Investigation of an STATCOM-based Energy Stored Quasi-Z Source Cascaded H-bridgeInverter Photovoltaic Power System

Weihua Liang,Yitao Liu,Shiqi Jiang,Jianchun Peng,Hui Jiang 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

The energy stored quasi-Z source cascaded Hbridge (ES-qZS-CHB) inverter is widely used in photovoltaic (PV) power generation system because of its unique advantages. However, the existing researches on ESqZS-CHB inverter PV power system mainly focus on the transmission of active power, but pay little attention to reactive power, causing the ES-qZS-CHB inverter PV power system cannot compensate reactive power or improve system performance. This paper proposes a PV power generation and static synchronous compensator based ESqZS-CHB inverter system, to implement the PV generation and reactive power compensation at the same time. Simulation and experimental results verify the system’s excellent performance.

Interactive Effects of Ultraviolet Radiation and Dissolved Organic Carbon on Phytoplankton Growth and Photosynthesis in Sanya Bay, Northern South China Sea

Jianzu Liao,Weihua Zhou,Jie Xu,Xiangcheng Yuan,Yuxian Liang,Yajuan Guo,Hui Huang,Sheng Liu,Aimin Long 한국해양과학기술원 2019 Ocean science journal Vol.54 No.4

The effects of a simulated climate change scenario, i.e., increased ultraviolet radiation (UVR) and dissolved organic carbon (DOC), on the growth and photosynthesis of tropical coastal phytoplankton were evaluated in Sanya Bay, northern South China Sea, in summer. Microcosm experiments were conducted at two contrasting stations (Stns S1 and S2) with three different UVR treatments and two DOC addition treatments. Our results showed that natural sunlight UVR or increased UV-B did not affect phytoplankton biomass and primary production. However, increased UV-B significantly decreased the proportion of picophytoplankton and the efficiency of carbon fixation at Stn S2. DOC enhancement caused negative effects on primary production under natural sunlight UVR only at Stn S1. Interactive effects of UVR and DOC addition on phytoplankton biomass and primary production were detected at Stn S1, due to the negative effects of DOC being eliminated under the increased UV-B condition. The lack of interactive effects at Stn S2 were likely due to the differences with Stn S1 in terms of light acclimation and biological interaction. In summary, this future climate change scenario will probably not affect the photosynthetic CO2 fixation and biomass of natural phytoplankton in Sanya Bay.

A simple data assimilation method to improve atmospheric dispersion based on Lagrangian puff model

Li, Ke,Chen, Weihua,Liang, Manchun,Zhou, Jianqiu,Wang, Yunfu,He, Shuijun,Yang, Jie,Yang, Dandan,Shen, Hongmin,Wang, Xiangwei Korean Nuclear Society 2021 Nuclear Engineering and Technology Vol.53 No.7

To model the atmospheric dispersion of radionuclides released from nuclear accident is very important for nuclear emergency. But the uncertainty of model parameters, such as source term and meteorological data, may significantly affect the prediction accuracy. Data assimilation (DA) is usually used to improve the model prediction with the measurements. The paper proposed a parameter bias transformation method combined with Lagrangian puff model to perform DA. The method uses the transformation of coordinates to approximate the effect of parameters bias. The uncertainty of four model parameters is considered in the paper: release rate, wind speed, wind direction and plume height. And particle swarm optimization is used for searching the optimal parameters. Twin experiment and Kincaid experiment are used to evaluate the performance of the proposed method. The results show that the proposed method can effectively increase the reliability of model prediction and estimate the parameters. It has the advantage of clear concept and simple calculation. It will be useful for improving the result of atmospheric dispersion model at the early stage of nuclear emergency.

A reduced time-varying model for a long beam on elastic foundation under moving loads

Guiming Mei,Caijin Yang,Shulin Liang,Jiangwen Wang,Dong Zou,Weihua Zhang,Yunshi Zhao,Zhong Huang,Shuqi Song,Mengying Tan,Yao Cheng,Bingrong Miao 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.9

Dynamics of a long beam on the elastic foundation subjected to moving loads is studied in the present paper. The sliding window technique is used to dynamically truncate the long beam and a reduced time-varying beam system is obtained. The Hamilton’s principle is employed to establish the equations of motion of the reduced system. The variable separation method is adopted to solve dynamical responses of the reduced system. Examples of a long simply supported Timoshenko beam on the nonlinear foundation subjected to a single moving load and multiple loads are included. Numerical results of the reduced model compared with the ones obtained from the moving element model adapted in literature are carried out to show the validity and the good efficiency of the method proposed in the present paper.

