• Korean Journal of Soil Science and Fertilizer
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• v.12 no.4
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• pp.169-178
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• 1980

Ammonium nitrate explosion technique was applied to seek a convenient method for the establishment of orchard on the undulating to rolling land or hill side of Pogog clay loam soil (Fine Aquic Fragiudalfs : Planosols) having high bulk density and low permeability. Explosions were made by three ammonium nitrate explosives placed in the bottom of 90cm deep auger hole with every 2m interval (Explosion I) and 4m interval (Explosion II) respectively. The effect of the explosion on physical properties of the soil was investigated and compared with the effect induced by manual digging, excavation of $1m{\times}1m$ in diameter and depth (Manual digging I) and trenching of $1m{\times}1m{\times}25m$ in width, depth, and length (Manual digging II) respectively. The results investigated after 7 months from the treatments are summarized as follows : 1. The explosion or manual digging reduced bulk density and hardness, whereas the treatments increased porosity, hydraulic conductivity, and available moisture-holding capacity of the soil. 2. The explosion of 4 m interval improved physical properties of the soil to optimum level up to 70cm of the distance from the explosion core in the range of depth 0-60cm, while in the case of depth from 60 to 100cm the optimum level was achieved only within 50cm radius. 3. When exploded in 2 m interval, the effect in the 0-60cm depth was overlapped between two explosion cores. The effect in the depth between 60 and 100cm, however, was found to be independent of the explosion intervals. 4. The manual digging was only costly and laborious but effective only within the work-up zone. 5. For the soils having bulk density higher than $1.4g/cm^3$ after the treatments, the field capacity determined 72 hours after a heavy rain was lower than the laboratory estimate at the suction of 1/3 atm. 6. The top growth of apple tree for the first year revealed that the explosion seemed better treatment than the manual digging, even though the difference was insignificant.

• The Korean Journal of Nuclear Medicine
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• v.34 no.1
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• pp.82-93
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• 2000

Purpose: We characterized the signals obtained from the components of a small gamma camera using Nal(Tl)-position sensitive photomultiplier tube (PSPMT) and optimized the parameters employed in the modules of the system. Materials and Methods: The small gamma camera system consists of a Nal(Tl) crystal ($60{\times}60{\times}6mm^3$) coupled with a Hamamatsu R3941 PSPMT, a resister chain circuit, preamplifiers, nuclear instrument modules (NIMs), an analog to digital converter and a personal computer for control and display. The PSPMT was read out using a resistive charge division circuit which multiplexes the 34 cross wire anode channels into 4 signals (X+, X-, Y+, Y -). Those signals were individually amplified by four preamplifiers and then, shaped and amplified by amplifiers. The signals were discriminated and digitized via triggering signal and used to localize the position of an event by applying the Anger logic. The gamma camera control and image display was performed by a program implemented using a graphic software. Results: The characteristics of signal and the parameters employed in each module of the system were presented. The intrinsic sensitivity of the system was approximately $8{\times}10^3$ counts/sec/${\mu}Ci$. The intrinsic energy resolution of the system was 18% FWHM at 140 keV. The spatial resolution obtained using a line-slit mask and $^{99m}Tc$ point source were, respectively, 2.2 and 2.3 mm FWHM in X and Y directions. Breast phantom containing $2{\sim}7mm$ diameter spheres was successfully imaged with a parallel hole collimator. The image displayed accurate size and activity distribution over the imaging field of view Conclusion: We proposed a simple method for development of a small gamma camera and presented the characteristics of the signals from the system and the optimized parameters used in the modules of the small gamma camera.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.5
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• pp.59-66
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• 2020

