Comparative Study of Power Loss and Thermal Performance in Five-Phase FSCWPM Machine With/Without Third Harmonic Current Injection

Chen Haijun,Guo Tengteng,Zhang Lufeng 대한전기학회 2021 Journal of Electrical Engineering & Technology Vol.16 No.4

Five-phase fractional slot concentrated winding permanent magnet (FSCWPM) machine with equal/unequal stator teeth can improve the torque density by added third harmonic current injection (Sin + 3rd). However, the injection of the third harmonic current will change the stator, rotor, and PM losses, and thus the thermal distribution. Therefore, it is necessary to conduct a comparative study on the losses and the thermal performances of the fi ve-phase FSCWPM machine with the sine current supply and Sin + 3rd current supply. In this paper, the structures of the fi ve-phase FSCWPM machines with equal/ unequal stator teeth are illustrated, and their losses characteristic at diff erent rotating speeds including copper loss, PM loss, and iron-core loss are comparatively analyzed under the same output torque constraint. Then, their thermal distributions are investigated based on the coupling of electromagnetic-thermal calculation of the 3D fi nite element (FE) method. The results demonstrate that the fi ve-phase FSCWPM machines energized with the Sin + 3rd current have a better thermal performance at a low rotating speed, especially the fi ve-phase FSCWPM machine with unequal stator teeth. Furthermore, the thermal experiment concerning a fi ve-phase FSCWPM machine with unequal stator teeth is conducted to verify the validity of the related analysis.

Preparation and characterization of epoxidized microbial oil

Xinde Chen,Dan Yang,Lian Xiong,Bo Wang,Xuefang Chen,Can Wang,Hairong Zhang,Haijun Guo 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.3

The potential of microbial oil derived from yeasts through fermentation using crops biomass for the formation of plasticizers was investigated. Plasticizers were formed via epoxidation reaction. Five factors of the orthogonal experiment (reaction temperature, time, weight ratio of H2O2/MO, H2SO4/MO, and HCOOH/MO) have been used for optimization of parameters. To further enhance the iodine value of microbial oil and increase the epoxy value of the epoxide, an amount of soybean oil was added. The products were characterized by FTIR, 13C-NMR and 1H-NMR. Under the optimum condition, the epoxy value and the iodine value of epoxide product were 6.21% and 1.8 g I2/100 g with a yield of 91.86% at an oil conversion of 98.43%. This study successfully demonstrated the conversion of crops biomass into value-added chemicals using simple and conventional chemical reactions.

9.73% Efficiency Nonfullerene All Organic Small Molecule Solar Cells with Absorption-Complementary Donor and Acceptor

Bin, Haijun,Yang, Yankang,Zhang, Zhi-Guo,Ye, Long,Ghasemi, Masoud,Chen, Shanshan,Zhang, Yindong,Zhang, Chunfeng,Sun, Chenkai,Xue, Lingwei,Yang, Changduk,Ade, Harald,Li, Yongfang American Chemical Society 2017 JOURNAL OF THE AMERICAN CHEMICAL SOCIETY - Vol.139 No.14

<P>In the last two years, polymer solar cells (PSCs) developed quickly with n-type organic semiconductor (n-OSs) as acceptor. In contrast, the research progress of nonfullerene organic solar cells (OSCs) with organic small molecule as donor and the n-OS as acceptor lags behind. Here, we synthesized a D-A structured medium bandgap organic small molecule H11 with bithienyl-benzodithiophene (BDTT) as central donor unit and fluorobenzo-triazole as acceptor unit, and achieved a power conversion efficiency (PCE) of 9.73% for the all organic small molecules OSCs with H11 as donor and a low bandgap n-OS IDIC as acceptor. A control molecule H12 without thiophene conjugated side chains on the BDT unit was also synthesized for investigating the effect of the thiophene conjugated side chains on the photovoltaic performance of the p-type organic semiconductors (p-OSs). Compared with H12, the 2D-conjugated H11 with thiophene conjugated side chains shows intense absorption, low-lying HOMO energy level, higher hole mobility and ordered bimodal crystallite packing in the blend films. Moreover, a larger interaction parameter (chi) was observed in the H11 blends calculated from Hansen solubility parameters and differential scanning calorimetry measurements. These special features combined with the complementary absorption of H11 donor and IDIC acceptor resulted in the best PCE of 9.73% for nonfullerene all small molecule OSCs up to date. Our results indicate that fluorobenzotriazole based 2D conjugated p-OSs are promising medium bandgap donors in the nonfullerene OSCs.</P>

Controlled Synthesis of FeSe2 Nanoflakes Toward Advanced Sodium Storage Behavior Integrated with Ether-Based Electrolyte

