• Title/Summary/Keyword: two-phase system

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Evaluation of the Positional Uncertainty of a Liver Tumor using 4-Dimensional Computed Tomography and Gated Orthogonal Kilovolt Setup Images (사차원전산화단층촬영과 호흡연동 직각 Kilovolt 준비 영상을 이용한 간 종양의 움직임 분석)

  • Ju, Sang-Gyu;Hong, Chae-Seon;Park, Hee-Chul;Ahn, Jong-Ho;Shin, Eun-Hyuk;Shin, Jung-Suk;Kim, Jin-Sung;Han, Young-Yih;Lim, Do-Hoon;Choi, Doo-Ho
    • Radiation Oncology Journal
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    • v.28 no.3
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    • pp.155-165
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    • 2010
  • Purpose: In order to evaluate the positional uncertainty of internal organs during radiation therapy for treatment of liver cancer, we measured differences in inter- and intra-fractional variation of the tumor position and tidal amplitude using 4-dimentional computed radiograph (DCT) images and gated orthogonal setup kilovolt (KV) images taken on every treatment using the on board imaging (OBI) and real time position management (RPM) system. Materials and Methods: Twenty consecutive patients who underwent 3-dimensional (3D) conformal radiation therapy for treatment of liver cancer participated in this study. All patients received a 4DCT simulation with an RT16 scanner and an RPM system. Lipiodol, which was updated near the target volume after transarterial chemoembolization or diaphragm was chosen as a surrogate for the evaluation of the position difference of internal organs. Two reference orthogonal (anterior and lateral) digital reconstructed radiograph (DRR) images were generated using CT image sets of 0% and 50% into the respiratory phases. The maximum tidal amplitude of the surrogate was measured from 3D conformal treatment planning. After setting the patient up with laser markings on the skin, orthogonal gated setup images at 50% into the respiratory phase were acquired at each treatment session with OBI and registered on reference DRR images by setting each beam center. Online inter-fractional variation was determined with the surrogate. After adjusting the patient setup error, orthogonal setup images at 0% and 50% into the respiratory phases were obtained and tidal amplitude of the surrogate was measured. Measured tidal amplitude was compared with data from 4DCT. For evaluation of intra-fractional variation, an orthogonal gated setup image at 50% into the respiratory phase was promptly acquired after treatment and compared with the same image taken just before treatment. In addition, a statistical analysis for the quantitative evaluation was performed. Results: Medians of inter-fractional variation for twenty patients were 0.00 cm (range, -0.50 to 0.90 cm), 0.00 cm (range, -2.40 to 1.60 cm), and 0.00 cm (range, -1.10 to 0.50 cm) in the X (transaxial), Y (superior-inferior), and Z (anterior-posterior) directions, respectively. Significant inter-fractional variations over 0.5 cm were observed in four patients. Min addition, the median tidal amplitude differences between 4DCTs and the gated orthogonal setup images were -0.05 cm (range, -0.83 to 0.60 cm), -0.15 cm (range, -2.58 to 1.18 cm), and -0.02 cm (range, -1.37 to 0.59 cm) in the X, Y, and Z directions, respectively. Large differences of over 1 cm were detected in 3 patients in the Y direction, while differences of more than 0.5 but less than 1 cm were observed in 5 patients in Y and Z directions. Median intra-fractional variation was 0.00 cm (range, -0.30 to 0.40 cm), -0.03 cm (range, -1.14 to 0.50 cm), 0.05 cm (range, -0.30 to 0.50 cm) in the X, Y, and Z directions, respectively. Significant intra-fractional variation of over 1 cm was observed in 2 patients in Y direction. Conclusion: Gated setup images provided a clear image quality for the detection of organ motion without a motion artifact. Significant intra- and inter-fractional variation and tidal amplitude differences between 4DCT and gated setup images were detected in some patients during the radiation treatment period, and therefore, should be considered when setting up the target margin. Monitoring of positional uncertainty and its adaptive feedback system can enhance the accuracy of treatments.

