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      • KCI등재

        A Novel Distributed Equivalent Circuit Model for Single-Core Cables

        Li Rui-Fang,Hu Hao,Cao Xiao-Bin,Li Zhong-Mei,Li Jun-Hao,Zhu Chuan-Lin,Liu Le-Jia 대한전기학회 2024 Journal of Electrical Engineering & Technology Vol.19 No.1

        The number of cables used for urban power supply increases rapidly. The sheath current in these cables, which is generated via induction, produces a current loss. When the situation is serious, the ground lead and the middle connector of the cable will be burned. In this paper, the existing single-core cable equivalent circuit model is used to calculate the sheath current of a 3-phase cable under the condition of non-transposition and cross connection. By comparing the calculated results with the simulation and the experimental results, it is found that the current distribution law for the sheath, which was obtained using the existing model, difers substantially from both the simulation and actual measurements. The error reason of the existing model is revealed, and it is found that the magnitude and phase of the current in the metal sheath of the cable varies with the position under the combined efect of distributed capacitances in the cable and the core-current fux, especially for a 3-phase cross connection, each section of the cable does not meet Kirchhof’s laws, but the sheath electric current in the existing models are considered equal everywhere. Therefore, a novel cable equivalent model is proposed in this paper, which is based on a distributed circuit, and an equation to calculate the sheath current is derived. The model presented in this paper corrects the problems of the existing model, which can be applied to power system, subway, high-speed rail, and any application of single-core cables.

      • KCI등재

        Proanthocyanidins accelerate the germination of cucumber (Cucumis sativus L.) seeds

        Li-jun Zhu,Xing-guang Deng,Li-juan Zou,Jun-qiang Wu,Da-wei Zhang,Honghui Lin 한국식물학회 2016 Journal of Plant Biology Vol.59 No.2

        Proanthocyanidins (PAs) are the end products of the flavonoid biosynthetic pathway in many seeds, but their biological function is rarely unknown during seed germination. In the present study, we observed that PAs pretreatment accelerated cucumber seeds germination with maximum efficiency at 0.15% by measuring germination percentage and radical length. Using inhibitors of abscisic acid (ABA), gibberellins (GA) and alternative oxidase (AOX) and H2O2 scavenger pretreatment and gene expression analysis, we found that the accelerated effect of 0.15% PAs on seed germination was due to the decreased ABA biogenesis and enhanced GA production. ROS are induced by PAs pretreatment. Then, the enhanced ROS contributed to GA and ethylene accumulation and ABA decrease in seeds. Moreover, the improvement of GA was involved in the further induction of antioxidant enzymes activities. Therefore, our findings uncover a novel role of PAs in seed germination and clarify the relationships between ROS, ABA, GA and ethylene during seed germination.

      • KCI등재

        Magnetic Field Calculation and Multi-objective Optimization of Axial Flux Permanent Magnet Generator with Coreless Stator Windings

        Zhu Jun,Li Shaolong,Song Dandan,Han Qiaoli,Li guanghua 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.4

        For the problem that the complexity of 3-D modeling and multi parameter optimization, as well as the uncertainty of the winding factor of axial flux permanent magnet generator with coreless windings. The complex 3-D model was simplified into 2-D analytic model, and an analytical formula for the winding factor that adapting different coreless stator winding is proposed in this paper. The analytical solution for air-gap magnetic fields, no-load back EMF, electromagnetic torque, and efficiency are calculated by using this method. The multiple objective and multivariable optimization of the maximum fundamental and the minimum harmonic content of back EMF are performed by using response surface methodology. The proposed optimum design method was applied to make a generator. The generator was tested and the calculated results are compared with the proposed method, which show good agreements.

      • Impact of a Clinical Pathway on Hospital Costs, Length of Stay and Early Outcomes after Hepatectomy for Hepatocellular Carcinoma

        Zhu, Liang,Li, Jun,Li, Xiao-Kang,Feng, Jun-Qiang,Gao, Jian-Min Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.13

        Background: A clinical pathway (CP) can standardize and improve perioperative care for a number of interventions. In hepatic surgery, however, pertinent evidence is very limited. This study was conducted to implement a CP for hepatocellular carcinoma (HCC) patients undergoing hepatectomy, and to evaluate its effects on hospital costs, length of hospital stay (LOHS) and early clinical outcomes. Materials and Methods: Medical records for HCC patients undergoing hepatectomy were retrospectively reviewed before implementation of a CP (the non-CP group) from March 2012 to August 2012. This information was compared with the data collected prospectively from patients after implementation of the CP (the CP group) between September 2012 and April 2013. Hospital costs, LOHS and early clinical outcomes were evaluated and compared between groups. Results: There were no significant differences in terms of patient clinical characteristics between the two groups. For clinical outcome measures, no significant differences were found in postoperative complications, mortality and readmission rate. The hospital costs were significantly reduced from 24,844 RMB in the non-CP group to 19,761 RMB in the CP group (p<0.01). In addition, patients of the CP group also had shorter LOHS compared with the non-CP group (8.3 versus 12.3 days, p<0.001). Conclusions: The CP proved to be an effective approach to minimize hospital costs and LOHS with hepatectomy for HCC without compromising patient care.

