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Search Results: 1 - 10 of 49412 matches for " LEI Jun "
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Empirical Research on the Relationship between Scientific Innovation and Economic Growth in Beijing  [PDF]
Lei Zhang, Wei Song, Jun He
Technology and Investment (TI) , 2012, DOI: 10.4236/ti.2012.33023
Abstract: This paper will build up a model about the dynamic relationship between scientific innovation and economic growth in Beijing, with VAR model (Vector Autoregressive Model), and choose the quantity of patent applications, sum of business transactions in the market of technologies and the foreign direct investment as its indicators of science and technology output, GDP as its indicator of economic growth, which finally uses variance decomposition analysis. The research shows that there is a long-term equilibrium relationship between scientific innovation and economic growth, and both have interactivity which means that scientific innovation promotes economic growth and economic growth boosts the scientific innovation.
Implication of heme oxygenase-1 in the sensitivity of nasopharyngeal carcinomas to radiotherapy
Lei Shi, Jun Fang
Journal of Experimental & Clinical Cancer Research , 2008, DOI: 10.1186/1756-9966-27-13
Abstract: Heme oxygenase (HO) catalyzes the rate-limiting step of heme degradation, leading to formation of biliverdin, carbon monoxide (CO), and free iron [1,2], which play crucial roles in the adaptation to and/or defense against oxidative stress and cellular stress. HO-1 is a member of the hear shock protein family (HSP-32), and its expression is triggered by diverse stress-inducing stimuli including hypoxia [3], heavy metals [4], UV irradiation [5], reactive oxygen species (ROS) and reactive nitrogen species [5-7]. It is believed that induction of HO-1 protects cells from these toxic stimuli by multiple mechanisms: (a) decreasing the prooxidant level (heme) [8]; (b) increasing the antioxidant level (bilirubin) [9]; (c) producing the antiapoptotic molecule CO [10]; (d) inducing ferritin, which removes and detoxifies free ferric ion [11]; (e) preventing overstimulation of the immune response [12]. Indeed, inhibition of HO-1 by using specific HO inhibitors such as zinc protoporphyrin or tin protoporphyrin extended the pathological consequences of disorders involving these stress-inducing stimuli: graft rejection [13], ischemia-reperfusion injury [14], cisplatin nephrotoxicity [15], and endotoxin-induced septic shock [12]. In contrast, HO-1 inducers such as cobalt protoporphyrin had beneficial effects on certain diseases [14,16].More important, it is now well known that expression of high levels of HO-1 occurs in various tumors [17], and that HO-1 has an important role in rapid tumor growth because of its antioxidative and antiapoptotic effects [17]. HO-1 was thus considered to be a key molecule for tumors against the attack from the host and chemotherapy and radiotherapy by protecting tumor cells from oxidative insults. It is interesting to note that several tumors, including renal cell carcinoma [18] and prostate tumors [19] in human, express a high level of HO-1. However, very little is known concerning the relationship of HO-1 expression and clinical features in nasophary
Trend of urban system structure under the restriction of water and land resources in Xinjiang
Xiaolei Zhang,Jun Lei
Chinese Science Bulletin , 2006, DOI: 10.1007/s11434-006-8224-x
Abstract: On the basis of studies on water and land resources affecting urban development and urban system structure in Xinjiang, this paper analyzes the utilization status and shortage of urban water resources. It is considered that both the consumption and waste of urban water resources are in an increase trend. Most cities and towns in Xinjiang are in shortage of water resources, however, waste of water resources are serious, especially in small towns. The development of the megapolis and moderate cities is evidently restricted by limited land resources. Though there are relatively large spaces of expanding the small cities and towns, the output benefits of water and land resources are low. In order to achieve the ordinal expansion of urban system structure in Xinjiang, it is suggested to take the urban spatial development pattern of “one circle and three belts” and the resources-economized strategy in the rapid development of urbanization.
Finite State Machine Detection Model Based on Adaptive TTL Neuron
Zhang Jun,Gao Lei
Journal of Applied Sciences , 2006,
Abstract: Without detailed knowledge of the network topology between Network Security Audit System (NSAS) and the end system, NSAS may be unable to determine whether a given packet will even be seen by the end system. Finite state machine detection model based on adaptive TTL neuron is proposed to solve it in this paper. By inspecting the variance of Time To Live (TTL) field in ingress sequence, the adaptive TTL neuron compares the TTL field of new fragment with the average to detect whether the TTL field of new fragment is normal or not. Combining the TTL neuron with the detection state node of finite state machine detection model, ingress flow will be benign and NSAS won`t be confused anymore.
A Study of Safety Evaluation Method for Medical Diagnostic Table  [PDF]
Xiaoyan Zhang, Jia Liu, Jun Guo, Lei Feng
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.510B044
Abstract:

Medical diagnostic tables are widely used inthemedical diagnostic equipment. For multifarious diagnostic needs, the medical diagnostic table works in various operating modes. In order to ensure patient safety, safety factor of medical diagnostic table must meet safety requirement. The paper puts forward a method to find relations between key parameters and stress of table, identify maximum stress modes, reduce modes number of load test, and remove conservative high stress areas from finite element analysis result, by synthesizingthestress result of finite element analysis and measurement data for various operating modes of medical diagnostic table. It will help shorten test time, avoid over strength design, and reduce table’s cost. An application example of the method is presented by evaluating a specific CT medical diagnostictable. This method can be a reference for safety evaluation of all medical diagnostic tables.

