• 한국항해항만학회지
• /
• 제34권3호
• /
• pp.205-211
• /
• 2010

밸러스트수 처리를 위한 Plasma Gun의 전기적 특성과 오존 생성에 미치는 주요 운전변수들의 영향에 관해 실험실 규모 연구를 수행하였다. 방전개시전압보다 높은 전압이 인가되면 방전이 시작되고 오존이 생성되었으며 전압이 증가함에 따라 기체로 전달되는 에너지 및 오존 농도가 거의 선형적으로 증가하였다. 오존 생성 측면에서 최적의 에너지 효율성을 얻을 수 있는 전극간 거리가 존재하였으며 실험된 장치에서는 1.95 mm의 전극간 거리에서 최적 효율이 얻어졌다. 전기에너지 특성에 미치는 내부전극 재질의 영향은 무시할만한 수준이었으나 내부전극의 전기전도도와 열전도도 차이가 오존 생성에 큰 영향을 미치는 것으로 나타났다. 일정한 Plasma Gun 구조에서 오존 생성은 기체로 전달되는 에너지밀도에 의해 중요한 영향을 받는 것으로 나타났으며 유입되는 기체의 산소함량이 증가할수록 오존 생성이 증가하는 것으로 나타났다.

• 한국한의학연구원논문집
• /
• 제7권1호
• /
• pp.39-54
• /
• 2001

This is a study on the methods of taking prescriptions in SANGHANRON (傷寒論), and after this, numbers of results have been obtained. SANGHANRON was written by Chang-Ki (張機) in the 2nd century, so it reflexes the usage of prescriptions of previous age indirectly. And gave affects on the methods of taking prescriptions to the oriental medicine doctors of next generation. Before Han-Dynasty (漢代), there were not so many publications connected with Oriental Medicine. Besides, some books couldn't hand down to next generation due to the gap of time and space. As time goes by, letters in medical books changed little by little, so contents connected with taking decoctions changed too. The effects of decoction and herb tea can be changed by the flexibility of methods of taking medicines, so we have to decide what kinds of taking methods should be taken and adapted to patients by the most effective way. There are many kind of methods of taking decocted prescriptions in SANGHANRON, so Chang-Ki selected the most appropriate method considering degree and position of disease and condition of patient. But nowadays, due to inconvenient procedure of taking medicines, some methos are not in common in clinical medicin. So this study was started to look back upon the changes of taking prescriptions and gave effort to find out the propriety of variation of taking prescriptions. In SANGHANRON, many kinds of taking prescriptions appeared from once a day to six times a day, except these, some prescriptions have to be taken little by little. These methods of taking prescriptions simplified as time pass by, but this change may give influence to the effect of medicine and finally we can't gain expected therapeutic value. So we have to distinguish the methods -though complicated and troublesome- in clinical medicine to make perfection more perfect in treating patients, and further studies have to be followed to prove the propriety of these methods.

• Steel and Composite Structures
• /
• 제27권6호
• /
• pp.727-745
• /
• 2018

The design criteria and the corresponding performance levels characterize the response of extended stiffened end-plate beam-to-column joints. In order to guarantee a ductile behavior, hierarchy criteria should be adopted to enforce the plastic deformations in the ductile components of the joint. However, the effectiveness of thesecriteria can be impaired if the actual resistance of the end-plate material largely differs from the design value due to the potential activation of brittle failure modes of the bolt rows (e.g., occurrence of failure mode 3 in the place of mode 1 per bolt row). Also the number and the position of bolt rows directly affect the joint response. The presence of a bolt row in the center of the connection does not improve the strength of the joint under both gravity, wind and seismic loading, but it can modify the damage pattern of ductile connections, reducing the gap opening between the end-plate and the column face. On the other hand, the presence of a central bolt row can influence the capacity of the joint to resist the catenary actions developing under a column loss scenario, thus improving the joint robustness. Aiming at investigating the influence of these features on both the cyclic behavior and the response under column loss, a wide range of finite element analyses (FEAs) were performed and the main results are described and discussed in this paper.