A Study on Nursing Service of Chronic Diseases by the First Step and Third Step Medical Treatment (1차 및 3차 진료기관 이용 만성질환자의 간호서비스에 관한 연구)

  • Cho Chong Sook
    • Journal of Korean Public Health Nursing
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    • v.10 no.2
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    • pp.103-118
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    • 1996
  • It is to be growing up the interest of community health affairs through visiting nursing care. The health medical treatment of Korea has been changed largely on the period. The juvenile population has decreased. This means that is has took the population consensus of advanced national organization to be increased by the old age. The transition of disease has changed from the contagious disease importance to the chronicity disease omportance because the domestic district population has experienced the sudden urbanization circumstance district population has experienced the sudden urbanization circumstance to be growing up $70\%$ of the whole population. When the nursing service has common function to be delivering from all direction to home, this study is getting the great important phase velocity in order to manage the kernel questional adult chronicity disease of health medical institution at the present age. (1) community over system or with people particularity (2) the first of third step medical treatments. The variety of medical treatments organization has quantity of the delivery manpower and specially between consumers and rdlated person. A qualitative difference is showed at the purpose to be seizing. That research related person is use at district health center in Seoul, by foundation on nurse registration book of H collage hospital and public health registration book. According the chronicity disease. age. and sex. nature agree-able standard 54 people took the content analysis on nurse registration book of total 108 people. The results of the study were as follows: 1. General background factors are houses or kind of medical facilities and number of patients in family. The first medical treatment is more patients than third medical treatment organization. The first medical treatment of economic environment os appering to be worse. 2. The chronicity disease frequency have been different speciality according to medical treatment organization. On case of the first medical treatment. Diabetes and High Blood Pressure were good but Cerebrum Vascular Accident(CVA) showed many for bed case. In addition. the number of family is comparative large exception of CVA on according for moving condition and health more than the first medical treatment. However. family condition. whole family percentage is decreasing preferably through the potential resource is increasing by the number of and the construction of family. The ability of real resource is considered to be low. 3. The average percentage of nurse service has appered to be differed two groups by the first step medical treatment(33.72 times) and third step medical treatment(45.70 times). However, the difference (the first step medical treatment and third step medical treatment) is to be limited to issue the medicine at the service. The condition of nurse care was the indirect nursing care. Supportiong area was to be related to volunteer service and administration support. 4. The various nursing care average percentage of the chronicity disease was increased by orders of Diabetes. High Blood Pressure. and CVA in examination result and the medical treatment. The indirect nursing care was also same. At third step medical treatment, orders of chronicity disease were same. The case of other area on service conditions were increased by order of Diabetes. High Blood Pressure, and CVA. However. it is never appearing the difference at bottleneck affairs nursing care. 5. When the visiting nursing care demand particularly. the average percentage of nursing care from the first step medical treatment that the time under a person is many more than the time over two people. However, there was no difference in statistic. Third step medical treatment is $49.81\%$ at the time under a person. The average nursing care service is appeared by more many when the visiting nursing care demand is a few by 12.83 at the time over two people. 6. By visiting nursing care percentage to be frequency that nursing care averaghe percentage and inter-relation are large. The related factor of the first medical treatment is 0.96. However, the related factor of third medical treatment has shown the decreased 0.49 for the condition of relation more than that. Therefore. the nursing care average percentage is related to the visiting times of a nurse. This result is be showing the obvious fact that the first step medical treatment is few more than third step medical treatment.

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A 0.31pJ/conv-step 13b 100MS/s 0.13um CMOS ADC for 3G Communication Systems (3G 통신 시스템 응용을 위한 0.31pJ/conv-step의 13비트 100MS/s 0.13um CMOS A/D 변환기)

