Ⅲ-Ⅴ족 반도체의 연구 : GaAs의 합성, 단결성 및 특성 Crystal Growth and Characterization of GaAs

이형재,김영기,신영진,박해용,정양준,최춘태,김병호,김진성 全北大學校 基礎科學硏究所 1982 基礎科學 Vol.5 No.1

Temperature of 618 and 1250℃ at As and Ga sities respectively in the horizontal Bridgman furnace and growht speed of 0.7cm/h were found to be optimal for the production of single crystalline GaAs. Self-seeded and unintentionally doped GaAs crystals showd n-type characteristics with Hall mobillity of ∼0.75㎡/V-sec and carrier density of ∼10^19 m^-3 when the mesurements were made right after the growth. About three month later it was found that the same samples were converted to p-type GaAs. The analysis on the p-type sample showed that impurity scattering is dominant at around room temperature and thus the measured Hall mobility was 0.0065㎡/V-sec at 300K. 7.4±0.6 eV was obtained for acoustic deformation potential in the heavy hole band by fitting the theoretical conductivity and Hall coefficient to the corresponding experimental data. The value is very much higher than the theoretically estimated value, 3.6eV. The carrier density variation with temperature obtained from the present analysis gave 0.38 and 0.17 eV respectively for the activation energies of donor and acceptor.

淋菌의 藥劑耐性樣相에 對한 調査硏究

李承薰,石鍾聲,朴蕙瓊,金景俊,柳在根,李龍雨 國立保健硏究院 1973 국립보건연구원보 Vol.10 No.-

혈액투석 환자에서 대퇴신경범증으로 발현된 장골근 및 요근 농양 1예

이준상,강동구,신상열,윤재호,조영일,고성은,유영범,전혜정,진춘조,송종오 대한신장학회 2004 대한신장학회잡지 Vol.23 No.1

스마트폰을 이용한 ID/PW 기반 강화된 사용자 인증 시스템 설계

"채영진", "이진우", "이진해", "조인준" 배재대학교 공학연구소 2015 공학논문집 Vol.17 No.1

현재 사용하고 있는 여러 인증방법은 단순한 ID/PW와 인증서, 지문/홍채 인식, 전화, 보안카드, OTP등 다양한 기술들을 사용하고 있다. 하지만 단순한 ID/PW방식은 보안에 취약한 단점이 있고, 다른 인증 방법들은 취약점을 해결 하였지만 이를 활용하기 위해서는 소요되는 비용과 복잡성이 내재 되어있다. 본 논문에서는 기존의 인증 방법의 보안강도를 유지하면서 우리가 흔히 가지고 있는 스마트폰을 활용하여 저비용으로 사용자 인증을 보다 안전하게 할 수 있는 방안을 제안 하였다. The user authentication method, which is presently used on application system, is in general use of diverse technology. For example, the authentication certificate, fingerprint, IRIS, cell phone, security card, and OTP including simple ID/PW are the current system we use in daily life. However, when people use simple ID/PW, they are able to feel the method of ID/PW is vulnerable to security. To figure out this problem, people invented any other ways to get over this problem. However, it also causes other weak points such as complexity and cost for commercialization. In this paper, it suggests smartphone method. This is more secure than before. In addition, in terms low cost, this can be much effective way. Therefore, it suggests better security strength and economical solution for authentication system .

응급실 급성심근경색증 환자의 체류시간에 영향을 미치는 요인에 관한 연구

정혜경,김해준,윤석준,이준영,이희영 한국의료QA학회 2003 한국의료질향상학회지 Vol.10 No.1

Background : The purpose of this study is to investigate the influencing factors on the length of emergency department stay of patients with acute myocardial infraction. Methods : we reviewed medical records of all patients who were Hospitalized with acute myocardial infraction from March 1, 2002 to February 28, 2003. Results : The average length of stay in the emergency room of the subjects was 182.74 minutes. After the emergency room treatment, 48.1% of the subjects were transferred to intensive care unit. The hospitalization through emergency room mostly took place in the office hours. There were more patients on Monday. The influencing factors on the length of stay in the emergency room of patients with acute myocardial infraction were emergency room arrival time which was classified in seasons, treatment hours of specialized doctors, medical care insurance and required time of radiologic examination. Conclusion : In order to reduce the length of emergency room stay, it might be an available solution secure enough spaces, facility, and staff of the radiologic test only for the patients of the emergency room. And the effective use of emergency facility and space, establishment of standardized treatment guideline, and provision of emergency treatment support system are also needed.

