检索结果-南通市图书馆

Experimental investigation on the reformation and strength weakening of hard limestone by acidizing

在线全文

学校读者我要写书评

暂无评论

International Journal of Mining Science and Technology 2022年第5期32卷 965-979页

作者： Bingxiang huang Mingxiao Hou xinglong Zhao Yuekun xing State Key Laboratory of Coal Resources and Safe Mining China University of Mining and TechnologyXuzhou 221116China

Several derivative disasters such as ground pressure disasters and methane explosions can be caused by the hard roof in coal *** limestone roofs with fine integrity and extreme hardness,collapse is difficult and the effect of conventional roof control methods is *** reformation is an effective way to weaken the strength of roof strata based on acid-rock *** this study,the rock strength damage law and acid reaction characteristics were tested by the limestone acidification ***,the strength degradation mechanism of limestone under the acidity effect was *** results show that the acid corrosion characteristics of limestone are obvious,as numerous mineral grains generate voids under the effects of acid corrosion,and more defects are formed *** acid-rock reaction is the most intense at the early stage and then gradually reaches dynamic equilibrium,and the acid corrosion rate of limestone is 4.24%(10%HCl,360 min).The hard limestone is damaged after ***,the internal cracks can be induced to rapid initiation and unstable propagation under load,which reduces the strain required for rock failure by 33.33%.The failure morphology is more complicated,and the uniaxial compressive strength and elastic modulus decrease by 52.42%and 34.44%*** strength weakening of hard roof after acidification is due to the defects such as intergranular cracking caused by the corrosion of rock crystals under acidity effect,which accelerate the initiation and propagation of internal cracks with external ***,acidification induced the deterioration of rock mechanical properties by reforming the roof *** feasibility of acidizing reformation method to control hard roof is confirmed in this study.

关键词： Hard roof Acidizing reformation Strength weakening Acid-rock reaction Corrosion

Alamouti code based on block repetition in FBMC/OQAM systems

在线全文

学校读者我要写书评

暂无评论

Digital Communications and Networks 2022年第1期8卷 58-63页

作者： Dejin Kong xing Zheng Yukang Tian tao Jiang Yue Zhang School of Electronic and Electrical Engineering Wuhan Textile UniversityWuhanChina State Key Laboratory of New Textile Materials and Advanced Processing Technologies Wuhan Textile UniversityWuhanChina Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhanChina Department of Engineering University of LeicesterLeicesterLEI 7RHUK

In this paper,we address the Alamouti code in Filter-Bank Multicarrier with Offset Quadrature Amplitude Modulation(FBMC/OQAM)and propose a novel block-wise Alamouti code,in which a repeated block is designed to eliminate the imaginary interference among FBMC/OQAM *** proposed approach exhibits a higher spectral efficiency than the conventional block-wise Alamouti scheme,as only one column of zero symbols is used as a guard interval instead of ***,compared to the conventional scheme,the bit error ratio is improved in the proposed block-wise Alamouti,as the assumption on channel invariance at two adjacent sub-carriers is not *** results indicate that,with a significantly reduced overhead,the proposed Alamouti scheme achieves better performance over the conventional block-wise Alamouti scheme.

关键词： Alamouti Filter-bank multicarrier Block repetition Imaginary interference

D and B Meson Decays into Vlv and PV

在线全文

学校读者我要写书评

暂无评论

Chinese Physics Letters 1991年第6期8卷 274-277页

作者： GUO Xinheng huang tao Institute of High Energy Physics Beijing 100039

The reasonable wavefunctions of the vector mesonsρ,K^(*)and D^(*)are pro-posed and their properties are *** calculated the decay processes D,B→Vlv and *** of the results of our model with those of the Bauer-Stech-Wirbel(BSW)model and the experimental data are *** also obtained the upper limit of V_(ub) which is smaller than that of BSW model.

