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Dynamics of high-speed train in crosswinds based on an air-train-track interaction model
Wanming Zhai,Jizhong Yang,Zhen Li,Haiyan Han 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.20 No.2
A numerical model for analyzing airtraintrack interaction is proposed to investigate thedynamic behavior of a high-speed train running on a track in crosswinds. The model is composed of atraintrack interaction model and a trainair interaction model. The traintrack interaction model is built onthe basis of the vehicletrack coupled dynamics theory. The trainair interaction model is developed basedon the train aerodynamics, in which the Arbitrary LagrangianEulerian (ALE) method is employed to dealwith the dynamic boundary between the train and the air. Based on the airtraintrack model, characteristicsof flow structure around a high-speed train are described and the dynamic behavior of the high-speed trainrunning on track in crosswinds is investigated. Results show that the dynamic indices of the head car arelarger than those of other cars in crosswinds. From the viewpoint of dynamic safety evaluation, the runningsafety of the train in crosswinds is basically controlled by the head car. Compared with the generally usedassessment indices of running safety such as the derailment coefficient and the wheel-load reduction ratio,the overturning coefficient will overestimate the running safety of a train on a track under crosswindcondition. It is suggested to use the wheel-load reduction ratio and the lateral wheelrail force as thedominant safety assessment indices when high-speed trains run in crosswinds.
MicroRNA-5582-3p alleviates the progression of osteosarcoma via targeting FZD4
Qu Wanming,Zhou Hongbin 대한독성 유전단백체 학회 2023 Molecular & cellular toxicology Vol.19 No.2
Background Dysfunction of microRNAs (miRNAs) is a common characteristic during cancer progression. The suppressive function of miR-5582-3p in cancers has been emerged in recent studies, however, the clinical value and novel targets of miR-5582-3p in osteosarcoma (OS) have not been identifi ed. Objective Investigate the function and underlying mechanism of miR-5582-3p in OS. Results miR-5582-3p expression was signifi cantly reduced in OS tissues and cells. Lower level of miR-5582-3p had closed relationship with the advanced development and poor 5-year overall survival of OS patients. Transfection of miR-5582-3p in OS cells obviously inhibited the cell proliferation, invasion and colony formation. Highly expressed miR-5582-3p also delayed the cell cycle progression and promoted cell apoptosis. Furthermore, FZD4 was validated as a target of miR-5582-3p. miR- 5582-3p interacted with the 3′-untranslated regions (3′-UTR) of FZD4 and reduced FZD4 expression in OS cells. Expression of miR-5582-3p was inversely correlated with that of FZD4 in OS tissues. Transfection of FZD4 rescued the suppressed OS cell proliferation, attenuated miR-5582-3p induced cell apoptosis and invasion. Conclusions Our fi ndings uncovered the novel anti-cancer potency of miR-5582-3p in OS via repressing FZD4, suggesting the possibility of miR-5582-3p as a therapeutic target of OS.
Dynamics of high-speed train in crosswinds based on an air-train-track interaction model
Zhai, Wanming,Yang, Jizhong,Li, Zhen,Han, Haiyan Techno-Press 2015 Wind and Structures, An International Journal (WAS Vol.20 No.2
A numerical model for analyzing air-train-track interaction is proposed to investigate the dynamic behavior of a high-speed train running on a track in crosswinds. The model is composed of a train-track interaction model and a train-air interaction model. The train-track interaction model is built on the basis of the vehicle-track coupled dynamics theory. The train-air interaction model is developed based on the train aerodynamics, in which the Arbitrary Lagrangian-Eulerian (ALE) method is employed to deal with the dynamic boundary between the train and the air. Based on the air-train-track model, characteristics of flow structure around a high-speed train are described and the dynamic behavior of the high-speed train running on track in crosswinds is investigated. Results show that the dynamic indices of the head car are larger than those of other cars in crosswinds. From the viewpoint of dynamic safety evaluation, the running safety of the train in crosswinds is basically controlled by the head car. Compared with the generally used assessment indices of running safety such as the derailment coefficient and the wheel-load reduction ratio, the overturning coefficient will overestimate the running safety of a train on a track under crosswind condition. It is suggested to use the wheel-load reduction ratio and the lateral wheel-rail force as the dominant safety assessment indices when high-speed trains run in crosswinds.
