• Proceedings of the Korean Society Of Semiconductor Equipment Technology
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• 2003.12a
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• pp.86-88
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• 2003

Gate 산화막을 high-k 물질인 $HfO_2$ 박막을 이용하여 N-type MOS field effect transistor를 제작하였다. 전극은 poly-Si 전극을 사용하였다. Gate 산화막은 ALD 로 $Hf(N(CH_3)_2)_4$ 원료를 이용하여 $HfO_2$ 박막을 형성하였다. 산화제는 $H_{2}O$ 와 $O_3$ 를 사용하였는데, $H_{2}O$ 가 약간 우수하였으나 그 차이는 크지 않았다. $HfO_2$ 를 증착하기 전에 in-situ 로 $O_3$ 를 흘려 줌으로써 $SiO_2$를 얇게 형성하였는데, 이 결과 threshold voltage 가 약 0.2V 높아지고 saturation current 가 커지는 것이 관찰되었다. 이러한 결과는 $HfO_2$ 박막을 직접 channel 위에 증착하는 것보다 $O_3$ 를 이용 얇은 $SiO_2$ 를 형성하고 그 위에 $HfO_2$ 박막을 증착하는 방법이 transistor의 특성을 향상시키는 데 도움이 된다.

• Geotechnical Engineering
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• v.8 no.3
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• pp.23-36
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• 1992

The flat dilatometer(DMT) has been practically used as an in-situ test equipment. It is a simple, rapid and cost-effective tool to characterize the in-situ stress-strain-strength properties of various types of ground materials. However, the results of flat DMT should be validated with considerable data with respect to the known reference values for a specific site. In this study, the applicability of existing relationships which were established for other local deposits is verified by performing the tests in several clay deposits. To compare with the DMT results, field vane tests and cone penetration tests were also carried out in the same field as reference tests, and unconsolidated undrained tests, oedometer tests, and other fundamental material properties tests were conducted on the thin-walled tube samples in the laboratory. The results of the flat DMT combined with empirical correlations are used to estimate soil types, unit weights, coefficients of lateral earth pressure at rest, overconsolidation ratios, constrained moduli and undrained shear strengths of three clay local deposits. It was found that various geotechnical properties estimated from the flat DMT generally well agree with those from the reference tests.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.4
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• pp.297-308
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• 2007

The granulation equipment of concentrated wastes is manufactured for the polymer solidification of concentrated wastes. It uses liquid sodium silicate as a granulating agent for the granulating of dried powder containing boric acid. The granulating agent is sprayed in the form of droplet and mean size of dried granules is $2{\sim}4mm$. The new technology which has been used for the polymer solidification of spent resin in U.S. and certified by Nuclear Regulatory Commission (NRC) is successfully applied to concentrated wastes. This uses in-situ solidification process within drum without mechanical mixing. Maximum loading of waste can be achieved without increasing of waste volume. Polymer waste forms were evaluated with several test such as fire test, compressive strength test, leaching test, immersion test, irradiation test, and thermal cycling test according to standard test procedures.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.285-289
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• 2017

Laser-induced breakdown spesctroscopy (LIBS) is a technique that complements the disadvantages of conventional laser-based combustion diagnosis techniques such as weak signal strength, complex equipment configuration, and low accuracy. In this study, basic research was carried out to measure the combustion gas temperature of scramjet engines using LIBS. Spray flames were generated from Jet A-1 fuel used in scramjet engines and gas temperatures were measured at the top of the flames with a calibrated thermocouple. The LIBS signals were acquired at the same points as the temperature measurement positions of the thermocouple. The LIBS spectra were analyzed to obtained a calibration curve between the LIBS signal and the reference temperature measured at the thermocouple. Therefore, it was confirmed that the combustion gas temperature can be measured in-situ using LIBS.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.4
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• pp.309-322
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• 2007

This study deals with the irradiation effects on some selected components which are being used in an Advanced Spent Fuel Conditioning Process (ACP). Irradiation test components have a higher priority from the aspect of their reliability because their degradation or failure is able to critically affect the performance of an ACP equipment. Components that we chose for the irradiation tests were the AC servo motor, potentiometer, thermocouples, accelerometer and CCD camera. ACP facility has a number of AC servo motors to move the joints of a manipulator and to operate process equipment. Potentiometers are used for a measurement of several joint angles in a manipulator. Thermocouples are used for a temperature measurement in an electrolytic reduction reactor, a vol-oxidation reactor and a molten salt transfer line. An accelerometer is installed in a slitting machine to forecast an incipient failure during a slitting process. A small CCD camera is used for an in-situ vision monitoring between ACP campaigns. We made use of a gamma-irradiation facility with cobalt-60 source for an irradiation test on the above components because gamma rays from among various radioactive rays are the most significant for electric, electronic and robotic components. Irradiation tests were carried out for enough long time for total doses to be over expected threshold values. Other components except the CCD camera showed a very high radiation hardening characteristic. Characteristic changes at different total doses were investigated and threshold values to warrant at least their performance without a deterioration were evaluated as a result of the irradiation tests.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.35 no.3
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• pp.145-154
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• 2017

