Structure and Thermal-enhanced Magnetic Properties of Mn4C Melt-spun Ribbons with Varied Stoichiometry

Ting-Ting Qi,Ping-Zhan Si,Fang Cheng,Zhi-Rui Wang,Hong-Liang Ge,Qiong Wu,Jihoon Park,Chul-Jin Choi 한국자기학회 2023 Journal of Magnetics Vol.28 No.1

Cubic perovskite-type Mn4C is difficult to prepare for its metastable characteristics. In this work, we have obtained high-purity Mn4C successfully by using melt-spinning method. The effects of stoichiometry on the structure and magnetic properties of the samples were studied systematically. We found that x = -0.1 is the optimum composition for the formation of the cubic perovskite phase in Mn4+xC during rapid quenching. Most Mn4+xC melt-spun ribbons with x other than -0.1 are composed of Mn23C6, α-Mn, and Mn4C, while the fraction of different phase in Mn4+xC ribbons varies with x. The Curie temperature of Mn4+xC ribbons increases slightly with decreasing x, which may affect the lattice parameters of cubic Mn4C and thus the Mn-Mn exchange interactions. The magnetization of Mn4+xC (x = -0.1 and 0) increases with increasing temperature in high-temperature region while the onset temperature for such behavior is dependent on the fraction of Mn4C in the samples.

Tradeoff between the Output Voltage Deviation and Recovery Time of Boost Converters

Ge, Junjie,Yuan, Liqiang,Zhao, Zhengming,Lu, Ting,He, Fanbo,Feng, Gaohui The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

The time-optimal control for boost converters can achieve the minimum recovery time. However, their output voltage deviation is quite large. Since the minimum output voltage deviation and minimum recovery time cannot be obtained at the same time, a novel energy control is proposed to achieve a superior tradeoff between them in this paper. The peak value of the inductor current can be decreased as well. Its control parameter is easy to choose. When compared with the conventional control methods, the proposed control shows a better dynamic performance. Experimental results, which are in agreement with the theoretical analysis, are provided to verify the proposed control method.

Evaluating genetic diversity and identifying priority conservation for seven Tibetan pig populations in China based on the mtDNA D-loop

Ge Qianyun,Gao Caixia,Cai Yuan,Jiao Ting,Quan Jinqiang,Guo Yongbo,Zheng Wangshan,Zhao Shengguo 아세아·태평양축산학회 2020 Animal Bioscience Vol.33 No.12

Objective: Tibetan pigs, an excellent species unique to China, face serious threats, which in turn affects the development and utilization of the outstanding advantages of plateau hypoxia adaptability and reduces their genetic diversity. Therefore, a discussion of measures to conserve this genetic resource is necessary. The method, based on genetic diversity, genetic divergence and total genetic contribution rate of population, reflects the priority conservation order and varies depending on the three different purposes of conservation. Methods: We analyzed mitochondrial DNA control region (D-loop) variation in 1,201 individuals from nine Tibetan pig populations across five provinces and downloaded 564 mtDNA D-loop sequences from three indigenous pig breeds in Qinghai, Sichuan, and Yunnan Provinces distributed near the Tibetan pigs. Results: We analyzed three different aspects: Changdu Tibetan pigs have the highest genetic diversity, and from the perspective of genetic diversity, the priority conservation is Changdu Tibetan pigs. Hezuo Tibetan pigs have the highest genetic contribution, so the priority conservation is Hezuo Tibetan pigs in the genetic contribution aspect. Rkaze Tibetan pigs were severely affected by indigenous pig breeds, so if considering from the perspective of introgression, the priority conservation is Rkaze Tibetan pigs. Conclusion: This study evaluated genetic diversity and comprehensively assessed conservation priority from three different aspects in nine Tibetan pig populations.