  • Lee, Dong-Suk;Lee, Myung-Hwan;Kwon, Yi-Gi;Lee, Seung-Hoon
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.46 no.3
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    • pp.75-85
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    • 2009
  • This work proposes a 13b 100MS/s 0.13um CMOS ADC for 3G communication systems such as two-carrier W-CDMA applications simultaneously requiring high resolution, low power, and small size at high speed. The proposed ADC employs a four-step pipeline architecture to optimize power consumption and chip area at the target resolution and sampling rate. Area-efficient high-speed high-resolution gate-bootstrapping circuits are implemented at the sampling switches of the input SHA to maintain signal linearity over the Nyquist rate even at a 1.0V supply operation. The cascode compensation technique on a low-impedance path implemented in the two-stage amplifiers of the SHA and MDAC simultaneously achieves the required operation speed and phase margin with more reduced power consumption than the Miller compensation technique. Low-glitch dynamic latches in sub-ranging flash ADCs reduce kickback-noise referred to the differential input stage of the comparator by isolating the input stage from output nodes to improve system accuracy. The proposed low-noise current and voltage references based on triple negative T.C. circuits are employed on chip with optional off-chip reference voltages. The prototype ADC in a 0.13um 1P8M CMOS technology demonstrates the measured DNL and INL within 0.70LSB and 1.79LSB, respectively. The ADC shows a maximum SNDR of 64.5dB and a maximum SFDR of 78.0dB at 100MS/s, respectively. The ABC with an active die area of $1.22mm^2$ consumes 42.0mW at 100MS/s and a 1.2V supply, corresponding to a FOM of 0.31pJ/conv-step.

Development of validated Nursing Interventions for Home Health Care to Women who have had a Caesarian Delivery (조기퇴원 제왕절개 산욕부를 위한 가정간호 표준서 개발)

  • HwangBo, Su-Ja
    • Journal of Korean Academy of Nursing Administration
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    • v.6 no.1
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    • pp.135-146
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    • 2000
  • The purpose of this study was to develope, based on the Nursing Intervention Classification (NIC) system. a set of standardized nursing interventions which had been validated. and their associated activities. for use with nursing diagnoses related to home health care for women who have had a caesarian delivery and for their newborn babies. This descriptive study for instrument development had three phases: first. selection of nursing diagnoses. second, validation of the preliminary home health care interventions. and third, application of the home care interventions. In the first phases, diagnoses from 30 nursing records of clients of the home health care agency at P. medical center who were seen between April 21 and July 30. 1998. and from 5 textbooks were examined. Ten nursing diagnoses were selected through a comparison with the NANDA (North American Nursing Diagnosis Association) classification In the second phase. using the selected diagnoses. the nursing interventions were defined from the diagnoses-intervention linkage lists along with associated activities for each intervention list in NIC. To develope the preliminary interventions five-rounds of expertise tests were done. During the first four rounds. 5 experts in clinical nursing participated. and for the final content validity test of the preliminary interventions. 13 experts participated using the Fehring's Delphi technique. The expert group evaluated and defined the set of preliminary nursing interventions. In the third phases, clinical tests were held at in a home health care setting with two home health care nurses using the preliminary intervention list as a questionnaire. Thirty clients referred to the home health care agency at P. medical center between October 1998 and March 1999 were the subjects for this phase. Each of the activities were tested using dichotomous question method. The results of the study are as follows: 1. For the ten nursing diagnoses. 63 appropriate interventions were selected from 369 diagnoses interventions links in NlC., and from 1.465 associated nursing activities. From the 63 interventions. the nurses expert group developed 18 interventions and 258 activities as the preliminary intervention list through a five-round validity test 2. For the fifth content validity test using Fehring's model for determining lCV (Intervention Content Validity), a five point Likert scale was used with values converted to weights as follows: 1=0.0. 2=0.25. 3=0.50. 4=0.75. 5=1.0. Activities of less than O.50 were to be deleted. The range of ICV scores for the nursing diagnoses was 0.95-0.66. for the nursing interventions. 0.98-0.77 and for the nursing activities, 0.95-0.85. By Fehring's method. all of these were included in the preliminary intervention list. 3. Using a questionnaire format for the preliminary intervention list. clinical application tests were done. To define nursing diagnoses. home health care nurses applied each nursing diagnoses to every client. and it was found that 13 were most frequently used of 400 times diagnoses were used. Therefore. 13 nursing diagnoses were defined as validated nursing diagnoses. Ten were the same as from the nursing records and textbooks and three were new from the clinical application. The final list included 'Anxiety', 'Aspiration. risk for'. 'Infant behavior, potential for enhanced, organized'. 'Infant feeding pattern. ineffective'. 'Infection'. 'Knowledge deficit'. 'Nutrition, less than body requirements. altered', 'Pain'. 'Parenting'. 'Skin integrity. risk for. impared' and 'Risk for activity intolerance'. 'Self-esteem disturbance', 'Sleep pattern disturbance' 4. In all. there were 19 interventions. 18 preliminary nursing interventions and one more intervention added from the clinical setting. 'Body image enhancement'. For 265 associated nursing activities. clinical application tests were also done. The intervention rate of 19 interventions was from 81.6% to 100%, so all 19 interventions were in c1uded in the validated intervention set. From the 265 nursing activities. 261(98.5%) were accepted and four activities were deleted. those with an implimentation rate of less than 50%. 5. In conclusion. 13 diagnoses. 19 interventions and 261 activities were validated for the final validated nursing intervention set.

