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Search Results: 1 - 10 of 127088 matches for " Hongjian Li "
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An Improved Non-isolated LED Converter with Power Factor Correction and Average Current Mode Control  [PDF]
Renbo Xu, Hongjian Li, Yongzhi Li, Changqian Zhang
Circuits and Systems (CS) , 2011, DOI: 10.4236/cs.2011.23034
Abstract: A new type of high power LED drivers is proposed by adopting an improved two-stages non-isolated configuration. In order to improve power factor and achieve accurate average current control under universal input voltages ranging from 100 Vrms to 240 Vrms, the power factor correction and average current mode control methods operating in continuous current conduction mode are designed and implemented. With the LUMILEDS emitter type LEDs, a laboratory prototype is built and measured. And from the measured results, it could be concluded that the proposed driver has many better performances such as high power factor, low current harmonic, accurate average current control and switch protection.
Research on a High-Efficiency LED Driving Circuit Based on Buck Topology  [PDF]
Renbo Xu, Hongjian Li, Yongzhi Li, Xiaomao Hou
Circuits and Systems (CS) , 2011, DOI: 10.4236/cs.2011.24048
Abstract: A high efficiency LED(Light Emitting Diode) driver based on Buck converter, which could operate under a wide AC input voltage range(85V~265V) and drive a series of high power LEDs, is presented in this paper. The operation principles, power loss factors of the LED driver in this study are analyzed and discussed in detail and some effective ways to improve efficiency are proposed through system design considerations. To verify the feasibility, a laboratory prototype is also designed and tested for an LED lamp which consists of 16 LUMILEDS LEDs in series. Experimental results show that a high efficiency of 92% at I0=350mA can be achieved and the studied driver might be practical for driving high power LEDs. In the last, the overall efficiency over 90% is gained through some experiments under variable input and output voltages and verifies the validity of the designed driver.
Fractionation and structural identification of antibiotic activity substances from Streptomyces herbaricolor HNS2-2  [PDF]
Lili Chen, Youzhi Li, Hongjian Zhu, Yuhua Liu, Bida Gao
Agricultural Sciences (AS) , 2012, DOI: 10.4236/as.2012.34068
Abstract: Four groups of antibiotic activity compounds were separated and purified from the ethyl acetate fraction of a broth culture of Streptomyces herbaricolor HNS2-2.Trace analyses were performed and anti-microbial activities were determined. The antibiotic activity compounds were identified as quercetin dehydrate ①, p-hydroxyphenyl ②, 4’-hydroxyflavanone ③, and 3-hydroxyflavone ④ based on spectroscopic data. Compounds 1-4 showed significant antimicrobial activities against Staphylococcus aureus and the tobacco mosaic virus in vitro, suggesting their potential agricultural and medical applications.
Alloy Gene Gibbs Energy Partition Function and Equilibrium Holographic Network Phase Diagrams of AuCu-Type Sublattice System  [PDF]
Youqing Xie, Xiaobo Li, Xinbi Liu, Yaozhuang Nie, Hongjian Peng
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2013, DOI: 10.4236/ijcns.2013.610045
Abstract: Taking AuCu-sublattice system as an example, we present two discoveries and a method. First, the alloy gene sequences are the central characteristic atom sequences in the basic coordination cluster sequences. Second, the transmission mode of the information about structures and properties of the alloy genes is described by the alloy gene Gibbs energy partition function. The most valuable method in the system sciences is “the whole obtained from a few parts”. We have established the alloy gene database and holographic alloy positioning system of the Au-Cu system, as well as alloy gene Gibbs energy partition function and equilibrium holographic network phase diagrams of the AuCu-type sublattice system. It means that a standard way for researchers to share predictive algorithms and computational methods may be produced during designing advanced alloys.
