단일전극을 가진 마이크로 가스센서의 제작 및 특성

송갑득,박영일,이상문,이윤수,최낙진,주병수,서무교,허증수,이덕동 한국센서학회 2002 센서학회지 Vol.11 No.6

센서의 안정도와 감도를 개선시킬 수 있는 단일전극을 가진 열선형 마이크로 가스센서를 제작하였다. 일반적으로, 금속산화물 반도체를 이용한 가스센서는 히터전극과 감지전극의 두 개의 전극을 가지고 있다. 제작된 센서는 히터전극위에 감지물질을 형성하여 단일 전극을 가지는 구조를 가지고 있다. 히터와 감지전극으로 사용되는 Pt는 glass 기판위에 스퍼터링법으로 형성하였으며, SnO_2 감지물질은 제작된 Pt 전극위에 열증착시켜 형성하였다. SnO_2막은 lift-off 공정을 이용해서 패턴을 형성하고 1시간 동안 산소분위기에서 열산화하였다. 제작된 소자의 크기는 1.92x.1 mm^2 이다. CO 가스에 대한 감지특성을 조사한 결과 1,000 ppm에 대해 100 mV의 출력변화를 나타내었으며, 넓은 농도범위(0 ~ 10,000 ppm에서 선형적인 전압출력을 나타내었다. 또한 가스 반응 전과 반응 후의 전압출력을 비교해 볼 때, 1 % 이내의 편차를 나타내는 우수한 회복성을 나타내었다. Micro gas sensor with single electrode was proposed for improving stability and sensitivity, Generally, metal oxide gas sensors have two electrodes for heating and sensing. This fabricated new type sensor have only a single electrode by forming a sensing material onto heating electrode. Pt as a heating and sensing electrode was sputtered on glass and a SnO_2 sensing material was thermally evaporated on Pt electrode. SnO_2 was patterned by lift-off process and then thermally oxidized in O_2 condition for 1 hr., 600 ℃. The size fabricated sensor was 1.9 x 2.1 mm^2. As a result of CO gas sensing characteristics, this sensor showed 100 mV change for 1,000 ppm and linearlity for wide range(0 ~ 10,000 ppm) of gas concentrations. And the sensor shows a good recovery characteristics of 1 % deviation compared to initial resistance.

리티움 이온 고체전해질 CO₂센서

송갑득,서무교,곽종식,이덕동 경북대학교 센서기술연구소 1995 센서技術學術大會論文集 Vol.6 No.1

Carbon dioxide gas sensor, which has inner heater, is fabricated using Li ionic electrolyte as raw material which is systhesized by sol-gel method. It has either Au electrode or Pt electrode as the metal electrode of sensing electrode part. Sensing characteristics for carbon dioxide gas and interference effect for carbon monoxide gas and hydro carbon gases are investigated. The sensors using Au electrode and Pt electrode show sensitivity about 25 mV/decade and 26 mV/decade for the variation of carbon dioxide gas concentration, respectively. The sensor using Au electrode shows more exellent selectivity compared to that using Pt electrode for carbon monoxide gas and hydro carbon gases.

고체전해질형 CO₂가스 감지 소자의 제작 및 그 동작 특성

서무교,송갑득,곽종식,이덕동 경북대학교 센서기술연구소 1994 센서技術學術大會論文集 Vol.5 No.1

The raw material of solid electrolyte type CO_(2) sensor was synthesized using tetraethoxysilane, lithium methoxide, zirconium n-propoxide, and tributyle phosphate as precursors, this process was carried out at 60℃ in N_(2) ambience. The prepared material was dried and crushed into powder, and it was pressed into disk type samples. These samples were sintered at 9000 -1100℃ for 50 hours. The physical characteristics of the samples were investigated by TG/DTA, SEM and XRD. The solid electrolyte type CO_(2) sensor was fabricated and its operational characteristics were measured. The sensing characteristics of the sensor shows about 86 mV/decade for the variation of CO_(2) concentration.

리튬 이온 전도체를 이용한 히터가 내장된 CO₂센서

채유석,송갑득,강봉휘,서무교,이덕동 경북대학교 센서기술연구소 1997 센서技術學術大會論文集 Vol.8 No.1

The simple solid electrolyte carbon dioxide sensor was fabricated using Li ionic conductor with a heater and Li_(2)CO_(3)+Na_(2)CO_(3)+K_(2)CO_(3) (47.6 : 25.4 : 27.0) as a metal carbonate auxiliary phase. The electromotive force(EMF) was in excellent agreement with the EMF value calculated from the Nernst' s equation for CO_(2) gas concentration from 950 to 9,950ppm at 420℃, with the response time of 15~25 sec.. Water vapor hardly affected the sensor characteristics for relative humidity from 40% to 90%, in contrast to the case of the Li_(2)CO_(3) and Na_(2)CO_(3) + BaCO_(3)(1 : 1.7). The CO_(2) sensitivity of this sensor was stable for the test period of 240 hours.

