Degrees of Freedom of Two-Cluster MIMO Multiway Relay Interference Channels Using Blind Interference Neutralization

( Bowei Zhang ),( Wenjiang Feng ),( Tingting Dong ),( Yina Deng ) 한국인터넷정보학회 2016 KSII Transactions on Internet and Information Syst Vol.10 No.1

In this paper, we investigate the degrees of freedom (DoF) of a two-cluster multiple-input multiple-output (MIMO) multiway relay interference channel (mRIC), where there are two relays and two users per cluster. In this channel, users within the same cluster exchange messages among themselves with the help of two relays. We first obtain the DoF upper bound of the considered MIMO mRIC based on cut-set bound. Then, we propose a novel transmission strategy, blind interference neutralization (BIN), to approach the DoF upper bound. This new method utilizes the overheard information at two relays and focuses on the beamforming matrix designs at two relays so that the channel state information (CSI) at users is not required. Through theoretical analysis and numerical simulations, we show that the DoF upper bound can be obtained by using the BIN scheme. From simulation results, we show that the proposed BIN scheme can provide significant performance gain over the conventional time division multiple access (TDMA) scheme in terms of DoF. In addition, we show that the BIN scheme is a superior approach to the existing signal space alignment (SSA) schemes for the considered mRIC.

The crucial role of intermolecular π-π interactions in A-D-A-type electron acceptors and their effective modulation

Gao, Bowei,Yao, Huifeng,Jang, Bomee,Zhu, Jie,Yu, Runnan,Cui, Yong,Wang, Fenghao,Hou, Junxian,Woo, Han Young,Hou, Jianhui The Royal Society of Chemistry 2018 Journal of Materials Chemistry A Vol.6 No.6

<P>Here, the crucial role of intermolecular π-π interactions in A-D-A-type acceptors is examined and a simple yet effective modulation method is presented. By side chain manipulation, two small molecule acceptors, IDT-C6 and IDT-PhC6, are designed and synthesized with different crystalline morphologies. Since <I>n</I>-hexyl side chains have less steric hindrance than hexylphenyl side chains, IDT-C6 exhibits enhanced intermolecular π-π interactions relative to IDT-PhC6. Benefiting from the improved charge transport properties of the IDT-C6-based device, a high PCE of 12.5% is recorded, whereas those of the IDT-PhC6-based device delivers a moderate PCE of just 5.6%.</P>

Simultaneous isolation of cellulose and lignin from wheat straw and catalytic conversion to valuable chemical products

Yu Bowei,Fan Guozhi,Zhao Sijiu,Lu Yuchan,He Qiao,Cheng Qunpeng,Yan Juntao,Chai Bo,Song Guangsen 한국응용생명화학회 2021 Applied Biological Chemistry (Appl Biol Chem) Vol.64 No.1

Convertible cellulose and lignin were simultaneously isolated from wheat straw using a two-stage process via simply varying temperature and H2SO4 concentration. At the first-stage, cellulose was obtained by pretreating wheat straw at lower temperature and acid concentration using an organosolv process. The purity, yield and recovery rate of cellulose reached 86.8 wt%, 55.2 and 92.8% at 150 °C with 1 wt% H2SO4. At the second stage, the residual liquid was further treated at higher temperature and acid concentration, giving 17.4% lignin yield with 86.6% recovery rate and 93.2 wt% purity at 180 °C with 1.5 wt% H2SO4. The conversion of the as-isolated cellulose and lignin into chemicals was further investigated. The total yield of 5-hydroxymethylfurfural and glucose derived from wheat straw cellulose reached 82.5%, and 18.3% yield of monophenolic compounds from lignin were obtained, respectively. These results indicated that the two-stage process was effective for obtaining high-quality cellulose and lignin from wheat straw. Both of them displayed excellent convertible property.

