요추간판탈출증에서 현미경 수술과 경피적 자동수핵제거술에 대한 비교연구

신원한,장재칠,주교성,김범태,최순관,변박장 순천향의학연구소 1997 Journal of Soonchunhyang Medical Science Vol.3 No.1

A retrospective study of operative results were carried out in a series of 164 patients who were performed microdiscectomy and 57 patients performed automated percutaneous lumbar discectomy (APLD) for herniated lumbar discs between January 1, 1990 and June 30, 1996 at the Department of Neurosurgery, Soonchunhyang University Hospital. The operative results were analysed, and the correlation between preoperative clinicoradiological factors and postoperative clinical results were statistically assessed. The major results were as follows : 1. Of 164 microdiscectomy cases, 102 were males and 62 were females, mean age was 42.4 years and incidence was the highest in the 5th decade, and of 57 APLD cases, 43 were male and 14 female, mean age was 32.2 years and incidence was the highest in the 3rd decade. 2. The preoperative symptoms and signs were lumbago(98.2%), radiating pain(96.3%), positive straight leg raising test(77.4%), motor weakness(27.4%), claudication(13.4%) & voiding difficulty(2.4%) in microdiscectomy cases, and lumbago(98.2%), radiating pain(98.2%), positive straight leg raising test(70.2%) & motor weakness(17.5%) in APLD cases. 3. Number of operated levels were performed 226 in microdiscectomy and 74 in APLD. The most commonly operated levels of two groups were L4-5 level. 4. Operative results 1) The overall success rates by Prolo's scale were 87.1% in microdiscectomy and 80.7% in APLD, respectively. 2) In younger age group (below 30 years) and in non-compensatory group, success rates were significantly higher in microdiscectomy. 3) As to protrusion and degeneration on MRI, clinical results of moderate protrusion and degeneration of discs in microdiscectomy were statistically significant, and those of mild protrusion and degeneration of discs in APLD were also statistically significant. 4) The most common cause of failure was inappropriate removal of disc material in microdiscectomy and sequestered discs in APLD. According to the above results, there were no differance in overall success rates between microdiscectomy and APLD. But clinical results seem to be influenced by the age, existence of compensation, and by the degree of protrusion and degeneration of discs as prognostic factors. If the selection of operative procedure between microdiscectomy and APLD for herniated lumbar disc is carefully done with clinical and radiologic findings of patients, good outcome might be achieved.

쵸퍼시스템의 傳達特性에 관한 硏究

任漢錫,金洛敎 건국대학교 부설 산업기술연구소 1982 논문집 Vol.7 No.-

Chopper system has been recently employed in variable-speed DC motor drives by the manner in which the average load voltage is reduced below that of the source. The output current can be continuous or discontinuous during the operation period. When the load current becomes discontinuous, the output gain is greatly reduced and this would result in sluggish response and poor accuracy at light loads. Hence, in this paper, the transfer characteristics of a chopper system is to be investigated and the method is studied to compensate the reduction of gain.

개별요소법을 이용한 불연속 암반내 지하공동의 변형 거동 해석

정완교,임한욱 강원대학교 산업기술연구소 2003 産業技術硏究 Vol.23 No.A

Numerical analysis is important for the design, construction and maintenance of large caverns. The rock mass contains generally discontinuities such as faults, joints and fissures The mechanical behavior and geometric Characteristics of these discontinuities would have a significant impact on the stability of the caverns. In this research the Distinct Element Method(DEM) was used to analyze the structural stability of the large cavern The Barton-Bandis Joint Model (B-B J.M) was used as a constitutive model for the joint In addition. two different cases . 1) analysis with a support system and 2) analysis with no support system, were analyzed to optimize a support system and to investigate reinforcing effects of a support system. The most significant parameters of in-situ stress, JRC of in-situ natural joints. and spatial distribution characteristics of discontinuities were acquired through field investigation. Displacement (horizontal. joint shear), maximum joint opening, maximum and minimum principal stresses, range of relaxed zone, rockbolt axial forces and shotcrete stresses were calculated at each excavation stage. As a result of analysis the calculated values proved to be under the allowable value Rockbolts also proved to be an efficient support measure to control joint shear displacement which had significant effects on extending the relaxed zone. As a consequence. the structural stability of the cavern was assured with an appropriate support system.