关键词： model decay limit

Fault-tolerant stator flux oriented decoupling control for dual three-phase permanent magnet motor without diagnosis and reconfiguration

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(Technological Sciences) 2023年第11期66卷 3206-3218页

作者： huang LinSen ZHAO WenXiang tao tao CUI Jia ZHANG Qiang School of Electrical and Information Engineering National Center for International Research on Structural Health Management of Critical ComponentsJiangsu UniversityZhenjiang 212013China

In this paper,the fault-tolerant capability of the existing stator-flux-oriented decoupling control(SFOC)for the DTP-PM motor is investigated,and a simple fault-tolerant SFOC is further designed to enhance fault ***,the mathematical model of the DTP-PM motor in the stator-flux-oriented rotating coordinate system is *** SFOC is proposed to guarantee healthy operation performance,considering torque,flux linkage,and harmonic ***,the coupling relationship under open-phase conditions is *** assessed result shows that the coupling relationship between the harmonic and fundamental components results in conflicts and poor post-fault ***,the proposed SFOC includes an automatic deactivation module to detect conflicts with a variable *** conflicted harmonic current controllers can be excluded ***,fault-tolerant control can be remedied without diagnosing the specific fault scenario,and excellent faulttolerant capability can be ***,experiments on a DTP-PM motor are carried out to verify the feasibility and effectiveness of the proposed strategy.

关键词： dual three-phase motor stator flux orientation decoupling control fault-tolerant control open-phase fault

Preparation of novel Ni-Ir/γ-Al_2O_3 catalyst via high-frequency cold plasma direct reduction process

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2009年第1期18卷 35-38页

作者： Liqiong huang Wei Chu tao Zhang YongxiangYin Xumei tao Department of Chemical Engineering Sichuan University Chengdu 610065 Sichuan China Dalian Institute of Chemical Physics Chinese Academy of Sciences Dalian 116023 Liaoning China

The novel Ni-Ir/γ-Al2O3 catalyst, denoted as NIA-P, was prepared by high-frequency cold plasma direct reduction method under ambient conditions without thermal treatment, and the conventional sample, denoted as NIA-CR, was prepared by impregnation, thermal calcination, and then by H2 reduction method. The effects of reduction methods on the catalysts for ammonia decomposition were studied, and they were characterized by XRD, N2 adsorption, XPS, and H2-TPD. It was found that the plasma-reduced NIA-P sample showed a better catalytic performance, over which ammonia conversion was 68.9%, at T = 450℃, P = 1 atm, and GHSV = 30, 000 h^-1. It was 31.7% higher than that of the conventional NIA-CR sample. XRD results showed that the crystallite size decreased for the sample with plasma reduction, and the dispersion of active components was improved. There were more active components on the surface of the NIA-P sample from the XPS results. This effect resulted in the higher activity for decomposition of ammonia. Meanwhile, the plasma process significantly decreased the time of preparing catalyst.

关键词： high-frequency cold plasma jet Ni-Ir catalyst direct reduction ammonia decomposition hydrogen production

Providing Guaranteed Network Performance across Tenants:Advances,Challenges and Opportunities

在线全文

学校读者我要写书评

暂无评论

China Communications 2021年第2期18卷 152-174页

作者： Chengyuan huang Jiao Zhang tao huang Yunjie Liu State Key Laboratory of Networking and Switching Technology BUPTBeijingChina Purple Mountain Laboratories NanjingChina

The varied network performance in the cloud hurts application *** increases the tenant’s cost and becomes the key hindrance to cloud *** is because virtual machines(VMs)belonging to one tenant can reside in multiple physical servers and communication interference across tenants occasionally occurs when encountering network *** order to prevent such unpredictability,it is critical for cloud providers to offer the guaranteed network performance at tenant *** a critical issue has drawn increasing attention in both academia and *** elaborate mechanisms are proposed to provide guaranteed network performance,such as guaranteed bandwidth or bounded message delay across ***,due to the intrinsic complexities and limited capabilities of commodity hardware,the deployment of these mechanisms still faces great challenges in current cloud ***,with the rapid development of new technologies,there are new opportunities to improve the performance of existing works,but these possibilities are not under full discussion ***,in this paper,we survey the latest development of the network performance guarantee approaches and summarize them based on their ***,we explore and discuss the possibilities of using emerging technologies as knobs to upgrade the performance or overcome the inherent shortcomings of existing *** hope this article will help readers quickly Received:Apr.07,2020 Revised:Oct.23,2020 Editor:Haifeng Zheng understand the causes of the problems and serve as a guide to motivate researchers to develop innovative algorithms and frameworks.

