닫혀진 보제 끈 이론의 새로운 양자화

한승기, Wu Ke, Zhang Yuan-Zhong 忠北大學校部設基礎科學硏究所 1987 自然科學硏究 Vol.1 No.1

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Zero-Current Phenomena Analysis of the Single IGBT Open Circuit Faults in Two-Level and Three-Level SVGs

Ke Wang,Hong-Lu Zhao,Yi Tang,Xiao Zhang,Chuan-Jin Zhang 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.2

The fact that the reliability of IGBTs has become a more and more significant aspect of power converters has resulted in an increase in the research on the open circuit (OC) fault location of IGBTs. When an OC fault occurs, a zero-current phenomena exists and frequently appears, which can be found in a lot of the existing literature. In fact, fault variables have a very high correlation with the zero-current interval. In some cases, zero-current interval actually decides the most significant fault feature. However, very few of the previous studies really explain or prove the zero-current phenomena of the fault current. In this paper, the zero-current phenomena is explained and verified through mathematical derivation, based on two-level and three-level NPC static var generators (SVGs). Mathematical models of single OC fault are deduced and it is concluded that a zero-current interval with a certain length follows the OC faults for both two-level and NPC three-level SVGs. Both inductive and capacitive reactive power situations are considered. The unbalanced load situation is discussed. In addition, simulation and experimental results are presented to verify the correctness of the theoretical analysis.

MiRNA Synergistic Network Construction and Enrichment Analysis for Common Target Genes in Small-cell Lung Cancer

Zhang, Tie-Feng,Cheng, Ke-Wen,Shi, Wei-Yin,Zhang, Jin-Tao,Liu, Ke-Di,Xu, Shu-Guang,Chen, Ji-Quan Asian Pacific Journal of Cancer Prevention 2012 Asian Pacific journal of cancer prevention Vol.13 No.12

Background: Small-cell lung cancer (also known as SCLC) is an aggressive form and untreated patients generally die within about 3 months. To obtain further insight into mechanism underlying malignancy with this cancer, an miRNA synergistic regulatory network was constructed and analyzed in the present study. Method: A miRNA microarray dataset was downloaded from the NCBI GEO database (GSE27435). A total of 546 miRNAs were identified to be expressed in SCLC cells. Then a miRNA synergistic network was constructed, and the included miRNAs mapped to the network. Topology analysis was also performed to analyze the properties of the synergistic network. Consequently, we could identified constitutive modules. Further, common target genes of each module were identified with CFinder. Finally, enrichment analysis was performed for target genes. Results: In this study, a miRNA synergistic network with 464 miRNAs and 2981 edges was constructed. According to the topology analysis, the topological properties between the networks constructed by LC related miRNAs and LC unrelated miRNAs were significantly different. Moreover, a module cilque0 could be identified in our network using CFinder. The module included three miRNAs (hsa-let-7c, hsa-let-7b and hsa-let-7d). In addition, several genes were found which were predicted to be common targets of cilque0. The enrichment analysis demonstrated that these target genes were enriched in MAPK signaling pathways. Conclusions: Although limitations exist in the current data, the results uncovered here are important for understanding the key roles of miRNAs in SCLC. However, further validation is required since our results were based on microarray data derived from a small sample size.

A Novel Virtual Space Vector Modulation Strategy for the Neutral-Point Potential Comprehensive Balance of Neutral-Point-Clamped Converters

Zhang, Chuan-Jin,Tang, Yi,Han, Dong,Zhang, Hui,Zhang, Xiao,Wang, Ke The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

A novel Virtual Space Vector (VSV) modulation strategy for complete control of potential neutral point (NP) issues is proposed in this paper. The neutral point potential balancing problems of multi-level converters, which include elimination of low frequency oscillations and self-balancing for NP dc unbalance, are investigated first. Then a set of improved virtual space vectors with dynamic adjustment factors are introduced and a multi-objective optimization algorithm which aims to optimize these adjustment factors is presented in this paper. The improved virtual space vectors and the multi-objective optimization algorithm constitute the novel Virtual Space Vector modulation. The proposed novel Virtual Space Vector modulation can simultaneously recover NP dc unbalance and eliminate low frequency oscillations of the neutral point. Experiment results show that the proposed strategy has excellent performance, and that both of the neutral point potential issues can be solved.

