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- 저자 : Yan Du (검색결과 167 건)
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Du, Wei,Ma, Xue-Lei,Zhao, Chong,Liu, Tao,Du, Yu-Liang,Kong, Wei-Qi,Wei, Ben-Ling,Yu, Jia-Yun,Li, Yan-Yan,Huang, Jing-Wen,Li, Zi-Kang,Liu, Lei Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.2
Background: MicroRNAs (miRNAs) are an abundant class of endogenous small non-coding RNAs of 20-25 nucleotides in length that function as negative gene regulators. MiRNAs play roles in most biological processes, as well as diverse human diseases including cancer. Recently, many studies investigated the association between SNPs in miR-146a rs2910164, miR-196a2 rs11614913, miR-149 rs229283, miR-499 rs3746444 and colorectal cancer (CRC), which results have been inconclusive. Methodology/Principal Findings: PubMed, EMBASE, CNKI databases were searched with the last search updated on November 5, 2013. For miR-196a2 rs11614913, a significantly decreased risk of CRC development was observed under three genetic models (dominant model: OR = 0.848, 95%CI: 0.735-0.979, P = 0.025; recessive model: OR = 0.838, 95%CI: 0.721-0.974, P = 0.021; homozygous model: OR = 0.754, 95%CI: 0.627-0.907, P = 0.003). In the subgroup analyses, miR-$196a2^*T$ variant was associated with a significantly decreased susceptibility of CRC (allele model: OR = 0.839, 95%CI: 0.749-0.940, P = 0.000; dominant model: OR = 0.770, 95%CI: 0.653-0.980, P = 0.002; recessive model: OR = 0.802, 95%CI: 0.685-0.939, P = 0.006; homozygous model: OR = 0.695, 95%CI: 0.570-0.847, P = 0.000). As for miR-149 rs2292832, the two genetic models (recessive model: OR = 1.199, 95% CI 1.028-1.398, P = 0.021; heterozygous model: OR = 1.226, 95% CI 1.039-1.447, P = 0.013) demonstrated increased susceptibility to CRC. On subgroup analysis, significantly increased susceptibility of CRC was found in the genetic models (recessive model: OR = 1.180, 95% CI 1.008-1.382, P = 0.040; heterozygous model: OR = 1.202, 95% CI 1.013-1.425, P = 0.013) in the Asian group. Conclusions: These findings supported that the miR-196a2 rs11614913 and miR-149 rs2292832 polymorphisms may contribute to susceptibility to CRC.
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Adaptive Virtual Impedance of Grid-Tied Inverters to Enhance the Stability in a Weak Grid
Yan Du,Qingqing Sun,Xiangzhen Yang,Linbo Cui,Jian Zhang,Fei Wang 대한전기학회 2019 Journal of Electrical Engineering & Technology Vol.14 No.3
In a weak grid, especially with a grid-voltage proportional feedforward controller, the grid-tied inverter tends to interact with the grid impedance and thus suff ers from poor power quality and even instability. In order to improve the stability, serial-parallel virtual impedance based on the derivative controllers of grid current and voltage is proposed in this paper. With the aim of optimizing the performance of the inverter for a variety of grid impedance, these derivative coeffi cients are adaptively tuned by the constraint of a minimum leading phase which is determined by the phase margin and the current tracking response. With this proposed adaptive virtual impedance, the grid-tied inverter can operate stably under a wide variety of grid impedance and voltage harmonic rejection performance is also improved. Simulation and experimental results validate the eff ectiveness of the proposed method and design methodology.
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Du, Zi-Yan,Shi, Min-Hua,Ji, Cheng-Hong,Yu, Yong Asian Pacific Journal of Cancer Prevention 2015 Asian Pacific journal of cancer prevention Vol.16 No.4
Aims: Pleiotrophin (PTN), an angiogenic factor, is associated with various types of cancer, including lung cancer. Our aim was to investigate the possibility of using serum PTN as an early indicator regarding disease diagnosis, classification and prognosis, for patients with non-small cell lung cancer (NSCLC). Methods: Significant differences among PTN levels in patients with small cell lung cancer (SCLC, n=40), NSCLC (n=136), and control subjects with benign pulmonary lesions (n=21), as well as patients with different pathological subtypes of NSCLC were observed. Results: A serum level of PTN of 300.1 ng/ml, was determined as the cutoff value differentiating lung cancer patients and controls, with a sensitivity and specificity of 78.4% and 66.7%, respectively. Negative correlations between serum PTN level and pathological differentiation level, stage, and survival time were observed in our cohort of patients with NSCLC. In addition, specific elevation of PTN levels in pulmonary tissue in and around NSCLC lesions in comparison to normal pulmonary tissue obtained from the same subjects was also observed (n=2). Conclusion: This study suggests that the serum PTN level of patients with NSCLC could be an early indicator for diagnosis and prognosis. This conclusion should be further assessed in randomized clinical trials.
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Yan-bin Du,Guoao Wu,Ying Tang,Huajun Cao,Shihao Liu 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.8 No.6
Reliability is the key performance indicator for remanufactured machine tools to be approved by customers. Reliability allocation is an important task that needs to be done in the design phase of remanufactured machine tools to ensure that remanufactured products meet the reliability target requirements. A reliability allocation method for remanufactured machine tools is proposed based on fuzzy evaluation importance and failure influence of each component. The importance of each component is evaluated by five indicators such as complexity of structure, maturity of technology, criticality of fault, difficulty of maintenance, and severity of service condition, in which their weights are determined by the method of analytic hierarchy process (AHP). Failure influence is determined by the proportion of downtime caused by each component in total downtime of machine tools. Finally, the proposed method is illustrated in a numerical case study of NC lathe remanufacturing.
