Nanofibrous Membranes with High Air Permeability and Fluffy Structure based on Low Temperature Electrospinning Technology

Siying Lin,Xiang Huang,Zhenxiang Bu,Zhihong Lin,Peiqin Xie,Xiaolong Lin,Lingyun Wang,Wenlong Lv 한국섬유공학회 2020 Fibers and polymers Vol.21 No.7

Due to its small diameter and high density, electrospun nanofiber membranes have high resistance which obstaclestheir application. In this paper, we proposed a new electrospinning method based on low-temperature, which can affect thedeposition process of electrospinning by utilizing the freezing process of steam in the receiving plate. The filling andsupporting of ice could enlarge the pores of membranes and intervals among fibers, which caused the high porosity (92 %),rough surface, fluffy structure and low pressure drop (123 Pa) of polyvinylidene fluoride (PVDF) nanofibrous membranes. The results suggested that the electrospinning method is a promising way to prepare nanofibrous membranes with high airpermeability and fluffy structure for air filtration.

An investigation of bureaucratic influences on absorptive capacity-market responsiveness relationships

Siying Long,Zhongju Liao 기술경영경제학회 2016 ASIAN JOURNAL OF TECHNOLOGY INNOVATION Vol.24 No.1

Building on absorptive capacity and bureaucracy research, we investigate in this paper howbureaucracy within organisations moderates the relationship between absorptive capacityand market responsiveness. Using data collected from 254 firms in China, we show that theeffects of absorptive capacity on market responsiveness are contingent upon the degree ofbureaucracy within organisations. In particular, the results indicate that the positive effectsof absorptive capacity on market response speed become less positive under higher degreesof bureaucracy

Conditioned Medium Enhances Osteogenic Differentiation of Induced Pluripotent Stem Cell-Derived Mesenchymal Stem Cells

Siying Zhong,Xufeng He,Yuexia Li,Xiangxin Lou 한국조직공학과 재생의학회 2019 조직공학과 재생의학 Vol.16 No.2

BACKGROUND: Recent studies have shown that induced pluripotent stem cells (iPSCs) could be differentiated into mesenchymal stem cells (MSCs) with notable advantages over iPSCs per se. In order to promote the application of iPSCMSCs for osteoregenerative medicine, the present study aimed to assess the ability of murine iPSC-MSCs to differentiate into osteoblast phenotype. METHODS: Osteogenic differentiation medium, blending mouse osteoblast-conditioned medium (CM) with basic medium (BM) at ratio 3:7, 5:5 and 7:3, were administered to iPSC-MSCs, respectively. After 14 days, differentiation was evaluated by lineage-specific morphology, histological stain, quantitative reverse transcription-polymerase chain reaction and immunostaining. RESULTS: The osteogenesis-related genes, alp, runx2, col1 and ocn expressions suggest that culture medium consisting of CM:BM at the ratio of 3:7 enhanced the osteogenic differentiation more than other concentrations that were tested. In addition, the alkaline phosphatase activity and osteogenic marker Runx2 expression demonstrate that the combination of CM and BM significantly enhanced the osteogenic differentiation of iPSC-MSCs. CONCLUSION: In summary, this study has shown that osteoblast-derived CM can dramatically enhance osteogenic differentiation of iPSC-MSCs toward osteoblasts. Results from this work will contribute to optimize the osteogenic induction conditions of iPSC-MSCs and will assist in the potential application of iPSC-MSCs for bone tissue engineering.

Scalable graphene composite membranes for enhanced ion selectivity

Li, Siying,Lee, Jung-Hun,Hu, Qicheng,Oh, Tae-Sik,Yoo, Ji-Beom Elsevier 2018 Journal of membrane science Vol.564 No.-

<P><B>Abstract</B></P> <P>Unintended defects are a significant problem for mass production of graphene membranes. Herein, we report a method to fabricate scalable CVD graphene polymer membranes through the formation of a polysulfone (PSf) supporting layer, which is capable of duplicating the Cu morphology. Unintended defects were limited by minimizing defects associated with graphene wrinkles and eliminating polymer residues used in the transfer process. Consequently, the KCl leakage by diffusion of raw graphene membranes fabricated with this method was only ~ 0.5% that of the supporting membrane; there was also no water flux under a pressure of 20 bar. Excellent ion selectivity was achieved by controlling the duration of H<SUB>2</SUB> plasma treatment. The selectivity of KCl over NaCl was 2.61, the selectivity of KCl over MgCl<SUB>2</SUB> was 15.62, and the selectivity of NaCl over MgCl<SUB>2</SUB> was 5.98.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Polysulfone formed in Ethanol coagulation bath performed better permeability comparing to that formed in water coagulation bath. </LI> <LI> Cu foil morphology was duplicated by liquid phase PSf solution to minimize additional graphene wrinkles and unintended defects. </LI> <LI> ~ 0.5% KCl leakage by diffusion of raw graphene membranes that of the supporting membrane. </LI> <LI> Artificial graphene defects were enlarged and controlled with hydrogen plasma. </LI> <LI> The membrane exhibited an excellent selectivity among KCl, NaCl, MgCl<SUB>2</SUB> salts. </LI> </UL> </P>

Arge aurora Wei sp. nov. (Hymenoptera, Argidae) from China with a key to East Asian species of Arge nipponensis group

Wan Siying,Wu Duo,Niu Gengyun,Liu Ting,Wei Meicai 한국곤충학회 2022 Entomological Research Vol.52 No.1

Arge nipponensis group is proposed for 12 East Asian species. A key to species of this group is provided. Arge aurora Wei, sp. nov., a widespread species in China is described. It has been misidentified as Arge nipponensis Rohwer, 1910 in China since 1927. Arge nipponensis Rohwer is removed from the faunal list of China. The ovipositor and genitalia of A. nipponensis are described and figured for the first time. The geographic distribution analysis indicated that geographical barriers were probably the key to the distribution of A. aurora and A. nipponensis.

