• The Journal of Advanced Prosthodontics
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• v.15 no.3
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• pp.101-113
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• 2023

PURPOSE. This randomized controlled trial aimed to evaluate the effect of implants' two different diameters and cantilever lengths on the marginal bone loss and stability of mplants supporting maxillary prostheses. MATERIALS AND METHODS. Ninety-six implants were placed in sixteen completely edentulous maxillary ridges. Patients were randomly divided into two groups: Group A, implants were placed with a cantilever to anterior-posterior AP spread length (CL:AP) at a ratio of 1:3; Group B, implants were placed with a CL:AP at a ratio of 1:2. Patients were further divided into four sub-groups: Groups A1, A2, B1, and B2. Groups A1 and B1 received small diameter implants while Groups A2 and B2 received standard diameter implants. Bone height and stability measurements around each implant were performed at 0, 4, 8 and 24 months after definitive prostheses delivery. RESULTS. Statistical analysis of the mean implant stability and height values revealed an insignificant difference between Group A1 and Group A2 at all the different time intervals while significantly higher values in Group B1 in comparison with Group B2. Results also showed significantly higher values in Group A1 in comparison with Group B1 and an insignificant difference between Group A2 and Group B2 at all the different time intervals. CONCLUSION. It can be concluded that the use of small diameter implants placed with a CL:AP at a ratio of 1:3 provided predictable results and that the 1:2 CL:AP significantly induced more critical bone loss in the small diameter implants group, which can significantly reduce long term success and survival of implants

• Smart Structures and Systems
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• v.1 no.1
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• pp.47-61
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• 2005

A ring-shaped lead zirconate titanate (PZT) piezoceramic sensor has been integrated with the Langevin-type piezoceramic driver of an ultrasonic wire-bonding transducer to form a smart transducer for in-situ measurement of three essential bonding parameters: namely, impact force, ultrasonic amplitude and bond time. This sensor has an inner diameter, an outer diameter and a thickness of 12.7 mm, 5.1 mm and 0.6 mm, respectively. It has a specifically designed electrode pattern on the two major surfaces perpendicular to its thickness along which polarization is induced. The process-test results have indicated that the sensor not only is sensitive to excessive impact forces exerted on the devices to be bonded but also can track changes in the ultrasonic amplitude proficiently during bonding. Good correlation between the sensor outputs and the bond quality has been established. This smart transducer has good potential to be used in automatic process-control systems for ultrasonic wire bonding.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.6
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• pp.1689-1699
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• 1990

Sendzimir rolling mill is widely used for rolling hard materials such as stainless steel due to its small work roll diameter and shape controllability using two effective actuators, AS-U-Roll crown adjustment and lst. intermediate roll shifting. However, in comparison with 4-high or 6-high mills, it is noteasy to get good strip or excellent flatness because Z-mill has small diameter of work rolls which are easily deformed by load. A new mathematical model based on the method of dividing roll and strip into multo-portions was used to develop strip profile prediction software. Using the developed software, several influencing factors related to rolled strip profile for Z-Mill were tested analytically and characterized for the effective shape control. The effects of adjusting shape control actuators of Z-Mill on strip profile were also examined and discussed in detail.

• Journal of Bio-Environment Control
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• v.13 no.3
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• pp.130-134
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• 2004

Experiments were conducted to evaluate quality and vase life of cut rose ‘Rote Rose’ cultivated either in soil or hydroponically in rockwool. Rose stems were put in four different preservative solutions, 0.5% chrysal RVB, BS (2% sucrose + 200 mg. L$^{-1}$ 8HQS + 0.3% Chrysal RVB), Sonk1 (BS + 0.1 mM ethionine), and double distilled $H_2O$. Flower stems were displayed at $20\pm1^{\circ}C$, RH 60%, and light intensity of $8.1\mu$mol.$m^{-2}$ .$s^{-1}$ provided by fluorescent lamps for 16 hㆍ$d^{-1}$ Fresh weight and flower diameter during vase life were affected by cultivation method and were greater in hydroponically-grown roses than in soil-grown roses. Among preservative solutions, BS and Sonkl were superior to Chrysal RVB in terms of extending vase life. Vase life of cut rose in Chrysal RVB, BS, and Sonkl over the control was prolonged by about one day.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.8
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• pp.813-821
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• 2015

