Fabrication and Interface Structural Behavior of Mg/Al Thickness-Oriented Bonding Sheet via Direct Extrusion

Lei Gao,Feng Li,Ye Wang,Xing Mao Xiao,Peng Da Huo 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

Solid-state bonding of heterogeneous materials is one of the effective ways to achieve light weight. An extrusion formingprocess for Mg/Al thickness-oriented bonding sheet was carried out. Due to triaxial compressive stress in the extrusion container,the AZ31 and AA6061 billets were deformed and the bonding and forming of Mg/Al thickness-oriented sheet can berealized by this method. The observation results of the bonding position by using XRD, SEM and EDS showed that: at theforming temperature with 360–420 °C, it had a good bonding interface, and the width of the transition layer increased withthe increase of the forming temperature. The presence of brittle intermetallic compounds in the transition layer indicated thatmetallurgical bonding had occurred at the interface. Considering all factors comprehensively, when the forming temperaturewas 390 °C, the bonding quality was appropriate. Its tensile-shear strength was 42 MPa, the width of the interface transitionlayer was about 10 μm, and the microhardness was about 164.3 HV. This method provided scientific guidance and technicalreserves for green forming of Mg/Al sheets.

A Study of the Satisfaction with the operation of design courses-Based on PJBL(Project Based Learning): An analysis of a University of Applied Sciences in China

WANG LEI(LEI WANG),Choi Wonjae(Wonjae Choi) 한국스마트미디어학회 2023 스마트미디어저널 Vol.12 No.5

As the definition and role of design changes over time with the times and society, design education needs to update teaching methods to match it. The course design in this study began with an optimisation of the learning model based on previous research and analysis, followed by in-depth interviews, the application of the interview results to the final curriculum design, and finally a questionnaire to verify the positive effects of this teaching model. This teaching model has been applied to teach a pilot class in a university of applied sciences in China. The main characteristics of the course design are Project-Based Learning (PJBL) oriented, team cooperation centric, and an educational model developed based on peer assessment. In every stage of the UI design course, realistic project simulations are adopted, enhancing students' abilities through practical experience, teamwork, and peer assessment. The innovation lies in validating the effectiveness and advantages of this model at every stage of the UI design course, innovating existing teaching methods, optimizing learning models, and combining practice with evaluation. This research found that a project-oriented team course design based on PJBL has a high degree of effectiveness and relevance in each stage of the UI design course, significantly improving students' overall competence. It is expected that the results of this study can be applied in various ways to the course design of the courses that similar to design majors.

LiFePO₄ quantum-dots composite synthesized by a general microreactor strategy for ultra-high-rate lithium ion batteries

Wang, Bo,Xie, Ying,Liu, Tong,Luo, Hao,Wang, Bin,Wang, Chunhui,Wang, Lei,Wang, Dianlong,Dou, Shixue,Zhou, Yu Elsevier 2017 Nano energy Vol.42 No.-

<P><B>Abstract</B></P> <P>Due to the relatively slow, diffusion-controlled faradaic reaction mechanisms of conventional LiFePO<SUB>4</SUB> (LFP) materials, which is hard to deliver satisfied capacity for high rate applications. In this work, ultrafine LFP quantum dots (LFP-QDs) co-modified by two types of carbonaceous materials - amorphous carbon and graphitized conductive carbon (graphene) have been successfully synthesized through a novel microreactor strategy. Because of the very limited area constructed by the dual-carbon microreactor for the growth of LFP crystal, it's demension was furthest suppressed to a very small level (~ 6.5nm). Such a designed nano-composite possesses a large specific surface area for charge adsorption and abundant active sites for faradaic reactions, as well as ideal kinetic features for both electron and ion transport, and thus exhibits ultra-fast, surface-reaction-controlled lithium storage behavior, mimicking the pseudocapacitive mechanisms for supercapacitor materials, in terms of extraordinary rate capability (78mAhg<SUP>−1</SUP> at 200C) and remarkable cycling stability (~ 99% over 1000 cycles at 20C). On the other side, due to the quasi-2D structure of the synthesized LFP-QDs composite, which can be used as the basic unit to further fabricate free-standing film, aerogel and fiber electrode without the addition of binder and conductive agent for different practical applications. In addition, to deeper understand its electrochemical behavior, a combined experimental and density functional theoretical (DFT) calculation study is also introduced.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A general microreactor strategy has been developed for structure-optimized Li-contained electrode materials. </LI> <LI> Ultrafine LiFePO<SUB>4</SUB> quantum dots are first reported through the designed microreactor strategy. </LI> <LI> The synthesized G/LFP-QDs@C exhibits ultra-fast, surface-reaction-controlled Li storage behavior. </LI> <LI> A combined experimental and DFT calculation study is introduced to reveal the energy storage mechanism of G/LFP-QDs@C. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Ultrafine LiFePO<SUB>4</SUB> quantum dots (~ 6.5nm) co-modified by two types of carbonaceous materials - amorphous carbon and graphitized conductive carbon (graphene) have been successfully synthesized through a novel microreactor strategy, which exhibit ultra-fast, surface-reaction-controlled energy storage behavior, mimicking the pseudocapacitive mechanisms for supercapacitor materials, in terms of excellent rate capability and outstanding cycling stability.</P> <P>[DISPLAY OMISSION]</P>