Observer-based H∞ Control for Synchronization in Delayed Neural Networks Under Multiple Disturbances

Ting Wang,Jifeng Ge,Tao Li,Xin Chen,Shumin Fei 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.12

In this paper, the problem on master-slave synchronization is investigated for a class of delayed neural networks (DNNs) subject to multiple variable disturbances, where the synchronization can be widely utilized in many engineering fields such as teleoperation control, secure communication, and so on. Initially, the unknown disturbances are assumed to be generated by two external systems, in which the additional ones are required to belong to the space of L2[0,+∞). Then based on disturbance-observer-based-control method, H∞ control technique, and composite controller, a sufficient condition on designing the observer gains and controller ones are established to ensure that the overall closed-loop system is asymptotically stable with H∞ control performance. Furthermore, by using matrix transformation technique, the derived condition is converted into the linear matrix inequality (LMI)forms, which can be easily checked and present much less conservatism. Finally, some simulations and comparisons in an example are given to illustrate the effectiveness of our control methods.

The domestication event of the Tibetan pig revealed to be in the upstream region of the Yellow River based on the mtDNA D-loop

Ge, Qianyun,Gao, Caixia,Cai, Yuan,Jiao, Ting,Quan, Jinqiang,Guo, Yongbo,Zheng, Wangshan,Zhao, Shengguo Asian Australasian Association of Animal Productio 2020 Animal Bioscience Vol.33 No.4

Objective: Evidence from previous reports indicates that pig domestication in East Asia mainly occurred in the Mekong region and the middle and downstream regions of the Yangtze River. Further research identified two new origin centers for domestic pigs in the Tibetan Plateau and the islands of Southeast Asia. However, due to the small sample size of Tibetan pigs, details of the origin and spread of Tibetan pigs has not yet been established. Methods: We analyzed mitochondrial DNA control region (D-loop) variation in 1,201 individuals from nine Tibetan pig populations across five provinces. Comprehensive Tibetan pig samples were taken to perform the most detailed analysis of Tibetan pigs to date. Results: The result indicate that Rkaze pigs had the lowest level of diversity, while Changdu pigs had the highest diversity. Interestingly, these two populations were both in the Tibetan Plateau area. If we calculate diversity in terms of each province, the Tibetan Plateau area had the lowest diversity, while the Chinese province of Gansu had the highest diversity. Diversity gradient analysis of major haplotypes suggested three domestication centers of Tibetan pigs in the Tibetan Plateau and the Chinese provinces of Gansu and Yunnan. Conclusion: We found two new domestication centers for Tibetan pigs. One is in the Chinese province of Gansu, which lies in the upstream region of the Yellow River, and the other is in the Chinese province of Yunnan.

Tradeoff between the Output Voltage Deviation and Recovery Time of Boost Converters

Junjie Ge,Liqiang Yuan,Zhengming Zhao,Ting Lu,Fanbo He,Gaohui Feng 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.2

The time-optimal control for boost converters can achieve the minimum recovery time. However, their output voltage deviation is quite large. Since the minimum output voltage deviation and minimum recovery time cannot be obtained at the same time, a novel energy control is proposed to achieve a superior tradeoff between them in this paper. The peak value of the inductor current can be decreased as well. Its control parameter is easy to choose. When compared with the conventional control methods, the proposed control shows a better dynamic performance. Experimental results, which are in agreement with the theoretical analysis, are provided to verify the proposed control method.

Mechanism on suppression in vortex-induced vibration of bridge deck with long projecting slab with countermeasures

Zhiyong Zhou,Ting Yang,Quanshun Ding,Yaojun Ge 한국풍공학회 2015 Wind and Structures, An International Journal (WAS Vol.20 No.5

The wind tunnel test of large-scale sectional model and computational fluid dynamics (CFD) are employed for the purpose of studying the aerodynamic appendices and mechanism on suppression for the vortex-induced vibration (VIV). This paper takes the HongKong-Zhuhai-Macao Bridge as an example to conduct the wind tunnel test of large-scale sectional model. The results of wind tunnel test show that it is the crash barrier that induces the vertical VIV. CFD numerical simulation results show that the distance between the curb and crash barrier is not long enough to accelerate the flow velocity between them, resulting in an approximate stagnation region forming behind those two, where the continuous vortex-shedding occurs, giving rise to the vertical VIV in the end. According to the above, 3 types of wind fairing (trapezoidal, airfoil and smaller airfoil) are proposed to accelerate the flow velocity between the crash barrier and curb in order to avoid the continuous vortex-shedding. Both of the CFD numerical simulation and the velocity field measurement show that the flow velocity of all the measuring points in case of the section with airfoil wind fairing, can be increased greatly compared to the results of original section, and the energy is reduced considerably at the natural frequency, indicating that the wind fairing do accelerate the flow velocity behind the crash barrier. Wind tunnel tests in case of the sections with three different countermeasures mentioned above are conducted and the results compared with the original section show that all the three different countermeasures can be used to control VIV to varying degrees.

