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991.
The combined loading tests of 5754O aluminum alloy sheet are used to verify the yield function. Three yield functions are implemented into the commercial finite element model (FEM) code ABAQUS as a user material subroutine UMAT for the FEM simulation of the combined loading tests. The comparison of the simulating and experimental results shows that the modified Yld2000-2d yield function can describe the mechanical behavior of 5754O aluminum alloy sheet under combined loading paths reasonably while other three yield functions do not. The performance of the modified Yld2000-2d yield function on describing the mechanical behavior under combined loading paths is analyzed in detail. It is concluded that the modified Yld2000-2d yield function can be adopted to describe the deformation behavior of 5754O aluminum alloy sheet for industrial applications. 相似文献
992.
This article presents the results of a study exploring travellers’ preferences for middle-distance travel using Q-methodology.
Respondents rank-ordered 42 opinion statements regarding travel choice and motivations for travel in general and for car and
public transport as alternative travel modes. By-person factor analysis revealed four distinct preference segments for middle-distance
travel: (1) choice travellers with a preference for public transport, (2) deliberate-choice travellers, (3) choice travellers
with car as dominant alternative, and (4) car-dependent travellers. These preference segments differ in terms of the levels
of involvement and cognitive effort in travel decision making, the travel consideration-set and underlying motivations. The
study showed that for most people there is more to travel than getting from point A to point B, and that there is considerable
heterogeneity in middle-distance travel preferences. Policy implications for reducing the need for travel and promoting a
modal shift from car to other travel modes are discussed. 相似文献
993.
Construction of eukaryotic recombinant vector of renalase and its expression as a eukaryotic protein
Renalase is a secreted amine oxidase that metabolizes catecholamines. It has been proposed to modulate blood pressure and
heart rate and its downregulation might result in hypertension. Despite its potential relevance for human health, the biochemical
characterization of renalase is still scarce. The aim of this study is to synthesize the human renalase eukaryotic protein
by genetic engineering. The human renalase gene was amplified by polymerase chian reaction (PCR). After digestion by BamH
I and Xho I enzymes, the DNA fragments were cloned into the transfer vector, pFastBacHTb-Fc, to generate the pFastBacHTb-renalase
expression vector. The ligation products were transformed into E. coli DH10Bac to obtain recombinant transposon rBacmid-renalase. The recombinant transposon was further transferred into insect
high-V cells, and the recombinant human renalase eukaryotic protein was expressed successfully. 相似文献
994.
995.
Hydraulic butterfly valves have been widely applied in marine engineering because of their large switching torque, low pressure
loss and suitability for large and medium diameter pipelines. Due to control problems resulting from switching angular speeds
of the hydraulic butterfly valve, a throttle-governing control mode has been widely adopted, and detailed analysis has been
carried out worldwide on the structural principle concerning speed-regulation and the load torque on the shaft while opening
or closing a hydraulic butterfly valve. However relevant reports have yet been published on the change law, the error and
the influencing factors of the rotational angular velocity of the hydraulic butterfly valve while opening and closing. In
this article, research was based on some common specifications of a hydraulic butterfly valve with a symmetrical valve flap
existing in a marine environment. The throttle governing system supplied by the accumulator to achieve the switching of the
hydraulic control valve was adopted, and the mathematical models of the system were established in the actual conditions while
the numerical simulations took place. The simulation results and analysis show that the rotational angular velocity and the
error of the hydraulic butterfly valve while switching is influenced greatly by the drainage amount of the accumulator, resulting
in pressure loss in the pipeline, the temperature of hydraulic medium and the load of the hydraulic butterfly valve. The simulation
results and analysis provide a theoretical basis for the choice of the total capacity of the accumulator and pipeline diameters
in a throttle governing system with a hydraulic butterfly valve. It also determines the type and specification of the hydraulic
butterfly valve and the design of motion parameters of the transported fluid. 相似文献
996.
Xinming Lian Xiaoxiao Li Dexin Zhou Peishi Yan 《Transportation Research Part D: Transport and Environment》2012,17(8):585-587
We compare the avoidance distances from Qinghai–Tibet Highway between two sympatric ungulate species, Tibetan antelope and Tibetan gazelle, in June and August of 2010 and July and August of 2011. The results show that Tibetan antelope avoid the road significantly more than Tibetan gazelle. At the times of day when traffic volume is high the avoidance distance in both species unexpectedly decreases. This suggests they are relatively undisturbed by the traffic but that they have a diurnal rhythm that involves resting far from the road in night. 相似文献
997.
Sloshing phenomenon in the liquid cargo carriers has caught the attention of researchers as the interaction between the sloshing
waves and structure is one of the key point and difficulty in the study of sloshing. In this paper, we captured the free surface
with a volume of fluid (VOF) method and then calculated the motions and responses of the structure by adopting the Reynolds-averaged
Navier-Stokes (RANS) equations for the whole fluid domain. With the use of user defined functions (UDF) in Fluent, the interaction
between fluid and structure was then simulated. As a reasonable simplification, the authors studied the response of a single
cantilever in a tank under sloshing loads; Further study should pay more attention to the mechanisms of interaction between
sloshing waves and elastic structures. 相似文献
998.
For the large-scale application requirements of the belt-type networks, the mathematical modeling as well as quantitative
analysis for the scalability of the network based on average path length is completed in this paper, and the theorem for the
scale scalability of the belt-type networks is derived. The theorem provides a calculation formula for the upper limit of
node scale theory of the belt-type networks and a calculation formula for the upper limit of single node load theory. 相似文献
999.
立足于高速公路智能交通领域规划设计,为行业决策与企业管理者提供针对性的技术咨询服务.通过探索服务的定位、原则、方法,在服务模式上寻求创新,依靠整合项目资源和创建内核力量在服务内容上拓宽思路,通过构建学习型团队,在工作模式上突破求新.为交通信息化的发展提出创新性的见解. 相似文献
1000.