온·오프라인 부동산 중개 서비스 품질 개선에 관한 연구

김승범 한국서비스경영학회 2022 한국서비스경영학회 학술대회 Vol.2022 No.11

헬리콥터 꼬리로터 시스템 동적 안정성 시험

김승범,송근웅,김승호,황정선 한국항공우주학회 2011 한국항공우주학회 학술발표회 논문집 Vol.2011 No.11

헬리콥터 꼬리로터 블레이드는 허브, 조종으로부터 회전력과 피치조종력을 전달받아 헬리콥터 요(yaw) 우 축 제어를 위한 추력을 발생시키며, 꼬리로터 허브는 회전에 의한 원심력과 공기력을 감당하고 조종은 비행조종계통에서 구동기를 통해 전달받은 조종력을 이용하여 탄성체 베어링 조립체를 통해 피치각을 제어함으로써 주로터에 의한 토크 상쇄 및 헬리콥터 방향제어에 필요한 꼬리로터 추력을 제어한다. 이러한 헬리콥터 꼬리로터 시스템은 과도한 진동 및 불안정성을 갖지 않도록 동적안정성을 설계 초기부터 고려하고 지상성능시험을 통해 로터안정성을 확인하고 회전시 로터의 동적특성을 파악해야 한다. 본 논문에서는 고흥 항공 센터(KARI) 꼬리로터 훨타워 시험설비를 이용한 꼬리로터 동적안정성 시험에 대해 기술하였다. The helicopter tail rotor system generates the thrust for yaw axis control of the helicopter with the torque and pitch control force transferred from the tail rotor hub/control. The ground whirl test shall be performed to dynamic stability test of tail rotor blade and hub/control according to the airworthiness requirement. Dynamic stability test is performed to rotor dynamic characteristics and should be checked rotor stability at hovering flight. This paper presents the dynamic stability test results of helicopter tail rotor system.

저작권법에 관한 연구

김승범,김영재,김윤진,김정아 이화여자대학교 도서관학과 1987 도서관 학보 Vol.- No.5

상부구조물의 금원주를 레진시멘트로 접착시킨 임프란트 보철물의 파절에 대한 연구

김승범,배정식 전남대학교 치과대학 1995 전남치대논문집 Vol.7 No.1

This study was performed to determine the failure strength and pattern of implant prosthesis luted with resin cement between gold cylinder and superstructure, and to evaluate the bonding strength of resin cement. To evaluate failure strength and pattern, the groups were divided into 2. Group 1 : Casted gold cylinder Group 2 : Luted with resin cement between gold cylinder and superstructure. To evaluate effects of the bond strength of the implant prosthesis luted with resin cement according to storage condition, the groups were divided into 3 ; Group A : Stored in water at 37℃ for 24 hours. Group B : 1000 cycles thermocycled between 5℃ and 55℃ in water. Group C : Stored in water at 37℃ for 30 days. The results were as follows ; 1. Failure was found at gold screw in all specimens of group1 & 2. 2. The bond strength in group 1 and 2 was 189.86 and 188.14Kgf. There was no statistically significant difference between group 1 and 2(P>0.05). 3. The bond strength of group A, B and C was 53.28, 45.86 and 39.29Kgf. There was a statistically significant difference among the bond strength in groups A, B and C(P<0.05). The result suggest the advantage of an improved fit of superstructure to the abutment an a simple procedure. But there was a measurable decrease of the bond strength according to storage conditon. So, Further research is necessary to evaluate the implant prosthesis luted with resin cement between gold cylinder and superstructure.

$BCl_3/Cl_2/Ar$ 고밀도 플라즈마에 의한 $(Ba, Sr)TiO_3$ 박막의 식각 메커니즘 연구

김승범,김창일,Kim, Seung-Bum,Kim, Chang-Il 대한전자공학회 2000 電子工學會論文誌-SD (Semiconductor and devices) Vol.37 No.11

