Oscillations of Neutral Difference Equations

ZHOU, YONG KYUNGPOOK UNIVERSITY 1999 Kyungpook mathematical journal Vol.39 No.2

In this paper, we establish some sufficient conditions for the oscillations of all solutions of the neutral difference equation with positive and negative coefficients. Our results improve the known results in the literature.

Insect-specific microRNA involved in the development of the silkworm Bombyx mori

Yong Zhang,Xue Zhou,Xie Ge,Jiang-Hao Jiang,Mu-Wang Li,Shi-Hai Jia,Xiao-Nan Yang,Yun-Chao Kan,Xue-Xia Miao,Guo-Ping Zhao,Fei Li,Yong-Ping Huang 한국응용곤충학회 2009 한국응용곤충학회 학술대회논문집 Vol.2009 No.10

MicroRNAs (miRNAs) are endogenous non-coding genes that participate in post-transcription regulation by either degrading mRNA or blocking its translation. It is considered to be very important in regulating insect development and metamorphosis. Insects are the largest group of animals and are extremely valuable in biological and agriculture research. Insects are also important pests to human health and agriculture, and efforts are necessary protect both humans and plants from disease and damage. Despite their importance, insects lag behind mammals, nematodes, and plants in miRNA research. At present, only 279 insect miRNAs have been identified from Drosophila melanogaster, Anopheles gambiae, Apis mellifera, Bombyx mori, and D. pseudoobscura in miRBase, and most of these miRNAs were computationally predicted without experimental validation. Functional analysis of insect miRNAs has only been conducted in D. melanogaster.

Classification and existence of nonoscillatory solutions of higher order nonlinear neutral difference equations

Yong Zhou,C. F. Li 한국전산응용수학회 2005 Journal of applied mathematics & informatics Vol.18 No.1-2

In this paper, we consider the higher order nonlinear neutral delay difference equation of the form r(xn + pxn−) + f(n, xn−1(n), xn−2(n), . . . ,xn−m(n)) = 0. We give an integrated classification of nonoscillatory solutions of the above equation according to their asymptotic behaviours. Necessary and suffi- cient conditions for the existence of nonoscillatory solutions with designated asymptotic properties are also established.

Design, performance analysis, and testing of a GFRP racetrack ring for a high-temperature superconducting motor with a flexible support rotor

Yong Zhou,Feng Xie,Hai-Yuan Jia,Wei Chen 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.10

A conceptual 20 MW high-temperature superconducting (HTS) motor (HTSM) with a novel glass-fiber reinforced plastic (GFRP) racetrack ring in the flexible support rotor was explored in this study. To support the cold mass at operating conditions, the high-strength, lowleakage GFRP racetrack ring was designed as follows. First, conceptual design of the 20 MW HTSM was conducted, and the torque transmitted by the GFRP racetrack rings was obtained through electromagnetic analysis. Second, a GFRP racetrack ring was designed, and its total cross-sectional area was obtained through theoretical analysis. Third, thermal leakage and stress were calculated and examined through theoretical and finite element analyses, respectively. The GFRP racetrack ring with the “D” ring was selected based on the results. The thickness and width of the GFRP ring were set to 16 and 10 mm, respectively, and the thickness of the “D” ring was 3 mm. Then, a full-scaled GFRP ring was fabricated, and its strength and stiffness were tested via room-temperature and low-temperature tensile tests. The average tensile strength and average Young’s modulus of the GFRP ring at room temperature were 1131.5 MPa and 49.9 GPa, respectively. The strength of the GFRP ring at 193.4 K was 1243.9 MPa, and the Young's modulus of the GFRP ring at 141.3 K was 69 GPa. Lastly, a new 200 kW HTS generator was assembled using a scaled rotor with the same structure as the 20 MW HTSM and the original stator of an existing 200 kW generator. The test system was built to evaluate the feasibility of the GFRP ring before manufacturing the 20 MW HTSM. Test results showed that the GFRP ring is feasible, the design method of the GFRP ring is credible. The GFRP ring is suitable for the cold mass support of HTSMs and other low-temperature devices.

