• Transactions of the Korean hydrogen and new energy society
• /
• v.35 no.2
• /
• pp.185-194
• /
• 2024

Fe-Ni nanocatalysts loaded on carbon black were prepared via spontaneous reduction reaction of iron (II) acetylacetonate and nickel (II) acetylacetonate in dry process. Their morphology and elemental analysis were characterized by scanning electron microscopy, transmission electron microscopy (TEM), and energy dispersive X-ray analyzer. The loading weight of the nanocatalysts was measured by thermogravimetric analyze and the surface area was measured by BET analysis. TEM observation showed that Fe and Ni nanoparticles was well dispersed on the carbon black and their average particle size was 4.82 nm. The loading weight of Fe-Ni nanocatalysts on the carbon black was 6.83-7.32 wt%, and the value increased with increasing iron (II) acetylacetonate content. As the Fe-Ni loading weight increased, the specific surface area decreased significantly by more than 50%, because Fe-Ni nanoparticles block the micropores of carbon black. I-V characteristics showed that water electrolysis performance increased with increasing Ni nanocatalyst content.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.26 no.3
• /
• pp.311-322
• /
• 2010

The purpose of this study was to evaluate the bond strengths between IPS e.max Press and four different types of resin cements that often used for esthetic restoration. Disc shaped IPS e.max Press blocks(N=40, diameter: 12mm, thickness: 3mm) were fabricated according to the manufacture's instruction and cleaned with ultrasonic cleaner. They were embedded into an autopolymerizing acrylic resin. Fourty cylinder shaped resin block(Filtek Z350, diameter: 4.5mm, thickness: 3mm) were fabricated using a plastic tube. Each specimens were randomly divided into 4 experimental group and bonded each other using 4 different resin cements(Variolink II(light-cure), Variolink II(dual-cure), Calibra, Super-Bond C&B) according to the manufactures' recommendations. All the specimens were stored in normal saline at $37^{\circ}C$ for 24 hours before test. Universal testing machine at a crosshead speed of 1mm/min was used to evaluate the shear bond strength. The data were statistically analyzed using one-way ANOVA(P<.01). Multiple comparison was done by the Tukey HSD test. The shear bond strength of Super-Bond C&B to e.max was significantly lower than those of Calibra, Variolink II(light-cure), Variolink II(dual-cure) (P<.01). The shear bond strength of Calibra, Variolink II(light-cure), Variolink II(dual-cure) to e.max were not significantly different. The shear bond strengths of light-cure/dual-cure cement were higher than that of self-cure cement.

• The Korean Journal of Petroleum Geology
• /
• v.5 no.1_2 s.6
• /
• pp.27-35
• /
• 1997

The Gorae II area is located in the southwestern margin of the Ulleung Basin, East Sea and corresponds to the Ulleung Trough. The survey of 3D seismic data in this area was performed to delineate the structural leads confirmed by the previous 2D seismic data. As a part of 3D interpretation, basement related structural movements and their relationship with the stratigraphy were studied. The study shows that eight sequences were identified which are genetically related to the tectonics and sediment supply in this area. The geologic structures characterizing the study area consist of : (1) block faults developed in the early stage of basin opening, (2) late Miocene thrusts, and (3) Pliocene wrench faults. The eight sequences consist of pre-rift (acoustic basement), syn-rift (Sequence $A_1, A_2$), post-rift (Sequence $B_1{\~}B_3$), syn-compressional sequence (Sequence C), and post-compressional sequence(Sequence D) from oldest to youngest. The time structure and isochron maps were constructed for each sequence and also used in seismic facies analysis and interpretation of sedimentary environment. The interpretation results reveal that the relative sea level changes caused by several stages of tectonic movements and sediment supply control the stratal and structural geometry of Ulleung basin.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.14 no.1
• /
• pp.2535-2548
• /
• 1972

