3D flexible Si based-composite (Si@Si₃N₄)/CNF electrode with enhanced cyclability and high rate capability for lithium-ion batteries

Kim, Si-Jin,Kim, Min-Cheol,Han, Sang-Beom,Lee, Gyu-Ho,Choe, Hui-Seon,Kwak, Da-Hee,Choi, Sun-Yong,Son, Byung-Goo,Shin, Myoung-Sun,Park, Kyung-Won Elsevier 2016 Nano energy Vol.27 No.-

<P><B>Abstract</B></P> <P>Despite extremely high capacity of Si-based anodes in lithium-ion batteries (LIB), Si-based materials have shown a structural collapse caused by a volumetric expansion/contraction during the cycling process. The conventional electrode structure, which consists of active materials, a current collector, a conducting agent, and a binder, actually showed a low loading of active material due to the other heavy components. In this study, we prepared a 3D flexible Si-composite electrode consisting of core (Si)-shell (Si<SUB>3</SUB>N<SUB>4</SUB>) NPs (Si@Si<SUB>3</SUB>N<SUB>4</SUB>) and carbon nanofibers (denoted as Si-composite/CNF). The Si-composite/CNF was directly utilized as an anode in the absence of the other components was electrochemically evaluated using a coin-type cell. The Si-composite/CNF showed a high capacity of 665mAhg<SUP>−1</SUP> at a fairly high current density of 10Ag<SUP>−1</SUP> and an extremely low capacity loss for 2000 cycles.</P> <P><B>Highlights</B></P> <P> <UL> <LI> We prepared Si-composite/CNF exhibits a 3D flexible Si-composite electrode. </LI> <LI> The electrode consists of core (Si)-shell (Si<SUB>3</SUB>N<SUB>4</SUB>) NPs (Si@Si<SUB>3</SUB>N<SUB>4</SUB>) and carbon nanofibers. </LI> <LI> The Si-composite/CNF was directly utilized as an anode. </LI> <LI> Si-composite /CNF exhibited high specific capacity and improved high rate cycling performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Controlled infiltration profile of SiC coating layer on graphite by Si vapor deposition reaction

Kuk-Jin Hwang,Si-Young Bae,Kyoung-Ho Kim,Yoon-Cheol Lee,Jung-Tae Hwang,Heesoo Lee,Seong Min Jeong,Myung-Hyun Lee 한양대학교 세라믹연구소 2019 Journal of Ceramic Processing Research Vol.20 No.2

SiC-coated graphite was successfully fabricated at different temperatures (1300-1600 oC) through a silicon vapor depositionreaction (Si-VDR) process. Si powder was used for the Si source of the SiC coating layers. When Si powder was evaporatedat high temperature near the melting point of bulk Si, Si gases are moved and changed into Si liquid at the surface of thegraphite. The high-temperature process facilitated the formation of SiC coating layers on the graphite. The microstructural,mechanical, and thermal oxidation properties of the coated graphite were investigated.

조혈모세포이식 환자에서 침습성 진균 감염에 대한 Micafungin의 예방 효과 및 안전성

김시현,이동건,최수미,권재철,박선희,최정현,유진홍,이성은,조병식,김유진,이석,김희제,민창기,조석구,김동욱,이종욱,민우성,박종원 대한감염학회 2010 감염과 화학요법 Vol.42 No.3

