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Search Results: 1 - 10 of 104242 matches for " ZHANG Guoyu "
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Adaptive topology learning of camera networkacross non-overlapping views
Yang Biao, Lin Guoyu, Zhang Weigong
- , 2015, DOI: 10.3969/j.issn.1003-7985.2015.01.011
Abstract: An adaptive topology learning approach is proposed to learn the topology of a practical camera network in an unsupervised way. The nodes are modeled by the Gaussian mixture model. The connectivity between nodes is judged by their cross-correlation function, which is also used to calculate their transition time distribution. The mutual information of the connected node pair is employed for transition probability calculation. A false link eliminating approach is proposed, along with a topology updating strategy to improve the learned topology. A real monitoring system with five disjoint cameras is built for experiments. Comparative results with traditional methods show that the proposed method is more accurate in topology learning and is more robust to environmental changes.
DesignofOpticalandMechanicalStructureforLunarSimulatorBasedonVariableShapeandAdjustableRadiance
LIU,Shi,ZHANG,Guoyu,SUN,Gaofei,WANG,Lingyun,GAO,Yujuni
空间科学学报 , 2015, DOI: 10.11728/cjss2015.05.647
Abstract: Tosimulatethedifferentlunarphasesandensurecontinuousadjustabilityoftheradiantbrightness,anewbroadspectrumlightandfrostedglasswereappliedanddesignedintheopticalsystemforlunarsimulatorwiththeshapesandradiancebeingabletobeadjusted.Accordingtotheengineeringdemandandindexrequirementsoftheopticalsystem,threemajordesignaspectsareaddressed,includingthehighreliabilityandmaintainabilityforbroad-spectrumlight,heatdissipationinlunarsimulatorforlongworkinghours,andbearingofthemainframeunderdifferentworkingconditions.Bydesigningareasonablemachinestructure,andthroughthestructureitselfwiththematrixarrangementof48axialflowfans,aneffectivelycoolingairductisestablished.DeformationandtemperaturewerecalculatedbythefiniteelementsoftwareANSYS.Theresultsshowedthatthedisplacementdeformationreached0.33mmandstressdeformationreached0.02MPaatthetemperatureof20℃;whenthemainframewasinthetemperaturefieldbetween20℃and65℃,themaximumdisplacementdeformationreached13.30mmandmaximumstressdeformationis97.90MPa,andtheamountofthisdeformationisverysmallinconsideringofthemechanicalstructuredimensionsandweightofthelunarsimulator.
Experimental analysis of the slip sinkage effectbased on real vehicle test
Yang Fan, , Lin Guoyu, Zhang Weigong, Wang Ningbo
- , 2016, DOI: 10.3969/j.issn.1003-7985.2016.02.012
Abstract: To improve the semi-empirical model, the slip sinkage effect is analyzed based on the real vehicle test. A dynamic testing system is used to gain the dynamic responses of wheel-soil interactions. The Gauss-Newton algorithm is adopted to estimate the undetermined parameters involved in the slip sinkage models. Wong’s original model is compared with three typical slip sinkage models on the prediction performance of a drawbar pull. The maximum error rate, root mean squared error and correlation coefficient are utilized to evaluate the performance. The results indicate that the slip sinkage models outperform Wong’s model and greatly improve the prediction accuracy. Lyasko’s model is confirmed as an outstanding one for its comprehensive performance. Hence, the existence of the slip sinkage effect is validated. Lyasko’s model is selected as an optimal one for the practical evaluation of military vehicle trafficability.
Hydrogel Contact Lens for Extended Delivery of Ophthalmic Drugs
Xiaohong Hu,Lingyun Hao,Huaiqing Wang,Xiaoli Yang,Guojun Zhang,Guoyu Wang,Xiao Zhang
International Journal of Polymer Science , 2011, DOI: 10.1155/2011/814163
