• Title/Summary/Keyword: soft breakdown

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Characteristics of Hardness and Elastic Modulus of PMMA Film using Nano-Tribology (Nanotribology를 이용한 PMMA 박막의 Hardness와 Elastic Modulus 특성 연구)

  • Kim, Soo-In;Kim, Hyun-Woo;Noh, Seong-Cheol;Yoon, Duk-Jin;Chang, Hong-Jun;Lee, Jong-Rim;Lee, Chang-Woo
    • Journal of the Korean Vacuum Society
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    • v.18 no.5
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    • pp.372-376
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    • 2009
  • In the modern semiconductor industry, lithography process is used to construct specific patterns. However, due to the decreasing of line width, these days, more and more researchers are interested in PMMA(Poly Methyl Methacrylate) lithography by using e-beam instead of the prior method, PR(Photoresist) lithography by using UV(Ultra-Violet). Additionally, the patterns constructed by lithography are collapsed during the process of cleansing remnants and the resistance against the breakdown of the patterns is known to be proportional to the elastic modulus of pattern-constructing materials. In this research, we measured the change of hardness and elastic modulus of PMMA film surface according to the change of time spent to soft-bake the PMMA film. During the measurement, we controlled the tip pressure from $25{\mu}N$ to $8,500{\mu}N$ having intervals that are $134.52{\mu}N$. For these measurements, we used the Triboindenter from Hysitron to gauge the hardness and elastic modulus and the tip we used was Berkovich diamond Tip.

Simple Fabrication of Micromixer Based on Non-Equilibrium Electrokinetics in Micro/Nano Hybrid Fluidic System (단순공정으로 제작된 마이크로/나노 하이브리드 채널의 불균형 동전기성을 이용한 미세혼합기 연구)

  • Yu, Samuel;Kim, Sun-Min
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.4
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    • pp.385-390
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    • 2011
  • In this study, we developed a micromixer based on the non-equilibrium electrokinetics at the junction of a microchannel and nanochannel. Two fluid streams were mixed by an electro-osmotic flow and a vortex flow created as a result of the non-equilibrium electrokinetics at the junction of the microchannel and nanochannel. Initially, the microchannel was fabricated using Polydimethylsiloxane (PDMS) by the general soft lithography process and the nanochannel was created at a specific position on the microchannel by applying a high voltage. To evaluate the mixing performance of the micromixer, fluorescent distribution was analyzed by using the fluorescent dye, Rhodamine B. About 90% mixing was achieved with this novel micromixer, and this micromixer can be used in microsystems for biochemical sample analysis.

Through Knee Amputation: Technique Modifications and Surgical Outcomes

  • Albino, Frank P.;Seidel, Rachel;Brown, Benjamin J.;Crone, Charles G.;Attinger, Christopher E.
    • Archives of Plastic Surgery
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    • v.41 no.5
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    • pp.562-570
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    • 2014
  • Background Knee disarticulations (KD) are most commonly employed following trauma or tumor resection but represent less than 2% of all lower extremity amputations performed in the United States annually. KDs provide enhanced proprioception, a long lever arm, preservation of adductor muscle insertion, decreased metabolic cost of ambulation, and an end weight-bearing stump. The role for KDs in the setting of arterial insufficiency or overwhelming infection is less clear. The purpose of this study is to describe technique modifications and report surgical outcomes following KDs at a high-volume Limb Salvage Center. Methods A retrospective study of medical records for all patients who underwent a through-knee amputation performed by the senior author (C.E.A.) between 2004 and 2012 was completed. Medical records were reviewed to collect demographic, operative, and postoperative information for each of the patients identified. Results Between 2004 and 2012, 46 through-knee amputations for 41 patients were performed. The mean patient age was 68 and indications for surgery included infection (56%), arterial thrombosis (35%), and trauma (9%). Postoperative complications included superficial cellulitis (13%), soft tissue infection (4%), and flap ischemia (4%) necessitating one case of surgical debridement (4%) and four transfemoral amputations (9%). 9 (22%) patients went on to ambulate. Postoperative ambulation was greatest in the traumatic cohort and for patients less than 50 years of age, P<0.05. Alternatively, diabetes mellitus and infection reduced the likelihood of postoperative ambulation, P<0.01. Conclusions Knee disarticulations are a safe and effective alternative to other lower extremity amputations when clinically feasible. For patient unlikely to ambulate, a through-knee amputation maximizes ease of transfers, promotes mobility by providing a counterbalance, and eliminates the potential for knee flexion contracture with subsequent skin breakdown.

