실시간 In-situ IR을 이용한 Glycidyl Azide Monomer(GAM)의 양이온중합 반응속도 연구

김형석,김관영,강신춘,노시태,김진석,유재철,최근배,Kim, Hyoung-Sug,Kim, Kwan-Yung,Kang, Shin-Choon,Noh, Si-Tae,Kim, Jin-Seuk,Yu, Jae-Chul,Choi, Keun-Bae 한국군사과학기술학회 2009 한국군사과학기술학회지 Vol.12 No.2

We synthesized glycidyl azide monomer(GAM) as a monomer for polymerization of glycidy azide polymer(GAP) which is a promising energetic prepolymer for a plastic-bonded explosive. Using quantitative real-tim in-situ infrared(in-situ IR) spectroscopy, kinetic study on the cationic ring opening polymerization of GAM was carried out. The reaction rate was obtained from monitoring the change of ether C-O stretching band($1050cm^{-1}$) in series IR spectra. The reaction was in accordance with the first-order reaction law for each of reaction temperature at 100/1 mole ratio of [GAM]/[$BF_3*etherate$]. In the ring opening polymerization of GAM, with ratio of [GAM]/[$BF_3*etherate$] to equal 100/1 at various temperature, the activation parameters obtained from the evaluation of kinetic data were ${\Delta}H^*$=14.34kcal/mol, ${\Delta}S^*=-12.31cal/mol{\cdot}K$ and $E_a$=14.89kcal/mol.

포수제(捕收劑) 종류(種類)에 따른 공작석(孔雀石)의 부유선별(浮遊選別) 특성(特性)

김형석,김완태,한인규,김상배,Kim, Hyung-Seok,Kim, Wan-Tae,Han, In-Kyu,Kim, Sang-Bae 한국자원리싸이클링학회 2010 資源 리싸이클링 Vol.19 No.4

공작석의 부선에 적합한 포수제를 규명하기 위하여 각종 포수제의 종류에 따른 공작석의 부유선별 특성을 연구하였다. 공작석의 제타전위를 측정한 결과, 공작석의 등전점은 약 pH 8.2로, 등전점 이상의 pH에서는 공작석의 표면이 음(-)으로 하전되고, 등전점 이하에서는 양(+)으로 하전됨을 확인하였다. 공작석은 음이온 포수제인 sodium oleate와 Aeropromoter 845에 의해서 pH 5~11의 범위에서 97%이상 부유되었다. 그러나 alkyl hydroxamate 및 양이온 포수제인 dodecyl trimethyl ammonium chloride와 dodecyl ethyl methyl ammonium chloride에 의해서는 pH 5 이상에서 첨가량에 관계없이 15%미만으로 부유되었다. 공작석을 $(NH_4)_2S$로 황화처리한 후 potassium amyl xanthate로 부선하였을 때, 공작석은 97%이상 부유되었다. 이때 황화처리하지 않았을 때 보다 potassium amyl xanthate의 첨가량이 1/3 정도 적어졌고, 부선시간도 단축되었다. 따라서 공작석의 부선에 적합한 포수제는 potassium amyl xanthate와 음이온 포수제인 sodium oleate 및 Aeropromoter 845이었다. In order to select the proper collector for the flotation of malachite, we had floated malachite by using various collectors. When measuring the zeta potential of malachite, we knew that the point of zero charge of malachite is found at pH 8.2 and malachite particles are negatively charged above this pH value; and positively, below this pH value. The floatability of malachite by the anionic collectors like sodium oleate and Aeropromoter 845, was about 97% in pH 5~11 range, whereas that of malachite by alkyl hydroxamate and the cationic collector like dodecyl trimethyl ammonium chloride and dodecyl ethyl methyl ammonium chloride, was below 15% above pH 5 regardless of dosage increase of collector and flotation time. The malachite sulphidised by $(NH_4)_2S$ was floated above 97% by potassium amyl xanthate. The dosage of potassium amyl xanthate decreased and the flotation period shortened to one third than when it was not sulphidised by $(NH_4)_2S$. Therefore, potassium amyl xanthate and the anionic collectors like sodium oleate and Aeropromoter 845 can be used as the collector of malachite.

