检索结果-南通市图书馆

Multiple air route crossing waypoints optimization via artificial potential field method

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2021年第4期34卷 279-292页

作者： Bizhao PANG wei dai Xinting HU Fuqing dai Kin Huat LOW School of Mechanical and Aerospace Engineering Nanyang Technological UniversitySingapore 639798Singapore Air Traffic Management Research Institute Nanyang Technological UniversitySingapore 637460Singapore School of Air Traffic Management Civil Aviation University of ChinaTianjin 300300China

Air route crossing waypoint optimization is one of the effective ways to improve airspace utilization,capacity and resilience in dealing with air traffic congestion and ***,research is lacking on the optimization of multiple Crossing Waypoints(CWPs)in the fragmented airspace separated by Prohibited,Restricted and Dangerous areas(PRDs).To tackle this issue,this paper proposes an Artificial Potential Field(APF)model considering attractive forces produced by the optimal routes and repulsive forces generated by *** optimization framework based on the APF model is proposed to optimize the different airspace topologies varying the number of CWPs,air route segments and *** on the framework,an adaptive method is developed to dynamically control the optimization process in minimizing the total air route *** proposed model is applied to a busy controlled *** the obtained results show that after optimization the safety-related indicators:conflict number and controller workload reduced by 7.75%and 6.51%*** for the cost-effectiveness indicators:total route length,total air route cost and non-linear coefficient,declined by 1.74%,3.13%and 1.70%*** the predictability indicator,total flight delay,saw a notable reduction by 7.96%.The proposed framework and methodology can also provide an insight in the understanding of the optimization to other network systems.

关键词： Adaptive method Air route network Air traffic control Potential field Structure optimization

Non-steroidal anti-inflammatory drugs in prevention of gastric cancer

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2006年第18期12卷 2884-2889页

作者： Yun dai wei-Hong Wang Department of Gastroenterology First Hospital Peking University Beijing 100034 China

Non-steroidal anti-inflammatory drugs （NSAIDs） including cydooxygenase 2 （COX-2） selective inhibitors, are potential agents for the chemoprevention of gastric cancer. Epidemiological and experimental studies have shown that NSAID use is associated with a reduced risk of gastric cancer although many questions remain unanswered such as the optimal dose and duration of treatment. The possible mechanisms for the suppressor effect of NSAIDs on carcinogenesis are the ability to induce apoptosis in epithelial cells and regulation of angiogenesis. Both COX-dependent and COX- independent pathways have a role in the biological activity of NSAIDs. Knowledge of how NSAIDs prevent neoplastic growth will greatly aid the design of better chemopreventive drugs and novel treatments for gastric cancer.

关键词： Nonsteroidal anti-inflammatory drugs Gastric cancer Cyclooxygenase Prevention Intervention

L^(2) Boundedness of the Fourier Integral Operator with Inhomogeneous Phase Functions

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

Acta Mathematica Sinica,English Series 2023年第8期39卷 1525-1546页

作者： Jia wei dai Jie Cheng CHEN School of Electronic and Information Engineering(School of Big Data Science) Taizhou UniversityTaizhou 318000P.R.China Department of Mathematics Zhejiang Normal UniversityJinhua 321004P.R.China

In this paper,we investigate the L^(2) boundedness of the Fourier integral operator Tφ,a with smooth and rough symbols and phase functions which satisfy certain non-degeneracy *** particular,if the symbol a∈L∞Smρ,the phase functionφsatisfies some measure conditions and ∇kξφ(·,ξ)L∞≤C|ξ|−k for all k≥2,ξ≠0,and some∈>0,we obtain that Tφ,a is bounded on L^(2) if m

关键词： Fourier integral operator,L^(2)boundedness inhomogeneous phase

同方期刊数据库

Acoustic characteristics of bi-directional turbines for thermoacoustic generators

在线全文

学校读者我要写书评

暂无评论

Frontiers in Energy 2022年第6期16卷 1027-1036页

作者： Dongdong LIU Yanyan CHEN wei dai Ercang LUO University of Chinese Academy of Sciences Beijing 101408China Technical Institute of Physics and Chemistry Chinese Academy of SciencesBeijing 100190China

