Adaptive Maximum Power Point Tracking Algorithm for Photovoltaic Power Systems

AHN, Chang Wook,CHOI, Ju Yeop,LEE, Dong-Ha,AN, Jinung The Institute of Electronics, Information and Comm 2010 IEICE TRANSACTIONS ON COMMUNICATIONS - Vol.93 No.5

<P>This paper presents an adaptive maximum power point tracking (MPPT) algorithm. The aim is to dynamically adjust the step length for updating duty ratio (or operating voltage) so as to make full utilization of the output power of photovoltaic (PV) systems, even under the rapidly changing atmospheric conditions. To this end, the average slope in terms of voltage and power is exploited for reducing the harmful effect of noise and error (incurred in measurement or quantization) on the slope. Also, a statistical decision-making scheme is employed for reliably deciding the time instant at which atmospheric conditions actually change. Empirical study has adduced grounds for its dominance over existing references.</P>

알코올 용매로부터 알콕사이드졸겔법에 의한 알루미나 미분말의 제조

김창은,이해욱,안용진,김배연 연세대학교 산업기술연구소 1989 논문집 Vol.21 No.1

Al(??)₃를 알코올 용매하에 아세틸아세톤과 반응시킨 후 부분가수분해 하여 alumina precusor sol을 얻었다. 생성된 졸의 특성을 알아보기 위하여 산의 농도에 따른 졸의 상태를 조사하였다. 또한 이 졸로부터 얻어진 분말은 각 온도별로 열처리하여 결정의 전이과정 및 각 온도에서의 결정상태 등을 조사하였다. 건조분말은 90℃에서 비정질로서 polymenc sol의 특성을 나타내었으며 900℃에서는 ? -Al₂O₃, 1050 ℃에서는 α- Al₂O₃의 단일상이 각각 관찰되었다. 또, 비정질분말과 α- Al₂O₃에서는 6배위한 Al을, 그리고 ??-Al₂O₃에서는 4배위한 Al을 각각 확인할 수 있었다. Alumina precusor sol was obtained by the reaction of Al(??)₃ and acetylacetone in the alcohol solvent followed by the partial hydrolysis. In order to investigate the characteristics of the obtained sol, the state of the sol with the concentration of the acid was investigated. The powders obtained from this sol were calcined at the various temperatures. The transition of crystals and crystal state were investigated at the various temperatures. The powders dried at 90 ℃ showed the characteristies of polymeric sol and at 900℃ showed ??-Al₂O₃, at 1050℃ showed the single phase of α-Al₂O₃.

刺鍼의 副作用에 關한 文獻的 考察

許成旭,安昌範 동의대학교 한의학연구소 1998 동의한의연구 Vol.2 No.-

The side effect is due to conditions such as weakness, anxiety, fatigue, excessive sweating, starvation, severe diarrhea, heart disease, infections, news injuries and untolerable acupuncture stimulations. The slight symptoms are dizziness, nausea, vomiting and palpitation and for them warm tea and message are very effective. The severe symptoms are pallor, extremities-coldness, sensory disturbance and feinting and applied to the points such as Tong tian(BL7), Zusanli(ST36), Baihui(GV2O), Cheng jiang(CV24) and Shuigou(GV26)

열화된 HK40 강의 마식특성에 관한 연구

김창훈,김엄기,전용두,이금배,남승훈,안병욱 한밭대학교 생산기반기술연구소 2003 생산기반기술연구소 논문집 Vol.3 No.1

The erosion behavior of artificially aged HK40 steel was invested. Erosion tests were conducted at room temperature, 200℃ and 400℃ using Al_2O_3 particles. Erosion rates increased with the increment of temperature. The maximum erosion rate appeared with the impingement angle of 30 degree. The erosion rate increased, reached the maximum at 1000 hours, and after that, decreased with the heat treatment time. The mechanism of erosion seems to be the cutting wear which is very much associated with the strength of material. As results, the erosion rates were rather affected by the tensile strength and the strain hardening coefficient than the hardness and the yield strength. Such changes of material properties would be caused by the change of micro-structure due to the precipitation of carbide and the dissolution of solid element within matrix during the heat treatment.

