• 자원리싸이클링
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• 제13권2호
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• pp.9-15
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• 2004

석유화학공정으로부터 폐기되는 폐산화철촉매를 이용하여 도금합성폐수중 크롬회수에 관한 연구를 회분식과 연속식으로 실시하였다. 도금합성제수 중 $CrO _{4}^{-2}$ 형태의 음이온으로 존재하는 6가 크롬은 폐산화철촉매의 등전점(pH 3.0)이하에서 폐촉매와 물리적 흡착을 한다. 한편, 6가 크롬은 pH 3.0 이상에서도 폐촉매의 수산화철과 산화환원반응에 의해 일부 환원되어 $Cr(OH)_3$로 침전한다. 컬럼을 이용한 크롬 연속회수실험에서 크롬합성폐수의 pH가 0.5∼2.0일 때 폐촉매의 크롬흡착량은 2.0∼2.3g/L이며, pH가 3.0에서는 1.5g/L이었다. 폐수 중 크롬농도가 50∼500mg/L로 높아질수록 폐촉매에 흡착한 크롬누적량은 1.29∼8.56g/L로 증가하지만, 유속이 30∼80 ml/mm으로 증가하여도 크롬 흡착누적량은 2.21∼2.49 mg/L로 거의 유사하였다.

• 대한수학회지
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• 제56권3호
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• pp.689-701
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• 2019

We study the recovery results of ${\ell}_p$-constrained compressive sensing (CS) with $p{\geq}1$ via robust width property and determine conditions on the number of measurements for standard Gaussian matrices under which the property holds with high probability. Our paper extends the existing results in Cahill and Mixon from ${\ell}_2$-constrained CS to ${\ell}_p$-constrained case with $p{\geq}1$ and complements the recovery analysis for robust CS with ${\ell}_p$ loss function.

• Korean Journal of Radiology
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• 제22권7호
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• pp.1163-1171
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• 2021

Objective: To analyze the correlations between intraoperative ultrasound and MRI metrics of the spinal cord in degenerative cervical myelopathy and identify novel potential predictive ultrasonic indicators of neurological recovery for degenerative cervical myelopathy. Materials and Methods: Twenty-two patients who underwent French-door laminoplasty for multilevel degenerative cervical myelopathy were followed up for 12 months. The Japanese Orthopedic Association (JOA) scores were assessed preoperatively and 12 months postoperatively. Maximum spinal cord compression and compression rates were measured and calculated using both intraoperative ultrasound imaging and preoperative T2-weight (T2W) MRI. Signal change rates of the spinal cord on preoperative T2W MRI and gray value ratios of dorsal and ventral spinal cord hyperechogenicity on intraoperative ultrasound imaging were measured and calculated. Correlations between intraoperative ultrasound metrics, MRI metrics, and the recovery rate JOA scores were analyzed using Spearman correlation analysis. Results: The postoperative JOA scores improved significantly, with a mean recovery rate of 65.0 ± 20.3% (p < 0.001). No significant correlations were found between the operative ultrasound metrics and MRI metrics. The gray value ratios of the spinal cord hyperechogenicity was negatively correlated with the recovery rate of JOA scores (ρ = -0.638, p = 0.001), while the ventral and dorsal gray value ratios of spinal cord hyperechogenicity were negatively correlated with the recovery rate of JOA-motor scores (ρ = -0.582, p = 0.004) and JOA-sensory scores (ρ = -0.452, p = 0.035), respectively. The dorsal gray value ratio was significantly higher than the ventral gray value ratio (p < 0.001), while the recovery rate of JOA-motor scores was better than that of JOA-sensory scores at 12 months post-surgery (p = 0.028). Conclusion: For degenerative cervical myelopathy, the correlations between intraoperative ultrasound and preoperative T2W MRI metrics were not significant. Gray value ratios of the spinal cord hyperechogenicity and dorsal and ventral spinal cord hyperechogenicity were significantly correlated with neurological recovery at 12 months postoperatively.

• 치위생과학회지
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• 제6권4호
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• pp.231-235
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• 2006