In this paper, we analyzed the problems of a batch-type sterilizer and design a continuous sterilizer to control the temperature deviation. The temperature deviation is analyzed with respect to design parameters such as a nozzle diameter, hole diameter, and nozzle length. The significant temperature parameters are optimized using the response surface methodology. An experimental apparatus is developed using the optimized design parameters. Using a field test, we show that the target temperature is obtained in about 7.3 minutes and the temperature deviation is improved about $0.84^{\circ}C$. The optimized parameters from the test are equal to the analytical parameters.

• Tribology and Lubricants
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• v.13 no.3
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• pp.63-72
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• 1997

The stability of a rotor-bearing system supported by swirl-controlled hybrid journal bearing with pair-type angled injection orifices is investigated for improvement of the whirl frequency ratio by allowing effective control of the tangential flow inside the bearing clearance, i.e., by achieving more freedom in controlling strength and direction of the supply tangential flow inside the bearing clearance. It is suggested that the system instability can be improved through the change of bearing dynamic characteristic parameters with the swirl control. The orifice diameter $d_0$ and recess injection angle $\alpha$ along with combinations of swirl/anti-swirl supply pressures and directions (3.0~3.0 MPa, 4.0~2.0 MPa, 2.0~4.0 MPa) are selected for design parameters for swirl-controlled effective factors dependent on journal speeds (3000, 9000, 15000, 21000 rpm). It has been found that the orifice diameter $d_0$ shows strong effects on effective maneuverability of direct-stiffness and direct damping values, while recess injection angle $\alpha$ results in substantial effects on the magnitude and direction of cross-stiffness. Specifically, recess injection parameters which are functions of angle of orifice feeding flow and recess dimensions showed very feasible effect on the stability control of swirl-controlled rotor-bearing system.

• Journal of Biosystems Engineering
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• v.17 no.1
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• pp.45-54
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• 1992

A wireless control system was designed and constructed to control the rice transplanter of walking type with remote control. VHF(very high freqency) was sent from wireless transmitter to wireless reciever by usig 6 channels to control main clutch, steering clutch, plant lever and throttle lever within 200 meter distance between remote control and rice transplanter. The rice transplanter with wireless control system showed good performance for accuracy of travel speed, traveling mobility and turning diameter in the concrete, paddy and dry field. It is concluded that the developed wireless control system could be adapted to control not only conventional rice transplanters but also most of the agricultural machine by changing some parts of the control system.

• Journal of Sasang Constitutional Medicine
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• v.13 no.2
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• pp.165-176
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• 2001

This study demonstrates the effects of Yanggyuksanhwa-Tang, Sasang constitutional herb prescription reported its clinical effect on the stroke of the So-yang In(少陽人), on the cerebral blood flow changes induced by nitro L-arginine methyl ester (L-NAME) treatment and ischemic brain damage induced by the middle cerebral artery occlusion (MCAO) in the rats. The changes of the arterial blood pressure, cerebral blood flow, and the diameter of the pial artery were measured in rats treated with L-NAME. And the changes of the infarct size, volume, and plasma tumor necrosis factor alpha ($TNF-{\alpha}$) levels were measured in the rats that the middle cerebral artery has been occluded by the intraluminal suture thread method. Yanggyuksanhwa-Tang was administered by the i.v. injection on the L-NAME treated rats, by the i.o. administration on the MCAO rats. The results is 1. The changes of the arterial blood pressure was not different statistically between in the L-NAME treated control group and in the Yanggyuksanhwa-Tang administered group. 2. Increase in the cerebral blood flow induced by L-NAME treatment was attenuated in the Yanggyuksanhwa-Tang administered group significantly (P<0.05) as compared with the L-NAME treated control group. 3. Decrease in the diameter of the pial artery induced by L-NAME treatment was attenuated about 18% in the Yanggyuksanhwa-Tang administered group as compared with the L-NAME treated control group. 4. Ischemic damaged infarct areas were decreased significantly (P<0.05) in the interaural 12mm, 10mm, and 6mm brain sections of the Yanggyuksanhwa-Tang administered group as compared the MCA occluded control group. 5. Total ischemic infarct volume was decreased significantly (P<0.05) in the Yanggyuksanhwa-Tang administered group as compared the MCA occluded control group. 6. Plasma $TNF-{\alpha}$ levels were decreased significantly (P<0.01) in the Yanggyuksanhwa-Tang administered group as compared the MCA occluded control group.