(Ba,Sr)$TiO_3$ 박막은 ULSI-DRAM 즉 1-4 Gbit급 DRAM용 셀(cell) 커패시터의 새로운 유전물질로 각광받고 있다. 본 연구에서는 ICP 장비에서 $BCl_3/Cl_2/Ar$ 플라즈마로 (Ba,Sr)$TiO_3$ 박막을 식각하였다. 이때 RF power/dc bias voltage는 600W/-250V, 반응로의 압력은 10mTorr 이었다. $Cl_2/(Cl_2+Ar)$은 0.2로 고정하였고, $BCl_3$ 가스를 첨가하면서 (Ba,Sr)$TiO_3$ 박막을 식각하였다. $BCl_3$ 가스를 10% 첨가하였을 때, $480{\AA}/min$으로 (Ba,Sr)$TiO_3$ 박막은 가장 높은 식각 속도를 나타내었다. $Cl_2/Ar$가스에 $BCl_3$의 첨가 비에 따른 Cl, BCl 및 B의 라디칼 밀도를 optical emission spectroscopy(OES)에 의해 구하였다. $BCl_3$를 10% 첨가하였을 때 Cl의 라디칼 밀도가 가장 높았다. (Ba,Sr)$TiO_3$ 박막의 표면반응을 규명하기 위하여 XPS 분석을 수행한 결과 이온 bombardment 식각이 Ba-O 결합을 파괴하고 Ba와 Cl의 결합형태인 $BaCl_2$을 제거하기 위하여 필요하다. Sr과 Cl의 결합의 양은 많지 않고, Sr은 주로 물리적인 스퍼터링에 의하여 제거된다. Ti와 Cl은 화학적으로 반응하여 $TiCl_4$ 결합형태로 용이하게 제거된다. 식각후 단면사진을 SEM을 통해 본 결과 식각단면이 약 65~70$^{\circ}$ 정도였다. (Ba,Sr)$TiO_3$ thin films have attracted great interest as new dielectric materials of capacitors for ultra-large-scale integrated dynamic random access memories (ULSI-DRAMs) such as 1 Gbit or 4 Gbit. In this study, inductively coupled $BCl_3/Cl_2/Ar$ plasmas was used to etch (Ba,Sr)$TiO_3$ thin films. RF power/dc bias voltage=600 W/-250 V and chamber pressure was 10 mTorr. The $Cl_2/(Cl_2+Ar)$ was fixed at 0.2 the (Ba,Sr)$TiO_3$ thin films were etched adding $BCl_3$. The highest (Ba,Sr)$TiO_3$ etch rate is $480{\AA}/min$ at 10 % $BCl_3$ to $Cl_2/Ar$. The change of Cl, B radical density measured by optical emission spectroscopy(OES) as a function of $BCl_3$ percentage in $Cl_2/Ar$. The highest Cl radical density was shown at the addition of 10% $BCl_3$ to $Cl_2/Ar$. To study on the surface reaction of (Ba, Sr)$TiO_3$ thin films was investigated by XPS analysis. Ion bombardment etching is necessary to break Ba-O bond and to remove $BaCl_2$. There is a little chemical reaction between Sr and Cl, but Sr is removed by physical sputtering. There is a chemical reaction between Ti and Cl, and $TiCl_4$ is removed with ease. The cross-sectional of (Ba,Sr)$TiO_3$ thin film was investigated by scanning electron microscopy (SEM), the etch slope is about 65~70$^{\circ}$.

Surface Modification of Colloidal Silica by Sulfonation Route for Super - hydrophilicity