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($P16^{ink4}$ Methylation in Squamous Cell Carcinoma of the Oral Cavity. (구강 편평세포암종에서 $P16^{ink4}$ 유전자의 Methylation에 대한 연구)

  • Kang, Gin-Won;Kim, Kyung-Wook;Lyu, Jin-Woo;Kim, Chang-Jin
    • Maxillofacial Plastic and Reconstructive Surgery
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    • v.22 no.2
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    • pp.164-173
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    • 2000
  • The p16 protein is a cyclin dependent kinase inhibitor that inhibits cell cycle progression from $G_1$ phase to S phase in cell cycle. Many p16 gene mutations have been noted in many cancer-cell lines and in some primary cancers, and alterations of p16 gene function by DNA methylation have been noticed in various kinds of cancer tissues and cell-lines. There have been a large body of literature has accumulated indicating that abnormal patterns of DNA methylation (both hypomethylation and hypermethylation) occur in a wide variety of human neoplasma and that these aberrations of DNA methylation may play an important epigenetic role in the development and progression of neoplasia. DNA methylation is a part of the inheritable epigenetic system that influences expression or silencing of genes necessary for normal differentiation and proliferation. Gene activity may be silenced by methylation of up steream regulatory regions. Reactivation is associated with demethylation. Although evidence or a high incidence of p16 alterations in a variety of cell lines and primary tumors has been reported, that has been contested by other investigators. The precise mechanisms by which abnormal methylation might contribute to carcinogenesis are still not fully elucidated, but conceivably could involve the modulation of oncogene and other important regulatory gene expression, in addition to creating areas of genetic instability, thus predisposing to mutational events causing neoplasia. There have been many variable results of studies of head and neck squamous cell carcinoma(HNSCC). This investigation was studied on 13 primary HNSCC for p16 gene status by protein expression in immunohistochemistry, and DNA genetic/epigenetic analyzed to determine the incidence, the mechanisms, and the potential biological significance of its Inactivation. As methylation detection method of p16 gene, the methylation specific PCR(MSP) is sensitive and specific for methylation of any block of CpG sites in a CpG islands using bisulfite-modified DNA. The genomic DNA is modified by treatment with sodium bisulfate, which converts all unmethylated cytosines to uracil(thymidine). The primers designed for MSP were chosen for regions containing frequent cytosines (to distinguish unmodified from modified DNA), and CpG pairs near the 5' end of the primers (to provide maximal discrimination in the PCR between methylated and unmethylated DNA). The two strands of DNA are no longer complementary after bisulfite treatment, primers can be designed for either modified strand. In this study, 13 paraffin embedded block tissues were used, so the fragment of DNA to be amplified was intentionally small, to allow the assessment of methylation pattern in a limited region and to facilitate the application of this technique to samlples. In this 13 primary HNSCC tissues, there was no methylation of p16 promoter gene (detected by MSP and automatic sequencing). The p16 protein-specific immunohistochemical staining was performed on 13 paraffin embedded primary HNSCC tissue samples. Twelve cases among the 13 showed altered expression of p16 proteins (negative expression). In this study, The author suggested that low expression of p16 protein may play an important role in human HNSCC, and this study suggested that many kinds of genetic mechanisms including DNA methylation may play the role in carcinogenesis.

