• Biomedical Science Letters
• /
• v.13 no.4
• /
• pp.361-368
• /
• 2007

Biological samples can be fixed either by chemical method by using chemical solution or physical methods by using heat treatment. The problem in traditional heat fixation is unsatisfactory quality due to uneven heat conduction in specimen and loss of inner cell contents. Chemical fixation method also bears several intrinsic problems like the limit in specimen size, time consumption in fixative impregnation, and loss of low molecular weight cell components. These factors deteriorate the quality of fixed specimen, thus limit the magnification and contrast of tissue pictures. Microwave heat has been reported to be a good alternative to current chemical methods to overcome these problem. In this study, we tried to introduce the microwave energy method to routine fixation work in hospital. We replaced chemical fixative with saline to provide moderate reaction condition, and used frozen section to reduce time for sample preparation. Temperature was measured at each experiment. The fixation of rat kidney tissue with 2.45 GHz electromagnetic wave and saline showed similar result to the control group fixed with traditional chemical method. Human tumor tissue fixed with 2.45 GHz electromagnetic in frozen section was improved in terms of histochemistry of PAS and immunohistochemistry of tumor marker like cytokeratin. Total turnaround time was reduced from $24\sim38$ h to to $2\sim4$ h. In conclusion, the quality of samples prepared by microwave heating method was at least as good as that of traditional method. If the condition for the fixation of different specimens is standardized, this new method could be applied to routine work in hospital, and could save working time as well.

• Korean Journal of Materials Research
• /
• v.9 no.8
• /
• pp.810-816
• /
• 1999

The variations of crystalline structures and physical proerties of serpentine and talc mineral which was treated in a planetary ball mill, wre investigated by means of X-ray diffraction, FT-IR, DSC-TG, particle size analysis and SEM observation. The crystalline peaks of serpentine and talc in the XRD patterns were gradually reduced with the increase of grinding time and after 120 minutes turned into the amorphous phase, which is attributed to the disordering of the local structure around magnesium. The endothermic peaks for the ground serpentine and talc sample are observed at a considerably lower temperatures than that for the starting sample. A morphological change from the originally flat and irregular shape to spherically agglomerated particles was clearly observed.

• Geomechanics and Engineering
• /
• v.17 no.5
• /
• pp.439-444
• /
• 2019

It is generally known that high strength soil is indicative of well-graded particle size distribution. However, there are some special cases of firm ground despite poor grade distribution, especially a specific gap-graded soil. Based on these discoveries, this study investigated the development of an additive of gap-graded soils designed to increase soil strength. This theoretical concept was used to calculate the mixed ratio required for optimal soil strength of the ground sample. The gap-graded aggregate was added according to Plato's polyhedral theory and subsequently calculated ratio and soil strength characteristics were then compared to characteristics of the original soil sample through various test results. In addition, the underground stress transfer rate was measured according to the test conditions. The test results showed that the ground settlement and stress limit thickness were reduced with the incorporation of gap-graded soil. Further field tests would confirm the reproducibility and reliability of the technology by using gap-graded soil to reinforce soft ground of a new construction site. Gap-graded soil has the potential to reduce the construction cost and time of construction compared to other reinforcing methods.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.7 no.4
• /
• pp.625-634
• /
• 2006

In this paper, an efficient and fast algorithm to reduce calculation amount of FIR(Finite Impulse Responses) filtering is proposed. Proposed algorithm enables arbitrary size of parallel processing, and their structures are also easily derived. Furthermore, it is shown that the number of multiplication/sample is remarkably reduced. For theoretical improvement, numbers of sub filters are compared with those of conventional algorithm. In addition to the theoretical improvement, it is shown that number of element for hardwired implementation are reduced comparison to those of the conventional algorithm.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.2 no.3
• /
• pp.243-255
• /
• 1990

The objective of this study is to present an efficient measurement method of the effective thermal diffusivity for the fibrous insulation material. The non-linear parameter estimation (NPE) method is adapted for this analysis because of its accuracy and its results are compared with those by other direct methods such as CTP, CHP and STD method. A experimental system is constructed with bell-jar vaccum chamber, diffusion pump, tube type furnace, control unit and data acquisition system included with A/D converter and IBM XT/AT personal computer. The typical results obtained from this study are as follows; 1) NPE method can be recommended as an useful and accurate method to measure the effective thermal diffusivity of insuation material because it is shown that the measurement error compared with those by other direct methods is reduced for standard material, NBS-1450b. 2) NPE method can minimize the effects of ill-measured temperature due to external disturbance, because the final value is found by point to point estimating. 3) NPE method dose not depend on the kinds of heat flux, since the surfac temperature are used to estimate the thermal diffusivity. 4) With NPE method, compared with the steady state method, a measuring time and a sample size could be reduced.

