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Search Results: 1 - 10 of 130426 matches for " Yun Wang "
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Optimization of solvent extraction conditions for total carotenoids in rapeseed using response surface methodology  [PDF]
Ling Wang, Yun Liu
Natural Science (NS) , 2009, DOI: 10.4236/ns.2009.11005
Abstract: The optimum total carotenoids (TC) extraction from rapeseed with solvent extraction method by UV-visible spectrophotometer determination was investigated by using response surface methodology (RSM). Extraction duration, re-peated extraction cycles, solvent-solid ratio and extraction temperature were assumed to be the most important factors affecting solvent extrac-tion for the determination of TC. Optimum sol-vent extraction conditions for maximizing the determination of TC were: extraction duration 7.3h, repeated extraction three times, ratio of solvent-solid (v/w, mL/mg) 29:1, extraction temperature 42°C. Under the optimal conditions, the yield of TC was up to 4.79 mg /100g. The model had a satisfactory coefficient of R2 (= 0.912) and verified experimentally. The results showed that the conditions were mild and use-ful for maximizing a quantitative spectropho-tometer determination of TC in rapeseed.
The Analysis of the Structure and Security of Home Control Subnet  [PDF]
Chengyi WANG, Yun ZHANG
Wireless Sensor Network (WSN) , 2009, DOI: 10.4236/wsn.2009.11009
Abstract: A lot of technologies can be used in home control subnet, but the hardware and software resources available for the home control subnet are limited. There are security problems easily seen. The paper gives the system-atic analysis of the structure and function of home control subnet based on the general model of home net-work. The paper has also analyzed two types of major equipment, namely sub-gateways and terminal equip-ment. The major networking technology used in home control subnet is summarized and concluded. In com-bination with relationship among home control subnet, home network, as well as the outside main network, the paper has systematically studied various safety problems related to home control gateways and the possi-ble solutions to those problems have been made.
The Clinical Outcomes of Transforaminal Percutaneous Endoscopic Discectomy in Treating Lumbar Disc Herniation: A Review  [PDF]
Bheemasetty Rakesh, Yun Tao Wang
Open Journal of Orthopedics (OJO) , 2018, DOI: 10.4236/ojo.2018.82008
Abstract: Percutaneous endoscopic lumbar discectomy (PELD) is a minimally invasive technique started during the late 20th century. This process is done through microscopic view under local anesthesia. There is a growing but still insufficient evidence that lumbar EDS shows slightly better results in terms of minor tissue damage, shorter hospital stay, faster return to ordinary daily activities, and patient satisfaction. Recurrence rate still remains a matter of debate, and is related with the surgical skills of the surgeon. The complication rate seems to be similar in both of the techniques i.e., open and endoscopic. More randomized controlled trials, systematic reviews and meta-analysis are needed to clarify whether lumbar EDS can be considered comparable if not superior to standard open discectomy. In spite of lacking defined clinical evidence, lumbar EDS is without doubt a rapidly expanding PELD and its future developments are incredibly promising. Due to less complication rate this technique can be considered as a gold standard compared to the open discectomy. The surgeons still require more cadaveric practices for learning the curve and to approach the herniated disc area. The main objective of this review article is to show the clinical outcomes of the Transforaminal Percutaneous Endoscopic Discectomy in treating the lumbar disc herniation.
Nonlinear Optical Properties of Novel Polypyrrole Derivatives Bearing Different Aromatic Segments  [PDF]
Wei Zhao, Yun Wang, Aijian Wang
Materials Sciences and Applications (MSA) , 2017, DOI: 10.4236/msa.2017.811056
Abstract: Polypyrrole (PPy) and its derivatives containing different were synthesized by the interfacial polymerization reaction using ammonium per sulfate as oxidant, and were characterized by using Fourier transform infrared, Ultraviolet/visible absorption, and Raman spectroscopic techniques. The third-order nonlinear optical properties of all samples were measured by using nanosecond Z-scan measurements at 532 nm. At the identical mass concentration of 0.15 mg·mL-1, all PPy derivatives exhibited an obvious reverse saturable absorption performance, while the saturable absorption response was observed for PPy. In addition, significant differences in their nonlinear optical performances were observed, highlighting the influence on optical nonlinearity of the aromatic segments of conjugated polymers.
Synthesis and Crystal Structure of the Hydrogen Bromide Salt of 1,4,7,10-Tetrakis(2-((4-methoxy)phenoxy) ethyl)-1,4,7,10-tetraazacyclododecane  [PDF]
Wei Zhao, Yun Wang, Aijian Wang
Journal of Materials Science and Chemical Engineering (MSCE) , 2017, DOI: 10.4236/msce.2017.510001
Abstract: A novel molecule tetra-N-alkylation of cyclen (1,4,7,10-tetraazacyclododecane), 1,4,7,10-tetrakis(2-((4-methoxy)phenoxy)ethyl)-1,4,7,10-tetraazacyclododecane 1, was synthesized and structurally characterized by the single-crystal X-ray diffraction. The crystals were obtained from ethanol by slow evapora-tion at room temperature and the four hydroquinone groups of the benzene ring formed a π-electron-rich cavity by C-H···Br stacking interaction. The crystal belongs to the orthorhombic system, space group Pbcn with a = 17.3174(15), b = 12.9891(11), c = 19.3379(17) ?, α= β = γ = 90°, V = 4349.8(7) ?3, Z = 4, Dc = 1.304 g/cm3, C44H61 BrN4O8, Mr = 853.88, F(000) = 1808, μ = 1.001 mm?1, CuKa radiation (λ = 0.71073), R = 0.0434 and wR = 0.1091 for 5200 observed reflections with I > 2σ(I).
