• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.346-351
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• 2018

Metal three-dimensional (3D) printing technologies are mainly classified as powder bed fusion (PBF) and direct energy deposition (DED) methods according to the method of application of a laser beam to metallic powder. The DED method can be used to fabricate fine and hard 3D metallic structures by applying a strong laser beam to a thin layer of metallic powder. The PBF method involves slicing 3D graphics to be a certain height, laminating metal powders, and making a 3D structure using a laser. While the DED method has advantages such as laser cladding and metallic welding, it causes problems with low density when 3D shapes are created. The PBF method was introduced to address the structural density issues in the DED method and makes it easier to produce relatively dense 3D structures. In this paper, thin lines were produced by using PBF 3D printers with stainless-steel powder of roughly $30{\mu}m$ in diameter with a galvano scanner and fiber-transferred Nd:YAG laser beam. Experiments were carried out to find the optimal conditions for the width of a line depending on the processing times, laser power, spot size, and scan speed. The optimal conditions were two scanning processes in one line structure with a laser power of 30 W, spot size of $28.7{\mu}m$, and scan speed of 200 mm/s. With these conditions, a minimum width of about $85.3{\mu}m$ was obtained.

• Journal of Korean Tunnelling and Underground Space Association
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• v.4 no.3
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• pp.175-184
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• 2002

Ground reaction curve is very useful information for estimating the installation time of the tunnel support. The ground reaction curve can be estimated by analytical closed form solutions derived in case of circular section and isotropic stress condition. The nature of the ground reaction, however, depends significantly on tunnel configurations. Nevertheless, few purely analytical and experimental studies of this problem due to tunnel configurations appear to have been carried out. Therefore, it is necessary to investigate the influence of tunnel configurations in order to use simply in practical design. This paper describes a numerical study for the intial elastic displacement in the ground reaction curve due to configuration of tunnel excavation. In order to evaluate the applicability of analytical closed form solution in practical design, the parametric studies were carried out by numerical analysis in elastic tunnel behaviour. In the studies, S value, namely configuration factor, defined as the ratio between tunnel height (b) and width (a), varies between 0.5 and 3.0, initial ground vertical stress varies between 5~30 MPa for each S values. The results indicated that the self-supportability of ground is larger in the ground having low S value. It, however, is suggested that the applicability of closed form solution may not be adequate to determine directly the installation time of the support and self-supportability of ground. It should be necessary to perform the additional numerical analysis.

• Journal of the East Asian Society of Dietary Life
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• v.22 no.3
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• pp.414-421
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• 2012

Moisture content of muffin tended to increased as increasing mixing rate of maesangi. For crude protein, sample group of 9% replaced by maesangi powder was the highest. For crude fat and crude ash, there was no significant difference among sample groups. The average height of muffin was 4.7 cm, but was no significant difference among sample groups. Volume of muffin has been gradually increased as increasing mixing rate of maesangi powder, but was no significant difference among sample groups. From the SEM (scanning electron microscope) result, thick cell wall and rough blowholes were appeared. L-, a and b-values of muffin was declined as per increase of mixing rate of maesangi powder. Hardness was inclined as per increase of mixing rate of maesangi powder. There were significant differences between sample groups and reference group for adhesiveness, springiness and cohesiveness, but was no significant difference among sample groups. For gumminess, sample group of 9% replaced by maesangi powder was the highest, but there were no significant difference from sample groups of 3% and 6% replaced by maesangi powder. Chewiness was inclined as per increase of mixing rate of maesangi powder, and sample group of 9% replaced by maesangi powder was the highest. From sensory test result, sample group of 9% replaced by maesangi powder was the highest for color, and there were significant differences among sample groups. Sample group of 6% replaced by maesangi powder was the highest for flavor and taste, and there were significant differences among sample groups. Sample groups of 6% and 9% replaced by maesangi powder were the highest for texture. Sample group of 9% replaced by maesangi powder was the highest for overall preference. From all these results, the most suitable one would be the sample group of 9% replaced by maesangi powder.

