检索结果-南通市图书馆

Journal of Environmental Sciences 2024年第5期139卷 12-22页

作者： yi Yuan Wen-Long wang Zhi-Wei wang jin wang Qian-Yuan Wu Key Laboratory of Microorganism Application and Risk Control of Shenzhen Guangdong Provincial Engineering Research Center for Urban Water Recycling and Environmental SafetyInstitute of Environment and EcologyShenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055China Shenzhen Environmental Science and New Energy Technology Engineering Laboratory Tsinghua-Berkeley Shenzhen InstituteShenzhen 518055China College of Materials Science and Engineering Shenzhen UniversityShenzhen 518071China

Carbon nitride has been extensively used as a visible-light photocatalyst,but it has the disadvantages of a low specific surface area,rapid electron-hole recombination,and relatively low light *** this study,single-atom Ag was successfully anchored on ultrathin carbon nitride(UTCN)via thermal polymerization,the catalyst obtained is called *** Ag hardly changed the carbon nitride's layered and porous physical *** exhibited efficient visible-light photocatalytic performances in the degradation of various recalcitrant pollutants,eliminations of 85% were achieved by visible-light irradiation for *** with Ag improved the photocatalytic performance of UTCN by narrowing the forbidden band gap from 2.49 to 2.36 e V and suppressing electron-hole pair *** addition,Ag doping facilitated O_(2) adsorption on UTCN by decreasing the adsorption energy from -0.2 to -2.22 e V and favored the formation of O_(2)^(·-).Electron spin resonance and radical-quenching experiments showed that O_(2)^(·-)was the major reactive species in the degradation of Acetaminophen(paracetamol,APAP).

关键词： Ag single atom Carbon nitride Photocatalysis Visible light Adsorption energy Reactive species

在线全文

学校读者我要写书评

暂无评论

大掺量粉煤灰路面基层专用水泥性能研究

武汉理工大学学报 2009年第12期31卷 15-19页

作者：沈卫国胡金强李瑞林周明凯王瑾王义恒武汉理工大学硅酸盐材料工程教育部重点实验室武汉430070 葛洲坝集团股份有限公司水泥厂荆门448000

研究了一种具有缓凝微膨胀性的大掺量粉煤灰路面基层稳定专用水泥,对专用水泥中石膏掺量与凝结时间、水泥强度以及涨缩性能的关系进行了实验研究。专用水泥凝结时间长,随着石膏掺量的增加,水泥的凝结时间和强度都有一个最大值,SO3适宜... 详细信息

研究了一种具有缓凝微膨胀性的大掺量粉煤灰路面基层稳定专用水泥,对专用水泥中石膏掺量与凝结时间、水泥强度以及涨缩性能的关系进行了实验研究。专用水泥凝结时间长,随着石膏掺量的增加,水泥的凝结时间和强度都有一个最大值,SO3适宜含量为4.4%。熟料掺量减少,水泥凝结时间延长,强度逐渐降低,当掺量小于45%后强度降低明显;随着SO3含量增加,这种水泥的净膨胀值增加,专用水泥的微膨胀性可以在一定程度上改善路面基层材料的抗裂性能。

关键词：路面基层专用水泥粉煤灰凝结时间膨胀抗裂性能

Numerical and Experimental Study on Aerodynamic Performance of Small Axial Flow Fan with Splitter Blades

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2013年第4期22卷 333-339页

作者： Zhu Lifu jin yingzi Li yi jin Yuzhen wang Yanping Zhang Li The Province Key Laboratory of Fluid Transmission Technology Zhejiang Sci-Tech University