Security Analysis of the Khudra Lightweight Cryptosystem in the Vehicular Ad-hoc Networks

( Wei Li ),( Chenyu Ge ),( Dawu Gu ),( Linfeng Liao ),( Zhiyong Gao ),( Xiujin Shi ),( Ting Lu ),( Ya Liu ),( Zhiqiang Liu ) 한국인터넷정보학회 2018 KSII Transactions on Internet and Information Syst Vol.12 No.7

With the enlargement of wireless technology, vehicular ad-hoc networks (VANETs) are rising as a hopeful way to realize smart cities and address a lot of vital transportation problems such as road security, convenience, and efficiency. To achieve data confidentiality, integrity and authentication applying lightweight cryptosystems is widely recognized as a rather efficient approach for the VANETs. The Khudra cipher is such a lightweight cryptosystem with a typical Generalized Feistel Network, and supports 80-bit secret key. Up to now, little research of fault analysis has been devoted to attacking Khudra. On the basis of the single nibble-oriented fault model, we propose a differential fault analysis on Khudra. The attack can recover its 80-bit secret key by introducing only 2 faults. The results in this study will provides vital references for the security evaluations of other lightweight ciphers in the VANETs.

Mechanism on suppression in vortex-induced vibration of bridge deck with long projecting slab with countermeasures

Zhou, Zhiyong,Yang, Ting,Ding, Quanshun,Ge, Yaojun Techno-Press 2015 Wind and Structures, An International Journal (WAS Vol.20 No.5

The wind tunnel test of large-scale sectional model and computational fluid dynamics (CFD) are employed for the purpose of studying the aerodynamic appendices and mechanism on suppression for the vortex-induced vibration (VIV). This paper takes the HongKong-Zhuhai-Macao Bridge as an example to conduct the wind tunnel test of large-scale sectional model. The results of wind tunnel test show that it is the crash barrier that induces the vertical VIV. CFD numerical simulation results show that the distance between the curb and crash barrier is not long enough to accelerate the flow velocity between them, resulting in an approximate stagnation region forming behind those two, where the continuous vortex-shedding occurs, giving rise to the vertical VIV in the end. According to the above, 3 types of wind fairing (trapezoidal, airfoil and smaller airfoil) are proposed to accelerate the flow velocity between the crash barrier and curb in order to avoid the continuous vortex-shedding. Both of the CFD numerical simulation and the velocity field measurement show that the flow velocity of all the measuring points in case of the section with airfoil wind fairing, can be increased greatly compared to the results of original section, and the energy is reduced considerably at the natural frequency, indicating that the wind fairing do accelerate the flow velocity behind the crash barrier. Wind tunnel tests in case of the sections with three different countermeasures mentioned above are conducted and the results compared with the original section show that all the three different countermeasures can be used to control VIV to varying degrees.

A novel and efficient procedure for the preparation of 4,40-bis(chloromethyl)biphenyl by chloromethylation of biphenyl catalyzed by PEG1000-DAIL under homogeneous catalysis in aqueous media

Yu Lin Hu,Qiang Ge,Peng Cheng Wang,Ting Ting Lu,Ming Lu 한국공업화학회 2010 Journal of Industrial and Engineering Chemistry Vol.16 No.4

As described in this article, 4,40-bis(chloromethyl)biphenyl was obtained in 85% excellent yield by chloromethylation of biphenyl catalyzed by the recyclable temperature-dependant phase-separation system that comprised the dicationic acidic ionic liquid PEG1000-DAIL and methylcyclohexane under homogeneous catalysis in aqueous media. Compared to other synthetic methods, the novel method not only enhanced the yield, but also made the operating units easy workup. The mechanism of chloromethylation reaction and the process of catalysis in the thermoregulated ionic liquid bi-phase system were proposed.