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      • KCI등재

        Chemical composition and in vitro digestibility of corn stover during field exposure and the fermentation characteristics of silage prepared with microbial additives

        Jun Lei Gao,Peng Wang,Chang-Hai Zhou,Ping Li,Hong Yu Tang,Jiabao Zhang,Yimin Cai 아세아·태평양축산학회 2019 Animal Bioscience Vol.32 No.12

        Objective: To effectively use corn stover resources as animal feed, we explored the chemical composition and in vitro digestibility of corn stover during field exposure and the fermentation characteristics of silage prepared with lactic acid bacteria (LAB) and cellulase. Methods: Corn ears including the cobs and shucks were harvested at the ripe stage. The corn stover was exposed in the field under natural weather conditions. Silages were prepared after 0, 2, 4, 7, 15, 30, and 60 d of exposure. Corn stover was chopped into approximately 1 to 2 cm lengths and then packed into 5 liter plastic silos. The ensiling density was 550.1±20.0 g/L of fresh matter, and the silos were kept at room temperature (10°C to 25°C). Silage treatments were designed as follows: without additives (control), with LAB, with cellulase, and with LAB+ cellulase. After 45 d of fermentation, the silos were opened for chemical composition, fermentation quality and in vitro digestion analyses. Results: After harvest, corn stover contained 78.19% moisture, 9.01% crude protein (CP) and 64.54% neutral detergent fiber (NDF) on a dry matter (DM) basis. During field exposure, the DM, NDF, and acid detergent fiber (ADF) contents of corn stover increased, whereas the CP and water-soluble carbohydrate contents and in vitro digestibility of the DM and CP decreased (p<0.05). Compared to the control silage, cellulase-treated silage had lower (p<0.05) NDF and ADF contents. The pH values were lower in silage treated with LAB, cellulase, or LAB+cellulase, and lactic acid contents were higher (p<0.05) than those of the control. Silage treated with cellulase or LAB+cellulase improved (p<0.05) the in vitro DM digestibility (IVDMD) compared to that of the control or LAB-treated silage. Conclusion: Corn stover silage should be prepared using fresh materials since stover nutrients are lost during field exposure, and LAB and cellulase can improve silage fermentation and IVDMD.

      • KCI등재

        Spin reorientation of Fe films studied by the magneto-optical Kerr effect

        Jun Ye,Qing-Yuan Jin,Bin Ma,Chun-Lei Gao,Yuan Zhao 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.44 No.32

        The ability to alter magnetic anisotropy values is of technological importance in the application of magnetic ultrahigh-density recording. By capping some other atoms onto the surface of a magnetic thin lm or inserting a thin layer between the magnetic lm and the substrate, we can change the surface or interface perpendicular magnetic anisotropy and then alter the magnetic properties of the lm, such as the spin reorientation transition (SRT), in ultrathin ferromagnetic lms. The SRT of face-centered-tetragonal (fct) Fe lms grown on Cu(001) substrate is determined by the magneto-optical Kerr eect. We nd that the out-of-plane magnetization changes to in-plane induced by a Ni-capping or a Co-inserting layer at 110 K. From the linear relation of the critical thickness of a fct-Fe lm with Ni or Co covering when SRT occurs, the \true" critical thickness of the pure fct-Fe lm without coverage or buer in the absence of structural transformation is obtained by setting the coverage to zero value. The estimated true critical thickness is approximately 4.3 ML for the Ni-capping method and 4.6 ML for the Co-inserting experiment, which are very close to the reported result for the Co-capping experiment.

      • KCI등재

        Flux‑coupling fault current limiter design for VSC DC grids

        Jun Xu,Lei Gao,Guangyang Zhou,Huiyuan Zhang 전력전자학회 2022 JOURNAL OF POWER ELECTRONICS Vol.22 No.1

        DC circuit breakers (DCCBs) are used to clear short-circuit faults in several milliseconds. However, short-circuit fault current can reach extreme values. Fault current limiters (FCLs) can present high inductance values during the short-circuit fault period. Thus, they have received considerable attention for reducing the high current breaking requirements of DCCBs. Three types of magnetic flux-coupling solid-state FCLs are designed in this paper, which include mutual inductors and several power electronic switches. In addition, the FCL impedance can be controlled by power electronic switches. By comparing the current limit capacities and structural complexities among the three types of FCLs, a more applicable limiter referred to as a flux-coupling DC current limiter (FCDCCL) can be installed on VSC DC grids. Finally, a simulation model is built in PSCAD/EMTDC based on a ± 10 kV/400 A DC system. The simulation results verify that a significant change in the limiting current can be achieved by the proposed FCDCCL, which can be extended to actual VSC DC grids.

