Modeling and Analysis of an Avionic Battery Discharge Regulator

Qian Chen,Haihong Yu,Xiaoming Huang,Yi Lu,Peng Qiu,Kai Tong,Jiazhuo Xuan,Feng Xu,Xiaohua Xuan,Weibo Huang,Yajing Zhang 전력전자학회 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

The avionic battery discharge regulator (BDR) plays an important role in a power-conditioning unit. With its merits of high efficiency, stable transfer function, and continuous input and output currents, the non-isolated Weinberg converter (NIWC) is suitable for avionic BDR. An improved peak current control strategy is proposed to achieve high current-sharing accuracy. Current and voltage regulators are designed based on a small signal model of a three-module NIWC system. The system with the designed regulators operates stably under any condition and achieves excellent transient response and current-sharing accuracy.

Distribution of nitrate and its implication for the contaminant source in groundwater of Huaibei Plain, Anhui Province

Jiazhong Qian,Lulu Wang,Yong Liu,Boren Wu,Xiaoming Wang 한국지질과학협의회 2015 Geosciences Journal Vol.19 No.3

High concentration of NO3-N in groundwater can pose risk to human’s health, thus the study of NO3-N contamination in groundwater is a very important issue related to public health. Using a typical agriculture zone, Huaibei plain in Anhui Province of China as a field site, the temporal and spatial variation of groundwater NO3-N concentration was studied using a multivariate statistical factor analysis combined with Kaiser-Meyer- Olkin method based on a hydrogeological investigation from 2005 to 2009 year. The results show: (1) The contaminant in the groundwater of Huaibei Plain in Anhui Province are serious. 10% of the shallow groundwater samples in non-rainy season of 2005 exceeds the recommended value of NO3-N by Chinese drinking water standard (≤20 mg/L), while 17.5% exceeds the recommended value (11.3 mg/L) by EC. (2) About 15% of shallow groundwater in the whole study area was polluted in 2005 with the maximum of 97.67 mg/L; Groundwater NO3-N concentration is higher in non-rainy season than in rainy season. And the NO3-N content in groundwater shows the increasing trend at all three depths sampled from 2005 to 2009 year. (3) Groundwater nitrate pollution mainly derives from anthropogenic activities in Huaibei Plain, Anhui Province. Further quantitative analysis need to be studied in the future.

Modeling and Analysis of an Avionic Battery Discharge Regulator

Chen, Qian,Yu, Haihong,Huang, Xiaoming,Lu, Yi,Qiu, Peng,Tong, Kai,Xuan, Jiazhuo,Xu, Feng,Xuan, Xiaohua,Huang, Weibo,Zhang, Yajing The Korean Institute of Power Electronics 2016 JOURNAL OF POWER ELECTRONICS Vol.16 No.3

The avionic battery discharge regulator (BDR) plays an important role in a power-conditioning unit. With its merits of high efficiency, stable transfer function, and continuous input and output currents, the non-isolated Weinberg converter (NIWC) is suitable for avionic BDR. An improved peak current control strategy is proposed to achieve high current-sharing accuracy. Current and voltage regulators are designed based on a small signal model of a three-module NIWC system. The system with the designed regulators operates stably under any condition and achieves excellent transient response and current-sharing accuracy.

Computing Pore Size Distribution in Non-woven Fibrous Filter Media

He Bai,Xiaoming Qian,Jintu Fan,Yao Qian,Yongchao Duo,Yongsheng Liu,Xiaobo Wang 한국섬유공학회 2020 Fibers and polymers Vol.21 No.1

Fundamental understanding of transport properties of non-woven fibrous material is depended on in dept cognitionof their microstructure. Non-woven fibrous filter media are formed by the random distribution of fibers in a specific spaceexhibit a complicated pore size structure. Computing pore size distribution (PSD) is a vital parameter in studying materialtransport dynamics. In this work, a theoretical model was suggested based on the gamma distribution and fiber orientationdistribution to predict the PSD in non-woven fibrous filter media. In parallel, the analytical model was compared with theprevious PSD theories and experimental results. The 3D virtual fiber structure was constructed by using GeoDict code, andthe pore size was represented by the inscribed circle diameter. Parameters influencing the PSD were studied, including fiberdiameter, porosity, and fiber orientation. Comparison of simulation results with analytical model was made. The resultsdemonstrate that the angle between the fiber and the Z-axis has little effect on the PSD. When the porosity is consistent,smaller pores can be formed by reducing fiber diameter. With the fiber diameter is constant, larger pores can be formed byincreasing the porosity.