Risk Perception and Response to the COVID-19 Infectious Disease Crisis

Ke Zhang,Jae Eun Lee 위기관리 이론과 실천 2021 Crisisonomy Vol.17 No.7

이 연구의 목적은 COVID-19 위험인식하에서의 경제위험, 생활방식, 심리상태와 위험예방행동 간의 관계를 파악하는 데 있다. 분석 결과, COVID-19에 관한 위험인식은 경제위험, 생활방식, 심리상태에 유의미한 영향을 미치는 것으로 나타났다. 이러한 연구 결과를 토대로 감염병 위기에 대한 정책적 시사점은 다음과 같다. 첫째, 감염병 예방을 위한 교육을 실시하기 위해 감염병 특성별 맞춤형 교육 자료의 개발 및 보급, 학교와 교육청의 감염병 관리역량을 제고해야 한다. 둘째, 감염병 질환에서 개인 심리 건강을 지키기 위해서는 심리적 개입과 지원 등의 대처방안이 중요하다. 셋째, COVID-19 로 인한 경제위험은 정부차원의 제도 마련이 필요하다. COVID-19 확산의 장기성, 높은 치사율과 피해의 정도 등을 고려하면, 재난지원금이나 재난기본소득만으로는 해결되기 어려우므로 조세제도, 재난지원금, 재난기본소득제도 등을 연계하는 것이 필요하다. The purpose of this study is to identify the relationship between economic risk, lifestyle, psychological state, and risk prevention behavior under COVID-19 risk perception. As a result of the analysis, it was found that risk perception regarding COVID-19 has a significant effect on economic risk, lifestyle, and psychological state. Based on these research results, the policy implications for the infectious disease crisis are as follows. First, in order to conduct education for the prevention of infectious diseases, it is necessary to develop and disseminate educational materials for each characteristic of infectious disease, and to enhance the infectious disease management capabilities of schools and offices of education. Second, in order to protect individual psychological health from infectious diseases, it is important to take measures such as psychological intervention and support. Third, the economic risk caused by COVID-19 requires the establishment of an institution at the government level. Considering the long-term spread of COVID-19, the high fatality rate and the degree of damage, it is difficult to solve the problem with disaster subsidies or disaster basic income alone, so it is necessary to link the tax system, disaster subsidy, and disaster basic income system.

Cytosolic escape of mitochondrial DNA triggers cGAS-STING-NLRP3 axis-dependent nucleus pulposus cell pyroptosis

Zhang Weifeng,Li Gaocai,Luo Rongjin,Lei Jie,Song Yu,Wang Bingjin,Ma Liang,Liao Zhiwei,Ke Wencan,Liu Hui,Hua Wenbin,Zhao Kangcheng,Feng Xiaobo,Wu Xinghuo,Zhang Yukun,Wang Kun,Yang Cao 생화학분자생물학회 2022 Experimental and molecular medicine Vol.54 No.-