`연행록(燕行錄)` 및 관련 문헌의 `진실성(眞實性)` 문제 초탐(初探)

장백위 ( Zhang Bowei ) 성균관대학교 대동문화연구원 2017 大東文化硏究 Vol.97 No.-

`연행록` 및 관련 문헌의 사료적 가치는 의심할 여지없이 방대하면서도 귀중한 존재 의의를 지닌다. 연행 문헌에 관한 정리와 연구는 금세기 이래 동아시아 지역에서 주요 관심사가 되어 왔다. 그러나 우리는 이 문헌이 귀중한 점을 중시함과 동시에, 이런 종류의 문헌이 지닌 모종의 특징을 파악할 필요성과 기록 내용의 `진실성`에 대한 충분한 경각심이 요구됨에도 불구하고, 그것의 결핍으로 인해 오류 생산을 초래하고 있는 실정이다. 본고는 연행 문헌의 `失實`을 전후의 표절, 관찰 태도, `문화전쟁`의 장으로 나누고 각각의 상황에서 야기되는 실례를 중심으로 논의를 전개 하였다. 연행 문헌이 지닌 특징들에 대한 충분한 인지가 선행되어야 비로소 그 의미를 오류 없이 해독할 수 있을 것이다. In term of its value as historical records, "Travel Account to Beijing" and relevant documents are a huge and precious database for East Asian studies. From the beginning of the 21st century, the editing and research of "Travel Account to Beijing" more and more become a scholarly hotspot in East Asian community. Although scholars pay much attention to its important historical values, they seem to have grasped characteristics of such kind of records correctly, so are lack of vigilance on the "authenticity" of these data, which leads to some errors. This paper argues that the "inaccuracies" of "Travel Account to Beijing" were caused by plagiarism of later envoys to former records, reading attitude, and the context of "literary contest" between Korean envoys and Chinese official-scholars. Contemporary scholars should be aware of the characteristics of "Travel Account to Beijing" fully, then they could grasp the meanings the these data correctly.

明淸之際書籍環流與朝鮮女性詩文

張伯偉(Zhang Bowei) 고려대학교 한자한문연구소 2015 동아한학연구 Vol.- No.10

Selective Synthesis of N,N-Bis(3-dimethylaminopropyl)amine over Pd/γ-Al2O3

Chenhui Lin,Bowei Wang,Haotian Guo,Ligong Chen,Xilong Yan 대한화학회 2018 Bulletin of the Korean Chemical Society Vol.39 No.3

The synthesis of N,N-bis(3-dimethylaminopropyl)amine (BPA) from 3-(dimethylamino)-propionitrile (PN) and 3-(N,N-dimethylamino)propylamine (PA) over Pd/γ-Al2O3 in autoclaves was investigated. A series of Pd catalysts were prepared by different methods and characterized by XRD, TEM, and N2 adsorption–desorption. It was found that their activities were obviously affected by calcination temperature and reducing agent. Among them, the catalyst calcined at 500 °C and reduced with NaBH4 exhibited the best performance in this reaction. It was possibly attributed to the better dispersion of palladium particles on γ-Al2O3. Furthermore, reaction parameters were also optimized. Under optimal conditions (PN/PA molar radio 1:1, toluene as solvent), BPA was obtained in 87.9% yield with 95.6% conversion over the above catalyst. Meanwhile, split of PN was observed. A probable mechanism of retro-Michael reaction was also proposed.

Microstructure and Wear Resistance of in situ Porous TiO/Cu Composites

Qingdong Qin,Bowei Huang,Wei. Li 대한금속·재료학회 2016 METALS AND MATERIALS International Vol.22 No.4

An in situ porous TiO/Cu composite is successfully prepared using powder metallurgy by the reaction of Ti2CO and Cu powder. Morphological examination of the composite shows that the porosity of composites lies in the range between 10.2% and 35.2%. Dry sliding un-lubricated wear tests show that the wear resistance of the composite is higher than that of the Cu-Al alloy ingot. The coefficient of friction test shows that, as the volume fraction of the reinforced phase increases, the coefficient of friction decreases. The wear rate variation trend of the oil-lubricated wear test results is similar to that of the un-lubricated wear test results. The coefficient of friction for oil lubrication is similar for different volume fractions of the reinforced phase. The wear resistance of the composite at a sliding velocity of 200 rpm is slightly larger than that at 50 rpm. The porosity of the composites enhances the high-velocity oil-lubricated sliding wear resistance.

