检索结果-南通市图书馆

Friction 2021年第1期9卷 201-206页

作者： Zhuxin TIAN yu huang School of Mechanical Engineering Hubei University of Arts and ScienceXiangyang 441053China State Key Lab of Digital Manufacturing Equipment and Technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

The stiffness and dampness parameters of journal bearings are required in rectangular coordinates for analyzing the stability boundary and threshold speed of oil film *** solving the Reynolds equation,the oil film force is always obtained in polar coordinates;thus,the stiffness and dampness parameters can be easily obtained in polar ***,the transformation between the polar and rectangular coordinates of journal bearing stiffness and dampness parameters is discussed in this study.

关键词： coordinate transformation stiffness parameters dampness parameters hydrodynamic journal bearings

Non-reciprocal Sound Transmission in Electro-acoustic Systems with Time-Modulated Circuits

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2022年第6期35卷 940-948页

作者： yu huang Xiaoming Zhou Key Laboratory of Dynamics and Control of Flight Vehicle Ministry of EducationSchool of Aerospace EngineeringBeijing Institute of TechnologyBeijing100081China

Non-reciprocal sound transmission is demonstrated in an electro-acoustic system consisting of two shunt loudspeakers with time-modulated *** shunt circuit is modulated by periodically varying the resistance in time sequence,and a phase difference of time modulation is set between two sets of loudspeakers to produce a spatial *** spatiotemporal modulation of acoustic properties is thus formed to break the *** theoretical model based on the transfer-matrix method is developed to predict acoustic scatterings of electro-acoustic *** asymmetric transmission in opposite directions is disclosed by the model and is verified by time-domain simulation results based on the finite-difference time-domain *** transmission in multiple frequency bands can be created by tuning circuit parameters,showing their ability in regulating acoustic non-reciprocal *** study may provide a platform for the design of compact and non-reciprocal acoustic devices with applications to efficient noise control.

关键词： Non-reciprocity Shunt loudspeaker Time-varying circuits Spatiotemporal modulation

Underwater square-root cubature attitude estimator by use of quaternion-vector switching and geomagnetic field tensor

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

Journal of Systems Engineering and Electronics 2020年第4期31卷 804-814页

作者： huang yu WU Lihua yu Qiang Acoustic Science and Technology Laboratory Harbin Engineering UniversityHarbin 150001China Key Lab of In-fiber Integrated Optics Ministry Education of ChinaCollege of Physics and Optoelectronic EngineeringHarbin Engineering UniversityHarbin 150001China College of Automation Harbin Engineering UniversityHarbin 150001China

This paper presents a kind of attitude estimation algorithm based on quaternion-vector switching and square-root cubature Kalman filter for autonomous underwater vehicle(AUV).The filter formulation is based on geomagnetic field tensor measurement dependent on the attitude and a gyro-based model for attitude propagation. In this algorithm, switching between the quaternion and the three-component vector is done by a couple of the mathematical transformations. Quaternion is chosen as the state variable of attitude in the kinematics equation to time update, while the mean value and covariance of the quaternion are computed by the three-component vector to avoid the normalization constraint of quaternion. The square-root forms enjoy a continuous and improved numerical stability because all the resulting covariance matrices are guaranteed to stay positively semidefinite. The entire square-root cubature attitude estimation algorithm with quaternion-vector switching for the nonlinear equality constraint of quaternion is given. The numerical simulation of simultaneous swing motions in the three directions is performed to compare with the three kinds of filters and the results indicate that the proposed filter provides lower attitude estimation errors than the other two kinds of filters and a good convergence rate.

关键词： attitude estimator geomagnetic field tensor quaternion-vector switching square-root cubature Kalman filter autonomous underwater vehicle(AUV)

CBBR: enabling distributed shared memory-based coordination among mobile robots

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2016年第8期59卷 23-39页

作者： Xue JIANG yu huang State Key Laboratory for Novel Software Technology Nanjing University

