Effects of impact conditions on the electrical and mechanical properties of supersonic cold sprayed Cu–Ni electrodes

Lee, Jong-Gun,Lee, Jong-Hyuk,An, Seongpil,Yoon, Joshua Yeosong,Choi, Jae-Wook,Kang, Min Gu,Lee, Jeong In,Song, Hee-eun,Al-Deyab, Salem S.,James, Scott C.,Kang, Yoonmook,Kim, Donghwan,Yoon, Sam S.,Lee, Elsevier 2017 JOURNAL OF ALLOYS AND COMPOUNDS Vol.695 No.-

<P><B>Abstract</B></P> <P>Supersonic cold sprayed Cu and Ni particles were deposited on Si wafers for potential use as solar-cell front electrodes. Line-printed Ni–Cu electrodes were successfully fabricated with thicknesses between 30 and 50 μm. Choice of carrier gas (nitrogen and air) and effects of particle size and impact velocity on the electrical and mechanical properties of these Ni–Cu electrodes were quantified. The carrier gas had no discernable effect on electrode properties while increased particle sizes slightly decreased electrode specific resistivities. Impact velocity had the most pronounced influence on electrode electrical properties. Both the contact and specific resistivities decreased nearly linearly with increasing impact velocity. Adhesion strength was measured with a STAB-TEST instrument and found sufficient for all measured electrodes. The electrodes were further characterized using scanning electron microscopy, energy-dispersive X-ray spectroscopy, and auger electron spectroscopy.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Supersonically sprayed Cu and Ni particles were deposited on Si wafers for potential use as solar-cell front electrodes. </LI> <LI> Line-printed Ni–Cu electrodes were successfully fabricated with thicknesses between 30 and 50 μm. </LI> <LI> Effects of impact conditions on the electrical and mechanical properties of these Ni–Cu electrodes were quantified. </LI> <LI> Both the contact and specific resistivities decreased nearly linearly with increasing impact velocity. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Design and Development of a Cylinder Type Electrospinning Device for the Mass Production of Nanofibers

Lee, Jung Ho,Lee, Joshua,Unnithan, Afeesh Rajan,Kim, Cheol Sang,Park, Chan Hee American Scientific Publishers 2017 Journal of Nanoscience and Nanotechnology Vol.17 No.6

<P>Electrospinning is a simple, scalable and versatile technique, using strong electrical fields to draw polymer solutions to produce fibers with diameters ranging from micrometers to nanometers that exhibit a high surface area to volume ratio. Electrospun fibers have been the focus of research for applications such a d biomedical, water treatment filter and next-generation energy storage device etc. However, the mass production of electrospun nanofibers is not yet completely established and hence it has to struggle in terms of production cost reduction. Keeping it in mind, in this study we developed a high speed nanofiber production system composed of one meter width cylinder type nozzle block for the mass production of nanofibers. Scanning Electron microscopy (SEM) images and time measurement results showed that our cylinder type mass production system is approximately 80 times more productive than the conventional single nozzle type system. So our system will be able to produce the nanofibers in mass scale and can be effectively applied to various industries, those are in need of large amount of nanofibers.</P>

Best Core Stabilization for Anticipatory Postural Adjustment and Falls in Hemiparetic Stroke

Lee, Nam G.,You, Joshua (Sung) H.,Yi, Chung H.,Jeon, Hye S.,Choi, Bong S.,Lee, Dong R.,Park, Jae M.,Lee, Tae H.,Ryu, In T.,Yoon, Hyun S. Elsevier 2018 Archives of Physical Medicine and Rehabilitation Vol.99 No.11

