A study on the new high strength casting Al-Cn alloy by heat treatment and structure property

Jiang Jun,HyunJun Lee,SunChul Huh,WonJo Park 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.10

Aging and solid-solution are main methods to strengthen metal, and their optimal strengthening temperature and time are more and more drew attention to study. Al-Cu alloys are one kind of typical precipitation hardening alloy, and high strength casting Al-Cu alloy has been widely used in industry. In this study the authors use heat treatment and aging to strengthen the alloy, and then the analysis techniques such as transmission electron microscopy (TEM), scanning electron microscopy (SEM), optical metallographic examination(OM), metallographic analysis, fracture analysis and electron diffraction were employed in this dissertation.

The Influence of Precipitated Phase in Al-4%Cu Alloy under High Magnetic Field

Jiang Jun,HyunJun Lee,Qi Min,WonJo Park 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11

Nonferrous metals have a very important position in industry. At present, parts of shipbuilding, automobile, and aircraft etc. are designed and manufactured accurately, simultaneity need light-weight and high-strength. Aluminum copper alloys are one kind of typical precipitation hardening alloy which has been widely used. It is interesting to investigate transformation behavior of precipitated phase in such kind of alloys under high magnetic field. Transformation of materials under high magnetic field is many different compared with conventional condition. The author prepared the Al-4%Cu alloy.

Influence of the precipitated phases in Al-4%Cu alloys processed in the high magnetic field and cryogenic treatment

Jiang Jun,Qi Min,Won-Jo Park 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

Transformation of materials under high magnetic field is much different compared with conventional condition. There is big significant in materials science investigating transformation behavior of materials under high magnetic field. Aluminium copper alloys are one kind of typical precipitation hardening alloy which has been widely used in industry. It is interesting to investigate transformation behavior of such kind of alloys under high magnetic field. The author prepared the Al-4%Cu alloy using crucible electrical resistance furnace in order to further the research of the Al-Cu binary alloy. The analysis techniques such as optical microscopy (OM), Vickers micro-hardness, and X-ray diffraction and transmission electron microscopy (TEM) were employed in this dissertation. Firstly the Al-4%Cu alloys which annealed at 180 ℃ are briefly studies. Then the precipitating behavior of second phases in specimens that aged with and without high magnetic field and through cryogenic treatment were analyzed and discussed mainly based on the comparison of experimental results of Vickers micro-hardness testing and XRD analysis respectively.

A Deep Investigation of the Thermal Decomposition Process of Supported Silver Catalysts

Jiang, Jun,Xu, Tianhao,Li, Yaping,Lei, Xiaodong,Zhang, Hui,Evans, D.G.,Sun, Xiaoming,Duan, Xue Korean Chemical Society 2014 Bulletin of the Korean Chemical Society Vol.35 No.6

A deep understanding of the metallic silver catalysts formation process on oxide support and the formation mechanism is of great scientific and practical meaning for exploring better catalyst preparing procedures. Herein the thermal decomposition process of supported silver catalyst with silver oxalate as the silver precursor in the presence of ethylenediamine and ethanolamine is carefully investigated by employing a variety of characterization techniques including thermal analysis, in situ diffuse reflectance infrared Fourier transform spectroscopy, scanning electron microscopy, and X-ray diffraction. The formation mechanism of supported silver particles was revealed. Results showed that formation of metallic silver begins at about $100^{\circ}C$ and activation process is essentially complete below $145^{\circ}C$. Formation of silver was accompanied by decomposition of oxalate group and removal of organic amines. Catalytic performance tests using the epoxidation of ethylene as a probe reaction showed that rapid activation (for 5 minutes) at a relatively low temperature ($170^{\circ}C$) afforded materials with optimum catalytic performance, since higher activation temperatures and/or longer activation times resulted in sintering of the silver particles.

The XRCC3 Thr241Met Polymorphism Influences Glioma Risk - A Meta-analysis

Jiang, Jun,Quan, Xun-Feng,Zhang, Li,Wang, Yi-Chun Asian Pacific Journal of Cancer Prevention 2013 Asian Pacific journal of cancer prevention Vol.14 No.5

Background: Findings from previous published studies regarding the association of the XRCC3 Thr241Met polymorphism with glioma susceptibility have often been conflicting. Therefore, a meta-analysis including all available publications was carried out to make a more precise estimation of the potential relationship. Methods: By searching the electronic databases of Pubmed and Embase (up to April 1st, 2013), a total of nine case-control studies with 3,752 cases and 4,849 controls could be identified for inclusion in the current meta-analysis. Odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to assess the strength of the association. Results: This meta-analysis showed the XRCC3 Thr241Met polymorphism to be significantly associated with decreased glioma risk in the allelic model (Met allele vs. Thr allele: OR= 0.708, 95%CI= 0.631-0.795). Moreover, we also observed a statistically significant association between the XRCC3 Thr241Met polymorphism and reduced glioma risk in analyses stratified by ethnicity (Asian) and source of controls (hospital based) in the allelic model. Conclusions: Current evidence suggests that the XRCC3 Thr241Met polymorphism may be a risk factor for glioma development, especially in Asians.