Yalan Chen,Jingtong Zhang,Haijun Liu,Zhaojie Wang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.12

Sodium ion batteries based on the more sodium source reserve than that of lithium have been designed as promising alternatives to lithium ion batteries. However, several problems including unsatisfied specific capacity and serious cyclic stability must be solved before the reality. One of the effective approaches to solve the abovementioned problems is to search for suitable anode materials. In this work, we designed and prepared FeSe2 nanoflakes via a simple hydrothermal method which can be adjusted in composition by Fe precursor. As a potential anode for sodium storage, the optimized FeSe2 electrode was further evaluated in different electrolytes of NaClO4 in propylene carbonate/fluoroethylene carbonate and NaCF3SO3 in diethylene glycol dimethyl ether. The capacity was about 470 mA h g-1 and 535 mA h g -1 at 0.5 Ag-1, respectively, in the voltage between 0.5V and 2.9V in the cycle of stabilization phase. Superior performance both in capacity and in stability was obtained in ether-based electrolyte, which affords the property without plugging the intermediates of transition metal dichalcogenides during charge/discharge processes.

Fully Distributed Event-triggered Semi-global Consensus of Multi-agent Systems with Input Saturation and Directed Topology

Siyu Chen,Haijun Jiang,Zhiyong Yu 제어·로봇·시스템학회 2019 International Journal of Control, Automation, and Vol.17 No.12

This paper studies the consensus problem of multi-agent systems with input saturation and directed communication topology, by utilizing the low-gain feedback method and the event-triggered control laws. Two event-triggered control laws, the centralized and the distributed laws, are proposed to guarantee semi-global consensus of the multi-agent systems. Then, a sufficient condition is presented to prove strictly positive low bound of inner-event time, i.e., the Zeno behavior can be avoided. Finally, the effectiveness of the proposed event-triggered laws is further verified by an example.

Piperazine-activated diethanolamine formulation for post-combustion CO2 capture

Bisweswar Das,Haijun Guo,Lian Xiong,Bishnupada Mandal,Arindam Modak,Kamal Kishore Pant,Xinde Chen 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.118 No.-

Although activated alkanolamine based solvents had great potential for energy-efficient post-combustionCO2 capture, yet these suffers from disadvantageous due to high capital cost of the process. In thisresearch we developed and discussed the overall reaction scheme between CO2 and activated solvents. We investigated the kinetics of CO2 into piperazine (PZ) activated aqueous diethanolamine (DEA) bywetted-wall column contactor at (298–323) K, (5–15) kPa and fixed 3.0 kmol∙m3. Physicochemical propertiesof such systems were determined while detailed uncertainty analysis were conducted. In thermodynamicspoint of view, liquid–liquid interaction were explored and evaluated by related parameters. The kinetics rate parameters for such activated solvents were interpreted based on kinetic study affordingto the pseudo-first-order reaction method. At various temperature, kov of (PZ + DEA + H2O) were considerablylarger than reported (AMP + PZ + H2O) systems. The results of kinetics study demonstrated thatrate of CO2 in solvents were enhanced substantially as compared to DEA due to the addition of low quantity(0–0.45 kmol∙m3) PZ into solvents. Besides, physicochemical properties were measured in terms ofdifferent models with absolute average deviation (AAD) < 5 %. Ultimately, (PZ + DEA + H2O) may be consideredas vital solvents in amine scrubbing due to lower energy requirement for CO2 capture comparedto (PZ + MEA + H2O).

中国社交媒体环境下“宝妈创业者”的职业叙述:自我、孩子与生意

王翼伟(Yiwei Wang),陈海俊(Haijun Chen) YIXIN 출판사 2023 Journal of China Studies Vol.1 No.3

