Probes data on wave and particle during the 1 I-13 April, 2014 geomagnetic storm. We find that a butterfly pitch angle distribution of relativistic electrons is formed around the location L = 4.52, corresponding to the presence of enhanced dayside chorus. Using a Gaussian distribution fit to the observed chorus spectra, we calculate the bounce-averaged diffusion rates and solve two-dimensional Fokker-Planck equation. Numerical results demonstrate that acceleration by dayside chorus can yield the electron flux evolution both in the energy and butterfly pitch angle distribution comparable to the observation, providing a further evidence for the formation of butterfly distribution of relativistic electrons driven by very low frequency （VLF） plasma waves.

关键词： butterfly distribution relativistic electrons radiation belts wave-particle interaction dayside chorus

A Note on the Property of ψ-Function

在线全文

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural Sciences 2011年第2期16卷 139-142页

作者： XIE Zitian zhou qinghua Department of Mathematics Zhaoqing University Zhaoqing526061 Guangdong China

About the accurate value of ψ （ x ） = Γ′ （ x ） / Γ （ x）, we know only ψ （1）and ψ （1/ 2）.In this paper, by calculating the accurate values of some series expansion of a function and applying some skills of complex analysis, we prove that the expression of the ψ-function admits a finite expression in elementary function for rational number z. As an application, some examples are given.

关键词： ψ-function Γ-function Euler’s constant