Coordinating mobile robots are widely used in commercial and industrial settings to fulfill various tasks. However, to program the coordination among mobile robots is challenging. A coordination framework is needed to shield the programmer from handling low-level details of robot control and communication, while supporting flexible and cost-effective coordination at the same time. The coordination framework should also be able to well coexist with the underlying robot control. To this end, we propose the Coordination-enabled Behavior-Based Robotics(CBBR) framework. CBBR employs Distributed Shared Memory(DSM) to support coordination. The shared memory illusion built by the DSM greatly simplifies the coordination logic. Moreover,the flexible access patterns of the DSM and the rich consistency semantics of the DSM reads and writes enable flexible and cost-effective coordination. With the coordination support from the DSM, CBBR naturally extends the classical Behavior-Based Robotics(BBR) for robot control. From the perspective of robot control using BBR, the shared variables in the DSM act as the logical sensors capturing the status of coordination. The coordination algorithms are encapsulated into coordination behaviors. Thus, the physical environment status and the coordination status may trigger the physical and the coordination behaviors. The scheduling of both types of behaviors integrates coordination into robot control. We conduct a case study to demonstrate the use of CBBR. The performance measurements show the cost-effectiveness of coordinating mobile robots based on CBBR, in terms of time, space, and energy consumption.

关键词： distributed shared memory behavior-based robotics coordination behavior hierarchy behavior scheduling

A pestle and mortar approach for room temperature defect engineering in metal oxides

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Science China Materials 2018年第10期61卷 1363-1364页

作者： yu huang Department of Materials Science and Engineering University of California

Impurity doping and defect engineering represent common strategies for tailoring the electronic properties of solid-state materials,for example,controlling the carrier type and carrier concentration in semiconductor *... 详细信息

关键词：杂质掺杂固态材料材料学科学研究工作

在线全文

学校读者我要写书评

暂无评论

SnO高压结构稳定性和电学性能研究

光谱学与光谱分析 2025年第1期45卷 82-87页

作者：刘涛黄宇轩高金金王世霞上海理工大学材料与化学学院上海200093

近年来氧化亚锡(SnO)在光、电等方面的应用日益广泛,为了拓宽SnO的应用范围,采用拉曼光谱原位测试和第一性原理计算对高压条件下SnO的结构性能和电子性质进行研究。SnO表征结果:扫描电子显微镜结果显示,所选取SnO样品为具有横向尺寸的... 详细信息

近年来氧化亚锡(SnO)在光、电等方面的应用日益广泛,为了拓宽SnO的应用范围,采用拉曼光谱原位测试和第一性原理计算对高压条件下SnO的结构性能和电子性质进行研究。SnO表征结果:扫描电子显微镜结果显示,所选取SnO样品为具有横向尺寸的片状堆叠,整体呈花状;X射线衍射图谱表明,SnO样品在常温常压下晶体结构为四方晶系结构(空间群P4/nmm)。采用Mao-Bell型金刚石压腔结合原位拉曼光谱探究了SnO样品在高压下的结构性能变化,结果显示:SnO在常压有四种拉曼振动模式(A_(1g)、B_(1g)、E_(1g)和E_(2g)),分别位于211、350、113和460 cm^(-1)波数附近,其中113和211 cm^(-1)为SnO拉曼特征峰。随SnO样品体系加压至12.5 GPa,压力使Sn分子间和原子间距不断减小,导致Sn-O键长缩短,当原子发生伸缩振动时,缩短的键长使得键能增大,因此活性拉曼振动模(E_(1g)和A_(1g))均向高频方向移动;随着体系压力的继续增大,晶格发生畸变进而使得非弹性散射强度降低,峰型宽化;当加压至8 GPa时,125和216 cm^(-1)附近振动模峰急剧减小;加压至10 GPa时两个特征峰完全消失,在非静水压环境下8~10 GPa时该物质发生了非晶化;当体系加压至12.5 GPa时,谱图中仍未出现新峰,表明高压下非晶化状态稳定。随后体系进行卸压,卸压至3 GPa后SnO的E_(1g)和A_(1g)模重新出现表明样品恢复低压下的晶体结构,卸至常压特征峰强度明显分别为110和209 cm^(-1)处与加压前吻合,证明了SnO高压相变行为具有可逆性。为进一步了解压力对SnO电学性能影响,使用第一性原理方法计算了SnO在常压和实验非晶化压力(8 GPa)下的电子性质,通过非晶化前后SnO的带隙宽度变化,探究压力对SnO导电性能的影响。结果显示,在常压下SnO为具有0.43 eV带隙的间接带隙半导体,在费米能级附近态密度没有发生重叠,8 GPa时SnO显示金属性质,由于SnO O-p、Sn-s和Sn-p轨道的态密度在费米能级处重叠,导致带隙的闭合,材料发生金属化。研究结果表明SnO高压下可能产生非晶化及压力所导致的非晶化行为可逆,同时高压导致SnO发生半导体到金属的转变,拓展了SnO高压结构和电学性质的探究,为SnO高压下的应用提供进一步帮助。