To improve the aerodynamic performance of small axial flow fan, in this paper the design of a small axial flow fan with splitter blades is studied. The RNG k-e turbulence model and SIMPLE algorithm were applied to the steady simulation calculation of the flow field, and its result was used as the initial field of the large eddy simulation to calculate the unsteady pressure field. The FW-H noise model was adopted to predict aerodynamic noise in the six monitoring points. Fast Fourier transform algorithm was applied to process the pressure signal. Experiment of noise testing was done to further investigate the aerodynamic noise of fans. And then the results obtained from the numerical simulation and experiment were described and analyzed. The results show that the static characteristics of small axial fan with splitter blades are similar with the prototype fan, and the static characteristics are improved within a certain range of flux. The power spectral density at the six monitoring points of small axial flow fan with splitter blades have decreased to some extent. The experimental results show sound pressure level of new fan has reduced in most frequency bands by comparing with prototype fan. The research results will provide a proof for parameter optimization and noise prediction of small axial flow fans with high performance.

关键词： small axial flow fan splitter blades noise frequency

Ignition and Lean Blowout Characteristics of a Reverse-Flow Combustor for an Ultra-Compact Gas Turbine Engine

在线全文

学校读者我要写书评

暂无评论

Journal of Thermal Science 2024年第5期33卷 1897-1906页

作者： jin yi HUANG Yakun YAO Kanghong ZHANG Kai wang Yunbiao wang Donghao College of Energy and Power Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China National Key Laboratory of Transient Physics Nanjing University of Science and TechnologyNanjing 210094China Low-carbon Aerospace Power Engineering Research Center of Ministry of Education Nanjing 210016China

The flame stability limit and propagation characteristics of a reverse-flow combustor without any flame-stabilized device were experimentally investigated under room temperature and *** results indicate that it is feasible to stabilize the flame in the recirculation zones constructed by the impact jet flow from the primary holes and dilution *** flame projected area is mainly distributed in the recirculation zone upstream of the primary holes,whose presence and absence mark the ignition and *** the ignition process,the growth rate and value of the flame projected area first increase and then decrease with the inlet velocity increasing from 9.4 m/s to 42.1 m/s.A rapid reduction followed by a slow reduction of ignition and lean blowout equivalence ratios is achieved by the increased inlet *** the non-reacting fluid structure in three sections was measured,and detailed velocity profiles were analyzed to improve the understanding of the flame stabilization *** results are conducive to the design of an ultra-compact combustor.

关键词： ultra-compact combustor gas turbine reverse-flow combustor ignition lean blowout

Research on the prognosis of different types of microvessels in bladder transitional cell carcinoma

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2021年第25期9卷 7381-7390页

作者： Hai-Bo wang yi Qin jin-yi Yang Department of Urology Surgery Dalian Municipal Friendship HospitalDalian 116001Liaoning ProvinceChina Department of Science and Education Dalian Municipal Friendship HospitalDalian 116001Liaoning ProvinceChina

BACKGROUND At present,there is controversy on the role of microvessel density(MVD)in tumors as a prognostic indicator of bladder transitional cell carcinoma(BTCC).However,the MVD in tumors is simply classified based on the expression of several different vascular markers,which has not been related to analytical research on the prognosis of patients with *** To explore the classification of blood vessels in tumors and studied the relationship between MVD and the prognosis of patients with *** The tissue mass was detected by tissue microarray and immunohistochemical analysis with monoclonal antibodies against CD31,CD34,CD105,and vascular smooth muscle actin to investigate the MVD in *** measurement data are expressed as the mean±*** difference between the groups was analyzed by the t-test,the counting data were analyzed byχ2 *** Kaplan-Meier survival curve was estimated by the product-limit *** log-rank time-series test was employed to compare the tumor-free survival *** The MVD was closely related to the pathological grade,invasive depth,and prognosis of *** differences were found between grade I and grade II,grade II and grade III,superficial and invasive type,and the tumor-free survival group and the recurrence or metastasis group(P<0.01).Multivariate analysis showed that undifferentiated MVD was an independent prognostic factor for patient survival *** inverse correlation between undifferentiated tumor MVD and differentiated tumor MVD in BTCC was also *** The classification of blood vessels in BTCC could act as an important prognostic indicator and may also be of great significance in the treatment of cancer.