• Asian-Australasian Journal of Animal Sciences
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• v.21 no.1
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• pp.120-123
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• 2008

This experiment was conducted to investigate the effect of different nipple angles on water disappearance in growing pigs, which is defined as the water which leaves the watering device but is not consumed by the pig. This water adds to the volume of the total waste slurry. Four crossbred pigs averaging $70.0{\pm}1.4$ kg were assigned into 1 of 4 treatments using a $4{\times}4$ Latin-square design. Treatments were distinguished by the angle between nipple terminal and the perpendicular wall. These angles were: 1) NA-30 (= Nipple Angle $30^{\circ}$), 2) NA-45 (= Nipple Angle $45^{\circ}$), 3) NA-60 (= Nipple Angle $60^{\circ}$) and 4) NA-90 (= Nipple Angle $90^{\circ}$). All of the nipples were fixed at shoulder height of each pig. After a 7-day adaptation period, samples were collected from each pig for 4 days, followed by a day for change-over. Pigs were fed a 0.8 kg diet twice daily at 08:00 and 20:00 and supplied water ad libitum. Throughout the experimental period, pigs in the NA-30 treatment group showed greater water disappearance than other treatments. Water disappearance was the lowest for the NA-60 treatment group (p<0.01). The percentage of water disappearance to the water supply was significantly reduced in the NA-60 treatment group (p<0.01). Water intake was the same for all the treatment groups. The rate of water disappearance per unit of water intake was significantly decreased in pigs in the NA-60 treatment group compared to other groups (p<0.01). These results suggested that the nipple angle for growing pigs should be $60^{\circ}$ to reduce water disappearance and, subsequently, the amount of waste generated.

• Korean Chemical Engineering Research
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• v.49 no.1
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• pp.41-46
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• 2011

We investigated experimentally the properties of dust explosion through lycopodium particle clouds in a duct to provide the fundamental knowledge. Propagating dust flames in the vertical duct of 120 cm height and 12 cm square cross-section were observed by digital video camera and flame front is visualized using by PIV(Particle Image Velocimetry) system. As the result, when the same average dust concentration existed in the vertical duct, downward flame propagation was faster than the upward flame propagation, its rate increased with dust concentration in 300g/$m^3$. Post flames were caused by the ignition of unburned particles which flowed into the rear region of flame from passage between flame and duct wall, and they generated regardless of duct condition. Also, it was found that appearance frequency of post flames during dust flame propagations increased with the increase of dust concentration.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.281-288
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• 1979

For years, physicians and anatomists have been interested in the heart that has one functioning ventricle. Various terms have been suggested for this entity including single ventricle, common ventricle, double-inlet left ventricle, cor biatriatum triloculare, and primitive ventricle. In this report, the term "single ventricle" is utilized as suggested by Van Praagh, and is defined as that congenital cardiac anomaly in which a common or separate atrioventricular valves open into a ventricular chamber from which both great arterial trunks emerge. An outlet chamber, or infundibulum, may or may not be present and give rise to the origin of either of the great arteries. This definition excludes the entity of mitral and tricuspid atresia. An 11 year old cyanotic boy was admitted chief complaints of exertional dyspnea and frequent upper respiratory infection since 2 weeks after birth. He was diagnosed as inoperable cyanotic congenital heart disease, and remained without any corrective treatment up to his age of 11 year when he suffered from aggravation of symptoms and signs of congestive heart failure for 2 months before this admission. On 22nd of May 1979, he was admitted for total corrective operation under the impression of tricuspid atresia suggested by a pediatrician. Physical check revealed deep cyanosis with finger and toe clubbing, and grade V systolic ejection murmur with single second heart sound was audible at the left 3rd intercostal space. Development was moderate in height [135 cm] and weight[28Kg]. Routine lab findings were normal except increased hemoglobin [21.1gm%], hematocrit [64 %], and left axis deviation with left ventricular hypertrophy on EKG. Cardiac catheterization and angiography revealed 1-transposition of aorta, pulmonic valvular stenosis, double inlet of a single ventricle with d-loop, and normal atriovisceral relationship [Type III C solitus according to the classification of Van Praagh]. At operation, longitudinal incision at the outflow tract of right ventricle in between the right coronary artery and its branch [LAD from RCA] revealed high far anterior aortic valve which had fibrous continuity with mitral annulus, and pulmonic valve was stenotic up to 4 mm in diameter positioned posterolaterally to the aorta. Ventricular septum was totally defective, and one markedly hypertrophied moderator band originated from crista supraventricularis was connected down to the imaginary septum of the ventricular cavity as a pseudoseptum of the ventricle. Size of the defect was 3X3 cm2 in total. Patch closure of the defect with a Teflon felt of 3.5 x 4 cm2 was done with interrupted multiple sutures after cut off of the moderator band, which was resutured to the artificial septum after reconstruction of the ventricular septum. Pulmonic valvotomy was done from 4 mm to 11 mm in diameter thru another pulmonary arteriotomy incision, and right ventriculotomy wound was closed reconstructing the right ventricular outflow tract with pericardial autograft of 3 x 4 cm2. Atrial septal defect of 2 cm in diameter was closed with 3-0 Erdeck suture, and atrial wall was sutured also when rectal temperature reached from 24`C to 35.5`C. Complete A-V block was managed with temporary external pacemaker with a pacing rate of 110/min. thru myocardial wire, and arterial blood pressure of 80/50 mmHg was maintained with Isuprel or Dopamine dripping under the CVP of 25-cm saline. Consciousness was recovered one hour after the operation when his blood pressure reached 100 /70 mmHg, but vital signs were not stable, and bleeding from the pericardial drainage and complete anuria were persisted until his heart could not capture the pacemaker impulse, and patient died of low output syndrome 320 min after the operation.