국산화 개발한 치과용 저금합금의 시효경화 거동

김교한,권오원,김형일 대한치과기재학회 1997 대한치과재료학회지 Vol.24 No.1

To define the optimum heat treatment temperature and time of the developed three types of low karat gold alloys, hardness test, DTA and x-ray diffraction methods were used. The results were as follows. *The optimum temperature of heat treatment was at 400℃ in K-Ⅰ, K-Ⅱ and K-Ⅲ alloys. *The proper time of age-hardening was 10 minute in K-Ⅰ alloy, and 10-30-minutes in K-Ⅱ alloys. *The stable phases of three types of low karat gold alloys were Ag-rich α₁ phase, Cu-rich α₂ phase and AuCuⅠ phase in case of K-Ⅰ alloy, and α1 phase and AuCuⅠ phase were coexisted in K-Ⅱ and K-Ⅲ alloy. *The cause of the decrease of hardness by overageing was the α₁ phase and AuCu Ⅰ phase, which were precipitated in the grain boundary.

Sandblast 처리한 상아질면의 접착에 관한 연구

김교한,나환욱,황성욱 대한치과기재학회 1997 대한치과재료학회지 Vol.24 No.1

Dentin adhesion was studied on sandblasted dentin with 4-META/MMA-TBB resin. The effect of change of air pressure, with or without pretreatment and primer on tensile bond strength, was mainly investigated. In the effect of air pressure at sandblast treatment, the higher pressure showed the increase of tensile bond strength. The pretreatment with 10-3 sloution after sandblast treatment increased tensile bond strength in the almost conditions. Application of primer also increased the tensile bond strength, confirmed the effect of primer application after sandblast treatment. Alumina particle was not found on the dentin surface in the SEM and EDAX examination.

Sandblast 처리한 상아질면의 접착에 관한 연구

김교한,나환옥,황성욱 경북대학교 의학연구소 2000 경북대학교병원의학연구소논문집 Vol.4 No.1

Dentin adhesion was studied on sandblasted dentin with 4-MET/MMA-TBB resin. The effect of change of air pressure, with or without pretreatment and primer on tensile bond strength, was mainly investigated. In the effect of air pressure at sandblast treatment, the higher pressure showed the increase of tensile bond strength. The pretreatment with 10-3 solution after sandblast treatment increased tensile bond strength in the almost conditions. Application of primer also increased the tensile bond strength, confirmed the effect of primer application after sandblast treatment. Alumina particle was not found on the dentin surface in the SEM and EDAX examination.

치과 임플란트용 순 Ti의 접촉부식 거동

김교한,허만수,김형일,황운석,高田 雄京,奧野 攻 대한치과기재학회 1999 대한치과재료학회지 Vol.26 No.4

One of the fields in which titanium(Ti) is becoming increasingly valuable is the field of biomaterials. Ti had shown its good corrosion resistance, high strength to weight ratio, and compatibility with human tissues. Such applications of Ti in this area involve replacing stainless steel and cobalt-chromium alloy implant which are used in skull, shoulder joint, spine, and dental implant. In dental field, titanium has been used as dental implant, so it becomes necessary to examine and estimate the anti-corrosion ability of Ti and its alloys at the severe conditions such as crevice corrosion and galvanic corrosion. The purposes of this study was to examine the corrosion mechanisms of the pure Ti showing good corrosion resistance under an oral corrosion environment when it is coupled with dental casting Type Ⅱ and Type Ⅳ gold alloys. These coupling corrosion mechanisms were studied in three conditions. First was by measuring the resting potential of pure Ti, when it was uncoupled and coupled with Type Ⅱ and Type Ⅳ alloys. Second was by measuring anode polarization behavior of pure Ti, Type Ⅱ and Type Ⅳ alloys, and third was by detecting dissolved ions from the pure Ti, uncoupled and coupled with Type Ⅱ and Type Ⅳ gold alloys which were immersed in 0.9% NaCl solution for 7 days. The resting potential showed a low potential value at the initial stage but increasing into a high value (to 0.18 V) with time elapse and reached a stable value. On the contrary, the potentials of Type Ⅱ and Type Ⅳ gold alloys were in their values at the initial stage of immersion, then decreased with the time and reached stable values, being higher than the value of pure Ti. When pure Ti coupled with Type Ⅱ and Type Ⅳ gold alloys, the resting potential of coupled one was between the values of each one. When Type Ⅱ and Type Ⅳ gold alloys were coupled with pure Ti, there was an increase in Ag, Cu, and Zn. Also, Zn ions released the high potential precious metal alloys, compared to the uncoupled case. Ti ion was not detected at any cases of pure Ti or coupled with gold alloys. It was thought that one of the causes of the increase in Ag, Zn, and Cu ions when Ti was coupled with dental gold alloys was that Ag, Zn, and Cu ions were selectively dissoluted from the Ag rich regions around grain boundary and the casting defects. In conclusions, the results of this study suggest that the pure Ti was very stable when coupled with the gold alloys in oral cavity.

