• Journal of Mushroom
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• v.4 no.4
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• pp.129-134
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• 2006

In order to make the objective quality standard of Pleurotus eryngii, we statistically analysed fruit body collected by the type of market with our own mushroom research lab's quality standard and suggested the quality standard of Pleurotus eryngii by grade. Namely, premium(extra large), first(large), second(middle), and third grade(small) fruit body were 120~130, 110~120 below, 80~110below, and 80mm and below, respectively in height. The diameters of stipe of each grades were 40~45, 30~40below, 25~30below, 25mm below, respectively. The standard of the diameter of pileus indicated ratio of the diameter of pileus/the diameter of stipe instead of the diameter of pileus only because a quality is depend on a ratio of pileus/stipe. The premium and first grade of a ratio of pileus/stipe were 1.6 below and 1.7and below respectively. The weights of premium(extra large), first(large), second(middle), and third grade(small) fruit body were 95~120, 70~95below, 50~70below, 50g below, respectively.

• Clinical and Experimental Reproductive Medicine
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• v.15 no.2
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• pp.135-147
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• 1988

To compare the stimulation effect of the ratio in follicle stimulating hormone and luteinizing hormone in induction of multiple follicular growth, the serum $E_2$ level, the diameter of follicle, number of aspirated follicles and cleavage rate of in vitro fertilized preovulatory oocytes as well as the pregnancy rate were evaluated. Forty one patients with irreparable tubal disease were stimulated by hMG(n=24) or FSH/hMG(n=17) for the purpose of in vitro fertilization and embryo transfer. The following results were obtained. 1. Serum estradiol($E_2$) levels on the day of hCG administration were $921.0{\pm}353.3\;pg/ml$ in hMG group and $1272.9{\pm}1060.6\;pg/ml$ in FSH/hMG group. The serum $E_2$ value of hMG group was significantly lower than that of FSH/hMG group. 2. The diameter of leading follicle by ultrasonogram on the day of hCG administration were $16.2{\pm}2.0\;mm$ in hMG group and $16.2{\pm}2.6\;mm$ in FSH/hMG group. No significant difference of follicle diameter between two groups was demonstrated. 3. The number of follicles with diameter above 10 mm by sonogram on the day of hCG injection were $3.91{\pm}2.32$ in hMG group and $6.52{\pm}3.86$ in FSH/hMG group. There was significant difference of number of follicles between two groups, (p< 0.01). 4. The number of oocytes found per patient at aspiration were $2.59{\pm}1.00$ in hMG group and 3. $76{\pm}2.31$ in FSH/hMG group. There was significant difference of number of aspirated oocytes between two groups. (p< 0.05). 5. The detection rate of preovulatory oocyte at aspiration were 68.4%(39/57) in hMG group (n=22) and 77.6%(38/49) in FSH/hMG group (n=13). 6. The cleavage rate of preovulatory oocyte at 44 hours after insemination were 74.4%(29/39) in hMG group(n=22) and 81.6%(31/38) in FSH/hMG group (n=13). When only hMG was used, one pregnancy was established in 15 patients to whom 29 zygotes were transferred. And a full term normal female baby was delivered by elective cesarean section. In the FSH/hMG group, five pregnancies out of 9 transferred patients were confirmed by serum ${\beta}-hCG$. Two pregnancies were spontaneously aborted before the 6th week of pregnancy. One patient aborted her baby at the 18th week of pregnancy because of incompetent internal os of the cervix. Two patients delivered two full term babies by elective cesarean section. From the above findings, paralell with the increase in the ratio of exogenous follicle stimulating hormone to luteinizing hormone, an increase in oocyte recovery was observed as well as an improvements in pregnancy rate. It was concluded that FSH enrichment early in the follicular phase had a beneficial effect in the controlled ovarian hyperstimulation.

• Journal of the Korean Society of Propulsion Engineers
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• v.16 no.3
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• pp.69-76
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• 2012

An achieving method of highly progressive pressure gradient is presented to enhance the missile ejection system's performance by using a gas generator in the condition of preventing erosive burning. To obtain and confirm a stable burning, a ground burning test was performed to evaluate the new methods of a radial-hole and a multi-row propellant grain. The test results show that a radial-hole grain takes good effect on erosive burning and not on ejection performance. On the other hand, a multi-row grain which reduces the length-to-diameter ratio(L/D) of grain is very effective to prevent the erosive burning and to enhance the ejection performance simultaneously.

• Journal of Environmental Science International
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• v.22 no.11
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• pp.1481-1498
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• 2013

The SCR (selective catalytic reduction) system is highly-effective technique for NOx reduction from exhaust gases. In this study, the effects of the direction and size of nozzle and the ammonia injection concentration on the performance of SCR system are analyzed by using the computational fluid dynamics method. When the nozzle is arranged in zigzaged direction which is normal to exhausted gas flow, it is shown that the uniformity of gas flow and the NH3/NO molar ratio is improved remarkably. With the change of the ammonia injection concentration from 0.2 vol%(wet) to 1.0 vol%(wet), the uniformity of gas flow shows a good results. As the size of nozzle diameter changes from 6 mm to 12 mm, the uniformity of gas flow is maintained well. It is shown that the uniformity of the $NH_3/NO$ molar ratio becomes better with decreasing the ammonia injection concentration and the size of nozzle diameter.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.20 no.8
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• pp.2721-2730
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• 1996