Low back pain (LBP) is a major musculoskeletal disorder and the socioeconomic problem with a high prevalence that mainly involves intervertebral disc (IVD) degeneration, characterized by progressive nucleus pulposus (NP) cell death and the development of an inflammatory microenvironment in NP tissue. Excessively accumulated cytosolic DNA acts as a damage-associated molecular pattern (DAMP) that is monitored by the cGAS-STING axis to trigger the immune response in many degenerative diseases. NLRP3 inflammasome-dependent pyroptosis is a type of inflammatory programmed death that promotes a chronic inflammatory response and tissue degeneration. However, the relationship between the cGAS-STING axis and NLRP3 inflammasome-induced pyroptosis in the pathogenesis of IVD degeneration remains unclear. Here, we used magnetic resonance imaging (MRI) and histopathology to demonstrate that cGAS, STING, and NLRP3 are associated with the degree of IVD degeneration. Oxidative stress induced cGAS-STING axis activation and NLRP3 inflammasome-mediated pyroptosis in a STING-dependent manner in human NP cells. Interestingly, the canonical morphological and functional characteristics of mitochondrial permeability transition pore (mPTP) opening with the cytosolic escape of mitochondrial DNA (mtDNA) were observed in human NP cells under oxidative stress. Furthermore, the administration of a specific pharmacological inhibitor of mPTP and self-mtDNA cytosolic leakage effectively reduced NLRP3 inflammasome-mediated pyroptotic NP cell death and microenvironmental inflammation in vitro and degenerative progression in a rat disc needle puncture model. Collectively, these data highlight the critical roles of the cGAS-STING-NLRP3 axis and pyroptosis in the progression of IVD degeneration and provide promising therapeutic approaches for discogenic LBP.

Prognostic Values of VEGF and Endostatin with Malignant Pleural Effusions in Patients with Lung Cancer

Zhang, Yu,Yu, Li-Ke,Lu, Guo-Jun,Xia, Ning,Xie, Hai-Yan,Hu, Wei,Hao, Ke-Ke,Xu, Chun-Hua,Qian, Qian Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.19

Aims: Angiogenesis is important in malignant pleural effusion (MPE) formation and it is regulated by a number of pro- and anti-angiogenic cytokines. The purpose of this study was to evaluate the prognostic value of angiogenic factor vascular endothelial growth factor (VEGF) and angiogenesis inhibitor endostatin in lung cancer patients with MPE, and investigate the relationship between these two kinds of agent. Methods: Using enzyme-linked immunoadsorbent assay, the concentrations of VEGF and endostatin were measured in pleural effusions (PE) and serum from a total of 70 lung cancer patients with MPE and 20 patients with tuberculosis. Results: Compared to patients with tuberculosis, the levels of VEGF and endostatin in both PE and serum were significantly higher in patients with lung cancer. There were statistically significant correlations between VEGF levels in PE and serum (r=0.696, p<0.001), endostatin levels in PE and serum (r=0.310, p=0.022), and VEGF and endostatin levels in PE (r=0.287, p=0.019). Cox multivariate analysis revealed that elevated pleural VEGF and endostatin levels and serum endostatin level were independent predictors of shorter overall survival. Conclusion: Both pro- and anti-angiogenic factors are likely contributors to PE formation. Our results suggest that the levels of VEGF and endostatin in PE, together with endostatin in serum, may be potential prognostic parameters for lung cancer patients with MPE.

Physical properties and chemical composition of the cores in the California molecular cloud

Zhang, Guo-Yin,Xu, Jin-Long,Vasyunin, A. I.,Semenov, D. A.,Wang, Jun-Jie,Dib, Sami,Liu, Tie,Liu, Sheng-Yuan,Zhang, Chuan-Peng,Liu, Xiao-Lan,Wang, Ke,Li, Di,Wu, Zhong-Zu,Yuan, Jing-Hua,Li, Da-Lei,Gao, Springer-Verlag 2018 Astronomy and astrophysics Vol.620 No.-