• Investigative Magnetic Resonance Imaging
• /
• 제20권2호
• /
• pp.88-94
• /
• 2016

Purpose: Fluid-attenuated inversion recovery (FLAIR) imaging can be obtained faster with shorter repletion time (TR), but it gets noisier. We hypothesized that shorter-TR FLAIR obtained at 3 tesla (3T) with a 32-channel coil may be comparable to conventional FLAIR. The aim of this study was to compare the diagnostic value between conventional FLAIR (TR = 9000 ms, FLAIR9000) and shorter-TR FLAIR (TR = 6000 ms, FLAIR6000) at 3T in terms of diffusion-weighted imaging-FLAIR mismatch. Materials and Methods: We recruited 184 patients with acute ischemic stroke (28 patients < 4.5 hours) who had undergone 5-mm diffusion-weighted imaging (DWI) and two successive 5-mm FLAIR images (no gap; in-plane resolution, $0.9{\times}0.9mm$) at 3T with a 32-channel coil. The acquisition times for FLAIR9000 and FLAIR6000 were 108 seconds (generalized autocalibrating partially parallel acquisitions [GRAPPA] = 2) and 60 seconds (GRAPPA = 3), respectively. Two radiologists independently assessed the paired imaging sets (DWI-FLAIR9000 and DWI-FLAIR6000) for the presence of matched hyperintense lesions on each FLAIR imaging. The signal intensity ratios (area of DWI lesion to contralateral normal-appearing region) on both FLAIR imaging sets were compared. Results: DWI-FLAIR9000 mismatch was present in 39 of 184 (21.2%) patients, which was perfectly the same on FLAIR6000. Three of 145 patients (2%) with DWI-matched lesions on FLAIR9000 had discrepancy on FLAIR6000, showing no significant difference (P > 0.05). Interobserver agreement was excellent for both DWI-FLAIR9000 and DWI-FLAIR6000 (k = 0.904 and 0.883, respectively). Between the two FLAIR imaging sets, there was no significant difference of signal intensity ratio (mean, standard deviation; $1.25{\pm}0.20$; $1.24{\pm}0.20$, respectively) (P > 0.05). Conclusion: For the determination of mismatch or match between DWI and FLAIR imaging, there is no significant difference between FLAIR9000 and FLAIR6000 at 3T with a 32-channel coil.

• 통상정보연구
• /
• 제16권2호
• /
• pp.279-296
• /
• 2014

본 연구는 우리나라 중소기업의 기술수출에 초점을 맞추어 이에 대한 폭넓은 고찰과 함께, 2003년-2011년까지 72개국과의 기술무역 data를 활용하여 우리나라 중소기업의 기술수출에 영향을 미치는 다양한 변수를 발굴, 이에 대한 실증분석을 시도하였다. 이러한 실증분석을 통해 우리나라 중소기업의 기술수출에 영향을 미치는 다양한 요인과의 인과관계 분석이 본 연구의 목적이다. 실증결과, 일인당 GDP가 높고, GDP 대비 R&D지출이 많은 국가일수록, 우리나라 대기업의 기술도입이 적은 국가일수록, 또한 기술무역 상대국의 미국특허 등록 기업수가 적은 국가일수록 우리나라 중소기업의 기술수출은 증가하는 것으로 추정되고 있다. 따라서 우리나라 중소기업들이 기술수출 대상국을 선정함에 있어 유의미하게 도출된 요인들을 활용, 기술수출 경쟁력 제고시 고려되어야 함을 시사하고 있다.

• 정보교육학회논문지
• /
• 제10권3호
• /
• pp.299-306
• /
• 2006

교육인적자원부는 ICT 활용 교육을 주도해 나가는데 가장 중심이 되는 교사의 ICT 활용 능력을 신장시키기 위해 다양한 방안들을 수립하여 추진하고 있다. 그러나 현재 시행되고 있는 교사의 ICT 활용능력 신장에 관한 대부분의 노력들은 ICT를 직무활동에 효과적으로 활용할 수 있는 능력보다는 기술소양 능력에 중점을 두고 있다. 그러므로 본 논문에서는 교사의 직무활동을 분석하고, 국내외 교사 ICT 활용능력 평가도구를 비교 분석하여 교사의 ICT활용능력 자기평가 도구를 개발하였다. 또한, 개발된 웹 기반 교사의 ICT 활용능력 자기평가도구를 광주와 전남 지역의 교사를 대상으로 적용하여 성별, 직위별, 지역별, 교육경력별 ICT 활용능력 수준 등을 조사분석하였다.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제40권
• /
• pp.8.1-8.6
• /
• 2018