본 연구는 부가중합형실리콘인상재의 정밀 인상채득에 영향을 미치는 요인, 압축변형률, 탄성회복률, 점주도와 젖음성을 평가하기 위하여 현재 시판되고 있는 4종류의 인상재 Examixfine(GC), Aquasilultra(Dentsply), Extrude(Kerr), Perfect-F(Handae)를 이용하여 실험하였다. 실험 데이터는 SPSSWIN 12.0을 사용하여 분석하였고, 결과는 다음과 같다. 1. 압축변형률은 Extrude가 4.86%로 가장 낮게 나타났고, Examixfine이 6.78%로 가장 크게 나타났다. Examixfine과 Perfect-F 사이에는 유의한 값의 차이가 없었으나, 다른 인상재 그룹에서는 유의성이 있었다. (p < 0.001). 2. Extrude의 탄성회복률이 99.83%로 가장 크게 나타났고, Perfect-F가 96.54%로 가장 낮게 나타났다. Examixfine과 Aquasilultra 간에는 유의성이 없었으나, 다른 인상재그룹간에는 유의한 차이가 있었다(p < 0.001). 3. 점주도의 측정결과에서 Examixfine이 점주도 값이 45.12mm로 가장 높았고, Perfect-F의 경우 40.28 mm로 가장 낮은 점주도 값을 나타내었다. Examixfine과 Aquasilultra, Extrude와 Perfect-F 간에는 유의한 차이가 나타나지 않았다(p > 0.001). 4. 젖음성에서는 Aquasilultra가 $47.85^{\circ}$로 가장 접촉각이 작게 나타나 친수성이 가장 우수하게 나타났고, Perfect-F는 접촉각이 $94.89^{\circ}$로 접촉각이 크게 나타나 소수성으로 나타났다. 인상재 종류별로도 각각 유의성이 존재하였다 (p < 0.001). 5. 접촉각은 압축변형률(p < 0.01), 탄성회복률(p < 0.01), 점주도(p < 0.05)와 상관관계가 있었고, 탄성회복률과 점주도 와는 음의 상관관계를 보였다. 압축변형률은 접촉각, 탄성회복률과 상관관계가 있었고(p < 0.01), 탄성회복률과 음의 상관관계를 나타냈다. 탄성회복률은 접촉각, 압축변형률과 음의 상관관계를 가지고 있었고(p < 0.01), 점주도도 접촉각과 음의 상관관계를 보였다(p < 0.05).

• 한국환경보건학회지
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• 제29권2호
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• pp.69-76
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• 2003

Hexavalent chromium may reduce on polyvinyl chloride (PVC) filter during sampling and storage of sample. Recently, new or modified filters for preventing Cr(VI) from the reduction has been introduced. Thus, this study was performed to compare the reduction behaviors of Cr(VI) on several sampling filters and to find the most appropriate filter for airborne Cr(VI) sampling in plating operation. The results were as follows. 1. There were statistically significant differences among PVC, polytetrafluoroethylene (PTFE). glass fiber (GF) and polyvinylidene fluoride (PVDF) filters in recovery rates of spiked Cr(VI) samples by storage time(p<0.05). There was no significant difference between PVC and PTFE filters(p>0.05). The PVC and PTFE filters showed higher recoveries than GF and PVDF filters(p<0.05). 2. The quartz fiber(QF) filter treated with an alkali solution(2% NaOH/3% Na$_2$CO$_3$, 1% NaOH) showed a significantly higher recovery of Cr(VI) by storage time than other filters(GF and QF filter)(p<0.05). There was no difference in recovery of Cr(VI) between alkali-treated and untreated GF it filters(p>0.05). But the QF filters treated with two alkali solution showed a significantly higher recovery than the untreated QF filter(p<0.05). There was no significant difference in recovery of Cr(VI) between QF filters treated with 1% NaOH and 2% NaOH/3% Na$_2$CO$_3$(p>0.05). In conclusion, treatment of QF fillers with alkali solution was most effective in protecting from the reduction of Cr(VI).

• 한국자원리싸이클링학회:학술대회논문집
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• 한국자원리싸이클링학회 2003년도 추계정기총회 및 국제심포지엄
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• pp.122-128
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• 2003

To develop a Mg-Zeolite for simultaneous recovery of the N and the P from sewage water, the natural zeolite was treated with 20% $MgCl_2$ solution by changing the pH the temperature and the treating time of the solution. And the contents of Ca Fe Na K Mg of Mg-Zeolite were analyzed by ICP. The optimum treatment condition for Mg-Zeolite was induced to pH 7.0 $50^{\circ}C$ in 20% $MgCl_2$ solution and for 80min treatment. And the Na and the K ions in natural zeolite are significant factors for Mg exchange in the zeolite.

• 대한물리치료과학회지
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• 제15권1호
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• pp.21-28
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• 2008

The purposes of this study are to quantify energy expenditure by measuring oxygen consumption while performing occupational therapy activities most commonly used for adult hemiplegia patients, to recommend a optimal dosage of exercise by comparing energy expenditure according to the recovery stage, and to suggest a precaution in the treatment of patients with cardiac disorders. According to Brunnstrom recovery stages in hand function, subjects were allocated to group I(3rd and 4th Brunnstrom recovery stages) and group II(5th and 6th Brunnstrom recovery stages). Outcome measures included oxygen consumption, energy expenditure rate, and heart rate during each activity and in recovery period after the activity. Occupational activities including sanding activity, putty activity, and skateboard activity were carried out for all patients. In sanding and putty activities, there were significant differences of oxygen consumption and energy expenditure during the activity between groupⅠandⅡ(p<0.05), but there were not significant differences of oxygen consumption, energy expenditure and heart rate in the recovery period(p>0.05). In skateboard activity, there were no significant differences in oxygen consumption, energy expenditure and heart rates between the two groups during the activity and in the recovery period(p>0.05). The findings indicates that cardiovascular demands for basic activities usually peformed for a treatment may be depended on the physical recovery of patients with hemiplegia. Therefore, therapeutic activities for patients should be selected with the great care.

