• Advances in pediatric surgery
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• 제14권1호
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• pp.67-74
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• 2008

The usefulness of totally implantable central venous port for long-term intravenous infusion is widely accepted in children. Usually the catheters are placed through the internal or external jugular vein. In case of jugular vein cut-down, two separate incisions are needed for catheter and port respectively. Patients also feel uncomfortable as the catheter run through the neck. However these disadvantages can be overcome by using the cephalic vein (CV). We reviewed our experiences on CV cut-down for totally implantable central venous port in children. From January 2002 to December 2006, 201 patients (M:F=127:74) underwent 218 central venous port insertions. Mean age at operation was 5.9 years (2 months - 19 years). Indications included chemotherapy (N=167), long-term intravenous antibiotics infusion (N=36), and total parenteral nutrition (N=15). CV was selected preferentially. The incision includes the deltopectoral triangle laterally, and both the CV cut-down and port insertion were achieved with a single incision. The number of insertion through external, internal jugular vein, and CV was 77, 66 and 75, respectively. The median age, height and body weight were higher in CV cut-down group. The youngest age for CV cut-down was 8 months, the shortest height was 69 cm and the smallest body weight was 5.9 kg. Of 118 trials of CV cut-down, cut-down was successful in 75 cases (63.6 %). CV was absent in 10 cases(8.4 %) and CV was sacrificed after catheter tip malposition in 10 cases (8.4 %). There was only one complication, in which the catheter was inserted into the minute branch of subclavian artery. The CV cut-down method for totally implantable central venous port was safe and feasible in selected groups of patients in children. In addition, preservation of jugular vein and a more favorable cosmetic effect are other benefits of CV cut-down.

• 한국잠사곤충학회지
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• 제4권
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• pp.27-31
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• 1965

춘기발아전에 지조를 각각 선단벌채, 조장의 1/3, $\frac{1}{2}$, 2/3 벌채하여 발아 생장하는 신아의 발육상황을 조사하였다. (1) 지조를 벌채하면 불발아비율이 대체적으로 감소하여 무처리구의 반이하로 되는 것인데 1/3 벌채구가 가장 그 비율이 적어진다. 그리고 또 지조를 벌채하면 불발아는 지조의 하반부에 집중한다. (2) 지조를 벌채하여도 발아를 촉진시키는 일은 없고 도리어 약간 늦어지는 경향이 있는 것 같지마는 발아후의 개엽속도는 매우 빨라져서 탈순에서부터 제 5개엽기까지의 소요일수는 무처리구의 16일에 비하여 벌채 각구는 7~9일이며 그 중 가장 빠른 것은 2/3벌채구의 7일이다. (3) 지조를 벌채하면 신아의 발육을 촉진시켜서 5월 5일부터 6월 10일까지 45일간의 생장량이 무처리구의 34cm에 비하여 벌채각구는 그 1.6~2.5배나 생장하여 가장 생장량이 큰 것이 2/3벌채구의 83cm이다. 그리고 벌채각구는 생장속도도 무처리구에 비하여 빠르다. (4) 엽수의 증가비율은 무처리구에 비하여 벌채각구가 약간 많기는 하지만 그 차는 그리 크지 않다. (5) 신아의 총생장량은 무처리구에 비하여 벌채각구가 현저하게 많으며 2/3벌채구는 생장계적아수가 벌채각구중에서 가장 적지만은 1아의 평균아장이 가장 길다. (6) 신소삽목의 삽수를 되도록 빨리 채취하기 위해서는 조장의 2/3정도를 벌채하는 것이 적당할 것 같다.

• International Journal of Precision Engineering and Manufacturing
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• 제4권3호
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• pp.62-67
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• 2003

The grinding force generated during the grinding process causes an elastic deformation of the workpiece, grinding wheel, and machine system. Thus, the true depth of cut is always smaller than the apparent depth of cut. This is known as machining elasticity phenomenon. The machining elasticity parameter is defined as a ratio between the true depth of cut and the apparent depth of cut. It is an important factor to understand the material removal mechanism of the grinding process. To increase productivity, the value of this machining elasticity parameter must be large. Therefore, it is essential to know the characteristics of this parameter. The objective of this research is to study the effect of the major grinding conditions, such as table speed, depth of cut, on this parameter experimentally, Through this research, it is found that this parameter value is increasing when the table speed is decreasing or the depth of cut is increasing. Also, this parameter value depends on the grinding mode (up grinding, down grinding).

• 한국정밀공학회지
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• 제16권4호통권97호
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• pp.220-228
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• 1999

The machining accuracy has been improved with the development of NC machine tools and cutting tools. However, it is difficult to obtain a high degree of accuracy when machining deep pocket with long end mill, since machining accuracy is mainly dependant on the stiffness of the cutting tool. To improve surface accuracy in machining deep pocket using end mill, the performance by down cut and up cut is compared theoretically and experimentally. To verify usefulness of up milling, various experiments were carried out. As a result, it is found that up milling produce more accurate surface than down milling in machining deep pocket. For effective application of up milling, various values in helix angle, number of teeth, radial depth of cut and axial depth of cut are applied in experiment.

