• Investigative Magnetic Resonance Imaging
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• v.8 no.2
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• pp.100-108
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• 2004

Purpose : Early degeneration of articular cartilage is accompanied by a loss of glycosaminoglycan (GAG) and the consequent change of the integrity. The purpose of this study was to biochemically quantify the loss of GAG, and to evaluate the $Gd(DTPA)^{2-}$-enhanced, and T1, T2, rho relaxation map for detection of the early degeneration of cartilage. Materials and Methods : A cartilage-bone block in size of $8mm\;\times\;10mm$ was acquired from the patella in each of three pigs. Quantitative analysis of GAG of cartilage was performed at spectrophotometry by use of dimethylmethylene blue. Each of cartilage blocks was cultured in one of three different media: two different culture media (0.2 mg/ml trypsin solution, 1mM Gd $(DTPA)^{2-}$ mixed trypsin solution) and the control media (phosphate buffered saline (PBS)). The cartilage blocks were cultured for 5 hrs, during which MR images of the blocks were obtained at one hour interval (0 hr, 1 hr, 2 hr, 3 hr, 4 hr, 5 hr). And then, additional culture was done for 24 hrs and 48 hrs. Both T1-weighted image (TR/TE, 450/22 ms), and mixed-echo sequence (TR/TE, 760/21-168ms; 8 echoes) were obtained at all times using field of view 50 mm, slice thickness 2 mm, and matrix $256\times512$. The MRI data were analyzed with pixel-by-pixel comparisons. The cultured cartilage-bone blocks were microscopically observed using hematoxylin & eosin, toluidine blue, alcian blue, and trichrome stains. Results : At quantitation analysis, GAG concentration in the culture solutions was proportional to the culture durations. The T1-signal of the cartilage-bone block cultured in the $Gd(DTPA)^{2-}$ mixed solution was significantly higher ($42\%$ in average, p<0.05) than that of the cartilage-bone block cultured in the trypsin solution alone. The T1, T2, rho relaxation times of cultured tissue were not significantly correlated with culture duration (p>0.05). However the focal increase in T1 relaxation time at superficial and transitional layers of cartilage was seen in $Gd(DTPA)^{2-}$ mixed culture. Toluidine blue and alcian blue stains revealed multiple defects in whole thickness of the cartilage cultured in trypsin media. Conclusion : The quantitative analysis showed gradual loss of GAG proportional to the culture duration. Microimagings of cartilage with $Gd(DTPA)^{2-}$-enhancement, relaxation maps were available by pixel size of $97.9\times195\;{\mu}m$. Loss of GAG over time better demonstrated with $Gd(DTPA)^{2-}$-enhanced images than with T1, T2, rho relaxation maps. Therefore $Gd(DTPA)^{2-}$-enhanced T1-weighted image is superior for detection of early degeneration of cartilage.

• Journal of the Korean Wood Science and Technology
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• v.15 no.3
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• pp.44-55
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• 1987

In order to study the effect of sawdustboard combined with plastic chips, 0.5mm($T_1$), 1mm($T_2$), 1.4mm($T_3$) thick nylon fiber. polypropylene rope fiber(RP), and 0.23mm thick moth-proof polypropylene net fiber(NP) were cut into 0.5, 1, 2cm long plastic chips. Thereafter, sawdustboard combined with plastic chips prepared as the above and plastic non-combined sawdustboard(control) were manufactured into 3 types of one-, two-, and three layer with 5 or 10% combination level. By the discussions and results at this study, the significant conclusions of mechanical and physical properties were summarized as follows: 1. The MORs were shown in the order of 3 layer> 2 layer> 1 layer among plastic non-combined boards, and $T_3$ < $T_2$ < $T_1$ < RP (NP(5%) < NP(l0%) among plastic combined boards. In 2cm long plastic chip in 1 layer board, the highest strength through all the composition was recognized. 1 layer board showing the lower strength with 0.5cm plastic chip rendered to the bending strength improvement by 2 or 3 layer board composition. On the other hand, 2 or 3 layer combined with 1, 2cm long polypropylene net fiber chips incurred MOR's conspicuous decrease requiring optimum plastic chip combined level and consideration to combined type. 2. MOE in plastic non-combined 3 layer board exhibited sandwich construction effect by higher resin content application to surface layer in the order of 3layer>1layer>2layer with the highest stiffness of the board combined with polypropylene chip, while nylon chip-combined board had little difference from plastic non-combined board. In relevant to length and layer effect, 3 layer board combined with the 0.5cm long polypropylene net fiber chip in 5% and 10% combined level presented 34-43% and 44-76% stiffness increase against plastic non-combined board(control), respectively. Moreover, in 1 layer board, 30% stiffness increase with 10% against 5% combined level in the 1 and 2cm long polypropylene net fiber chip was obtained. 3. Stress at proportional limit(Spl) showing the fiber relationship (r: 0.81-0.97) between MOR presented in the order of 1 layer<2 layer<3 layer in plastic non-combined board. Correspondingly, combined effect by layer and plastic chip length was similar to MOR's. 4. Differently from previous properties(MOR, MOE, Spl). work to maximum load(Wml) of 2 layer board approached to that of 3 layer board. Conforming the above phenomenon. 2 layer combined with 0.5cm long polypropylene net fiber chip kept the greater work than 1 layer. The polypropylene combined board superior to nylon -and plastic non - combined board seemed to have greater anti - failing capacity. 5. Internal bond strength(IB), in contrast to MOR's tendency. showed in the order of T1