Background: This study was to evaluate the effect of bone graft procedure on the primary stability of implants installed in fresh sockets and assess the vertical alteration of peri-implant bone radiographically. Methods: Twenty-three implants were inserted in 18 patients immediately after tooth extraction. The horizontal gap between the implant and bony walls of the extraction socket was grafted with xenografts. The implant stability before and after graft procedure was measured by Osstell Mentor as implant stability quotient before bone graft (ISQ bbg) and implant stability quotient after bone graft (ISQ abg). Peri-apical radiographs were taken to measure peri-implant bone change immediately after implant surgery and 12 months after implant placement. Data were analyzed by independent t test; the relationships between stability parameters (insertion torque value (ITV), ISQ abg, and ISQ bbg) and peri-implant bone changes were analyzed according to Pearson correlation coefficients. Results: The increase of ISQ in low primary stability group (LPSG) was 6.87 ± 3.62, which was significantly higher than the increase in high primary stability group (HPSG). A significant correlation between ITV and ISQ bbg (R = 0.606, P = 0.002) was found; however, age and peri-implant bone change were not found significantly related to implant stability parameters. It was presented that there were no significant peri-implant bone changes at 1 year after bone graft surgery. Conclusions: Bone graft procedure is beneficial for increasing the primary stability of immediately placed implants, especially when the ISQ of implants is below 65 and that bone grafts have some effects on peri-implant bone maintenance.

• Bulletin of the Korean Chemical Society
• /
• 제33권6호
• /
• pp.1861-1866
• /
• 2012

The new semiconducting copolymers with 4,4-dialkyl-$4H$-cyclopenta[2,1-$b$:3,4-$b^{\prime}$]dithiophene and 2,2-dimethyl-$2H$-benzimidazole units were synthesized. The fused aromatic rings, such as cyclopentadithiophene (CPDT) unit, can make the polymer backbone more rigid and coplanar, which induces long conjugation length, narrow band gap, and strong intermolecular ${\pi}-{\pi}$ interaction. The stacking ability was controlled through attaching of linear or branched alkyl side chains. The spectra of PEHCPDTMBI and PHCPDTMBI in the solid films show absorption bands with maximum peaks at 401, 759 and 407, 768 nm, and the absorption onsets at 925 and 954 nm, corresponding to band gaps of 1.34 and 1.30 eV, respectively. The devices comprising PHCPDTMBI with $TiO_X$ showed a $V_{OC}$ of 0.39 V, a $J_{SC}$ of 1.14 $mA/cm^2$, and a $FF$ of 0.34, giving a power conversion efficiency of 0.15%. The PHCPDTMBI with linear alkyl chain on CPDT shows good solubility in organic solvent with higher PCE value than that of PEHCPDTMBI.

• 대한화학회지
• /
• 제37권6호
• /
• pp.549-554
• /
• 1993

티타늄 금속판을 공기산화와 수증기 산화하여 만든 Ti$O_{2-x}$ 박막을 시료로 사용하여 1M NaOH 용액에서 광전기화학적 성질을 연구하였다. 높은 온도에서 제조된 Ti$O_{2-x}$ 전극들은 낮은 온도에서 제조된 전극들보다 더 음의 값으로 주어지는 flat band potential($V_{fb}$)과 더 높은 donor density($N_D$)를 가졌다. 전극전위의 변화에 따른 광전류 측정과 Mott-Schottky plot로부터 얻은 $V_{fb}$는 -0.95 ∼ -1.1 V 사이에서 비슷한 값으로 주어졌다. 자외부 영역의 광을 완전히 차단하는 TiO2 단결정을 필터로 하여 가시부 영역의 광전류를 측정할 때 분해능이 좋은 slit를 사용한 경우 좋은 sub band gap 광반응을 볼 수 있었다.

• 한국재료학회:학술대회논문집
• /
• 한국재료학회 2009년도 춘계학술발표대회
• /
• pp.16.1-16.1
• /
• 2009

We have fabricated solution processed oxide semiconductor active layer for thin film transistors (TFTs). The oxide semiconductor layers were prepared by ink-jet printing the sol-gel precursor solution based on doped-ZnO. Inorganic ZnO-based thin films have drawn significant attention as an active channel layer for TFTs applications alternative to conventional Si-based materials and organic semiconducting materials, due to their wide energy band gap, optical transparency, high mobility, and better stability. However, in spite of such excellent device performances, the fabrication methods of ZnO related oxide active layer involve high cost vacuum processes such as sputtering and pulsed laser deposition. Herein we introduced the ink-jet printing technology to prepare the active layers of oxide semiconductor. Stable sol-gel precursor solutions were obtained by controlling the composition of precursor as well as solvents and stabilizers, and their influences on electrical performance of the transistors were demonstrated by measuring electrical parameters such as off-current, on-current, mobility, and threshold voltage. Microstructure and thermal behavior of the doped ZnO films were investigated by SEM, XRD, and TG/DTA. Furthermore, we studied the influence of the ink-jet printing conditions such as substrate temperature and surface treatment on the microstructure of the ink-jet printed active layers and electrical performance. The mobility value of the device with optimized condition was about 0.1-1.0 $cm^2/Vs$ and the on/off current ratio was about $10^6$. Our investigations demonstrate the feasibility of the ink-jet printed oxide TFTs toward successful application to cost-effective and mass-producible displays.