• Korea-Australia Rheology Journal
• /
• 제15권2호
• /
• pp.55-61
• /
• 2003

The steady shear flow properties of vaseline generally used as a base of the pharmaceutical dosage forms were studied in the consideration of wall slip phenomenon. The purpose of this study was to show that how slip may affect the experimental steady-state flow curves of semisolid ointment bases and to discuss the ways to eliminate (or minimize) wall slip effect in a rotational rheometer. Using both a strain-controlled ARES rheometer and a stress-controlled AR1000 rheometer, the steady shear flow behavior was investigated with various experimental conditions ; the surface roughness, sample preparation, plate diameter, gap size, shearing time, and loading methods were varied. A stress-controlled rheometer was suitable for investigating the flow behavior of semisolid ointment bases which show severe wall slip effects. In the conditions of parallel plates attached with sand paper, treated sample, smaller diameter fixture, larger gap size, shorter shearing time, and normal force control loading method, the wall slip effects could be minimized. A critical shear stress for the onset of slip was extended to above 10,000 dyne/$\textrm{cm}^2$. The wall slip effects could not be perfectly eliminated by any experimental conditions. However, the slip was delayed to higher value of shear stress by selecting proper fixture properties and experimental conditions.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2009년도 제38회 동계학술대회 초록집
• /
• pp.390-390
• /
• 2010

Superconducting proximity effects of Nb/Si(111) were investigated with scanning tunneling microscopy(STM) and scanning tunneling spectroscopy(STS). A highly-doped($0.002\;{\omega}{\diamondsuit}cm$) Si wafer pieces were used as substrate and Nb source was thermally evaporated onto the atomically clean silicon substrate. The temperature of the silicon sample was held at $600^{\circ}C$ during the niobium deposition. And the sample was annealed at $600^{\circ}C$ for 30 minutes additionally. Volmer-Weber growth mode is preferred in Nb/Si(111) at the sample temperature of $600^{\circ}C$. With proper temperature and annealing time, we can obtain Nb islands of lateral size larger than Nb coherence length(~38nm). And outside of the islands, bare Si($7{\times}7$) reconstructed surface is exposed due to the Volmer-Weber Growth mode. STS measurement at 5.6K showed that Nb island have BCS-like superconducting gap of about 2mV around the Fermi level and the critical temperature is calculated to be as low as 6.1K, which is lower than that of bulk niobium, 9.5K. This reduced value of superconducting energy gap indicates suppression of superconductivity in nanostructures. Moreover, the superconducting state is extended out of the Nb island, over to bare Si surface, due to the superconducting proximity effect. Spatially-resolved scanning tunneling spectroscopy(SR-STS) data taken over the inside and outside of the niobium island shows gradually reduced superconducting gap.

• The Journal of Asian Finance, Economics and Business
• /
• 제8권1호
• /
• pp.723-732
• /
• 2021

On September 25, 2015, 193 countries of the United Nations (UN) General Assembly, signed the 2030 Agenda to work towards attaining 17 Sustainable Development Goals (SDGs) and its associated 169 targets and 232 indicators. With one of the largest renewable energy programs, India is well-poised to be a role model for low-carbon transformation to other Asian countries. However, bridging the financing gap is critical to ensure that the country meets its SDG targets. Though the SDGs identified by the UN are broad-based and interdependent, for ease of analysis we have grouped them into five themes - people, planet, prosperity, peace, and partnership - based on existing UN models. This paper investigates the financing gap for 'green' projects linked to planet-related SDG targets in India. It builds an argument for utilizing green bonds as an instrument to bridge the gap. After establishing the potential of green bonds in raising the finance to meet India's planet-related SDG targets, we look at the current policy landscape and suggest recommendations for successful execution. The paper concludes that deepening of the corporate fixed income securities market and firming up guidelines in line with India's climate action plans are inevitable before green bonds can be considered a viable financing option.

• 대한기계학회논문집B
• /
• 제24권2호
• /
• pp.169-176
• /
• 2000

Natural convection in a wide-gap horizontal annulus is considered, and the transition of flows and the bifurcation phenomenon are investigated for the fluids with Pr=0.2 and 0.3. At Pr=0.2, a bicellular flow pattern is observed at high Rayleigh number, and the solution is unique. At Pr=0.3, both the steady unicellular and bicellular flows exist above a certain critical Rayleigh number. For the fluids of Pr=0.2, the bicellular flow can be obtained by the impulsive heating of the inner cylinder, but it is not obtained from the zero initial condition for Pr=0.3. Hysteresis phenomena have not been observed. A transition from a bicellular flow to a unicellular flow occurs for Pr=0.3.