皮膚疾患(?疹 , 濕疹 , 紛刺鍼)의 鍼灸治療에 關한 文獻的 考察

許成旭,安昌範 동의대학교 한의학연구소 1998 동의한의연구 Vol.2 No.-

Literary review on the acupuncture treatments for sfin diseasea(urticaria, eczema and acne). The purpose of this study was to investigate acupuncture treatments for skin diseases. The methods are focused on (expelling wind-damp) (heat-clearing) (blood-harmony) (transport function of stomach and spleen). Among acupuncture points, were mostly used points such as Zusanli(ST36), Quchi(LI11) and Sanyinjiao(SP6)

2 CASES OF RABBIT SYNDROME : 토끼증후군 2례

민병근,이창화,안준호,천두욱,김헌수 울산대학교 의과대학 1994 울산의대학술지 Vol.3 No.2

The application of neuroleptics to schizophrenic and other psychotic patients in the early 1950's led to the therapeutic revolution into the psychiatry, on the other hand neuroleptic-related adverse effects did frequently occur. The authors experienced 2 cases of rabbit syndrome producing by rare complication of neuroleptic medication. Two cases were examined for the rabbit syndrome by the description of Villeneuve(1972) and Sovner and DiMascio(1977). The reciprocal coordination test and the finger-tapping technique to worsen the symptoms also were applied to two patients. The authors emphasized two issues of rabbit syndrome as follows. First, though the literature search showed that the majority of patients presented with rabbit syndrome which is usually seen after a prolonged exposure to neuroleptic medication with the more potency in the middle or elderly aged are over 45 years old, we suggest that this syndrome might be linked to the younger age factor and the low potency thioridazine in our patient. Second, the rabbit syndrome is in the importance of the clinical practice because of being readily reversible with antiparkinsonian agents or anticholinergic drugs. In addition, recognizing this condition and differentiating it from tardive dyskinesia helps in the choice of the proper treatment of orofacial disorders following neuroleptic medication for the long time.

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.

Comparison of Netarsudil/Latanoprost Therapy with Latanoprost Monotherapy for Lowering Intraocular Pressure: A Systematic Review and Meta-analysis

Jong-Wook Lee(Jong-Wook Lee),Hyeon-Soo Ahn(Hyeon-Soo Ahn),Jinho Chang(Jinho Chang),Hye-Young Kang(Hye-Young Kang),Dong-Jin Chang(Dong-Jin Chang),Jae Kyung Suh(Jae Kyung Suh),Hankil Lee(Hankil Lee) 대한안과학회 2022 Korean Journal of Ophthalmology Vol.36 No.5

Purpose: Netarsudil is a Rho kinase inhibitor and the first new class of clinically useful ocular hypotensive agents. In this study, we conducted a systematic literature review and meta-analysis to summarize and synthesize the available evidence on the efficacy and safety of fixed-dose combination (FDC) therapy with netarsudil/latanoprost in patients with glaucoma. Methods: We identified relevant studies in PubMed, Ovid Medline, Embase, and Cochrane Central until April 2021. The quality of the studies and the level of evidence were assessed using the Risk of Bias tool. Efficacy was measured as the mean difference in reducing intraocular pressure (IOP), and safety was assessed by the risk of conjunctival hyperemia (CH) due to FDC therapy, netarsudil monotherapy, or latanoprost monotherapy. Results: Four studies met the predefined eligibility criteria and were included in the meta-analysis. The mean difference in the reduction in IOP after 2 weeks and 4 to 6 weeks of drug administration was -2.41 mmHg (95% confidence interval [CI], -2.95 to -1.87) and -1.77 mmHg (95% CI, -2.31 to -1.87), respectively, in patients receiving FDC therapy versus those receiving latanoprost monotherapy. On the other hand, latanoprost monotherapy had a greater effect in reducing IOP than netarsudil monotherapy after 4 to 6 weeks of administration (mean difference, 0.95 mmHg; 95% CI, 0.43 to 1.47). The risk of CH was significantly higher with both FDC therapy and netarsudil monotherapy compared to latanoprost monotherapy in week 12, where the relative ratio was 3.01 (95% CI, 1.95 to 4.66) and 2.33 (95% CI, 1.54 to 3.54), each. Conclusions: Netarsudil/latanoprost FDC therapy has a significantly greater effect on reducing IOP than latanoprost alone. The symptoms of CH were mostly mild, and only a few glaucoma patients discontinued the medication owing to CH in earlier clinical trials. Therefore, it would be beneficial to consider the administration of netarsudil/latanoprost FDC therapy in patients with glaucoma.

