A Novel Dual-Input Boost-Buck Converter with Coupled Inductors for Distributed Thermoelectric Generation Systems

Junjun Zhang,Hongfei Wu,Kai Sun,Yan Xing,Feng Cao 전력전자학회 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.4

A dual-input boost-buck converter with coupled inductors (DIBBC-CI) is proposed as a thermoelectric generator (TEG) power conditioner with a wide input voltage range. The DIBBC-CI is built by cascading two boost cells and a buck cell with shared inverse coupled filter inductors. Low current ripple on both sides of the TEG and the battery are achieved. Reduced size and power losses of the filter inductors are benefited from the DC magnetic flux cancellation in the inductor core, leading to high efficiency and high power density. The operational principle, impact of coupled inductors, and design considerations for the proposed converter are analyzed in detail. Distributed maximum power point tracking, battery charging, and output control are implemented using a competitive logic to ensure seamless switching among operational modes. Both the simulation and experimental results verify the feasibility of the proposed topology and control.

A Novel Dual-Input Boost-Buck Converter with Coupled Inductors for Distributed Thermoelectric Generation Systems

Zhang, Junjun,Wu, Hongfei,Sun, Kai,Xing, Yan,Cao, Feng The Korean Institute of Power Electronics 2015 JOURNAL OF POWER ELECTRONICS Vol.15 No.4

A dual-input boost-buck converter with coupled inductors (DIBBC-CI) is proposed as a thermoelectric generator (TEG) power conditioner with a wide input voltage range. The DIBBC-CI is built by cascading two boost cells and a buck cell with shared inverse coupled filter inductors. Low current ripple on both sides of the TEG and the battery are achieved. Reduced size and power losses of the filter inductors are benefited from the DC magnetic flux cancellation in the inductor core, leading to high efficiency and high power density. The operational principle, impact of coupled inductors, and design considerations for the proposed converter are analyzed in detail. Distributed maximum power point tracking, battery charging, and output control are implemented using a competitive logic to ensure seamless switching among operational modes. Both the simulation and experimental results verify the feasibility of the proposed topology and control.

Three-dimensional WO3 nanorod arrays on Si as photoanodes for efficient photoelectrochemical water splitting

Junjun Zhang,Cu Dang Van,Kuniharu Takei,Min Hyung Lee 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.124 No.-

Arrays of WO3–Si forest hierarchical structures have been successfully synthesized by growing WO3nanorod on the surface of vertically aligned n-Si micropillar arrays using a chemical vapor depositiontechnique. The three-dimensional (3D) WO3–Si nanorod forest improves photoelectrochemical performances;it exhibits higher photocurrent density and a more negative onset potential of 0.5 V vs. reversiblehydrogen electrode compared with the WO3 nanorod array on planar Si substrate. More importantly,this directly grown 3D hierarchical structure exhibits extraordinary stability for water oxidation withnegligible losses of photoactivity for 24 h in a neutral pH solution. The enhanced photostability is attributednot only to the formation of O vacancies in WO3, which is resistive to photocorrosion but also themultiple internal reflection in 3D hierarchical structure. Our work demonstrates the importance of structuralinnovation in improving solar water efficiency.

BERT 및 계층 그래프 컨볼루션 신경망 기반 감성분석 모델

장쥔쥔(Junjun Zhang),신종호(Jongho Shin),안수빈(Suvin An),박태영(Taeyoung Park),노기섭(Giseop Noh) 한국정보통신학회 2022 한국정보통신학회 종합학술대회 논문집 Vol.26 No.2

EFFECTS OF WATER INJECTION ON COMBUSTION EMISSION AND KNOCK CHARACTERISTICS OF TURBOCHARGED DIRECT INJECTION GASOLINE ENGINE

Fuwu Yan,Junjun Wang,Dong Yan,Wenlong Zhang,Guoqing Zhang,Jizhou Zhang,Ziyi Chen,Yu Wang 한국자동차공학회 2022 International journal of automotive technology Vol.23 No.4

This paper studied the effects of water injection on combustion, emissions and knock. The results showed that direct water injection (DWI) absorbed more heat than inlet port water injection (PWI), resulting in lower cylinder pressure, higher oxygen content and longer combustion duration. And the turbulence kinetic energy of DWI model was greater, resulting in lower soot and CO emissions of DWI. Furthermore, the cooling effect of exhaust port side WI was better than intake port side, which reduced NOX emission. Besides, the injection pressure of single injector WI was higher than double injector, which increased the combustion duration and reduced the cylinder pressure. The decrease of temperature under water dilution was the main reason for the reduction of NOX, while the increase of incomplete combustion increased the soot and CO emission. Finally, with the same amount of WI, the knock suppression effect of DWI models was better than PWI models. The knock intensity (KI) of all models decreased gradually with the increase of water, and DWI models decreased more rapidly. For PWI models, when the amount of water became smaller, the engine pressure fluctuation of certain areas in the cylinder increased slightly, weakening the influence of WI on engine knock.