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.1
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• pp.54-66
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• 2001

The aim of this study was to investigate the fluoride release and some mechanical properties including 3-point bending strength, amount of abrasion, surface hardness, water sorption/solubility and cytotoxicity of the newly developed composite resins containing 8, 16, 24 wt% $SrF_2$ glass filler (VF8, VF16, VF24) and four commercially available composite resins, Heliomolar(HE), Verdonfil(VE), Z100(ZH) and Aelitefil(AE). To investigate cytotoxic effect, agar overlay assay was done. Amount of fluoride released into distilled water was measured over a 62-days period from VF8, VF16, VF24 and HE. Results were as follows: 1. Experimental composite resins showed similar mechanical properties to commercial composite resins, but 3-point bending strength and surface hardness of experimental composite resins were inferior to ZH. 2. Over a 62-day Period, the amount of fluoride released was ordered: VF24>VF16>VF8>HE. In experimental composite resins, the amount of fluoride released was 9-23 times greater than HE and seemed to be proportional to the content of $SrF_2$ glass filler. 3. Experimental composite resins and all control composite resins showed mild cytotoxicity. This study showed significantly greater fluoride release from newly developed composite resins than control(HE) and addition of $SrF_2$ glass filler did not decrease mechanical properties or increase cytotoxicity of composite resin. The results from this study imply that newly developed composite resin have adequate mechanical properites, mild cytotoxicity and some potential for secondary caries prevention.

• Journal of Bio-Environment Control
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• v.23 no.1
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• pp.1-10
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• 2014

This study analyzed the efficiency and uniformity by measuring the temperature change depending on the position in the chamber with the use of QRD (quadratic residue diffusor) microwave capable of inducing even sterilization by changing wavelength phase difference and enhancing the effect on low power. The results are summarized as follows: When irradiating 7 kW of QRD microwave, the highest efficiency was obtained at 35 cm height and in the center of the chamber. When irradiating 5 kW of QRD microwave, high efficiency was obtained on the sides of the chamber. When irradiating 3 kW of QRD microwave to Magnetrons 1, 2 and 3, the temperature uniformity according to the position of the bars was similar in the position of Bar 1 and 2. When irradiating 3 kW of QRD microwave to Magnetrons 3, 4 and 5, the temperature increased by approximately 10 to 20% in Bar 3. When irradiating 5, 7 and 9 kW of magnetron, the average temperature during the irradiation time increased in a similar form independently of the position of the bars. On the other hand, the efficiency of the chamber's proper internal volume was not necessarily proportional to the irradiation dose. When irradiating 3 kW of magnetron for 60 120 and 180 seconds, the temperature increased by approximately 5 to 10 at the edge of the chamber according to the irradiation position of magnetron. The temperature distribution for each position in the horizontal plane was relatively uniform, and the temperature had a tendency to slightly increase at the edge. When irradiating 5, 7 and 9 kW of magnetron, the temperature relatively evenly increased independently of the position of the bars. It was thought necessary to increase the irradiation dose by approximately 10 to 20% by considering the difference in temperature rise according to the position of magnetron.

• Journal of Bio-Environment Control
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• v.14 no.2
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• pp.95-105
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• 2005

