Improvement of Desulfurization Efficiency via Numerical Simulation Analysis of Transport Phenomena of Kanbara Reactor Process

Yong‑Joon Lee,Kyung‑Woo Yi 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.4

The Kanbara reactor (KR) process is a mechanical stirring method that reacts hot metal with desulfurization flux; it is a widelyimplemented desulfurization method in contemporary steel production. This study aimed to develop a new impeller profilefor improving the desulfurization efficiency of the KR process. We implemented operational data analysis, a computationalfluid dynamics simulation based on the operational data and performed testing and analysis with impeller models on-site aproduction facility. Operational data from the production facility was gathered over a 3-year period. Seven impeller modelswith varying impeller blade width (top and bottom), height, inclination, and curvature (curved, straight, and combination)were simulated. The results were analyzed to determine the optimal conditions. A new impeller design was selected for onsiteoperational testing to investigate the in situ desulfurization efficiency over 350 charges, and the results corroborated thepredictions by the numerical simulations. It is expected that the proposed process modification can be successfully used forimproving industrial desulfurization efficiency.

Light-extraction efficiency control in AlGaN-based deep-ultraviolet flip-chip light-emitting diodes: a comparison to InGaN-based visible flip-chip light-emitting diodes.

Lee, Keon Hwa,Park, Hyun Jung,Kim, Seung Hwan,Asadirad, Mojtaba,Moon, Yong-Tae,Kwak, Joon Seop,Ryou, Jae-Hyun Optical Society of America 2015 Optics express Vol.23 No.16

<P>We study light-extraction efficiency (LEE) of AlGaN-based deep-ultraviolet light-emitting diodes (DUV-LEDs) using flip-chip (FC) devices with varied thickness in remaining sapphire substrate by experimental output power measurement and computational methods using 3-dimensional finite-difference time-domain (3D-FDTD) and Monte Carlo ray-tracing simulations. Light-output power of DUV-FCLEDs compared at a current of 20 mA increases with thicker sapphire, showing higher LEE for an LED with 250-관m-thick sapphire by ~39% than that with 100-관m-thick sapphire. In contrast, LEEs of visible FCLEDs show only marginal improvement with increasing sapphire thickness, that is, ~6% improvement for an LED with 250-관m-thick sapphire. 3D-FDTD simulation reveals a mechanism of enhanced light extraction with various sidewall roughness and thickness in sapphire substrates. Ray tracing simulation examines the light propagation behavior of DUV-FCLED structures. The enhanced output power and higher LEE strongly depends on the sidewall roughness of the sapphire substrate rather than thickness itself. The thickness starts playing a role only when the sapphire sidewalls become rough. The roughened surface of sapphire sidewall during chip-separation process is critical for TM-polarized photons from AlGaN quantum wells to escape in lateral directions before they are absorbed by p-GaN and Au-metal. Furthermore, the ray tracing results show a reasonably good agreement with the experimental result of the LEE.</P>

수근관 증후군에서의 무증상성 척골신경병증

문준식,이성수,이지용,한범기,권준범,양현덕,이성익 대한신경과학회 1999 대한신경과학회지 Vol.17 No.2

정신분열병에 대한 리스페리돈의 효과 및 안정성

이민수,김용구,김영훈,연병길,오병훈,윤도준,윤진상,이철,정희연,강병조,김광수,김동언,김명정,김상훈,김희철,나철,노승호,민경준,박기창,박두병,백기청,백인호,손봉기,손진욱,양병환,양창국,우행원,이정호,이종범,이홍식,임기영,전태연,정영조,정영철,정인과,정인원,지익성,채정호,한상익,한선호,한진희,서광윤 大韓神經精神醫學會 1998 신경정신의학 Vol.37 No.1