关键词： Bladder transitional cell carcinoma Microvessel density Morphological characteristics Blood vessels Prognosis

SVD-Based Low-Complexity Methods for Computing the Intersection of K≥2 Subspaces

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

Chinese Journal of Electronics 2019年第2期28卷 430-436页

作者： YAN Fenggang wang Jun LIU Shuai jin Ming SHEN yi School of Information and Electrical Engineering Harbin Institute of Technology at Weihai School of Astronautics Harbin Institute of Technology

Given the orthogonal basis(or the projections) of no less than two subspaces in finite dimensional spaces, we propose two novel algorithms for computing the intersection of those subspaces. By constructing two matrices using cumulative multiplication and cumulative sum of those projections, respectively, we prove that the intersection equals to the null spaces of the two matrices. Based on such a mathematical fact,we show that the orthogonal basis of the intersection can be efficiently computed by performing singular value decompositions on the two matrices with much lower complexity than most state-of-the-art methods including alternate projection method. Numerical simulations are conducted to verify the correctness and the effectiveness of the proposed methods.

关键词： Orthogonal projection Cumulative sum Cumulative multiplication Singular value decomposition Intersection

Probabilistic analysis of secant piles with random geometric imperfections

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2021年第3期15卷 682-695页

作者： yi YANG Dalong jin Xinggao LI Weilin SU Xuyang wang Key Laboratory of Urban Underground Engineering of the Education Ministry School of Civil EngineeringBeijing Jiaotong UniversityBeijing100044China

The failure to achieve minimum design overlap between secant piles compromises the ability of a structure to perform as designed,resulting in water leakage or even ground *** establish a more realistic simulation and provide guidelines for designing a safe and cost-effective secant-pile wall,a three-dimensional model of a secant pile,considering the geometric imperfections of the diameter and direction of the borehole,is *** ultrasonic cross-hole test was performed during the construction of secant piles in a launching shaft in Beijing,*** on the test results,the statistical characteristics of the pile diameters and orientation parameters were *** taking the pile diameter D,inclination angleβ,and azimuth angleαas random variables,Monte Carlo simulations were performed to discuss the influence of different design parameters on the probability density functions of the overlap of secant *** obtained results show that the randomness of the inclination angle and pile diameter can be well described by a normal distribution,whereas the azimuth angle is more consistent with a uniform *** integrity of the secant-pile wall can be overestimated without considering the uncertainty of geometric *** failure of the secant-pile wall increases substantially with increasing spatial variability in drilling inclination and diameter.A design flowchart for pile spacing under the target safety level is proposed to help engineers design a safe and economical pile wall.

关键词： secant piles ultrasonic cross-hole testing probabilistic analysis reliability-based design random imperfections

Controls of Tectonics on both Sedimentary Sequences and Petroleum Systems in Tarim Basin, Northwest China

在线全文

学校读者我要写书评

暂无评论

Petroleum Science 2007年第2期4卷 1-9页

作者： Chen Shuping wang yi jin Zhijun Department of Earth Sciences China University of Petroleum Beijing 102249 China Petroleum Exploration and Production Research Institute Sinopec Company Ltd. Beijing 100083 China

Various orders of sequences were recognized in the Tarim Basin from unconformities. Three mega-sequence groups, six mega-sequences, sixteen super-sequences and forty-two sequences were determined from the Sinian to the Quaternary. The mega-sequences and super-sequences were in accordance with the locally tectonic events occurring in both the north and the south margins of the Tarim plate. The global sea level changes only worked to control formations in the tectonically stable periods or in the low order sequences. The sequences had close relationship to the source rocks, reservoirs and cap rocks, and the tectonic events determined the migration, accumulation, and preservation of the hydrocarbon. The three mega-sequence group cycles, including the early cycle-the Sinian-middle Devonian, the middle cycle-the upper Devonian-Triassic, and the late cycle-the Jurassic-Quaternary, corresponded to three reservoir formation cycles. So, it can be concluded that the local tectonic events controlled both the sequences and the distribution of oil and gas in the Tarim Basin.

