• Childhood Kidney Diseases
• /
• 제2권2호
• /
• pp.178-182
• /
• 1998

목 적 : 폐색성 요로질환의 진단방법 중 하나인 Whitaker 검사는,소아에서 신우내 관류액의 주입속도를 일반적으로 5mL/min로 시행한다. 그러나 이러한 속도는 생리적이지 못할 뿐 아니라 급속한 신우내 압력의 상승으로 요일출, 신내역류 등의 합병증을 초래할 수 있다. 이에 저자들은 소아 Whitaker 검사사, 보다 낮은 관류속도에서 어떠한 신우내 압력의 변화가 오는가를 관찰하고 적절한 관류속도를 평가하고자 하였다. 방 법 : 이뇨성 신주사로 요로폐색의 진단이 모호했던 3명의 편측 수신증 환아를 대상으로 Whitaker검사를 시행하였으며, 이때 신우내 관류속도를 1 mL/min로부터 시작하여 폐색의 진단기준인 신우내 압력이 $22\;cmH_2O$ 이상이 쥘 때까지 서서히 증가시켰다. 결 과 : 1례에서는 2 mL/min의 관류속도에서 신우내압력이 $50\;cmH_2O$까지 상승하였고 다른 2례에서도 3 mL/min에서 양성의 결과를 얻을 수 있었다. 한편 검사 중, 요일출 등의 부작용은 발생하지 않았다. 결 론 : 소아 Whitaker검사시 관류속도를 획일적으로 5mL/min로 시행하기보다는 1 mL/min로부터 서서히 속도를 증가시킴으로써 요로폐색의 진단을 내릴 수 있을뿐더러, 검사의 합병증을 예방할 수 있을 것으로 사료된다.

• 한국지반환경공학회 논문집
• /
• 제15권5호
• /
• pp.67-74
• /
• 2014

본 연구에서는 점토의 액성한계에 따른 압밀특성을 연구하기 위하여 일정한 압력으로 예압밀 된 재성형 점토를 이용하여 표준압밀시험과 일정변형률 압밀시험을 수행하였다. 압밀시료들은 카올리나이트에 중량대비 6 %, 9 %, 12 %, 15 %의 벤토나이트를 혼합하여 제작하였으며, 시료들의 액성한계시험을 수행한 결과 각각 77 %, 84 %, 88 %, 91 %의 값을 얻을 수 있었다. 또한 액성한계의 약 2배의 증류수를 첨가 후 충분히 교반하여 0.2 MPa의 일정한 압력조건하에 예압밀시켜 제작하였다. 최근 일반적으로 사용되고 있는 표준압밀시험과 ASTM, D4186-82에 따라 변형률 속도를 0.001 %/min, 0.004 %/min, 0.01 %/min을 적용하여 일정변형률 압밀시험을 수행하고 선행압밀하중을 0.2 MPa의 예압밀압력에 대해서 비교 분석하였다. 그 결과 액성한계가 낮을수록 빠른 변형률 속도에서 선행압밀하중이 예압밀압력과 유사하게 나타났으며, 액성한계가 높을수록 느린 변형률 속도에서 선행압밀하중이 예압밀압력과 유사하게 나타났다.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2009년도 춘계학술대회 논문집
• /
• pp.37-40
• /
• 2009

본 연구에서는 케로신/과산화수소 점화용 분사기의 설계/제작하여 분무특성에 관한 연구를 수행하고자 하였으며, 이에 앞서 촉매점화방식으로 적용할 때 가장 적합한 분사기를 설계하고자 하였다. 설계/제작된 분사기를 수류시험을 통해 질량 유량 및 분산각을 측정하였다. 그 결과 케로신의 목표 질량유량(12.88 g/s)은 설계 차압과 같은 차압인 3 bar에서 측정되었으며, 이 때 분산각은 $40^{\circ}$을 확인하였다. 또한 과산화수소의 목표 질량 유량(94.39 g/s)은 설계 차압(3 bar) 보다 작은 1 bar에서 측정됨을 확인하였다.

• 대한기계학회논문집A
• /
• 제23권11호
• /
• pp.1886-1895
• /
• 1999

The delamination behavior of multidirectional carbon-fiber/epoxy composite laminates under 10NA intermediate and high rates of test, up to rate of about 11.4m s has been investigated using the double cantilever beam specimens. The mode I loading under rates above l.0m/s showed considerable dynamic effects on the load-time curves and thus higher values of the average crack velocity than that expected from a simple proportional relationship with the test rate. The modified beam analysis utilizing only the opening displacement and crack length exhibited an effective means for evaluating the dynamic fracture energy $G_{IC}$. Based on the assumption of constant flexural modulus, values of $G_{IC}$ at the crack initiation and arrest were decreased with an increase of the test rate up to 5.7m/s, but the maximum $G_{IC}$ was increased at 11.4m/s.