• 한국정밀공학회지
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• 제15권8호
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• pp.26-32
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• 1998

The grinding force generated during the grinding process causes an elastic deformation of the workpiece, grinding wheel, and machine system. Thus, the true depth of cut is always smaller than the apparent depth of cut. This is known as machining elasticity phenomenon. The machining elasticity parameter is defined as a ratio between the true depth of cut and the apparent depth of cut. It is an important factor to understand the material removal mechanism of the grinding process. To increase productivity, the value of this machining elasticity parameter must be large. Therefore, it is essential to know the characteristics of this parameter. The objective of this research is to study the effect of the major grinding conditions, such as table speed and depth of cut, on this parameter experimentally. Through this research, it is found that this parameter value is increasing when the table speed is decreasing or the depth of cut is increasing. Also, this parameter value depends on the grinding mode (up grinding, down grinding).

• 한국환경과학회지
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• 제12권3호
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• pp.345-358
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• 2003

Jindong bay at the northwestern part of Jinhae bay suffers from the occurrence of red tides in summer every year. In order to study the management methods of coastal environments, an ecological numerical model has been developed. The model experiments was forecasted that the load of nutrients from the land and field concentration will be cut down per 10% each. When we cut down 57.2% nitrogen load in the inner bay and 38.4% phosphorous load in the outer bay of bottom layer of the nutrients load from land and field concentration, the seawater quality standard levels up first grade. When we cut down 86.5% nutrients in the inner bay and 93.0% nutrients in the outer bay, the concentration of chlorophyll a decreases below 3.2 $\mu\textrm{g}$/(equation omitted)(an individual concentration of phytoplankton : 10,000cel1/ml), i.e. the red tides do not occur.

• 대한안전경영과학회지
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• 제7권2호
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• pp.95-106
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• 2005

Many Korean companies are challenged to reduce logistics cost and meet environmental-friendly logistics. The textile companies in harsh competition are requested to make improvement on their logistics environment to cut down the total cost. However, they have reached the limit on improving the manufacturing process. We believe that the logistics department is the most improvable part at present. Improving logistics will be highly effective to cut down the total cost. In this study, we present Pad Pool System(PPS) as the solution to save their logistics cost. PPS, which means the shared use of Styrofoam pads, will enable the textile companies to cut down their cost and strengthen enterprise competitiveness. Also, PPS will be helpful reducing environmental disruption because the system reuses retrieved Styrofoam pads many times.

• 한국정밀공학회지
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• 제15권6호
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• pp.58-63
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• 1998

There are lots of factors that are related to the geometric characteristics of machined surface. Among them, the tool path and milling mode (up cut milling or down cut milling) are the easiest controllable machining conditions. Thus, the first objective of this research is to study the effects of them on the milled surface that is generated by an end milling tool. To get precision parts, not only the machining process but also the measurement of geometric tolerance is important. But, this measurement requires a lot of time, because the infinite surface points must be measured in the ideal case. So, the second objective is to propose a simple flatness measurement method that can be available instead of the 3-D geometric tolerance measurement method, using a scale factor and characterized points. Finally, it is also shown that the possibility of flatness improvement by shifting the consecutive fine cutting tool path as compared with the last rough cutting tool path.

• 화약ㆍ발파
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• 제20권2호
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• pp.7-19
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• 2002

The cut is placed high up in the section, the 1st sloping holes below the cut, and divided all the holes located below the 1st sloping holes into a certain area with longitudinal section, to lower pollution made from tunnel blasting. With the sequential blasting machine, after I first blasted holes around the cut holes by a pre-splitting method, blasted the cut area and the 1st sloping holes. The 1st and 2nd sloping holes divided areas are initiated gradually to free face upwards made by the cut. Especially, I pre-splinted contour holes previous blast the before sloping holes from the contours. The ground vibration from the earth surface just over the advance face decreased about 42.0% compare with the down blasting method under the condition of equal charge weight per delay. I controlled the crack and over break of the mother rock by pre-splitting contour holes before blast the first sloping holes from the contours. The peak values of noise and air blast by blasting decreased about 10dB more than the down blasting method. the noise and air blast diminished gradually as a round. The throw distance of the fly rock was decreased about 55%.

• Nuclear Engineering and Technology
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• 제50권6호
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• pp.854-859
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• 2018

Calculating minimal cut sets is a typical quantification method used to evaluate the top event probability for a fault tree. If minimal cut sets cannot be calculated or if the accuracy of the quantification result is in doubt, the Monte Carlo method can provide an alternative for fault tree quantification. The Monte Carlo method for fault tree quantification tends to take a long time because it repeats the calculation for a large number of samples. Herein, proposal is made to improve the quantification algorithm of a fault tree with circular logic. We developed a top-down iteration algorithm that combines the characteristics of the top-down approach and the iteration approach, thereby reducing the computation time of the Monte Carlo method.