그레이브스병 환자에게서 항갑상선제 투여 후 발생한 무과립구증 1 예 및 10 년 간의 증례 고찰

송영수,임승길,허갑범,이현철,김경래,송영득,차봉수,강신명,박정수,안철우,장항석,정웅윤 대한내과학회 2001 대한내과학회지 Vol.60 No.4

Since introduce of antithyroid drugs (ATDs) in 1941, they have been widely used for treatment of Graves' disease and other hyperthyroid disorders. However, agranulocytosis, the most serious adverse effect of ATD treatment, has been occasionally reported. Agranulocytosis should be diagnosed and be treated promptly due to possible fatality. We have experienced a 17 year-old girl with PTU (propylthiouracil)- induced agranulocytosis. Initial graulocyte count was 400/㎣, and presenting symtoms were fever and sore throat. She has recovered from agranulocytosis without complications after use of G-CSF (granulocyte-colony stimulating fact or). We reviewed and analyzed additional 7 cases of ATD-induced agranulocytosis in Yonsei University Hospital (From 1988 to 1998). We found that ATD-induced agranulocytosis, of which incidence is known to be ranged from 0.1 to 1 percent , does not seem to have a distinct correlation with sex, age, dosage, and the kind of ATD. Event of agranulocytosis has a tendency to occur within3 months, and in a few case it has been occasionally detected in asymptomatic patients, routine monitoring of the white blood cell count within 3 months after the start of ATD medication can be helpful in predicting and in detecting agranulocytosis. The treatment of ATD-induced agranulocytosis has been mainly composed of conservative care, but according t o introduction and popular application of G- CSF, the use of G-CSF seems to be a promise of a reduction in morbidity and mortality.(Korean J Med 60:398- 403, 2001)

발병연령에 따른 두개인두종의 합병증 및 예후

송건훈,이지현,허갑범,이현철,임승길,이은직,김경래,송영득,남문석,차봉수 대한내분비학회 1995 Endocrinology and metabolism Vol.10 No.3

Craniopharyngioma is the most common tumor involving the hypothalamo-pituitary area in childhood and adolescence. Recently, we carried out collective review of 70 patients with craniopharyngioma treated from January 1980 to December 1994 in order to inverstigate the endocrine outcome and survival according to the age of onset. The following results were obtained: 1) The male to female ratio was 1:1. Age at diagnosis ranged from 2 to 64 years(mean age: 23) with the greatest frequency in the 2nd decade of life(28.6%). Of the 70 cases, the first group, 27 cases were under the age of 15, and the other group, 43 cases were over 15 year-old. 2) The most common symptom at diagnosis in both groups was headache. In the adult group, symptoms related to hypogonadism(amenorrhea, decreased libido, galactorrhea etc.) were not uncommon. The lag of time between onset of symptom and hospital visit ranged from 3 days to 156 months(mean: 20 months). 3) The main site of tumor was suprasellar region in both groups. The most common CT finding in both groups was calcification in sella turcica. 4) In pre-operative combined pituitary function test, the most common, abnormal responses were shown in growth hormone and thyroid stimulating hormone in both groups. In addition, prolactin frequently showed abnormal response in the adult group.In post-operative combined pituitary function test, more hormones tended to reveal abnormal response in the group treated with surgery plus radiation therapy. 5) The operation by subtotal removal followed by radiation therapy was the most commonly used method in treatment of both groups. After treatment, panhypopituitarism was occurred more frequently in the group treated with RT after surgery than those treated with surgery alone, but the difference was not statistically significant(p=0.136 in childhood, 0.436 in adults). Except the cases with panhypopituitarism, the most commonly encountered endocrine abnormalities were growth retardation in the children group, and hypogonadism in adult. The recurrence was clinically observed in 11 cases. The recurrence rate were 11.1% in children, and 18.6% in adult respectively. The mean time from the initial treatment to recurrence was 23 months. There was no significant difference in recurrence rate between the group treated with RT after subtotal removal and the group treated with total removal(p=0.475). The overall five-year survival rate after treatment was 82.8%. According to the treatment modalities, the patients undergone RT after subtotal removal survived much longer than those treated with other modalities such as subtotal removal only or total removal, but the differences in survival were not statistically significant(Log rank test, p=0.0539)(J Kor Soc Endocrinol 10: 262-272, 1995).

