An Improved MITM Attack Against NTRU

Zhijian Xiong,Jinshuang Wang,Yanbo Wang,Tao Zhang,Liang Chen 보안공학연구지원센터 2012 International Journal of Security and Its Applicat Vol.6 No.2

Supercapacitors based on a nitrogen doped hierarchical porous carbon fabricated by self‑activation of biomass: excellent rate capability and cycle stability

Zhijian Zhang,Jingjing He,Xingchang Tang,Yuling Wang,Binbin Yang,Kunjie Wang,Deyi Zhang 한국탄소학회 2019 Carbon Letters Vol.29 No.6

Energy and environmental are always two major challenges for the sustainable development of the modern human being. For avoiding the serious environmental pollution caused in the fabrication process of porous carbon, a popular energy storage material, we reported a facile, green and activating agent free route hereby directly carbonizing a special biomass, Glebionis coronaria. A nitrogen doped hierarchical porous carbon with a specific surface area of up to 1007 m2 g−1 and a N doping content of up to 2.65 at.% was facilely fabricated by employing the above route. Benefiting from the peculiarly hierarchical porous morphology, enhanced wettability and improved conductivity, the obtained material exhibits superior capacitance performance, which capacitance reaches up to 205 F g−1 under two-electrode configuration, and no capacitance loss is observed after 5000 cycles. Meanwhile, the capacitance retention of the obtained material arrives up to 95.0% even under a high current density of 20 A g−1, illuminating its excellent rate capability. The fabricated nitrogen-doped hierarchical porous carbon with larger capacitance than commercial activated carbon, excellent rate capability and cycle stability is an ideal cost-efficient substitution of commercial activated carbon for supercapacitor application.

A Random Sequence Generation Method for Random Demodulation Based Compressive Sampling System

Li Wang,Yijiu Zhao,Zhijian Dai 보안공학연구지원센터(IJSIP) 2015 International Journal of Signal Processing, Image Vol.8 No.1

Random demodulation based compressive sampling technique is a novel approach that it can break through the Shannon sampling theorem for the sparse signal capturing. A major challenge in the random demodulation based sampling system is the random sequence generation. In this paper, we introduce an approach to generate the high-speed random sequence that meets the incoherence of compressive sampling. The proposed technique employs a field programmable gate array (FPGA). First, the random sequence is parallel stored in the memory of FPGA, and it is read out byte by byte using a low speed clock. Second, the low-speed byte sequence is converted to a high-speed bit sequence by a circuitry. This proposed approach can program the random sequence dynamically without making any change to the circuitry system. Experimental results indicate that, the random sequence generated by the proposed approach is feasible to sensing the signal, and the constructed system can compressively sample and reconstruct the sparse signal.

Compressive and Flexural Properties of Hemp Fiber Reinforced Concrete

Li, Zhijian,Wang, Lijing,Wang, Xungai The Korean Fiber Society 2004 Fibers and polymers Vol.5 No.3

The compressive and flexural properties of hemp fiber reinforced concretes (FRC) were examined in this paper. Natural hemp fiber was mixed using dry and wet mixing methods to fabricate the FRC. Mechanical properties of the FRC were investigated. The main factors affecting compressive and flexural properties of the FRC materials were evaluated with an orthogonal test design. Fiber content by weight has the largest effect. The method for casting hemp FRC has been optimised. Under the optimum conditions, compressive strength increased by 4 %, flexural strength increased by 9 %, flexural toughness increased by 144 %, and flexural toughness index increased by 214 %.

Supercapacitors based on a nitrogen doped hierarchical porous carbon fabricated by self-activation of biomass: excellent rate capability and cycle stability

Zhang Zhijian,He Jingjing,Tang Xingchang,Wang Yuling,Yang Binbin,Wang Kunjie,Zhang Deyi 한국탄소학회 2019 Carbon Letters Vol.29 No.6

Energy and environmental are always two major challenges for the sustainable development of the modern human being. For avoiding the serious environmental pollution caused in the fabrication process of porous carbon, a popular energy storage material, we reported a facile, green and activating agent free route hereby directly carbonizing a special biomass, Glebionis coronaria. A nitrogen doped hierarchical porous carbon with a specific surface area of up to 1007 m2 g−1 and a N doping content of up to 2.65 at.% was facilely fabricated by employing the above route. Benefiting from the peculiarly hierarchical porous morphology, enhanced wettability and improved conductivity, the obtained material exhibits superior capacitance performance, which capacitance reaches up to 205 F g−1 under two-electrode configuration, and no capacitance loss is observed after 5000 cycles. Meanwhile, the capacitance retention of the obtained material arrives up to 95.0% even under a high current density of 20 A g−1, illuminating its excellent rate capability. The fabricated nitrogen-doped hierarchical porous carbon with larger capacitance than commercial activated carbon, excellent rate capability and cycle stability is an ideal cost-efficient substitution of commercial activated carbon for supercapacitor application.

