A Novel Three-Phase Four-Wire Grid-Connected Synchronverter that Mimics Synchronous Generators

Tan, Qian,Lv, Zhipeng,Xu, Bei,Jiang, Wenqian,Ai, Xin,Zhong, Qingchang The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.6

Voltage and frequency stability issues occur in existing centralized power system due to the high penetration of renewable energy sources, which decrease grid absorptive capacity of them. The grid-connected inverter that mimics synchronous generator characteristics with inertia characteristic is beneficial to electric power system stability. This paper proposed a novel three-phase four-wire grid-connected inverter with an independent neutral line module that mimics synchronous generators. A mathematical model of the synchronous generator and operation principles of the synchronverter are introduced. The main circuit and control parameters design procedures are also provided in detail. A 10 kW prototype is built and tested for further verification. The primary frequency modulation and primary voltage regulation characteristics of the synchronous generator are emulated and automatically adjusted by the proposed circuit, which helps to supports the grid.

A Novel Three-Phase Four-Wire Grid-Connected Synchronverter that Mimics Synchronous Generators

Qian Tan,Zhipeng Lv,Bei Xu,Wenqian Jiang,Xin Ai,Qingchang Zhong 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.6

Voltage and frequency stability issues occur in existing centralized power system due to the high penetration of renewable energy sources, which decrease grid absorptive capacity of them. The grid-connected inverter that mimics synchronous generator characteristics with inertia characteristic is beneficial to electric power system stability. This paper proposed a novel three-phase four-wire grid-connected inverter with an independent neutral line module that mimics synchronous generators. A mathematical model of the synchronous generator and operation principles of the synchronverter are introduced. The main circuit and control parameters design procedures are also provided in detail. A 10 ㎾ prototype is built and tested for further verification. The primary frequency modulation and primary voltage regulation characteristics of the synchronous generator are emulated and automatically adjusted by the proposed circuit, which helps to supports the grid.

Recyclable and biocompatible microgel-based supporting system for positive 3D freeform printing of silicone rubber

Tan Wen See,Shi Qian,Chen Shengyang,Bin Juhari Muhammad Aidil,Song Juha 대한의용생체공학회 2020 Biomedical Engineering Letters (BMEL) Vol.10 No.4

Additive manufacturing (AM) of biomaterials has evolved from a rapid prototyping tool into a viable approach for the manufacturing of patient-specific implants over the past decade. It can tailor to the unique physiological and anatomical criteria of the patient’s organs or bones through precise controlling of the structure during the 3D printing. Silicone elastomers, which is a major group of materials in many biomedical implants, have low viscosities and can be printed with a special AM platform, known as freeform 3D printing systems. The freeform 3D printing systems are composed of a supporting bath and a printing material. Current supporting matrices that are either commercially purchased or synthesized were usually disposed of after retrieval of the printed part. In this work, we proposed a new and improved supporting matrix comprises of synthesized calcium alginate microgels produced via encapsulation which can be recycled, reused, and recovered for multiple prints, hence minimizing wastage and cost of materials. The dehydration tolerance of the calcium alginate microgels was improved through physical means by the addition of glycerol and chemical means by developing new calcium alginate microgels encapsulated with glycerol. The recyclability of the heated calcium alginate microgels was also enhanced by a rehydration step with sodium chloride solution and a recovery step with calcium chloride solution via the ion exchange process. We envisaged that our reusable and recyclable biocompatible calcium alginate microgels can save material costs, time, and can be applied in various freeform 3D printing systems.

Increased Piezo1 channel activity in interstitial Cajal-like cells induces bladder hyperactivity by functionally interacting with NCX1 in rats with cyclophosphamide-induced cystitis

Qian Liu,Bishao Sun,Jiang Zhao,Qingqing Wang,Fan An,Xiaoyan Hu,Zhenxing Yang,Jie Xu,Mingjia Tan,Longkun Li 생화학분자생물학회 2018 Experimental and molecular medicine Vol.50 No.-