The impacts of resveratrol on the retinal degeneration in a rat model of retinitis pigmentosa induced by alkylation: an in-vivo study

Weiming Yan,Yan Sun,Yutong Wang,Wangjiao Liang,Yuxin Xia,Weihua Yan,Meizhu Chen,Tao Chen,Dongliang Li 한국통합생물학회 2023 Animal cells and systems Vol.27 No.1

Upregulation of Sirtuin Type 1 (SIRT1), a nicotinamide adeninedinucleotide (NAD+)-dependentdeacetylase, has been proved to protect against ample ocular diseases, while its effect onretinitis pigmentosa (RP) has not been illustrated. The study was aimed to explore the impactsof resveratrol (RSV), a SIRT1 activator, on the photoreceptor degeneration in a rat model of RPinduced by N-methyl-N-nitrosourea (MNU), an alkylation. The rats were induced RP phenotypesvia the intraperitoneal injection of MNU. The electroretinogram was conducted and revealedthat RSV could not prevent the decline of retinal function in the RP rats. The optical coherencetomography (OCT) and the retinal histological examination were performed and showed thatthe reduced thickness of the outer nuclear layer (ONL) was not preserved by RSV intervention. The immunostaining technique was applied. Afther the MNU administration, the number of theapoptotic photoreceptors in the ONL throughout the retinasand the number of microglia cellspresent among the outer part throughout the retinas were not significantly reduced by RSV. Western blotting was also performed. The data showed that the level of SIRT1 protein wasdecreased after MNU administration, while RSV was not able to obviously alleviate thedownregulation. Our data together indicated that RSV was not able to rescue thephotoreceptor degeneration in the MNU-induced RP rats, which might be due to the MNUinducedconsumption of the NAD+.

In Vitro Effects of SB202190 on Echinococcus granulosus

Hailong Lv,Siyuan Li,Jing Zhang,Weihua Liang,Xiaoling Mu,Yufeng Jiang 대한기생충학열대의학회 2013 The Korean Journal of Parasitology Vol.51 No.2

Spillage of cyst contents during surgical operation is the major cause of recurrence after hydatid cyst surgery. Instillation of a scolicidal agent into a hepatic hydatid cyst is the most commonly employed measure to prevent this complication. SB202190 is a pyridinyl imidazole derivative and is known to be a specific inhibitor of p38 MAPK. In the present study, the scolicidal effect of SB202190 was investigated. Freshly isolated Echinococcus granulosus protoscolices were subjected to SB202190 treatment (10, 20, 40, and 80 μM), and the effects on parasite viability were monitored by trypan blue staining. Corresponding effects were visualized by scanning and transmission electron microscopy. Dose-dependent protoscolex death within a few days of SB202190 treatment was observed. Although the in vitro scolicidal effect of SB202190 was satisfactory, the in vivo efficacy of this drug and also possible side effects remain to be further investigated.

Low-Temperature Scanning Near-Field Optical Microscope and Spectroscopy: Application in Quantum Well Device

Gengzhao XU,Xing ZHU,Hu Liang,Kay May Lau,Weihua ZHANG,Yun-Dong Qi 한국물리학회 2005 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.47 No.1

We have constructed a versatile low-temperature scanning near-field optical microscope (LTSNOM) with the capability of near-field imaging and spectroscopy, operating at liquid nitrogen (LN) temperature. A sample is illuminated either electronically or optically by introducing a laser beam through specially designed coaxial double lenses and an optical fiber. The detected optical signal is transmitted via a fiber tip to a photoelectric multiplier tube (PMT) or a spectrometer. Shear-force detection by using a tuning-fork technique is applied to maintain the tip-sample distance. A shearforce topographic image, an optical image and a local spectrum can be obtained simultaneously. The whole scanning head is enclosed inside a container which is immersed in liquid nitrogen in a storage Dewar during the measurement. We have used this LT-SNOM to study the electroluminescence (EL) properties of InGaN/GaN multiple-quantum-well light-emitting diodes (LEDs), at both room temperature and liquid nitrogen temperature. Low-temperature experiments with the LT-SNOM show the stability of our construction and stable image acquisition at LN temperature. The results show that at room temperature the EL intensity distribution is quite inhomogeneous with islands like bright spots, and at LN temperature the EL intensity increased dramatically and the inhomogeneity reduced greatly. Furthermore, the near-field spectra show a peak at a higher photon energy at around 2.95 eV at low temperature, in addition to the 2.7 eV peak observed by far field at room temperature. The results indicate that the self-organized In rich regions play a key role in the EL properties of these LEDs, which act as radiation recombination centers. In conjunction with nearfield spectroscopy, the possible mechanism of this phenomenon is explained in terms of irradiative recombination in the MQWs, as well as the quantum-confined Starks effect.

