Diverse atomic structure configurations of metal-doped transition metal dichalcogenides for enhancing hydrogen evolution

Doping foreign metal atoms into the substrate of transition metal dichalcogenides(TMDs)enables the formation of diverse atomic structure configurations,including isolated atoms,chains,and clusters.Therefore,it is very important to reasonably control the atomic structure and determine the structure-activity relationship between the atomic configurations and the hydrogen evolution reaction(HER)performance.Although numerous studies have indicated that doping can yield diverse atomic structure configurations,there remains an incomplete understanding of the relationship between atomic configurations within the lattice of TMDs and their performance.Here,diverse atomic structure configurations of adsorptive doping,substitutional doping,and TMDs alloys are summarized.The structure-activity relationship between different atomic configurations and HER performance can be determined by micro-nanostructure devices and density functional theory(DFT)calculations.These diverse atomic structure configurations are of great significance for activating the inert basal plane of TMDs and improving the catalytic activity of HER.Finally,we have summarized the current challenges and future opportunities,offering new perspectives for the design of highly active and stable metal-doped TMDs catalysts.

Research on Web-Based Product Structure and Configuration Management

An enhanced system architecture of Web-based product structure and configuration management system along with its, functions are is presented. The key techniques, such as construction of object models of product structure and product configuration, hybrid approach method in product configuration management, sharing and integration of heterogeneous product data, integration with other sub-systems, are discussed too. A prototype system is developed by J2EE technology.

Design and implementation of dual-mode configurable memory architecture for CNN accelerator

With the rapid development of deep learning algorithms,the computational complexity and functional diversity are increasing rapidly.However,the gap between high computational density and insufficient memory bandwidth under the traditional von Neumann architecture is getting worse.Analyzing the algorithmic characteristics of convolutional neural network(CNN),it is found that the access characteristics of convolution(CONV)and fully connected(FC)operations are very different.Based on this feature,a dual-mode reronfigurable distributed memory architecture for CNN accelerator is designed.It can be configured in Bank mode or first input first output(FIFO)mode to accommodate the access needs of different operations.At the same time,a programmable memory control unit is designed,which can effectively control the dual-mode configurable distributed memory architecture by using customized special accessing instructions and reduce the data accessing delay.The proposed architecture is verified and tested by parallel implementation of some CNN algorithms.The experimental results show that the peak bandwidth can reach 13.44 GB·s^(-1)at an operating frequency of 120 MHz.This work can achieve 1.40,1.12,2.80 and 4.70 times the peak bandwidth compared with the existing work.

Effect of Different Types of Structural Configuration on Air Distribution in a Compact Purification Device

In some old industrial plants,in order to meet the increasingly strict requirements of pollutant emission limits,it is necessary to install the compact filtration and/or purification devices in a given narrow machine room.Different types of structural configuration might influence air distribution inside these devices.The unreasonable air distribution might lead each part of filtration or purification media to operating at largely different air flow rates.Based on a computational fluid dynamics(CFD)model,this study explores the influence of different outlet positions and different upper heights on the flow field inside chamber.The porous medium model is employed to simulate the air flow in porous media.The changing structural configurations include three positioning cases of the outlet opening and eight height cases of the upper chamber.The root mean square is defined as the non-uniformity coefficient to evaluate the uniformity of air flow distribution.The results show that the farther distance between inlet and outlet openings will bring more uniform air distribution,and the increasing height of upper chamber totally trends to exhibit more uniform air distribution.

A version management model of PDM system and its realization

Based on the key function of version management in PDM system, this paper discusses the function and the realization of version management and the transitions of version states with a workflow. A directed aeyclic graph is used to describe a version model. Three storage modes of the directed acyelic graph version model in the database, the bumping block and the PDM working memory are presented and the conversion principle of these three modes is given. The study indicates that building a dynamic product structure configuration model based on versions is the key to resolve the problem. Thus a version model of single product object is built. Then the version management model in product structure configuration is built and the application of version management of PDM syster is presented as a case.

Primary structure and configuration of tea polysaccharide

The monosaccharide composition of a tea polysaccharide (TGC) was determined by GC-MS method. Furthermore, the primary structure of tea polysaccharide and its configura-tion in the aqueous solution were investigated utilizing a combination of classical chemical methods and modern instrumental techniques including GC-MS, Proton NMR, UV and CD. The results indicate that TGC consists of 6 monosaccharides: Rha, Ara, Xyl, Glu, Man and Gal. The configuration of TGC in water solution is proposed to be an ordered helix. The possible primary structure of TGC was outlined as below: the basic structure of the main chain consists of Rha, Glu and Gal units. All three monosaccharides can potentially be connected to branch chains consisting of mainly Ara, and the linkages could be in b1→2, b 1→3, b 2→3 forms. When branch chain is absent in the basic structure of the main chain the linkage consists of only b 1→3; Xyl exists at the terminal end of either the main chain or the branch chain with b 1→ linkage.

