• Title/Summary/Keyword: density index

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Atomic Layer Deposition of Al2O3 Thin Films Using Dimethyl Aluminum sec-Butoxide and H2O Molecules

  • Jang, Byeonghyeon;Kim, Soo-Hyun
    • Korean Journal of Materials Research
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    • v.26 no.8
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    • pp.430-437
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    • 2016
  • Aluminum oxide ($Al_2O_3$) thin films were grown by atomic layer deposition (ALD) using a new Al metalorganic precursor, dimethyl aluminum sec-butoxide ($C_{12}H_{30}Al_2O_2$), and water vapor ($H_2O$) as the reactant at deposition temperatures ranging from 150 to $300^{\circ}C$. The ALD process showed typical self-limited film growth with precursor and reactant pulsing time at $250^{\circ}C$; the growth rate was 0.095 nm/cycle, with no incubation cycle. This is relatively lower and more controllable than the growth rate in the typical $ALD-Al_2O_3$ process, which uses trimethyl aluminum (TMA) and shows a growth rate of 0.11 nm/cycle. The as-deposited $ALD-Al_2O_3$ film was amorphous; X-ray diffraction and transmission electron microscopy confirmed that its amorphous state was maintained even after annealing at $1000^{\circ}C$. The refractive index of the $ALD-Al_2O_3$ films ranged from 1.45 to 1.67; these values were dependent on the deposition temperature. X-ray photoelectron spectroscopy showed that the $ALD-Al_2O_3$ films deposited at $250^{\circ}C$ were stoichiometric, with no carbon impurity. The step coverage of the $ALD-Al_2O_3$ film was perfect, at approximately 100%, at the dual trench structure, with an aspect ratio of approximately 6.3 (top opening size of 40 nm). With capacitance-voltage measurements of the $Al/ALD-Al_2O_3/p-Si$ structure, the dielectric constant of the $ALD-Al_2O_3$ films deposited at $250^{\circ}C$ was determined to be ~8.1, with a leakage current density on the order of $10^{-8}A/cm^2$ at 1 V.

Still life with less: North Korean young adult defectors in South Korea show continued poor nutrition and physique

  • Choi, Seul-Ki;Park, Sang-Min;Joung, Hyo-Jee
    • Nutrition Research and Practice
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    • v.4 no.2
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    • pp.136-141
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    • 2010
  • North Korean defectors who settle in South Korea have experienced severe food shortage and transition of food environment which could affect their health status. However, little is known about their anthropometric measurements and dietary intake after settlement in South Korea. The purpose of this study is to compare anthropometric measurements and dietary intake between North Korean young adults who defected to South Korea and those of South Koreans. We hypothesized that North Korean young adults' physiques and dietary intake would be poorer than that of South Koreans. We compared anthropometric measurements and dietary intake from 3-day food records in a cross-sectional study of 103 North Korean young adult defectors, aged 12 to 24 and 309 South Korean subjects. North Korean subjects were significantly shorter (4.9 to 10.8 cm) and lighter (6.0 to 12.5 kg) than the control group. Body mass index were significantly different between North and South Korean groups only in men. North Korean young adult defectors had lower mean daily intakes of energy and most nutrients and food groups compared to the control group, while North Korean subjects had higher nutrient density diet than that of South Koreans. The proportion of subjects who had dietary intakes of nutrients of less than the Estimated Average Requirement was higher in North Korean subjects than in controls except for in the cases of vitamin A and vitamin C. In conclusion, we recommend providing nutrition support programs for North Korean young adult defectors to secure adequate nutrient intake.