돼지의 과립막세포 종양

김형석,강상철,정지열,김현섭,김대용,김재훈,Kim, Hyeong-Seok,Kang, Sang-Chul,Jung, Ji-YouI,Kim, Hyun-Sup,Kim, Dae-Yong,Kim, Jae-Hoon 대한수의학회 2008 大韓獸醫學會誌 Vol.48 No.3

A two-year-old mixed breed sow was requested to the Veterinary Pathology Laboratory of Cheju National University with a clinical signs of severe abdominal pain and sudden death. Grossly, there was severe hemorrhage in abdominal cavity. Most of internal parenchymas and subcutaneous muscle showed severe pale discoloration. Both ovaries were enlarged with oval to round protruding multilobular masses and dark red in color. And they were firm and contained multiple small cysts in their cut surface. Histopathologically, numerous neoplastic granulosa cells had spherical-to-oval, hyperchromatic nuclei and scant eosinophilic cytoplasms were distributed with follicular pattern in ovarian masses. And the typical Call-Exner bodies, distinctive microcavityies, were observed in the center of small neoplastic follicles. Based on the gross and histopathologic findings, this case was diagnosed as granulosa cell tumor. In our best knowledge, this is believed to be the first report of granulosa cell tumor in a sow in Korea.

Trinitrotoluene의 환원반응에서 가스크로마토그래피 모니터링을 이용한 2,6-diamino-4-nitrotoluene의 합성

김형석,유재철,김호기,김새롬,최근배,정원복,서원준,김진석,Kim, Hyoung-Sug,Yu, Jae Chul,Kim, Ho Gi,Kim, Sae Rom,Choi, Keun Bae,Jung, Won Bok,Seo, Won Jun,Kim, Jin-Seuk 한국군사과학기술학회 2014 한국군사과학기술학회지 Vol.17 No.2

In this research, we investigated synthetic method of 2,6-DANT that can be used as a chain extender of urethane/urea and epoxy materials in a demilitarization method via chemical transformations considering environmental, economical aspects and stability of process. We was able to identify through GC monitoring that 2,4-DANT and 2,6-DANT were produced when we inject 'hydrazine monohydrate 3.3 eq. by TNT 1 eq.' with a fine metering pump for 30 minutes and then, reflux for an additional 2 hours. We was able to isolate only 2,6-DANT(99.3% purity and 45.0% yield) from mixture of 2,4-DANT and 2,6-DANT through the separating and refining methods using 2,6-DANT solubility in methanol and crystallinity of 2,6-DANT.

전층 각막이식 후 경면현미경, 초음파 각막두께측정계 및 Orbscan을 이용한 중심 각막두께 측정치의 비교

김형석,김준헌,김효명,송종석,Hyoung-Seok Kim,Jun Heon Kim,Hyo Myong Kim,Jong-Suk Song 대한안과학회 2007 대한안과학회지 Vol.48 No.2

Purpose: To compare the accuracy and reproducibility of central corneal thickness measured by non-contact specular microscopy, ultrasound pachymetry, and Orbscan in the post-penetrating keratoplasty eyes. Methods: Central corneal thickness was prospectively measured in eyes that had recieved penetrating keratoplasty at least 1 month before. One experienced technician measured all eyes using three methods; non-contact specular microscopy (Topcon SP-2000P; Topcon Corporation, Tokyo, Japan), Orbscan IIz (Orbtek; Bausch & Lomb, Rochester, USA), and ultrasound pachymetry (AL-2000; Tomey, Erlangen, Germany). Three consecutive measurements were performed using each method and the mean values and coefficient of variation were compared. Results: The mean values of central corneal thickness were 550.7±63.3 ?m with specular microscopy, 548.2±72.5 ?m with ultrasound pachymetry, and 472.5±151.7 ?m with Orbscan. There was no significant difference between the measurements obtained by specular microscopy and ultrasound pachymetry (p=0.53), and both methods showed high reproducibility. The corneal thickness measured by Orbscan was remarkably variable and in some patients, Orbscan was unable to measure corneal thickness. Conclusions: Non-contact specular microscopy appears to be an effective technique, potentially replacing ultrasound pachymetry for measuring central corneal thickness in the post-penetrating keratoplasty eyes.

옥탄가 변화에 따른 가솔린의 발화특성에 관한 연구

김형석,김원길,최유정,김정훈,최재욱,Kim, Hyeong Seok,Kim, Won Kil,Choi, Yu Jung,Kim, Jung-Hun,Choi, Jae-Wook 한국안전학회 2018 한국안전학회지 Vol.33 No.2

This study was conducted to assess the hazards of gasoline in relevance to the changes in octane numbers, and gasoline's spontaneous ignition temperature and instantaneous ignition temperature were measured. Spontaneous ignition temperature of regular gasoline was $301^{\circ}C$ for sample quantity of $100{\sim}125{\mu}{\ell}$. Spontaneous ignition temperature of middle gasoline was $380^{\circ}C$ for sample quantity of $125{\mu}{\ell}$ and that of premium gasoline was $400^{\circ}C$. As gasoline's octane numbers increased, their spontaneous ignition temperatures increased, and their instantaneous ignition temperature were almost identically $499^{\circ}C$ for sample quantity of $125{\mu}{\ell}$. In addition, activation energies of regular gasoline, middle gasoline, and premium gasoline were 10.48 Kcal/mol, 16.89 Kcal/mol, and 24.55 Kcal/mol respectively.