Research on Large‑scale Photovoltaic Planning Based on Risk Assessment in Distribution Network

Lei Wang,Minyu Yuan,Fan Zhang,Xuli Wang,Jing Ma,Lei Dai,Xianjun Qi,Rui Bi 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.3

Risks caused by large amounts of distributed photovoltaic (PV) feeding into distribution networks, have an impact on PV planning, which has become a critical consideration for distribution networks’ operation. In this paper, a large-scale PV planning method is proposed which based on risk assessment in distribution networks. Cluster division is used to group large-scale distributed PVs. A risk assessment is performed on the distribution network, considering the correlation between PVs and loads. The efects of load fuctuations, PV quantity, capacity and location on the operational risk of the distribution network are analyzed and discussed. A large-scale PV planning model is established with the goal of maximizing the comprehensive benefts, considering the penalty cost of node voltage over-limit and branch power fow over-limit risk. Finally, the genetic algorithm is used to solve the planning model. The simulation results demonstrate the efectiveness of the proposed method.

증강현실을 이용한 패턴 인식

왕레이(Wang Lei),신성윤(Wang Lei),이양원(Seong-Yoon Shin) 한국컴퓨터정보학회 2009 한국컴퓨터정보학회 학술발표논문집 Vol.16 No.2

분 논문은 카메라 장비와 마커, DB를 이용하여 문자의 색감과 모음, 자음을 인식하여 문자에 해당되는 이미지 및 영상을 HMD 및 모니터, 가정에서 사용하는 화상 카메라 등을 이용하여 보다 구체적인 정보를 전달할 수 있게 해준다. DB에는 각 텍스트의 모음과 자음에 관한 텍스트가 등록되어 있으며, 각각의 색과 텍스트를 비교하여 해당하는 이미지를 출력하게 된다. 기존의 증강현실 기법은 해당 마크에 관한 패턴을 인식하여 그에 해당하는 이미지 및 영상을 출력하는데, DB를 이용한 문자인식을 사용할 경우 사용자에게 텍스트를 인식하여 연관된 많은 정보를 제공할 수 있게 된다. 제안된 인터페이스는 다양한 모습을 어려 시야를 통해 기존의 카탈로그보다 사용자의 접근성을 향상시키고, 미리 정의된 DB에 접근하여 해당 문자에 관한 여러가지 정보를 사용자에게 전달한다. 여러 전달 매체를 이용, 가상현실 및 증강현실 등을 다양한 카탈로그 뿐만 아니라 교육 및 신문 잡지, 광고 등 문자가 등장하는 여러 분야에 활용이 가능하다.

Cosmetics Potential of the Sulfated Polysaccharides Isolated from Ecklonia maxima-Antioxidant, Antimelanogenesis, and Photoprotective Activities

Lei Wang,D. P. Nagahawatta,Thilina U. Jayawardena,Hyo-Geun Lee,You-Jin Jeon 한국식품영양과학회 2020 한국식품영양과학회 학술대회발표집 Vol.2020 No.10

ZnO Nanorod Array Modified PVDF Membrane with Superhydrophobic Surface for Vacuum Membrane Distillation Application

Wang, Manxiang,Liu, Guicheng,Yu, Hyunjin,Lee, Sang-Hyup,Wang, Lei,Zheng, Jianzhong,Wang, Tao,Yun, Yanbin,Lee, Joong Kee American Chemical Society 2018 ACS APPLIED MATERIALS & INTERFACES Vol.10 No.16