Investigation of Properties of the PET Film Dependent on the Biaxial Stretching (PET 필름의 이축연신에 따른 물성변화 연구)

  • Lee, Jung-Gyu;Park, Sang-Ho;Kim, Seong-Hun
    • Polymer(Korea)
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    • v.34 no.6
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    • pp.579-587
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    • 2010
  • To investigate the properties of PET films, PET films were extruded at various temperature above $T_m$ and quenched at $18^{\circ}C$ for amorphous sheet, and stretched along a direction defined as the machine direction (MD) with a transverse direction (TD) above $T_g$ at various stretching ratios and then annealed at various temperatures produced by SKC PET line. Thermal shrinkage of MD and TD increased with decreasing annealing temperature and extruding temperature, and increasing stretching ratio. The degree of crystallinity, density, heat of fusion (${\Delta}H$) and pre-melting point ($T_m'$) increased with increasing annealing temperature and extruding temperature. Number average molecular weight ($M_n$) and intrinsic viscosity decreased with increasing extruding temperature. Tensile strength and modulus increased with increasing stretching ratio, however decreased with increasing annealing temperature. Reflective index of both stretching and thickness direction increased with increasing stretching ratio and annealing temperature.

The Analysis of Patterns and Risk Factors of Newly Developed Vertebral Compression Fractures after Percutaneous Vertebroplasty

  • Yoo, Chai Min;Park, Kyung Bum;Hwang, Soo Hyun;Kang, Dong Ho;Jung, Jin Myung;Park, In Sung
    • Journal of Korean Neurosurgical Society
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    • v.52 no.4
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    • pp.339-345
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    • 2012
  • Objective : The purpose of this study was to investigate the patterns and the risk factors of newly developed vertebral compression fractures (VCFs) after percutaneous vertebroplasty (PVP). Methods : We performed a retrospective review of the 244 patients treated with PVP from September 2006 to February 2011. Among these patients, we selected 49 patients with newly developed VCFs following PVP as the new VCFs group, and the remaining 195 patients as the no VCFs group. The new VCFs group was further divided into 2 groups : an adjacent fractures group and a nonadjacent fractures group. The following data were collected from the groups : age, gender, body weight/height, body mass index (BMI), bone mineral density (BMD) score of the spine and femur, level of initial fracture, restoration rate of anterior/middle vertebral height, and intradiscal cement leakage, volume of polymethylmethacrylate (PMMA). Results : Age, gender, mean body height/weight, mean BMI and volume of PMMA of each of the group are not statistically significantly associated with fractures. In comparison between the new VCFs group and the no VCFs group, lower BMD, intradiscal cement leakage and anterior vertebral height restoration were the significant predictive factors of the fracture. In addition, new VCFs occurrence at the adjacent spines was statistically significant, when the initial fracture levels were confined to the thoracolumbar junction, among the subgroups of new VCFs. Conclusion : Lower spinal BMD, the greater anterior vertebral height restoration rate and intradiscal cement leakage were confirmed as risk factors for newly formed VCFs after PVP.

Review and Proposition of Biological Indicators for a New Ecological Grading System of Tidal Flats in Korea (한국의 갯벌 생태등급도 개발을 위한 생물학적 지시자의 검토와 제안)

  • Yoo, Jae-Won;Lee, Chang-Gun;Kho, Byung-Seol;Lee, Si-Wan;Han, Dong-Uk;Choi, Keun-Hyung;Kim, Chang-Soo;Hong, Jae-Sang
    • Ocean and Polar Research
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    • v.33 no.1
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    • pp.85-97
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    • 2011
  • The tidal flats of Korea today have reduced by 40% in size compared to 1964. To manage this important habitat properly, development of well-organized and nationwide-applicable grading systems is required. There have been several assessment systems proposed previously in Korea, but they are critically flawed in that selected biological indicators are not adequate and grading criteria are obscure and arbitrary. We reviewed the indicators used in these previous evaluation systems (e.g., diversity indices, quantity and quality of benthic macrofauna, halophytes, water birds, etc.) and subsequently proposed new indicators and an improved grading scheme. For the quantitative assessment of macrobenthic community, biomass reflecting production and ecosystem function is recommended over density, which is much less discriminatory among habitats. Of biodiversity indices used, within-, between-habitat and regional biodiversity indices that accurately reflect sampling efforts are suggested. In addition, we proposed to include species rarity, ecosystem engineers, and the ecological quality index ISEP (Inverse function of Shannon-Wiener Evenness Proportion). As for halophytes, their low spatial coverage on benthic habitat suggests that their presence can be used as an ecological indicator of benthic habitat, regardless of their protective status. We stress the need to introduce 1) quantile approach for quantitative indicators (e.g., diversity, biomass, etc.) in relation to grading, 2) presence-absence approach for spatial or aggregate indicators (e.g., boundaries of halophytes and feeding ground of water birds) and 3) benthic habitat mapping that combines all of these indicators.