劉婉明(Liu Wanming) 경북대학교 아시아연구소 2011 아시아연구 Vol.- No.13
日本華僑라는 身分은 馮乃超가 浪漫主義 詩人에서 마르크스주의 革命家로 변모하는 데에 있어서 중요한 의미가 있었다. 家族들의 革命史, 異邦僑民의 “國恥”체험, 어릴 때부터 체험한 民族救濟 엘리트 교육을 받은 경험, 유년 시절 처음으로 고향을 찾았을 때 조국으로부터 異族과 罪人 취급받은 체험 등이 상호 작용하여 풍내초에게는 異邦과 고국에게 동시에 축출당한 기억으로 남았다. 이러한 기억들이 풍내초로 하여금 마르크스주의자로 변모하게 하였고, 民族國家를 초탈한 無産階級革命家로 변모하는 데에 있어서 중요한 역할을 하였다. 1911年, 革命黨이 홍콩에 있던 保皇黨의 機關報인 『商報』館을 습격한 사건은 풍내초로 하여금 민족국가 공동체 의식에 대한 의구심을 갖게 했으며, 그가 민족국가 신분에 대해 위기감을 느끼게 된 계기가 되었다. 1928년 귀국을 결정하고 無産階級 文學運動 先鋒 엘리트 모습으로, 민족 救援者익 모습을 다시 드러낸 풍내초는 소설 「故鄕」에서 자신의 『商報』館 습격 사건에 대한 체험을 다루었다. 그 목적은 마르크스주의 언어로서 고향에서 축출당한 “나”가 어떻게 최종적으로 無産階級大衆 속에서 새로운 歸屬을 찾았는지에 대한 寓言이었다. 이 우언의 결론에서 그는 개개인의 구원은 階級革命을 통해 실현되어야 하며, “나”는 민족국가에 소속되었던 데로부터 무산대중에 귀속되었다고 하였다. 『商報』館 사건을 다시 다루는 것에서 우리는 풍내초가 唯物史觀이 허용하는 역사 구원을 희망하였으며, 마르크스주익 언어로 묘사해낸 역사 진행 속에서 가장 진보적이고 민족국가의 한계를 초탈한 무산계급을 통해 오랫동안 그를 괴롭혔던 민족국가의 신분 문제를 해결하고자 하였음을 알 수 있다. Being an overseas Chinese in Japan had a great effect on Feng Naichao’s transformation from a romantic poet to a Marxist. The family history of the Fengs’ participation in revolution, the racial discrimination suffered in Japan, the elite education for raising the future savior of the Chinese nation, the memories of been treated like a pagan and a guilty person in his motherland during his first hometown journey, all of these experiences interacted with each other during Feng’s life. As a result, the memories of been exiled by both his motherland and Japan led to Feng Naichao’s national identity crisis which, later on, became the psychological reason for his transformation to a Marxist and his participation in the proletarian revolution which called for the transcending of all nation-states. When some of Sun Yat-sen’s radical supporters attacked the office of Shang Bao, which was the official newspaper of Kang Youwei’s reform party in Hong Kong in 1911, Feng Naichao experienced the whole event. It made him started to question the community conscience of nation-state, and finally became the fuse of his nation-state identity crisis. Feng Naichao decided to back to his motherland again in 1928, in order to advocate the revolutionary literature movement and play the role of the savior again as an elite proletarian revolutionist. At exactly the same time, he wrote his own experience of the Shang Bao event in a novel called The Hometown. By retelling the event in the language of Marxism, Feng turned the whole story into a parable about how the hero who was exiled by his motherland finally found a new community in the proletarian class that he can belong to. At the end of the parable, the salvation of an individual relied on the class revolution. A class identity filled the blank left by the absence of the nation-state identity, and the hero finally enrolled himself in a class instead of a nation-state. Feng’s retelling of the story of the Shang Bao event shows that in order to get rid of his nation-state identity crisis which bothered him for a long time, he chose to count on the salvation promised by historical materialism, and enrolled in the proletarian class which, in a Marxist’s history picture, is announced to be the only class that can transcend all the nation-states.
A mechanical model of vehicle-slab track coupled system with differential subgrade settlement
Yu Guo,Wanming Zhai,Yu Sun 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.66 No.1
Post-construction subgrade settlement especially differential settlement, has become a key issue in construction and operation of non-ballasted track on high-speed railway soil subgrade, which may also affect the dynamic performance of passing trains. To estimate the effect of differential subgrade settlement on the mechanical behaviors of the vehicle-slab track system, a detailed model considering nonlinear subgrade support and initial track state due to track self-weight is developed. Accordingly, analysis aiming at a typical high-speed vehicle coupled with a deteriorated slab track owing to differential subgrade settlement is carried out, in terms of two aspects: (i) determination of an initial mapping relationship between subgrade settlement and track deflections as well as contact state between track and subgrade based on a semi-analytical method; (ii) simulation of dynamic performance of the coupled system by employing a time integration approach. The investigation indicates that subgrade settlement results in additional track irregularity, and locally, the contact between the concrete track and the soil subgrade is prone to failure. Moreover, wheel-rail interaction is significantly exacerbated by the track degradation and abnormal responses occur as a result of the unsupported areas. Distributions of interlaminar contact forces in track system vary dramatically due to the combined effect of track deterioration and dynamic load. These may not only intensify the dynamic responses of the coupled system, but also have impacts on the long-term behavior of the track components.