      • SCIESCOPUSKCI등재

        Investigation on Oil-paper Degradation Subjected to Partial Discharge Using Chaos Theory

        Gao, Jun,Wang, Youyuan,Liao, Ruijin,Wang, Ke,Yuan, Lei,Zhang, Yiyi The Korean Institute of Electrical Engineers 2014 Journal of Electrical Engineering & Technology Vol.9 No.5

        In this paper, oil-paper samples composed of transformer windings were used to investigate the insulation degradation process subjected to partial discharge (PD), with artificial defects inside to simulate the PD induced insulation degradation. To determine appropriate test voltages, the breakdown time obtained through a group of accelerated electrical degradation tests under high voltages was firstly fitted by two-parameter Weibull model to acquire the average breakdown time, which was then applied to establish the inverse power law life model to choose advisable test voltages. During the electrical degradation process, PD signals were synchronously detected by an ultra-high frequency (UHF) sensor from inception to breakdown. For PD analysis, the whole degradation process was divided into ten stages, and chaos theory was introduced to analyze the variation of three chaotic parameters with the development of electrical degradation, namely the largest Lyapunov exponent, correlation dimension and Komogorov entropy of PD amplitude time series. It is shown that deterministic chaos of PD is confirmed during the oil-paper degradation process, and the obtained results provide a new effective tool for the diagnosis of degradation of oil-paper insulation subjected to PD.

      • KCI등재

        Investigation on Oil-paper Degradation Subjected to Partial Discharge Using Chaos Theory

        Jun Gao,Youyuan Wang,Ruijin Liao,Ke Wang,Lei Yuan,Yiyi Zhang 대한전기학회 2014 Journal of Electrical Engineering & Technology Vol.9 No.5

        In this paper, oil-paper samples composed of transformer windings were used to investigate the insulation degradation process subjected to partial discharge (PD), with artificial defects inside to simulate the PD induced insulation degradation. To determine appropriate test voltages, the breakdown time obtained through a group of accelerated electrical degradation tests under high voltages was firstly fitted by two-parameter Weibull model to acquire the average breakdown time, which was then applied to establish the inverse power law life model to choose advisable test voltages. During the electrical degradation process, PD signals were synchronously detected by an ultra-high frequency (UHF) sensor from inception to breakdown. For PD analysis, the whole degradation process was divided into ten stages, and chaos theory was introduced to analyze the variation of three chaotic parameters with the development of electrical degradation, namely the largest Lyapunov exponent, correlation dimension and Komogorov entropy of PD amplitude time series. It is shown that deterministic chaos of PD is confirmed during the oil-paper degradation process, and the obtained results provide a new effective tool for the diagnosis of degradation of oil-paper insulation subjected to PD.

      • Mobile sand barriers for windblown sand mitigation: Effects of plane layout and included angle

        Li Gao,Jian-jun Cheng,Bo-song Ding,Jia Lei,Yuan-feng An,Ben-teng Ma 한국풍공학회 2022 Wind and Structures, An International Journal (WAS Vol.34 No.3

        Mobile sand barriers are a new type sand-retaining structure that can be moved and arranged according to the engineering demands of sand control. When only used for sand trapping, mobile sand barriers could be arranged in single row. For the dual purposes of sand trapping and sand stabilization, four rows of mobile sand barriers can be arranged in a staggered form. To reveal the effect of plane layout, the included angle between sand barrier direction and wind direction on the characteristics of flow fields and the sand control laws of mobile sand barriers, numerical computations and wind tunnel tests were conducted. The results showed that inflows deflected after passing through staggered arrangement sand barriers due to changes in included angle, and the sand barrier combination exerted successive wind resistance and group blocking effects. An analysis of wind resistance efficiency revealed that the effective protection length of staggered arrangement sand barriers approximately ranged from the sand barrier to 10H on the leeward side (H is sand barrier height), and that the effective protection length of single row sand barriers roughly ranged from 1H on the windward side to 20H on the leeward side. The distribution of sand deposit indicated that the sand interception increased with increasing included angle in staggered arrangement. The wind-breaking and sand-trapping effects were optimal when included angle between sand barrier direction and wind direction is 60°-90°.