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Agricultural Policies and Geographical Specialization of Farming in England (영국의 농업정책이 지리적 전문화에 미친 영향 연구)

  • Kim, Ki-Hyuk
    • Journal of the Korean association of regional geographers
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    • v.5 no.1
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    • pp.101-120
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    • 1999
  • The purpose of this study is to analyze the impact of agricultural polices on the change of regional structure based on the specialization during the productivism period. Analysis are carried on through the comparison of distribution in 1950s and 1997. Since the 1950s, governmental policy has played a leading role in shaping the pattern of farming in Great Britain. The range of British measures have also been employed in an attempt to improve the efficiency of agriculture and raise farm income. Three fairly distinct phase can be identified in the developing relationship between government policies and British agriculture in the postwar period. In the 1st phase, The Agricultural Act of 1947 laid the foundations for agricultural productivism in Great Britain until membership of the EC. This was to be achieved through the system of price support and guaranteed prices and the means of a series of grants and subsidies. Guaranteed prices encouraged farmenrs to intensify production and specialize in either cereal farming or milk-beef enterprise. The former favoured eastern areas, whereas the latter favoured western areas. Various grants and subsidies were made available to farmers during this period, again as a way of increasing efficiency and farm incomes. Many policies, such as Calf Subsidy and the Ploughing Grant, Hill cow and Hill Sheep Schemes and the Hill Farming and Livestock Rearing Grant was provided. Some of these policies favoured western uplands, whilst the others was biased towards the Lake District. Concentration of farms occured especially in near the London Metropolitan Area and south part of Scotland. In the 2nd stage after the membership of EC, very high guaranteed price created a relatively risk-free environment, so farmers intensified production and levels of self-sufficiency for most agriculture risen considerably. As farmers were being paid high prices for as much as they could produce, the policy favoured areas of larger-scale farming in eastern Britain. As a result of increasing regional disparities in agriculture, the CAP became more geographically sensitive in 1975 with the setting up of the Less Favoured Areas(LFAs). But they are biased towards the larger farms, because such farms have more crops and/or livestock, but small farms with low incomes are in most need of support. Specialization of cereals such wheat and barely was occured, but these two cereal crops have experienced rather different trend since 1950s. Under the CAP, farmers have been paid higher guaranteed prices for wheat than for barely because of the relative shortage of wheat in the EC. And more barely were cultivated as feedstuffs for livestock by home-grown cereals. In the 1950s dairying was already declining in what was to become the arable areas of southern and eastern England. By the mid-1980s, the pastral core had maintained its dominance, but the pastoral periphery had easily surpassed arable England as the second most important dairying district. Pig farming had become increasingly concentrated in intensive units in the main cereal areas of eastern England. These results show that the measure of agricultural policy induced the concentration and specialization implicitly. Measures for increasing demand, reducing supply or raising farm incomes are favoured by large scale farming. And price support induced specialization of farming. And technology for specialization are diffused and induced geographical specialization. This is the process of change of regional structure through the specialization.

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Effect of Freeze-Dried Korean-Style Dishes on Visceral Fats and Serum Lipid Concentrations in Rats Fed with High Fat Diet (한식첨가식(添加食)이 고지방식(高脂肪食)을 급여한 흰쥐의 내장지방과 혈청 지질농도에 미치는 영향)