연구목적 : 본 시험의 목적은 임상시험 시작전에 연구자들을 대상으로 PANSS Workshop을 통하여 PANSS, ESRS에 대한 국내에서의 표준화 작업을 구축하고 새로운 정신병 치료제인 리스페리돈의 효과와 안정성을 재확인하여 리스페리돈 사용에 대한 적정화를 이루는데 있다. 연구방법 : 1996년 4월부터 1996년 9월까지 국내 39개 대학병원 정신과에 입원중인 혹은 증상이 악화되어 입원하는 정신분열병 환자 377명을 대상으로 다시설 개방 연구를 시행하였다. 1주일간의 약물 배설기간을 가진후, 리스페리돈을 8주간 투여하였고, 기준점, 1주, 2주, 4주, 그리고 8주후에 평가되었다. 용량은 제1일에는 리스페리돈 1mg씩 1일 2회, 제2일에는 2mg씩 1일 2회, 제3∼7일에는 3mg씩 1일 2회 투여하였다. 이후 환자의 임상상태에 따라 임의로 증량할 수 있으며, 최대 일일 16mg을 초과하지 않도록 하였다. 추체외로 증상을 조절하기 위한 투약을 허용하였다. 임상증상 및 부작용의 평가는 PANSS(Positive and Negative Syndrome Scale), CGI(Clinical Global Impression) 그리고 ESRS(Extrapyramidal Symptom Rating Scale)을 사용하였다. 연구결과 : 377명중 343명(91%)이 8주간의 연구를 완결하였다. 치료 종결시점인 8주후 PANSS 총점수가 20% 이상 호전된 경우를 약물 반응군으로 정의할때, 약물반응군은 81.3%였다. 리스페리돈에 반응하는 예측인자로는 발병연령, 이전의 입원 횟수, 유병기간이 관련 있었다. 리스페리돈은 1주후부터 PANSS양성, 음성, 및 일반정신병리 점수상에 유의한 호전을 보여 효과가 빨랐다. CGI의 경우도 기준점에 비해 1주후부터 유의한 감소를 나타내었다. ESRS의 경우, 파킨슨 평가점수는 기준점과 비교해 투여 1주, 2주, 4주후 유의하게 증가되었다가 8주후 기준점과 차이가 없었다. Dystonia 평가점수는 1주후만 유의한 증가를 보였으며, dyskinesia 평가점수는 유의한 차이가 없었다. 혈압, 맥박수의 생명징후 및 일반 혈액학 검사, 생화학적 검사, 심전도 검사에서 유의한 변화는 없었다. 결 론 : 이상의 다시설 개방 임상 연구를 통해 리스페리돈은 정신분열병 환자에서 양성증상뿐만 아니라 음성증상 및 전반적인 증상에도 효과적인 것으로 사료된다. 보다 명확한 평가를 위해서는 다른 항정신병약물과의 이중맹검 연구가 필요할 것으로 생각되며, 또한 장기적 치료에 대한 평가도 함께 이루어져야 하겠다. Objective : The purpose of this study was to investigate the efficacy and safety of risperidone in the treatment of Korean schizophrenic patients. Method : This multicenter open study included 377 schizophrenic patients drawn from 39 university hospitals. After a wash-out period of 1 week, the schizophrenic patients were treated with risperidone for 8 weeks and evaluated at 5 points ; at baseline, and 1, 2, 4 and 8 weeks of treatment. The dose was increased from 2mg/day(1mg twice daily) to 6mg/day(3mg twice daily) during the first week and adjusted to a maximum of 16mg/day over the next 7 weeks according to the patient's clinical response. Medication to control extrapyramidal symptoms was permitted. The psychiatric and neurological status of the patients was assessed by PANSS, CGI, and ESRS scales. Results : 343(91%) of 377 patients completed the 8-week trial period. Clinical improvement, as defined by a 20% or more reduction in total PANSS score at end point, was shown by 81.3% of patients. The predictors of response to risperidone were associated older age, shorter duration of illness, fewer previous hospitalization. Risperidone had rapid onset of action ; a significant decrease of the total PANSS and three PANSS factor(positive, negative, general), and CGI was already noticed at the end of first week. For the ESRS, parkinsonism rating scores were significantly increased until week 4 comparing with baseline. Dystonia rating scores were significantly increased until week 1, and dyskinesia rating scores were not significantly changed during the study. Laboratory parameters including vital sign, EKG, hematological, and biochemical values showed no significant changes during the trial. Conclusions : This study suggests that risperidone is generally safe and effective against both the positive and negative symptoms in our group of patients.

서울의 Penicillinase Producing Neisseria gonorrhoeae 발생빈도(1998)

김재홍,김준호,반재용,이정우,황성주,정준규,정성태,강진문,조흔정,홍창의,정혜신,이한승,김이선,이봉길,이종호,선영우,한기덕,윤성필,이성훈,안종성,박석범,문승현,조항래,김형섭,류지호,황재영,박준홍,손상욱 한양대학교 의과대학 2001 한양의대 학술지 Vol.21 No.1

In recent years, gonorrhea has been pandemic and remains one of the most common STDs in the world, especially in developing countries. For the detection of a more effective therapeutic regimen and assessing the prevalence of Penicillinase Producing Neisseria gonorrhoeae(PPNG), we have been trying to study the patients who have visited the Venereal Disease Clinic of Choong-Ku Public Health Center in Seoul since 1980 by menas of the chromogenic cephalosporin method. In 1998, 93 strians of N. genorrhoeae were isolated, among which 60(64.5%) were PPNG. The prevalence of PPNG in Seoul, which had been decreased to 39% in 1996 after a peak of 74.3% in 1993, is increased to 64.5% in 1998.