• 한국환경과학회:학술대회논문집
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• 한국환경과학회 2019년도 정기학술대회 발표논문집
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• pp.134-134
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• 2019

Utilization of organic waste as a renewable energy source is promising for sustainability and mitigation of climate change. Pyrolysis converts organic waste to gas, oil, and biochar by incomplete biomass combustion. Biochar is widely used as a soil conditioner and adsorbent. Biochar adsorbs/desorbs metals and ions depending on the soil environment and condition to act as a nutrient buffer in soils. Biochar is also regarded as a carbon storage by fixation of organic carbon. Phosphorus (P) and nitrogen (N) are strictly controlled in many wastewater treatment plants because it causes eutrophication in water bodies. P and N is removed by biological and chemical methods in wastewater treatment plants and transferred to sludge for disposal. On the other hand, P is an irreplaceable essential element for all living organisms and its resource (phosphate rock) is estimated about 100 years of economical mining. Therefore, P and N recovery from waste and wastewater is a critical issue for sustainable human society. For the purpose, intensive researches have been carried out to remove and recover P and N from waste and wastewater. Previous studies have shown that biochars can adsorb and desorbed phosphates implying that biochars could be a complementary fertilizer. However, most of the conventional biochar have limited capacity to adsorb phosphates and nitrate. Recent studies have focused on biochar impregnated with metal salts to improve phosphates and nitrate adsorption by synthesizing biochars with novel structures and surface properties. Metal salts and metal oxides have been used for the surface modification of biochars. If P removal is the only concern, P adsorption kinetics and capacity are the only important factors. If both of P and N removal and the application of recovery are concerned, however, P and N desorption characteristics and bioavailability are also critical factors to be considered. Most of the researches on impregnated biochars have focused on P removal efficiency and kinetics. In this study, coffee waste is thermally treated to produce biochar and it was impregnated with Mg/Al to enhance phosphates and nitrate adsorption/desorption and P bioavailability to increase its value as a fertilizer. Kinetics of phosphates and nitrate adsorption/desorption and bioavailability analysis were carried out to estimate its potential as a P and N removal adsorbent in wasewater and a fertilizer in soil.

• 한국산학기술학회논문지
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• 제21권6호
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• pp.256-265
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• 2020

본 연구는 정신장애인 회복을 위한 당사자 리더십 프로그램을 개발하고 그 효과성을 탐색하는 것이 목적이다. 프로그램 개발을 위해 문헌검토와 선행프로그램 분석을 실시하였으며, 정신장애에 대한 이해-셀프리더십-역량강화-자기 주도 실천계획을 포함하는 Brown의 회복 프레임워크를 적용하였다. 이러한 과정을 통해 당사자주도 활동, 장애의 이해와 인식개선 활동, 당사자 실천계획개발 등을 주제로 2박 3일 동안 총 6회기 프로그램을 개발하였다. 본 프로그램은 회복의 가치를 기반으로 당사자 스스로 할 수 있다는 역량강화를 위해 교육-이해-계획-실행의 단계로 구성하였다. 개발된 프로그램은 정신재활시설 이용자 20명을 대상으로 실시하였다. 프로그램 참여 후 변화를 측정하기 위해 낙인, 역량강화, 셀프리더십, 장애수용 척도를 이용하여 비교분석하였다. 분석결과 참여자들의 낙인(p < .05), 역량강화(p < .05), 셀프리더십(p < .01), 장애수용(p < .05)에서 통계적으로 유의미한 변화가 있는 것으로 나타났다. 이러한 결과는 개발된 당사자 리더십 프로그램이 정신장애에 대한 이해 증가, 역량강화, 리더십 능력향상을 포함하는 회복 프로그램임을 시사한다. 연구결과를 기반으로 향후 당사자 리더십 프로그램의 확대를 위한 논의와 제언을 하였다.

• 한국응용과학기술학회지
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• 제27권2호
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• pp.208-215
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• 2010

EAF dust which is contained around 30% of zinc, 15% of iron and 3% of lead individually, is chemically treated by ammonium chloride, ammonia water, ammonia gas and carbon dioxide, and also tested and identified the ratios of the recovery of In by applied the variations of particle size, pH and heating temperature as well, in order to getting optimized recovery of the In metal after performing all of those processes. Experimental results showed that the rate of Zn recovery is 97% when the mixture of 1.3 of $NH_4Cl$/EAF is heated to the temperature of $400^{\circ}C$ and leached by water, and 95% recovery of In when ammonia gas and carbon dioxide is added simultaneously and adjust the 9.5 of pH to the same mixture above. For the purpose of remove the impurities in the mixed sample, which is prepared by the two samples, indicated above showing as the ratio of 95% and 97% recovery, in case of applied the cementation process to it, and also by electrolytic process, produced the In plate of 95~97%, and acquired 99-99.5% of In metal ingot finally by applied the heating process at $470{\sim}500^{\circ}C$.