• Journal of Korean Neurosurgical Society
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• v.59 no.6
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• pp.564-569
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• 2016

Objective : This study used the intradural procedural time to assess the overall technical difficulty involved in surgically clipping an unruptured middle cerebral artery (MCA) aneurysm via a pterional or superciliary approach. The clinical and radiological variables affecting the intradural procedural time were investigated, and the intradural procedural time compared between a superciliary keyhole approach and a pterional approach. Methods : During a 5.5-year period, patients with a single MCA aneurysm were enrolled in this retrospective study. The selection criteria for a superciliary keyhole approach included : 1) maximum diameter of the unruptured MCA aneurysm <15 mm, 2) neck diameter of the MCA aneurysm <10 mm, and 3) aneurysm location involving the sphenoidal or horizontal segment of MCA (M1) segment and MCA bifurcation, excluding aneurysms distal to the MCA genu. Meanwhile, the control comparison group included patients with the same selection criteria as for a superciliary approach, yet who preferred a pterional approach to avoid a postoperative facial wound or due to preoperative skin trouble in the supraorbital area. To determine the variables affecting the intradural procedural time, a multiple regression analysis was performed using such data as the patient age and gender, maximum aneurysm diameter, aneurysm neck diameter, and length of the pre-aneurysm M1 segment. In addition, the intradural procedural times were compared between the superciliary and pterional patient groups, along with the other variables. Results : A total of 160 patients underwent a superciliary (n=124) or pterional (n=36) approach for an unruptured MCA aneurysm. In the multiple regression analysis, an increase in the diameter of the aneurysm neck (p<0.001) was identified as a statistically significant factor increasing the intradural procedural time. A Pearson correlation analysis also showed a positive correlation (r=0.340) between the neck diameter and the intradural procedural time. When comparing the superciliary and pterional groups, no statistically significant between-group difference was found in terms of the intradural procedural time reflecting the technical difficulty (mean${\pm}$standard deviation : $29.8{\pm}13.0min$ versus $27.7{\pm}9.6min$). Conclusion : A superciliary keyhole approach can be a useful alternative to a pterional approach for an unruptured MCA aneurysm with a maximum diameter <15 mm and neck diameter <10 mm, representing no more of a technical challenge. For both surgical approaches, the technical difficulty increases along with the neck diameter of the MCA aneurysm.

• Journal of the Korean Society for Precision Engineering
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• v.3 no.3
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• pp.30-39
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• 1986

The burr worsens the accuracy of a workpiece and decreases a lot of pro- ductivity because it takes so much time and efforts to remove it. In this paper, the height, thickness and size of a drilling burr were derived from the drilling variables of drill diameter, chisel edge angle, web rate =($\Frac{2{\times}\;web\;thickness}{drill\;dia}$) and yielding stress of the workpiece as wel as feed, point angle and helix angle. The theoretical and experimental values of drilling thrust, torque and burr size of the testpiece were analyzed with the method of numerical analysis in a standard drilling condition. The order of choosing the drilling variables for the purpose of controlling the burr size was dealt in this paper with burr forming ratio. The results are as follows: (1) The drill diameter forms 42 percents feed 25 percents point angle 23 percents and web rate, chisel edge angle and gelix angle 5 percents of the partial differential slope of drilling thrust within the usual available ranges of drilling variables. (2) The drill diameter forms 55 percents feed 26 percents web rate 9 percents and chisel edge angle, point angle and helix angle 10 percents of the par- tial differential slope of drilling torque in the usual available ranges of drilling variables. (3) About 70 percents of the burr size can be controlled by feed, 29 percents by web rate in the case of a fixed diameter. It is recommended drilling10 variables to be chosen in the order of feed, web rate, drill diameter, point angle, chisel edge angle and helix angle so as to control the burr size effectively.