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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.
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
Jun Jiang,Tianhao Xu,Yaping Li,Xiaodong Lei,Hui Zhang,D. G. Evans,Xiaoming Sun,Xue Duan 대한화학회 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 oC and activation process is essentially complete below 145 oC. 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 oC) afforded materials with optimum catalytic performance, since higher activation temperatures and/or longer activation times resulted in sintering of the silver particles.
New Arbitrated Quantum Signature Scheme without Entangled state
Jiang guanXiong,Zhang Jun 보안공학연구지원센터 2015 International Journal of Security and Its Applicat Vol.9 No.1
Arbitrated quantum signature (AQS) schemes use quantum cryptography to ensure their security, and the schemes provide that the signature receiver verifies the signature with the arbitrator’s assistance. Very recently, Gao and Choi found in some previous AQS schemes, the receiver, Bob can counterfeit the signer’s signature under known message. Additionally, the paper gives the security analysis of the AQS scheme, and results show that not only the receiver, but also the attacker can forge the signature in the AQS scheme. Furthermore, the signer can successfully disavow any message she ever signed. To conquer these shortcomings, this paper gives a new AQS scheme without quantum entangled state; it uses special quantum logic gate and new quantum one-time pads to ensure its security. Compares with other previous AQS schemes, the new scheme has following advantages: (1) the new scheme guarantees the receiver and the attacker cannot forge the signature; (2) Because the new scheme does not use quantum entangled states, so it can reduce the complexity of implementation and provides a higher efficiency in transmission; (3) The receiver, Bob has verified the signature’s integrity, so Alice cannot disavow her having signed message.
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.
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.
Jun Peng,Qian Wang,Jin Wang,Jun Yang,Taijun Jiang,Guangsheng Zeng 한국고분자학회 2022 Macromolecular Research Vol.30 No.11
Cardo containing phenoxy and -CF3 derivate diamine was synthesized, and further it was polymerized with 3,3',4,4'-biphenyl tetracarboxylic dianhydride to prepare polyetherimide containing Cardo group. The transmittance of the prepared polymer increased from 82% to 88% and the dielectric constant decreased from 2.91 to 2.83 with a slight decline in thermal and mechanical performance when -CF3 was introduced. The molecular simulation in terms of charge distribution, electric potential energy, chain stiffness and aggregation state revealed that -CF3 could restrain charge transfer and decrease the unit dipole moment and polarization for its larger volume. The optical and dielectric performance was significantly enhanced, but the thermal and mechanical performance decreased slightly when the -CF3 group was introduced. The glass transition temperature of the polymer declined from 329℃ to 311℃. The investigation conducted in this paper can offer valuable reference to the optimization and development of synthesis and comprehensive performance of polyimide.
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.