关键词： Sequence stratigraphy tectonics petroleum geology

Effects of magnesium and copper additions on tensile properties of Al-Si-Cr die casting alloy under as-cast and T5 conditions

在线全文

学校读者我要写书评

暂无评论

China Foundry 2023年第1期20卷 12-22页

作者： Hong-yi Zhan yi-wu Xu Pan wang Jian-feng wang jin-ping Li Le-peng Zhang General Motors Global Research&Development China Science LaboratoryShanghai 201206China School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China General Motors(China)Investment Co. Ltd.Shanghai 201206China China International Intellectech Corporation(CIIC) Beijing 100004China

Aluminum high pressure die casting(HPDC)technology has evolved in the past decades,enabling stronger and larger one-piece casting with significant part *** also offers a higher design freedom for more mass-efficient thin-walled body *** body structures that require excellent ductility and fracture toughness to be joined with steel sheet via self-piercing riveting(for instance,shock towers and hinge pillars,etc.),a costly T7 heat treatment comprising a solution heat treatment at elevated temperatures(450℃-500℃)followed by an over-ageing heat treatment is needed to optimize microstructure for meeting product *** enable cost-efficient mass production of HPDC body structures,it is important to eliminate the expensive T7 heat treatment without sacrificing mechanical *** die cast alloy chemistry is a potential solution to improve fracture toughness and ductility of the HPDC *** present study intends to tailor the Mg and Cu additions for a new Al-Si-Cr type die casting alloy(registered as A379 with The Aluminum Association,USA)to achieve the desired tensile properties without using T7 heat *** was found that Cu addition should be avoided,as it is not effective in enhancing strength while degrades tensile *** addition is very effective in improving strength and has minor impact on tensile *** investigated Al-Si-Cr alloy with a nominal composition of Al-8.5wt.%Si-0.3wt.%Cr-0.2wt.%Fe shows comparable tensile properties with the T7 treated AlSi10MnMg alloy which is currently used for manufacturing shock towers and hinge pillars.

关键词： Al-Si alloy intermetallics high pressure die casting tensile property T7 heat treatment

Energy-based dynamic parameter identification for Pasternak foundation model

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2021年第3期20卷 631-643页

作者： wang-Xi Zhang Wei-Lei Lv jin-yi Zhang Xiong wang Hyeon-Jong Hwang Wei-Jian yi College of Civil Engineering Hunan UniversityChangsha 410082China Hunan Provincial Key Lab on Diagnosis for Engineering Structures Hunan UniversityChangsha 410082China School of Civil Engineering Hunan University of Science and TechnologyXiangtan 411201China School of Architecture Konkuk University120 Neungdong-roSeoul 05029Korea

Parameter identification of Pasternak foundation models(PFM)is never satisfactory,which discourages the application and popularization of *** the present study,an energy-based model to predict the dynamic foundation coefficients was proposed using the vibration kinetic energy and potential energy of a Pasternak foundation-rigid plate *** the basis of the Pasternak foundation,the relationship among the natural frequency,dynamic foundation coefficients,rigid plate configuration,and vibrating soil equivalent mass per unit area was *** obtain the natural frequencies of the Pasternak foundation-rigid plate system,dynamic tests were *** two or more dynamic test results of various rigid plates on a foundation,a set of equations of dynamic foundation coefficients was set up to directly identify the foundation coefficients and equivalent mass per unit area of vibrating *** feasibility of the proposed method was verified by comparing it with the outdoor and indoor test results and finite element analysis *** the proposed method is used to obtain the dynamic parameters,PFM can be generalized and applied more widely in engineering practice.

关键词： Pasternak foundation dynamic tests vibrating soil mass dynamic foundation coefficients dynamic characteristics