Optimization and fabrication of a planar thermoelectric generator for a high-performance solar thermoelectric generator

Shen Haishan,이후정,한승우 한국물리학회 2021 Current Applied Physics Vol.22 No.-

A planar thermoelectric generator (TEG) could be used as an energy harvester for wireless sensor networks (WSNs). Its planar configuration offers the advantages of miniaturization and low-cost fabrication. Herein, we report the fabrication of a device based on a co-evaporated thick film of Bi–Te. Before fabrication we studied quantitative optimization dimensions for the planar TEG via finite element method (FEM) simulations. The planar TEG was also used in a high-performance solar thermoelectric generator (STEG) that concentrated heat from solar radiation via a solar absorber to generate a temperature difference (ΔT) between two thermoelectric and electrode junctions. When exposed to a solar simulator, the STEG produced a ΔT of about 6 ◦C and generated 2.3 μW of power. The demonstrated high flexibility and mechanical stability of this device suggests applications in wearable electronics.

Thickness dependence of the electrical and thermoelectric properties of co-evaporated Sb₂Te₃ films

Shen, Haishan,Lee, Suhyeon,Kang, Jun-gu,Eom, Tae-Yil,Lee, Hoojeong,Han, Seungwoo Elsevier 2018 APPLIED SURFACE SCIENCE - Vol.429 No.-

<P><B>Abstract</B></P> <P>P-type antimony telluride (Sb<SUB>2</SUB>Te<SUB>3</SUB>) films of various thicknesses (1-, 6-, 10-, and 16-μm) were deposited on an oxidized Si (100) substrate at 250°C by effusion cell co-evaporation. Microstructural analysis using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy revealed that the grains of the films grew in a mode in which recrystallization was prevalent and grain growth subdued, in contrast to typical film growth, which is often characterized by grain growth. The resultant microstructure exhibited narrow columnar grains, the preferred orientation of which changed with film growth thickness from (1010) with the 1-μm films to (015) for the 6- and 10-μm films, and finally (110) for the 16-μm films. Carrier mobility and the overall thermoelectric properties of the Sb<SUB>2</SUB>Te<SUB>3</SUB> films were affected significantly by changes in the film microstructure; this was attributed to the strong anisotropy of Sb<SUB>2</SUB>Te<SUB>3</SUB> regarding electrical conductivity. The highest power factor of 3.3mW/mK<SUP>2</SUP> was observed for the 1-μm-thick Sb<SUB>2</SUB>Te<SUB>3</SUB> film.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Sb<SUB>2</SUB>Te<SUB>3</SUB> films of varying thicknesses were fabricated using co-evaporation. </LI> <LI> Changes in the growth texture of the films have a significant effect on the properties. </LI> <LI> The mobility decreased with increasing film thickness. </LI> <LI> The Seebeck coefficient decreased only slightly with increasing film thickness. </LI> <LI> The 1-μm-thick Sb<SUB>2</SUB>Te<SUB>3</SUB> film possess the largest power factor. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Top and cross-sectional scanning electron microscopy images of 1-, 6-, 10-, and 16-μm-thick Sb2Te3 film samples, and schematic illustrations of micron-thick Sb2Te3 film growth: \(a) typical columnar growth and (b) growth of 16-μm thick film sample.</P> <P>[DISPLAY OMISSION]</P>

Thickness effects on the microstructure and electrical/thermoelectric properties of co-evaporated Bi-Te thin films

Shen, Haishan,Lee, Suhyeon,Kang, Jun-gu,Eom, Tae-Yil,Lee, Hoojeong,Kang, Chiwon,Han, Seungwoo Elsevier 2018 Journal of alloys and compounds Vol.767 No.-

<P><B>Abstract</B></P> <P>In this study, we investigated the effect of film thickness on the electrical and thermoelectric properties of bismuth-tellurium (Bi-Te) films. Bi-Te films of 1-, 4-, 10-, and 18-μm thicknesses were deposited via co-evaporation. Microstructural analyses using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy indicated columnar film growth, with a highly porous structure that increased with the film thickness. The electron mobility of the films decreased significantly as the film thickness increased, which may be explained by the film porosity. Given a fairly constant Seebeck coefficient, the power factor decreased significantly with film thickness: 2.8 mW/mK<SUP>2</SUP> for the 1-μm-thick film and 1.5 mW/mK<SUP>2</SUP> for the 18-μm-thick Bi-Te film.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We investigate the effects of the film thickness of Bi-Te films the electrical and thermoelectric properties. </LI> <LI> We deposit Bi-Te films with 1-, 4-, 10-, 18-μm thicknesses via co-evaporation. </LI> <LI> The electron mobility decreases significantly with the thickness increasing. </LI> <LI> With the Seebeck coefficient not changing much, the power factor decreases substantially with the thickness. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Securing the Road Ahead: Blockchain for Enhanced Trust and Security in V2X Communication