<P>The vacuum membrane distillation (VMD) is a promising technology for lots of applications. To solve the membrane fouling and wetting problems, in this paper, a novel ZnO nanorods 1<I>H</I>,1<I>H</I>,2<I>H</I>,2<I>H</I>-perfluorodecyltriethoxysilane (PDTS) modified poly(vinylidene fluoride) (PVDF) membrane with a micro/nanoscale hierarchical structure and a superhydrophobic surface has been prepared and applied to the VMD process for distilling highly salty water, for the first time. Among these, a pyrolysis-adhesion method is created to obtain the ZnO seeds and fasten them on the PVDF substrate firmly. The novel modified membrane shows a stable superhydrophobic surface with a water contact angle of 152°, easy cleaning property, excellent thermal and mechanical stability, because of the Cassie’s state caused by pocketing much air in the hydrophobized ZnO nanorods, the low surface energy of PDTS coating, and the strong adhesion between ZnO nanorods and PVDF membrane, which has built an ideal structure for VMD application. After 8 h VMD of 200 g L<SUP>-1</SUP> NaCl solution, compared to the virgin PVDF membrane, the novel membrane shows a similar permeate flux but a much higher quality permeated liquid because of its unique antifouling and antiwetting caused by the several microns gap between the feed and the membrane. Due to its easy cleaning property, the novel membrane also exhibits an excellent reusability.</P> [FIG OMISSION]</BR>

Study on the Internal Pipeline Inspection Devices with Energy Acquisition Methods

Wang Ming-Xu,차인수,Wang Yue,Bei Lei,최홍준,정경환,김동묵,김봄,오승아,Ye In Cheol,유일준 한국에너지학회 2023 에너지공학 Vol.32 No.1

The pipeline conveying natural gas must be regularly inspected by the detection device, and the cracks and corrosion condition inside the pipeline should be detected. Generally, the detection device consists of three parts: drive part, detection part and energy part. Since pipeline transportation is long-distance transportation and cannot realize wired detection, the energy part needs to provide enough electric energy for the detection part to meet the energy consumption of the detection part. The method of obtaining energy for the energy part is very important. In this paper, the energy part is studied, and an efficient energy part is designed. By analyzing the change law of the positive pressure on the inner wall of the energy acquisition wheel on the pipeline, the corresponding torque and power changes are obtained when the detector moves at different speeds. Through the test platform system, the output power of the energy part at different speeds is collected, and the accuracy of the theoretical calculation is verified.

A Low Power Consumption Frequency Adaptation Mechanism Based on the Traffic and Implementation on NetFPGA

Lei Zhou,Lianghua Li,Xiaoju Liu,Xiaojun Wang 보안공학연구지원센터 2014 International Journal of Future Generation Communi Vol.7 No.6

Both in academic and industrial research, building a green energy-saving network has become a hot topic. Combined with hardware division and adaptive algorithm, this paper proposes an adaptive frequency control mechanism based on traffic to reduce power consumption. By calculating real-time traffic, the network device can adjust its operating frequency. On the premise of maintaining network performance, this mechanism could reduce the power consumption significantly. Besides, the adaptive frequency mechanism has been verified and realized in the NetFPGA Reference Router. Experimental data show that under different ranges of traffic loads and without affect its performance, the Router embedded this mechanism can reduce power consumption by more than 20%.

Optimisation of Readout Performance of Phase-Change Probe Memory in Terms of Capping Layer and Probe Tip

Lei Wang,C. David Wright,Mustafa. M. Aziz,Ci Hui Yang,Guo Wei Yang 대한금속·재료학회 2014 ELECTRONIC MATERIALS LETTERS Vol.10 No.6

The capping layer and the probe tip that serve as the protective layer and the recording tool, respectively, for phase-change probe memory play an important role on the writing performance of phase-change probe memory, thus receiving considerable attention. On the other hand, their influence on the readout performance of phasechange probe memory has rarely been reported before. A three-dimensional parametric study based on the Laplace equation was therefore conducted to investigate the effect of the capping layer and the probe tip on the resulting reading contrast for the two cases of reading a crystalline bit from an amorphous matrix and reading an amorphous bit from a crystalline matrix. The results indicated that a capping layer with a thickness of 2 nm and an electrical conductivity of 50 Ω−1m−1 is able to provide an appropriate reading contrast for both the cases, while satisfying the previous writing requirement, particularly with the assistance of a platinum silicide probe tip.