The effects of simultaneous combined exposure to CDMA and WCDMA electromagnetic fields on rat testicular function

Lee, Hae‐,June,Jin, Yeung Bae,Kim, Tae‐,Hong,Pack, Jeong‐,Ki,Kim, Nam,Choi, Hyung‐,Do,Lee, Jae‐,Seon,Lee, Yun‐,Sil Wiley Subscription Services, Inc., A Wiley Company 2012 Bioelectromagnetics Vol.33 No.4

<P><B>Abstract</B></P><P>Wireless mobile phones and other telecommunication devices are used extensively in daily life. We therefore examined the effects of combined exposure to radiofrequency electromagnetic fields (RF‐EMF) on rat testicular function, specifically with respect to sensitive processes such as spermatogenesis. Male rats were exposed to single code division multiple access (CDMA) and wideband code division multiple access (WCDMA) RF signals for 12 weeks. The RF exposure schedule comprised 45 min/day, 5 days/week for a total of 12 weeks. The whole‐body average specific absorption rate (SAR) of CDMA and WCDMA was 2.0 W/kg each or 4.0 W/kg in total. We then investigated the correlates of testicular function such as sperm count in the cauda epididymis, testosterone concentration in the blood serum, malondialdehyde concentrations in the testes and epididymis, frequency of spermatogenesis stages, and appearance of apoptotic cells in the testes. We also immunoblotted for p53, bcl2, GADD45, cyclin G, and HSP70 in the testes of sham‐ and combined RF‐exposed animals. Based on the results, we concluded that simultaneous exposure to CDMA and WCDMA RF‐EMFs at 4.0 W/kg SAR did not have any observable adverse effects on rat spermatogenesis. Bioelectromagnetics 33:356–364, 2012. © 2011 Wiley Periodicals, Inc.</P>

FYN promotes mesenchymal phenotypes of basal type breast cancer cells through STAT5/NOTCH2 signaling node

Lee, Ga-Hang,Yoo, Ki-Chun,An, Yoojeong,Lee, Hae-June,Lee, Minyoung,Uddin, Nizam,Kim, Min-Jung,Kim, In-Gyu,Suh, Yongjoon,Lee, Su-Jae Nature Publishing Group UK 2018 Oncogene Vol.37 No.14

<P>Basal type breast cancer is the most aggressive and has mesenchymal features with a high metastatic ability. However, the signaling node that determines the basal type features in breast cancer remains obscure. Here, we report that FYN among SRC family kinases is required for the maintenance of basal type breast cancer subtype. Importantly, FYN enhanced NOTCH2 activation in basal type breast cancer cells through STAT5-mediated upregulation of Jagged-1 and DLL4 NOTCH ligands, thereby contributed to mesenchymal phenotypes. In addition, we found that high levels of FYN persist in basal type breast cancer cells by a positive feedback loop between FYN and STAT5. FYN interacted directly with STAT5 and increased p-STAT5 that further acts as a transcription factor for FYN. Taken together, our findings demonstrate a pivotal role of FYN and its downstream effectors in maintaining the basal type features in breast cancer.</P>

Combined effects of 60 Hz electromagnetic field exposure with various stress factors on cellular transformation in NIH3T3 cells

Lee, Hae‐,June,Jin, Yeung Bae,Lee, Jae Seon,Choi, Jong‐,Il,Lee, Ju‐,Woon,Myung, Sung Ho,Lee, Yun‐,Sil Wiley Subscription Services, Inc., A Wiley Company 2012 BioElectroMagnetics Vol.33 No.3

<P><B>Abstract</B></P><P>Epidemiological studies have suggested that extremely low‐frequency magnetic fields (ELF‐MF) are associated with an increased incidence of cancer. Studies using in vitro systems have reported mixed results for the effects of ELF‐MF alone, and the World Health Organization (WHO) Research Agenda published in 2007 suggested that high priority research should include an evaluation of the co‐carcinogenic effects of ELF‐MF exposure using in vitro models. Here, the carcinogenic potential of ELF‐MF exposure alone and in combination with various stress factors was investigated in NIH3T3 mouse fibroblasts using an in vitro cellular transformation assay. NIH3T3 cells were exposed to a 60 Hz ELF‐MF (1 mT) alone or in combination with ionizing radiation (IR), hydrogen peroxide (H<SUB>2</SUB>O<SUB>2</SUB>), or c‐Myc overexpression, and the resulting number of anchorage‐independent colonies was counted. A 4 h exposure of NIH3T3 cells to ELF‐MF alone produced no cell transformation. Moreover, ELF exposure did not influence the transformation activity of IR, H<SUB>2</SUB>O<SUB>2</SUB>, or activated c‐Myc in our in vitro assay system, suggesting that 1 mT ELF‐MF did not affect any additive or synergistic transformation activities in combination with stress factors such as IR, H<SUB>2</SUB>O<SUB>2</SUB>, or activated c‐Myc in NIH3T3 cells. Bioelectromagnetics 33:207–214, 2012. © 2011 Wiley Periodicals, Inc.</P>