The Piezo1 channel is a mechanotransduction mediator, and Piezo1 abnormalities have been linked to several clinical disorders. However, the role of the Piezo1 channel in cystitis-associated bladder dysfunction has not been documented. The current study aimed to discover the functional role of this channel in regulating bladder activity during cyclophosphamide (CYP)-induced cystitis. One hundred four female rats were randomly assigned to the control, CYP-4h, CYP-48h and CYP-8d groups. CYP successfully induced acute or chronic cystitis in these rats. CYP treatment for 48h or 8d significantly increased Piezo1 channel expression in bladder interstitial Cajal-like cells (ICC-LCs), and the increase in CYP-8d rats was more prominent. In addition, 2.5 μM Grammostola spatulata mechanotoxin 4 (GsMTx4) significantly attenuated bladder hyperactivity in CYP-8d rats by inhibiting the Piezo1 channel in bladder ICCLCs. Furthermore, by using GsMTx4 and siRNA targeting the Piezo1 channel, we demonstrated that hypotonic stressinduced Piezo1 channel activation significantly triggered Ca2+ and Na+ influx into bladder ICC-LCs during CYPinduced chronic cystitis. In addition, the Piezo1 channel functionally interacted with the relatively activated reverse mode of Na+/Ca2+ exchanger 1 (NCX1) in bladder ICC-LCs from CYP-8d rats. In conclusion, we suggest that the functional role of the Piezo1 channel in CYP-induced chronic cystitis is based on its synergistic effects with NCX1, which can significantly enhance [Ca2+]i and result in Ca2+ overload in bladder ICC-LCs, indicating that the Piezo1 channel and NCX1 are potential novel therapeutic targets for chronic cystitis-associated bladder hyperactivity.

Protective effect of procyanidin B2 on hydrogen peroxide (H2O2)-induced oxidative damage in MCF-7 cells

Tan Jia-qi,Li Peng-cheng,Li Qian,Tang Jin-tian,Xue Hong-kun 한국응용생명화학회 2020 Applied Biological Chemistry (Appl Biol Chem) Vol.63 No.5

The aim of this study is to assess the cytoprotection and potential molecular mechanisms of procyanidin B2 ( PCB2) on hydrogen peroxide ( H2O2)-induced oxidative damage in MCF-7 cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was performed to determine the viability of MCF-7 cell exposure to H2O2 or PCB2. We measured the antioxidant properties of PCB2 by determining the activities of SOD, GSH-Px, LDH and MDA levels, and evaluated apoptosis and intracellular reactive oxygen species (ROS) levels. The related proteins expression levels were monitored by Western blot. MCF-7 cells induced with H2O2 had a remarkable decrease in cell viability that was suppressed when it was interfered with PCB2 (0.1–10.0 μM). PCB2 interference memorably and dose-dependently inhibited H2O2- induced LDH leakage, ROS and MDA overproduction, while PCB2 markedly increased H2O2- induced the activities of SOD and GSH-Px. Eventually, H2O2 prominently down-regulated the ratio of Bcl-2/Bax and the relative proteins expression levels of Nrf2, GCLC, NQO1 and HO-1, and up-regulated the relative proteins expression levels of cytochrome c, caspase-3 and Keap1. However, the relative expression levels of these proteins were reversed in PCB2- interfered MCF-7 cells. This study implied that protective effect of PCB2 on H2O2- induced oxidative damage in MCF-7 cells might be related to inhibition of mitochondria-dependent apoptosis, activation of Keap1/Nrf2/HO-1 signaling pathway and improvement of the antioxidant enzymes activities.

A novel sintered metal fiber microfiltration of bio-ethanol fermentation broth

Qian Kang,Jan Baeyens,Tianwei Tan,Raf Dewil 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.8

In bio-ethanol fermentation, the broth consists of mainly water and ethanol, together with particulate residues of unreacted feedstock and additives (mostly yeast). Prior to further processing (distillation), and to avoid fouling of heat exchangers and distillation columns, the solids residues of the broth need to be removed to as low a concentration as possible. The current mechanical separation (belt filter or centrifuge) can only remove +10 μm particles representing about 90% of the total solids content. The remaining 10% is usually recovered in the bottom stream of the first distillation column, and forms the stillage that is further treated. To avoid fouling and even eliminate the first distillation column where the ethanol fraction is only increased from 12% (feed) to 16% (top), a better particulate removal is required. Novel sintered metal fiber (SFM) fleeces are highly efficient for microfiltration, and the removal of suspended solids largely exceeds 99%. The paper (i) positions microfiltration in the overall bio ethanol process; (ii) describes the novel sintered metal fiber microfiltration application; (iii) experimentally determines the major operating characteristics of SFM and (iv) predicts the up-scaled operation by using a simplified filtration model. At an ambient feed temperature, the flux of permeate exceeds 5m3/m2h for a TMP of 1.5 bar and a yeast concentration of 15 g/l, as commonly encountered in the fermenter broth.