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A virtual synchronous generator adopting dynamic damping without frequency detection
Yan Du,Hanguang Zhao,Xianchuang Zhang,Xiangzhen Yang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5
The grid-connected inverter implementing the virtual synchronous generator (VSG) controller can take advantage of the virtual inertia and damping winding to improve the stability of the frequency and voltage of the power grid. However, PLL in virtual damping winding weakens the damping effect during the transient and increases the complexity of the system. In this paper, a leading-network based damping controller without PLL is proposed after analyzing the inverse effect of PLL on the performance of the damping winding using VSG small-signal models. A phase margin-constrained straightforward parameter setting method for proposed VSG is presented. The correctness of the design is verified on a 5kW hardwarein-loop inverter platform.
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Online broadband grid impedance estimation method based on multi‑objective optimized random PWM
Yan Du,Shiyou Yang,Chunran Gao,Xiangzhen Yang,Houbo Wu,Jianhui Su 전력전자학회 2023 JOURNAL OF POWER ELECTRONICS Vol.23 No.12
Grid-connected inverter (GCI)-based online grid impedance estimation (GIE) can be used in the fields of grid state monitoring, fault diagnosis, and the stability control of grid-connected equipment, which can collectively improve the intelligence of GCI. However, the available frequency range of GCI-based GIE is limited by the bandwidth of the controller because a perturbation signal is injected into the reference current. To broaden the bandwidth of grid impedance estimation, an online GIE technology based on multi-objective optimized random pulse width modulation (MOO-RPWM) is proposed in this paper. Besides taking advantage of the harmonic dispersion characteristic of RPWM, the distribution of the switching frequency is further optimized by the constraints on the measurement accuracy and the total harmonic distortion (THD) of the grid current. Moreover, the frequency boundary is constrained by the frequency range of GIE, the stability of the system, and power loss. A genetic algorithm (GA) is applied to obtain the switching frequency sequence that satisfies the optimization targets. A single-phase grid-connected inverter system is built on a StarSim hardware-in-the-loop (HIL) platform to verify that MOO-RPWM-based GIE has the advantages of a broad GIE range, high accuracy, and low disturbance.
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Failure Mode, Effects and Criticality Analysis of Remanufactured Machine Tools in Service
Yan-bin Du,Lan Liao,Le-su Wang 한국정밀공학회 2017 International Journal of Precision Engineering and Vol.18 No.3
Failure Mode, Effects and Criticality Analysis (FMECA) of remanufactured machine tools is one of the key issues for improving their quality and reliability. According to the characteristics of remanufactured machine tools and the basic principle of FMECA, the method of failure mode analysis for remanufactured machine tools in service is proposed, with the FMECA procedure being expounded in detail. In addition, failure criticality of each failure mode for remanufactured machine tools is analyzed by risk priority number (RPN) method. Finally, the method is demonstrated in a case study of remanufactured YX3120 gear hobbing machine. The results from the case study are discussed and conclusions are drawn.
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Autonomous Controller Based on Synchronous Generator dq0 Model for Micro Grid Inverters
Yan Du,Jianhui Su,Meiqin Mao,Xiangzhen Yang 전력전자학회 2011 ICPE(ISPE)논문집 Vol.2011 No.5
the parallel operation of voltage source inverter (VSI) in microgrid could benefit from characteristics of synchronous generator (SG) such as the kinetic energy stored in rotor, the self-isochronous and the droop characteristics if inverter can behave like generator in power system. Therefore an autonomous controller based on dq0 model of SG for microgrid inverter is proposed to mimic the above those characteristic of SG. Moreover, the inverter is designed to serve as either UF node or PQ node in micro grid by integrating a virtual primary frequency regulator (VPFR) and a virtual excitation regulator (VER) in the proposed controller. The results of simulation show the excellent performances of the proposed autonomous controller on voltage regulation, power sharing and seamless mode transfer.
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Yan Du,Rizhi Chen 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.9
An efficient and reusable catalyst was developed by depositing palladium nanoparticles on an amine-functionalized ceramic membrane support using a nanoparticulate colloidal impregnation method. The as-prepared Pdloaded ceramic membrane support was characterized by XRD, SEM, EDS, TEM, XPS, ICP, and its catalytic properties were investigated in the liquid-phase p-nitrophenol hydrogenation. A comparative study was also made with the palladium nanoparticles deposited on an amine-functionalized ceramic membrane support by an impregnation-reduction method. The palladium nanoparticles could be homogeneously immobilized on the ceramic membrane support surface, and exhibited excellent catalytic performance in the p-nitrophenol hydrogenation. The catalytic activity of the Pdloaded ceramic membrane support prepared by the nanoparticulate colloidal impregnation method increased by 16.6% compared to that of impregnation-reduction method. In the nanoparticulate colloidal impregnation method, palladium nanoparticles were presynthesized, higher loading of Pd(0) could be obtained, resulting in better catalytic activity. The as-prepared Pd-loaded ceramic membrane support could be easily reused for several cycles without appreciable degradation of catalytic activity.
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