Bi-directional turbines combined with rotary motors may be a feasible option for developing high power thermoacoustic generators with low cost.A general expression for the acoustic characteristics of the bidirectional turbine was proposed based on theoretical derivation,which was validated by computational fluid dynamics modeling of an impulse turbine with fixed guide *** structure of the turbine was optimized primarily using steady flow with an efficiency of near 70%(the shaft power divided by the total energy consumed by the turbine).The turbine in the oscillating flow was treated in a lumped-parameter model to extract the acoustic impedance characteristics from the simulation *** key acoustic impedance characteristic of the turbine was the resistance and inertance due to complex flow condition in the turbine,whereas the capacitance was treated as an adiabatic case because of the large-scale flow channel relative to the heat penetration *** for the impedance were obtained from both theoretical predictions and numerical *** good fit of the correlations shows that these characteristics are valid for describing the bi-directional turbine,providing the basis for optimization of the coupling between the thermoacoustic engine and the turbine using quasi-one-dimensional theory in the frequency domain.

关键词： thermoacoustic power generator acoustic characteristics bi-directional impulse turbine energy conversion

Carcinoma of Colon: A Rare Cause of Fever of Unknown Origin

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Cancer Research 2012年第2期24卷 157-160页

作者： wei dai Kyu-sung Chung Department of Gastroenterology the First Affiliated Hospital of Kunming Medical CollegeKunming 650032China Department of Gastroenterology the Affiliated YanAn Hospital of Kunming Medical CollegeKunming 650051China

Fever of unknown origin （FUO） was originally defined as a body temperature greater than 38.3℃ on several occasions longer than 3 weeks, with a diagnosis that remains unclear after 7 days of obligatory investigation. Only a few types of solid tumors have been associated with FUO. We described 2 patients who had recurrent fever but no other specific gastrointestinal symptoms where carcinoma of the colon was the only identifiable cause. In the first case, a mass arising from the sigmoid colon was found without any nodal metastasis, and the fever was resolved after three days of the surgical resection. In the second case, advanced adenocarcinoma was found in the ascending colon together with liver cirrhosis. Although it was not possible to surgically remove this tumor, prolonged fever in the patient was most likely due to the carcinoma. These cases indicate that clinicians should consider carcinoma of the colon in the differential diagnosis of patients with FUO.

关键词： Colon Carcinoma Fever FUO

Characteristics of soil organic carbon mineralization and influence factor analysis of natural Larix olgensis forest at different ages

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2019年第4期30卷 1495-1506页

作者： Ling Liu Haiyan Wang wei dai College of Soil and Water Conservation Beijing Forestry UniversityBeijing 100083People's Republic of China Key Lab of Soil and Water Conservation and Desertification Combating Ministry of EducationBeijing Forestry UniversityBeijing 100083People's Republic of China College of Forestry Beijing Forestry UniversityBeijing 100083People's Republic of China

Soil organic carbon(SOC)mineralization is closely related to carbon source or sink of terrestrial *** stands of Larix olgensis on the Jincang forest farm,Jilin Province were selected to investigate the dynamics of SOC mineralization and its correlations with other soil properties in a young forest and mid-aged forest at soil depths of 0–10,>10–20,>20–40 and>40–60 *** results showed that compared with a mid-aged forest,the SOC stock in the young forest was 32%*** mineralizable soil carbon(C0)in the young forest was 1.1–2.5 g kg^-1,accounting for 5.5–8.1%of total SOC during the 105 days incubation period and 0.3–1.5 g kg^-1 in the mid-aged forest at different soil depths,occupying 2.8–3.4%of total *** was a significant difference in C0 among the soil *** dynamics of the SOC mineralization was a good fit to a three-pool(labile,intermediate and stable)carbon decomposition kinetic *** SOC decomposition rate for different stand ages and different soil depths reached high levels for the first 15 *** analysis revealed that the C0 was significantly positively related with SOC content,soil total N(TN)and readily available K(AK)*** labile soil carbon pool was significantly related to SOC and TN concentration,and significantly negatively correlated with soil bulk *** intermediate carbon pool was positively associated with TN and *** stable carbon pool had negative correlations with SOC,TN and AK.