在过去的二十年里,伴随着信息技术的快速发展,女性创业者在全球大幅增加,这些创业者中有很大一部分是把创业和抚养子女结合起来的母亲,也被称为“宝妈创业者”(mompreneurs)。有研究者强调了人生关键阶段的变化对母亲职业决策的影响,并指出“妈妈角色”对于她们职业发展模式的特殊影响。尽管人们对女性职业生涯发展和创业的兴趣日益浓厚,但对一边养育幼年子女一边创业的自雇母亲的创业生涯的研究却相对较少。本研究采用职业叙述的研究方法和定性访谈的研究设计,主要基于“万花筒职业模式”,旨在探索“宝妈创业者”如何看待和协调“自我”“孩子”和“生意”三者之间的关系。作为访谈对象的12位母亲是中国最普通的宝妈创业者的小样本,采用目的性抽样和滚雪球抽样方法进行招募。该研究提出了“六种创业职业类型”来解释母亲为什么会转变为创业者,并致力于为从事女性创业和职业咨询的研究人员和从业者提供理论和实践参考。 In the past decades, women-owned businesses have increased significantly. A large portion of these entrepreneurs are mothers who combine entrepreneurship with raising their children and are also known as ‘mompreneurs’. Researchers have highlighted the impact of changes at critical life stages on mothers’ career decisions, and noted that the unique way that entrepreneurial mothers coordinate roles, relationships, and domain involvement has an important influence on their career patterns. Despite a growing interest in women’s career-life development and entrepreneurship, relatively few researches have been conducted on the entrepreneurial career of self-employed mothers with dependent children. This research seeks to understand how mompreneurs perceive the relationship between self, business, and children. Adopting a career narrative perspective, this study applies a qualitative interview research design, the data were collected through open-ended, semi-structured interviews by face to face or Skype, supplemented by questionnaire. The twelve mothers’ interviews were a small sample of the most ordinary mompreneurs in China, they were recruited by purposive sampling and snowball sampling method. The study proposes ‘six entrepreneurial career types’ to explain why mother mothers’ transit into entrepreneurship, and is dedicated to providing theoretical and practical references for researchers and practitioners engaged in female entrepreneurship and career counseling.

A Wrapper for Extracting Information Records from Forums based on Page Segmentation

Chunshan Li,Jingjing Chen,Dianhui Chu,Ge Song,Haijun Zhang,Yunming Ye,Jianliang Xu 보안공학연구지원센터 2014 International Journal of Database Theory and Appli Vol.7 No.4

miR-582-5p inhibits migration and chemo-resistant capabilities of colorectal cancer cells by targeting TNKS2

Xiao Weixing,Zhou Haijun,Chen Bingrong,Shen Bin,Zhou Jun 한국유전학회 2022 Genes & Genomics Vol.44 No.6

Background: Metastasis and chemo-resistance are still important factors that limit the overall efficacy of colorectal cancer treatment. Understanding the detailed molecular mechanism and identifying potential biomarkers are of great value in prognosis prediction and risk stratification. Objective: We investigated the role of miR-582-5p in colorectal cancer pathogenesis, progression and chemo-resistance. Furthermore, we explored the underlying molecular mechanism of miR-582-5p in modulation of malignant behaviors of colorectal cancer cells. Methods: Clinical samples and colorectal cancer cell lines were applied to explore miR-582-5p expression level and its significance on tumor cell metastasis and chemo-resistance. Transwell study and cellular survivability study were performed to explore the influences of miR-582-5p expression modulation on tumor cell chemo-resistance and invasion/migration. Dual-luciferase reporter gene assay was conducted to explore the influences of miR-582-5p on its target gene TNKS2. Results: Colorectal cancer patients with lymph node or distal organ metastatic diseases exhibited significantly lower level of miR-582-5p. In vitro studies have indicated that miR-582-5p inhibition significantly increased migration and chemo-resistant capabilities of tumor cells. And dual-luciferase reporter gene assay demonstrated that miR-582-5p exhibited its influences on the biological behavior of tumor cells by targeting TNKS2. Conclusions: Our study demonstrated for the first time that miR-582-5p played an important role for colorectal tumor cell metastasis and chemo-resistance. Our research also indicated that miR-582-5p and its target gene TNKS2 could be novel biomarkers for metastatic disease prediction, overall prognosis evaluation, as well as potential therapeutic target for colorectal cancer patients.

Purification of pickling wastewater from the steel industry using membrane filters: Performance and membrane fouling

Jinfeng Zhang,Guanyi Chen,Yanning Ma,Miao Xu,Songyan Qin,Xiaoliang Liu,Haijun Feng,Lian Hou 대한환경공학회 2022 Environmental Engineering Research Vol.27 No.1

A new technique for treating pickling wastewater discharged from the steel industry using membrane filters was developed and membrane fouling was characterized in a full scale membrane filter. The morphological and chemical properties were examined through scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive X-ray spectroscopy (EDS) and inductively coupled plasma optical emission spectroscopy (ICP-OES) etc. The results showed that inorganic elements such as phosphates, chlorides, and sulfates were severely blocked in membrane surfaces and pores. The porosity, permeability, hydrophilic contact angle, and surface charge capacity of fouled membranes were all lower than those of new membranes, while the optimal neutralization reaction pH region for fouled membranes shifted and narrowed. Charge neutralization is a critical reason to membrane fouling. By increasing the Zeta potential of the pickling wastewater, the membrane fouling could be controlled. This method is proven to effectively improve the separation property of precipitates after pickling wastewater was neutralized. Moreover, Neutralization helped to reduce the unit number of treatment processes. This investigation could assist in obtaining a better understanding of the fouling properties and behavior in the full-scale membrane filters in the pickling wastewater treatment.