检索结果-南通市图书馆

MXene terminating groups=O,–F or–OH,–F or=O,–OH,–F,or=O,–OH,–Cl?

Journal of energy Chemistry 2023年第1期76卷 90-104,I0003页

作者： Tariq Bashir Sara Adeeba Ismail Jiaqi Wang Wenhao Zhu Jianqing Zhao Lijun Gao college of energy Soochow Institute for Energy and Materials InnovationsSoochow UniversitySuzhou 215006JiangsuChina

MXenes are a novel family of two-dimensional(2D)materials that are fast gaining popularity due to their versatile *** surfaces of these materials are often functionalized by negatively charged terminal groups,such as=O,OH,and F during their synthesis,and it has been hypothesized that regulating the surface terminators enables to control the material ***,there is still a large gap between computational and experimental investigations regarding comprehending the surface functional *** with mixed terminations are consistently synthesized in experiments,although pure terminated surfaces are predicted by computational *** we summarized the nature of chemical bonding in transition metal carbide materials(MXenes)by1H and19F nuclear magnetic resonance(NMR),Raman,X-ray absorption near edge structure(XANES),extended X-ray absorption fine structure(EXAFS),ultraviolet photoelectron spectroscopy(UPS),X-ray photoelectron spectroscopy(XPS)/scanning transmission electron microscopy(STEM),and thermogravimetric analysis-mass spectrometry(TGA-MS)*** literature reveals that=O,–OH,–F,and–Cl are typical MXene surface ***,recent comparative investigations on the valence band intensity distribution in MXenes reveal that the–OH cannot be considered an intrinsic termination species in *** surface terminals(=O,–OH,–F,and–Cl)of several MXenes,particularly V2CTxand Ti3C2Tx,will be identified and quantified *** have also discussed different etching approaches for the synthesis of MXene,the dependence of MXene conductivity on MXene terminating groups,and the emission of various gaseous products that evolved during its chemical *** paper provides significance,especially in the field of energy conversion and storage materials,where the intercalation process is crucial.

关键词： MXene surface terminating groups Characterization Conductivity Oxidation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Stability Prediction in Smart Grid Using PSO Optimized XGBoost Algorithm with Dynamic Inertia Weight Updation

引用

Computer Modeling in Engineering & Sciences 2025年第1期142卷 909-931页

作者： Adel Binbusayyis Mohemmed Sha Department of Software Engineering college of Computer Engineering and Sciences in Al-Kharj Prince Sattam Bin Abdulaziz UniversityAl-Kharj11942Saudi Arabia

Prediction of stability in SG(Smart Grid)is essential in maintaining consistency and reliability of power supply in grid *** the fluctuations in power generation and consumption patterns of smart cities assists in effectively managing continuous power supply in the *** also possesses a better impact on averting overloading and permitting effective energy *** though many traditional techniques have predicted the consumption rate for preserving stability,enhancement is required in prediction measures with minimized *** overcome the complications in existing studies,this paper intends to predict stability from the smart grid stability prediction dataset using machine learning *** accomplish this,pre-processing is performed initially to handle missing values since it develops biased models when missing values are mishandled and performs feature scaling to normalize independent data ***,the pre-processed data are taken for training and *** that,the regression process is performed using Modified PSO(Particle Swarm Optimization)optimized XGBoost Technique with dynamic inertia weight update,which analyses variables like gamma(G),reaction time(tau1–tau4),and power balance(p1–p4)for providing effective future stability in *** PSO attains optimal solution by adjusting position through dynamic inertial weights,it is integrated with XGBoost due to its scalability and faster computational speed *** hyperparameters of XGBoost are fine-tuned in the training process for achieving promising outcomes on *** results are measured through evaluation metrics such as MSE(Mean Square Error)of 0.011312781,MAE(Mean Absolute Error)of 0.008596322,and RMSE(Root Mean Square Error)of 0.010636156 and MAPE(Mean Absolute Percentage Error)value of 0.0052 which determine the efficacy of the system.