关键词： Larix olgensis Soil organic carbon mineralization Soil physical and chemical properties Carbon pools Forest age

Factors affecting soil organic carbon in a Phyllostachys edulis forest

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2019年第4期30卷 1487-1494页

作者： Xiaoxiao Liu Yaning Luan wei dai Bing Wang Aona dai College of Forestry Beijing Forestry UniversityQinghua East Road No.35Haidian DistrictBeijing 100083China Research Institute of Forest Ecology Environment and ProtectionChinese Academy of ForestryBeijing Summer Palace and the Red FlagHaidian DistrictBeijing 100091China

Phyllostachys edulis plays an important role in maintaining carbon *** examined the effects of soil properties on organic carbon content in a *** forest on Dagang Mountain,Jiangxi Province,*** on correlation and stepwise multiple regression analyses,the effects of seven soil factors on organic carbon and their sensitivities to change were studied using path and sensitivity *** results revealed differences in the interconnections and intensities of soil factors on organic *** porosity,field capacity,and ammonium nitrogen levels were the main factors affecting organic carbon in the *** porosity had a strong direct effect on organic carbon content and a strong indirect effect through field *** capacity and ammonium nitrogen levels mainly affected organic carbon *** capacity,soil porosity,and ammonium nitrogen content,as well as bulk density,b-glucosidase activity,and invertase activity,were sensitive *** oxidase activity was *** study provides a theoretical basis for understanding the effects of soil factors on organic carbon,which can be utilised to improve *** forest management strategies and promote carbon sequestration capacities.

关键词： Phyllostachys edulis Soil organic carbon Impact factor Path analysis Sensitivity analysis

An Integrated Incentive Framework for Mobile Crowdsourced Sensing

在线全文

学校读者我要写书评

暂无评论

Tsinghua Science and Technology 2016年第2期21卷 146-156页

作者： wei dai Yufeng Wang Qun Jin Jianhua Ma College of Telecommunications and Information Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003China. Department of Human Informatics and Cognitive Sciences Waseda UniversitySaitama 359-1192Japan. Faculty of Computer&Information Sciences Hosei UniversityTokyo 184-8584Japan

Currently, mobile devices （e.g., smartphones） are equipped with multiple wireless interfaces and rich builtin functional sensors that possess powerful computation and communication capabilities, and enable numerous Mobile Crowdsourced Sensing （MCS） applications. Generally, an MCS system is composed of three components： a publisher of sensing tasks, crowd participants who complete the crowdsourced tasks for some kinds of rewards, and the crowdsourcing platform that facilitates the interaction between publishers and crowd participants. Incentives are a fundamental issue in MCS. This paper proposes an integrated incentive framework for MCS, which appropriately utilizes three widely used incentive methods： reverse auction, gamification, and reputation updating. Firstly, a reverse-auction-based two-round participant selection mechanism is proposed to incentivize crowds to actively participate and provide high-quality sensing data. Secondly, in order to avoid untruthful publisher feedback about sensing-data quality, a gamification-based verification mechanism is designed to evaluate the truthfulness of the publisher＇s feedback. Finally, the platform updates the reputation of both participants and publishers based on their corresponding behaviors. This integrated incentive mechanism can motivate participants to provide high-quality sensed contents, stimulate publishers to give truthful feedback, and make the platform profitable.

关键词： mobile crowdsourced sensing incentive mechanism reverse auction gamification reputation updating

Drag-reduction of 3D printed shark-skin-like surfaces

在线全文

学校读者我要写书评

暂无评论

Friction 2019年第6期7卷 603-612页

作者： wei dai Masfer ALKAHTANI Philip RHEMMER Hong LIANG Department of Mechanical Engineering Texas A&M UniversityCollege StationTX 77843USA Institute for Quantum Science and Engineering(IQSE) Texas A&M UniversityCollege StationTX 77843USA Center for Quantum Optics and Quantum Informatics KACSTRiyadh 11442Saudi Arabia Department of Electrical and Computer Engineering Texas A&M UniversityCollege StationTX 77843USA

The marvels of the slippery and clean sharkskin have inspired the development of many clinical and engineering products, although the mechanisms of interfacial interaction between the sharkskin and water have yet to be fully understood. In the present research, a methodology was developed to evaluate morphological parameters and to enable studying the effects of scale orientation on the fluidic behavior of water. The scale orientation of a shark skin was defined as the angle between the ridges and fluid flow direction. Textured surfaces with a series orientation of scales were designed and fabricated using 3 D printing of acrylonitrile butadiene styrene(ABS). The fluid drag performance was evaluated using a rheometer. Results showed that the shark–skin-like surface with 90 degree orientation of scales exhibited the lowest viscosity drag. Its maximum viscosity reduction was 9%. A viscosity map was constructed based on the principals of fluid dynamic. It revealed that the drag reduction effect of a shark-skin-like surface was attributed to the low velocity gradient. This was further proven using diamond nitrogen-vacancy sensing where florescent diamond particles were distributed evenly when the velocity gradient was at the lowest. This understanding could be used as guidance for future surface design.

关键词： shark skin 3D printing textured surface drag reduction nitrogen vacancy