폐와 위장의 전이성 석회화를 동반한 부갑상선 선종 1 예

송건훈,이지현,허갑범,이현철,임승길,송영득,남문석,차봉수,변영섭 대한내과학회 1996 대한내과학회지 Vol.51 No.3

Metastatic calcification of soft tissues due to hypercalcemia is a well-recognized complication of various malignancies and renal failure. It results from metabolic derangement in which calcium salts are deposited in otherwise normal tissuel. The calcific process principally affects lungs, stomach, kidneys and other soft tissues. With advance of nuclear imaging modalities, metastatic calcification can be detected earlier so that appropriate therapy may be instituted. A case of parathyroid adenoma with metastatic pulmonary and gastric calcification is presented. She showed intense concentrations of bone-seeking radionuclide( ^(99m)Technetium) in both lungs and stomach on routine bone scan. Renal function of the patient was moderately impaired, Right inferior parathyroidectomy was performed. Her serum calcium concentration decreased postoperatively and had to be maintained with orally administered calcium and aldactazide. After the operation the clinical course has been uneventful. Follow-up bone scan performed lo days following the operation revealed persistence of lung uptake despite restoration of normal blood calcium concentration, but disappearance of gastric uptake. So we report the case of parathyroid adenoma complicating metastatic pulmonary and gastric calcification with review of literature.

리티움 이온 전도체를 이용한 CO2 센서의 제조 및 그 특성

이덕동,서무교,송갑득 경북대학교 전자기술연구소 1996 電子技術硏究誌 Vol.17 No.1

Carbon dioxide gas sensor, which has inner heater, was fabricated using Li ionic conductor as raw material which was synthesized by sol-gel method. It had either Au electrode or Pt electrode as the metal electrode of sensing electrode part, and carbonate mixture was used as sensing electrode material of low operating temperature about 250℃. Sensing characteristics to carbon dioxide gas, and interference to carbon monoxide gas and hydro carbon gases were investigated. The sensor using Au electrode showed the sensitivity of 25 ㎽/decade and the sensor using Pt electrode showed the sensitivity of 26 ㎽/decade for the variation of carbon dioxide gas concentration, respectively. The sensor using Au electrode showed good selectivity compared to that using Pt electrode for carbon monoxide gas and hydro carbon gases. From the above results, the CO₂ sensor with Au electrode is very useful to measuring the CO₂ concentration.

건강한 젊은 남성에 있어서 인슐린 저항성과 관련인자에 관한 연구

허갑범,이현철,송영득,정윤석,차봉수,박석원,윤용석 대한당뇨병학회 1998 Diabetes and Metabolism Journal Vol.22 No.4

Tumor Necrosis Factor - alpha 가 돼지 간 및 신장의 절편 및 추출액에서의 T4 로부터 T3 로의 말초전환에 미치는 영향

허갑범,이현철,임승길,이은직,김경래,송영득,남문석,남수연,조재화 대한내분비학회 1995 Endocrinology and metabolism Vol.10 No.3

Abnormal thyroid function is seen in a wide variety of patients with acute and chronic nonthyroidal-illness, consisting of reduction in both thyroid function and peripheral T_4 to T_3 conversion including decreased serum thyroxin(T_4), decreased triiodothyronine and normal or slightly increased serum TSH. Recently increasing awareness of the role tumor necrosis factor-alpha(TNF-alpha) in systemic illness led us to consider a possible contribution of TNF-alpha to thyroid dysfunction in this setting. So we hypothesized that TNF-alpha might affect peripheral conversion of T_4 to T_3. We, therefore, explored the effects of TNF-alpha in slices and extracts of porcine liver and kidney. Thyroxine(T_4, 5ug/ml) was incubated in 0.15M phosphate buffer(PH 7.4) with slices(approximately 0.3 g-equivalent of tissue) and extracts(approximately 0.23 g-equivalent of tissue) of porcine liver and kidney with various concentrations(0-500pg/ml) of recombinant human TNF-alpha for 2 hours at 37 degree, and the T_3 generated during incubation was measured by radioimmunoassay of an ethanol extracts of the extracts and the homogenates of the slices. The slices produced more T_3 than extracts and the kidney was more active than the liver. TNF-alpha inhibited T_4 to T_3 conversion in dose-dependent manner in slices and extracts of porcine liver and kidney. Our data suggest that TNF-alpha have inhibitory effect of T_4 to T_3 conversion in liver and kidney(J Kor Soc Endocrinol 10: 242-248, 1995).