<P><B>Abstract</B></P> <P><B>Objectives</B></P> <P>To compare the effects of conventional core stabilization and dynamic neuromuscular stabilization (DNS) on anticipatory postural adjustment (APA) time, balance performance, and fear of falls in chronic hemiparetic stroke.</P> <P><B>Design</B></P> <P>Two-group randomized controlled trial with pretest-posttest design.</P> <P><B>Setting</B></P> <P>Hospital rehabilitation center.</P> <P><B>Participants</B></P> <P>Adults with chronic hemiparetic stroke (N=28).</P> <P><B>Interventions</B></P> <P>Participants were randomly divided into either conventional core stabilization (n=14) or DNS (n=14) groups. Both groups received a total of 20 sessions of conventional core stabilization or DNS training for 30 minutes per session 5 times a week during the 4-week period.</P> <P><B>Main Outcome Measures</B></P> <P>Electromyography was used to measure the APA time for bilateral external oblique (EO), transverse abdominis (TrA)/internal oblique (IO), and erector spinae (ES) activation during rapid shoulder flexion. Trunk Impairment Scale (TIS), Berg Balance Scale (BBS), and Falls Efficacy Scale (FES) were used to measure trunk movement control, balance performance, and fear of falling.</P> <P><B>Results</B></P> <P>Baseline APA times were delayed and fear of falling was moderately high in both the conventional core stabilization and DNS groups. After the interventions, the APA times for EO, TrA/IO, and ES were shorter in the DNS group than in the conventional core stabilization group (<I>P</I><.008). The BBS and TIS scores (<I>P</I><.008) and the FES score (<I>P</I><.003) were improved compared with baseline in both groups, but FES remained stable through the 2-year follow-up period only in the DNS group (<I>P</I><.003).</P> <P><B>Conclusions</B></P> <P>This is the first clinical evidence highlighting the importance of core stabilization exercises for improving APA control, balance, and fear of falls in individuals with hemiparetic stroke.</P>

A Dual-Band Power Amplifier Module for GSM/WCDMA Application using LTCC Technology

Joshua Yoo,Joong-Geun Lee,Yong-Gil Shin,Dongsu Kim,Myong-Jae Yoo,Seong-Dae Park,Woo-Sung Lee 대한전자공학회 2005 ITC-CSCC :International Technical Conference on Ci Vol.2005 No.3

A Front End Implementation for GSM/DCS Application using LTCC(Low Temperature Cofired Ceramic) Technology

Joshua Yoo,Joong-Geun Lee,Dongsu Kim,Myoung-Jae Yoo,Sung-Dae Park,Woo-Sung Lee 대한전자공학회 2005 ITC-CSCC :International Technical Conference on Ci Vol.2005 No.1

Remnants of Manshūkoku (Manchukuo): Imamura Eiji, Korean Identity under Japanese Imperialism, and Postcolonial Asian Studies

Joshua Lee Solomon 고려대학교 한국사연구소 2022 International Journal of Korean History Vol.27 No.1

This paper takes Imamura Eiji (1911–?) as a case study in developing a theory of minor literary style and pedagogical poetics in Japanese language Manshū literature. At the same time, it grapples with reading Japanese-language Manshū literature with postcolonial reflexivity. Imamura Eiji was an ethnic Korean who was an active participant in the Japanese language literary community of Japan-occupied Manchuria. While he is best known for his short story “Travel Companions,” this paper contends that his work and position within the Manchukuoan state can be better understood through the juxtaposition of multiple of his diverse works, including another short story entitled “New Womb.” Borrowing from Elleke Boehmer’s “postcolonial poetics,” I approach these texts from the perspective of not merely what politics they attempt, but also how they do so aesthetically and technologically. I conclude that Imamura produced a form of minor style observable in other contemporary literary production as well. While previous work on Imamura has laser focused on decoding his ethnic politics, I argue that we must aim for a more careful and critical reading by remaining aware of the contemporary politics of the academic field and relationality between scholar and text.

Guest Editor’s Introduction: Japanese Imperialism, Modernity, and Korean History

Joshua Lee Solomon 고려대학교 한국사연구소 2022 International Journal of Korean History Vol.27 No.1