Instead of fertilizing the lands they moved to find other fertile lands and lived a feudal life agriculture and various machincs played a main role in the land reclamation. The best method of land clearing, the time and capacity in the operation and the effect of growing crops should systematically analized prior to the time of 3rd Five-year Economic Development(1972-1976) in order to cultivate 210,000ha of wasteland or the modernization of our country. The present study was investigated to find out a new working-system of mechanical land clearing and development of fertile soil. The results are as follows: 1) The first stage of productive power increases when weeds were mixed soil in the land clearing work in order to supply organic materials and to make soil swollen instead of burning or just removing. 2) The equipments such as bulldozers, harrows, power tillers and so on should be prepared in order to do a systematic work in the land clearing. 3) The work of pulling-up roots is dependent upon the forms of roots spreading under the ground. The work of the pulling-up of the straight roots was most difficult. But before the roots are pulling-up we do not know the forms of roots. 4) The cutting of soil from upside to under side land clearing method (II) Spent 6 hr 7 min 43 sec per 1 Danbo in doing land clearing and control method spent 4 hr 52 min 30 sec per 1 Danbo in doing land cearing. No significant difference could be found between II treatment type and I treatment type. 5) The volume of soil carried by bulldozer $270.38m^3$ per 1 Danbo in I type and in II type, $368.58m^3$ per 1 Danbo or about 36% increased in II type then in I type. But that is not a significant difference when considering the whole productive power of soil. 6) The land clearing of terrace by bulldozers cannot escape making the embankment slope of about $45^{\circ}$, and 25.3% should be decreased in the area. It is recommended to make use of the embankment slope by planting grass for cows. 7) The time of retary tilling increased 2.3 times or 1 hr 42 min 22 sec per 1 Danbo compared to the timesrequired in the harrowing. Because it mixed the Organic matter on ground and the harrowing of subsoil. 8) The havest of pasture growing on the land reclamation in natural slope is as follows. (a) The none fertilizers with reclaimed block of productivity decresed 1/10 than that of the farmland. Therefore the none fer tilizing in the cultivated pasture is unprofitable. (b) The havest of the manured IV treatment block was the best not only in the kinds of fertilizers but also in the kinds of pasture grass.

• Journal of Chest Surgery
• /
• v.16 no.1
• /
• pp.138-145
• /
• 1983

The value of exfoliative sputum cytology in diagnosis of lung cancer has been accepted with bronchoscopic technique and results has been much improved by foreign investigators, but there was not presented accurate reports for sputum cytologic evaluation in Korea. We tried to find indicators of cytologic tests result in our hospital. During the period between May, 1980 and August, 1982, 400 patients, tested at Department of Thoracic and Cardiovascular Surgery of Kosin Medical College, had diagnostic bronchofiberscopic examination, and the cytologic study of sputum and bronchial secretions were performed. The sputum or bronchial secretion during bronchofiberscopic examination were obtained with various methods and the name of specimen were labeled as I, ASPIRATION SPUTUM, which was collected initially endobronchial sputum as introducing of scope, II, WASHING SPUTUM, which was collected washing bronchial secretion, III, BRUSHING SPUTUM, which was washing solution of brushing instrument and endobronchial sputum after brushing of lesions, IV, POST-SCOPIC SPUTUM, which was expectorated sputum as soon as removing of scopic instrument, V, ALL SPUTUM CYTOLOGY & CELL BLOCK, which was collected all specimen of above procedures. The diagnostic results of bronchofiberscopic examination was disclosed 174 cases [43.5%] of proved lung cancer, 47 cases [11.8%] of suspected lung cancer in grossly, and 179 cases [44.8%] of others finding except cancer. Patient with bronchofiberscopically grossly evidence of lung cancer which were not confirmed histologically or cytologically were excluded from this cytologic study. Histologic and cytologic correlation in proven lung cancer, 174 cases was revealed that number of cytologic positive patients were 45 cases [38.7%] among the 117 cases of proved squamous cell carcinoma, 12 cases [38.7%] among hislogically unknown cancer 34 cases and 6 cases [33.3%] among small cell undifferentiated carcinoma 18 Gases. Total cytologic positive result was presented as 67 cases [38.3%]. The other type of lung cancer, histologically, could not comparison because of small cases. The sequence of positive cytologic result in I-V specimen were disclosed as II, WASHING SPUTUM 57.6%, and V, ALL SPUTUM & CELL BLOCK 41.4%. The I, III & IV result were 28.6%, 22.2% and 26.1% respectively.

• Journal of the Korea Computer Industry Society
• /
• v.4 no.4
• /
• pp.547-552
• /
• 2003

In this thesis, interference phenomena of bluetooth networks requiring Security were minimized; strengthened security of piconet by assigning an identical PIN code to bluetooth devices, which was establishing a specific piconet during authentication stage. To establish a bluetooth piconet system. an unique ID was assigned to each bluetooth device, communication algorithms having different data formats between devices was designed, and an embedded hardware module using ARM processor and uCOS-II RTOS was implemented. About 30% of CPU efficiency in the module was increased by modifying functions including block parameters to work as nonblocking; by the increased efficiency of total piconet, the module could be used as an access point. The module could transmit maximum 10 frames of image and also audio signal by switching the packet effectively according to channel condition. By above-mentioned process, video, audio, and data could be well transmitted by the bluetooth managing program and the possibility of a commercial remote control system using bluetooth technology was suggested.