Razafimanjato Mahalinoro,Haishan Yang,Donghyun Jeon,Bomi Jeong,Dongkyun Kim 한국통신학회 2024 한국통신학회 학술대회논문집 Vol.2024 No.1

Remote Identification for Smart-meter Operation Error based on a Wireless Sensor Network in a Smart City

Wenyu Liu,Haishan Zhou,Muxin Zhang,Ying Shang,Yudan Liu 대한전자공학회 2022 IEIE Transactions on Smart Processing & Computing Vol.11 No.6

This paper presents a remote identification method for smart-meter operation errors based on a wireless sensor network (WSN) in a smart city to reduce the bad operation of smart meters. In the WSN, ZigBee communication technology was used to collect data from smart meters to enhance the reliability of information. The LEACH protocol can effectively extend the network life cycle and was selected as a communication protocol for WSNs to collect operation data from intelligent meters. Based on the operation data of a smart meter collected by a WSN, a remote identification model of operation error of a smart meter was established. The limited memory least square algorithm was adopted to construct the remote identification model of operation error for a smart meter to realize the remote identification of a smart-meter error in a smart city. The proposed method can use a WSN to collect operation data from a smart meter and remotely identify the mean absolute percentage error (MAPE) and root mean square error (RMSE) of a smart meter’s operation error, which were less than 1%.

Proteome Analysis Provides New Insight into Major Proteins Involved in Gibberellin-induced Fruit Setting in Triploid Loquat (Eriobotrya japonica)

Shuang Jiang,Haishan An,Fangjie Xu,Xueying Zhang 한국유전학회 2020 Genes & Genomics Vol.42 No.4

Background Parthenocarpy can be induced by gibberellin (GA) treatment in plants. The fruits of the loquat exhibit many seeds. GA treatment can induce the development of seedless fruit and increase fruit quality during production. However, the molecular mechanism of fruit setting under GA treatment is still unclear. Objective Our aim was to explore GA-induced parthenocarpy in triploid loquat by proteome analysis to identify the differentially expressed proteins. Methods A proteome analysis was performed using TMT protein labeling and LC-MS/MS in triploid loquat. Results A total of 7290 protein groups were identified in the two stages of fruit setting. The quantitative results showed that 923 differentially expressed proteins (DEPs) were isolated, which were enriched in five pathways: ribosome, citrate cycle (TCA cycle), pentose phosphate, carbon metabolism, and carbon fixation. Twenty-four DEPs were annotated as putative key regulatory proteins involved in fruit setting, which were related to the auxin response, gibberellin metabolism, ethylene synthesis, and cell division. In addition, thirty-five DEPs were involved in the formation of the cell wall, which might be downstream proteins involved in cell proliferation during fruit setting. Conclusion Our report reveals new insight into the protein dynamics of loquat fruit setting induced by GA treatment via the analysis of proteome profiles and provides a reference for other Rosaceae species.

Sensitivity Experiments of the Local Wildland Fire with WRF-Fire Module

Lai Shaojun,Chen Haishan,He Fen,Wu Weijie 한국기상학회 2020 Asia-Pacific Journal of Atmospheric Sciences Vol.56 No.4

