• Journal of the Korea institute for structural maintenance and inspection
• /
• v.3 no.3
• /
• pp.139-147
• /
• 1999

Six reinforced concrete shear wall, constructured with fully rigid, slit, and infilled types, were tested under both vertical and cyclic loadings. Experimental programs were carried out to evaluate the seismic performance of such test specimens, such as the hysteretic behavior, the maximum horizontal strength, crack propagation, and ductility, under load reversals. All the specimens were modeled in one-third scale size. Based on the test results, the following conclusions can be made. For the diagonal reinforced slit and infilled shear wall specimens, it was found that the failure mode shows very effective crack control and crushing due to slippage prevention of boundary region and reduction of diagonal tension rathar than the brittle shear and diagonal tension failure. The ductility of specimens designed by the diagonal reinforcement for the slit and infilled shear wall was increased 1.72~1.81 times in comparison with the fully rigid shear wall frame. Maximum horizontal load-carrying capacity of specimens designed by the diagonal reinforcement ratio the slit and infilled shear wall was increased respectively by l.14 times and l.49 times in comparison with the standard fully rigid shear wall frame.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
• /
• v.20 no.5
• /
• pp.480-492
• /
• 2009

In this paper, we proposed a broadband U-shaped RFID tag antenna with near-isotropic characteristic at UHF band. The proposed tag antenna is composed of the U-shaped half wavelength dipole and a rectangular shaped feed. The rectangular shaped feed that is located inside U-shaped dipole is connected for conjugate impedance matching with the commercial tag chip. A better constant gain deviation characteristic in the operating frequency band is achieved by inserting a rectangular slit in the lower center of the U-shaped antenna body. On the condition of VSWR<2, the tag antenna had the measured bandwidth of 10.36%, from 860.5 to 954.5 MHz, and 9.84%, from 864.5 to 954 MHz, for antenna without slit and with slit, respectively. On the condition of VSWR<5.8, the tag antennas had the measured bandwidth of 15.78%, from 835.5 to 979.5 MHz, and 15.89%, from 837 to 981.5 MHz, for antenna without slit and with slit, respectively. The difference between the maximum and minimum gain deviations of tag antenna without slit in the operating frequency band is 0.53 dB since the maximum and minimum gain deviations are 3.86 dB and 3.33 dB, respectively. Whereas the difference between the maximum and minimum gain deviations of tag antenna with slit in the operating frequency is 0.06 dB since the maximum and minimum gain deviations are 3.60 dB and 3.54 dB, respectively.

• Journal of Institute of Control, Robotics and Systems
• /
• v.3 no.6
• /
• pp.613-618
• /
• 1997

In this paper, we designed a line CCD camera for a flying image, which is composed of a line CCD sensor(2048 cells) and a rotating mirror, and investigated its optical properties. We also made the 3-D image from the flying image which is made of 2-D image being juxtaposed to 1-D images obtained by the camera, and performed the calibration to acquire high precision 3-D data. As a result, we obtained the 3-D measurement system using the slit type of laser projector is available to measure the high precision shape of objects.

• Journal of the Korean Society for Precision Engineering
• /
• v.12 no.8
• /
• pp.73-85
• /
• 1995

The sensor system to measure the distance precisely from the center of the sensor system to the obstacle is needed to recognize the surrounding environments, and the sensor system is to be calibrated thoroughly to get the range information exactly. This study covers the calibration of the active range sensor which consists of camera and laser slit emitting device, and provides the equations to get the 3D range data. This can be possible by obtaining the extrinsic parameters of laser slit emitting device through image processing the slits measured during the constant distance intervals and the intrinsic parameters from the calibration of camera. The 3D range data equation derived from the simple geometric assumptions is proved to be applicable to the general cases using the calibration parameters. Also the exact 3D range data were obtained to the object from the real experiment.

• Korean Journal of Metals and Materials
• /
• v.49 no.3
• /
• pp.221-230
• /
• 2011

The cold spray process is an emerging technology that utilizes high velocity metallic particles for surface coating. Metallic powder particles are injected into a converging-diverging de Laval nozzle and accelerated to a high velocity by a supersonic gas flow. The cold spray process normally uses a circular nozzle that has a rather narrow spraying range. To overcome this fault, a slit nozzle was considered in this study. The slit nozzle is anticipated to reduce the coating process time because it has a wider coating width than the circular nozzle. However, the slit nozzle can reduce the coating efficiency because it does not allow as much gas and particle velocity as the circular nozzle. To improve the coating efficiency of a slit nozzle, the shape of the slit nozzle was modified. And the results of gas flow and particle behaviour according to the nozzlers shape were compared by the a numerical analysis. As a results, as Expansion Ratio(ER) of 7.5 was found to be the most optimal condition for enhancing the spraying efficiency when the ER was changed by the variation of nozzle neck and exit size.