Background: Micafungin, a potent inhibitor of 1,3-β-D-glucan synthase, is a novel antifungal agent of the echinocandin class. In vitro study showed that micafungin was effective against Aspergillus species as well as Candida species, but clinical data on the prophylactic efficacy against invasive fungal infections (IFIs) other than candidiasis are still lacking. Materials and Methods: We identified 60 consecutive adult hematopoietic stem cell transplantation (HSCT) recipients who received at least 3 doses of micafungin during neutropenic period. Micafungin was started as an alternative in patients who were intolerant or had adverse events (AEs) to primary prophylactic antifungal agents. We retrospectively reviewed the medical records and analyzed the efficacy and safety of micafungin for prophylaxis against IFIs. Results: The patients either had autologous (n=9) or allogeneic (n=51: 1 syngeneic, 24 sibling, 26 unrelated donor) HSCT. Itraconazole oral solution (n=58) was the most frequently used first line antifungal agent for prophylaxis and was administered for median 11 days. The most frequent cause of switch to micafungin was vomiting (n=42). The duration of neutropenia and micafungin administration was median 13 and 12 days, respectively. A successful outcome was achieved in 45 (75%) patients. Empirical antifungal therapy was initiated in 13 (22%) patients. There were 2 cases (3.3%) of breakthrough fungal infections which comprised a probable invasive pulmonary aspergillosis and a possible invasive fungal sinusitis. There was no case of invasive candidiasis. A total of 53 (88%) patients experienced at least one AE regardless of causality during micafungin administration. The most frequent AEs were hypokalemia, vomiting, diarrhea, and elevated serum aspartate aminotransferase or alanine aminotransferase. Among the aforementioned AEs, only 1 case of diarrhea could be classified as a probable relation with micafungin when causality was assessed. There was no AEs that caused discontinuation of micafungin. Conclusions: Micafungin seems to be a safe and effective agent for prophylaxis of IFIs including aspergillosis as well as candidiasis in HSCT recipients. However, further large, prospective, and randomized comparative studies are warranted for aspergillosis.

저농도 노말헥산의 만성폭로가 말초신경계에 미치는 영향

이수진,송재철,장은철,이경영,심상효,박시복,박영재,김현주 大韓産業醫學會 1999 대한직업환경의학회지 Vol.11 No.3

Objectives: The effect of chronic exposure to low levels of n-hexane on peripheral nervous system and the relationship between duration of employment and impairment of peripheral nervous system was studied. Methods : In 21 workers at two shoe-maker factories and 21 unexposed controls, measurement of exposure of solvents, symptom Questionnaire, physical examination and electrophysiological study were conducted. Results : Mean ages of study subjects in the exposed and the unexposed were 39.9 and 40.1 years old. Mean durations of employment were 15.1 and 10.0 years, respectively. Mean concentrations of urinary 2.5-HD were 2.23 mg/g creatinine, 0.23 mg/g creatinine, respectively. Mean concentration of solvents in air were 21.1 ppm of n-hexane, 72.2 ppm of toluene and 0.5 ppm of MEK. There were no differences in the prevalence of subjective symptoms and abnormal neurological signs between the exposed and the unexposed. But vibration extinction time(VAT) of the exposed (8.8 second) was shorter than that of the unexposed (11.9 second) (p<0.05). Mean values of electrophysiological studies(EPS) of the two groups were within normal limit. However, mean conduction velocity of median motor nerve and median F wave(MMNCV and MFCV), mean amplitude of median sensory action potential(MSAP) were decreased in the exposed (p<0.05). Moreover, the rate of abnormal finding more than one in sensory nerves was increased in the exposed than those in the unexposed(p<0.05). Correlation coefficients between duration of employment and mean conduction velocity of median sensory nerve (MSNCV) and between duration of employment and MFCV were -0.57, -0.43, respectively (p<0.05). Conclusions : These results showed that chronic (mean 15 years) low level(mean 23 ppm) exposure to n-hexane cause subclinical impairment of peripheral nervous system. These results also suggest that the longer duration of employment, the shorter values of EPS and VAT.

종횡비가 사각공간내의 혼합대류 열전달에 미치는 영향

이철재,정한식,김시범,권순석 동아대학교 공과대학 부설 한국자원개발연구소 1995 硏究報告 Vol.19 No.2

The effect of aspect ratio on mixed convection heat transfer in a rectangular enclosure has been studied numerically by the finite difference method. This study has been conducted to evaluate the effects of aspect ratio and position of outlet in the mixed convection for various Reynolds numbers at Pr=0.71 and Gr=10000. Independent of outlet position, as Reynolds number increases, the cell decreases at Re≤100 and then increases at Re〉100 in case R=10., but the cell only increases in case of R+0.5 and R=2.0.

