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Zhifang Wang,Changlu Wang,Fengjuan Li,Zhenjing Li,Mianhua Chen,Yurong Wang,Xi Qiao,Hong Zhang 한국미생물학회 2013 The journal of microbiology Vol.51 No.4
The fumigant activity of volatiles generated by Streptomyces alboflavus TD-1 against Fusarium moniliforme Sheldon was investigated. The results showed that the mycelial growth,sporulation, and spore germination of F. moniliforme were significantly suppressed, and that membrane permeability was disrupted in the presence of the volatiles. Gas chromatography-mass Spectrometry analysis revealed 31 kinds of volatile organic compound from the volatiles. Among them,two earthy-smelling substances, namely, 2-methylisoborneol (50.97%) and trans-1,10-dimethyl-trans-9-decalinol (3.10%)were found. The most abundant compound, 2-methylisoborneol,exhibited inhibitory activity against F. moniliforme by fumigation. All these results suggested that S. alboflavus TD-1 can be a promising starter for the inhibition of F. moniliforme through fumigant action.
Analysis on Self-breakdown Statistics Properties for a Spark Switch
Mo, Chen,Guofu, Li,Qinxiao, Dong,Zhifang, Liu,Zhiyuan, Li 대한전기학회 2014 The Journal of International Council on Electrical Vol.4 No.2
According to the working characteristics of over-voltage protective device for series compensation, the principle and structure of spark switch were introduced in this paper briefly. Special test loop and HV fast switch-off device were designed to evaluate the performance of spark swich in trials. Test data and mathematic statistic results revealed that the self-breakdown probability of spark switch obeyed the normal distribution and the cumulative distribution of spark switch self-breakdown had been less affected by different enviroment temperature. The number of trials was restricted to the characteristics of insulated gas and the electrode surface state in the practical application. Reasonable choice of test number can keep estimation error at a relatively low level, particularly for parameter estimation by using small sample of self-breakdown voltage. The conclusion is instructive to the development and engineering application of spark switch for over-voltage protective equipment of series compensation.
Promoter Analysis of Bombyx mori Nucleopolyhedrovirus Ubiquitin Gene
Xu’ai Lin,Yin Chen,Yongzhu Yi,Jie Yan,Zhifang Zhang 한국미생물학회 2008 The journal of microbiology Vol.46 No.4
The aim of this study was to analyze the characteristics of Bombyx mori nucleopolyhedrovirus (BmNPV) ubiquitin gene promoter and the effects of conserved motifs, such as TAAG, TATA, and CAAT, along with baculovirus enhancer homologous region 3 (hr3), on promoter activity. Ubiquitin gene of BmNPV was expressed during the late phase of virus infection. In the presence of viral factors, significant reduction of promoter activity was observed by deletion of -382 to -124 bp upstream of ATG. The fragment between -187 and -383 bp upstream of ATG, including distal TAAG, CAAT motif, and TATA box, could also drive expression of the reporter gene. The mutation of cis-elements TATA boxes and TAAG motifs significantly decreased the promoter’s activity, while CAAT mutations enhanced promoter activity by 2- or 3-fold, as compared with the native promoter. In the presence of BmNPV, hr3, both located downstream of the reporter gene of the same vector, and separate vector, could significantly enhance transcription activity of ubiquitin promoter as compared to the control. We concluded that BmNPV ubiquitin gene might be regulated by dual sets of promoter elements, where TAAG and TATA box may positively regulate the expression of ubiquitin, while CAAT motif functions as a negative regulator. Viral factor(s) play an important role in the co-activation of hr3 and promoter.
Xu Yanping,Wang Chen,Yuan Weiwen,Li Zhifang,Yin Zhonggang 대한전기학회 2023 Journal of Electrical Engineering & Technology Vol.18 No.4
In the position sensorless control of permanent magnet synchronous motor (PMSM), the traditional sliding mode observer (SMO) uses the switching function, which presents serious chattering. Otherwise, the traditional SMO uses a low-pass filter to filter the harmonic components in the estimated back-EMF. The low-pass filter usually causes phase delay in the estimated rotor position. These problems restrict the further development of SMO. In this paper, an improved sliding mode observer (ISMO) with suppressed chattering and no phase delay is studied. In the ISMO, a sine saturation function is designed as the control function, and a synchronous reference frame filter (SRFF) is designed to eliminate the phase delay of ISMO. Different from other filters, the SRFF can not only filter out the harmonic components in the estimated back-EMF, but also effectively makes the phase delay almost zero. In addition, in order to improve the poor anti-disturbance performance of position sensorless control, a load disturbance observer (LDO) is introduced on the basis of the ISMO. The experimental results prove the effectiveness of the ISMO, and the addition of LDO improves the anti-disturbance ability of the system.
