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Shuguang Li,M. Waqas,Salman A. AlQahtani,M. Ijaz Khan 한국자기학회 2023 Journal of Magnetics Vol.28 No.2
Enhancing heat transfer is of utmost importance in modern industrial applications. Pure liquids for illustration ethylene glycol, propylene glycol and water having lower conductivity are commonly used as cooling liquids in distinct applications. This approach helps conserve and optimize the enhancement of heat transportation. However, in order to achieve enhanced thermal efficiency, state-of-the-art liquids known as nanoliquids have been recommended. Thus the Buongiorno two-component nanoliquid model, which exhibits superior thermal efficiency compared to the aforementioned standard cooling liquids is being considered for formulating and analyzing the behavior of Casson nanoliquid configured by cylindrical convected surface. The problem formulation incorporates various factors such as Darcy-Forchheimer porosity, thermophoresis, magnetohydrodynamics, Brownian diffusion, suction/injection and Joule heating. Boundary-layer stretching flow is formulated. Dimensionless differential form from governing nonlinear problems is achieved by employing relevant variables. The application of the homotopy procedure results in convergent solutions for strongly nonlinear systems. The graphs are used to reveal the plots of significant factors in the analysis.
Shuguang Li,Yanxia Feng,Jiankun Qin,Shuai Li,Gaoyuan Ye,Yingcheng Hu 한국섬유공학회 2019 Fibers and polymers Vol.20 No.10
In this study, a bi-directional corrugated lattice sandwich structure was fabricated from jute fibers and epoxy resin. Die casting was used to prepare the core struts and face sheets and two fiber composites were designed to produce structuralstruts. The configuration and the relative density of the core layer were altered. In addition, the three-point bending propertiesof each configuration were investigated to explore the various modes of failure, destruction processes, and mechanicalproperties. Results of the experiments show that failure mainly occurs via three modes: face sheet crushing, face sheetwrinkling, and core member crushing. Moreover, the failure mode is related to the strength of the core struts. Theoreticalcalculations and finite element analysis were carried out, and the simulation results were in good agreement withexperimental results, the relative errors of displacement and load are all within 20 %. In conclusion, the proposed sandwichbeam configuration composed of jute fibers could be highly useful for enhancing engineering structurer owing to the simplefabrication process, moreover, the materials are environmentally friendly and inexpensive.
Improved high-k stacks with chemical oxide interfacial layer by DPN/ PNA treatment
Shuguang Li,Ying-Tsung Chen,Shoou-Jinn Chang 한국물리학회 2015 Current Applied Physics Vol.15 No.3
A decoupled plasma nitridation (DPN) with post nitridation annealing (PNA) treatment method was introduced to improve the performances of MOS devices with high-k (HK)-last/gate-last integration scheme and chemical oxide interface layer (IL). By introducing N to form HfSiON, it was found that DPN + PNA treatments could provide smaller equivalent oxide thickness (EOT) for both nMOS and pMOS devices. It was also found that we could achieve the best overall device performance for the HK-last/gatelast integration scheme with a chemical oxide IL by introducing nitrogen gas with low percentage content during DPN followed by high temperature PNA.
Performance Analysis of IEEE 802.15.4e Time Slotted Channel Hopping for Low-Rate Wireless Networks
( Shuguang Chen ),( Tingting Sun ),( Jingjing Yuan ),( Xiaoyan Geng ),( Changle Li ),( Sana Ullah ),( Mohammed Abdullah Alnuem ) 한국인터넷정보학회 2013 KSII Transactions on Internet and Information Syst Vol.7 No.1
The release of IEEE 802.15.4e specification significantly develops IEEE 802.15.4. The most inspiring improvement is the enhancement for medium access control (MAC) sublayer. To study the performance of IEEE 802.15.4e MAC, in this paper we first present an overview of IEEE 802.15.4e and introduce three MAC mechanisms in IEEE 802.15.4e. And the major concern here is the Time Slotted Channel Hopping (TSCH) mode that provides deterministic access and increases network capacity. Then a detailed analytical Markov chain model for TSCH carrier sense multiple access with collision avoidance (CSMA-CA) is presented. Expressions which cover most of the crucial issues in performance analysis such as the packet loss rate, energy consumption, normalized throughput, and average access delay are presented. Finally the performance evaluation for the TSCH mode is given and we make a comprehensive comparison with unslotted CSMA-CA in non-beacon enabled mode of IEEE 802.15.4. It can validate IEEE 802.15.4e network can provide low energy consumption, deterministic access and increase network capacity.
