흡수에서 합성수지 충전물(Nor-Pac, 25mm)로부터 분리작용의 연구

김장호,김재홍,김종수,김형호 동아대학교 환경문제연구소 2002 硏究報告 Vol.25 No.1

This study was carried out to demonstrate the superiority of used packing in view of energy saving and efficiency of mass transfer, comparing with conventional packing. The results are as follows 1. Owing to low pressure drop under high load, 25mm NSW-ring, pp. can cause energy saving. 2. The unique magnitudes of used packing are as follows : C_(G) = 5.78 m = 0.67 n = 0.46 3. Used packing can make high efficiency including energy saving because of low pressure drop per the number of transfer unit. To rate the characteristic of packing, it should be carried out that the measurement of pressure drop per packing height and per the number of transfer unit. This study demonstrated the superiority of used packing by caning out above experiment and could be used as basic reference for design and predicting efficiency of packing tower which is filled with same packing.

생체분해성 망막압정을 이용한 망막고정에 대한 실험적 연구

김용백,민병무,김창식,박근성,김승영,길숙종,조항진,이성복,노승무,송규상,강대영,조준식,양준묵,정경수,최선웅,이진호,김학용,인현빈 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

Biodegradable retinal fixation devices obtain mechnical fixation of the retina with desirable chorioretinal scarring and with the potential for local, sustained release of antimetabolites and steroids to inhibit proliferative vitreoretinopathy. We manufactured a biodegradable retinal tack with barb that was designed in order to prevent intrusion from implantation of retinal tacks. This study was carried to evaluate the efficacy for retinal fixation and the capability for sustained release of drugs with a newly designed biodegradable retinal tack Biodegradable retinal tacks were made of polymers of glycolic acids and were designed with barbs in a shape to prevent the disinsertion. Biodegradale retinal tacks are divided into 3 parts, a conical portion that is inserted into the sclera, a cylinder portion that remains in the vitreous, and a neck portion between the pin and the cylinder. The tapered conical end was manufactured to allow easy insertion through the retina and choroid into the sclera. A cylinder portion was manufactured with a tapered angle that fixes firmly into the orifice of 19 gauge spinal needle. A neck portion, 0.4 mm in diameter, was designed to prevent disinsertion from following implantation of retinal tack. The applicator was a 19 gauge spinal needle and its orifice was prepared to 15°angle to accept the tapered cylinder portion of the retinal tack. The retinal tacks, secured in the needles, were passed through the formed vitreous and inserted into the retina, choroid, and sclera and were released by pushing the internal needle, usually within 2-3mm of the medullary ray of the posterior rabbit retina A retinal tack was placed in each of 8 pigmented rabbit eyes. Slit-lamp biomicroscopy, indirect ophthalmoscopy and fundus photography were performed periodically from 1 day to 8 weeks after surgery. Eight eyes were enucleated and studied by light microscopy at 8 weeks. Biomicroscopic evaluation of the animals revealed edemas adjacent to the retinal surfaces immediately after insertion of the biodegradable retinal tacks in all the animals. These edemas disappeared after 1 week. The first noticeable change in the size of retinal tacks was shown after 2weeks. The size of the retinal tacks gradually got smaller, decreasing to about one-half at 4 weeks and about one-third at 8 weeks. All retinal tacks remained in inserted places without any movement for an 8 week period. On light microscopy, epiretinal proliferations were seen to extend into the vitreous cavity. Cellular capsules that lined the inner aspect of the scleral defect caused by tack insertion were found. However the adjacent retina had a normal cytologic appearance and architecture in all specimens. We manufactured a biodegradable retinal tack that is designed to prevent intrusion from implantation of retinal tacks. All biodegradable retinal tacks reduce in size with time, but no retinal tacks extruded from the inserted place. The newly designed biodegradable retinal tack can be used for retinal fixation and may be used as a vehicle for the introduction of pharmacologic agents to prevent the cellular events that promote proliferative vitreoretinopathy.

