• 융합보안논문지
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• 제23권1호
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• pp.125-137
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• 2023

공공기관을 필두로 민감정보를 취급하는 기업들은 사이버 공격 예방을 위하여 업무망과 인터넷망을 분리 구축하고, 강한 접근통제를 바탕으로 중요 데이터를 보호하고 있다. 그렇기에 업무망과 인터넷망이 연결되는 접점을 수반하는 시스템은 관리적, 기술적으로 안전한 보안환경 구축이 필수적으로 요구되고 있다. 기관에서 사용하고자 하는 모바일 장치의 경우 기기를 통제하기 위한 MDM(Mobile Device Management) 솔루션이 그 예라 할 수 있다. 이 시스템은 모바일 장치 정보, 사용자 정보 등의 민감정보를 인터넷망에서 취급하여 동작하므로 운영 시 각별한 보안대책이 요구된다. 본 연구에서 인터넷망에서 반드시 운영되어야 하는 시스템에서의 민감정보 데이터 처리를 내부망에서 관리할 수 있도록 모델을 제시하였으며, 이를 망연동 솔루션을 기반으로 한 MDM 솔루션을 중심으로 기능 설계 및 구축하였다.

• 한국재료학회지
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• 제20권11호
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• pp.606-610
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• 2010

Films consisting of a silicon quantum dot superlattice were fabricated by alternating deposition of silicon rich silicon nitride and $Si_3N_4$ layers using an rf magnetron co-sputtering system. In order to use the silicon quantum dot super lattice structure for third generation multi junction solar cell applications, it is important to control the dot size. Moreover, silicon quantum dots have to be in a regularly spaced array in the dielectric matrix material for in order to allow for effective carrier transport. In this study, therefore, we fabricated silicon quantum dot superlattice films under various conditions and investigated crystallization behavior of the silicon quantum dot super lattice structure. Fourier transform infrared spectroscopy (FTIR) spectra showed an increased intensity of the $840\;cm^{-1}$ peak with increasing annealing temperature due to the increase in the number of Si-N bonds. A more conspicuous characteristic of this process is the increased intensity of the $1100\;cm^{-1}$ peak. This peak was attributed to annealing induced reordering in the films that led to increased Si-$N_4$ bonding. X-ray photoelectron spectroscopy (XPS) analysis showed that peak position was shifted to higher bonding energy as silicon 2p bonding energy changed. This transition is related to the formation of silicon quantum dots. Transmission electron microscopy (TEM) and electron spin resonance (ESR) analysis also confirmed the formation of silicon quantum dots. This study revealed that post annealing at $1100^{\circ}C$ for at least one hour is necessary to precipitate the silicon quantum dots in the $SiN_x$ matrix.

• 대한한의학회지
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• 제27권1호
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• pp.146-154
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• 2006

Objectives : Siguan points (LI4, LR3) have been most frequently applied for various diseases, especially different digestive disorders such as constipation, abdominal pain or various intestinal inflammatory diseases. The fact that gastrointestina movement is closely connected with physiologic functions or pathologic process of alimentary canal led us to ask the question if Siguan points affects on intestinal motility. Design: To investigate the effect of Siguan acupuncture on the intestinal movement in both physiologic and pathologic conditions, we divided the experimental animals into 12 groups. Six groups were pre-treated with loperamide (0.5 mg/kg, sc) or scoploamine (0.5 mg/kg, sc) to suppress the intestinal movement and another three groups were pretreated with carbachol (0.5 mg/kg, po) to activate it, whereas the rest three groups didn't receive any pretreatment to be kept in the physiological condition. After the administration with charcoal meal, mice were acupunctured bilaterally on sham point or Siguan points as the manner of tap-stimulation, with the exception of no acupuncture groups. Methods : Mice were scarified in twenty minutes after the administration of charcoal to measure the distance of charcoal passage from stomach-duodenal junction. The effect on intestinal movement was presented by calculating the relative distance where charcoal arrived to total length of small intestine. Results : In physiological state, charcoal meal passed around 53%, and there was no significant difference between Siguan points and sham points groups. On the other hand. Siguan points-sitimulation significantly ameliorated loperamide or scoplolamine-induced suppressed travel rate of 17.3 % and 18.6% in sham point into 26% and 26.3% respectively (p<0.05). In carbachol-induced accelerated condition, Siguan points-stimulation didn't affect intestinal motility comparing to sham point group passed about 97.6%. Conclusions : These results postulate that acupuncture at Siguan points have a therapeutic effect by restoring cholinergic activity on pathogenically suppressed intestinal peristalsis, but does not affect the gastrointestinal motility in the normal or accelerated condition.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2018년도 춘계학술대회 논문집
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• pp.102-102
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• 2018