Recently, cultivation and management technologies have been needed to adapt due to climate change, which is causing abnormal weather conditions. One technique is to increase the utilization of evergreen broad-leaved species with high ornamental value. A total of five treatments were installed (1m×22.5m), including 60g/㎡ and 80g/㎡ using two types mulching material with an overlapping and hole-drilling mulching method and these were compared to un-mulching treatment a total of planted 92㎡ attheWol-aTestSiteForestattheForestforBiomaterialsResearchCenterinJinju-si, Gyeongsangnam-dofor 10monthsusing3-years-oldQuercusglaucaThunb. In comparison with the control site, the 60g/㎡ overlapping method was about 1.9 times higher than the root collar diameter, but there was no statistical significance between the treatments. Healthy seedlings were found to meet these conditions due to high biomass values and below and T/R ratios of 3.0 or lower and H/D ratios of 7.0 or lower. Comparing the values of LWR, SWR, and RWR, which can be evaluated for seedling due to the mulching treatments, as compared to the control, the growth of the ground areas including leaves and stems was enhanced, but the growth of the underground areas containing roots tended to have high control values. Based on this, the SQI value, which can be evaluated for the comprehensive quality of seedlings, was found to be significantly different between the control site and the mulching treatment sites, confirming that the growth and growth improvement effects were achieved with mulching treatments. The chlorophyll content analysis showed that there was a significant difference from the control site, and it was judged that weed generation in the control acted as an environmental stress, causing a decrease in chlorophyll content. It was found that the overlapping 80g/㎡ of polypropylene mulching material generated about 4 times fewer weeds than the control, and the manpower required for the mulching test field and weeding were equal at 3.3 people/100㎡/1 day. Mulching treatments have demonstrated a significant difference in the promotion of growth and quality of the seedlings and are judged as an alternative that can reduce the economic burden incurred by the purchase of the supplies and the manpower required to weed forestry plantations.

• Journal of Bio-Environment Control
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• v.20 no.2
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• pp.150-155
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• 2011

The aim of this study was investigated long distance export condition of paprika from Korea to Canada, and evaluated the effect of non-perforated breathable films on the storability of paprika during MA storage in the simulated long distance export condition. The long distance export condition of paprika from Korea to Canada was $7{\pm}1^{\circ}C$ and RH 90% during shipping for 20 days, and then the temperature of that was increased to $13^{\circ}C$ for 3 hours during transferring from refrigerated container to storage room in Canada, and decreased $3{\sim}4^{\circ}C$ for 3 days before distributing to local markets. The temperature and relative humidity of local markets was $16^{\circ}C$ and 60%, respectively. The packing material treatments were non-packing, as control, perforated film (6 mm diameter hole, $18holes/m^2$), and 3 kind of laser treated non-perforated films (oxygen transmission rate was 5,000, 20,000 and 100,000 $cc/m^2{\cdot}day{\cdot}atm$). Under the simulated long distance export condition; $7^{\circ}C$ and RH 90% for 15 days and then $20^{\circ}C$ and RH 55% for 7 days, the fresh weight loss of paprika was less than 1% in 3 kind of laser treated non-perforated film treatments but was more than 4% in control and perforated film treatment that showed severe deterioration of visual quality after 20 days of storage. The atmosphere of paprika packages was changed 5% oxygen and 15% carbon dioxide in 5,000 $cc/m^2{\cdot}day{\cdot}atm$ treatment, and 16% oxygen and 4~5% carbon dioxide in 20,000 $cc/m^2{\cdot}day{\cdot}atm$ treatment during room temperature storage after cold storage for 15 days. A carbon dioxide concentration of these 2 treatments was exceeded the optimal MA and CA condition. There was no significant difference in ethylene concentration among 3 kind of laser treated non-perforated film treatments. A paprika packed with 100,000 $cc/m^2{\cdot}day{\cdot}atm$ non-perforated film showed the highest visual quality under the simulated long distance export condition. However, the firmness and soluble solids did not show any significant difference among 3 kind of laser treated non-perforated film treatments. Therefore, we may suggest that 100,000 $cc/m^2{\cdot}day{\cdot}atm$ laser treated non-perforated film was the proper film for MAP of paprika under long distance export condition that was $7{\pm}1^{\circ}C$ and RH 90% for 15 days, and then $20^{\circ}C$ and RH 55% for 7 days.

• Journal of Korean Ophthalmic Optics Society
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• v.7 no.1
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• pp.39-43
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• 2002