In this paper, it is discussed the performance of theWeather Research and Forecasting (WRF) model coupled with a wildland firebehavior module (WRF-Fire model) by the observational data collected in an experiment with a low-intensity prescribed fire (LIPF) conducted in the New Jersey Pine Barrens (NJPB) on March 6, 2012. The sensitivity experiments of theWRF-Fire model are carried out to investigate the interactions between the wildland fire and the atmospheric planetary boundary layer. The twoway WRF-Fire model conofigured with fire and large eddy simulation (LES) mode is used to explore the fire characteristics of perimeter shape, intensity, spread direction and external factors ofwind speed, and to discuss how these external parameters affect the fire, and the interactions between the atmosphere and fire. Results show that the sensitive experiments can provide the meteorological elements close to observations, such as the temperatures, winds and turbulent kinetic energy near the surface in the vicinity of the fire. The simulations also can reproduce the fire spread shape and speed, fire intensity, and heat flux released from fire. From the view of energy, the heat flux feed back to the atmospheric model and heat the air near the surface, which will induce strong thermal and dynamic instability causing strong horizontal convergence and updraft, and form the fire-induced convective boundary layer. The updraft will be tilted downstream of the fire area based on the height of the ambient winds. Due to the effect of the this updrafts, the particles and heat from the fuel combustion can be transported to the downwind and lateral regions of the fire area. Meanwhile, there is a downdraft flow with higher momentum nearby the fire line transporting fresh oxygen to the near surface, which will increase winds behind the fire line, accelerate the rate of spread (ROS) and make the fire spread to a larger area. Ultimately, a fire-induced climate is established.

Enabling Vessel Collision-Avoidance Expert Systems to Negotiate

Qinyou Hu,Chaojian Shi,Haishan Chen,Qiaoer Hu 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.1 No.-

Automatic vessel collision-avoidance systems have been studied in the fields of artificial intelligence and navigation for decades. And to facilitate automatic collision-avoidance decision-making in two-vessel-encounter situation, several expert and fuzzy expert systems have been developed. However, none of them can negotiate with each other as seafarers usually do when they intend to make a more economic overall plan of collision avoidance in the COLREGS-COST-HIGH situations where collision avoidance following the International Regulations for Preventing Collisions at Sea(COLREGS) costs too much. Automatic Identification System(AIS) makes data communication between two vessels possible, and negotiation methods can be used to optimize vessel collision avoidance. In this paper, a negotiation framework is put forward to enable vessels to negotiate to optimize collision avoidance in the COLREGS-COST-HIGH situations at open sea. A vessel vector space is defined and therewith a cost model is put forward to evaluate the cost of collision-avoidance actions. Negotiations between a give-way vessel and a stand-on vessel and between two give-way vessels are considered respectively to reach overall low cost agreements. With the framework proposed in this paper, two vessels involved in a COLREGS-COST-HIGH situation can negotiate with each other to get a more economic overall plan of collision avoidance than that suggested by the traditional collision-avoidance expert systems.

Improving the Machining Quality of Micro Structures by Using Electrophoresis-Assisted Ultrasonic Micromilling Machining

Junfeng He,Zhongning Guo,Haishan Lian,Junjie Wang,Xiaolei Chen,Jiangwen Liu 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.7 No.1

Traditional micromilling leaves burrs and has a high surface roughness in the workpiece, which compromises the microstructural machining quality. Electrophoresis-assisted ultrasonic micromilling machining (EUMM) is proposed to solve this problem. An electrophoresis assisted electric field is applied to attract abrasive particles into the machining gap. Combined with the ultrasonic vibrations of the workpiece, the impact and grinding effect of these abrasive particles in the machining gap removes burrs that are generated during machining and reduces the surface roughness of the microstructure. Micro channels were generated for this study to verify the proposed method. The experimental results show that the EUMM significantly reduces burr formation during microchannel milling. The EUMM also decreases the surface roughness (Ra); the bottom roughness using the EUMM (0.33 µm) is lower than that with either the ultrasonic micromilling (UMM) or traditional micromilling. The EUMM also improves the sidewall roughness since the grinding and particle impacts significantly smooth the sidewalls. The particles during EUMM ensure a low surface roughness of 0.34 µm for the vertical sidewalls. Furthermore, the EUMM has a lesser effect on the width of the micro channels; as the spindle speed increases, the microchannel width only increases from 486 to 498 µm.

Thermomechanical In Situ Monitoring of Bi2Te3 Thin Film and Its Relationship with Microstructure and Thermoelectric Performances

Jeong, Min-Woo,Na, Sekwon,Shin, Haishan,Park, Hong-Bum,Lee, Hoo-Jeong,Joo, Young-Chang 대한금속ᆞ재료학회 2018 ELECTRONIC MATERIALS LETTERS Vol.14 No.4