• Asian Pacific Journal of Cancer Prevention
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• v.16 no.11
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• pp.4577-4581
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• 2015

Background: To explore the hospitalizations of breast cancer patients undergoing mastectomy, and to provide a basis for management, clinical prevention and treatment. Materials and Methods: We conducted an investigation by means of the retrospective survey and the medical records retrieval system, and made out the data of patients suffered from breast cancer in a hospital in Guangzhou from 2004 to 2013, including age, medical payment methods, pathological type, treatment, treatment results, complications, hospitalization days, cost and so on. Results: The average age of the inpatients was 50.14 years old. The main histologic types were infiltrating duct carcinoma (88.06%). The main surgery was modified radical mastectomy (80.41%). The cure rate was 90.80% during the 10 years. The main medical payment method was self-paying (57.28%). The average hospital stay was 13.51 days, and average hospitalization cost was RMB 23,083.66 yuan, proportion of drug fees up to 39.70%. Postoperative complication rate was 0.79%. The self-paying group was with the highest proportion of drug fees (P<0.05), while the free medical service group was with the longest hospitalization days (P<0.05). Conclusions: The payment methods significantly affected the proportion of drug fees and hospitalization days. The therapeutic effect was satisfactory with less complications and reasonable proportion of drug fees in our hospital.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.19 no.2
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• pp.24-29
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• 2020

In South Korea, agricultural mechanization has been carried out in paddy field, but not in the upland field during recent decades. Among crops such as root vegetables, leafy vegetables from upland field, corn is used as forage for livestock as well as food for men. The corn harvester needs to be developed to replace men's labor in rural area to follow the recent needs in the farm industry. The corn harvester is comprised of three parts such as cutting part, feeding part and pick-up part. The feeding part is so long for cut corns to be delivered from the cutting part to the pick-up part. Structurally, the load from the long moment arm is likely to be big. Thus, the setup to measure the stress on the duct of the feeding part was configured with the data acquisition system. The strain gages were attached on several points that seem to be loaded a lot comparatively. The stress was measured and the measured stresses were divided by the yield stress to get the safety factor. And then, we made sure the safety factors were above 1 on the all points. In conclusion, the feeding part of the corn harvester which convey the cut corn from the cutting part from the pick-up part can be regarded to be made safe structurally.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.40 no.7
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• pp.574-581
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• 2012

Because of the exposed blade, the UAV using the rotors entail the risks during operation. While a wrapped duct around the fan blades reduces risks, it is a higher thrust performance than the same power load rotor. In this paper, for applying advantages of a ducted fan, the tri-ducted fan air vehicle configuration is proposed. The vehicle has three ducted fans. Two of them are the same shape and size and the third one is the smaller. It is possible to control a rapid attitude stability using thrust vector control. The equations of motion of the tri-ducted fan were derived. Lyapunov control input was applied to the system and stable inputs were derived. A nonlinear simulation was fulfilled by using parameters of a prototype vehicle. It verified a stable attitude and analyzed results.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.9
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• pp.1253-1262
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• 2001

Experimental study is conducted to investigate the heat/mass transfer and flow characteristics for the flow over backward-facing step and cavities. A naphthalene sublimation method has been employed to measure the mass transfer coefficients on the duct wall and LDV system has been used to obtain mean velocity profiles and turbulence intensities. Reynolds number based on the step height and free stream velocity is 20,000 and St numbers of acoustic excitations given to separated flow are 0.2 to 0.4. The spectra of streamwise velocity fluctuation show a sharp peak forcing frequency for an acoustically excited flow. The results reveal that the vortex pairing and overall turbulence level are enhanced by the acoustic excitation and a significant decrease in the reattachment length and the increased turbulence intensity are observed with the excitation. A certain acoustic excitation increases considerably the heat/mass transfer coefficient at the reattachment point and in the recirculation region. For the cavities, heat/mass transfer is enhanced by the acoustic excitation due to the elevated turbulence intensity. For the 10H cavity, the flow pattern is significantly changed with the acoustic excitation. However, for the 5H cavity, the acoustic excitation has little effect on the flow pattern in the cavity.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.4
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• pp.76-82
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• 2018

Grout in duct is very effective protection from tendon corrosion in PSC(Prestressed Concrete) structure. In the work, durability and mechanical tests are performed for two types of grout which are conventionally used one and the improved grout with reduced w/c (water to cement) ratio and silica fume. Tendon system with 1000mm height is prepared and various tests including strength, flow, absorption, and bleeding ratio are conducted. ICM(Impressed Current Method) is adopted for corrosion acceleration in tendon with 12.7mm diameter inside grout. For 2 and 4 days, corrosion acceleration is performed for 2 different type of grout and corrosion amount is investigated. The improved grout shows higher compressive strength by 10 MPa and lower absorption ratio by 50% than the conventional one. It also provides an excellent corrosion reduction to 39.8 %~48.2 % for 2~4 days of acceleration period.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.3
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• pp.234-236
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• 2011