关键词： Smart Grid machine learning particle swarm optimization XGBoost dynamic inertia weight update

来源：

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

Gas–liquid two-phase flow in serpentine microchannel with different wall wettability

引用

Chinese Journal of Chemical Engineering 2017年第7期25卷 874-881页

作者： Yunlong Zhou He Chang Tianyu Qi energy and Power Engineering college Northeast Dianli University Institute of energy Environment and Economy Tsinghua University

Gas–liquid flow in serpentine microchannel with different surface properties exhibits drastically different flow behavior. With water and air as working fluids, the method of numerical simulation was adopted in this paper based on CLSVOF(coupled level set and volume of fluid method) multiphase model. After verifying the reasonability of the model through experiment, by changing wall properties and Re number(Re<1500), the influences of contact angle and surface roughness on flow regime and Po number were discussed. Moreover, the difference of pressure drop between curve and straight microchannel was also calculated. Beyond that, the combined effect of curve channel and wall properties on flow resistance was analyzed. This paper finds that wall properties have great influence on gas–liquid flow in microchannels not only on flow regime but also flow characteristics. Meanwhile, the pressure drop in curve microchannels is larger than straight. It is more beneficial for fluid flowing when the straight part of microchannel is hydrophilic smooth wall and curve part is hydrophobic with large roughness.

关键词： Serpentine microchannel Computational fluid dynamics Gas-liquid flow Microfluidics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Effect of C doping on the structural and electronic properties of LiFePO_4:A first-principles investigation

引用

Chinese Physics B 2012年第9期21卷 470-476页

作者：许桂贵吴景陈志高林应斌黄志高 Concord University college Fujian Normal University college of Physics and energy Fujian Normal University

Using first-principles calculations within the generalized gradient approximation （GGA）＋U framework, we inves- tigate the effect of C doping on the structural and electronic properties of LiFePO4. The calculated formation energies indicate that C doped at O sites is energetically favoured, and that C dopants prefer to occupy 03 sites. The band gap of the C doped material is much narrow than that of the undoped one, indicating better electro- conductive properties. To maintain charge balance, the valence of the Fe nearest to C appears as Fe3＋, and it will be helpful to the hopping of electrons.

关键词： LiFePO4 C doping electronic structure first-principles calculations

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Thermodynamic Modeling and Simulation of Air System Control Device

引用

Transactions of Nanjing University of Aeronautics and Astronautics 2019年第3期36卷 517-526页

作者： FU Jiangfeng LI Huacong LIU Xianwei HONG Linxiong college of Power and energy Northwestern Polytechnical University

This paper aims to obtain the thermodynamic characteristics of the air system control device sealing part in different compressor bleed air and ambient *** the basis of considering the main factors affecting the heat exchange process and simplifying the physical model of the air system control device,the thermodynamic model of air system control device is established based on the basic theory of laminar flow heat transfer and heat conduction *** the piston motion characteristics and the thermodynamic characteristics of the air system control device seal are *** simulation results show that the valve actuation dynamic time of piston is about 0.13 s in the actual working conditions,and the temperature effect on the dynamic response of the piston rod is only 5 ms when the inlet air temperature at 300 ℃ and 370 ℃.The maximum temperature of the air system control device sealing part is not more than 290 ℃ under long time working condition of compressor air *** highest temperature of the sealing part can reach up to 340 ℃ when the air flow temperature reaches the limit temperature of 370 ℃,and the longest duration working temperature limit is not more than 14 ***,the selection of control device sealing material should consider the work characteristic of instantaneous temperature limit.

关键词： aeroengine air system air bleed control device thermodynamic analysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Perspective on the R&Ds in energy chemistry systems engineering

引用

Science China Chemistry 2017年第11期60卷 1386-1390页

作者： Yingru Zhao Xiangyan Zhan Shiqi Zhang Meng Wang college of energy Xiamen UniversityXiamen 361005China

energy chemistry systems engineering （ECSE）, the applica- tion of the principles of system engineering in the field of energy chemistry, is a rapidly developing cutting-edge inter- discipline. It is used for various processes and systems in the domain of energy chemistry, dealing with problems of the efficient conversion, comprehensive utilization and comple- mentary integration of material and energy with the theories, methods and techniques of system engineering.

关键词：化学系统工程能源 DS 系统工程技术化工领域化学领域综合利用跨学科

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Investigations of tip-jet and exhaust jet development in a ducted fan

引用

Chinese Journal of Aeronautics 2019年第11期32卷 2443-2454页

作者： Lei LI Guoping HUANG Jie CHEN college of energy and Power Engineering Nanjing University of Aeronautics & Astronautics

The major aim of this work is to investigate the tip-jet and exhaust jet development in a ducted fan as well as the impact on the fan’s performance. The flow field of the ducted fans under the solidity varied from 0.2 to 0.7 are simulated by using the shear-stress transport k-x turbulence model with a refined high-quality structured grid. The exhaust jet trajectory, expanding range and the flow intersection of the jet and mainstream in the blade passage are analyzed. As the results suggest, the flow direction of the exhaust jet is deflected by the downwash and Coanda effect. The major decay region of the exhaust jet can extend at least 2 times the blade chord downstream from the blade trailing edge. The blade circulation is impacted by the tip-jet rather than the exhaust jet from the upstream when the blade tip pitch angle is 8°, and the fan solidity is less than 0.7. The blade tip thrust is reduced by the interruption from the exhaust jet when the blade tip pitch angle is 2°, and the fan solidity is larger than 0.3.