Key Techniques for the Development of Web-Based PDM System

Some key techniques for the development of web-based product data management （PDM） system are introduced. The four-tiered B/S architecture of a PDM system-BITPDM is introduced first, followed by its design and implementation, including virtual data vault, flexible coding system, document management, product structure and configuration management, workflow/process and product maturity management. BITPDM can facilitate the activities from new product introduction phase to manufacturing, and manage the product data andtheir dynamic changing history. Based on Microsoft. NET, XML, web service and SOAP techniques, BITPDM realizes the integration and efficient management of product information.

Computer Aided Design of Geodesic Forms

Geodesic forms constitute an important family of structural systems. They are efficient and appealing and are employed frequently for dome structures. Data generation for geodesic forms has always been a difficult task, from the days of hand data generation using tables of coefficients to today＇s specially written computer programs with many limitations and shortcomings. Formex algebra is a mathematical system which is ideally suited for data generation and configuration processing. The objective of the present paper is to introduce the concepts of formex algebra through which data generation for polyhedric and geodesic forms can be handled with ease and elegance.

Effect of mixing section configurations on combustion efficiency of Mg-CO_(2)Martian ramjet

Experiments were conducted to determine the effects of the mixing section configurations on the Mg-CO_(2)Martian ramjet combustion efficiency.It was carried out at a mainstream mass flow rate of 110 g/s and a temperature of 810 K.The chamber pressure was measured under different configurations and Oxidizer to Fuel(O/F)ratios.Results showed that the engine achieved self-sustaining combustion and worked stably during experiments.The pre-combustion chamber is needed to increase the combustion efficiency and promote the full combustion of the powder.After the configuration of the pre-combustion chamber,the best combustion efficiency reached 80%when radial powder injection and lateral carbon dioxide intake were used.In addition,the O/F ratio in the pre-combustion chamber decreased from 0.67 to 0.31,resulting in an 8%increase in the combustion efficiency.It was speculated that different mixing section configurations and the variations in an O/F ratio within the pre-combustion chamber impacted the combustion efficiency and in essence,all affected the flow velocity and residence time of the two-phase flow in the com-bustion chamber.

Integrated batteries layout and structural topology optimization for a solar-powered drone

The purpose of this paper is to demonstrate an integrated optimization scheme for a solar-powered drone structure.Consider a primary beam in the wing of large aspect ratio,where 100 lithium batteries are assembled.In the proposed integrated optimization,the batteries are considered here as parts of the load-carrying structure.The corresponding mechanical behaviors are simulated in the structural design and described with super-elements.The batteries layout and the structural topology are then introduced as mixed design variables and optimized simultaneously to achieve an accordant load-carrying path.Geometrical nonlinearity is considered due to the large deformation.Different periodic structural configurations are tested in the optimization in order to meet the structural manufacturing and assembly convenience.The optimized designs are rebuilt and tested in different load cases.Maintaining the same structural weight,the global mechanical performances are improved greatly compared with the initial design.

Composite structural modeling and tensile mechanical behavior of graphene reinforced metal matrix composites

Owing to its distinguished mechanical stiffness and strength, graphene has become an ideal reinforcing material in kinds of composite materials. In this work, the graphene（reduced graphene oxide） reinforced aluminum（Al）matrix composites were fabricated by flaky powder metallurgy. Tensile tests of pure Al matrix and graphene/Al composites with bioinspired layered structures are conducted.By means of an independently developed Python-based structural modeling program, three-dimensional microscopic structural models of graphene/Al composites can be established, in which the size, shape, orientation, location and content of graphene can be reconstructed in line with the actual graphene/Al composite structures. Elastoplastic mechanical properties, damaged materials behaviors, grapheneAl interfacial behaviors and reasonable boundary conditions are introduced and applied to perform the simulations. Based on the experimental and numerical tensile behaviors of graphene/Al composites, the effects of graphene morphology,graphene-Al interface, composite configuration and failure behavior within the tensile mechanical deformations of graphene/Al composites can be revealed and indicated, respectively.From the analysis above, a good understanding can be brought to light for the deformation mechanism of graphene/Al composites.

Development of impact resistant 3D printed multi-layer carbon fibre reinforced composites by structural design

In this study,a high impact resistant multi-layered composite consisting of continuous carbon fibre/nylon(CCF)and short carbon fibre/nylon(SCF)layers is developed via 3D printing technology.The effect of CCF/SCF layers configuration on the impact resistance is investigated by low-velocity impact test,and the impact failure mechanism of the 3D printed composites is explored by microscopic observations and finite element(FE)simulation analysis.The results show that the 3D printed multi-layered composite with SCF layers distributed in the middle(HFA)exhibits higher impact resistant performance than the specimens with alternating SCF/CCF layers(HFB)and CCF layers distributed in the middle(HFC).The effect of CCF/SCF layers proportion on the impact performance is also studied by FE simulation,and the results show that the specimen with a CCF/SCF proportion of 7.0 exhibits the highest impact strength.