김승범,김동표 한국공업화학회 2001 한국공업화학회 연구논문 초록집 Vol.2001 No.1

N/A N/A

램파와 압전소자 극성을 사용한 강구조의 실시간 균열손상 감지기법 개발

김승범,손훈 한국지진공학회 2006 한국지진공학회논문집 Vol.10 No.6

A new methodology of guided wave based nondestructive testing (NDT) is developed to detect crack damage in civil infrastructures such as steel bridges without using prior baseline data. In conventional guided wave based techniques, damage is often identified by comparing the “current” data obtained from a potentially damaged condition of a structure with the “past” baseline data collected at the pristine condition of the structure. However, it has been reported that this type of pattern comparison with the baseline data can lead to increased false alarms due to its susceptibility to varying operational and environmental conditions of the structure. To develop a more robust damage diagnosis technique, a new concept of NDT is conceived so that cracks can be detected without direct comparison with previously obtained baseline data. The proposed NDT technique utilizes the polarization characteristics of the piezoelectric wafers attached on the both sides of the thin metal structure. Crack formation creates Lamb wave mode conversion due to a sudden change in the thickness of the structure. Then, the proposed technique instantly detects the appearance of the crack by extracting this mode conversion from the measured Lamb waves even at the presence of changing operational and environmental conditions. Numerical and experimental results are presented to demonstrate the applicability of the proposed technique to crack detection. 이 연구에서는 강교량과 같은 토목 구조물에서 유도파의(Guided waves) 한 종류인 램파(Lamb wave)를 이용하여 실시간으로 균열손상을 감지할 수 있는 새로운 비파괴 검사방법을 제안한다. 기존의 유도파를 이용한 기술들은, 손상을 감지하기 위해 비손상 상태의 자료를 저장하고 이를 새로이 얻어진 결과와 비교하는 방법을 사용함으로써 잠재적인 손상을 진단해 왔다. 그러나, 공용중인 강구조물은 다양한 하중 뿐 아니라 상시로 변화하는 자연환경에 노출되어 있기 때문에 동일한 비손상 상태의 응답을 얻는 것이 매우 어려우며 이러한 방법을 적용할 경우 오보(false alarm)의 우려도 매우 높다고 할 수 있다. 따라서 이 연구에서는 보다 안정적인 손상감지기법을 개발하기 위해 기존에 얻어진 초기치를 이용하지 않으면서 실시간으로 손상 여부를 판단할 수 있는 방법을 제안하고자 한다. 이 연구에서 제안된 감지 기술은, 압전소자의 극성과 판파의 특성을 이용하는 것으로 얇은 판의 양면에 부착된 압전소자를 통하여 균열손상에 의한 신호를 선택적으로 감지해 내는 데에 그 목적이 있다. 균열이 발생한 판에서 진행하는 판파는 균열로 인한 판의 두께변화로 인해 모드 변화를 일으키게 되는데, 제안된 감지기법으로 이러한 모드 변화만을 선택적으로 추출할 수 있다. 다양한 수치해석과 실험을 통해 이 연구에서 제안된 손상감지기법의 효율성과 적용성을 입증한다.

Rapid Progression of Metastatic Clear Cell Carcinoma in Thoracic Spine: A Case Report

김승범,최혁재,임영진 대한척추신경외과학회 2010 Neurospine Vol.7 No.3

Metastatic spinal cord compression is one of the most dreaded complications of metastatic cancer. This type of compression can lead to pain, neurological deficits and a reduction in the patient's quality of life. A case of rapid progression and exten- sion of a metastatic epidural mass from clear cell adenocarcinoma of the kidney in a short period after surgical decompre- ssion is reported, along with a literature review.

형상 기억 폴리머와 초소수성 표면의 이종 구조를 활용한 프로그래밍 가능한 액적 조작

김승범,김준형,이상엽,김석 대한기계학회 2024 대한기계학회 춘추학술대회 Vol.2024 No.5

Prevalence and Risk Factors of Gastric and Colorectal Cancer after Cholecystectomy

김승범,김경옥,Tae Nyeum Kim 대한의학회 2020 Journal of Korean medical science Vol.35 No.42

Background: Previous studies on the relationship between gastrointestinal (GI) cancer and cholecystectomy remain inconclusive. We aimed to evaluate this relationship, albeit particularly between cholecystectomy and gastric cancer or colorectal cancer (CRC), and the risk factors of cancer among individuals who have undergone cholecystectomy in Korea. Methods: In total, 4,222 patients who underwent laparoscopic or open cholecystectomy at our institution between January 2006 and December 2013 were included. Patients who underwent cholecystectomy for gallbladder cancer or were undergoing surgery for GI, hepatic, or pancreatobiliary cancers were excluded, as were those who developed stomach cancer or CRC within a year of their cholecystectomy. The included patients were followed until July 20, 2020. The standardized incidence ratio (SIR) was used to calculate the relative risk of GI cancer in cholecystectomy patients. Results: The median patient age (n = 3,588) at the time of cholecystectomy was 54.0 (range, 19–95) years, and the male-to-female ratio was 1:1.04. The median follow-up period after cholecystectomy was 15.0 (range, 0–146) months. We found a 108% greater risk of CRC (SIR, 2.08; 95% confidence interval [CI], 1.28–3.17) and 154% increased risk of CRC in females (SIR, 2.54; 95% CI, 1.16–4.84). Based on multivariate analysis, an age of > 60 years was a significant risk factor for GI cancer in cholecystectomy patients. Conclusion: Cholecystectomy may increase risk of CRC, especially in females. Age was considered a risk factor of GI cancers in patients with history of cholecystectomy.