关键词： Blade circulation Blade solidity Exhaust jet Fans Tip-jet

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Minimum Time Overtaking Problem of Vehicle Handling Inverse Dynamics Based on Two Kinds of Safe Distances

引用

Chinese Journal of Mechanical Engineering 2018年第6期31卷 207-216页

作者： You-Qun Zhao Xing-Long Zhang Wen-Xin Zhang Fen Lin college of energy and Power Engineering Nanjing University of Aeronautics and Astronautics

Overtaking accidents caused by improper operations performed by a driver occur frequently. However, most stud?ies on overtaking safety have neglected research into driver control input. A novel method is proposed to obtain the driver control input during the overtaking process. Meanwhile, to improve the safety of overtaking, two types of safe distances, and the time of the overtaking are considered. Path constraints are established when considering the two types of safe distances. An optimal control model is established to solve the minimum time maneuver under multiple constraints. Using the Gauss pseudospectral method, the optimal control problem is converted into a nonlinear pro?gramming problem, which is then solved through sequential quadratic programming(SQP). In addition, the e ective?ness of the proposed method is verified based on the results of a Carsim simulation. The simulation results show that by adopting an inverse dynamics method to solve the manipulation problem of the vehicle’s minimum overtaking time, the manipulation capability of a vehicle in completing an overtaking safely within the minimum time can be obtained. This method can provide a reference for research into the active safety of manned and unmanned vehicles.

关键词： Handling inverse dynamics Safe distance Overtaking Optimal control Simulation

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Transmission loss simulation based on rectangular-pulse method and experimental evaluation of acoustic performance of perforated intake pipe

引用

Journal of Central South University 2017年第11期24卷 2605-2612页

作者： LI Heng HAO Zhi-yong ZHENG Xu LIU Lian-yun college of energy Engineering Zhejiang UniversityHangzhou 310027China

Exact simulation of the acoustic performance is essential to the engineering application for a vehicle intake system. The rectangular-pulse method based on the computational fluid dynamics approach was employed for calculating the transmission loss. Firstly, the transmission loss of the single-cavity element was simulated without any airflow, and the effects of different structural parameters on the acoustic performance were investigated comprehensively. Secondly, the static transmission loss of the perforated intake pipe was obtained by the rectangular-pulse method, which is proved to be accurate enough compared with the result by finite element method. Thirdly, under the different conditions of the mean airflow and the operating temperature, the specific transmission loss was acquired respectively. In general, the peaks of the transmission loss are shifted to the lower frequency range because of the reverse airflow, but the amplitudes are irregularly changed. Besides, when the operating temperature increases, the peaks are shifted to the higher frequencies. Finally, with the designed perforated pipe installed to the intake system, the road tests were proceeded to evaluate the actual acoustic performance, and the result indicates that the intake sound pressure level is greatly attenuated. Typically in the range of 600–1500 Hz, the insertion loss of the intake noise at the decelerating moment is almost 20 d B(A), and the overall noise is reduced more than 14.2 d B(A). In conclusion, the perforated intake pipe has been proved excellent in improving the acoustic performance of intake system and could provide the guidance for the automotive engineering application.

关键词： perforated intake pipe rectangular-pulse method transmission loss mean flow temperature road test

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Analytical investigation on mean and turbulent velocity fields of a plane jet

引用

Chinese Physics B 2011年第7期20卷 279-285页

作者：米建春冯宝平 Department of energy & Resources Engineering College of EngineeringPeking University

This paper analyses the downstream developments of the mean and the turbulent velocity fields of a plane jet. Based on the conservation of mass and the conservation of momentum, the mean-velocity half width （reflecting the jet spread rate） and the relative mass flow rate （jet entrainment） are related to the decay rate of the centreline mean velocity. These relations are not subject to self-preservation. Both analytical and experimental results suggest that the jet spread rate （K1） and the entrainment rate （K3）（and thus the decay rate K2） can be well estimated from the centreline velocity, i.e., K1 ≈ 0.6K2 and K3 ∝K2. The effect of initial mean velocity and RMS velocity profiles on the downstream mean velocity field appears to be embodied in the constants K1 K2 and K3. The analytical relationship for the self-preserving Reynolds shear stress, obtained for the first time, works well.

关键词： turbulent plane jet momentum conservation Reynolds shear stress

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：