Temporary formation of highly conducting domain walls for non-destructive read-out of ferroelectric domain-wall resistance switching memories

Jiang, Jun,Bai, Zi Long,Chen, Zhi Hui,He, Long,Zhang, David Wei,Zhang, Qing Hua,Shi, Jin An,Park, Min Hyuk,Scott, James F.,Hwang, Cheol Seong,Jiang, An Quan Nature Publishing Group, a division of Macmillan P 2018 NATURE MATERIALS Vol.17 No.1

Erasable conductive domain walls in insulating ferroelectric thin films can be used for non-destructive electrical read-out of the polarization states in ferroelectric memories. Still, the domain-wall currents extracted by these devices have not yet reached the intensity and stability required to drive read-out circuits operating at high speeds. This study demonstrated non-destructive read-out of digital data stored using specific domain-wall configurations in epitaxial BiFeO<SUB>3</SUB> thin films formed in mesa-geometry structures. Partially switched domains, which enable the formation of conductive walls during the read operation, spontaneously retract when the read voltage is removed, reducing the accumulation of mobile defects at the domain walls and potentially improving the device stability. Three-terminal memory devices produced 14 nA read currents at an operating voltage of 5 V, and operated up to T = 85 °C. The gap length can also be smaller than the film thickness, allowing the realization of ferroelectric memories with device dimensions far below 100 nm.

Decision models of Multi Periods Closed Loop Supply Chain with Remanufacturing under Centralized and Decentralized Decision Making

JiangJun Yuan 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.10

A Study on the Algorithm of Supply Chain Protection Based on Zero-sequence Compensation

JiangJun Yuan 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.2

To deal with the faulted line selection in the single-phase to ground faults caused by neutral non-effective grounding in the distribution network, a new method by using zero-sequence admittance is proposed in this paper. Compensation admittance, which amplifies the difference in zero-sequence admittance between the faulted line and the unfaulted line, is convenient for the formation of the criteria for value setting in engineering. To eliminate the blind zone, combining the criterion of the susceptance error in the compensated admittance with the phase angle criterion helps form a new algorithm to identify the single-phase to ground faults in the neutral non-effectively grounded system. Results of simulation tests show that the algorithm has nothing to do with the network structure and parameters, fault conditions and fault resistance, significantly escalating the successful selection of the faulted line.

Risk Aversion Coordination Simulation Model for Supply Chain

Yuan JiangJun 보안공학연구지원센터 2015 International Journal of u- and e- Service, Scienc Vol.8 No.6

Facing the complex and changeful market environment, members of the enterprise in supply and demand network more consider seeking to build partnerships, with a specialization in a larger scope; effectively reduce all kinds of business cost of the enterprise, fully realized system scale effect. First discussed the basic characteristics of the network of supply and demand and enterprise, using the game theory analysis method and the least squares curve fitting of ideas, constructing a dynamic game model of the cooperation of supply and demand network enterprise dynamic evolution; And then analyzed the results of cooperative game, get the optimal expected revenue function and cooperation profit coefficient which is the important factor of enterprise dynamic cooperation choice to influence members of supply and demand network; Finally, considered a two layers of supply and demand system consisting of a risk averse retailer and risk aversion of the manufacturers, retailers to develop the optimal wholesale price, manufacturers to determine the optimal distribution, constructed based on revenue sharing costs shared network coordination model of supply and demand. Simulation results show that when the supply and demand system of risk aversion coefficient is higher than the risk aversion coefficient of manufacturers and retailers, the revenue sharing cost sharing contract system can be improved significantly, even perfect coordination.

Analysis of Transient Magnetic Force on End‑Winding in the Inverter‑Fed Induction Machine

Liezheng Tang,Jiangjun Ruan,Hengyu Ding,Tao Huang,Hailong Liu 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.1

The increasing harmonics caused by inverter supply have an adverse impact on the end-winding vibration of the induction machine in accelerating failure and adding noise. Therefore, this paper puts forward an approach for end-winding magnetic force calculation in the inverter-fed induction machine. The 2D feld–circuit–motion coupling analysis is used to calculate the stator currents in an induction machine, which are taken as loads in 3D transient magnetic analysis to obtain magnetic force on the end-windings. A three-phase squirrel-cage induction machine was designed and an experiment was carried out on the test motor to validate the proposed model. The simulated stator current, magnetic fux density and magnetic force agree well with both the theoretical analysis and measured results. Finally, a 3-D transient structural simulation was performed to further analyze the end-winding vibration. However, there is some diference of end-winding vibration acceleration between the simulation and experiment in harmonic components. The above deviation is probably attributed to the structure simplifcation of the induction machine. Thus, the developed simulation model can calculate the magnetic force on end-winding with reasonable accuracy, but it is advisable to perform an experimental study to fully analyze the vibration characteristics of end-winding.