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.

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.

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.

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.

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.

과학정신의 생활화(상)

김형석,Kim, Hyeong-Seok 한국과학기술단체총연합회 1976 과학과 기술 Vol.9 No.11

소음(騷音) Stress에 의한 요(尿)중 Catecholamine의 분비량(分泌量) 변화(變化)

김형석,전준배,Kim, Hyung-Suk,Chun, Joon-Bae,Lundberg, Ulf 대한예방의학회 1993 Journal of Preventive Medicine and Public Health Vol.26 No.4

Noise is not only affecting the ear and the auditory cortex locally, but its influence is widely spread throughout the brain structures, e. g., the reticular formation, the brain stem nuclei or the subcortical forebrain area. Hence, any of the organism's activities can be hindered or stimulated by noise. High noise is a stressor and the catecholamine level can be used both as a stress marker and as an indicator of modified sympathetic nervous system activity. Several recent studies have found that the urinary excretion of catecholamines is increased due to high noise intensity, especially unexpectedly high and long lasting noise. The present study was conducted in order to examine the effects of noise stress on urinary excretion of ctecholamines in rats and humans. Rats were exposed to 90 dB noise for 10, 30, and 60 minutes, 3 and 12 hours. 24 hour . urinary samples were collected and the catecholamones were extracted by alumina and analyzed by HPLC-ECD. Catecholamine levels increased with time of exposure up to 60 minutes : norepinephrine concentration at 60 min of noise=1.038 ng/ml, epinephrine=0.636 ng/ml. Urine catecholamines of blue collar workers exposed to 90 dB of noise at the work place were collected between 2 and 4 p.m. and compared to that of white collar workers exposed to 70 dB. Mean norepinephrine level of the blue collar workers was 0.89 ng/ml (${\pm}0.25$), epinephrine 0.24ng/m1 (${\pm}0.09$), and that of the white collar workers 0.48 ng/ml (${\pm}0.12$), epinephrine 0.19 ng/ml(${\pm}0.05$). It was concluded that noise acts as a stressor and increases the catecholamine levels in both rats and humans.

척수 압박을 동반한 제 3 요추의 골연골종 - 1례 보고 -

김형석,홍기도,하성식,이선우,Kim, Hyung-Seok,Hong, Ki-Do,Ha, Sung-Sik,Lee, Sun-Woo 대한근골격종양학회 1997 대한골관절종양학회지 Vol.3 No.1

본 서울위생병원 정형외과에서는 제 3 요추의 좌측 추궁판과 하 관절 돌기에서 발생하여 척수 압박 증상을 일으킨 골연골종 1례를 경험하였기에 문헌고찰과 함께 보고하는 바이다. One of the most common benign tumors of bone is the osteochondroma which is a cartilage-capped bony projection on the surface of a bone. It may occur in any bone that has been performed from cartilage, but the most common locations are the long bone at the metaphyseal region of the most active growth cartilage, that is, the lower end of femur, the upper end of the tibia, and the upper end of the humerus. Other bones often involved are the ilium, scapula, fibula, and phalanges of hands and feet. But, the vertebral column is very rare location for osteochondroma. Only one case of osteochondroma involving the lumbar spine has been previously reported in Korea. We report an unusual case of osteochondroma arising from the left lamina and inferior articular process of the 3rd lumbar spine causing spinal cord compression.

단부에 국부부식이 발생한 용접 원형 강관의 잔존 압축 강도 평가

김형석,신창희,다오두이킨,정영수,김인태,Kim, Hyoung Seok,Shin, Chang Hee,Dao, Duy Kien,Jeong, Young Soo,Kim, In Tae 한국강구조학회 2018 韓國鋼構造學會 論文集 Vol.30 No.3

본 연구에서는 연결부나 지점부 등 단부에 국부부식이 발생한 원형강관의 압축강도 평가법을 검토하기 위해, 단부에 인위적인 국부부식을 모사한 용접 원형강관의 압축실험을 실시하였다. 원형강관 시험체는 단주로 제작하였으며, 부식환경에 따른 다양한 국부부식 정도를 모사하기 위해 부식된 깊이를 0, 4, 6 mm로, 부식된 높이를 0, 20, 60, 180 mm로 기계 가공하였다. 압축실험 결과, 압축 임계하중은 부식된 깊이 및 높이가 증가함에 따라 선형적으로 감소하였으며, 잔존 임계하중비는 부식손상 부피비로 추정할 수 있음을 확인하였다. 또한, 국부부식 손상 부피비를 이용하여 단부에 부식손상이 발생한 용접 원형강관 단주의 잔존 압축 임계하중 평가식을 제시하였다. To investigate compressive strength of corroded circular tubular columns, compression tests were carried out on welded circular tubular members with locally corroded end. The members were cut into short columns and artificial local corrosion were introduced to the bottom end with different corrosion depth of 0, 4, 6mm and height of 0, 20, 60, 180mm. As a result, compressive critical loads decreased linearly with increasing of corrosion level (depth and height), and it was confirmed that residual compressive critical loads can be evaluated by corroded volume loss ratio. Accordingly, an equation of residual compressive critical loads was suggested for welded circular tubular short columns with locally corroded ends.