This study was investigated the anti-angiogenic activities of Cnidium officinale Makino and Tabanus bovinus by using Chorioallantoic membrane (CAM) and rat cornea. First experiment, the fertilized chicken eggs were kept in a humidified egg incubator at $37^{\circ}C$. After 4 days incubation, about 3 ml of albumin was aspirated from eggs with an hypodermic needles through a small hole drilled at the narrow end of the eggs, and the shell membrane on the floor of the air sac was peeled away. Embryos with chorioallantois of 3~5 mm in diameter were employed for the assay of antiangiogenic activity. Retinoic acid was used as a positive control for this experiment. After 48 h of treatment. branching pattern of blood vessels below coverslip containing retinoic acid ($10{\mu}g/egg$) was dramatically decreased. A simiar angiogenic inhibition was observed in the CAM treated with $50{\mu}g/egg$ of Cnidium omcinale Makino and Tabanus bovinus extracts. Second experiment, rat corneal neovascularization was induced by suturing (one stitch) the cornea with 10-0 nylon, and terramycin was applied on the cornea for I week to prevent corneal inflammation. In the cornea of rats untreated with herbal extracts, numerous vessels were usually seen invading the cornea by day 2 or 3 after suture, and reaching the lesion area within 5~6 days. Corneal neovascularization was gradually increased and peaked at 3 weeks. In contrast to this, herbal extracts conspicuously inhibited the angiogenesis, Oral administration of herbal extracts (20 mg/kg body weight/day) for 4 weeks significantly inhibited the rat corneal angiogenesis induced by suture, and the length of blood vessels in herbal medicine-treated rat cornea was conspicuously lower than that in control animals. A similar phenomenon was also observed in the rat cornea treated with thalidomide (200 mg/kg body weight/day). These findings indicate the anti-angiogenic properties of Cnidium officinale Makino and Tabanus bovinus, suggesting that these properties may be one of the pharmacological mechanisms underlying the anti-tumor and anti-metastatic activities of herbal extracts tested in this study.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.4
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• pp.301-311
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• 2011

Introduction: This study examined the effect of the application of low intensity pulsed ultrasound on bone healing after an injection of adipose tissue-derived stem cells (ADSCs) during the implantation of a titanium implant in the tibia of diabetes-induced rats. Materials and Methods: Twelve Sprague-Dawely rats were used. After inducing diabetes, the ADSCs were injected into the hole for the implant. Customized screw type implants, 2.0 mm in diameter and 3.5 mm in length, were implanted in both the tibia of the diabetes-induced rats. After implantation, LIPUS was applied with parameters of 3 MHz, 40 mW/$cm^2$, and 10 minutes for 7 days to the left tibiae (experimental group) of the diabetesinduced rats. The right tibiae in each rat were used in the control group. At 1, 2 and 4 week rats were sacrificed, and the bone tissues of both tibia were harvested. The bone tissues of the three rats in each week were used for bone-to-implant contact (BIC) and bone area (BA) analyses and the bone tissues of one rat were used to make sagittal serial sections. Results: In histomorphometric analyses, the BIC in the experimental and control group were respectively, $39.00{\pm}18.17%$ and $42.87{\pm}9.27%$ at 1 week, $43.74{\pm}6.83%$ and $32.27{\pm}6.00%$ at 2 weeks, and $32.62{\pm}11.02%$ and $47.10{\pm}9.77%$ at 4 weeks. The BA in experimental and control group were respectively, $37.28{\pm}3.68%$ and $31.90{\pm}2.84%$ at 1 week, $20.62{\pm}2.47%$ and $15.64{\pm}2.69%$ at 2 weeks, and $11.37{\pm}4.54%$ and $17.69{\pm}8.77%$ at 4 weeks. In immunohistochemistry analyses, Osteoprotegerin expression was strong at 1 and 2 weeks in the experimental group than the control group. Receptor activator of nuclear factor kB ligand expression showed similar staining at each week in the experimental and control group. Conclusion: These results suggest that the application of low intensity pulsed ultrasound after an injection of adipose tissue-derived stem cells during the implantation of titanium implants in the tibia of diabetes-induced rats provided some positive effect on bone regeneration at the early stage after implantation. On the other hand, this method is unable to increase the level of osseointegration and bone regeneration of the implant in an uncontrolled diabetic patient.