• Electrical & Electronic Materials
• /
• v.9 no.6
• /
• pp.605-615
• /
• 1996

In this paper, the effect of alkaline oxide addition such as Li$_{2}$O and Na$_{2}$O on the microstructure and humidity sensitivity of V$_{2}$O$_{5}$(2 mol%)-doped TiO$_{2}$(98 mol%) was investigated as a function of amount (0, 1, 2, 5, 10 mol%) of Li$_{2}$O and Na$_{2}$O additives. The pores in the alkaline free sample were distributed mostly in the range between 0.16 and 1.0.mu.m in diameter and its porosity was 23.29%. Li$_{2}$O caused grain overgrowth and reduced the porosity with a narrow distribution of the pore size, leading to poor humidity sensitivity. Na$_{2}$O helped to enlarge the distribution of the pore size through the formation of small soluble phases. The pore sizes of the sample containing Na$_{2}$O 2mol% were distributed mostly in the range between 1.0 and 2.5.mu.m in diameter and its porosity and intrusion volume of mercury were 31.13 % and 0.1155 mL/g respectively, which consequently improved the humidity sensing characteristics such as the sensitivity and temperature-stability. Especially, the addition of 2mol% of Na$_{2}$O improved the humidity-sensing characteristics such as sensitivity and linearity in the whole range between 30 and 90 %RH (Percentage Relative Humidity)y)

• Review of Culture and Economy
• /
• v.20 no.2
• /
• pp.3-18
• /
• 2017

The purpose of this study is to analyze changes in work autonomy of content industry workers using Korea Working Conditions Survey(2010, 2014) and difference-differences estimation method. The results find that there was no significant change in the work autonomy (work order, work method, work speed) of the content industry worker in In the overall sample. On the other hand, analyzing the sample of 30 or more employee establishment size shows that work autonomy of the content industry worker is greatly reduced. Also, work autonomy is high when the rank or capability is high, whereas work autonomy decreases when the establishment size is large. This study implies that the content industry workers have shown quantitatively the reduction of work autonomy. It also suggests that compensation and management systems are needed to enhance the competitiveness of the content industry.

• Journal of Korean Academy of Nursing Administration
• /
• v.19 no.1
• /
• pp.108-117
• /
• 2013

Purpose: To analyze trends in salaries for registered nurses when compared with salaries for elementary school teachers from 2002 to 2009 and identify salary gaps of nurses according to workplace size and geographic location. Methods: Data were obtained from the Occupational Employment Statistics collected by the Korea Employment Information Services each year from 2002 to 2009. The study sample consisted of 2,281 registered nurses and 2,578 elementary school teachers. Linear multiple regression analyses were conducted to analyze salary trends and differences. Results: Elementary school teachers had higher monthly salaries than nurses with a baccalaureate degree after adjusting for years of work. Salary differences increased significantly by 40,000 won every year (p<.001). Nurses working in large facilities in Seoul had the highest salaries, whereas those in small/medium, non-Seoul facilities had the lowest salaries consistently over time. Salary differences between the two groups increased by 47,000 won every year (p=.001); salary differences between nurses in large, non-Seoul facilities and those in small/medium, non-Seoul facilities also increased by 40,000 won annually (p=.001). Conclusion: Geographical imbalances in the nurse workforce and nurse shortages in small/medium, non-capital facilities could be reduced by increasing the salary of nurses working in those facilities.

• Journal of Powder Materials
• /
• v.25 no.2
• /
• pp.126-131
• /
• 2018

In the present study, we investigate the effects of milling time and the addition of a process control agent (PCA) on the austenite stability of a nanocrystalline Fe-7%Mn alloy by XRD analysis and micrograph observation. Nanocrystalline Fe-7%Mn alloys samples are successfully fabricated by spark plasma sintering. The crystallite size of ball-milled powder and the volume fraction of austenite in the sintered sample are calculated using XRD analysis. Changes in the shape and structure of alloyed powder according to milling conditions are observed through FE-SEM. It is found that the crystallite size is reduced with increasing milling time and amount of PCA addition due to the variation in the balance between the cold-welding and fracturing processes. As a result, the austenite stability increased, resulting in an exceptionally high volume fraction of austenite retained at room temperature.

• Journal of Computational Design and Engineering
• /
• v.1 no.4
• /
• pp.223-232
• /
• 2014

This paper describes a variant of the extended Gaussian image based registration algorithm for point clouds with surface color information. The method correlates the distributions of surface normals for rotational alignment and grid occupancy for translational alignment with hue filters applied during the construction of surface normal histograms and occupancy grids. In this method, the size of the point cloud is reduced with a hue-based down sampling that is independent of the point sample density or local geometry. Experimental results show that use of the hue filters increases the registration speed and improves the registration accuracy. Coarse rigid transformations determined in this step enable fine alignment with dense, unfiltered point clouds or using Iterative Common Point (ICP) alignment techniques.