Sui Guanghui,Cheng Yanyan,Chen Kai,Huang Zhifang,Luo MingHong 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.3
Biomass tar is a by-product generated during biomass gasifi cation. Because of the toxic and harmful nature of biomass tar, its treatment method has become the concern of environmental protection fi eld and related researchers. In this paper, biomass tar was separated into the heavy tar and the phenol-containing liquor after enrichment. Porous carbon (PCs) was prepared using the heavy tar by one-step carbonization activation. The results show that PC_3 has the highest specifi c surface area of 352 m 2 g −1 and mesoporosity ratio of 56.25%. The as-prepared electrode displayed an excellent electrochemical performance for portable super-capacitors, which is a volumetric capacitance of 349 F cm −3 . Assembled super-capacitors have an energy density of 21.65 Wh kg −1 at a power density of 123 W kg −1 . The bio-resins were modifi ed with the phenolcontaining liquor. The results showed that the thermal stability of modifi ed resins had been improved and the structure did not change signifi cantly. This research provides an environmentally friendly and comprehensive utilisation methods for the utilisation of biomass tar.
A Bayesian Network Approach to Launch Vehicle Software Failure Prediction
Tinggui Yan,Xiaoqian Chen,Shipeng Li,Li Ma,Jian Bai,Zhifang Yang 보안공학연구지원센터 2016 International Journal of Multimedia and Ubiquitous Vol.11 No.11
Launch Vehicle software has played an important role in Launch Vehicle system. However, the reliability assessment of Launch Vehicle software is still a hard problem due to the complexity of Launch Vehicle software. Failure prediction can be an effective approach of Launch Vehicle reliability evaluation, whereas failure prediction of software has not yet been fully explored. In this paper, a Markov Bayesian Network model for Launch Vehicle software failure prediction (MBNG) is proposed. In MBNG, unique features of Launch Vehicle software is considered as an important part in the modeling process, which improves the effectiveness of this novel model. Experiments are conducted to verify the effectiveness of MBNG model and compare its performance with classic models.
Deng, Weidong,Wanapat, Metha,Ma, Songcheng,Chen, Jing,Xi, Dongmei,He, Tianbao,Yang, Zhifang,Mao, Huaming Asian Australasian Association of Animal Productio 2007 Animal Bioscience Vol.20 No.7
Six male Gayal (Bos frontalis), approximately two years of age and with a mean live weight of $203{\pm}17$ kg ($mean{\pm}standard\;deviation$), were housed indoors in metabolism cages and fed bamboo (Sinarundinaria) leaves and twigs. After an adjustment period of 24 days of feeding the diet, samples of rumen liquor were obtained for analyses of bacteria in the liquor. The diversity of rumen bacteria was investigated by constructing a 16S rDNA clone library. A total of 147 clones, comprising nearly full length sequences (with a mean length of 1.5 kb) were sequenced and submitted to an on-line similarity search and phylogenetic analysis. Using the criterion of 97% or greater similarity with the sequences of known bacteria, 17 clones were identified as Ruminococcus albus, Butyrivibrio fibrosolvens, Quinella ovalis, Clostridium symbiosium, Succiniclasticum ruminis, Selenomonas ruminantium and Allisonella histaminiformans, respectively. A further 22 clones shared similarity ranging from 90-97% with known bacteria but the similarity in sequences for the remaining 109 clones was less than 90% of those of known bacteria. Using a phylogenetic analysis it was found that the majority of the clones identified (57.1%) were located in the low G+C subdivision, with most of the remainder (42.2% of clones) located in the Cytophage-Flexibacter-Bacteroides (CFB) phylum and one clone (0.7%) was identified as a Spirochaete. It was apparent that Gayal have a large and diverse range of bacteria in the rumen liquor which differ from those of cattle and other ruminants. This may explain the greater live weights of Gayal, compared to cattle, grazing in the harsh natural environments in which Gayal are located naturally.
Zero-Voltage and Zero-Current Switching Interleaved Two-Switch Forward Converter
Enhui Chu,Jianqun Bao,Qi Song,Yang Zhang,Haolin Xie,Zhifang Chen,Yue Zhou 전력전자학회 2019 JOURNAL OF POWER ELECTRONICS Vol.19 No.6
In this paper, a novel zero-voltage and zero-current switching (ZVZCS) interleaved two switch forward converter is proposed. By using a coupled-inductor-type smoothing filter, a snubber capacitor, the parallel capacitance of the leading switches and the transformer parasitic inductance, the proposed converter can realize soft-switching for the main power switches. This converter can effectively reduce the primary circulating current loss by using the coupled inductor and the snubber capacitor. Furthermore, this converter can reduce the reverse recovery loss, parasitic ringing and transient voltage stress in the secondary rectifier diodes caused by the leakage inductors of the transformer and the coupled inductance. The operation principle and steady state characteristics of the converter are analyzed according to the equivalent circuits in different operation modes. The practical effectiveness of the proposed converter was is illustrated by simulation and experimental results via a 500W, 100 kHz prototype using the power MOSFET.