• Korean Journal of Materials Research
• /
• v.20 no.9
• /
• pp.472-477
• /
• 2010

$Al_2O_3$ has received wide attention with established use as a catalyst and growing application in structural or functional ceramic materials. On the other hand, the boehmite (AlO(OH)) obtained by sol-gel process has exhibited a decrease in surface area during phase transformation due to a decline in surface active site at high temperature. In this work, $Al_2O_3$-CuO/ZnO (ACZ) and $Al_2O_3$-CuO/CeO (ACC) composite materials were synthesized with aluminum isopropoxide, copper (II) nitrate hemi (pentahydrate), and cerium (III) nitrate hexahydrate or zinc (II) nitrate hexahydrate. Moreover, the Span 80 as the template block copolymer was added to the ACZ/ACC composition to make nano size particles and to keep increasing the surface area. The ACZ/ACC synthesized powders were characterized by Thermogravimetry-Differential Thermal analysis (TG/DTA), X-ray Diffractometer (XRD), Field-Emmision Scanning Electron Microscope (FE-SEM), Bruner-Emmett-Teller (BET) surface analysis and thermal electrical conductivity (ZEM-2:M8/L). An enhancement of surface area with the addition to Span 80 surfactant was observed in the ACZ powders from 105 $m^2$/g to 142 $m^2$/g, and the ACC powders from 103 $m^2$/g to 140 $m^2$/g, respectively.

• The Journal of Korean Institute of Communications and Information Sciences
• /
• v.22 no.10
• /
• pp.2317-2328
• /
• 1997

The objective of this paper is to develop an algorithm for a real-time automatic fingerprint recognition system. The algorithm employs the wavelet transform(WT) and the dominat local orientation that derived from the gradient Gaussian(GoG) and coherence in determining the directions of ridges in fingerprint images. By using the WT, the algorithm does not require conventional preprocessing procedures such as smothing, binarization, thining and restoration. For recognition, two fingerprint images are compared in three different ST domains;one that represents the original image compressed to quarter(LL), another that shows vertical directional characteristic(LH), and third as the block that contains horizontal direction(HL) in WT domain. Each block has dominat local orientation that derived from the GoG and coherence. The proposed algorithm is imprlemented on a SunSparc-2 workstation under X-window environment. Our simulation results, in real-time have shown that while the rate of Type II error-Incorrect recognition of two identical fingerprints as the identical fingerprints-is held at 0%, the rate of Type I error-Incorrect recognitionof two identical fingerprints as the different ones-is 2.5%.

• The Journal of Information Technology
• /
• v.3 no.2
• /
• pp.39-47
• /
• 2000

Among the compression methods of moving picture information, a motion estimation method is used to remove time-repeating. The Block Matching Algorithm in motion estimation methods is the commonest one. In recent days, it is required the more advanced high quality in many image processing fields, for example HDTV, etc. Therefore, we have to accomplish not by means of Partial Search Algorithm, but by means of Full Search Algorithm in Block Matching Algorithm. In this paper, it is suggested a structure that reduce total calculation quantity and size, because the structure using Bit Plane select and use only 3bit of 8bit luminance signal.

• Journal of the Korean Institute of Telematics and Electronics C
• /
• v.36C no.1
• /
• pp.59-65
• /
• 1999

In this paper, we design a entorpy encoder of HDTV/DTV encoder blocks on the basis of MPEG-II. The designed entropy encoder outputs its bit stream at 9Mbps bit rate inserting zero-stepping block to protect the depletion of buffer in case that the generated bit stream is stored in buffer and uses not only PROM bit combinational circuit to solve the problem of critical path, and packer block, one of submerge, is designed to packing into 24 bit unit using barrel shifter, and it is constructed to blocks of header information encoder, input information delay, submerge, and buffer control. Designed circuits is verified by VHDL function simulation, as a result of performing P&R with Gate compiler that apply $0.8{\mu}m$ Gate Array specification, pin and gate number of total circuits has been tested to each 235 and about 120,000.