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( Liu Bin ),( Ning Ning Zhang ),( Chao Zhao ),( Bai Xue Lin ),( Lian Hui Xie ),( Yi Fan Huang ) 한국미생물 · 생명공학회 2012 Journal of microbiology and biotechnology Vol.22 No.10
A xylanase-producing thermophilic strain, Geobacillus sp. TC-W7, was isolated from a hot spring in Yongtai (Fuzhou, China). Subsequently, the xylanase gene that encoded 407 amino acids was cloned and expressed. The recombinant xylanase was purified by GST affinity chromatography and exhibited maximum activity at 75℃ and a pH of 8.2. The enzyme was active up to 95℃ and showed activity over a wide pH range of 5.2 to 10.2. Additionally, the recombinant xylanase showed high thermostability and pH stability. More than 85% of the enzyme`s activity was retained after incubation at 70℃ for 90 min at a pH of 8.2. The activity of the recombinant xylanase was enhanced by treatment with 10 mM enzyme inhibitors (DDT, Tween-20, 2-Me, or TritonX-100) and was inhibited by EDTA or PMSF. Its functionality was stable in the presence of Li+, Na+, and K+, but inhibited by Hg2+, Ni2+, Co2+, Cu2+, Zn2+, Pb2+, Fe3+, and Al3+. The functionality of the crude xylanase had similar properties to the recombinant xylanase except for when it was treated with Al2+ or Fe2+. The enzyme might be a promising candidate for various industrial applications such as the biofuel, food, and paper and pulp industries.
Spatial spectrum approach for pilot spoofing attack detection in MIMO systems
Ning, Lina,Li, Bin,Wang, Xiang,Liu, Xiaoming,Zhao, Chenglin Electronics and Telecommunications Research Instit 2021 ETRI Journal Vol.43 No.5
In this study, a spatial spectrum method is proposed to cope with the pilot spoofing attack (PSA) problem by exploiting the of uplink-downlink channel reciprocity in time-division-duplex multiple-input multiple-output systems. First, the spoofing attack in the uplink stage is detected by a threshold derived from the predefined false alarm based on the estimated spatial spectrum. When the PSA occurs, the transmitter (That is Alice) can detect either one or two spatial spectrum peaks. Then, the legitimate user (That is Bob) and Eve are recognized in the downlink stage via the channel reciprocity property based on the difference between the spatial spectra if PSA occurs. This way, the presence of Eve and the direction of arrival of Eve and Bob can be identified at the transmitter end. Because noise is suppressed by a spatial spectrum, the detection performance is reliable even for low signal-noise ratios and a short training length. Consequently, Bob can use beamforming to transmit secure information during the data transmission stage. Theoretical analysis and numerical simulations are performed to evaluate the performance of the proposed scheme compared with conventional methods.
Analysis of Cracking Development and Mechanical Characteristics of High-Filled Cut-and-Cover Tunnel
Bin Zhuo,Feiyang Wang,Yong Fang,Yan Chen,Guixia Ning 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.8
The cut-and-cover tunnel (CCT) construction scheme has led to the popularity of high-filled cut-and-cover tunnel (HFCCT). HFCCT possesses a backfilling height of 30 − 50 m. However, such a high soil column produces a large force on the structure and the structure is prone to crack, causing structural damage and difficulty in normal use. In order to provide a reference for the structural safety assessment of HFCCT, we conducted a similarity model test to study the variation law of the development of crack, displacement, and internal force of HFCCT with a coefficient of λ (the ratio of the backfilling height to the height of the cut-and-cover tunnel). In the test, a 1:20 similar scale CCT model with slope angle 70° and groove width ratio 1 was built using data from the HFCCT on the Lanyu Line. The backfilling process on site was simulated in a simulation box (360 cm long, 120 cm wide and 209 cm high). A numerical model was also built using PFC2D to verify the accuracy of the model test and further explain the crack formation mechanism of the HFCCT from a microscopic perspective. The results show that with the increase of the coefficient of λ, the bearing stage of the CCT can be roughly divided into three stages: steady growth stage, rapid growth stage, and accelerated growth stage. Furthermore, the development of cracks is closely related to the displacement and internal force of the CCT. The larger the displacement of the CCT, the greater the instability of the structure and the larger the ratio of the bending moment to the internal force, which causes the crack to develop faster.