This study was carried out to file up using effect and requirement of energy for environmental design data of Pleurotus eryngii growing houses. Heating and cooling Degree-Hour (D-H) were calculated and compared for. some Pleurotus eryngii growing houses of sandwich-panel (permanent) o. arch-roofed(simple) type structures modified and suggested through field survey and analysis. Also thermal resistance (R-value) was calculated for the heat insulating and covering materials of the permanent and simple-type, which were made of polyurethane or polystyrene panel and $7\~8$ layers heat conservation cover wall. The variations of heating and cooling D-H simulated for Jinju area was nearly linearly proportional to the setting inside temperatures. The variations of cooling D-H was much more sensitive than those of heating D-H. Therefore, it was expected that the variations of required energy in accordance with setting temperature or actual temperature maintained inside of the cultivation house could be estimated and also the estimated results of heating and cooling D-H could be effectively used far the verification of environmental simulation as well as for the calculation of required energy amounts. When the cultivation floor areas are all equal, panel type houses to be constructed by various combinations of materials were found to by far more effective than simple type pipe house in the aspect of energy conservation maintenance except some additional cost invested initially. And also the energy effectiveness of multi-span house compared to single span together with the prediction of energy requirement depending on the level insulated for the wall and roof area could be estimated. Additionally, structural as well as environmental optimizations are expected to be possible by calculating periodical and/or seasonal energy requirements for those various combinations of insulation level and different climate conditions, etc.

• Journal of the Korean Wood Science and Technology
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• v.36 no.3
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• pp.1-8
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• 2008

The lateral strength test of bending type was done to investigate the lateral capacity of the double bolt connection of domestic larix glulam according to bolt spacing. In the shear specimen, which is bolted connection in the inserted plate type, the hole of bolt was made, changing the diameter of bolt (12 mm and 16 mm), the number of bolt (single bolt : control and double bolt), the direction of bolt row (in parallel to grain : Type-A and in perpendicular to grain : Type-B) and the bolt spacing (Type-A : 4 d and 7 d and Type-B : 3 d and 5 d). Lateral capacity and failure mode of bolt connection were compared according to conditions. In prototype design (KBCS, 2000), the reduction factor of the allowable shear resistance that the bolt spacing is reduced was calculated. The results were as follows. 1) Bearing stress per bolt in the single and double bolt connection of Type-A was directly proportional to bolt diameter and bolt spacing. Bearing stress of Type-B decreased as bolt diameter was increased, and decreased by 2~10% when bolt diameter was increased. 2) In the single bolt connection and the double bolt connection of Type-A, the splitted failure was formed in the edge direction. When the bolt spacing was 3 d in Type-B, bolt was yielded more in the part of tension than in the part of compression, and the splitted failure started at the bolt in the part of tension. In the 5 d spacing specimen, the bolt in the part of tension was yielded similarly to bolt in the part of compression, and the splitted failure started in the part of compression. 3) In the prototype design, the reduction factor was calculated by non-dimensionizing the yielding load in the standard of bolt spacing (Type A : 7 d and Type B : 5 d). In 12 mm bolt connection, the reduction factor of bolt spacing 4 d (type-A) and single bolt connection was 0.87 and 0.55, respectively, and the reduction factor of bolt spacing 3 d (Type-B) and single bolt connection was 0.91 and 0.55, respectively. In 16 mm bolt connection, the reduction factor of bolt spacing 4 d (type-A) and single bolt connection was 0.96 and 0.76, respectively, and the reduction factor of bolt spacing 3 d (Type-B) and single bolt connection was 0.91 and 0.77, respectively.

• Journal of Bio-Environment Control
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• v.33 no.3
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• pp.156-162
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• 2024

This study was conducted to investigate the effect of rooting volume on the productivity of fresh shoots when growing rosemary in multi-layer cultivation. The 10 cm middle cuttings from which the common rosemary (Rosmarinus officinalis L.) apical bud was removed were planted in a 128-hole tray, rooted, and then transplanted into pots of 125, 200, 550, 750, 1,300, and 2,000 mL to determine the growth characteristics and quantity of young shoots of 1-year-old and 2-year-old rosemary. In the case of 1-year-old rosemary, there was no clear difference in initial growth (30 days after transplanting) between treatments in pot size larger than 550 mL, in the case of 2-year-old rosemary, growth tend to be proportional as the pot became larger. The fresh weight of the underground part of 1-year-old and 2-year-old rosemary was the lowest at 6.9 g and 24.4 g, respectively, when surveyed on July 25 in a 550 mL container, and 10.3 g and 24.9 g, respectively, when surveyed on November 24, and there was a difference between treatments in containers of 750 to 2,000 mL. On the other hand, in the case of 1-year-old rosemary, the fresh weight of the above-ground part increased as the pot became larger, but there was no statistical difference above 1,300 mL, and the fresh weight of 2-year-old rosemary was also significantly higher as the pot became larger. The quality of young shoots was the best for 1-year-old rosemary in a pot of 2,000 mL, but for 2-year-old rosemary, there was a difference in quality depending on the season. Shoot productivity per unit pot was highest at 1,300 mL, but when converted to per unit area, the best was observed at 750 mL. Therefore, the most suitable pot size for intensive production through multi-layer cultivation of rosemary young shoots is judged to be 750 mL (12.5 × 11.5 cm).