      • KCI등재

        Comparative Analysis of Coreless Axial Flux Permanent Magnet Synchronous Generator for Wind Power Generation

        Zhu Jun,Li Guanghua,Cao Di,Zhang Zhenyi,Li Shuaihui 대한전기학회 2020 Journal of Electrical Engineering & Technology Vol.15 No.2

        A 90° Halbach permanent magnet array coreless axial fux permanent magnet synchronous generator for wind power generation is compared with a conventional axial fux permanent magnet generator with cut cake type permanent magnet. 2D analytic model of generator is established. The air gap magnetic felds of two generators are analyzed by analytical method, and the air gap magnetic density and harmonic content are analyzed. Then the infuence of diferent parameters on voltage total harmonic distortion is analyzed by changing the pole arc coefcient, air gap length, permanent magnet thickness and number of turns. Two prototypes of generators are manufactured, and the correctness of the simulation results is verifed by experiments.

      • KCI등재

        Microstructures and nano mechanical properties of the metal tungsten film

        Zhu Li-na,Li Guo-lu,Wang Hai-dou,Xu Bin-shi,Zhuang Da-ming,Liu Jia-jun 한국물리학회 2009 Current Applied Physics Vol.9 No.3

        The W film was prepared on 1045 steel by magnetron sputtering, with the thickness of 2 ㎛, its surface and cross-section morphologies were investigated with SEM, and the phase structure was analyzed with XRD. X-ray stress determinator was utilized to measure its residual stress, and the nano-hardness and elastic modulus of the film were surveyed by nano-indentation tester. The results show that the surface of W film is very compact and smooth; the particles arranged regularly, the granularity of the thin film is about 1 ㎛. The microcracks, cavities and desquamation were not found in the film and interface, and the bonding between the W film and substrate is well. The XRD results showed that the W film had a body-centered cubic structure, the lattice constant: ɑ = 0.316 nm, the growth preferred orientations are (110) and (220). The compressive stress (-169 MPa) was found on the surface. The average nano-hardness and elastic modulus of W film are 15.22 GPa, 176.64 GPa, respectively, and the mechanical properties of W film are well. The W film was prepared on 1045 steel by magnetron sputtering, with the thickness of 2 ㎛, its surface and cross-section morphologies were investigated with SEM, and the phase structure was analyzed with XRD. X-ray stress determinator was utilized to measure its residual stress, and the nano-hardness and elastic modulus of the film were surveyed by nano-indentation tester. The results show that the surface of W film is very compact and smooth; the particles arranged regularly, the granularity of the thin film is about 1 ㎛. The microcracks, cavities and desquamation were not found in the film and interface, and the bonding between the W film and substrate is well. The XRD results showed that the W film had a body-centered cubic structure, the lattice constant: ɑ = 0.316 nm, the growth preferred orientations are (110) and (220). The compressive stress (-169 MPa) was found on the surface. The average nano-hardness and elastic modulus of W film are 15.22 GPa, 176.64 GPa, respectively, and the mechanical properties of W film are well.

      • SCIESCOPUS

        An eigenspace projection clustering method for structural damage detection

        Zhu, Jun-Hua,Yu, Ling,Yu, Li-Li Techno-Press 2012 Structural Engineering and Mechanics, An Int'l Jou Vol.44 No.2

        An eigenspace projection clustering method is proposed for structural damage detection by combining projection algorithm and fuzzy clustering technique. The integrated procedure includes data selection, data normalization, projection, damage feature extraction, and clustering algorithm to structural damage assessment. The frequency response functions (FRFs) of the healthy and the damaged structure are used as initial data, median values of the projections are considered as damage features, and the fuzzy c-means (FCM) algorithm are used to categorize these features. The performance of the proposed method has been validated using a three-story frame structure built and tested by Los Alamos National Laboratory, USA. Two projection algorithms, namely principal component analysis (PCA) and kernel principal component analysis (KPCA), are compared for better extraction of damage features, further six kinds of distances adopted in FCM process are studied and discussed. The illustrated results reveal that the distance selection depends on the distribution of features. For the optimal choice of projections, it is recommended that the Cosine distance is used for the PCA while the Seuclidean distance and the Cityblock distance suitably used for the KPCA. The PCA method is recommended when a large amount of data need to be processed due to its higher correct decisions and less computational costs.