关键词： cloud computing network performance guaranteed bandwidth guaranteed delay

Global patterns in above-ground net primary production and precipitation-use efficiency in grasslands

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2018年第8期15卷 1682-1692页

作者： QIN Xiao-jing HONG Jiang-tao MA xing-xing WANG Xiao-dan Key Laboratory of Mountain Surface Processes and Ecological Regulation Institute of Mountain Hazards and EnvironmentChinese Academy of ScienceChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China College of Urban and Environment Sciences Shanxi Normal UniversityLinfen 041000China

The above-ground net primary production(ANPP) and the precipitation-use efficiency(PUE) regulate the carbon and water cycles in grassland ecosystems, but the relationships among the ANPP, PUE and precipitation are still controversial. We selected 717 grassland sites with ANPP and mean annual precipitation(MAP) data from 40 publications to characterize the relationships ANPP–MAP and PUE–MAP across different grassland types. The MAP and ANPP showed large variations across all grassland types, ranging from 69 to 2335 mm and 4.3 to 1706 g m^(-2), respectively. The global maximum PUE ranged from 0.19 to 1.49 g m^(-2) mm^(-1) with a unimodal pattern. Analysis using the sigmoid function explained the ANPP–MAP relationship best at the global scale. The gradient of the ANPP–MAP graph was small for arid and semi-arid sites(MAP <400 mm). This study improves our understanding of the relationship between ANPP and MAP across dry grassland ecosystems. It provides new perspectives on the prediction and modeling of variations in the ANPP for different grassland types along precipitation gradients.

关键词： Litter decomposition Alpine communities Tea bag index Carbon cycle Above-ground net primary production Precipitation-use efficiency Sigmoid function Precipitation gradients

A catastrophic debris flow in the Wenchuan Earthquake area,July 2013：characteristics,formation,and risk reduction

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2017年第1期14卷 15-30页

作者： HU tao huang Run-qiu State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of Technology Chengdu 610059 China

In the Wenchuan Earthquake area,many co-seismic landslides formed blocking-dams in debris flow channels. This blocking and bursting of landslide dams amplifies the debris flow scale and results in severe catastrophes. The catastrophic debris flow that occurred in Qipan gully(Wenchuan,Southwest China) on July 11,2013 was caused by intense rainfall and upstream cascading bursting of landslide dams. To gain an understanding of the processes of dam bursting and subsequent debris flow scale amplification effect,we attempted to estimate the bursting debris flow peak discharges along the main gully and analyzed the scale amplification process. The results showed that the antecedent and triggering rainfalls for 11 July debris flow event were 88.0 mm and 21.6 mm,respectively. The event highlights the fact that lower rainfall intensity can trigger debris flows after the earthquake. Calculations of the debris flow peak discharge showed that the peak discharges after the dams-bursting were 1.17–1.69 times greater than the upstream peak discharge. The peak discharge at the gully outlet reached 2553 m^3/s which was amplified by 4.76 times in comparison with the initial peak discharge in the upstream. To mitigate debris flow disasters,a new drainage channel with a trapezoidal V-shaped cross section was proposed. The characteristic lengths(h1 and h2) under optimal hydraulic conditions were calculated as 4.50 m and 0.90 m,respectively.

关键词： Disaster characteristics Formation mechanisms Risk reduction Debris flow Wenchuan Earthquake Blocking dam

Extension of the pressure correction method to zero-Mach number compressible flows

在线全文

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2009年第6期52卷 1583-1595页

作者： HE YaLing huang Jing tao YuBing tao WenQuan State Key Laboratory of Multiphase Flow in Power Engineering School of Energy&Power EngineeringXi’an Jiaotong UniversityXi’an 710049China

In the present paper,the classical pressure correction method was extended into low Mach number compressible flow regime by integrating equation of state into SIMPLE *** self-developed code based on this algorithm was applied to predicting the lid-driven cavity flow and shock tube prob-lems,and the results showed good agreement with benchmark solutions and the Mach number can reach the magnitude of as low as *** attenuation of sound waves in viscous medium was then *** results agree well with the analytical solutions given by theoretical *** demonstrated that the present method could also be implemented in acoustics field simulation,which is crucial for thermoacoustic simulation.

关键词： thermoacoustic engine pressure correction method low Mach number compressible flow