      • KCI등재

        Insufficient radiofrequency ablation-induced autophagy contributes to the rapid progression of residual hepatocellular carcinoma through the HIF-1α/BNIP3 signaling pathway

        ( Wen-lei Xu ),( Shao-hong Wang ),( Wen-bing Sun ),( Jun Gao ),( Xue-mei Ding ),( Jian Kong ),( Li Xu ),( Shan Ke ) 생화학분자생물학회(구 한국생화학분자생물학회) 2019 BMB Reports Vol.52 No.4

        Currently speaking, it is noted that radiofrequency ablation (RFA) has been the most widely used treatment for hepatocellular carcinoma (HCC) occurring in patients. However, accumulating evidence has demonstrated that the incidence of insufficient RFA (IRFA) may result in the identified rapid progression of residual HCC in the patient, which can greatly hinder the effectiveness and patient reported benefits of utilizing this technique. Although many efforts have been proposed, the underlying mechanisms triggering the rapid progression of residual HCC after IRFA have not yet been fully clarified through current research literature reviews. It was shown in this study that cell proliferation, migration and invasion of residual HepG2 and SMMC7721 cells were significantly increased after the IRFA was simulated in vitro. In other words, it is noted that IRFA could do this by enhancing the image of autophagy of the residual HCC cell via the HIF-1 α/BNIP3 pathway. Consequently, the down-regulation of BNIP3 may result in the inhibition of the residual HCC cell progression and autophagy after IRFA. Our present study results suggest that IRFA could promote residual HCC cell progression in vitro by enhancing autophagy via the HIF-1 α/BNIP3 pathway. For this reason, it is noted that the targeting of the BNIP3 may be useful in preventing the rapid growth and metastasis of residual HCC after IRFA. [BMB Reports 2019; 52(4): 277-282]

      • Smad4 Expression in Hepatocellular Carcinoma Differs by Hepatitis Status

        Yao, Lei,Li, Fu-Jun,Tang, Zhi-Qiang,Gao, Shuang,Wu, Qe-Quan Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.4

        Aims: Primary hepatocellular carcinoma (HCC) is a common malignancy often related to hepatitis viral infection. Smad4 is known to mediate the TGF-${\beta}$ pathway to suppress tumorigenesis. However, the function of Smad4 in HCC is still controversial. In this study we compared levels of Smad4 in HCC tissues with or without hepatitis virus infection and adjacent normal-appearing liver. Methods: Samples from HCC patients were analyzed for Smad4 protein and mRNA expression by immunohistochemistry (IHC), RT-PCR and Western blotting. Results: We found that tumor tissues expressed less Smad4 mRNA and protein than the adjacent tissues. Most HCC tumor tissues were negative for Smad4 in IHC staining, while the majority of adjacent tissues were positively stained. Interestingly, protein levels were higher in HCC tissues with viral hepatitis than those without virus infection. Suppression of expression appeared closely related to HCC, so that Smad4 appears to function as a tumor suppressor gene (TSG). Conclusion: Patients with hepatitis viral infection, at higher risk for HCC, exhibited increased Smad4 protein expression suggesting hepatitis virus may modulate Smad4 expression, which is functionally distinct from its putative role as a TSG. Smad4 expression may thus be an applicable marker for diagnosis and/or a target to develop therapeutic agents for HCC.

      • KCI등재

        Outcomes of Microendoscopic Discectomy and Percutaneous Transforaminal Endoscopic Discectomy for the Treatment of Lumbar Disc Herniation: A Comparative Retrospective Study

        Arjun Sinkemani,Xin Hong,Zeng-Xin Gao,Su-Yang Zhuang,Zan-Li Jiang,Shao-Dong Zhang,Jun-Ping Bao,Lei Zhu,Pei Zhang,Xin-Hui Xie,Feng Wang,Xiao-Tao Wu 대한척추외과학회 2015 Asian Spine Journal Vol.9 No.6

        Study Design: Retrospective, case control evaluation of 86 patients who underwent microendoscopic discectomy (MED) and percutaneous transforaminal endoscopic discectomy (PTED) for the treatment of lumbar disc herniation (LDH). Purpose: To evaluate the safety and the outcomes of MED and PTED for the treatment of LDH. Overview of Literature: MED and PTED are minimally invasive surgical techniques for lower back pain. Studies to date have shown that MED and PTED are safe and effective treatment modalities for LDH. Methods: A retrospective study was performed in patients with LDH treated with MED (n=50) and transforaminal endoscopic discectomy (PTED; n=36) in our hospital. All patients were followed-up with self-evaluation questionnaires, Oswestry disability index (ODI), medical outcomes study 36-item short form health survey and MacNab criteria. All the patients in both groups were followed up to 12 months after the operation. Results: ODI questionnaire responses were not statistically different between the MED and PTED groups (53.00 vs. 48.72) before treatment. Average scores and minimal disability after 5 days to 12 months of follow-up were 4.96 in the MED group and 3.61 in the PTED group. According to MacNab criteria, 92.0% of the MED group and 94.4% of the PTED group had excellent or good results with no significant difference. Conclusions: There was no significant difference between MED and PTED outcomes. Further large-scale, randomized studies with long-term follow-up are needed.

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