INSTANTONS ON CONIC 4-MANIFOLDS: FREDHOLM THEORY
Li, Weiping,Wang, Shuguang Korean Mathematical Society 2007 대한수학회지 Vol.44 No.2
We study the self-duality operator on conic 4-manifolds. The self-duality operator can be identified as a regular singular operator in the sense of $Br\"{u}ning$ and Seeley, based on which we construct its parametrizations and closed extensions. We also compute the indexes.
Reactivity of Brönsted acid ionic liquids as dual solvent and catalyst for Fischer esterifications
Zuojun Wei,Feijin Li,Huabin Xing,Qilong Ren,Shuguang Deng 한국화학공학회 2009 Korean Journal of Chemical Engineering Vol.26 No.3
Several water-stable ionic liquids with different acidity and affinity were synthesized and applied as both solvents and acid catalysts for Fischer esterification of ethanol reacting with four aliphatic carboxylic acids (acetic acid, n-hexanoic acid, lauric acid, and stearic acid). Among the studied ionic liquids, [(n-bu-SO3H) MIM][HSO4] (3-butyl- 1-(butyl-4-sulfonyl) imidazolium sulfate) and [(n-bu-SO3H) MIM][p-TSO] (3-butyl-1-(butyl-4-sulfonyl) imidazolium toluenesulfonate) show higher reactivity for the production of ethyl esters. The catalytic activities of these ionic liquids are strongly dependent on the acidity of their anions and cations, as well as their hydrophilicity and affinity with the reactants. Water refluxing through the condenser may be another important reason for obtaining high conversion of esterification, indicating a water-sequester process is still needed in order to obtain a higher yield of ester in the ionic liquid catalyzed esterification system. Kinetics studies show the conversions of the acids increase with reaction temperature and time, and reach equilibrium within about two hours. The apparent activation energies are 39.1±2.0, 49.7± 2.5, 51.4±2.5 and 59.3±3.0 kJ·mol−1 for the formation of ethyl acetate, ethyl n-hexanoate, ethyl laurate and ethyl stearate, respectively.
Jianping Shen,Siwei Zhang,Wei Wang,Shuguang Li,Song Zhang,Yujun Wang 한국광학회 2021 Current Optics and Photonics Vol.5 No.3
A tapered As 2 S 3 photonic crystal fiber (PCF) with four layers of air holes in a hexagonal array around the core is designed in this paper. Numerical simulation shows that the dispersion D decreases and the nonlinearity coefficient γ increases from the thick to the thin end along the tapered PCF. We simulate the midinfrared pulse compression in the tapered As 2 S 3 PCF using the adaptive split-step Fourier method. Initial Gaussian pulses of 4.4 ps and a central wavelength of 2.5 μm propagating in the tapered PCF arelocated in the anomalous dispersion region. With an average power of assumed input pulses at 3 mW and a repetition frequency of 81.0 MHz, we theoretically obtain a pulse duration of 56 fs and a compression factor of 78 when the pulse propagates from the thick end to the thin end of the tapered PCF. When confinement loss in the tapered PCF is included in the simulation, the minimum pulse duration reaches 72 fs; correspondingly, the maximum compression factor reaches 61. The results show that in the anomalous-dispersion region, midinfrared pulses can be efficiently compressed in a dispersion-decreasing and nonlinearity-increasing tapered As 2 S 3 PCF. Due to confinement loss in the tapered fiber, the efficiency of pulse compression is suppressed.
Regenerative Er-doped Fiber Amplifier System for High-repetition-rate Optical Pulses
Yan Liu,Kan Wu,Nanxi Li,Lanling Lan,Seongwoo Yoo,Xuan Wu,Perry Ping Shum,Shuguang Zeng,Xinyu Tan 한국광학회 2013 Current Optics and Photonics Vol.17 No.5
A regenerative Er-doped fiber amplifier system for a high-repetition-rate optical pulse train is investigated for the first time. A signal pulse train with a wavelength tuning range of 18 nm is produced by a passive mode-locked fiber laser based on a nonlinear polarization rotation technique. In order to realize the amplification, an optical delay-line is used to achieve time match between the pulses’ interval and the period of pulse running through the regenerative amplifier. The 16 dB gain is obtained for an input pulse train with a launching power of -30.4 dBm, a center wavelength of 1563.4 nm and a repetition rate of 15.3 MHz. The output properties of signal pulses with different center wavelengths are also discussed. The pulse amplification is found to be different from the regenerative amplification system for CW signals.