서울의 Penicillinase Producing Neisseria Gonorrhoeae 발생빈도(1996)

김재홍,황동규,전재홍,김윤석,김중환,김용준,이창균,임동진,김현수,조창근,김경문,박상훈,전우형,김희성,이호정,차명수,김갑형,김형석,김석우,황지환,박병순,권오상,이민수,송기훈,성소영,이인섭,부태성 대한화학요법학회 1999 대한화학요법학회지 Vol.17 No.2

Background : In recent years, gonorrhea has been panedemic and remains one of the most commom STDs in the world, especially in developing countries. Objective & Methods: For the detection of a more effective therapeutic regimen and assessing the prevalence of PPNG, we have been trying to study the patients who have visited the VD Clinic of Choong-Ku Public Health Center in Seoul since 1980 by means of the chromogenic cephalosporin method. Results: In 1996, 139 strains of N. gonorrhoeae were isolated, among which 53(39.0%) were PPNG. Conclusion: Our results suggests that after a peak of 74.3% in 1993, the prevalence of PPNG in Seoul is gradually declining.

미세혈관 수술후 Urokinase투여효과에 관한 실험적 연구

이세일,오석준,김용성,양경무 大韓成形外科學會 1987 Archives of Plastic Surgery Vol.14 No.1

However, even the most technically perfect anastomosis can neither eliminate the damage which microneedles cause on the vascular endothelium nor foreign body reaction to the suture material. Thrombosis developed at the suture site and regressed if the stimulus for the thrombosis is not severe. Partial thrombosis was inevitable after microvascular anastomosis. Since systemic thrombolytic drugs were used initially in the management of pulmonary emboli, urokinase were also used in prevention of thrombolysis and thrombolysis after microvascular anastomsis. This experimental study includes the effect of urokinase on the microvascular anastomosis in rabbits. The patency was observed, and platelet count, fibinogen, prothrombin time, and activated partial thromboplastim time were examined. In the case of thromboses, the anastomotic sites were resected and examined microscopically. The results were as follow; 1. The patency rate was increased 15 percent in experimental group than control group. 2. There were no differences in platelet count and the prothrombine time between experimental and control group. 3. The level of fibrinogen was decreased 157㎎/dl in experimental group less than control group. 4. The activated partial thromboplastin time was increased three to four times at postoperative period more than preoperative period in experimental group. 5. In light microscopic examination of thrombotic vessel wall revealed inflammatory reaction to suture material. In the experimental group, the thrombi were loose and defibrinated than control group.

졸 - 겔법에 의한 다공성 알루미나 미분체 제조에 관한 연구 : 2 . 물과 알콕시드의 비가 알루미나 미분체의 결정화 공정에 미치는 영향 2 . The Effect of [ H2O ] / [ Al - alkoxide ]on The Crystallization Mechanism of As - Prepared Particles

이성원,박형상,윤호성,황운연,구기갑,유승준,김용렬,이정운 한국화학공학회 2001 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.39 No.2