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.3 no.1 s.4
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• pp.85-96
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• 2004

The study begin with a basic concept, if the occupancy length of vehicle detector is directly proportional to the delay of vehicle. That is, it analogize vehicle's delay of a occupancy time. The results of a study was far superior in the estimation of a queue length. It is a very good points the operator is not necessary to optimize s1, s2, Thdoc. Thdoc(critical congestion degree) replaced 0.7 with 0.2 - 0.3. But, if vehicles have been experience in delay was not occupy vehicle detector, the study is in existence some problems. In conclusion, it is necessary that stretch queue detector or install paired queue detector. Also I want to be made steady progress a following study relation to this study, because it is required traffic signal control on congestion.

• Journal of the Korean Wood Science and Technology
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• v.13 no.2
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• pp.14-34
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• 1985

One of the techniques for altering the properties of wood that has received considerable attention in the last twenty years is the formation of a wood-polymer composite (WPC) by irradiation and heat-catalyst polymerization of a monomer incorporated into the wood matrix. Wood-polymer composites are the new products having the superior mechanical and physical properties and the combinated characteristics of wood and plastic. The purpose of this experiment was to obtain the basic data for the improvement of wooden materials by manufacturing WPC and Staypak. The species examined was Hyunsasi-Namoo (Populus alba ${\times}$ P. glandulosa) which had not been utilized yet. Methylmethacrylate (MMA) as monomer, benzoyl peroxide (BPO) as initiator and methyl alcohol as bulking agent were used. The monomer containing BPO was impregnated into wood pieces by the dipping and the vacuum process for 2 hours. After impregnation, the treated samples were polymerized on the hot press with pressure and heat-catalyst methods. The results obtained were summarized as follows 1. The monomer loading into wood by the dipping process was 12.13 percent and 29.99 percent by the vacuum. The polymer loading into wood by the dipping process was 6.79 percent and 15.44 percent by the vacuum. 2. Comparing with Staypak, antishrink efficiency (ASE) of WPC was 12.5 to 13.6 percent on the radial direction and 14.70 to 18.63 percent on the tangential. Antiswelling efficiency (AE) was 14.40 to 17.22 percent on the radial direction and 17.18 to 42.1 8 to 42.14 percent on the tangential. Reduction in water absorptivity (RWA) was 8.19 to 15.5 percent. As a whole, the vacuum process was better than the dipping. 3. The specific gravity of control, Staypak and WPC were 0.44, 0.66 and 0.61 to 0.62, respectively. 4. In the bending strength test, the strength in case that the load direction is on the radial surface was greater than that which the load direction is on the tangential. 5. Increasing rate of stress at proportional limit in compression perpendicular to grain was 72.26 percent in case of WPC by the dipping process, 78.93 percent by the vacuum and 99.09 percent in case of Staypak.

• Journal of the Korean Society of Radiology
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• v.7 no.2
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• pp.145-149
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• 2013

Helical Tomotherapy is an innovative means of delivering intensity modulated radiation therapy (IMRT) using a device that merges features of a linear accelerator and helical computed tomography (CT) scanner. Hereat, during helical tomotherapy process, megavoltage computed tomography (MVCT) image are usually used for guiding the precise set-up of patient before/after treatment delivery. But which would certainly increase the total dose for patients, this study was to investigate the imaging dose of MVCT using the cylindrical "Cheese" phantom on a tomotherapy machine. A set of cylindrical "Cheese" phantom was adopted for scanning with respectively pitch value (1, 2, 3 mm) with same number slice (10 slice), same length (approximately 9 cm) and phantom set-ups on the couch of tomotherapy system. The average MVCT imaging dose were measured using A1SL ion chamber inserted in the phantom with preset geometry. The MVCT scanning average dose for the cylindrical "Cheese" phantom was 2.24 cGy, 1.02 cGy, 0.81 cGy during respectively pitch value (pitch 1, 2, 3 mm) with same number slice (10 slice), and same length's average dose was 2.47 cGy, 1.28 cGy, 0.88 cGy respectively (pitch 1, 2, 3 mm). Two major parameters, the assigned pitch numbers and scanning length, where the most important impacts to the dose variation. The MVCT dose was inversely proportional to the CT pitch value. The results may provide a reliable guidance for proper planning design of the scanning region, which is valuable to help minimize the extra dose to patient. Questionnaires were distributed to Radiology departments at hospitals with 300 sickbeds throughout the Pohang region of North Gyeongsang Province concerning awareness and performance levels of infection control. The investigation included measurements of the pollution levels of imaging equipment and assistive apparatuses in order to prepare a plan for the activation of prevention and management of hospital infections. The survey was designed to question respondents in regards to personal data, infection management prevention education, and infection management guidelines.