Effect of noise barrier on aerodynamic performance of high-speed train in crosswind
Hai Zhao,Wanming Zhai,Zaigang Chen 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.20 No.4
A three-dimensional aerodynamic model and a vehicle dynamics model are established toinvestigate the effect of noise barrier on the dynamic performance of a high-speed train running on anembankment in crosswind in this paper. Based on the developed model, flow structures around the train withand without noise barrier are compared. Effect of the noise barrier height on the train dynamic performanceis studied. Then, comparisons between the dynamic performance indexes of the train running on thewindward track and on the leeward track are made. The calculated results show that the noise barrier hassignificant effects on the structure of the flow field around the train in crosswind and thus on the dynamicperformance of the high-speed train. The dynamic performance of the train on the windward track is betterthan that on the leeward track. In addition, various heights of the noise barrier will have different effects onthe train dynamic performance. The dynamic performance indexes keep decreasing with the increase of thenoise barrier height before the height reaches a certain value, while these indexes have an inverse trend whenthe height is above this value. These results suggest that optimization on the noise barrier height is possibleand demonstrate that the designed noise barrier height of the existing China Railway High-speed lineanalysed in this article is reasonable from the view point of the flow field structure and train dynamicperformance although the noise barrier is always designed based on the noise-related standard.
Energy Efficiency Optimization for multiuser OFDM-based Cognitive Heterogeneous networks
( Bing Ning ),( Aihua Zhang ),( Wanming Hao ),( Jianjun Li ),( Shouyi Yang ) 한국인터넷정보학회 2019 KSII Transactions on Internet and Information Syst Vol.13 No.6
Reducing the interference to the licensed mobile users and obtaining the energy efficiency are key issues in cognitive heterogeneous networks. A corresponding rate loss constraint is proposed to be used for the sensing-based spectrum sharing (SBSS) model in cognitive heterogeneous networks in this paper. Resource allocation optimization strategy is designed for the maximum energy efficiency under the proposed interference constraint together with average transmission power constraint. An efficiency algorithm is studied to maximize energy efficiency due to the nonconvex optimal problem. Furthermore, the relationship between the proposed protection criterion and the conventional interference constraint strategy under imperfect sensing condition for the SBSS model is also investigated, and we found that the conventional interference threshold can be regarded as the upper bound of the maximum rate loss that the primary user could tolerate. Simulation results have shown the effectiveness of the proposed protection criterion overcome the conventional interference power constraint.
On the late-time behaviour of a bounded, inviscid two-dimensional flow
Dritschel, David G.,Qi, Wanming,Marston, J. B. Cambridge University Press 2015 Journal of fluid mechanics Vol.783 No.-
<P>Using complementary numerical approaches at high resolution, we study the late-time behaviour of an inviscid incompressible two-dimensional flow on the surface of a sphere. Starting from a random initial vorticity field comprised of a small set of intermediate-wavenumber spherical harmonics, we find that, contrary to the predictions of equilibrium statistical mechanics, the flow does not evolve into a large-scale steady state. Instead, significant unsteadiness persists, characterised by a population of persistent small-scale vortices interacting with a large-scale oscillating quadrupolar vorticity field. Moreover, the vorticity develops a stepped, staircase distribution, consisting of nearly homogeneous regions separated by sharp gradients. The persistence of unsteadiness is explained by a simple point-vortex model characterising the interactions between the four main vortices which emerge.</P>
A Method for Mapping Sensor Data to SSN Ontology
Xiaoming Zhang,Yunping Zhao,Wanming Liu 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.9
Along with the continuous development of the sensor network technology, sensors from all over the world are constantly producing sensor data. However, the sensor data from different source is hard to work together for lack of semantic. Fortunately, SSN ontology provide a way to represent sensor data semantically, but how to transform sensor data into the instance of SSN ontology conveniently is still an issue to be considered. This paper proposed a solution to map sensor data to SSN ontology automatically based on a predefined XML-based document. We design a mapping language SASML (Sensors Annotation and Semantic Mapping Language) which provide a schema to annotate sensors and sources so as to generate a XML document for mapping. Then, an algorithm (namely SDRM) is designed to automatically transform sensor data, which described by SASML, to RDF conforming to SSN ontology, according to the mapping document and the element correspondences between the SASML and SSN ontology. Further, a case study about sensor data from greenhouse is presented to illustrate our method, and a prototype is also developed to demonstrate the feasibility and effectiveness.