Effects of Electrostatic Discharge Stress on Current-Voltage and Reverse Recovery Time of Fast Power Diode

  • Bouangeune, Daoheung;Choi, Sang-Sik;Cho, Deok-Ho;Shim, Kyu-Hwan;Chang, Sung-Yong;Leem, See-Jong;Choi, Chel-Jong
    • JSTS:Journal of Semiconductor Technology and Science
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    • v.14 no.4
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    • pp.495-502
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    • 2014
  • Fast recovery diodes (FRDs) were developed using the $p^{{+}{+}}/n^-/n^{{+}{+}}$ epitaxial layers grown by low temperature epitaxy technology. We investigated the effect of electrostatic discharge (ESD) stresses on their electrical and switching properties using current-voltage (I-V) and reverse recovery time analyses. The FRDs presented a high breakdown voltage, >450 V, and a low reverse leakage current, < $10^{-9}$ A. From the temperature dependence of thermal activation energy, the reverse leakage current was dominated by thermal generation-recombination and diffusion, respectively, at low and high temperature regions. By virtue of the abrupt junction and the Pt drive-in for the controlling of carrier lifetime, the soft reverse recovery behavior could be obtained along with a well-controlled reverse recovery time of 21.12 ns. The FRDs exhibited excellent ESD robustness with negligible degradations in the I-V and the reverse recovery characteristics up to ${\pm}5.5$ kV of HBM and ${\pm}3.5$ kV of IEC61000-4-2 shocks. Likewise, transmission line pulse (TLP) analysis reveals that the FRDs can handle the maximum peak pulse current, $I_{pp,max}$, up to 30 A in the forward mode and down to - 24 A in the reverse mode. The robust ESD property can improve the long term reliability of various power applications such as automobile and switching mode power supply.

Flour Characteristics and End-Use Quality of Korean Wheat Cultivars I. Flour Characteristics (국산밀 품종의 밀가루 특성과 가공적성 I. 밀가루 특성)

  • Kang, Chon-Sik;Park, Chul Soo;Park, Jong-Chul;Kim, Hag-Sin;Cheong, Young-Keun;Kim, Kyung-Ho;Kim, Ki-Jong;Park, Ki-Hoon;Kim, Jung-Gon
    • Korean Journal of Breeding Science
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    • v.42 no.1
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    • pp.61-74
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    • 2010
  • Flour characteristics of 26 Korean wheat cultivars (KWC) were evaluated to assess consumer satisfaction with 6 imported wheat and 5 commercial wheat flours. In physical characteristics of flours, Particle size of SW (soft white) was similar to Dahong, Geuru, Milsung, Olgeuru, Seodun, Tapdong, and Uri. DNS (dark northern spring) was similar to Jeokjoong, Joeun, Sukang, and Younbaek. Ash and damaged starch content of KWC was similar to that of imported wheat and commercial flour (Com), but lightness value ($L^*$) were lower than those of Com. Particle size of flour positively correlated with ash, damaged starch, and lightness value ($L^*$) of flour. L ($^*$) value of flour negatively correlated with ash, damaged starch, and particle size of flour. In protein characteristics, Protein content of SW and commercial flour for baking cookie (Com5) was similar to Baekjoong, Jinpoom, Milsung, Olgeuru, Saeol, and Uri. HRW (hard red winter) and commercial flour for baking bread (Com3) was similar to Hanbaek, Joeun, Jopoom, Keumkang, and Sukang. SDS sedimentation volume based on a constant flour weight (SDSS) of KWC was lower than those of DNS and Com3. Mixograph water absorption of KWC similar to imported wheat and Com. Mixing time and maximum dough height (Hm) of KWC were higher than those of imported wheat and Com. Protein content positively correlated with SDS sedimentation volume and water absorption of mixograph. SDS-sedimentation volume positively correlated with water absorption of mixograph, mixing time of mixograph, and height of dough development. In starch characteristics of flour, ASW (Australian standard white) flours showed lower amylose content, higher peak viscosity, breakdown, and setback in pasting properties than other flours. KWV flours showed higher amylose content and lower peak viscosity than those of AH (Australian hard), ASW, commercial flour for making white salted noodles (Com1), commercial flour for making yellow alkaline noodles (Com2), and Com3.