• Korea-Australia Rheology Journal
• /
• v.16 no.3
• /
• pp.129-134
• /
• 2004

The aggregation characteristics of red blood cells (RBCs) were measured using a newly developed light-transmission slit rheometer. Conventional methods of RBC disaggregation such as the rotational Couette system were replaced with a pressure-driven slit flow system with a vibrational mechanism. Using a vibration generator, one can disaggregate the RBC aggregates stored in the slit. While shear stress decreases exponentially, instantaneous pressure and the transmitted light intensity were measured over time. Applying an abrupt shearing flow after disaggregation caused a rapid elongation of the RBCs followed by loss of elongation with the decreasing shear stress. While the shear stress is further decreasing, the RBCs start to re-aggregate and the corresponding transmitted intensity increases with time, from which the aggregation indices can be obtained using a curve-fitting program.

• Nuclear Engineering and Technology
• /
• v.4 no.3
• /
• pp.223-228
• /
• 1972

In the radiography, of thick materials the scattered rays from an object are one of major causes to reduce the quality of the radiographic image on the film. To determine the rate of scattering of incident gamma rays by an objective specimen, film blacknesses are measured for various slit widths. For each measurement, the changes of a penetrameter's sensitivity are also evaluated. It is observed that the fault-detectability can be improved by reducing the slit width when the fault detectability deteriorates due to the increase in scattered gamma rays by thicker samples. This experiment has been carried out with the iron specimens and $^{60}$ Co source.

• Journal of the Optical Society of Korea
• /
• v.13 no.3
• /
• pp.330-334
• /
• 2009

A simple and compact frequency swept laser is demonstrated at $1.3{\mu}m$ using a wavelength scanning filter based on a rotating slit disk. The laser is comprised of a pigtailed semiconductor optical amplifier, a circulator, and a wavelength scanning filter in an extended cavity configuration. The wavelength scanning filter is composed of a collimator, a diffraction grating, a rotating slit disk, and a mirror. The instantaneous laser output power is more than 5 mW. The scanning range of the laser is extended to 80 nm at the maximum level, and 55 nm in the full width at half maximum at a scanning rate of 2 kHz.

• Proceedings of the KIEE Conference
• /
• 1997.07a
• /
• pp.41-43
• /
• 1997

This paper represents the comparison of harmonic loss characteristics of the inverter-driven 3-phase squirrel cage induction motor with slit and U-iron bridge slots of rotor. Two-dimensional time-stepped finite element method is used for electromagenetic field analysis. And spectrums of bar current, phase current, and torque are compared in each case.

• Korean Journal of Heritage: History & Science
• /
• v.45 no.4
• /
• pp.4-21
• /
• 2012

Jade ornaments, which include slit earrings, scoop-shaped objects and tubular beads have been extensively identified in Northeast Asia, such as Korea, China, Japan and the Maritime Province of Siberia. Among them slit earrings are distributed in the whole area of Northeast Asia. Although this object shows the typological differences in accordance with the excavated region in detail, all of them are characterised by the slit on the centre of jade ring. The buried context and the shape of this object suggest that this artefact was the earring; thus it is named to 'slit earring'. Most of slit earrings of the Neolithic Age concentrate in Northeast China and the areas south of the Yangtze River, and the Japanese Archipelago. However, unfortunately, Slit earrings, which were produced in the tradition of the incipient and early phases of the Neolithic Age in Northeast Asia, have not been excavated in the Korean Peninsula. The number of slit earrings reported so far is eight, and especially until the 20th century, almost none was reported with its exact excavation location and only three of them are known as excavated through surface surveys and preliminary excavations. However, from the beginning of the 21st century onwards, the number of discovered slit earrings is increasing. Particularly, five pieces of this object uncovered in the 21st century are discovered in the official excavation; thus the exact archaeological context such as buried locations and chronologies could be estimated. By considering the buried context, slit earrings are associated with stone axes, which were produced in the incipient and early phase of the Neolithic Age in the Korean Peninsula. In addition, considering the number of unearthed objects is a few, it could be postulate that slit earring was the artefact that only a few persons, who had a special role in the society, could possess. However, slit jade earrings that have been excavated in the Korean Peninsula are extremely low in their number compared to the cases of its neighbouring countries such as China and Japan, and the researches on this subject have not been much conducted in Korea. Therefore, it is my supposition that slit earrings, which have been discovered in the Korean Peninsula, might be the imported item from the nearby areas. Particularly, the Southern Coast was closely connected with Japanese Islands and the Eastern Coast was interchanged with Northeast China or the Maritime Province of Siberia. Considering that excavations and researches on the Neolithic remains in the Korean Peninsula have not been sufficiently and actively conducted, it could be expected that the further investigations and researches will reveal the sufficient quantities of slit earrings in near future.