Insights into Ecological Effects of Invasive Plants on Soil Nitrogen Cycles  [PDF]
Congyan Wang, Hongguang Xiao, Jun Liu, Lei Wang, Daolin Du
American Journal of Plant Sciences (AJPS) , 2015, DOI: 10.4236/ajps.2015.61005
Abstract: The increasing degree of plant invasion is an expanding problem that affects the functioning and composition of forest ecosystems with increasing anthropogenic activities, particularly soil nitrogen (N) cycles. Numerous studies have revealed that one of the main factors for successful plant invasion is that plants could pose significant effects on soil N cycles via direct and/or indirect ways, such as changes in soil microbial communities, litter decomposition rates, and/or soil physicochemical properties. We thereby summarize the ecological effects of invasive plants on soil N cycles, including the aforementioned changes, to understand the mechanism of successful invasion. We also discuss the needs for further research on the relationship between invasive plants and soil N cycles.
A Semi-Implicit Scheme of Lattice Boltzmann Method for Two Dimensional Cavity Flow Simulation  [PDF]
Lei Zhang, Jun Yao, Hai Sun, Jianguang Zhang
Open Journal of Fluid Dynamics (OJFD) , 2015, DOI: 10.4236/ojfd.2015.51002
Abstract: The calculation sequence of collision, propagation and macroscopic variables is not very clear in lattice Boltzmann method (LBM) code implementation. According to the definition, three steps should be computed on all nodes respectively, which mean three loops are needed. While the “pull” scheme makes the only one loop possible for coding, this is called semi-implicit scheme in this study. The accuracy and efficiency of semi-implicit scheme are discussed in detail through the simulation of lid-driven cavity flow. Non-equilibrium extrapolation scheme is adopted on the boundary of simulation area. The results are compared with two classic articles, which show that semi-implicit scheme has good agreement with the classic scheme. When Re is less than 3000, the iterations steps of semi-scheme can be decreased by about 30% though comparing the semi-implicit scheme with standard scheme containing three loops. As the Re increases into more than 3400, the standard scheme is not converged. On the contrary, the iterations of semi-implicit scheme are approximately linear to Re.
Interface dipole induced by asymmetric exchange effect in Mott-insulator/Mott-insulator heterojunction

Hao Lei,Wang Jun,

中国物理 B , 2008,
Abstract: We study theoretically the interfacial electronic property of a heterojunction made from two Mott insulators (MI) with different magnetic structures. By means of unrestricted Hartree-Fock calculations in real space, we find that a charge dipole can form spontaneously near the interface of the MI/MI heterojunction. The magnitude of this charge dipole depends strongly on the magnetic states of both sides of the heterojunction. Combining with the result from an exactly solvable two-site toy model, we argue that the interface dipole arises from exchange effects as well as its asymmetry intrinsic to the heterojunction near the interface. Our study may shed light on the fabrication of ultrathin ferroelectric and magnetoelectric devices.
Predicting Gene Expression from Sequence: A Reexamination
Yuan Yuan,Lei Guo,Lei Shen,Jun S Liu
PLOS Computational Biology , 2007, DOI: 10.1371/journal.pcbi.0030243
Abstract: Although much of the information regarding genes' expressions is encoded in the genome, deciphering such information has been very challenging. We reexamined Beer and Tavazoie's (BT) approach to predict mRNA expression patterns of 2,587 genes in Saccharomyces cerevisiae from the information in their respective promoter sequences. Instead of fitting complex Bayesian network models, we trained na?ve Bayes classifiers using only the sequence-motif matching scores provided by BT. Our simple models correctly predict expression patterns for 79% of the genes, based on the same criterion and the same cross-validation (CV) procedure as BT, which compares favorably to the 73% accuracy of BT. The fact that our approach did not use position and orientation information of the predicted binding sites but achieved a higher prediction accuracy, motivated us to investigate a few biological predictions made by BT. We found that some of their predictions, especially those related to motif orientations and positions, are at best circumstantial. For example, the combinatorial rules suggested by BT for the PAC and RRPE motifs are not unique to the cluster of genes from which the predictive model was inferred, and there are simpler rules that are statistically more significant than BT's ones. We also show that CV procedure used by BT to estimate their method's prediction accuracy is inappropriate and may have overestimated the prediction accuracy by about 10%.
(Cyclohexanecarboxylato)bis(di-2-pyridylamine)zinc(II) nitrate monohydrate
Ying-Jie Cai,Jun Yang,Peng Huang,Lei Lei
Acta Crystallographica Section E , 2009, DOI: 10.1107/s1600536809033443
Abstract: In the title compound, [Zn(C7H11O2)(C10H9N3)2]NO3·H2O, the ZnII atom is five-coordinated by two bidentate di-2-pyridylamine ligands and one O atom from a cyclohexanecarboxyate anion, resulting in a ZnON4 square-based pyramidal coordination for the metal ion with the O atom in one of the basal positions. In the crystal, the components interact by way of O—H...O, O—H...N and N—H...O hydrogen bonds.
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