Optimal Design of Electromagnetic Devices Assisted by Black Hole and Differential Evolution Algorithms

Ziyan Ren,Siying He,Liping Zhang,Yanli Qi,Chang Seop Koh 한국자기학회 2020 Journal of Magnetics Vol.25 No.3

Recently, many design problems in the field of electrical engineering tend to be more complex, which are characterized by large scale in size, strong nonlinearity for performance analysis, and multi-dimensional design parameters. Therefore, it is not easy to seek for optimum effectively by traditional optimization algorithms. In order to solve optimal design of complex practical problems, in this paper, a novel hybrid optimization algorithm based on the differential evolution algorithm and the black hole theory is proposed and investigated. The differential evolution (DE) algorithm owns good diversity and flexibility, while the black-hole based optimization algorithm (BHBO) possesses faster convergence. In addition, these two algorithms have simple structures. The proposed algorithm with better merits combination may guarantee better convergence and stronger robustness than its independent counterparts of DE and BHBO. The searching performance is deeply investigated through numerical experiments on benchmark functions and practical electromagnetic applications.

A Possibility-Based Robust Optimal Design Algorithm in Preliminary Design Stage of Electromagnetic Devices

Ziyan Ren,Siying He,Dianhai Zhang,Yanli Zhang,Chang-Seop Koh IEEE 2016 IEEE transactions on magnetics Vol.52 No.3

<P>In the early design stage of an electromagnetic device, sufficient information on uncertainties of design variables is not available. Therefore, a reliable optimal design cannot be achieved by the conventional reliability analysis, in which the probabilistic method is applied. This paper, considering the insufficient uncertainty data, proposes a possibility-based optimal design algorithm to get a robust and reliable optimal design of electromagnetic devices. The suggested algorithm adopts a possibility analysis utilizing the fuzzy set theory. In addition, to mitigate the expensive performance analysis during possibility analysis, the design sensitivity analysis is employed to construct a surrogate model. Finally, the developed algorithm is validated through applications to several examples.</P>

Identification and management the financial risks of accumulator

Yonggang Ye,Siying Lv 인하대학교 정석물류통상연구원 2009 인하대학교 정석물류통상연구원 학술대회 Vol.2009 No.10

This paper focuses on using building block approach to identify and management financial risks of acumulator which is a kind of high-riskand complex financial derivative. When the underlying asset pricek rise, the investors could earn a lot from accumulator contracts, on the contrary, there are huge potential risks if the price falls. At present, the accumulator causes enormous losses to lots of investors, eve resulting in bankruptcy. These investors were not fully aware of the potential risks. This paper uses financial building blocks approach to decompose the accumulator into a number of well-known financial derivatives, helping investors to analyze the potential investment risks of accumulator contracts in different economic situations. Then base on the essential characteristics of accumulator, this paper proposes and testifies the proposal of hedging, making investors be fully aware of the risks of accumulator and managing the financial risks.

HVAC System Energy-saving Design for One Super-high Office Building

Weicheng, Zhang,Siying, Teng Council on Tall Building and Urban Habitat Korea 2013 International journal of high-rise buildings Vol.2 No.4

This building is a first-class super-high office building. This article briefly introduces energy-saving technique and measures adopted in HVAC system, such as cooling and heat sources, water and air system etc.

Numerical simulation of surface roughness effects on the vortex-induced vibration of a circular cylinder at a subcritical Reynolds number

Chen Wei,Wang Siying,Shi Xiaotao,Rheem Chang-Kyu,Lin Yongshui,Liu Erpeng 대한조선학회 2022 International Journal of Naval Architecture and Oc Vol.14 No.1

The Vortex-Induced Vibration (VIV) of a circular cylinder with different surface roughness is numerically simulated at a subcritical Reynolds number of 3900. The effects of surface roughness on the vibration response amplitude, hydrodynamic coefficients and wake vortex are analyzed. The results show that as surface roughness increases, four branches (initial, upper, super-upper and lower branches) appear in the VIV response for a smooth cylinder, and for a cylinder with a small surface roughness of KS=D ¼ 2:5 103 , this response changes to three branches (initial, upper and lower branches). The vortex shedding for the initial and lower branches is 2S mode, and that for the upper and super-upper branches (lock-in range) is P þ S, PþSþ and 2P modes. With increasing surface roughness, the maximum amplitude has little difference, and the width of the lock-in range increases. A large jump in the vortex phase at the transition of the initial and upper branches and a large jump in the total lift phase at the transition of the upper and lower branches are found, and these jumps are associated with a switch in the timing of vortex shedding (jump of the vortex phase: 2S mode to P þ S mode; jump of the lift phase: other modes to 2S mode). The results are significant for the development of flow and vibration control technology.