• Journal of Chest Surgery
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• v.12 no.3
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• pp.289-296
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• 1979

For years, physicians and anatomists have been interested in the heart that has one functioning ventricle. Various terms have been suggested for this entity including single ventricle, common ventricle, double-inlet left ventricle, cor biatriatum triloculare, and primitive ventricle. In this report, the term "single ventricle" is utilized as suggested by Van Praagh, and is defined as that congenital cardiac anomaly in which a common or separate atrioventricular valves open into a ventricular chamber from which both great arterial trunks emerge. An outlet chamber, or infundibulum, may or may not be present and give rise to the origin of either of the great arteries. This definition excludes the entity of mitral and tricuspid atresia. An 11 year old cyanotic boy was admitted chief complaints of exertional dyspnea and frequent upper respiratory infection since 2 weeks after birth. He was diagnosed as inoperable cyanotic congenital heart disease, and remained without any corrective treatment up to his age of 11 year when he suffered from aggravation of symptoms and signs of congestive heart failure for 2 months before this admission. On 22nd of May 1979, he was admitted for total corrective operation under the impression of tricuspid atresia suggested by a pediatrician. Physical check revealed deep cyanosis with finger and toe clubbing, and grade V systolic ejection murmur with single second heart sound was audible at the left 3rd intercostal space. Development was moderate in height [135 cm] and weight[28Kg]. Routine lab findings were normal except increased hemoglobin [21.1gm%], hematocrit [64 %], and left axis deviation with left ventricular hypertrophy on EKG. Cardiac catheterization and angiography revealed 1-transposition of aorta, pulmonic valvular stenosis, double inlet of a single ventricle with d-loop, and normal atriovisceral relationship [Type III C solitus according to the classification of Van Praagh]. At operation, longitudinal incision at the outflow tract of right ventricle in between the right coronary artery and its branch [LAD from RCA] revealed high far anterior aortic valve which had fibrous continuity with mitral annulus, and pulmonic valve was stenotic up to 4 mm in diameter positioned posterolaterally to the aorta. Ventricular septum was totally defective, and one markedly hypertrophied moderator band originated from crista supraventricularis was connected down to the imaginary septum of the ventricular cavity as a pseudoseptum of the ventricle. Size of the defect was 3X3 cm2 in total. Patch closure of the defect with a Teflon felt of 3.5 x 4 cm2 was done with interrupted multiple sutures after cut off of the moderator band, which was resutured to the artificial septum after reconstruction of the ventricular septum. Pulmonic valvotomy was done from 4 mm to 11 mm in diameter thru another pulmonary arteriotomy incision, and right ventriculotomy wound was closed reconstructing the right ventricular outflow tract with pericardial autograft of 3 x 4 cm2. Atrial septal defect of 2 cm in diameter was closed with 3-0 Erdeck suture, and atrial wall was sutured also when rectal temperature reached from 24`C to 35.5`C. Complete A-V block was managed with temporary external pacemaker with a pacing rate of 110/min. thru myocardial wire, and arterial blood pressure of 80/50 mmHg was maintained with Isuprel or Dopamine dripping under the CVP of 25-cm saline. Consciousness was recovered one hour after the operation when his blood pressure reached 100 /70 mmHg, but vital signs were not stable, and bleeding from the pericardial drainage and complete anuria were persisted until his heart could not capture the pacemaker impulse, and patient died of low output syndrome 320 min after the operation.