• Communications for Statistical Applications and Methods
• /
• 제22권1호
• /
• pp.11-14
• /
• 2015

The Great Famine may have had a continued impact on the population structure of North Korea even after the crisis subsided ten years ago. However, there is a significant gap between what has been said about the country and what data indicates. This gap seems inevitable mainly because reliable data are seriously lacking and access is restricted for most scholars outside the country. Yet, it is only reasonable to question why most studies have failed to explain the causality between the Great Famine and accumulated changes in the population of North Korea. In this regard, a recent study conducted by Korean demographers (Jeon et al., 2015) have several implications on the importance of accurate and reliable data when the study involves such rare and scarce information. This paper explores the changing trends of the population structure in North Korea providing a review of recent studies on demographic issues associated with North Korea and offers suggestions on understanding the post-famine effect on the overall changes in the population of North Korea.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2008년도 Techno-Fair 및 합동춘계학술대회 논문집 전기물성,응용부문
• /
• pp.147-148
• /
• 2008

In this paper, we calculated the axial magnetic field at mid-gap plane between upper and lower electrode in vacuum interrupter by means of commercial finite element method Maxwell 3D and compared on the basis of "effective area" criterion. The models used in this paper are coil type(axial magnetic field) vacuum interrupter electrodes which have different numbers of coil segment. We used Dr. Schulmann's experimental equation which indicates minimum critical value of axial magnetic field to diffuse arc.

• 한국경영과학회지
• /
• 제5권1호
• /
• pp.73-88
• /
• 1980

It is hoped that this paper may be a contribution to the solution of further problems arising from the gap between theory and practice. The practical cases in the application of PERT.CPM in Korea was investigated and studied. And the results are presented. These examinations of the actual cases led to a conclusion that in order to apply effectively PERT.CPM and to diminish the gap between the planning and actuality, emphasis must be given to the second factors rather than the first one shown on the network diagram, in the course of the control of the work. These second factors are PERT Status Analysis Report, PERT Emergency and PERT Count Down etc. They are the best methods that can eliminate difficult elements on the critical path, by making the maximum use of slack time.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2000년도 춘계학술대회논문집
• /
• pp.1450-1454
• /
• 2000

In order to understand dynamic characteristics of centrifugal compressor supported foil bearing, of which normal operating speed is about 20,000 ${\sim}$ 50,000 rpm, the rotor whirl is measured using gap sensors. Not only critical speeds of rotor system but also stability of rotor whirl, which are main concerns of the turbo compressor system, are measured using gap sensors by varying the rotating speed the rotor. The stiffness characteristics of bearing system is shown to be almost invariant according to speed variation by the measurement of eccentricity. In addition, from the directional power spectral density function of the measured vibration signal, the isotropy stiffness characteristics of foil bearing system is discussed.

• Communications for Statistical Applications and Methods
• /
• 제25권5호
• /
• pp.545-557
• /
• 2018

The inclusion of covariates in the model often affects not only the estimates of meaningful variables of interest but also its statistical significance. Such gap between statistical and subject-matter significance is a critical issue in huge sample studies. A popular huge sample study, the sample cohort data from Korean National Health Insurance Service, showed such gap of significance in the inference for the effect of obesity on cause of mortality, requiring careful consideration. In this regard, this paper proposes a sample size calibration method based on a Monte Carlo t (or z)-test approach without Monte Carlo simulation, and also proposes a test procedure for subject-matter significance using this calibration method in order to complement the deflated p-value in the huge sample size. Our calibration method shows no subject-matter significance of the obesity paradox regardless of race, sex, and age groups, unlike traditional statistical suggestions based on p-values.

• 정보저장시스템학회:학술대회논문집
• /
• 정보저장시스템학회 2005년도 추계학술대회 논문집
• /
• pp.2-3
• /
• 2005

Air gap control method using a conventional actuator for near field recording technology has been reported. To achieve good performance in the air gap servo and further experiments, the assembling between OL and SIL is the critical procedure. A lens set with NA 1.45 at 405 m has been assembled and tested by using a Twyman-Green interferometer. The tolerance of assembling is very tight and the designing and adjusting procedure must be carefully controlled.