Abstract: Soft contact lenses can improve the bioavailability and prolong the residence time of drugs and, therefore, are ideal drug carriers for ophthalmic drug delivery. Hydrogels are the leading materials of soft contact lenses because of their biocompatibility and transparent characteristic. In order to increase the amount of load drug and to control their release at the expected intervals, many strategies are developed to modify the conventional contact lens as well as the novel hydrogel contact lenses that include (i) polymeric hydrogels with controlled hydrophilic/hydrophobic copolymer ratio; (ii) hydrogels for inclusion of drugs in a colloidal structure dispersed in the contact lenses; (iii) ligand-containing hydrogels; (iv) molecularly imprinted polymeric hydrogels; (v) hydrogel with the surface containing multilayer structure for drugs loading and releasing. The advantages and disadvantages of these strategies in modifying or designing hydrogel contact lenses for extended ophthalmic drug delivery are analyzed in this paper. 1. Introduction Ocular disorders frequently occur in human body, which are mainly treated by drugs. In therapy uses, the drugs could present some side effects to the human body and even harm the normal tissues when their concentration is too high. On the other side, the drugs will not treat the diseases effectively when their concentration is too low [1]. Moreover, the treatments of ocular disorders are frequently slow processes extending from several days to several weeks. Therefore, the effective therapy must depend on the rational drug concentration and residence time. 90% or more of drugs used in ocular disorder therapy are in the form of eye drops or eye ointments [1]. Only 1–5% of the drugs contained in the eye drops can be effectively used, while a large part of the drugs enters the systemic circulation by either conjunctival uptake or drainage into the nasal cavity. Moreover, the residence time of eye drops is only 2?min or so [2]. These characteristics of eye drops cause inconvenient use, low efficiency, ineffective therapy, severe side effects, and so forth. Although eye ointments may be resident on the eye much longer than eye drops, they may affect the sight and irritate eye tissue [1, 3–5]. In order to overcome the disadvantages of eye drops and eye ointments, numerous strategies have been developed for the treatment of ocular disorders including increasing the viscosity of the eye drops and increasing the corneal permeability. Though these strategies may increase the drugs residence time and the bioactivities, they
The Risk Behaviors and Mental Health of Detained Adolescents: A Controlled, Prospective Longitudinal Study
Zhenhua Zhou, Hongyan Xiong, Ran Jia, Guoyu Yang, Tianyou Guo, Zhaoyou Meng, Guangyu Huang, Yao Zhang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0037199
Abstract: Background To assess the behavioral risk factors and mental health needs of adolescents in juvenile detention centers (JDC). Method A total of 238 boys aged 12–17 years was surveyed who had been admitted to a detention center and compared them with boys from the community (n = 238) matched for sex and age. We assessed behavioral risk factors and mental health problems by using the Youth Risk Behavior Survey questionnaire (YRBS) and the Youth Self-Report questionnaire (YSR). Results Young offenders had significantly higher YRBS scores than controls for drug use (odds ratio (OR) 5.16, 95% CI 2.27–7.84), sexual intercourse (OR, 2.51; 95% CI 1.55–2.90), irregular diet (4.78, 2.11–7.51), suicide attempts (1.96, 1.32–5.85), and physical fighting behavior (3.49, 1.60–7.07), but not for tobacco use, alcohol use, and high–risk cycling. Young offenders at the time of admission (6.61, 2.58–15.2), at 6 months (3.12, 1.81–10.1), and at 12 months (5.29, 1.98–13.3) reported statistically higher levels of total mental health problems than adolescents in a community sample. Conclusions Young offenders have a high rate of mental and behavioral disorders. In the detention period, aggressive behavior, self–destructive/identity, and externalizing of problems improved while withdrawn, anxious or depressed, and internalizing of problems worsened.
Experimental observations of inception cavitation vortices around a hydrofoils
绕水翼初生空化涡的实验观测