Alloy Gene Sequence Project and System Science Philosophy  [PDF]
Youqing Xie, Xiaobo Li, Xinbi Liu, Hongjian Peng, Yaozhuang Nie
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2017, DOI: 10.4236/ijcns.2017.1012019
Abstract: System Science Philosophy is a knowledge system constructed of universal principle and law sequences. Alloy gene is a characteristic atom existing in the center of coordination cluster and occupying the lattice point of a lattice cell, and carries holographic information about valence electron structure, physical and thermodynamic properties obtained by alloy gene theory. Alloy gene potential energy curve function has developed traditional atom pair interaction potential functions into many atoms’ interaction function associated with valence electron structure, bond length, bond energy, which makes alloy gene Gibbs energy function can be established. Alloy gene Gibbs energy transmissive function has developed traditional partition function. Its equilibrium and sub-equilibrium transmissive modes produce alloy holographic network positioning bank, which is operable platform to achieve transformation from “trial and error” method to the “whole obtained from a few part” law for getting advanced alloys. It has become possible to launch alloy gene sequence project.
Laser Induced C60 Cage Opening Studied by Semiclassical Dynamics Simulation
Hong Tang,Hongjian Li,Yusheng Dou
International Journal of Molecular Sciences , 2011, DOI: 10.3390/ijms12010353
Abstract: Laser induced opening of the C 60 cage is studied by a semiclassical electron-radiation-ion dynamics technique. The simulation results indicate that the C 60 cage is abruptly opened immediately after laser excitation. The opening of the C 60 cage induces a quick increase in kinetic energy and a sharp decrease in electronic energy, suggesting that the breaking of the C 60 cage efficiently heats up the cluster and enhances the thermal fragmentation of C 60 fullerene.
Design of a Capacitive Flexible Weighing Sensor for Vehicle WIM System
Lu Cheng,Hongjian Zhang,Qing Li
Sensors , 2007, DOI: 10.3390/s7081530
Abstract: With the development of the Highway Transportation and Business Trade, vehicle weigh-in-motion (WIM) technology has become a key technology and trend of measuring traffic loads. In this paper, a novel capacitive flexible weighing sensor which is light weight, smaller volume and easy to carry was applied in the vehicle WIM system. The dynamic behavior of the sensor is modeled using the Maxwell-Kelvin model because the materials of the sensor are rubbers which belong to viscoelasticity. A signal processing method based on the model is presented to overcome effects of rubber mechanical properties on the dynamic weight signal. The results showed that the measurement error is less than ±10%. All the theoretic analysis and numerical results demonstrated that appliance of this system to weigh in motion is feasible and convenient for traffic inspection.
Structure dependence of intramolecular photoinduced electron transfer in 9-aminoacridine benzoyl esters dyads linked by a polyether chain
Shunlai Li,Hongjian Tian,Qingfu Zhou,Zonghe Li,Huijun Xu
Chinese Science Bulletin , 1997, DOI: 10.1007/BF02882571
Abstract: Both experimental observations and theoretical calculations indicated that: (I) The flexible dyads reported in this paper exist preferentially in folded conformations in which the donor and the acceptor are held in close proximity. This allows overlap of the orbitals of each moiety leading to very efficient intramolecular fluorescence quenching. (ii) Quenching of the fluorescence of the donor in the dyads via electron transfer depends on the electron affinity of the acceptor. (iii) The electron-attracting ability of the acceptors in the dyads is strongly influenced by the type and relative spatial disposition of the substituents.
Low temperature thermodynamic study of the stable and metastable phases of vanadium
XiaoBo Li,YouQing Xie,YaoZhuang Nie,HongJian Peng
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0471-y
Abstract: The low temperature thermodynamics of the stable phase of vanadium has been assessed by the polynomial and Debye models from the experimental data available in literature. By means of the constrained nonlinear least squares curve fitting arithmetic, two sets of parameter values have been determined. Expressions of the thermodynamic functions C p(T) and G(T)-H (298.15 K) at 0–298.15 K are presented. The low temperature thermodynamics of the metastable phase of vanadium can only be extrapolated by the Debye model. The expression of the thermodynamic function C p(T) at 0–298.15 K is presented.
Statistics and Analysis about the Research of Knowledge Rights Protection

Gu Xiaohua Li Hongjian,

现代图书情报技术 , 1999,
Abstract: This paper is a statistics about research of the knowledge righte protection under environment of network in our country for five years, and analyze the dates about its process, recent situation and developmental trend. These will be helpful for our country s network construct and the research of the knowledge rights protection under environment of network.
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