关键词： SnO 拉曼光谱金刚石压腔第一性原理电子性质

Model Tests on the Effect of Dip Angles on Flow Behavior of Liquefied Sand

在线全文

学校读者我要写书评

暂无评论

Journal of Earth Science 2023年第2期34卷 381-385页

作者： Wenyang Li yu huang School of Geological Engineering and Geomatics Chang'an UniversityXi'an 710054China Department of Geotechnical Engineering College of Civil EngineeringTongji UniversityShanghai 200092China

The flow behavior of liquefied sand is reported using a self-developed testing system that enables the flow processes of liquefied sand to be studied at different slopes of the soil *** test device is mainly composed of a vibrating table,a transparent model box and a high-speed video monitoring *** tests replicated the horizontal and sloping flows of saturated sand in the model box,which can be tilted to various angles to study the flow characteristics of liquefied *** high-speed video monitoring camera captured and recorded the processes within the flowing *** increasing downslope,the strain,strain rate,duration time,and sand flow distance *** results of our experiment indicate that when selecting sites for engineering structures,the surface downslopes should be taken into account if liquefiable soils are ***,some suggestions regarding site assessment and structural design for sites prone to liquefaction were presented.

关键词： earthquake liquefied sand dip angle soil flow model test engineering geology

Weak mixing in switched systems

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2019年第12期62卷 2527-2534页

作者： yu huang Xingfu Zhong School of Mathematics Sun Yat-sen University

Given a switched system,we introduce weakly mixing sets of type 1,2 and Xiong chaotic sets of type 1,2 with respect to a given set and show that they are equivalent,respectively.

关键词： weakly mixing chaotic set switched system

Engineering cerebral folding in brain organoids

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2022年第11期17卷 2420-2422页

作者： Glen Scott yu huang Biological Engineering College of EngineeringUtah State UniversityLoganUTUSA

Valuable implement to the animal neurological models:Neurological diseases remain the largest cause of death and *** discovery of effective therapies is chiefly hindered by the lack of realistic neurological *** other tissues,it is infeasible or unethical to access primary human neural samples in *** animal models often fail to replicate the complex human-specific neuronal factors present in *** in vitro cultures lack native three-dimensional(3D)morphologies,polarity,and receptor expression,as well as tissue-level interactions(J ensen et al.,2018).

关键词： cerebral diseases

Energy consumption dynamic prediction for HVAC systems based on feature clustering deconstruction and model training adaptation

在线全文

学校读者我要写书评

暂无评论

Building Simulation 2024年第9期17卷 1439-1460页

作者： Huiheng Liu Yanchen Liu Huakun huang Huijun Wu yu huang School of Civil Engineering and Transportation Guangzhou UniversityGuangzhou510006China School of Computer Science and Cyber Engineering Guangzhou UniversityGuangzhou510006China

The prediction of building energy consumption offers essential technical support for intelligent operation and maintenance of buildings,promoting energy conservation and low-carbon *** paper focused on the energy consumption of heating,ventilation and air conditioning(HVAC)systems operating under various modes across different *** constructed multi-attribute and high-dimensional clustering vectors that encompass indoor and outdoor environmental parameters,along with historical energy consumption *** enhance the K-means algorithm,we employed statistical feature extraction and dimensional normalization(SFEDN)to facilitate data clustering and *** method,combined with the gated recurrent unit(GRU)prediction model employing adaptive training based on the Particle Swarm Optimization algorithm,was evaluated for robustness and stability through k-fold *** the clustering-based modeling framework,optimal submodels were configured based on the statistical features of historical 24-hour data to achieve dynamic prediction using multiple *** dynamic prediction models with SFEDN cluster showed a 11.9%reduction in root mean square error(RMSE)compared to static prediction,achieving a coefficient of determination(R2)of 0.890 and a mean absolute percentage error(MAPE)reduction of 19.9%.When compared to dynamic prediction based on single-attribute of HVAC systems energy consumption clustering modeling,RMSE decreased by 12.6%,R2 increased by 4.0%,and MAPE decreased by 26.3%.The dynamic prediction performance demonstrated that the SFEDN clustering method surpasses conventional clustering method,and multi-attribute clustering modeling outperforms single-attribute modeling.

关键词： HVAC system energy consumption clustering analysis deep learning model adaptation dynamic prediction