Nylon 6 fiber media를 이용한 Biofilter의 VOCs(Toluene)의 제거

김장호,최동훈,김종수,김형호,장봉수 동아대학교 환경문제연구소 2002 硏究報告 Vol.25 No.1

This study was investigated the application and kinetics of biofiltration using cometabolic process to remediate gaseous toluene that are highly recalcitrant to adsoption and biodegradation. Biofiltration was successfully applied to treat amixture of volatile organic compounds(Toluene) from contaminated air stream. Immobilized Ps.oleovorans biofilter was evaluated for its value in simultaneous removal of Toluene from waste air stream. In the loading rate (1,000ppm) and space velocity(1,200hr). the average removal efficiencies of Toluene were 33.7%. and CO2 production rate were 5.28㎎/hr

우리나라 지역 직업성질환 감시체계의 현황과 전망

임종한,장성실,김성아,문재동,채창호,홍윤철,김수영,김진석,김영욱,한상환,이혜숙,원종욱,송동빈,하은희,강성규 대한산업의학회 2001 대한직업환경의학회지 Vol.13 No.2

기존의 특수건강진단과 작업환경측정을 통한 직업병 관리가 진폐증, 소음성난청 등의 소수 특정질환에 국한되고 실제 직업병 발생 규모 파악이나 신종 직업병의 발견에 한계를 보인다는 사실은 산업의학전문가들 사이에서도 공감을 이루고 있다. 미국과 영국 등에서의 직업성질환 감시체계에 대한 경험은 우리 나라의 직업성질환 감시체계 구축에도 새로운 자극제가 되면서, 1998년이후 인천, 대전, 여천, 구미, 부울경 지역에서 지역 직업성질환감시체계를 산업보건관리의 중요한 시스템으로 구축하려는 노력이 확산되고 있다. 새로이 구축되어지는 이들 지역 직업성질환 감시체계는 감시하고자 하는 대상질환, 활용 가능한 인적자원 및 자료원, 지역 의료체계의 특수성 등에 따라서 목적과 방법을 달리하면서 독특한 형태로 발전을 하고 있다. 각 지역단위 감시체계들이 그 상황에 맞게 독특한 목적과 전략들을 발전 시키면서도, 향후 발전할 국가적인 차원의 직업성질환 감시체계 구축을 위하여 직업성질환 감시의 기본 전략 등을 공유하는 등의 노력이 필요하다. 환례 정의 및 기본적인 등록 서식의 공유, 직업성질환 감시 자료원의 발굴, 공동의 정보 네트워크 및 직업성질환 감시 데이터베이스 구축 등 직업성질환 감시활동을 지원하기 위한 여러 기초 인프라 구축에 힘을 모아야 할 것이다. 우리 나라에서 직업성질환 감시체계를 성공적으로 구축하기 위해서는 수집된 자료의 질 관리를 위한 직업성질환 감시의 원칙 제정과 감시 전략의 공유 등이 필요하며, 전국적인 직업성질환 감시체계의 하부구조라고 할 수 있는 지역감시체계의 기초 토대 마련과 강화작업이 절실하게 필요하다.

생체분해성 고분자를 이용한 사시수술용 제형개발 및 효용성에 대한 연구

민병무,김용백,김승영,김창식,박근성,길숙종,조항진,이성복,노승무,송규상,강대영,조준식,양준묵,정경수,최선웅,이진호,김학용,인현빈 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

A new device, muscle clamping system was developed to facilitate exact quatifying technique A strabismus surgery, and reduce the risk of complications. The device is composed of a lower fixing body with three jaws and an upper supporting body. They are used to clip an extraocular muscle and fix it to the sclera with a single bite. Superior rectus recession on 16 rabbit eyes were performed with this new device. Conjunctival injection, muscle adhesion strength, and light microscopic findings were examined at 1, 2, 4 and 8 weeks postoperatively. The Conjunctival injection were minimal, adhesion power ranged from 420 to 600 gram gravity, which is sufficient in withstand the normal pull of human extraocular muscle. In microscopic exam, some Inflammatory cells and fibrosis were found. The new device was technically easy, fast, and accurate, so it may be useful in stabismus surgery.