Aβ pathology downregulates brain mGluR5 density in a mouse model of Alzheimer

Lee, Minkyung,Lee, Hae-June,Park, In Suh,Park, Ji-Ae,Kwon, Yeon Ju,Ryu, Young Hoon,Kim, Chul Hoon,Kang, Joo Hyun,Hyun, In Young,Lee, Kyo Chul,Choi, Jae Yong Pergamon Press 2018 Neuropharmacology Vol.133 No.-

<P><B>Abstract</B></P> <P>The aim of the present study was to evaluate functional changes of mGluR5 expression in advanced Alzheimer's disease (AD) using positron emission tomography (PET) with an mGluR5 specific radiotracer ([<SUP>18</SUP>F]FPEB) in 5xFAD AD model. Subsequently, in the same animal, mGluR5 expression was quantified by immunoassay techniques. The non-displaceable binding potential values for mGluR5 was estimated by the Logan's graphical analysis. Brain PET imaging revealed that radioactivities in the hippocampus and the striatum were significantly lower in 5xFAD mice compared to control animals. Binding values were also significantly lowered in 5xFAD mice. This decline was validated by immunoblotting of protein isolates from brain tissues, as the mean band density for 5xFAD mice had a lower mGluR5 intensity than for wild type mice. These results indicated that mGluR5 levels in 5xFAD mice were down regulated in the limbic system.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Compared with control group, radioactivities in the mGluR5 rich regions such as hippocampus and striatum showed lower uptakes in the 5xFAD group. </LI> <LI> Binding potential values for 5xFAD group also lower than those in the control group. </LI> <LI> These PET findings were validated by immunoblotting. </LI> <LI> Down-regulation of mGluR5 in the AD mice was successfully identified by [<SUP>18</SUP>F]FPEB PET. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Lymphoma development of simultaneously combined exposure to two radiofrequency signals in AKR/J mice

Lee, Hae‐,June,Jin, Yeung Bae,Lee, Jae‐,Seon,Choi, Soo Yong,Kim, Tae‐,Hong,Pack, Jeong‐,Ki,Choi, Hyung Do,Kim, Nam,Lee, Yun‐,Sil Wiley Subscription Services, Inc., A Wiley Company 2011 BioElectroMagnetics Vol.32 No.6

<P><B>Abstract</B></P><P>There are public concerns regarding possible carcinogenic or cancer‐promoting effects of radiofrequency electromagnetic fields (RF‐EMFs) because of the extensive use of wireless mobile phones and other telecommunication devices in daily life. However, so far it is unclear if non‐thermal exposure of single EMF exposure in animal studies has a direct influence on carcinogenesis. Here, carcinogenic effects of combined signal RF‐EMFs on AKR/J mice, which were used for the lymphoma animal model, were investigated. Six‐week‐old AKR/J mice were simultaneously exposed to two types of RF signals: single code division multiple access (CDMA) and wideband code division multiple access (WCDMA). AKR/J mice were exposed to combined RF‐EMFs for 45 min/day, 5 days/week, for a total of 42 weeks. The whole‐body average specific absorption rate (SAR) of CDMA and WCDMA fields was 2.0 W/kg each, 4.0 W/kg in total. When we examined final survival, lymphoma incidence, and splenomegaly incidence, no differences were found between sham‐ and RF‐exposed mice. However, occurrence of metastasis infiltration to the brain in lymphoma‐bearing mice was significantly different in RF‐exposed mice when compared to sham‐exposed mice, even though no consistent correlation (increase or decrease) was observed between male and female mice. However, infiltration occurrence to liver, lung, and spleen was not different between the groups. From the results, we suggested that simultaneous exposure to CDMA and WCDMA RF‐EMFs did not affect lymphoma development in AKR/J mice. Bioelectromagnetics 32:485–492, 2011. © 2011 Wiley‐Liss, Inc.</P>