Long-term effects of gonadotropin-releasing hormone analogs in girls with central precocious puberty

  • Kim, Eun Young
    • Clinical and Experimental Pediatrics
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    • v.58 no.1
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    • pp.1-7
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    • 2015
  • Gonadotropin-releasing hormone analogs (GnRHa) are widely used to treat central precocious puberty (CPP). The efficacy and safety of GnRHa treatment are known, but concerns regarding long-term complications are increasing. Follow-up observation results after GnRHa treatment cessation in female CPP patients up to adulthood showed that treatment (especially <6 years) was beneficial for final adult height relative to that of pretreated or untreated patients. Puberty was recovered within 1 year after GnRHa treatment discontinuation, and there were no abnormalities in reproductive function. CPP patients had a relatively high body mass index (BMI) at the time of CPP diagnosis, but BMI standard deviation score maintenance during GnRHa treatment seemed to prevent the aggravation of obesity in many cases. Bone mineral density decreases during GnRHa treatment but recovers to normal afterwards, and peak bone mass formation through bone mineral accretion during puberty is not affected. Recent studies reported a high prevalence of polycystic ovarian syndrome in CPP patients after GnRHa treatment, but it remains unclear whether the cause is the reproductive mechanism of CPP or GnRHa treatment itself. Studies of the psychosocial effects on CPP patients after GnRHa treatment are very limited. Some studies have reported decreases in psychosocial problems after GnRHa treatment. Overall, GnRHa seems effective and safe for CPP patients, based on long-term follow-up studies. There have been only a few long-term studies on GnRHa treatment in CPP patients in Korea; therefore, additional long-term follow-up investigations are needed to establish the efficacy and safety of GnRHa in the Korean population.

The Effect of Long-term Organic Matter Addition on the Physicochemical Properties of Paddy Soil (답토양(沓土壤)에서 퇴비연용(堆肥連用)이 토양(土壤)의 이화학적성질(理化學的性質)에 미치는 영향(影響))

  • Shin, Jae Sung;Shin, Yong Hwa
    • Korean Journal of Soil Science and Fertilizer
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    • v.8 no.1
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    • pp.19-23
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    • 1975
  • In order to find out the effect of long-term annual additions of organic matter on the physico-chemical properties of paddy soil, the soil with and without compost application has been analysed. 1. There was no significant difference in the particle size distribution between compost and uncompost treatment, however, hydraulic conductivity, sedimention volume were remarkedly increased in compost. 2. Bulk density and soil strength were decreased in organic matter additions, but porosity increased. 3. Relative to Atterberg Limits, liquid limit, plastic limit, and elastic index were increased in compost. 4. Aggregate size distribution was slightly increased in additions of organic matter. 5. Regarding to chemical properties, pH, organic matter content, C.E.C. and extractable cation were increased in organic matter additions.

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A Study on Nutrient Intake During Pregnancy of Women of Premature Delivery (I) (미숙아를 출산한 산모의 임신시 영양소 섭취실태에 관한 연구 (I))

  • Lee, Seung-Lim;Chang, Yu-Kyung
    • Korean Journal of Community Nutrition
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    • v.12 no.6
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    • pp.752-760
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    • 2007
  • Inadequate nutritional status of pregnancy can cause underweight and premature birth, undergrowth and deliverance of physically and mentally defected babyies. The purpose of this study is to provide guidelines for preventing preterm delivery in the aspect of nutritional factors. The nutrient intakes were compared between a preterm delivery group and a normal term delivery group to recognize risk factors of preterm delivery. The results obtained are summarized as follows. The pregnancy period was statistically longer in the normal term group (p<0.0001). Weight increase was statistically higher in the normal term group (p<0.0001). Calories (p<0.05), carbohydrates (p<0.0005), dietary fibers (p<0.0001), potassium (p<0.0005), vitamin $B_1$ (p<0.0005), vitamin $B_6$ (p<0.05), vitamin C (p<0.0001), and folic acid (p<0.05) intakes were statistically higher in the normal term group. Nutrient density of vitamin $B_1$ (p<0.05) and vitamin C (p<0.0001) in the normal term group was statistically higher. Nutrient adequacy ratio of zinc (p<0.05), vitamin $B_1$ (p<0.05) and folic acid (p<0.05) were statistically higher in the normal term group. Index of Nutritional Quality of vitamin $B_1$ (p<0.05) and vitamin C (p<0.0001) were statistically higher in the normal term group. In this study, the normal term delivery showed higher intakes of calories, carbohydrates, dietary fiber, crude fiber, potassium, vitamin $B_1$, vitamin $B_6$ vitamin C and folic acid than the preterm delivery group. Deficiencies in various nutrients may lead to preterm delivery, therefore, balanced nutrient intake is recommended to prevent preterm delivery.