      • KCI등재

        Celastrol, produced by Tripterygium wilfordii Hook F. enhances defense response in cucumber seedlings against diverse environmental stresses

        Li-jun Zhu,Xing-guang Deng,Li-juan Zou,Peng-xu Li,Jun-qiang Wu,Da-wei Zhang,Honghui Lin 한국식물학회 2017 Journal of Plant Biology Vol.60 No.1

        Celastrol is an active triterpenoid compound isolated from Tripterygium wilfordii Hook F.. Many reports have highlighted that celastrol is an effective, safe and desirable approach to the treatment of cancers. However, their biological function during environmental stresses in plants is rarely reported. In the present study, the effects of celastrol on the tolerance against high light (HL), polyethylene glycol (PEG) and cold stress in cucumber (Cucumis sativus L.) were investigated. Celastrol pretreatment could enhance cucumber seedlings stress tolerance at a concentration of 1 μg ml–1. The results showed that pretreatment with 1 μg ml–1 celastrol clearly induced the activities of antioxidative enzymes, which subsequently alleviated stress-induced oxidative damage in plant cells. We also provided evidence that celastrol upregulated ABA biosynthetic gene NCED2 expression and ABA accumulation in cucumber seedlings, which resulted to the enhanced tolerance in response to environmental stresses. Furthermore, the celastrol-pretreated seedlings showed less photosystem damaged caused by the stress conditions, when compared with the control. Therefore, our findings provide a novel role of celastrol in plant against environmental stresses and indicate that the celastrol-induced activities of antioxidative enzymes and ABA content might contribute to the stress tolerance.

      • KCI등재

        Effects of rehydration on physiological and transcriptional responses of a water-stressed rhizobium

        Zhu Jie,Jiang Xin,Guan Dawei,Kang Yaowei,Li Li,Cao Fengming,Zhao Baisuo,Ma Mingchao,Zhao Ji,Li Jun 한국미생물학회 2022 The journal of microbiology Vol.60 No.1

        As a microsymbiont of soybean, Bradyrhizobium japonicum plays an important role in symbiotic nitrogen fixation and sustainable agriculture. However, the survival of B. japonicum cells under water-deplete (e.g., drought) and water-replete (e.g., flood) conditions is a major concern affecting their nitrogen-fixing ability by establishing the symbiotic relationship with the host. In this study, we isolated a water stress tolerant rhizobium from soybean root nodules and tested its survival under water-deplete conditions. The rhizobium was identified as Bradyrhizobium japonicum and named strain 5038. Interestingly, both plate counting and live/dead fluorescence staining assays indicate that a number of viable but non-culturable cells exist in the culture medium upon the rehydration process which could cause dilution stress. Bradyrhizobium japonicum 5038 cells increased production of exopolysaccharide (EPS) and trehalose when dehydrated, suggesting that protective responses were stimulated. As expected, cells reduced their production upon the subsequent rehydration. To examine differential gene expression of B. japonicum 5038 when exposed to water-deplete and subsequent waterreplete conditions, whole-genome transcriptional analysis was performed under 10% relative humidity (RH), and subsequent 100% RH, respectively. A total of 462 differentially expressed genes (DEGs, > 2.0-fold) were identified under the 10% RH condition, while 3,776 genes showed differential expression during the subsequent rehydration (100% RH) process. Genes involved in signal transduction, inorganic ion transport, energy production and metabolisms of carbohydrates, amino acids, and lipids were far more up-regulated than downregulated in the 10% RH condition. Notably, trehalose biosynthetic genes (otsAB, treS, and treYZ), genes ligD, oprB, and a sigma factor rpoH were significantly induced by 10% RH. Under the subsequent 100% RH condition, genes involved in transcription, translation, cell membrane regulation, replication and repair, and protein processing were highly up-regulated. Interestingly, most of 10%-RH inducible genes displayed rehydration-repressed, except three genes encoding heat shock (Hsp20) proteins. Therefore, this study provides molecular evidence for the switch of gene expression of B. japonicum cells when encountered the opposite water availability from water-deplete to water-replete conditions.

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