곰쓸개 복용 후 발생한 육안적 혈뇨와 신유두부 괴사증 1예

김우진,한민석,김수항,박인형,박진석,선제형,홍세인,박옥영,신정현,이숭,신병철 朝鮮大學校 附設 醫學硏究所 2006 The Medical Journal of Chosun University Vol.31 No.3

Renal papillary necrosis occurs most commonly in association with urinary tract infection, diabetes mellitus, sickle cell disease, vascular disease, and analgesic nephropathy. Clinical presentation may be related to symptoms of pyelonephritis such as flank pain, renal colic, hematuria, Proteinuria, recurrent fever. The necrotic tissue may be sloughed off, and the diagnosis can sometimes be made by finding piece of renal medullary tissue in the urine. Pyelography may demonstrate cavities and sinuses in the resion of papillae. Anuria & oliguria can lead to the acute renal failure, and especially prognosis and progress may be affect influenced by urinary infection. We report a case of renal papillary necrosis with ingestion of bear gallbladder. On pyelography, Persistent contrast is diagnostic clue of renal papillary necrosis. This case is not be related to urinary tract infection, but occurred acute renal failure. Expectant treatment was gone.

CaO-SiO_2-MgO_(sat.)-Fe_tO 슬래그와 용철사이의 V 평형분배비

金抗洙,鄭雨光,趙南敦,崔鉉洙 대한금속재료학회 2002 대한금속·재료학회지 Vol.40 No.4

The equilibrium study has been made on the vanadium distribution between CaO-SiO_2-MgO_ast.-Fe_tO slag and liquid iron over the temperature range from 1540℃ to 1640℃. The vanadium distribution ratios(L_v) were approximately larger than phosphorous distribution ratios(L_p) by a factor of 10∼100 times. The L_v dependence on slag composition and temperature was found to be similar to the case of L_p. The vanadium distribution ratio increases with the slag basicity and Fe_tO content in slag, but decreases with the increase of temperature. A linear relationship was observed between logarithm of (V)/{[V][O]^n} (n=2 or 2.5) and (CaO+0.3MgO)/SiO_2. It is assumed that the vanadium ion is in the form of V^4+ or V^5+ in slag. The mutual function relating the slag components, F_s=0.58(CaO/ SiO_2)+0.025Fe_tO, was introduced to explain quantitatively the influence of slag composition on the vanadium distribution ratio. The log values of vanadium distribution ratio as a function of Fs were derived at the fixed temerature of 1590℃ and 1640℃.

연속철근 콘크리트 포장체의 피로수명에 대한 실험적 연구

김형수,윤기용 선문대학교 1999 공과대학논문집 Vol.1 No.2

시멘트 콘크리트 포장은 대형 차량 하중에 대한 지지력이 좋고 수명이 길며, 시공 후에 잦은 유지 보수가 필요치 않다는 측면에서 국내 고속도로에는 1980년대 도입된 이후부터 그 사용이 급격히 증가하였으며, 앞으로 건설되는 대규모 고속도로들도 콘크리트 포장으로 시공할 가능성은 증가하고 있다. 이에 본 연구에서는 균열에 의한 Punch-Out 파괴에 따른 콘크리트 포장의 수명을 규명하기 위하여 이론적 연구와 정적하중재하실험을 바탕으로 1/4로 상사한 시험체를 제작하였다. 콘크리트포장의 수명을 지배하는 파괴모드를 Punch-Out으로 가정하고, 피로하중의 응력수준을 Punch-Out이 발생할 때의 하중인 정적파괴하중으로부터 산정하여 피로실험을 실시하였다. 피로실험결과로부터 기존의 콘크리트포장의 파괴기준식과 비교한 결과 Vesic에 의한 결과와 잘 일치하는 것을 보여 주었다. 본 실험은 온도변화에 의한 열응력이나 동결융해 등의 환경적 요인이 배제되었으므로 피로수명의 상한값을 제시한다. The use of cement concrete pavement in the roadway system has increased since its first application in 1980's in Korea by virtue of its good durability and excellent load-resisting capacity. in this study, six 1/4 reduce specimens were tested to investigate the fatigue life expectancy of continuously reinforced concrete pavements(CRCP). A series of fatigue tests were performed with varying fractions of the static failure load thus determined by several static tests and finite element analyses. The results were shown very close to those based on the field study performed by Vesic in 1970. Nothing that the present tests do not include the environmental factors such as temperature stress such as temperature changes, and freezing and thawing, the fatigue life expectance determined from the present tests should be interpreted as upper bound values.