A Pole Pair Segment of Oil-cooling Air-Core Stator for a 2 MW Direct-Drive High Temperature Superconducting Wind Power Generator

Zhou Yong,Dong Qi,Niu Xiao-Jun,Xu Hong,Xiong Qi,Su Hao,Zheng Jun 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.6

A 2 MW direct-drive (DD) high temperature superconducting (HTS) wind power generator with HTS wires in the rotor fi eld windings and copper transposed conductor in the stator coils was explored for the wind turbine application in this study. An oil-cooling air-core stator with non-magnetic teeth of the 2 MW DD HTS generator was designed because the high fl ux density generated by the HTS wires wound result in larger dissipation in iron teeth, and the process of that could be summarized as follows. First, a 2 MW DD HTS wind power generator was designed, and the electromagnetic (EM), loss, EM force, and insulation of the DD HTS generator were analyzed and developed, respectively. Second, the thermal and mechanical of the one pole pair oil-cooling air-gap armature was analyzed by the fi nite element analysis. Then, a pole pair segment of the oil-cooling air-core stator with the same structure as the 2 MW generator was designed and manufactured to identify potential challenges, obtain practical knowledge before production, and then reduce the development risk of the 2 MW DD HTS generator. Furthermore, a test system with converter, oil-cooling system, and data acquisition equipment was developed simultaneously to test the temperature distribution of the slotless stator. The performance test results show that the maximum temperature rise of the one pole pair oil-cooling stator under rated conditions is about 81.4 K, which satisfi es the design requirements of the 2 MW DD HTS generator.

Isolation and Purification of Thermostable β-Mannanase from Paenibacillus illinoisensis ZY-08

( Yong Seok Lee ),( Y. Zhou ),( In Hye Park ),( Muni Ramanna Gari Subhosh Chandra ),( Soon Cheol Ahn ),( Yong Lark Choi ) 한국응용생명화학회 2010 Applied Biological Chemistry (Appl Biol Chem) Vol.53 No.1

A bacterium, ZY-08 that produced extracellular mannanase, was isolated and identified as Paenibacillus illinoisensis (P. illinoisensis) on the basis of 16S rDNA phylogenetic analysis. The enzyme was purified to apparent homogeneity by ultrafiltration, DEAE-Sepharose chromatography, and Sephadex G-50 chromatography procedures. The β-mannanase was purified 3.5 fold to homogeneity with a final recovery of 22% and specificity of 9.3 U/mg protein as judged by SDS-polyacrylamide gel electrophoresis. The molecular mass was about 60 kDa. It was active at 60˚C and pH 6.0 and it`s retained about 40% of activity at 70˚C, with a broad pH range of 3.0-6.0. The mannanase was highly specific towards glucomannan and galactomannan, but exhibited very low activity towards starch, carboxy-methyl cellulose, and birchwood xylan. Result of thin-layer chromatography analysis showed that the enzyme produced various kinds of oligosacchrides. These unique properties of the thermostable mannanase and broad substrate specificity (low activity towards cellulosic substrates) from P. illinoisensis ZY-08 make this enzyme attractive for biotechnological applications.

Design and testing of CFRP sleeve for a high-speed permanent magnet synchronous motor with surface-mounted rotor

Yong Zhou,Lei Tian,Sheng-Hua Gao,Jing-Wei Zhang,Lin-Ke Yang,Rui-Guang Xie 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.1

A high-speed (HS) permanent magnet (PM) synchronous motor (HSPMSM) with a carbon fiber-reinforced plastic (CFRP) protective sleeve in the surface-mounted rotor was explored in this study. In view of retaining the PMs at HS operations, the high-strength CFRP sleeve was designed on the basis of a process that could be summarized as follows. First, a multi-physics analysis of the rotor was conducted. The requirements to the CFRP sleeve were obtained from electromagnetic analysis, loss analysis, heat flow coupling computational fluid dynamics analysis, structural analysis, and rotor dynamics analysis. Second, the CFRP sleeve was designed by theoretical analysis. From the results, the thickness values of the carbon fibers in the circumferential and helical directions were chosen to be 4 and 1 mm, respectively, while the helical angle of carbon fibers was chosen to be 70°. Then, a plateshaped CFRP product and a cylindrical CFRP product were fabricated to verify the strength and stiffness of the CFRP sleeve. The performance test results show that the hoop strength and elastic modulus and the axial strength and elastic modulus of the plate-shaped CFRP products at 20 °C are 1963 MPa @ 156 GPa and 550 MPa @ 36 GPa, respectively. The hoop strain and axial strain of the cylindrical CFRP product under 35 MPa are about 3000 and 1900 με, which meet the design requirements of the HSPMSM.