High-Conductivity SiO2-Matrix B-Doped Si-NC Thin Films by Following Ion-Beam Treatment

Junjun Huang,Weiyan Wang,Jie Yang,Yongzhen Tan,Wei Chen,Tianyu Ge,Yajun Zhang,Min Gao,Zhenming Chen 대한금속·재료학회 2016 ELECTRONIC MATERIALS LETTERS Vol.12 No.6

In this work, further ion-beam was performed on SiO2-matrix B-doped Si-NC (SBC) thin films in order to enhance conductivity. The effect of ionbeamtype on the electrical properties of SBC thin films was investigatedsystematically. The results indicated that the conductivities of SBC thinfilms were significantly improved by both argon and hydrogen ion-beamtreatments, and the higher the hydrogen ion ratio, the higher theconductivity of SBC thin films. The conductivity of SBC thin films wasincreased from 1.82 × 10−6 S/cm to 3.2 × 10−3 S/cm with followinghydrogen-ion-beam treatment. The change in conductivity of SBC thinfilms was most possibly resultant from the ion-beam treatment facilitatingthe formation of higher superficial order and lower defects. An alternativemethod was proposed to prepare high-conductivity SBC thin films, whichmay be applied to other heterogeneous thin films.

A methylprednisolone-loaded and core-shell nanofiber-covered stent-graft to prevent inflammation and reduce degradation in aortic dissection

Junjun Liu,Hongqiao Zhu,Yifei Pei,Heng Zhang,Jian Zhou,Zaiping Jing 한국생체재료학회 2022 생체재료학회지 Vol.26 No.2

Background: Stent-graft-induced inflammation is an independent risk factor for adverse aortic remodeling in aortic dissection. In this context, we asked that whether a methylprednisolone-loaded stent-graft could reduce inflammation and degradation. Methods: First, a coaxial electrospinning technique was used to create a core-shell film with methylprednisolone encapsulated in the inner of poly (L-lactide-co-caprolactone) nanofibers for controllable drug release. Second, an in vitro study was conducted to evaluate the biocompatibility of the nanofiber meshes. Third, the porcine aortic dissection model was developed to investigate the therapeutic effects of the ethylprednisolone-loaded stent-graft. Results: The results demonstrated that the nanofiber-coated film with a methylprednisolone-poly-caprolactone core layer and a poly (L-lactide-co-caprolactone) shell layer could effectively sustain drug release in vitro. In vivo study showed that the methylprednisolone-loaded stent-graft could reduce degradtion of aortic dissection by regulating inflammation. Conclusions: Overall, the controllable drug release by coaxial nanofiber is a promising approach to alleviate aortic inflammation and promote aortic remodeling after stent-graft implantation.

Understanding the friction behavior of sulfur-terminated diamond-like carbon films under high vacuum by first-principles calculations

Renhui Zhang,Juan Zhao,Yingchang Yang,Wei Shi,Zhibin Lu,Junjun Wang 한국물리학회 2018 Current Applied Physics Vol.18 No.3

Generally, the repulsive force was a key factor account for superlow friction of H or F doped diamond-like carbon (DLC) films under high vacuum. As we known, H or F doped DLC usually exhibited superlow friction under high vacuum. However, the superlow friction of S doped DLC under high vacuum was not found so far. This phenomenon was desirable to be well investigated. In this work, S-terminated diamond interfaces also exhibited strong repulsive force, however, the estimated friction coefficient was variable for S-terminated diamond interfaces. The lowest and largest friction coefficient was about 0.003 and 0.4 respectively, which indicated that the superlow friction of S doped DLC could achieve in theory. In order to well probe the unusual friction behavior of S doped DLC under high vacuum, using first-principles method, the repulsive interaction between sliding surfaces was well investigated in order to understand the unusual friction behavior of S doped DLC films.