• 한국동물위생학회지
• /
• 제21권3호
• /
• pp.255-260
• /
• 1998

Since bovine leukosis caused considerable economic loss to the dairy industry, seroepidemiologi-cal survey on bovine leukosis was carried out for the dairy herds in Kyunggi province. 1. When compared the results of immunodifussion test with those of enzyme-linked immunosorbent assay(ELISA) for 94 dairy herds sera, the relationship between the immunodifussion test and ELISA were showen high corresponding rate with sensitivity(97.5%) and specificity(92.6%). 2. In immunodiffusion test for bovine leukosis virus (BLV) antibody in 570 dairy cattle from 30 herds, mean positive rate for BLV antibody was 28.2%. The positive rate by districts were 16.5% in central, 35.4% in east, 17.3% in west, 29.1% in south, 31.6% in north, 43.7% in northeast. 3. When the results of serological studies was analyzed by age groups, the number of positive was increased gradually with the advanced in age of herds. The highest positive rate was found in the age over 6 years. 4. Of 30 dairy herds examined, 5 herds(16.7%) have no reactions against BLV antigen while 15 herds (50%) showed the range of 1∼5 positive cattle and 5 herds(16.7%), the rang of over 11 positive cattle.

• 한국지반공학회논문집
• /
• 제26권1호
• /
• pp.55-62
• /
• 2010

진동타입기에 의해 시공되는 강널말뚝의 관입속도를 예측하고자 수정 Ramberg-Osgood 모델을 적용하여 진동타입기의 주기운동에 따른 지반의 동적 저항력을 모사하고자 하였다. 수정 Ramberg-Osgood 모델을 규정짓는 다양한 인자는 현장시험을 통해 구한 동적 지반저항력곡선의 양상을 반영하여 결정하였는데 이때 매개변수로는 표준관입시험값(N값)을 이용하였다. 관입속도는 해석결과가 현장시험결과에 비해 작게 계산되었으며 관입깊이에 따른 관입 소요시간은 해석결과가 현장시험결과에 비해 크게 계산되어 해석결과가 현장시험결과에 비해 보수적인 값을 보여주었다.

• 대한전자공학회:학술대회논문집
• /
• 대한전자공학회 2000년도 하계종합학술대회 논문집(4)
• /
• pp.92-97
• /
• 2000

An AMR(Adaptive Multi-Rate) speech coding algorithm has been adopted as a standard speech codec for IMT-2000. It is based on the algebraic CELP, and consists of eight speech coding modes having the bit rate from 4.75 kbit/s to 12.2 kbit/s. It also contains the VAD(Voice Activity Detector), SCR (Source Controlled Rate) operation, and error concealment scheme for robustness in a radio channel. The bit rate of AMR is changed on a frame basis depending on the channel condition. In this paper, we introduced AMR speech coding algorithm and performed the real-time implementation using TMS320C6201, i.e., a Texas Instrument's fixed-point DSP. With the ANSI C source code released from ETSI and 3GPP, we convert and optimize the program to make it run in real time using the C compiler and assembly language. It is verified that the decoded result of the implemented speech codec on the DSP is identical with the PC simulation result using ANSI C code for test sequences. Also, actual sound input/output test using microphone and speaker demonstrates its proper real-time operation without distortions or delays.

• 대한기계학회논문집
• /
• 제17권9호
• /
• pp.2381-2389
• /
• 1993

In this paper the design and test results of a dynamic flow rate sensor was reported. This sensor comprises an 2-way cartridge valve as standard hydraulic component and a displacement sensor. Its working principle bases on the linear relationship between the flow rate and the piston displacement of 2-way cartridge valves under constant pressure drop. This principle is well known, however it is not easy to develop a flow rate sensor with the measurement range of 300 1/min, pressure loss of less than 8 bar at 300 1/min, maximum linearity error of less than $\pm$1% and the maximum rising time of 10 ms. This paper describes the design procedure of the flow rate sensor, the improvement procedure of static performance and test method and results of dynamic performance.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2001년도 봄 학술발표회 논문집
• /
• pp.239-244
• /
• 2001

Natural clayey soils or improved grounds are in a overconsolidated conditions due to changes in vertical stress and pore pressures, desiccation, ageing and so on. These grounds show inelastic stress-strain behaviour characteristics within all range of strain except very small strain (${\gamma}$$\_$s/$\leq$10￣$^3$∼10￣$^4$%) when construction, such as excavations and retaining walls, is performed. Also it strongly depends on loading rate of current stress path and recent stress path. This study carried out drained stress path tests by varying loading rate of current and recent stress path. Test results indicated that stress-strain behaviour of overconsolidated clay depends on loading rate, especially loading rate of current stress path.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 2008년도 추계 학술발표회
• /
• pp.1181-1192
• /
• 2008

A laboratory investigation was carried out into effects of strain rate on undrained shear behavior of Holocene clay underneath Kobe Airport with an objective to evaluate the factor of safety of the retaining structure built on it. It was examined in a series of triaxial compression and extension tests performed using different rate of axial straining. A comparative compression test in which the strain rate was changed in steps was also carried out. Similar tests were performed in constant-volume direct shear box (DSB) test. And, the deformation characteristics of the clay were also examined in order to evaluate the variation of stiffness during undrained shearing. It was found that the undrained strength increased with not only the shear rate but also the consolidation period. ISOTACH properties seemed a key to govern the undrained shear behavior.