Synthesis of Carbon Dots from PEG6000 and Papain for Fluorescent and Doxycycline Sensing

Yuanjiao Feng,Lihong Tan,Qian Tang,Wenwu Zhong,Xiaoming Yang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.09

Herein, a simple-green road for preparing carbon dots (CDs) from the mixture of PEG6000 and papain with approving fluorescence has been successfully developed for the first time. Meanwhile, the current CDs were characterized by analytical means such as fluorescence, UV visible spectrophotometer, HR-TEM, XPS and FTIR and so on. Afterwards, this kind of CDs were employed for analyzing doxycycline (DC) relying on the mechanism that the functional group of DC had interactions with CDs, hence, leading to the fluorescence quenching. Also, this DC analytical method mentioned here permitted in a linear range of 5.0 x 10 -8 mol/L - 5.0 x 10 -4 mol/L as well as a detection limit of 18nM at a signal-to-noise ratio (S/N) of 3. More importantly, the CDs prepared here were still explored for milk real samples, indicating their potential for broadening avenues towards other various applications.

Imposed drought effects on carbon storage of moso bamboo ecosystem in southeast China: results from a field experiment

Ge, Xiaogai,Zhou, Benzhi,Wang, Xiaoming,Li, Qian,Cao, Yonghui,Gu, Lianhong Springer Japan 2018 Ecological research Vol.33 No.2

<P><B>Abstract</B></P><P>Drought can severely affect carbon dynamics in forest ecosystems through impacts on carbon storage, reduced carbon fixation, abatement of the carbon sink function, and alteration of carbon sink‐source relationships. Currently, little is known about the effects of drought on the productivity and spatial patterns of carbon in bamboo forests. The objective of this study was to assess the effect of imposed drought on the carbon storage and soil carbon dynamics of a bamboo forest ecosystem in subtropical area of China. Drought was imposed via throughfall exclusion in moso bamboo forest from July 2012 to April 2013. Results indicated that bamboo shoots, new culms, shoot height, and diameter at breast height were significantly lower in throughfall exclusion (TE) plots than in control check (CK) plots, with decrease of 64.6, 70.8, 10.6 and 11.3%, respectively. Annual carbon sequestration for TE plots was 58.1% lower than that for CK plots. Soil carbon storage in the 0–60‐cm layer in CK and TE plots decreased by 3.7 and 12.2%, respectively, indicating that drought can decrease soil respiration by altering substrate availability. Ecosystem carbon storage increased by 4.75 t ha<SUP>−1</SUP> in CK plots but decreased by 13.71 t ha<SUP>−1</SUP> in TE plots. Our findings highlight that drought can reduce carbon storage and alter the spatial pattern of carbon in moso bamboo forest ecosystems, particularly when drought occurs during the development bamboo shoot. Our findings should provide a better understanding of carbon sequestration potential and aid determination of how future climate change may impact carbon budgets.</P>

Toughening of melamine–formaldehyde foams and advanced applications based on functional design

Bing Song,Xueli Zhu,Wei Wang,Liang Wang,Xiaoyuan Pei,Xiaoming Qian,Liangsen Liu,Zhiwei Xu 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.119 No.-

Owing to the intrinsic flame-retardancy, thermal stability, sound absorption, and easy processing, melamine–formaldehyde foams(MFs) have drawn substantial attention. Typically, the high-porosity and compressibilityof flexible MFs render them suitable for the construction of 3D templates and in thefabrication of porous N-doped carbon materials. But the widespread applications of MFs still suffer highbrittleness and low strength, calling for modifying and toughening MFs with more facile and economicalmethods, and much potential in advanced applications by functional design deserves further exploration. This review comprehensively summarized and evaluated the recent progress of the toughening methodsof MFs. We will also look into the applications of commercial MFs, carbonized MFs and foam-based compositesin flame retardancy and thermal management, oil/water separation, photothermal conversion,electrical energy storage, and other fields, aiming to give a guide for the preparation, modification, andexploitation of MFs both in traditional and emerging areas.