Identification of HvLRX, a new dehydration and light responsive gene in Tibetan hulless barley (Hordeum vulgare var. nudum)

Liang Junjun,Zhang Haili,Yi Ling,Tang Yawei,Long Hai,Yu Maoqun,Deng Guangbing 한국유전학회 2021 Genes & Genomics Vol.43 No.12

Background Tibetan hulless barley (Hordeum vulgare var. nudum), adjusting to the harsh environment on Qinghai–Tibet Plateau, is a good subject for analyzing drought tolerance mechanism. Several unannotated diferentially expressed genes (DEGs) were identifed through our previous RNA-Seq study using two hulless barley accessions with contrasting drought tolerance. One of these DEGs, HVU010048.2, showed up-regulated pattern under dehydration stress in both drought tolerant (DT) and drought susceptible (DS) accessions, while its function in drought resistance remains unknown. This new gene was named as HvLRX (light responsive X), because its expression was induced under high light intensity while suppressed under dark. Objective To provide preliminary bioinformatics prediction, expression pattern, and drought resistance function of this new gene. Methods Bioinformatics analysis of HvLRX were conducted by MEGA, PlantCARE, ProtParam, CELLO et al. The expression pattern of HvLRX under diferent light intensity, dehydration shock, gradual drought stress, NaCl stress, polyethylene glycol (PEG) 6000 stress and abscisic acid (ABA) treatment was investigated by quantitative reverse transcription-polymerase chain reaction (RT-qPCR). The function of HvLRX was analyzed by virus induced gene silencing (VIGS) in hulless barley and by transgenic method in tobacco. Results Full cDNAs of HvLRX were cloned and compared in three hulless barley accessions. Homologues of HvLRX protein in other plants were excavated and their phylogenetic relationship was analyzed. Several light responsive elements (ATC-motif, Box 4, G-box, Sp1, and chs-CMA1a) were identifed in its promoter region. Its expression can be promoted under high light intensity, dehydration shock, gradual drought stress, PEG 6000, and NaCl stress, but was almost unchanged in ABA treatment. HvLRX-silenced plants had a higher leaf water loss rate (WLR) and a lower survival rate (SR) compared with controls under dehydration stress. The infected leaves of HvLRX-silenced plants lost their water content quickly and became withered at 10 dpi. The SR of HvLRX overexpressed transgenic tobacco plants was signifcantly higher than that of wild-type plants. These results indicated HvLRX play a role in drought resistance. Besides, retarded vegetative growth was detected in HvLRX-silenced hulless barley plants, which suggested that this gene is important for plant development. Conclusions This study provided data of bioinformatics, expression pattern, and function of HvLRX. To our knowledge, this is the frst report of this new dehydration and light responsive gene.

Intraoperative frozen pathology exam of Common iliac lymph nodes and Para-Aortic lymphadenectomy on the prognosis and quality of life for patients with IB2-IIA2 Cervical Cancer: trial protocol for a randomized controlled trial (C-PACC trial)

Xinyu Qu,Junjun Qiu,Lili Jiang,Xiaorong Qi,Guonan Zhang,Weiwei Feng,Yudong Wang,Yincheng Teng,Xipeng Wang,Xiaoqing Guo,Keqin Hua 대한부인종양학회 2023 Journal of Gynecologic Oncology Vol.34 No.2

Background: The impact of para-aortic lymphadenectomy (PALD) on prognosis and quality of life (QoL) for IB2-IIA2 cervical cancer patients remain controversial. And whether intraoperative frozen pathology exam on common iliac lymph nodes could help predict para-aortic lymph node (PALN) metastasis was unanswered with high-level evidence. Methods: A multi-center, randomized controlled study is intended to investigate the effect of PALD on the prognosis and QoL in cervical cancer patients and to assess the value of intraoperative frozen pathological evaluation of common iliac nodes metastasis for the prediction of PALN metastasis. After choosing whether to receive intraoperative frozen pathological examination of bilateral common iliac lymph nodes, eligible patients will be randomly assigned (1:1) to receive PALD or not. The primary end point is 2-year progression-free survival (PFS). The secondary end points include 5-year PFS, 2-year overall survival (OS), 5-year OS, adverse events (AEs) caused by PALD, AEs caused by radiotherapy and QoL. A total of 728 patients will be enrolled from 8 hospitals in China within 3-year period and followed up for 5 years.