Model-Independent Distance Measurements from Gamma-Ray Bursts and Constraints on Dark Energy
Wang, Yun
High Energy Physics - Phenomenology , 2008, DOI: 10.1103/PhysRevD.78.123532
Abstract: Gamma-Ray Bursts (GRB) are the most energetic events in the Universe, and provide a complementary probe of dark energy by allowing the measurement of cosmic expansion history that extends to redshifts greater than 6. Unlike Type Ia supernovae (SNe Ia), GRBs must be calibrated for each cosmological model considered, because of the lack of a nearby sample of GRBs for model-independent calibration. For a flat Universe with a cosmological constant, we find Omega_m=0.25^{+0.12}_{-0.11} from 69 GRBs alone. We show that the current GRB data can be summarized by a set of model-independent distance measurements, with negligible loss of information. We constrain a dark energy equation of state linear in the cosmic scale factor using these distance measurements from GRBs, together with the "Union" compilation of SNe Ia, WMAP five year observations, and the SDSS baryon acoustic oscillation scale measurement. We find that a cosmological constant is consistent with current data at 68% confidence level for a flat Universe. Our results provide a simple and robust method to incorporate GRB data in a joint analysis of cosmological data to constrain dark energy.
Differentiating dark energy and modified gravity with galaxy redshift surveys
Wang, Yun
High Energy Physics - Phenomenology , 2007, DOI: 10.1088/1475-7516/2008/05/021
Abstract: The observed cosmic acceleration today could be due to an unknown energy component (dark energy), or a modification to general relativity (modified gravity). If dark energy models and modified gravity models are required to predict the same cosmic expansion history H(z), they will predict different growth rate for cosmic large scale structure, f_g(z)=d\ln \delta/d\ln a (\delta=(\rho_m-\bar{\rho_m})/\bar{\rho_m}), a is the cosmic scale factor). If gravity is not modified, the measured H(z) leads to a unique prediction for f_g(z), f_g^H(z). Comparing f_g^H(z) with the measured f_g(z) provides a transparent and straightforward test of gravity. We show that a simple \chi^2 test provides a general figure-of-merit for our ability to distinguish between dark energy and modified gravity given the measured H(z) and f_g(z). We study a magnitude-limited NIR galaxy redshift survey covering >10,000 (deg)^2 and the redshift range of 0.5
Develop Marine Economy and Protect Marine Environment
Yun Wang
International Journal of Business and Management , 2009,
Abstract: Developing marine economy and protecting marine environment has become a strategic problem that has relation to the survival and development of coastal countries. With the rapid economic development of coastal areas, the problems in marine ecological environment are becoming more and more obvious. So we should energetically develop marine economy, and strengthen the protection of marine environment and marine ecosystem so as to guarantee the sustainable development of marine economy. Meanwhile, we should insist on scientific development concept, make scientific programming in marine development, implement integrated management, and promote the construction of legal system. Besides, we should vigorously develop marine science and technology, implement the strategy of “prospering marine economy through science and technology”, and realize the “four changes”.
The Economy Evaluation of the Counties in Chongqing
Journal of Chongqing Normal University , 2012,
Abstract: The paper based on the relevant data of Chongqing Statistical Yearbook 2011, 40 districts and counties of Chongqing's economic development in 2010 was evaluated. According to their own situation in Chongqing indicators, the paper selects nine indicators: total population of year-end, gross regional product, per capita disposable income of urban residents, total fixed asset investment, district local fiscal revenue, the expenditure of the local district, total retail sales of social consumer goods, gross industrial output value,import and export value and translates them intoF1 . Based on principal component analysis, we set the formulaF = (70.145% F1 +13. 937F2 ) / 84.082%, so we set the indicators system of evaluation for Chongqing forty rural economic development. It shows that anhour economic area is better than the northeast of Chongqing, and the northeast of Chongqing is better than the southeast of Chongqing overall, among which Yubei district is the best in an hour economic areas, Wanzhou district is the best in the northeast of Chongqing,and Qianjiang district is the best in the southeast of Chongqing.
Mass and radius of cosmic balloons
Yun Wang
Physics , 1993, DOI: 10.1103/PhysRevD.49.5063
Abstract: This revised version uses Gauss-Codazzi equations to derive the exact mass and radius relations. The results remain qualitatively the same.
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