Traditional surgery to remove foreign bodies in the face carries a risk of postoperative morbidity with an injury to various anatomical structures, particularly the facial nerve and parotid duct and gland. Endoscopy can be a great aid in the removal of foreign bodies in the maxillofacial region. Surgical intervention using endoscope and/,or intraoperative images can be minimized, allowing the safe and precise removal of foreign bodies, and saving operating time. We report a case of the use of an endoscope and C-arm fluoroscopy guidance system to remove a very small foreign body.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.11
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• pp.751-760
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• 2007

Baffles enhance heat transfer by disturbing boundary layer and bulk flow, creating impingement, and increasing heat transfer surface area. This study was performed to determine how the two inclined baffles (${\alpha}=5^{\circ}$ perforated models) placed at a rectangular channel affect heat transfer and associated friction characteristics. The parametric effects of perforated baffles (3, 6 and 12 holes) and flow Reynolds number ranging from 28,900 to 61,800 on the heated target surface are explored. Comparisons of the experimental data with the numerical results by commercial code CFX 10.0 are presented. As for the investigation of heat transfer behaviors on local Nusselt number with two baffles placed at $x/D_h=0.8$ and $x/D_h=8.0$ of the edge of baffles, it is evident that the inclined perforated baffles augment overall heat transfer significantly by both jet impingement and boundary layer separation. There exists an optimum perforation density to maximize heat transfer coefficients; i.e., the average Nusselt number increases with increasing number of holes, but the friction factor decreases with an increase in the hole number placed at baffles.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.2
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• pp.318-328
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• 1991

The present paper describes the experimental study on the fixed-type wave-energy conversion system, consisting of the OWC-type wave-energy absorbing chamber and the duct for the air turbine. For simplicity, a screen of wire mesh was employed in place of an air turbine in order to simulate its effects on OWC chamber. Experiments were performed at the towing tank in regular waves with the frequency range of 0.22-0.75Hz. Comparison wish the numerical prediction using a potential flow-based method [4] was made to validate the capability of numerical code. It was shown that the agreements between measured and calculated results are quite good, giving a confidence in prediction method. Simulation of air turbine using a wire-mesh screen was successful, at least in a qualitative sense, to investigate the inter action between the OWC chamber and an air turbine. Results also showed that the effects of a wire-mesh screen on chamber efficiency are negligible, and the present model can be effectively utilized for the practical use in ocean waves with the frequency range under 0.3Hz.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.20 no.11
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• pp.760-766
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• 2008

The characteristics of heat transfer and pressure drop of several different porous materials which can be used as inserts inside solar volumetric air receivers were experimentally investigated. Generally, porous materials were inserted into solar volumetric air receivers to increase the thermal performance. In the present work, honeycomb (diameter: 100 mm, thickness: 30 mm), laminated mesh (diameter: 100 mm, thickness: 1 mm) are considered as the inserts for the experiment. The experimental apparatus consists mainly of a cylindrical ceramic duct as a receiver and an electric heater as an energy source. This system is an intake open loop, which used as air of working fluid. The temperatures inside the ceramic tube are measured by thermocouples, which are installed at each layer of the porous materials. The pressure-drop experimental apparatus is fabricated alike the above experimental equipment. An acrylic tube is used like as the ceramic tube, which has the same specifications of the ceramic tube. The pressure drop of porous materials inserted in the acrylic tube is measured between front and rear of those by transmitter. The results show that the laminated mesh surpasses the honeycomb of heat transfer and pressure drop increase as the porous material thickness and Reynolds number.

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.5
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• pp.999-1003
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• 1992

Because of low noise and small size with huge capacity, a centrifugal fan is widely used for ventilation, air-conditioner and so on, which are very near to human life. Because of the complexity of its vibration and noise generation mechanics, most of researches on them are based on experimental methods. This study is to characterize the centrifugal fan noise and vibration. It is considered that noise is composed of the structural vibration noise and the air flow induced aerodynamic noise. To decouple the structural vibration noise the centrifugal fan is masked with an adhesive tape, such that air blowing is prohibited thus only the structural vibration noise is extracted. The noise level and characteristics in the frequency domain are verified and compared with those of total mixed one. This study shows some significant results that the structural vibration noise has relatively narrow band power spectrum compared with the total mixed one and has a strong periodicity. The sound level is lowered about 5dB by the removal of air flow with the masked fan for an air-conditioner used in this study.