Electronic industry had required the finer size and the higher performance of the device. Therefore, 3-D die stacking technology such as TSV (through silicon via) and micro-bump had been used. Moreover, by the development of the 3-D die stacking technology, 3-D structure such as chip to chip (c2c) and chip to wafer (c2w) had become practicable. These technologies led to the appearance of HBM (high bandwidth memory). HBM was type of the memory, which is composed of several stacked layers of the memory chips. Each memory chips were connected by TSV and micro-bump. Thus, HBM had lower RC delay and higher performance of data processing than the conventional memory. Moreover, due to the development of the IT industry such as, AI (artificial intelligence), IOT (internet of things), and VR (virtual reality), the lower pitch size and the higher density were required to micro-electronics. Particularly, to obtain the fine pitch, some of the method such as copper pillar, nickel diffusion barrier, and tin-silver or tin-silver-copper based bump had been utillized. TCB (thermal compression bonding) and reflow process (thermal aging) were conventional method to bond between tin-silver or tin-silver-copper caps in the temperature range of 200 to 300 degrees. However, because of tin overflow which caused by higher operating temperature than melting point of Tin ($232^{\circ}C$), there would be the danger of bump bridge failure in fine-pitch bonding. Furthermore, regulating the phase of IMC (intermetallic compound) which was located between nickel diffusion barrier and bump, had a lot of problems. For example, an excess of kirkendall void which provides site of brittle fracture occurs at IMC layer after reflow process. The essential solution to reduce the difficulty of bump bonding process is copper to copper direct bonding below $300^{\circ}C$. In this study, in order to improve the problem of bump bonding process, copper to copper direct bonding was performed below $300^{\circ}C$. The driving force of bonding was the self-annealing properties of electrodeposited Cu with high defect density. The self-annealing property originated in high defect density and non-equilibrium grain boundaries at the triple junction. The electrodeposited Cu at high current density and low bath temperature was fabricated by electroplating on copper deposited silicon wafer. The copper-copper bonding experiments was conducted using thermal pressing machine. The condition of investigation such as thermal parameter and pressure parameter were varied to acquire proper bonded specimens. The bonded interface was characterized by SEM (scanning electron microscope) and OM (optical microscope). The density of grain boundary and defects were examined by TEM (transmission electron microscopy).

• Tuberculosis and Respiratory Diseases
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• 제40권3호
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• pp.236-249
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• 1993

연구배경 : 정상 폐상피세포에서는 항상 생성되고 있는 활성산소(oxygen radical)에 의한 유해작용에 노출되어 있고, 이들 유해 산소들은 폐기종과 같은 폐질환의 원인 기전으로 생각되고 있다. 본 연구에서는 이 방법을 이용하여 만든 폐상피세포 단일막에서 전기생리학적인 관점에서 물질의 이동지표인 short-circuit current(Isc)와 조직저항(R)에 대한 활성산소의 하나인 $H_2O_2$(hydrogen peroxide)가 어떤 영향을 미치는지를 연구함으로서 세포생리학적 기전을 구명하고자 한다. 방법 : Tissue culture-treated polycarbonant membrane filter 에서 배양시킨 쥐 제 2 형 폐상피세포 배양 단일막에서 $H_2O_2$의 능동적 이온 이동 (Isc) 과 수동적 용질이동에 대한 조직저항(R)에 미치는 효과를 관찰하였다. 배양 제 3 일과 제 4 일째 단일막을 수정된 Ussing chamber에 설치하고 막 양측에 HEPES-buffered Ringer 용액으로 incubation 하였다. 외부에서 0~100 mM 농도의 $H_2O_2$를 apical 또는 basolateral side에 작용시켜 Isc와 R의 변화를 관찰하였다. 폐상피세포 장벽이 외부의 $H_2O_2$에 대하여 방어작용을 가지는 세포내 catalase 활성도를 측정하고, catalase 억제제인 aminotriazol(ATAZ) 20 mM의 효과도 함께 관찰하였다. 결과 : 이 단일막은 형태학적으로 보아서 in vivo 에서의 포유류 제 1 형 폐상피세포 장벽의 특성을 나타내고 세포들 사이는 tight junction을 이루며(조직저항 R: 2,000 ohm-$cm^2$ 이상) sodium ion의 능동적 이동 (Isc: 5 ${\mu}A/cm^2$)을 보였다. $H_2O_2$는 dose-dependent 양식으로 Isc와 R 모두 감소시켰다. Apical side에 작용하는 $H_2O_2$에 있어서는 60분에 50% 억제하는 농도인 $ED_{50}$는 Isc와 R은 약 4mM 이었으나 basolateral side의 경우는 약 0.04mM 로서 그 작용 강도는 apical에 비하여 약 100배 정도 더 컸다. ATAZ 존재시 apical side의 $ED_{50}$는 0.4mM로 감소하였으나 basolateral side의 경우 변화가 없었다. $H_2O_2$의 제거율은 apical 또는 basolateral side 어느 쪽에 존재하든 같았으며, 세포내 catalase 활성도는세포배양기간이 길어짐에 따라 증가함을 보였다. 결론 : 이상의 실험결과는 basolateral side에 작용하는 $H_2O_2$는 세포내 막구성성분 중 basolateral 측에 존재하는 곳에(예, $Na^+,\;K^+$-APTase) 직접 장애를 미칠 것으로 생각된다. 한편 apical side에 작용하는 $H_2O_2$는 막성분에 도달하기 전에 세포내에 존재하는 catalase에 의하여 대부분 그 작용을 잃게 된다. 결론적으로 Isc와 R로 측정된 폐상피세포 장벽의 특성은 $H_2O_2$에 의하여 손상을 받고 apical side 보다는 basolateral side 측정이 더 손상을 잘 받게 된다.