Zhang Mindi,Wang Guoyu,Lu Junrui,
张敏弟
,王国玉,鲁君瑞

力学学报 , 2006,
Abstract: The inception cavitation around a 2D-hydrofoil in the boundary layer of a non-separated turbulent flow was studied experimentally. The cavitation inceptions were observed by a high speed video camera, and the velocities around the hydrofoil were measured by a 2D-LDV. It is shown that the inception cavitation bubbles are generated along with a hairpin-shaped vortex coherent structure in the boundary layer of the non-separated turbulent flow. The developing process of an inception cavitation bubble vortice comprises generation, expanding, collapse, rebound and re-collapse. It is concluded that the inception cavitation has dual characteristics of both bubbles and coherent structures.
Application study of the awning measure to obstruct solar radiation in permafrost regions on the Qinghai-Tibet Plateau

WenJie Feng,ZhiZhong Sun,Zhi Wen,GuoYu Li,Ze Zhang,WenBing Yu,

寒旱区科学 , 2012,
Abstract:
Current developments of research on permafrost engineering and cold region environment: a report of the 8th International Symposium on Permafrost Engineering

FuJun Niu,GuoYu Li,ShuPing Zhao,ShuJuan Zhang,YongGuo Zhao,HuiJun Jin,

寒旱区科学 , 2010,
Abstract:
A Study of the Characteristics of the Cluster Extreme Events in China
基于综合气象干旱指数的中国干旱变化趋势研究

Zou Xukai,Ren Guoyu,Zhang Qiang,
邹旭恺
,任国玉,张强

气候与环境研究 , 2010,
Abstract: 基于中国606个地面台站1951~2008年的逐日降水量和气温资料,采用综合气象干旱指数CI统计分析了中国全国及十大江河流域近60年的干旱变化趋势。结果表明,近60年来,从整体来看,中国干旱面积呈现出弱的增加趋势。干旱持续时间长的几个中心分别位于北方的辽河流域西部、黄河流域东部、海河流域、西南诸河流域东南部等地,最长持续时间可达4个月以上;北方江河流域干旱面积一般表现出增加趋势,其中松花江流域、辽河流域、海河流域干旱面积出现显著的增加趋势,辽河流域、海河流域、黄河流域在20世纪90年代中后期至21世纪前期连续数年出现大范围干旱,南方大多数江河流域干旱面积的变化趋势不明显,只有西南诸河流域有显著的减少趋势。
Pseudoginsenoside F11, a Novel Partial PPARγ Agonist, Promotes Adiponectin Oligomerization and Secretion in 3T3-L1 Adipocytes
Guoyu Wu,Junyang Yi,Ling Liu,Pengcheng Wang,Zhijie Zhang,Zhen Li
PPAR Research , 2013, DOI: 10.1155/2013/701017
Abstract: PPARγ is a nuclear hormone receptor that functions as a master regulator of adipocyte differentiation and development. Full PPARγ agonists, such as the thiazolidinediones (TZDs), have been widely used to treat type 2 diabetes. However, they are characterized by undesirable side effects due to their strong agonist activities. Pseudoginsenoside F11 (p-F11) is an ocotillol-type ginsenoside isolated from Panax quinquefolium L. (American ginseng). In this study, we found that p-F11 activates PPARγ with modest adipogenic activity. In addition, p-F11 promotes adiponectin oligomerization and secretion in 3T3-L1 adipocytes. We also found that p-F11 inhibits obesity-linked phosphorylation of PPARγ at Ser-273 by Cdk5. Therefore, p-F11 is a novel partial PPARγ agonist, which might have the potential to be developed as a new PPARγ-targeted therapeutics for type 2 diabetes. 1. Introduction The nuclear hormone receptor PPARγ (peroxisome proliferator-activated receptor γ) is a ligand-activated transcription factor highly expressed in the adipose tissues [1]. By binding to PPARγ-responsive regulatory elements as heterodimers with retinoid X receptor (RXR), PPARγ regulates the expression of networks of genes involved in adipogenesis, lipid metabolism, inflammation, and maintenance of metabolic homeostasis [2]. PPARγ consists of an amino terminal activation domain (AF-1), a highly conserved DNA-binding domain (DBD), and a C-terminal ligand-binding domain (LBD) containing a ligand-dependent transactivation domain (AF-2) [3]. Ligand binding promotes a conformational change which allows for differential recruitment of cofactors and subsequent modulation of PPARγ activity [4, 5]. PPARγ is the pharmacological target of the insulin-sensitizing thiazolidinediones (TZDs) that have been widely used in the treatment of type 2 diabetes. TZDs function as selective PPARγ ligands and induce transcription of PPARγ-targeted genes [6]. Derivatives of TZD, such as rosiglitazone (Avandia) and pioglitazone (Actos), are highly effective in treating type 2 diabetes and are well tolerated by the majority of patients [1]. However, they are associated with various undesirable side effects, including weight gain, fluid retention, edema, congestive heart failure, and bone fracture [7, 8]. Long-term use of TZDs may be associated with increased risk of bladder cancer [9]. These limitations have raised substantial concerns and significantly impaired their future in many countries [10]. Therefore, it is critical to develop TZD substitutes for improved therapies of type 2 diabetes. Studies in animal
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