Dynamic Task Scheduling Via Policy Iteration Scheduling Approach for Cloud Computing
( Bin Hu ),( Ning Xie ),( Tingting Zhao ),( Xiaotong Zhang ) 한국인터넷정보학회 2017 KSII Transactions on Internet and Information Syst Vol.11 No.3
Dynamic task scheduling is one of the most popular research topics in the cloud computing field. The cloud scheduler dynamically provides VM resources to variable cloud tasks with different scheduling strategies in cloud computing. In this study, we utilized a valid model to describe the dynamic changes of both computing facilities (such as hardware updating) and request task queuing. We built a novel approach called Policy Iteration Scheduling (PIS) to globally optimize the independent task scheduling scheme and minimize the total execution time of priority tasks. We performed experiments with randomly generated cloud task sets and varied the performance of VM resources using Poisson distributions. The results show that PIS outperforms other popular schedulers in a typical cloud computing environment.
ARCHITECTURE OF FLOWER-LIKE rGO/CNTs-LOADED CuxO NANOPARTICLES AND ITS PHOTOCATALYTIC PROPERTIES
BIN ZENG,XIAOHUA CHEN,XUTAO NING,CHUANSHENG CHEN,HUI LONG 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.5
Novel flower-like composite architecture was successfully synthesized by spray drying and post-calcinating method for the first time. Scanning electron microscopy and transmission electron microscopy observations confirmed that reduced graphene oxides/carbon nanotubes hybrid (rGO/CNTs) formed a flower-like micrometer structure and Cu2O, CuO (CuxO, x = 1 or 2) nanoparticles were decorated inside them. The photocatalytic properties were further investigated by evaluating the photodegradation of a pollutant methyl orange (MO). The experimental results indicated that this novel architecture enhanced photocatalytic performance with 96.2% decomposition of MO after 25 min in the presence of H2O2 under visible light irradiation, which was much higher than that of CuxO powders (33.2%). This could be attributed to the more efficient adsorption of MO molecules on flower-like rGO/CNTs and provide a high concentration of MO near to the CuxO nanoparticles, thus promoting the photocatalytic degradation process.
Bin Chen,Ning Zhang 보안공학연구지원센터 2016 International Journal of Grid and Distributed Comp Vol.9 No.1
Information technology has entered a big-data era. Large-scale data is becoming the basic factors of production and it would affect the corporate social responsibility disclosure deeply, the use of big data has become the key factor to improve the competitiveness of enterprises. Through this empirical analysis, we can draw the following conclusions: corporate social responsibility is mainly composed of economic responsibility, legal responsibility, ethical responsibility and spontaneous responsibility. And CSR will have positive effect on organizational performance. All of these indicate that prompting enterprises staff to fulfill corporate social responsibility is helpful to improve the organizational performance.
Bin Li,Ning Sun,Hao Wang,Dandan Hu,Zhihui Zeng 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.9
This paper discusses the power coupling problem of the traditional virtual synchronous generator (VSG) control strategy in medium and low-voltage microgrids, analyzes the cause of power coupling, and discusses the necessity for decoupling. In addition, a power decoupling control strategy based on an adaptive diagonal matrix compensation matrix is proposed. By compensating for the coupling component, the output power of the VSG is completely decoupled. To cope with the operating characteristics of frequent load switching on the grid side of a microgrid, the proposed strategy tracks variations in the static operating point of the VSG and automatically adjusts the compensation component. Simultaneously, the stability of the VSG is analyzed, using the transient instability criterion of the power system, to ensure decoupling. Finally, the effectiveness of the proposed control strategy is verified by simulation and experimental results.