• Journal of Animal Environmental Science
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• v.7 no.3
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• pp.147-154
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• 2001

An experiment was conducted to examine environmental influences upon the behavioral pattern of pigs. The resting areas of an enclosed growing-finishing pig house were checked in two seasonal ventilation systems, and the excretion habit of pigs influenced by the different closing rates (50, 75 and 100%) of side walls of pens was surveyed. 1. The excretion habit of pigs was not influenced by temperature, humidity and the flow speed of running air as they excreted in a fixed area of the side walls. However, the lighting effects on the excretion habit was observed because pigs excreted in the darkest area of the pig pen. 2. The accumulated height and width of feces showed 10 and 30 cm; 5 and 25cm; and 3 and 20cm for 50, 75 and 100% of closing rates of side walls, respectively. It indicates that pigs excrete all over the floor in the pen with 100% closed side walls. 3. Ammonia concentrations of the resting areas on the pen floor were determined to 4.2, 5.1 and $5.8mg/{\ell}$ for 50, 75 and 100% of closing rates of side walls, respectively. It indicates that the ammonia concentration was highest in the pen with 100% closed side walls. Thus, the high ammonia concentration of the resting areas could be reduced by illuminating the darker areas with relation to the excretion habit. 4. The flow speed of running air was likely the biggest factor influencing the resting areas of pigs; pigs took a rest at the place of 0.04 m/s air flow speed point during midwinter, and at the place of 0.24 m/s air flow speed point during midsummer.

• Journal of Periodontal and Implant Science
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• v.37 no.4
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• pp.691-704
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• 2007

Between 1997 May and 2007 May, One hundred and seventeen patients were treated. There were 129 cases of sinus elevation using a lateral window opening procedure and 258 implants placed simultaneously or delayed. The cumulative survival rate of the implants calculated. The implants were evaluated according to surgical site, quality and quantity of bone, graft material, membrane used, the length and diameter of the implant and complications. 1. The 10-year cumulative survival rate of the implants by sinus augmentation using lateral window approach was 96.90%. 2. There was no difference in the survival rate between the implant placed simultaneously with sinus elevation (one stage) and the procedure performed in the delayed procedure (two stage). 3. There was no difference in the survival rate according to the type and amount of graft materials. 4. There was no difference in the survival rate according to the implant site, bone quality and quantity. 5. There was no difference in the survival rate when the $CollaTape^{(R)}$ or Gore-Tex was placed in the window of the lateral wall. 6. There was no difference in the survival rate of the implant length and diameter. 7. The survival rate was as low as 75.00% when there were more than two complications. Implant placement with sinus augmentation using the lateral window approach is a predictable treatment method. Although the vertical height of residual ridge is insufficient and the quality of bone is poor, the normal survival rate of the implants would be expected if an appropriate graft material and membrane is used with greater effort to prevent complications.

• Journal of the Korean Vacuum Society
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• v.20 no.2
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• pp.155-163
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• 2011

Carbon nanotubes (CNT) have been attracted much attention since they have been expected to be used in various areas by virtue of their outstanding physical, electrical, and chemical properties. In order to make full use of their prominent electric conductivity in some areas such as electron emission sources, device interconnects, and electrodes in energy storage devices, direct growth of CNT with vertical alignment is definitely beneficial issue because they can maintain mechanical stability and high conductivity at the interface between substrates. Here, we report direct growth of vertically aligned CNT (VCNT) on Cu foils using thermal chemical vapor deposition and characterize the field emission property of the VCNT. The VCNT's height was controlled by changing the growth temperature, growth time, and catalytic layer thickness. Optimum growth condition was found to be $800^{\circ}C$ for 20 min with acetylene and hydrogen mixtures on Fe catalytic layer of 1 nm thick. The diameter of VCNT grown was smaller than that of usual multi walled CNT. Based on the result of field emission characterization, we concluded that the VCNT on Cu foils can be useful in various potential applications where high conductivity through the interface between CNT and substrate is required.