  • Hong, Sang-Pil;Han, Chan-Kyu;Lee, Min-A;Yang, Ji-Na;Shin, Dong-Bum
    • Journal of the Korean Society of Food Culture
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    • v.23 no.1
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    • pp.90-96
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    • 2008
  • This study was performed to reveal nutritional excellency of popular Korean dishes, which were intended to distribute as a take-out type food suited for Americans. Four Korean dishes were selected due to their high preference from American sensory panels: Jeyuk-bokkeum (B), Kimchi-bokkeum (C), Dubu-jorim (D) and Namul (E). Nine weeks of the experimental periods were composed of two parts. In phase 1(5 weeks of the first half), high fat diets were fed to all treatments including the control group (A). In phase 2 (4 weeks of the last half), freeze-dried four Korean dishes were fed to the treatments except for the control. There was no significant difference in the final body weights among the groups as well as daily body weight gains and FER. Organ weights of the control group tended to be smaller than those of the treatment groups. For visceral fats, perirenal fat pad (RFP) and epidydimal fat pad (EFP) of the groups C and D were decreased by 20% compared with those of the group A. Total cholesterol level of the group C (94.13 mg/dL) was significantly lower than any other groups (p<0.05), but there was no significant difference in triglyceride(TG) level. HDL-cholesterol level of group B(20.38 mg/dL) was significantly higher than that of group D (17.25 mg/dL), but no significant differences were seen in groups C and E (p<0.05). In LDL-cholesterol level, the highest level was seen in group D, the lowest level in group E (p<0.05). From the findings, Kimchi-bokkeum, Dubu-jorim and Namul were superior to those of the control and jeyukbokkeum in terms of the blood lipid profiles. It might be a good Korean style take-out items suited for the Americans’ taste along with a good nutritional quality in the near future.

Psychophysiological Characteristics of Insomnia Patients Measured by Biofeedback System (바이오피드백을 이용하여 측정한 불면증 환자의 정신생리적 특징)

  • Huh, Sung-Young;Lee, Jin-Seong;Kim, Sung-Gon;Kim, Ji-Hoon;Jung, Woo-Young
    • Sleep Medicine and Psychophysiology
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    • v.22 no.2
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    • pp.70-76
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    • 2015
  • Background and Objectives: Insomnia is the most prevalent sleep disorder in the general population and is considered to be a disorder of hyperarousal. The aim of this study was to measure the psychophysiological responses in insomnia patients using a biofeedback system, and to compare them with results from normal healthy subjects. Materials and Methods: Eighty patients with primary insomnia (35 males and 45 females, average age $49.71{\pm}12.91years$) and 101 normal healthy controls (64 males and 37 females, average age $27.65{\pm}2.77$) participated in this study. Electromyography (EMG), heart rate (HR), skin conductance (SC), skin temperature (ST), and respiratory rate (RR) were recorded using a biofeedback system during 5 phases (baseline, stress 1, recovery 1, stress 2, recovery 2) of a stress reactivity test, and average values were calculated. Difference in values between the two groups in each corresponding phase was analyzed with independent t-test, and change in values across phases of the stress reactivity test was analyzed with paired t-test (all two-tailed, p<0.05). Results: Compared to normal controls, insomnia patients had higher EMG in all 5 phases (baseline : $7.72{\pm}3.88{\mu}V$ vs. $4.89{\pm}1.73{\mu}V$, t = -6.06, p<0.001 ; stress 1 : $10.29{\pm}5.16{\mu}V$ vs. $6.63{\pm}2.48{\mu}V$, t = -5.84, p<0.001 ; recovery 1 : $7.87{\pm}3.86{\mu}V$ vs. $5.17{\pm}2.17{\mu}V$, t = -5.61, p<0.001 ; stress 2 : $10.22{\pm}6.07{\mu}V$ vs. $6.98{\pm}2.98{\mu}V$, t = -4.37, p<0.001 ; recovery 2 : $7.88{\pm}4.25{\mu}V$ vs. $5.17{\pm}1.99{\mu}V$, t = -5.27, p<0.001). Change in heart rate across phases of the stress reactivity test were higher in normal controls than in insomnia patients (stress 1-baseline : $6.48{\pm}0.59$ vs. $3.77{\pm}0.59$, t = 3.22, p = 0.002 ; recovery 1- stress 1 : $-5.36{\pm}0.0.59$ vs. $-3.16{\pm}0.47$, t = 2.91, p = 0.004 ; stress 2-recovery 1 : $8.45{\pm}0.61$ vs. $4.03{\pm}0.47$, t = 5.72, p<0.001 ; recovery 2-stress 2 : $-8.56{\pm}0.65$ vs. $4.02{\pm}0.51$, t = -5.31, p<0.001). Conclusion: Psychophysiological profiles of insomnia patients in a stress reactivity test were different from those of normal healthy controls. These results suggest that the sympathetic nervous system is more highly activated in insomnia patients.