The present study conducted experimental study of spray combustion to investigate the effect of the inlet conditions of fuel and air on the flame structure, the flame stability and the characteristics of emission in the can-type model of a gas turbine combustor. In the experiment, the diameter of fuel droplet was measured using Malvern particle size analyser and temperatures in the combustion chamber were measured with R-type shielded thermocouple. In addition, flame structure was taken picture with camera and analysed. Gas analyser was also used to analyse the concentration of each components of exhausting gas. The experimental results showed that the flame condition was optimal with swirl number, 0.63 and equivalence ratio, 0.5 for controlling the flame stability, the combustion temperature and the NOx concentration. The present study concluded that both the flame structure and the emission formation were strongly affected by the swirl intensity, which selection was found as an important parameter for either stabilizing flame or lowering the quantity of NOx.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.165-168
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• 2008

A numerical analysis was conducted to predict the heat transfer characteristics of a solar receiver which is subject to very high heat fluxes and temperatures for solar thermal applications. The concentration ratio of the solar receiver ranges 1000 and the concentrated heat is required to be transported to a certain distance for specific applications. This study deals with a solar receiver according to internal geometry variation incorporating high-temperature heat pipe. The isothermal characteristics in the receiver section is of major concern. The diameter of the solar thermal receiver was 120 mm and the length was 400 mm and the angle of receiver end wall set $90^{\circ},\;60^{\circ},\;45^{\circ},\;30^{\circ}$. And the diameter of the heat pipe was 12.7 mm, 48 axial channels of the same dimensions were attached to the outer wall of the receiver with even spacing in the circumferential direction. The channels are changed to high-temperature sodium heat pipes. Commercial softwares were employed to deal with the radiative heat transfer inside the receiver cavity and the convection heat transfer along the channels. The numerical results are compared and analyzed from the view point of high-temperature solar receiver.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.1175-1178
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• 2005

Brittle materials, especially single-crystal silicon wafer, are widely used for sensors, IC industry, and MEMS applications. e general machining process of crack easy materials is by chemical agents, but it is hazardous and time consuming. Also, it is difficult to get high aspect ratio micro structure. As an alternative tool, an AJM(Abrasive jet machining) is promising method in terms of high aspect ratio and production cost. In this study, to get more precise detail compared to general AJM, photo polymer mask, SU-8, used in photolithography was applied in AJM. Process parameters such as abrasive diameter, air pressure, nozzle diameter, flow rate of abrasive in AJM and a variety of conditions in spin coating were decided. Finally, micro channel and mixer was fabricated to see the efficiency of the AJM with photo polymer mask.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.8
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• pp.188-195
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• 2004

In this paper we analyzed the mechanical behavior with respect to the thickness variation of elastic foundation(fatty tissue) in end-to-end anastomosis. This study considered the preliminary deformed shape induced by suturing in the anastomosis of coronary artery and PTFE with different diameters using simplified suturing model and the fatty tissue surrounding heart and coronary artery for more accurate result using finite element method. Area compliance(CA) was used to analyze the final deformed shape of the anastomotic part with respect to the thickness variation of fatty tissue under mean blood pressure, 100mmHg(13.3㎪). And Equivalent and circumferential stresses in the anastomosis were also analyzed with respect to the change of initial diameter ratio( $R_1$) and fatty tissue thickness( $T_{F}$). The results obtained were as follows : 1 When the elastic foundation, assumed to be incompressive material, surrounded the grafts in anastomosis, the compliance mismatch of artery and PTFE was reduced by 47 -72%. 2. As the initial diameter ratio( $R_1$) became larger, the higher difference of compliance was induced in spite of elastic foundation surrounding grafts. 3. The maximum nondimensional circumferential stress is twice or three times as high as the maximum nondimensional equivalent stress in the anastomotic part.t.

• Journal of ILASS-Korea
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• v.16 no.1
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• pp.44-50
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• 2011

An object of this study is to understand the correlation of injection characteristics and injector dimensions according to biodiesel mixture. The Injection characteristics of different types of common-rail injectors are the number of nozzle holes (5~8), jet cone angle ($146^{\circ}{\sim}153^{\circ}$), hydraulic flow rate (830~900 ml/min) injection quantity and response time. Prior to characteristic experiment, the reference injector has been selected in 6 candidates injectors under the investigation of injected quantity according to the biodiesel mixture so that injector type can be determined. The injector is used for the characteristic experiment which varied the various operating conditions including pressure 23 MPa, 80 MPa, 160 MPa, changing in injection duration 0.16 ms~1.2 ms and even mixture ratio. The result shows that the nozzle hole number and cone angle influence the injection quantity much more than nozzle hole diameter at low injection pressure and the nozzle hole diameter at high injection pressure, post injection duration.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.9
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• pp.1384-1390
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• 2004

The full containment Liquefied Natural Gas(LNG) storage tank is based on a double liquid container concept : two separate containers, one within the other, are capable of containing the LNG. The outer concrete tank provides comer protection(secondary containment) to withstand and safely contain any spill from the inner tank. The comer protection is installed on inside corner surface of outer concrete tank. Because of high and complex stresses, corner protection is designed by ASME section ⅧI Div. 2, Appendix 4 on behalf of API 620 which is main design code for LNG tank. Design guidelines to determine design factors such as liner thickness and knuckle radius are not well understood because Appendix 4 is the design method not based on equation but FEM. Recently, the volume of LNG tank shows a tendency to increase. So it is necessary to set up the design guidelines to cope with change of LNG tank capacity and height/diameter ratio. In this paper, optimum design of corner protection was performed and the design guidelines were suggested by the results of FEM for LNG tanks which have different capacities and height/diameter ratio.