Chromosomal Localization of the Human MIG Chemokine Gene to 4q21.21

Lee, Hwang-Ho,Doh, Byung-Ryong,Farber, Joshua M. 大韓免疫學會 1996 大韓免疫學會誌 Vol.18 No.2

Chemokine은 백혈구에 chemoattractant로서 작용을 하는 것으로 알려진 분자량이 비교적 작은 proinflammatory peptide이다. Interferon-γ로 자극된 대식세포로부터 분비되는 MIG는 chemokine중 peptide 특성상 첫번째와 두번째 cystein 사이에 하나의 아미노산이 있는 CXC subfamily의 한 구성원으로 활성화된 T세포에 그 작용을 나타낸다. 저자들은 MIG 유전자를 가지는 하나의 P1 clone을 확보하고 이로부터 MIG cDNA와 hybridization되는 DNA분절을 probe로, 그리고 이 P1 clone이 PCR과 Southern hybridization으로 INP10 유전자를 가지고 있음을 확인하였기에 INP10 cDNA와 hybridization 되는 DNA분절의 일부를 대조 probe로 이용하여 fluorescence in situ hybridization으로 이 두 유전자의 염색체내 자리를 정하였다. 그 결과 MIG의 유전자좌는 4q21.21이었고, 본 실험에 이용된 P1 clone에 대해서 저자들이 확보한 정보로부터 예측할 수 있듯이 INP10의 유전자좌 또한 MIG의 그것과 동일하였다. 이러한 결과는 MIG 유전자의 염색체내 위치를 처음으로 정 한 것은 물론 CXC chemokine은 그들의 아미노산 및 핵산의 상동성 정도에 비례하여 염색체내에 서로 가까이 있고, MIG와 INP10 유전자에 의해서 형성된 소유전자군(mini-cluster)은 다른 CXC chemokine 유전자군(4q12-ql3)보다 염색체의 중심체로부터 말단쪽에 있음을 의미한다.

Novel design and sensitivity analysis of displacement measurement system utilizing knife edge diffraction for nanopositioning stages.

Lee, ChaBum,Lee, Sun-Kyu,Tarbutton, Joshua A American Institute of Physics 2014 Review of scientific instruments Vol.85 No.9

<P>This paper presents a novel design and sensitivity analysis of a knife edge-based optical displacement sensor that can be embedded with nanopositioning stages. The measurement system consists of a laser, two knife edge locations, two photodetectors, and axillary optics components in a simple configuration. The knife edge is installed on the stage parallel to its moving direction and two separated laser beams are incident on knife edges. While the stage is in motion, the direct transverse and diffracted light at each knife edge is superposed producing interference at the detector. The interference is measured with two photodetectors in a differential amplification configuration. The performance of the proposed sensor was mathematically modeled, and the effect of the optical and mechanical parameters, wavelength, beam diameter, distances from laser to knife edge to photodetector, and knife edge topography, on sensor outputs was investigated to obtain a novel analytical method to predict linearity and sensitivity. From the model, all parameters except for the beam diameter have a significant influence on measurement range and sensitivity of the proposed sensing system. To validate the model, two types of knife edges with different edge topography were used for the experiment. By utilizing a shorter wavelength, smaller sensor distance and higher edge quality increased measurement sensitivity can be obtained. The model was experimentally validated and the results showed a good agreement with the theoretically estimated results. This sensor is expected to be easily implemented into nanopositioning stage applications at a low cost and mathematical model introduced here can be used for design and performance estimation of the knife edge-based sensor as a tool.</P>

Human MIG and INP10 Genes form a "Mini-cluster" Distant from a Cluster of Related CXC Chemokine Genes on Chromosome 4

Lee, Hwang-Ho,Doh, Byung-Ryong,Farber, Joshua M. 大韓免疫學會 1996 大韓免疫學會誌 Vol.18 No.2

MIG는 interferon-y로 유도분비되며 시험관내에서 활성화된 T세포의 chemoattraction을 일으키는 chemokine의 하나로 그 유전자좌는 사람 염색체 4q21.21이다. 저자들은 MlG cDNA로부터 고안된 primer set를 이용하여 P1 clone을 얻었는데 이 clone은 CXC chemokine의 하나로 유전자좌가 4q21인 INP10유전자도 포함하고 있었다. 본 연구에서 저자들은 pulsed-field gel electrophoresis를 이용하여 MlG및 INP10유전자는 서로 인접하여 있고 이 "mini-cluster"는 유전자좌가 4q12-13로 알려진 관련된 다른 CXC chemokine 유전자군과는 떨어져 있음을 확인하였다. 본 실험에 이용된 Pl-593 clone의 MIG 와 INP10 유전자 부위의 BamHI 유전자지도를 만들어 INP10 유전자의 3쪽이 MIG 유전자의 5쪽과 가까이 있고 translation 개시부호(start codon;ATG)는 서로 16kb 이내에 있음을 알았다. MlG와 INP10 유전자가 물리적으로 아주 가까이 있음을 밝힌 본 실험결과는 CXC chemokine의 아미노산 서열을 비교분석한 결과와 생물학적으로 이 두 chemokine이 다른 CXC chemokine보다 더 가깝다는 지금까지의 연구결과들을 후원하는 것이다. 제4번 염색체의 MIG/INP10 유전자좌 부위에 interferon으로 유도되는 혹은 T세포를 표적세포로 하는 아직 발견되지 않은 chemokine을 찾아낼 수 있을지 관심이 간다.