The Application of NIRS for Soil Analysis on Organic Matter Fractions, Ash and Mechanical Texture

  • Hsu, Hua;Tsai, Chii-Guary;Recinos-Diaz, Guillermo;Brown, John
    • Proceedings of the Korean Society of Near Infrared Spectroscopy Conference
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    • 2001.06a
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    • pp.1263-1263
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    • 2001
  • The amounts of organic matter present in soil and the rate of soil organic matter (SOM) turnover are influenced by agricultural management practice, such as rotation, tillage, forage plow down direct seeding and manure application. The amount of nutrients released from SOM is highly dependent upon the state of the organic matter. If it contains a large proportion of light fractions (low-density) more nutrients will be available to the glowing crops. However, if it contains mostly heavy fractions (high-density) that are difficult to breakdown, then lesser amounts of nutrients will be available. The state of the SOM and subsequent release of nutrients into the soil can be predicted by NIRS as long as a robust regression equation is developed. The NIRS method is known for its rapidity, convenience, simplicity, accuracy and ability to analyze many constituents at the same time. Our hypothesis is that the NIRS technique allows researchers to investigate fully and in more detail each field for the status of SOM, available moisture and other soil properties in Alberta soils for precision farming in the near future. One hundred thirty one (131) Alberta soils with various levels (low 2-6%, medium 6-10%, and high >10%) of organic matter content and most of dry land soils, including some irrigated soils from Southern Alberta, under various management practices were collected throughout Northern, Central and Southern Alberta. Two depths (0- 15 cm and 15-30 cm) of soils from Northern Alberta were also collected. These air-dried soil samples were ground through 2 mm sieve and scanned using Foss NIR System 6500 with transport module and natural product cell. With particle size above 150 microns only, the “Ludox” method (Meijboom, Hassink and van Noorwijk, Soil Biol. Biochem.27: 1109-1111, 1995) which uses stable silica, was used to fractionate SOM into light, medium and heavy fractions with densities of <1.13, 1.13-1.37 and >1.37 respectively, The SOM fraction with the particle size below 150 microns was discarded because practically, this fraction with very fine particles can't be further separated by wet sieving based on density. Total organic matter content, mechanical texture, ash after 375$^{\circ}C$, and dry matter (DM) were also determined by “standard” soil analysis methods. The NIRS regression equations were developed using Infra-Soft-International (ISI) software, version 3.11.

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Clinical Study on Prenatal care, and Dietary Intakes for Pregnant Women and new Mothers (임산부의 산전관리와 산욕기 영양실태에 관한 연구)