개에 있어서 유선 종양의 1례

이시예,정성목,박창식,김명철 충남대학교 형질전환복제돼지연구센터 2007 논문집 Vol. No.10

A 6-years-old 2.5kg female maltese dog with history of multiple mass around mammary gland was referred to Veterinary Medical Teaching Hospital. Chungnam National University. There was no evidence of metastasis in survey radiograph. Cytological finding revealed cell crumps of linear structures of epithelial cell origins. Histopathological finding revealed fibrous stroma. myxomatous lesion. catilagenous metaplasia. hyperplasia of lobular alveoli and ductules. Mass was removed by total mastectomy. After surgery, CBC values showed mild anemia. neutropenia and lymphocytosis. General condition was good. For the appropriate evaluation, more periodical and continuous monitoring is needed.

개에 있어서 유선 종양의 1례

이시예,정성목,박창식,김명철 충남대학교 수의과대학 동물의과학연구소 2004 動物醫科學硏究誌 Vol.12 No.-

A 6-years-old 2.5kg female maltese dog with history of multiple mass around mammary gland was referred to Veterinary Medical Teaching Hospital, Chungnam National University. There was no evidence of metastasis in survey radiograph. Cytological finding revealed cell crumps of linear structures of epithelial cell origins. Histopathological finding revealed fibrous stroma, myxomatous lesion, catilagenous metaplasia, hyperplasia of lobular alveoli and ductules. Mass was removed by total mastectomy. After surgery, CBC values showed mild anemia, neutropenia and lymphocytosis. General condition was good. For the appropriate evaluation, more periodical and continuous monitoring is needed.

저자장 측정을 위한 자기 센서

이철우,김시헌,남태철 경북대학교 센서기술연구소 1995 센서技術學術大會論文集 Vol.6 No.1

This paper describes the highly-sensitive magnetic sensor which can measure the weak magnetic field. Generally, the most important parameters in Hall device which degrade the ability of magnetic detection are the variation of offset according to the variation of temperature and the noises of Hall device and the amplifiers. In this paper, we use a Hall element and compensating circuits to reduce the offset and to make operation of Hall device independent on temperature. The Hall element itself has showed the value of 0.857mV of offset voltage. But we have lowered the offset voltage to 14.34 μV with the compensating circuits. In practice, we have realized the highly-sensitive magnetic sensor for low magnetic field. As a result, the constructed magnetic sensor has showed the magnetic sensitivity of the value of 100 mV/G. The minimum detectable magnetic field of this system with highly-sensitive magnetic sensor is as possible as 0.1 mG.

개에 있어서 자궁축농증의 1례

이시예,김명철,정성목 충남대학교 수의과대학 동물의과학연구소 2004 動物醫科學硏究誌 Vol.12 No.-

A 7-years-old 4.5 kg female maltese dog with history of abdominal distension was referred to Veterinary Teaching Hospital of Chungnam National University. Hematologic showed mild increase in WBC. Mass with soft tissue density was observed near a bladder in abdominal radiography. Ultrasonography revealed enlarged uterus filled with hypoechoeic materials. It was diagnosed as pyometra and ovariohystectomy was performed. After surgery, the dog was recovered.

내시경 수술용 혈관집게 개발에 관한 연구

원시태,이정철 서울産業大學校 2005 논문집 Vol.54 No.1

Traditionally, open surgery requires a lot of time for operation and recovery. The comparision with open surgery and endo surgery is getting popular due to economy, time and cosmetics. This technique can reduce operation and recovery time. Scars due to operation are minimized by using small holes. Popular devices for endo surgery have stick shape, and surgeons are watching the inner space of patient through video scope. For that, the vessel holding is essential process, and endo-clip should hold the vessel tightly and stay in the patient body for very long time. The endo clip applier has the stick shape which can operate the endo clip. In order to improve performance of endo clip and applier, new technique and product was developed in this study, which provides 1) vessel clipping method by using elastic force of clip 2) moving method of clip forwarding and 3) counting method for remaining clip.