Diversity of Pleurotus nebrodensis strains and detection a specific molecule marker

Qi Tan,C. Peter Romaine,Carl Schlagnhaufer,Mingjie Chen,Qian Guo,Jozsef Geml 한국버섯학회 2004 한국버섯학회 국제학술대회 Vol.3 No.-

Raman Lidar for the Measurement of Temperature, Water Vapor, and Aerosol in Beijing in the Winter of 2014

Min Tan,Zhen Shang,Chenbo Xie,Hui Ma,Qian Deng,Xiaomin Tian,Peng Zhuang,Zhanye Zhang,Yingjian Wang 한국광학회 2018 Current Optics and Photonics Vol.2 No.1

To measure atmospheric temperature, water vapor, and aerosol simultaneously, an efficient multi-function Raman lidar using an ultraviolet-wavelength laser has been developed. A high-performance spectroscopic box that utilizes multicavity interference filters, mounted sequentially at small angles of incidence, is used to separate the lidar return signals at different wavelengths, and to extract the signals with high efficiency. The external experiments are carried out for simultaneous detection of atmospheric temperature, water vapor, and aerosol extinction coefficient in Beijing, under clear and hazy weather conditions. The vertical profiles of temperature, water vapor, and aerosol extinction coefficient are analyzed. The results show that for an integration time of 5 min and laser energy of 200 mJ, the mean deviation between measurements obtained by lidar and radiosonde is small, and the overall trend is similar. The statistical temperature error for nighttime is below 1 K up to a height of 6.2 km under clear weather conditions, and up to a height of 2.5 km under slightly hazy weather conditions, with 5 min of observation time. An effective range for simultaneous detection of temperature and water vapor of up to 10 km is achieved. The temperature-inversion layer is found in the low troposphere. Continuous observations verify the reliability of Raman lidar to achieve real-time measurement of atmospheric parameters in the troposphere.

Grouting compactness monitoring of concrete-filled steel tube arch bridge model using piezoceramic-based transducers

Feng, Qian,Kong, Qingzhao,Tan, Jie,Song, Gangbing Techno-Press 2017 Smart Structures and Systems, An International Jou Vol.20 No.2

The load-carrying capacity and structural behavior of concrete-filled steel tube (CFST) structures is highly influenced by the grouting compactness in the steel tube. Due to the invisibility of the grout in the steel tube, monitoring of the grouting progress in such a structure is still a challenge. This paper develops an active sensing approach with combined piezoceramic-based smart aggregates (SA) and piezoceramic patches to monitor the grouting compactness of CFST bridge structure. A small-scale steel specimen was designed and fabricated to simulate CFST bridge structure in this research. Before casting, four SAs and two piezoceramic patches were installed in the pre-determined locations of the specimen. In the active sensing approach, selected SAs were utilized as actuators to generate designed stress waves, which were detected by other SAs or piezoceramic patch sensors. Since concrete functions as a wave conduit, the stress wave response can be only detected when the wave path between the actuator and the sensor is filled with concrete. For the sake of monitoring the grouting progress, the steel tube specimen was grouted in four stages, and each stage held three days for cement drying. Experimental results show that the received sensor signals in time domain clearly indicate the change of the signal amplitude before and after the wave path is filled with concrete. Further, a wavelet packet-based energy index matrix (WPEIM) was developed to compute signal energy of the received signals. The computed signal energies of the sensors shown in the WPEIM demonstrate the feasibility of the proposed method in the monitoring of the grouting progress.

Effects of Ambient Pressure and Injection Pressure on Diesel and Natural Gas Dual Fuel Spray

( Changsheng Shao ),( Qian Wang ),( Xiaoqiang Tan ) 한국액체미립화학회 2017 한국액체미립화학회 학술강연회 논문집 Vol.2017 No.-

Dual fuel engines operating with direct injected natural gas (NG) and pilot diesel has been attracted by many engine researchers. With this system, small quantities of diesel auto-ignite, and NG is then ignited by the pilot diesel flame. This stratified combustion technique provides better fuel economy and more efficient combustion, maintaining the power output of an equivalently-sized conventional diesel engine. Comparatively lower emissions of NOx and particulate matter were also recorded. For the further understanding of dual fuel spray, effects of ambient pressure and injection pressure on diesel and NG dual fuel spray are investigated. Both NG and diesel are directly injected into an optical constant volume chamber by a dual fuel injector combiner for different injection pressure and ambient pressure. Schlieren photography is used to visualize the development of dual fuel spray. A Matlab processing script was developed to extract useful qualitative and quantitative information from each video frame. A comparison is made between NG jet characteristics in single fuel model (SFM) and dual fuel model (DFM). Results shows that in both SFM and DFM, the tip penetration decreased with the increase of the ambient pressure and the decrease of NG injection pressure, while the cone angle increased with the increase of the ambient pressure and the decrease of NG injection pressure. At different ambient pressure, the diesel spray has little influence on NG tip penetration, however it has impact on NG cone angle. The cone angle in DFM is higher than that in SFM. With the increase of ambient pressure, the diesel spray has less impact on NG cone angle. At different NG injection pressure, the diesel spray has influence on both NG tip penetration and cone angle. With the increase of NG injection pressure, diesel spray has less impact on NG cone angle.