HepG2 세포의 산화적 손상에 대한 산삼 추출물의 보호효과 - DNA chip을 이용하여 -

김형석,박희수,권기록,Kim, Hyung-Seok,Park, Hee-Soo,Kwon, Ki-Rok 대한약침학회 2007 Journal of pharmacopuncture Vol.10 No.1

Objectives : This study was carried out to examine protective effect of wild ginseng extract on HepG2 human hepatoma cell line against tert-Butyl hydroperoxide (t-BHP)-induced oxidative damage. Methods : To evaluate protective effect of wild ginseng extract against t-BHP induced cytotoxicity, LDH level and activity of glutathione peroxidase and reductase were measured. Gene expression was also measured using DNA microarray. Results : Wild ginseng extract showed a significant protective effect against t-BHP-induced cytotoxicity in HepG2 cell line. It is not, however, related with the activities of glutathione peroxidase and glutathione reductase. Analysis of gene expression using DNA chip, demonstrated that 28 genes were up-regulated in t-BHP only group. Five genes - selenoprotein P, glutathione peroxidase 3, sirtuin 2, peroxiredoxin 2, serfiredoxin 1 homolog - may be related with the protective effect of wild ginseng extract. Conclusions : Based on the results, a protective effect of wild ginseng extract against t-BHP-induced oxidative damage in HepG2 cell line is not associated with the activities of glutathione peroxidase and glutathione reductase, but with the expression of selenoprotein P, glutathione peroxidase 3, sirtuin 2, peroxiredoxin 2, and serfiredoxin 1 homolog.

추간판내 Prostaglandin E₂ 양의 임상적 의의

김형석,조기홍,김기용,안영환,안영민,윤수한,조경기,Kim, Hyung Seok,Cho, Ki Hong,Kim, Ki Young,Ahn, Young Hwan,Ahn, Young Min,Yoon, Soo Han,Cho, Kyung Gi 대한신경외과학회 2000 Journal of Korean neurosurgical society Vol.29 No.10

Objective : A prospective biochemical assay of prostaglandin $E_2$ content in symptomatic lumbar disc materials was done in order to clarify the pathogenesis of lumbar radiculopathy. Patients and Methods : Forty-eight disc specimens were purified by a standard solid-phase extraction procedure and analyzed by an enzymelinked immunosorbent assay for prostaglandin $E_2$. Clinical and anatomic correlations were evaluated with analysis of variance and t-test. Results : Acute herniated lumbar disc diseases tended to be associated with a higher prostaglandin $E_2$ content than degenerative lumbar disc disease. Sequestered discs tended to be associated with a higher prostaglandin $E_2$ content than extruded discs, which also showed higher prostaglandin $E_2$ content than protruded ones. A sciatica and positive straight leg raising test appeared to be associated with a higher prostaglandin $E_2$ content than a negative test. Conclusion : This result suggests that the level of prostaglandin $E_2$ would be correlated with clinical symptom and sign in the inflammatory process of lumbar disc herniation.

Alunite와 limestone의 혼합소성에서의 무수석고의 합성

김형석,안지환,김환,신강호,조동성,Kim, Hyung-Seok,Ahn, Ji-Whan,Kim, Hwan,Shin, Kang-Ho,Cho, Dong-Sung 한국결정성장학회 2001 한국결정성장학회지 Vol.11 No.5