<P><I>Aims.</I> We aim to reveal the physical properties and chemical composition of the cores in the California molecular cloud (CMC), so as to better understand the initial conditions of star formation.</P><P><I>Methods.</I> We made a high-resolution column density map (18.2′′) with <I>Herschel</I> data, and extracted a complete sample of the cores in the CMC with the fellwalker algorithm. We performed new single-pointing observations of molecular lines near 90 GHz with the IRAM 30m telescope along the main filament of the CMC. In addition, we also performed a numerical modeling of chemical evolution for the cores under the physical conditions.</P><P><I>Results.</I> We extracted 300 cores, of which 33 are protostellar and 267 are starless cores. About 51% (137 of 267) of the starless cores are prestellar cores. Three cores have the potential to evolve into high-mass stars. The prestellar core mass function (CMF) can be well fit by a log-normal form. The high-mass end of the prestellar CMF shows a power-law form with an index <I>α</I> = −0.9 ± 0.1 that is shallower than that of the Galactic field stellar mass function. Combining the mass transformation efficiency (<I>ε</I>) from the prestellar core to the star of 15 ± 1% and the core formation efficiency (CFE) of 5.5%, we suggest an overall star formation efficiency of about 1% in the CMC. In the single-pointing observations with the IRAM 30m telescope, we find that 6 cores show blue-skewed profile, while 4 cores show red-skewed profile. [HCO<SUP>+</SUP>]/[HNC] and [HCO<SUP>+</SUP>]/[N2H<SUP>+</SUP>] in protostellar cores are higher than those in prestellar cores; this can be used as chemical clocks. The best-fit chemical age of the cores with line observations is ~5 × 10<SUP>4</SUP> yr.</P>

Anomalous magnetization jumps in granular Pb superconducting films

Zhang An-Lei,Jiang Wan-Yan,Chen Xing-Hong,Zhang Xiao-Ke,Lu Wen-Lai,Chen Fei,Feng Zhen-Jie,Cao Shi-Xun,Zhang Jin-Cang,Ge Jun-Yi 한국물리학회 2022 Current Applied Physics Vol.35 No.-

In granular superconductors, the grain boundaries are closely related to the vortex dynamics and the macroscopic superconducting properties. In our research, Pb films with different grain sizes were prepared by tuning the substrate temperature. With the grain size decreasing, Pb films are prone to feature the anomalous magnetization jumps in the M − T curves, while in the M − H curves flux avalanche happens. Both phenomena appear in the same region of the H − T phase diagram and thus are considered to have the same origin. The further theoretical analysis shows that with grain size decreasing the pinning mechanism evolves from a mixed δTc and δl pinning to the δl pinning mechanism. The results shed light on the study of pinning mechanism for granular superconductors and is beneficial to the potential application of manipulating vortex pinning by regulation of intrinsic defects.

Transcriptome analysis of the pheromone glands in Noorda blitealis reveals a novel AOX group of the superfamily Pyraloidea

Zhang Zu-Bing,Yin Ning-Na,Long Ji-Ming,Zhang Yong-Ke,Liu Nai-Yong,Zhu Jiaying 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.1

Noorda blitealis (Lepidoptera: Pyraloidea: Crambidae) is a major defoliating pest of Moringa trees. Focusing on its mating and reproduction, here we sequenced and analyzed the transcriptome of its pheromone glands (PGs) with a combination of Illumina sequencing, bioinformatics and phylogenetics approaches, coupled with a genomebased analysis. Transcriptome sequencing led to the yields of approximately 162 million clean reads, which were assembled into 60,578 unigenes and 121,692 transcripts, respectively. From the transcriptome, totally 117 genes encoding eight pheromone biosynthesis enzymes and one pheromone degradation enzyme were identified, 90 of which had complete open reading frames. A comparative analysis between PGs and bodies (removing PGs) revealed a large number of differentially expressed genes, including 79 pheromone biosynthesis and degradation related genes. Of the identified genes, NbliDES12 belonging to the △11 desaturase group was likely to a strong candidate for the desaturation of sex pheromones in N. blitealis, as implied by phylogenetic analyses and expression profiles. Finally and most notably, through genome and transcriptome analyses we discovered, for the first time, a novel aldehyde oxidase 6 (AOX6) group of the superfamily Pyraloidea that have been slightly expanded by gene duplications. Moreover, each orthologous AOX group shared highly conserved gene structure. Together, this current study has characterized the genes associated with sex pheromone biosynthesis and degradation from the PG transcriptome of N. blitealis, and more importantly, identifies a novel AOX group of the Pyraloidea.