  • Chia, Soon-Hyang;Park, Chai-Soon
    • Journal of Nutrition and Health
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    • v.9 no.4
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    • pp.36-46
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    • 1976
  • This study was projected to provide basic data on prenatal care for future direction in maternity and child care, and also to investigate the diet of women during pregnancy and the period directly afterwards in order to offer to mothers appropriate advice for the improvement of nutritional standards. A clinical study on prenatal care was based on 1054 delivery cases. A nutritional survey was performed on 174 mothers admitted to the department of obstetrics at St. Mary's Hospital during the period of March, 1975 to February, 1976. The results obtained are summarized as follows; I. Clinical study on prenatal care 1) The age distribution showed 59.4% of the mothers were between the ages of 25 to 29 years old. 2) The gestational period was highest between the 37th and 40th gestational weeks. 33.7% of the mothers were primigravidae and 31.8% of them primiparae. 3) 41.3% of the mothers had not received prenatal care or had only received it once before. 4) Induced deliveries were 61.8% and spontantaneous deliveries 38.2%. 61.9% of the mothers had received prenatal care, while those without prenatal care accounted for 61.6% of the total induced deliveries. 5) Low birth weights were 7.7% and 5.0% of the mothers had received prenatal care, while 11.5% had no prenatal care. 6) There were 1.13% of still births, 0.32% of the mothers had prenatal care and the remainder did not have prenatal care. 7) Of those receiving prenatal care, 2.1% showed in the $0{\sim}3$ Apgar score group, 6.3% in the $4{\sim}6$ Apgar score group, and 91.6% in the $7{\sim}10$ Apgar score group. Among the non-prenatally cared for group 5.0% of the newborns were in the $0{\sim}3$ Apgar score group, 9.7% were in $4{\sim}6$ Apgar score group and 85.3% were in the $7{\sim}10$ Apgar score group. 8) Obstetrical complications were developed in 11.86% of the pregnant women when they were hospitalized. Among the group receiving the prenatal care 8.1% of the mothers had obstetrical complications. In the group without prenatal care 17.16% of the mothers had obstetrical complications. The most common obstetrical complication was malpresentation. 9) The first prenatal care was received between the 37th and 40th gestationl weeks. II. Food intake during pregnancy The following are the results from the questionnaires of the mothers concerning diets during pregnancy; 1) Main meals and snacks In 32.2% of the cases, their main meals during the diet amounted to more than was usually eaten at other times. In 67.8% of the cases, their main meals during the diet were the same as that usually eaten. In 22.4% of the cases, snacks during the diet amounted to more than usually eaten at other times. In 77.6% of the cases, snacks during the diet were the same as usually eaten. 2) Itemized list The mothers made a special effort to include certain items in their diets, the following is a breakdown of those items; a. egg, meat, fish 33.3% b. fruit, vegetables 32.2%. c. milk, fruit juice 18.4% d. cake, bread 2.9% e. nothing special 13.2% 3) Milk 44.8% of the mothers had at least one cup of milk everyday. 33.4% of the mothers had at least one cup of milk on occasion. 15.5% of the mothers did not have any milk. 4) Vitamins 39.7% of the mothers had vitamins everyday. 24.7% of the mothers had vitamins occasionally. 35.6% of the mothers did not have any vitamins. 5) Anemic symptoms 9.2% of the mothers very often had anemic symptoms during pregnancy. 39.1% of the mothers often had anemic symptoms during pregnancy. 51.7% of the mothers did not have anemic symptoms at all. 6) Taboos on food 23% of the mothers recognized 'taboos' on food during pregnancy 27% of the mothers displayed on uncertainty about the 'taboos' on food during pregnancy 50% of the mothers displayed indifference toward the taboos. III. Nutritional survey on the new mothers diet. 1) The diets for new mothers can be divided into four categories, such as general diet, low sodium diet, soft diet and liquid diet. 2) Cooked rice and seaweed soup were the main foods for the new mothers as has been the traditional diet for Korean mothers. 3) The average diet contained 1,783g. And the average consumption of the basic food groups per capita per day was 1,265g for cereals and grains, 456g for meats and legumes, 58g for fruits and vegetables, 0g for milk and fish and 4g for fats and oils. 4) In addition to the 1,783g of food in the main diet there was also 142.8g of food taken as snacks. 5) The average daily consumption of calories and nutrients was 2,697 Kcal and 123.4g for proteins, 44.9g for fats, 718.2mg for calcium, 14mg for iron, 2,101.4 I.U. for vitamin A, 0.43mg for thiamine, 1.02mg for riboflavin, 15.88mg for niacin, 5.26mg for ascorbic acid. When these figures are compared with the recommended allowances for new mothers in Korea, the calories and nutrients taken in were satisfactory. But the intake of minerals and vitamins was below the recommended allowance.

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Physicochemical Properties of Commercial Sweet Potato Starches (시판 고구마전분의 이화학적 특성)

  • Baek, Man-Hee;Cha, Dong-Su;Park, Hyun-Jin;Lim, Seung-Taik
    • Korean Journal of Food Science and Technology
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    • v.32 no.4
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    • pp.755-762
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    • 2000
  • Physicochemical properties of commercial sweet potato starches manufactured by 7 different companies were investigated in comparison with corn and potato starches. Crude ash and protein content varied from 0.36 to 1.02%, and from 0.04 to 0.14% based on dry weight, respectively. The protein contents were relatively smaller than that of corn or potato starch. But whiteness of the sweet potato starches was less than that of corn or potato starch. Mean diameter of the sweet potato starch granules varied from 14.23 to $21.08\;{\mu}m$ depending on the company and all sweet potato starches showed bimodal size distributions. Pasting viscosity measured by Rapid Viscoanalyzer(RVA) also showed variations among the starches of different companies. The starch from D company in Korea had the lowest pasting temperature$(74.00^{\circ}C)$ whereas the starch from a phillippine company(P) did the highest one$(80.35^{\circ}C)$. The peak viscosity of sweet potato starches was higher than that of corn starch but lower than that of potato starch. The D company starch also showed the highest peak viscosity(2283 cp) among the starches tested. Paste breakdown by hot shearing ranged from 524 cp (S company) to 1279 cp (HL company). Textural properties of the starch gels appeared significantly different among the starches of different manufacturers. The greatest hardness of the gel was $137.90\;g_{f}$ at 1 day storage whereas the lowest value was $31.53\;g_{f}$. Except the starches from 2 companies (P and S), the sweet potato starches formed very soft and weak gels. P or S company starches formed the gels similar to potato starch. Syneresis by freeze-thawing treatments appeared less for sweet potato starch gels than that for corn starch gels, but greater than that for potato starch gel. The overall properties of the sweet potato starches varied by the manufacturing companies, and ranged between those of corn and potato starches.

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