Comparison of Intracorporeal Reconstruction after Laparoscopic Distal Gastrectomy with Extracorporeal Reconstruction in the View of Learning Curve

Ahn, Chang Wook,Hur, Hoon,Han, Sang-Uk,Cho, Yong Kwan The Korean Gastric Cancer Association 2013 Journal of gastric cancer Vol.13 No.1

Purpose: The intracorporeal reconstruction after laparoscopic gastrectomy can minimize postoperative pain, and give better cosmetic effect, while it may have technical difficulties and require the learning curve. This study aimed to analyze the surgical outcome of intracorporeal reconstruction according to the surgeon's experience comparing with extracorporeal procedure. Materials and Methods: From January 2009 to September 2011, intracorporeal reconstruction in laparoscopic surgery for gastric cancer was performed for 71 patients (Intra group). During same period, 231 patients underwent laparoscopy-assisted gastrectomy (Extra group). These patients were classified into initial (1st to 20th case of intra group), intermediate (21th to 46th case), and experienced (after 47th case) phases. Results: Intracorporeal procedures included 35 cases of Billroth-I, 30 Billroth-II and 6 Roux en Y reconstructions. In the initial phase, operation time (P=0.022) were significantly longer for the patients of intra group than them of extra group. Although the difference was not significant, the length of hospital stay was longer and complication rate was higher in the intra group. In intermediate and experienced phases, there was no difference between two groups in operation time and hospital stay. In these phases, complication rate was lower in the intra group than the extra group (3.9% versus 9.7%). The pain scale was significantly lower post operation day 5 in the intra group. Conclusions: Intracorporeal reconstruction after laparoscopic distal gastrectomy was feasible and safe, and the technique was stabilized after 20th case if the surgeon has sufficient experiences when we compared it with extracorporeal reconstruction.

A brief review on relaxor ferroelectrics and selected issues in lead-free relaxors

Ahn, Chang Won,Hong, Chang-Hyo,Choi, Byung-Yul,Kim, Hwang-Pill,Han, Hyoung-Su,Hwang, Younghun,Jo, Wook,Wang, Ke,Li, Jing-Feng,Lee, Jae-Shin,Kim, Ill Won 한국물리학회 2016 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol. No.

<P>Relaxor ferroelectricity is one of the most widely investigated but the least understood material classes in the condensed matter physics. This is largely due to the lack of experimental tools that decisively confirm the existing theoretical models. In spite of the diversity in the models, they share the core idea that the observed features in relaxors are closely related to localized chemical heterogeneity. Given this, this review attempts to overview the existing models of importance chronologically, from the diffuse phase transition model to the random-field model and to show how the core idea has been reflected in them to better shape our insight into the nature of relaxor-related phenomena. Then, the discussion will be directed to how the models of a common consensus, developed with the so-called canonical relaxors such as Pb(Mg1/3Nb2/3)O-3 (PMN) and (Pb, La)(Zr, Ti)O-3 (PLZT), are compatible with phenomenological explanations for the recently identified relaxors such as (Bi1/2Na1/2)TiO3 (BNT)-based lead-free ferroelectrics. This review will be finalized with a discussion on the theoretical aspects of recently introduced 0-3 and 2-2 ferroelectric/relaxor composites as a practical tool for strain engineering.</P>