Skeletal Ryanodine Receptor 1-Heterozygous PSE (Pale, Soft and Exudative) Meat Contains a Higher Concentration of Myoglobin than Genetically Normal PSE Meat in Pigs

  • Obi, T.;Matsumoto, M.;Miyazaki, K.;Kitsutaka, K.;Tamaki, M.;Takase, K.;Miyamoto, A.;Oka, T.;Kawamoto, Y.;Nakada, T.
    • Asian-Australasian Journal of Animal Sciences
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    • v.23 no.9
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    • pp.1244-1249
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    • 2010
  • Comparisons of properties between skeletal ryanodine receptor 1 (sRyR1)-heterozygous-mutated and normal types of meat were carried out in pigs using PSE (pale, soft and exudative) meat found during the butchering process. All samples considered to be PSE meat showed irregular running and disorder of the muscle fibers and a wider inter-fiber space upon light microscopic observation. Electron microscopy revealed disintegration, twisting, and disorder of the myofibril arrangement and elimination of the Z line in PSE meat, compared with normal meat. Meat property tests demonstrated greater decreases in water holding capacity, moisture and sarcoplasmic protein, and higher $L^*$ values for the meat color index in PSE meat than in normal meat, but there were no differences in these factors between genetically normal and sRyR1-heterozygous PSE meat. On the other hand, higher $a^*$ and $b^*$ values were observed in sRyR1-heterozygous than in normal PSE meat, and similar alterations to the a* value were observed in terms of the amount of myoglobin and density of the 17-kDa protein band, corresponding to the molecular mass of myoglobin, on SDS-PAGE gels. These results suggest that sRyR1-heterozygous PSE pork contains much more myoglobin than genetically normal PSE meat.

Impact of Wind Profiler Data Assimilation on Wind Field Assessment over Coastal Areas

  • Park, Soon-Young;Lee, Hwa-Woon;Lee, Soon-Hwan;Kim, Dong-Hyeok
    • Asian Journal of Atmospheric Environment
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    • v.4 no.3
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    • pp.198-210
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    • 2010
  • Precise analysis of local winds for the prediction of atmospheric phenomena in the planetary boundary layer is extremely important. In this study, wind profiler data with fine time resolution and density in the lower troposphere were used to improve the performance of a numerical atmospheric model of a complex coastal area. Three-dimensional variational data assimilation (3DVAR) was used to assimilate profiler data. Two experiments were conducted to determine the effects of the profiler data on model results. First, we performed an observing system experiment. Second, we implemented a sensitivity test of data assimilation intervals to extend the advantages of the profiler to data assimilation. The lowest errors were observed when using both radio sonde and profiler data to interpret vertical and surface observation data. The sensitivity to the assimilation interval differed according to the synoptic conditions when the focus was on the surface results. The sensitivity to the weak synoptic effect was much larger than to the strong synoptic effect. The hourly-assimilated case showed the lowest root mean square error (RMSE, 1.62 m/s) and highest index of agreement (IOA, 0.82) under weak synoptic conditions, whereas the statistics in the 1, 3, and 6 hourly-assimilated cases were similar under strong synoptic conditions. This indicates that the profiler data better represent complex local circulation in the model with high time and vertical resolution, particularly when the synoptic effect is weak.