Experimental and Numerical Investigation on the Behaviour of Prestressed High Strength Concrete Pile-to-pile Cap ConnectionsExperimental and Numerical Investigation on the Behaviour of Prestressed High Strength Concrete Pile-to-pile Cap Connections

Zhijian Yang,Wenjin Wang 대한토목학회 2016 KSCE JOURNAL OF CIVIL ENGINEERING Vol.20 No.5

Six Prestressed High Strength Concrete (PHC) pile-to-pile cap connections were tested to evaluate their damage process and failure modes under low cyclic loading. The hysteretic behaviour, rotation angle, ductility and bearing capacity were observed and analyzed. In addition, the effect of connecting forms and cutting-off piles on seismic performance of pile-cap connections was considered and investigated. The experimental results showed that flexural bending failure occurred in all connections. There were two main failure modes. One was tensile rupturing of prestressed bars and headings, resulting in loss of bearing capacity of the connections. The other type was more severe damage due to anchor bar yield and appearance of plastic hinge. Moreover, bond-slip failure of anchor bars was not observed in the cap, and the length of anchor bars met requirements. The analysis indicated that the bearing capacity and energy dissipation capacity increased along with the rotation capacity of the pile connections. Nonlinear finite element models were established to analyze the mechanical properties of these connections using OpenSees. The load-displacement curves obtained from the numerical analysis agreed with the experimental results. The effects of various parameters on the behaviour of the connections were conducted based on the numerical model.

A new cable force identification method considering cable flexural rigidity

Wang, Long,Wu, Bo,Gao, Junyue,Shi, Kairong,Pan, Wenzhi,He, Zhuoyi,Ruan, Zhijian,Lin, Quanpan 국제구조공학회 2018 Structural Engineering and Mechanics, An Int'l Jou Vol.68 No.2

Cables are the main load-bearing members of prestressed structure and other tensegrity structures. Based on the static equilibrium principle, a new cable force identification method considering cable flexural rigidity is proposed. Its computational formula is derived and the strategy to solve its implicit formula is introduced as well. In order to improve the reliability and practicality of this method, the influence of the cable flexural rigidity on cable force identification accuracy is also investigated. Through cable force identification experiments, the relationships among certain parameters including jacking force, jacking displacement, initial cable force, and sectional area (flexural rigidity) are studied. The results show that the cable force calculated by the proposed method considering flexural rigidity is in good agreement with the finite element results and experimental results. The proposed method with high computational accuracy and resolution efficiency can avoid the influences of the boundary condition and the length of the cable on calculation accuracy and is proven to be conveniently applied to cable force identification in practice.

Phase transition enhanced thermoelectric performance for perovskites: The case of AgTaO3

Wang Zhijun,He Zhijian,Lei Chihou,Zou Daifeng,Liu Yunya 한국물리학회 2023 Current Applied Physics Vol.48 No.-

In general, perovskite materials, such as AgTaO3, can exhibit complex structural phase transitions when the temperature changes. Different phase structures may show distinct thermoelectric properties. However, the effects of phase transition on the thermoelectric performance of AgTaO3 have yet to be systematically investigated. Thus, in this work, the electronic structures and thermoelectric properties of the p-type AgTaO3 in various phase structures are investigated by utilizing first-principles calculations and semi-classical Boltzmann transport theory. The results show that the p-type AgTaO3 in the cubic phase shows a superior power factor because the cubic phase possesses a large Seebeck coefficient and intermediate electrical conductivity. The calculated thermoelectric performance is consistent with the predictions and explanations from the analyses of the electronic structures. When the p-type AgTaO3 is transformed from the tetragonal phase to the cubic phase, its power factor is tripled, suggesting that a suitable phase transition can improve the thermoelectric properties of perovskites.

b-Cyclodextrin-based poly(ionic liquids) membranes enable the efficient separation of the amino acids mixture

Wang Yu,Lianglei Liu,Fenfang Li,Zhijian Tan 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.103 No.-

As a kind of novel polyelectrolyte materials, poly(ionic liquids) (PILs) have excellent potentiality in theseparation of ampholytes suchlike amino acids. Herein, the b-cyclodextrin-based PILs had been synthesized,followed by blending with poly(vinylidene fluoride) (PVDF) to prepare poly(ionic liquid) membranes(PILMs). The Fourier transformed infrared (FT-IR) spectroscopy, 1H nuclear magnetic resonance(1H NMR), scanning electron microscope (SEM), thermal gravimetric analysis (TGA), mechanical strength,zeta potential, and pore size distribution were characterized for these membranes or their intermediates. These PILMs had been developed for the selection separation of the amino acids mixture of L-glutamicacid (L-Glu) and L-threonine (L-Thr). The factors influencing the separation result were investigated,including the solution pH of the amino acids mixture and the PVDF amount in PILMs. The maximumselectivity of 55% can be obtain by one-step separation under the optimal conditions. This separation processusing PILMs had the advantages of good selectivity, low operating pressure, larger water flux, andgood reusability, which had the potentiality in the separation of various amino acids mixtures.

Thermal Stress Model of Transversal Forced Air-Cooled Capacitor Banks for MWPower Converters

Zhijian Yin,Rui Wu,Morten Hygum,Yongheng Yang,Huai Wang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

Capacitor banks are key components in high power applications, the reliability of which affects the overall system lifetime. It is known that the thermal stress in each capacitor can affect the lifetime performance of the entire capacitor bank. In this paper, an analytical thermal model is presented to estimate the average capacitor thermal stress in a transversal forced air-cooled three-phase AC-filter capacitor bank for MW-level power converters. The proposed model calculates the thermal resistance of a capacitor bank considering power losses, geometry, cooling conditions and physical arrangement. With a conventional Foster thermal network, the hot-spot temperature and case temperature for each capacitor can be obtained. The experimental results on a full-scale three-phase filter capacitor bank consisting of 27 film sub-capacitors have demonstrated the effectiveness of this model.