명반석$[K_2SO_4$.$Al_2(SO_4)_3$.$4Al(OH)_3$]을 공기분위기에서 가열하면 500~$580^{\circ}C$에서 탈수되고, 580~$780^{\circ}C$에서 $SO_3$(g)가 발생되므로 석회석과 혼합소성하였을 때의 무수석고($CaSO_4$)의 합성특성을 조사하였다. 명반석의 열분해는 $CO_2$(g) 분압에 영향이 없으나, 석회석의 경우 공기 분위기에서는 약 $650^{\circ}C$부터 분해되지만 $CO_2$(g)의 포화 분위기에서는 약 $900^{\circ}C$부터 분해된다. 명반석과 석회석을 1:6의 몰비로 혼합한 후 공기 분위기와 $CO_2$(g) 포화분위기에서 $10^{\circ}C$/min의 속도로 $1000^{\circ}C$까지 가열하여 2시간 동안 소성하면 $550^{\circ}C$에서 무수석고가, $700^{\circ}C$에서 calciumlangbeinite($(2CaSO_4$.$K_2SO_4$)가, 800~$950^{\circ}C$에서 ha yne이 형성되며 이때 무수석고의 합성량은 각각 99.0%와 95.0% 정도였다. 공기 분위기에서 무수석고 합성량은 석회석의 입도(0.5mm 이하)에 관계없이 거의 일정하지만, $CO_2$(g)의 포화분위기에서는 석회석의 입도가 작아짐에 따라 증가된다. 그러므로 명반석과 석회석을 1:6의 몰비로 혼합 소성하면 1 몰의 ha yne과 1 몰의 calciumlangbeinite로 구성된 클링커가 합성가능하다. Alunite was dehydrated at 500~$580^{\circ}C$ and desulfurued at 580~$780^{\circ}C$ in air atmosphere. Therefore, this study was carried out to investigate the formation conditions of anhydrite ($CaCO_4$) when the mixtures of alunite $[K_2SO_4$.$Al_2(SO_4)_3$.$4Al(OH)_3$] and limestone ($CaCO_3$)were roasted. Alunite scarcely dected the partial pressures of $CO_2$(g), but limestone was bansformed into CaO at $650^{\circ}C$ in air and $900^{\circ}C$ in saturated $CO_2$(g), atmosphere, respectively. When the the mixtures of 1 mol of alunite and 6 rnol of limestone were roasted for 2 hours at lO00C in air and saturated $CO_2$(g), anhydrite was formed at $550^{\circ}C$ calciumlangbeinite, at $700^{\circ}C$and haiiyne, at 800~$950^{\circ}C$. The formation rate of anhydrite in air and saturated $CO_2$(g), was 99.0 % and 95.0 %, respectively. then the formation rate of anhydrite was not changed in air atmosphere but increased according to the decreasing of the particle size of limestone in saturated $CO_2$(g). Therefore, when the mixture of 1 mol of alunite and 6 rnol of limestone were roasted, the clinker composed of lmol of haiiync and 1 mol of calciumlangbeiilte can be manufactured

Mobile WiMAX에서 IPTV 및 VoIP 음성서비스 품질을 고려한 수면구간 길이와 지터버퍼 크기의 상관관계 분석

김형석,김태현,황호영,Kim, Hyung-Suk,Kim, Tae-Hyoun,Hwang, Ho-Young 한국정보처리학회 2010 정보처리학회논문지 C : 정보통신,정보보안 Vol.17 No.3

IPTV 및 VoIP 서비스는 높은 이동성과 전송 속도를 보장하는 Mobile WiMAX 네트워크 상에서 제공할 수 있는 유용한 응용 서비스들이다. IPTV의 오디오 전송이나 VoIP의 통화 품질에 영향을 미치는 요소 중 전송 경로의 잦은 변경이나 경로간 전송 시간의 차이에 따라 발생하는 지터에 의한 패킷 손실은 지터 버퍼를 이용하여 완화할 수 있다. 본 논문에서는 Mobile WiMAX 네트워크 상에서 이동 단말의 전력 소모 절감을 위해 사용되는 PSC-II 모드를 사용할 때의 오디오 및 음성 서비스의 품질(Quality of Service)과 지터 버퍼 크기의 상관관계에 대해 연구, 분석한다. 이를 위해 절전 모드 사용으로 인해 추가로 발생하는 지연 시간을 포함한 서비스의 종단간 지연시간 모델과 종단간 지연시간을 기준으로 한 서비스 품질 기준을 제시하였다. 또한, 제시한 모델의 다양한 파라미터에 따른 시뮬레이션 분석 결과를 통해 절전 모드를 사용할 경우에는 지터 버퍼의 크기 증가에 따른 지연으로 인한 패킷 손실이 오히려 오디오 및 VoIP 서비스 품질 측면에서 좋지 않은 영향을 미칠 수 있음을 보였다. IPTV and VoIP services are considered as killer applications over Mobile WiMAX network, which provideshigh mobility and data rate. Among those which affect the quality of voice in those services, the jitter buffer or playout buffer can compensate the poor voice quality caused by the packet drop due to frequent route change or differences among routes between service endpoints. In this paper, we analyze the correlation between the sleep interval length and jitter buffer size in order to guarantee a predefined level of voice quality. For this purpose, we present an end-to-end delay model considering additional delay incurred by the WiMAX PSC-II sleep mode and a VoIP service quality requirement based on the delay constraints. Through extensive simulation experiments, we also show that the increase of jitter buffer size may degrade the voice quality since it can introduce additional packet drop in the jitter buffer under WiMAX power saving mode.