Simulation of Permeation of Saturated Cement Paste Based on a New Meso-scale Pore Network Model

Yong Zhou,Yuxuan Yang,Bigya Gyawali,Weiping Zhang 한국콘크리트학회 2021 International Journal of Concrete Structures and M Vol.15 No.5

This paper presents the simulation of the permeation of saturated cement paste based on a novel pore network model. First, a 2D hydration model of cement particles was developed by extending the work of Zheng et al. 2005 to provide the background for the network construction. Secondly, the establishment of the pore network model and simulation of permeation of saturated cement paste were carried out. The irregular pores between any two hydrated cement particles were linearized with clear distances as the diameters of pores. The straight tubular pores were interconnected with one another to form the network model. During this process, the weighted Voronoi diagram was employed to operate on the graphical expression of the hydrated cement particles. Water permeation in saturated cement paste was simulated to verify the pore network model. Finally, the factors including water-cement ratio, reaction temperature, reaction time and cement particle size that would influence water permeation were numerically investigated.

Experimental Study of Molecular Immune Mechanism of TGCO Anti-Adjurant Arthritis

Zhou, Yong,Li, Jianmin,Wang, Xudan 경희대학교 2001 INTERNATIONAL SYMPOSIUM ON EAST-WEST MEDICINE Vol.2001 No.1

The total glycosides of cornus officinal (TGCO) is effective part of cornus officinals, TGCO suppress immune reactions has been reported in vivo or in vitro. In this paper, we researched effect of TGCO on rat adjuvant arthritis and its molecular immune mechanism. The results showed that TGCO had better action of curing to rat AA, suppressing joint swell of primary and secondary recreation to adjuvant, improving of pathological changes of joints and alleviating spain. On above basis, we forward investigated the molecular immune mechanism TGCO anti-AA, the main results showed such as: 1. TGCO could suppress T lymphocytes proliferation stimulated with ConA and DTH reaction induced by PPO in AA rats. 2. TGCO suppress production of IL-1, IL-6 and TNFα of peritoneal macrophages from AA rats, and PEG2 in plasma of AA rats.3. TGCO could suppress expression of iNOS mRNA gene and IL-lra mRNA gone of peritoneal macrophage of AA rats. 4. Cell-ELISA method was used to detect adhesion molecules(ICAM-1, CD44) and integrin (α4 β7) on ECV 304(It is an important endothelial cell line derived from HUVEC), TGCO could inhibit ECV304 expressing adhesion molecules (ICAM-1, CD44) and integrin(α4β7), with TNF-α and IL-1 stimulate in vitro. Summarizing above results, we infer that TGCO can cure rat AA is in relation to suppressing cell-mediated immune, anti inflammation cytokine(IL-1. IL-6 and TNF-α), and inhibiting adhesion molecule expression.

Competition and Coordination for the Dual-channel Supply Chain with Channel Preference

ZHOU Yong-wei,FAN He-hua,LI Yan-chao 보안공학연구지원센터 2016 International Journal of u- and e- Service, Scienc Vol.9 No.2

Aiming at the dual-channel supply chain system with the manufacturer owned direct channel and retail channel simultaneously, the consumers are divided into retail channel loyalty and brand loyalty two parts, under the condition of market demand are depend on the consumers’ channel preference, we studied to the pricing game and coordination between the manufacturer and retailer. The research result showed that the Nash equilibrium of price exists in centralized and decentralized supply chain system, the channel preference degree of consumers, the number of brand loyalty consumers are all have certain influence on supply chain’s optimal pricing strategy, and the price markup contract can realize the coordination of supply chain. The numerical experiment has showed the effectiveness of the conclusions.