민산초나무 種實의 油脂 및 蛋白質組成에 관한 硏究

윤한교,김지문 충남대학교 농업과학연구소 1976 農業技術硏究報告 Vol.3 No.2

In order to analyze the composition of fatty acid in the seed oil, and amino acid in the seed protein of wild thornless chinese pepper tree; Zanthoxylum schini folum var. inermis Nakai, GLC method and amino acid autoanalyzer were applied, respectively, while the general composition of the seed and physico-chemical properties of the seed oil were also determined by A. O. A. C. method. The results obtained were summarized as follow The content of oil, protein and ashes were 47.05%, 20.14% and 3.1%, respectively. The content of sulfur and cyan compound in the seed were 0.02% and 0.00005%, respectively, which were far below than allowed guantity by food regulation. Therefore, it is considered to be safe for edible purpose. The iodine absorption number obtained was 145.2, which might be belonged to drying oil. The physico-chemical properties of the seed oil such as acid value, saponification number and refractive index showed the characteristics of an unsaturated high molecular fatty acid compound. The seed oil was composed of 34.8% of oleic acid, 25.1% of linoleic acid and 26.1% of linolenic acid, which accounts for more than 80% of essential fatty acid. Therefore, it could be used as an edible oil. Seventeen kinds of amino acids were anayzed from seed protein. Among them comparatively high content of threonine, valine, methionine, isoleucine, leucine and phenylalanine were observed. As a non-essential amino acid, glutamic acid was found as high as 4.985%. From these results the seed of thornless Chinese pepper would be good for oil and protein source.

Ti표면의 전처리방법이 4-META/MMA-TBB 레진과의 접착강도에 미치는 영향

김교한,서세광 대한치과기재학회 1999 대한치과재료학회지 Vol.26 No.2

The present study investigated the effectiveness of several surface pretreatment methods on the bonding of Ti to adhesive resin. Commercially pure Ti and Ti-6Al-4V alloy were bonded by 4-META/MMA-TBB resin to stainless rods. Each specimen was polished with No. 1.000 sandpaper and then treated with various surface treatment methods, such as 50 ㎛ size of Al₂O₃particles sandblasting, tinplating, silicoating, combination of sandblasting and tinplating and combination of sandblasting and silicoating. The surface of pure Ti treated with sandblasting was roughened to irregular and retentive pattern and aluminum content on the treated surface was increased. The surface morphology treated with tinplating was similar to nontreated one and the surface composition showed almost no change. The surface morphology of silicoating groups was similar to the one of silicoated after sandblasting condition and in both group, carbon content was significantly increased. The surfaces morphology of tinplating was not changed at all. The surface observation results of commercially pure Ti and Ti-6Al-4V alloy specimens were similar, but Ti-6Ai-4V alloy specimens were similar, but Ti-6Al-4V alloy showed more amount of tin precipitations at tinplating groups. Average tensile bond strength of each group was ranged from 21.20 to 31.64 MPa. The tensile bond strength of each group did not show a difference at the 0.05 significance in one-way ANOVA test. Fracture mode of each specimens was almost resin cohesive fracture, and some adhesive fracture-like area was proved to be cohesive fracture in higher magnification. Thus, bonding strength of resin-Ti interface was stronger than that of 4-META/MMA-TBB resin itself.

치과재료와 환경호르몬

김교한 대한치과기재학회 1998 대한치과재료학회지 Vol.25 No.3