알루미늄 알콕시드의 반응속도를 제어하기 위한 혼합용매와 입자제조 과정에서의 응집을 방지하기 위한 분산제로 HPC를 첨가하는 방법에 의하여 구형의 다공성 알루미나 미분체를 제조하였으며, XRD, FT-IR 및 TG-DTA 분석을 통하여 공정변수로 선정한 물과 알루미늄 알콕시드의 비가 제조된 미분체의 결정화 공정에 미치는 영향에 대하여 고찰하였다. 축중합 반응에 첨가된 물과 Al-알콕시드의 비는 제조된 미분체 및 하소 공정을 거친 미분체의 결정구조에 영향을 미침을 알 수 있었다. [H₂O]/[ASB]의 비가 증가할수록 제조된 미분체는 비정질의 Al(OH)₃로부터 점진적으로 AlO(OH)의 화학조성을 갖는 의사-보헤마이트로 결정성이 바뀌었다. 그리고 건조 공정을 거친 미분체의 결정성이 좋을수록 δ와 θ-Al₂O₃는 저온에서 생성되었으나, α-Al₂O₃는 고온에서 생성되었다. 이와 같은 결과는 Al^(3+)이온의 결정 내에서의 배위체 변화와 관계됨을 알 수 있었다. 그리고 [H₂O]/[ASB]=2의 조건에서 제조된 입자는 다른 시료와 달리 600℃에서 η-Al₂O₃로 1,100℃에서 α-Al₂O₃2로 상전이 되었다. Spherical porous alumina particles were prepared by mixed solvent to control the reaction rate of Al-alkoxide and the particle shape with hydroxy-propyl cellulose(HPC). HPC was used as a dispersant to prevent aggregation during the formation of particles. The effect of [H₂O]/[ASB] ratio on the crystallization reactions of as-prepared particles was studied by XRD, FT-IR, and TG-DTA analysis. The mole ratio of water and Al-alkoxide added in the condensation reaction had an important effect on the crystal structure of as-prepared particles and the calcined particles. As the [H₂O]/[ASB] ratio increase, the crystal structure of as-prepared particles was continuously varied from amorphous Al(OH)₃ to pseudo-boehmite with chemical composition of AIO(OH). The samples which have higher crystallinite after drying process were transformed into the δ- and θ-Al₂O₃ at lower calcination temperature, but these sample were transformed into α-Al₂O₃ at higher calcination temperature. This result was thought to be the transformation of the coordination number of Al^(3+) ion in the crystal structure. The particles prepared by [H₂O]/[ASB]=2 condition crystallized to α-Al₂O₃at 600℃ and converted to η-Al₂O₃at 1,100℃ without intermediate phases.

Olanzapine 복용 이후 당뇨병 케톤산증이 발생한 정신분열병 환자

이중선,김진용,안준호,김창윤 大韓神經精神醫學會 2005 신경정신의학 Vol.44 No.1

The use of olanzapine has been associated with clinically significant hyperglycemia (exacerbation of existing diabetes, new-onset type 2 diabetes and diabetic ketoacidosis). We report a case of diabetic ketoacidosis (DKA) in 30-year-o1d male patient with schizophrenia who was on olanzapine. When he was admitted to the hospital because of DKA, he had been taking olanzapine for 43 months. 14 months before the admission, his fasting and 2 hour postprandial serum glucose levels were normal. He had no personal and family history of diabetes mellitus. He had no risk factor for diabetes mellitus except for obesity (body mass index : 39.2 kgW). He also hadno precipitating factors for DKA such as infection or myocardial infarction. Periodic monitoring for changes in serum glucose levels in patients taking olanzapine may be needed.

방사선 조사후 아크릴릭 레진의 물성변화

이용근,이건일,박영준,변호영 원광대학교 생체재료·매식연구소 1995 원광생체재료·매식 Vol.4 No.2

To investigate the effect of high dose irradiation on the mechanical properties. dental acrylic resin specimens were irradiated and the Vickers hardness number(VHN) and the 3-point flexure strength(FS) were measured before and after irradiation. Five kinds of acrylic resins were studied. Two(VRS. PS2) were heat cured denture base resins. one(VSC) was chemically cured denture base resin and the other two(ORJ, VOP) were orthodontic resins. The acrylic resin specimens were made according to the manufacturer's instructions and were finally polished with Microcloth (Buehler). Among ten specimens of each material. five specimens were irraditated with 100 Gy using a linear accelerator (Mitsubishi 6 MV), and the others were not. The specimens were immersed in 37℃ D.W. for 48 hours before testing. Each specimens the VHN was measured 10 times. Their FS was measured with an universal testing machine (Instron 4302, England), with a cross-head speed of 5 mm/min. The VHNs of heat cured resins were 21.52∼25.55 kg/㎟ before irradiation and 19.93∼26.58 kg/㎟ after irradiation. Those of chemically cured resins were 11.28∼16.6kg/㎟ before irradiation and 11.3∼14.3 kg/㎟ after irradiation. The VHNs of heat cured acrylic resins were significantly higher than those of chemically cured resins were significantly higher than those of chemically cured resins before and after irradiation(p<0.05). VHN of VRS was significantly increased after irradiation, and those of VOP and PS2 were significantly decreased after irradiation (p<0.05). The FS of resins studied were 6.7∼8.0 kg/㎟ before irradiation and 6.5∼8.4 kg/㎟ after irradiation. The FS of VSC and VRS increased after irradiation and those of VOP, ORJ and PS2 decreased after irradiation, but the results were not statistically significant. Before irradiation, the FS of heat cured resins were somewhat higher than those of chemically cured resin, but not statistically significant, and after irradiation the FS of heat cured resins were significantly higher than those of orthodontic resins. In conclusion. high dose irradiation did not result in consistent changes in mechanical properties.