Continuous Process for the Etching, Rinsing and Drying of MEMS Using Supercritical Carbon Dioxide (초임계 이산화탄소를 이용한 미세전자기계시스템의 식각, 세정, 건조 연속 공정)

  • Min, Seon Ki;Han, Gap Su;You, Seong-sik
    • Korean Chemical Engineering Research
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    • v.53 no.5
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    • pp.557-564
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    • 2015
  • The previous etching, rinsing and drying processes of wafers for MEMS (microelectromechanical system) using SC-$CO_2$ (supercritical-$CO_2$) consists of two steps. Firstly, MEMS-wafers are etched by organic solvent in a separate etching equipment from the high pressure dryer and then moved to the high pressure dryer to rinse and dry them using SC-$CO_2$. We found that the previous two step process could be applied to etch and dry wafers for MEMS but could not confirm the reproducibility through several experiments. We thought the cause of that was the stiction of structures occurring due to vaporization of the etching solvent during moving MEMS wafer to high pressure dryer after etching it outside. In order to improve the structure stiction problem, we designed a continuous process for etching, rinsing and drying MEMS-wafers using SC-$CO_2$ without moving them. And we also wanted to know relations of states of carbon dioxide (gas, liquid, supercritical fluid) to the structure stiction problem. In the case of using gas carbon dioxide (3 MPa, $25^{\circ}C$) as an etching solvent, we could obtain well-treated MEMS-wafers without stiction and confirm the reproducibility of experimental results. The quantity of rinsing solvent used could be also reduced compared with the previous technology. In the case of using liquid carbon dioxide (3 MPa, $5^{\circ}C$, we could not obtain well-treated MEMS-wafers without stiction due to the phase separation of between liquid carbon dioxide and etching co-solvent(acetone). In the case of using SC-$CO_2$ (7.5 Mpa, $40^{\circ}C$), we had as good results as those of the case using gas-$CO_2$. Besides the processing time was shortened compared with that of the case of using gas-$CO_2$.

Study of Surfactant Enhanced Remediation Methods for Organic Pollutant(NAPL) Distributed over the Heterogeneous Medium (계면활성제를 이용한 불균질 매질에서 유기오염물(NAPL)의 정화효율에 관한 실험)

  • 서형기;이민희;정상용
    • Journal of Soil and Groundwater Environment
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    • v.6 no.4
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    • pp.51-59
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    • 2001
  • Column and box tests were performed to investigate the removal efficiency of NAPL using the surfactant enhanced flushing In heterogeneous medium. Homogeneous Ottawa sand and heterogeneous soil were used to verify the increase of remediation efficiency for the surfactant enhanced flushing in column test. Box tests with two different heterogeneous sub-structure were performed to quantify the capability of the surfactant enhanced flushing as a remediation method to remove NAPL from the heterogeneous medium. Two different grain size sand layers were repeated in the box to simulate the heterogeneous layer formation and the modified fault structure was built to simulate the fault system in the box. O-xylene as a LNAPL and PCE as a DNAPL were used and oleamide as a non-ionic surfactant. The maximum NAPL effluent concentration with 1% oleamide flushing in the homogeneous column test increased about 460 times compared to that with only water flushing and about 250 times increased in the real soil column test. In heterogeneous medium, the maximum effluent concentration increased about 150 times in 1% oleamide flushing and most of NAPL were removed from the box within 8 pore volume flushing, suggesting that the removal efficiency increased very much compared to in only water flushing. Results investigated the capability of the surfactant enhanced remediation method to remove NAPL even in heterogeneous medium.

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