In recent years, demand for 1 / 1,000 digital map production has increased in various fields such as construction and urban planning. As a result, the use of low-cost non-metric cameras that replace expensive aerial photogrammetry equipment is required. In Korea, researches are being continuously carried out to produce a large scale digital map by photographing a small target area with a non-metric camera. However, due to the limitation of the accuracy of the non-metric camera, it is difficult to do digital mapping with stereoscopic photographs. In this study, we tried to verify the possibility of large-scale digital mapping to utilize non-metric camera for public survey. For this purpose, the accuracy of the digital mapping results of the non-metric camera and the results of the DMC camera were compared and analyzed. After performing in-situ self-calibration including 8 standard additional parameters, we plotted to a scale of 1/1,000 and confirmed that the RMSE is suitable for public survey accuracy of ${\pm}0.145m$ in horizontal and ${\pm}0.153$ m in vertical.

• Journal of the Korean Geotechnical Society
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• v.30 no.10
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• pp.19-31
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• 2014

In order to investigate ground state change visually in physical model during centrifuge testing, electrical resistivity survey was adopted. Commercial resistivity survey equipment verified at various in-situ sites was utilized. The resistivity survey equipment installed in centrifuge facility was remotely controlled through intranet and electrical resistivity images obtained while centrifuge testing was being checked by real-time inversion. To verify the stable operation of the developed resistivity survey system, preliminary tests were conducted. Model ground was uniformly constructed using unsaturated soil and saline water was dropped on the ground surface to simulate contaminant flow situation. During the 10 g centrifuge tests, electrical resistivity was continuously detected and the testing results were compared with those of identically carried out 1 g centrifuge tests. In addition, the electrical resistivity was directly measured immediately after the centrifuge test by open cutting the model. Finally, reliability of electrical resistivity survey in the centrifuge test was verified by comparing those testing results.

• Journal of the Korean Geotechnical Society
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• v.19 no.4
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• pp.179-190
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• 2003

The grout based on solution type makes it difficult to get the improvement of ground strength and the effefct of water curtain because it has lower strength and durability than suspension type. Nowadays, the technology of particle acceleration, that enhance the material permeability, such as grout based on solution type, and inexpensive grout, is being required. For these reasons, in this study, using wet milling system, we evaluated physical properties of manufactured factors such as water-cement ratio of particles before being milled, optimum milling capacity by controlling milling time and rpm, viscosity of materials, permeation coefficient, and unconfined compressive strength. Also, using micro wet milling apparatus which could manufacture ordinary Portland cement and high speed shear mix which could forcefully separate conglomerate particles in situ, we performed electrical resistivity investigation and falling head permeability tests to analyze differences of grouting effects. From these results, we found that the permeability of the applied equipment was much superior, and in the case of using high speed shear mixer, particles of grout material were well separated.

• Land and Housing Review
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• v.2 no.2
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• pp.145-155
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• 2011

It is very important for successful construction to estimate the soil volume conversion factor of domestic weathered ground accurately and reasonably. However, it is very difficult to quantify the weathering degree of weathered ground at the field, so that the soil volume conversion factor used in Korea is often dependent upon the standard of foreign countries. Besides, the soil volume conversion factor of domestic weathered ground has been rarely studied and the use and accuracy of the soil volume conversion factor have been questioned persistingly. This study suggests a simple but robust method for estimating the soil volume conversion factor and measuring the weathering degree reasonably, and attempts to establish the utilization of a soil volume conversion factor measurement system based on experimental and analytical results. We made relationship between electrical resistivity and weathering degree presented from weathering index obtained through laboratory tests using field samples, and an estimation method of in-situ weathering degree for granites and a calculation method of soil volume conversion factor using electrical resistivity. And also, we suggested the photogrametry measurement-equipment system for measuring the volume of cargo box and the application plan of stand equipment and RFID for calculating the earth volume and distinguishing buggies in order to design the measurement system for soil volume conversion factor applicable to the field. Ultimately, the Weathered Earth-work Management Program (WEMP) was developed, so field managers may easily obtain the information about earth volume and soil volume conversion factor at the weathered ground.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.308-319
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• 2005

Piezo-ceramics are special materials which transform energy between mechanical and electrical forms. Bender-elements are composite materials consisting of thin piezo-ceramics and elastic shims, and are widely used as actuators and transducers in the field of electronics, robotics, autos and mechatronics utilizing the effectiveness of energy transformation capability. In geotechnical engineering, commercial bender-elements are used in laboratory as source and receiver in the measurements of soil stiffness. The elements were built by using various metal shims sandwiched between piezo-ceramics and coating over the composite in the research. A pair of elements were buried in a concrete block and used as source and receiver to measure the stiffness of the concrete. The test results were verified by comparing with the resonant column testing results. In a preliminary stage of the development of an in-situ seismic testing equipment using bender-elements for soft clay materials, shear waves were generated and measured by burying the elements in the barrel of kaolinite and water mixture. The measured shear wave signals were so distinct for the first-arrival pick that applicability of the elements in the field measurements is very promising.