• Restorative Dentistry and Endodontics
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• v.33 no.4
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• pp.405-412
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• 2008

This study was aimed to investigate whether an oxygen inhibition layer (OIL) is essential for the interfacial bonding between resin composite layers or not. A composite (Z-250, 3M ESPE) was filled in two layers using two aluminum plate molds with a hole of 3.7 mm diameter. The surface of first layer of cured composite was prepared by one of five methods as followings, thereafter second layer of composite was filled and cured: Group 1 - OIL is allowed to remain on the surface of cured composite; Group 2 - OIL was removed by rubbing with acetone-soaked cotton; Group 3 - formation of the OIL was inhibited using a Mylar strip; Group 4 - OIL was covered with glycerin and light-cured; Group 5 (control) - composite was bulk-filled in a layer. The interfacial shear bond strength between two layers was tested and the fracture modes were observed. To investigate the propagation of polymerization reaction from active area having a photo-initiator to inactive area without the initiator, a flowable composite (Aelite Flow) or an adhesive resin (Adhesive of ScotchBond Multipurpose) was placed over an experimental composite (Exp_Com) which does not include a photoinitiator and light-cured. After sectioning the specimen, the cured thickness of the Exp_Com was measured. The bond strength of group 2, 3 and 4 did not show statistically significant difference with group 1. Groups 3 and 4 were not statistically significant different with control group 5. The cured thicknesses of Exp_Com under the flowable resin and adhesive resin were 20.95 (0.90) urn and 42.13 (2.09), respectively.

• The Korean Journal of Physiology
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• v.1 no.2
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• pp.169-175
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• 1967

An experiment was designed to see if the hippocampus exerts any influence upon the aggressive behavior of male rats. Fighting between rats was observed for the estimation of aggressiveness. Seventeen rats in which the hippocampus was almost totally removed through a small hole with a diameter around 3 mm made in the neocortex at the boundary between the parietal and occipital lobes (hippocampal group), 8 rats with similar neocortical damage alone (operated control group), and 17 normal control rats (normal group) were prepared and subjected to the experiment 3 months after the operation. Applying electric shock of short duration to the feet in a box with grid floor, a fight was provoked between an animal belonging to the hippocampal group and one belonging to the nor-mal group, between a rat of the hippocampal group and one of the operated control group, and also between a rat of the operated control group and one of the normal group. Three observers judged the performance of each animal independently and described it as winning, defeated, tied, or non-fighting. Fifteen shocked trials were administered to each pair of animals with around 2 minutes' interval between each trial. An animal received a 'judging score' of 3 when it won more frequently than was defeated, a judging score of 2 when it won as frequently as was defeated, when all fights were tied, or when no fighting occurred, while it received a judging score of 1 when it won less frequently than was defeated. Group differences in performances were analyzed in terms of judging score using Kolmogorov-Smirnov test for one sample. The results obtained were as follows: 1. In the fights between the hippocampal and the normal groups, the hippocampal animals made significantly better judging scores than the normal animals did (Table 1). 2. There was no significant difference between the hippocampal and the operated control group as to the judging scores they made in the course of fights between the two groups. However, the hippocampal animals tended to dominate over the operated control group as judged by comparing the total 'winning' of the former (30) to that of the latter (14) (Table 2). 3. The total judging score made by the operated control group in the course of the fights against the normal group was not significantly superior to that made by the normal group (Table 3). It was inferred from the above results that, though inconspicuous, the hippocampus tended to exert an inhibitory influence upon the aggressive behavior of male rats.

• Geophysics and Geophysical Exploration
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• v.25 no.4
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• pp.167-176
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• 2022

We designed a borehole deviation survey tool applicable for steel-cased holes, K-DEV, and developed a prototype for a depth of 500 m aiming to development of own equipment required to secure deep subsurface characterization technologies. K-DEV is equipped with sensors that provide digital output with verified high performance; moreover, it is also compatible with logging winch systems used in Korea. The K-DEV prototype has a nonmagnetic stainless steel housing with an outer diameter of 48.3 mm, which has been tested in the laboratory for water resistance up to 20 MPa and for durability by running into a 1-km deep borehole. We confirmed the operational stability and data repeatability of the prototype by constantly logging up and down to the depth of 600 m. A high-precision micro-electro-mechanical system (MEMS) gyroscope was used for the K-DEV prototype as the gyro sensor, which is crucial for azimuth determination in cased holes. Additionally, we devised an accurate trajectory survey algorithm by employing Unscented Kalman filtering and data fusion for optimization. The borehole test with K-DEV and a commercial logging tool produced sufficiently similar results. Furthermore, the issue of error accumulation due to drift over time of the MEMS gyro was successfully overcome by compensating with stationary measurements for the same attitude at the wellhead before and after logging, as demonstrated by the nearly identical result to the open hole. We believe that the methodology of K-DEV development and operational stability, as well as the data reliability of the prototype, were confirmed through these test applications.