Water film covering characteristic on horizontal fuel rod under impinging cooling condition

Zhang Penghui,Wang Bowei,Chen Ronghua,Su G.H.,Tian Wenxi,Qiu Suizheng 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.11

Jet impinging device is designed for decay heat removal on horizontal fuel rods in a low temperature heating reactor. An experimental system with a fuel rod simulator is established and experiments are performed to evaluate water film covering capacity, within 0.0287e0.0444 kg/ms mass flow rate, 0 e164.1 kW/m2 heating flux and 13.8e91.4C feeding water temperature. An effective method to obtain the film coverage rate by infrared equipment is proposed. Water film flowing patterns are recoded and the film coverage rates at different circumference angles are measured. It is found the film coverage rate decreases with heating flux during single-phase convection, while increases after onset of nucleate boiling. Besides, film coverage rate is found affected by Marangoni effect and film accelerating effect, and surface wetting is significantly facilitated by bubble behavior. Based on the observed phenomenon and physical mechanism, dry-out depth and initial dry-out rate are proposed to evaluate film covering potential on a heating surface. A model to predict film coverage rate is proposed based on the data. The findings would have reliable guide and important implications for further evaluation and design of decay heat removal system of new reactors, and could be helpful for passive containment cooling research.

Evacuation of Nursing Home Based on Massmotion: Effect of the Distribution of Dependent Elderly

Jia Li,Jinghong Wang,Bowei Jin,Yan Wang,Youran Zhi,Zhirong Wang 대한토목학회 2020 KSCE Journal of Civil Engineering Vol.24 No.4

As dramatically increased elderly population, China is entering a society of deep aging. Due to the decline of physical functions, the elderly move slowly and have difficulty in escape. Hence, enough attention should be paid on pedestrian crowds’ evacuation in a nursing home. This paper takes Chinese old-age care institutions as the research object. Using the Massmotion based on the social force to establish the evacuation model and setting the parameters according to the movement characteristics of the elderly, this paper studied the influence of the dependent elderly on evacuation efficiency when they are distributed to the higher floors of the nursing home in different proportions. The results show that the evacuation time is significantly prolonged with the increase of the proportion of dependent elderly, and there is a controllable critical value for the proportion of dependent elderly. Aspeed-up phenomenon is observed when the old man enters the landing from the stairway, and meanwhile, with the increase of the proportion of dependent elderly, the acceleration position is gradually advanced, while the instantaneous speed declines. The results of this study can provide references in properly arranging the distribution of elderly accommodation and safe evacuation of the aged care institutions.

Progress of infrared guided-wave nanophotonic sensors and devices

Ma Yiming,Dong Bowei,Lee Chengkuo 나노기술연구협의회 2020 Nano Convergence Vol.7 No.12

Nanophotonics, manipulating light–matter interactions at the nanoscale, is an appealing technology for diversified biochemical and physical sensing applications. Guided-wave nanophotonics paves the way to miniaturize the sensors and realize on-chip integration of various photonic components, so as to realize chip-scale sensing systems for the future realization of the Internet of Things which requires the deployment of numerous sensor nodes. Starting from the popular CMOS-compatible silicon nanophotonics in the infrared, many infrared guided-wave nanophotonic sensors have been developed, showing the advantages of high sensitivity, low limit of detection, low crosstalk, strong detection multiplexing capability, immunity to electromagnetic interference, small footprint and low cost. In this review, we provide an overview of the recent progress of research on infrared guided-wave nanophotonic sensors. The sensor configurations, sensing mechanisms, sensing performances, performance improvement strategies, and system integrations are described. Future development directions are also proposed to overcome current technological obstacles toward industrialization.