CaO-SiO₂-MgO_(sat.)-Fe_(t)O 슬래그와 용철사이의 V 평형분배비

김항수,정우광 국민대학교 2002 北岳論叢 Vol.19 No.-

Equilibrium experiments have been made to study the vanadium distribution between CaO-SiO₂-MgO_(sat.)-Fe_(t)O slag and liquid iron in the temperature range from 1540℃ to 1640℃. The vanadium distribution ratios were larger approximately by a factor of 100 times than those for phosphorous. The dependence of vanadium distribution ratio on slag composition and temperature is found to be quite similar to that for phosphorous. The vanadium distribution ratio is increased with the increase of slag basicity and Fe_(t)O content in slag. The vanadium distribution ratio is decreased with the rise in temperature. A linear relationship was observed between logarithm of (V)/{[V][O]n} (n=2 or 2.5) and (CaO+0.3MgO)/SiO₂ ratio. It is assumed that the vanadium ion is in the form of V^(4+) or V^(5+) in slag. The function of slag composition, Fs=0.58(CaO/SiO₂)+0.025Fe_(t)O, was introduced to represent the influence of the slag composition quantitatively on the vanadium distribution ratio. Equations for the vanadium distribution ratio using the function of slag composition were derived for 1590°C and 1640℃.

DS/CDMA 시스템에서 핸드오프 방식에 따른 얼랑용량과 링크마진 계산에 의한 셀 커버리지

권영수,김항래,한태영,김남 충북대학교 컴퓨터정보통신 연구소 2002 컴퓨터정보통신연구 Vol.10 No.2

PCS CDMA 시스템의 역방향 링크에서 핸드오프 기법에 따라 얼랑용량과 링크마진을 구하는 각각의 차단확률을 유도하였다. 동일한 시스템 파라메터로 그 값을 계산해서 COST-231 전파모델을 적용한 전파손실을 구할 때 적용하였으며, 현실적인 셀 최대용량으로 얼랑용량을 계산해 여러 지역에서 셀 커버리지와의 관계를 새로운 관점에서 분석하였다. 소프트핸드오프를 하는 상황에서 E_(b)/N_(o)=5 dB에서 차단확률을 5 %에서 2 %로 낮출 경우 링크마진은 0.88 dB 더 높여야하고 용량이 20 얼랑에서 2 얼랑 감소함에 따라 도시지역의 셀 커버리지도 0.1 km 줄어들지만 신뢰성과 서비스품질을 높일 수 있었다. 차단확률 5 % 이내에서 E_(b)/N_(o)=7 dB에서 5 dB로 낮게 적용할 경우 마진은 똑같이 2.8 dB로 적용해도 용량은 11 얼랑에서 9 얼랑 증가와 함께 커버리지도 1.5 km에서 0.2 km 증가하였다. 이때 하드핸드오프에 비하면 2.16 dB의 마진을 더 줄일 수 있어 10 얼랑 증가와 함께 0.22 km 늘어나는 소프트핸드오프 이득이 발생하였다. 또한 핸드오프를 하지 않는 단일 셀 경우에 비해서는 용량은 10 얼랑 이상 감소하지만 1.31 dB의 마진을 줄일 수 있어 셀 커버리지도 0.17 km 증가하였다. We derive the outage probability for the Erlang capacity and link margin according to handoffs in the reverse link of a PCS CDMA system, calculate them with the same parameters, and then analyze newly the cell coverage with the maximum realizable Erlang capacity in different areas by the COST-231 model. If it decreases from 5 % to 2 % in case of E_(b)/N_(o)=5 dB, the result shows a very reliable link on the additional increase of 0.88 dB in the margin and a high quality of service within coverage decrease of 0.1 km from 1.5 km in city area on the decrease of 2 Erlang from 20 Erlang in the capacity. When the E_(b)/N_(o) decreases from 7 dB to 5 dB within the outage probability of 5 % under a soft handoff, it shows the increase of 9 Erlang from 11 Erlang and of 0.2 km in it on the same margin of 2.8 dB. Then, comparing it with a hard handoff, it shows the soft handoff gain of the decrease of 2.16 dB in the margin, the increase of 10 Erlang, and of 0.22 km in it. Also, comparing it with a single cell, the decrease of more than 10 Erlang, but the enlargement of 0.17 km on the decrease of 1.31 dB.