Effect of Overfeeding on Plasma Parameters and mRNA Expression of Genes Associated with Hepatic Lipogenesis in Geese

Han, Chunchun,Wang, Jiwen,Xu, Hengyong,Li, Liang,Ye, Jianqiang,Li, Jiang,Zhuo, Weihua Asian Australasian Association of Animal Productio 2008 Animal Bioscience Vol.21 No.4

The aim of our study was to research the effect of overfeeding on plasma parameters and mRNA expression of genes associated with hepatic lipogenesis in the Sichuan white goose and Landes goose. Fifty-four male Landes geese and 57 male Sichuan white geese were hatched on the same day under the same feeding conditions. After overfeeding for 14 days, (1) extrahepatic adipose tissues grew greatly in the Sichuan white geese, while more lipid accumulated in liver tissue in the Landes geese. (2) Sichuan white geese had a higher plasma concentration of triacylglycerols (TG), lipoproteins and insulin than the Landes geese. However, the Landes geese exhibited higher increase of plasma concentrations of TG, lipoproteins and insulin, with greater decrease of the diacylglycerol acyltransferase 2 (DGAT2) activity and DGAT2 mRNA level and a smller decrease of plasma glucose concentration. In addition, the mRNA level of MTP and LPL in liver was down- and up- regulated by overfeeding, respectively. (3) The correlations between the activity of LPL and the proportions of subcutaneous adipose tissue, abdominal adipose tissue, and liver weight, and the plasma concentration of VLDL were different in the two breeds. (4) The proportion of fatty liver weight was positively correlated to plasma concentrations of VLDL and TG in the overfed Sichuan white geese. Such a relationship did not exist in the Landes geese. (5) The activity of DGAT2 and its mRNA abundance in liver had significant negative correlations with the TG content in liver lipid and plasma insulin level in the Landes geese, while in the Sichuan white geese they had negative correlation (p>0.05) with TG concentration in liver lipid and had significant positive correlation with VLDL and TG concentrations in plasma.

Study on Thermal Load Capacity of Transmission Line Based on IEEE Standard

Song, Fan,Wang, Yanling,Zhao, Lei,Qin, Kun,Liang, Likai,Yin, Zhijun,Tao, Weihua Korea Information Processing Society 2019 Journal of information processing systems Vol.15 No.3

With the sustained and rapid development of new energy sources, the demand for electric energy is increasing day by day. However, China's energy distribution is not balanced, and the construction of transmission lines is in a serious lag behind the improvement of generating capacity. So there is an urgent need to increase the utilization of transmission capacity. The transmission capacity is mainly limited by the maximum allowable operating temperature of conductor. At present, the evaluation of transmission capacity mostly adopts the static thermal rating (STR) method under severe environment. Dynamic thermal rating (DTR) technique can improve the utilization of transmission capacity to a certain extent. In this paper, the meteorological parameters affecting the conductor temperature are analyzed with the IEEE standard thermal equivalent equation of overhead transmission lines, and the real load capacity of 220 kV transmission line is calculated with 7-year actual meteorological data in Weihai. Finally, the thermal load capacity of DTR relative to STR under given confidence is analyzed. By identifying the key parameters that affect the thermal rating and analyzing the relevant environmental parameters that affect the conductor temperature, this paper provides a theoretical basis for the wind power grid integration and grid intelligence. The results show that the thermal load potential of transmission lines can be effectively excavated by DTR, which provides a theoretical basis for improving the absorptive capacity of power grid.

Study on Thermal Load Capacity of Transmission Line Based on IEEE Standard

Fan Song,Yanling Wang,Lei Zhao,Kun Qin,Likai Liang,Zhijun Yin,Weihua Tao 한국정보처리학회 2019 Journal of information processing systems Vol.15 No.3

With the sustained and rapid development of new energy sources, the demand for electric energy is increasingday by day. However, China’s energy distribution is not balanced, and the construction of transmission lines isin a serious lag behind the improvement of generating capacity. So there is an urgent need to increase theutilization of transmission capacity. The transmission capacity is mainly limited by the maximum allowableoperating temperature of conductor. At present, the evaluation of transmission capacity mostly adopts the staticthermal rating (STR) method under severe environment. Dynamic thermal rating (DTR) technique canimprove the utilization of transmission capacity to a certain extent. In this paper, the meteorological parametersaffecting the conductor temperature are analyzed with the IEEE standard thermal equivalent equation ofoverhead transmission lines, and the real load capacity of 220 kV transmission line is calculated with 7-yearactual meteorological data in Weihai. Finally, the thermal load capacity of DTR relative to STR under givenconfidence is analyzed. By identifying the key parameters that affect the thermal rating and analyzing therelevant environmental parameters that affect the conductor temperature, this paper provides a theoretical basisfor the wind power grid integration and grid intelligence. The results show that the thermal load potential oftransmission lines can be effectively excavated by DTR, which provides a theoretical basis for improving theabsorptive capacity of power grid.