• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.10
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• pp.2359-2368
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• 2013

In this paper, an IRD (internal read data) circuit preventing the reentry into the read mode while keeping the read-out DOUT datum at power-up even if noise such as glitches occurs at signal ports such as an input signal port RD (read) when a power IC is on, is proposed. Also, a pulsed WL (word line) driving method is used to prevent a DC current of several tens of micro amperes from flowing into the read transistor of a differential paired eFuse OTP cell. Thus, reliability is secured by preventing non-blown eFuse links from being blown by the EM (electro-migration). Furthermore, a compared output between a programmed datum and a read-out datum is outputted to the PFb (pass fail bar) pin while performing a sensing margin test with a variable pull-up load in consideration of resistance variation of a programmed eFuse in the program-verify-read mode. The layout size of the 8-bit eFuse OTP IP with a $0.18{\mu}m$ process is $189.625{\mu}m{\times}138.850{\mu}m(=0.0263mm^2)$.

• Journal of the Korean Geotechnical Society
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• v.30 no.2
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• pp.5-18
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• 2014

Depending on the underground load support mechanism, anchors are classified as friction anchors, bearing plate anchors and the recently developed combined friction-bearing plate anchors which combine the characteristics of both the friction and bearing plate type anchors. Even though numerous studies have been performed on bearing plate anchors, there were only few studies performed to observe the failure surface of bearing plate anchors. Furthermore most of the soil materials used on these tests were not real sand but carbon rods. In this study, sand was placed in the soil tank and laboratory tests were performed with bearing plate anchors installed with an embedment depth (H/h) ranging from 1~6. The variation in the pullout capacity and the behaviour of soil with the embedment depth (H/h) were observed. Ground deformation analysis program was also used to analyze soil displacement, zero extension direction, maximum shear strain contours. It was determined from the analysis of the results that at ultimate pullout resistance the deformation was 5 mm and the failure surface occurred in a narrower area when compared with results of the previous researches. It was also observed that the width of the fracture surface gradually becomes wider and expands up to the surface as the deformation increases from 10 mm to 15 mm.

• The Korean Journal of Ecology
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• v.4 no.3_4
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• pp.59-67
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• 1981

Stomatal resistances of the leaves in Heteromeres arbutifolia and of the stems in Ferocactus acanthodes were studied to estimate active and passive behaviors of the guard cells on a theoretical basis. Active and passive stomatal responses to light and water deficit were observed. When the change rate of existent water due to variation of osmotic potential in the guard cells and the loss rate of transpirational water from the guard cells are $\Delta$wi-$\Delta$wt and leaded to active behaviors for opening and closing stomata. However, when stems of F. acanthodes with stomata closecd under the solar irradiation were covered with black cloth and then taken off, behaviors of the guard cells occurred in the condition of $\Delta$wi<$\Delta$wt and were passive. Under the conditiion of $\Delta$wi<$\Delta$wt due to cutout from stems, passive behaviors of the guard cells in H. arbutifolia and F. acanthodes always occurred in spite of the solar irradiation and darkness, respectively. The transpirational resistance coefficients of the guard cells in stems of F. acanthodes (0.380) and Opuntia bigelovii (0.135) wer emuch higher than in leaves of H. arbutifolia (0.034). Moreover, stomatal opening in stems of F. acanthodes during the daytime could be induced by watering. Those results are interpreted as that since the guard cells in desert Crassulacean acid metabolism (CAM) plants always exist in the state of stomatal opening, nocturnal stomatal opening and daytime stomatal closing are exhibited by passive behaviors of the guard cells in the alternant conditioins of $\Delta$wi>$\Delta$wt and $\Delta$wi<$\Delta$wt, respectively.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.519-525
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• 2010

Data from beam-based bond tests for FRP bars in the literature were collected and regression analyses were conducted for the data of splitting failure. Average bond strengths obtained from splice tests were found to be lower and more affected by C/$d_b$ values than average bond strengths from anchorage tests, indicating needs of new design equation for the splice length of FRP bars based on the data of splice tests only. In addition, the variation of bond strengths was greater than that of tensile strengths of FRP bars and, therefore, a new safety factor should be involved for the design equation. Five percent fractile coefficients were used to develop the design equations based on the assumption that load and resistance factors for FRP reinforced concrete structures are same to the factors for steel reinforced concrete structures. The proposed design equations give economical and reliable lengths for development and splice of FRP bars. The proposed equation for splice provides shorter lengths than the ACI 440 equation in case of C/$d_b$ of 3.0 or greater. Because FRP bars are expected to be used in slabs and walls exposed to weather with thick cover and large spacing between bars, the proposed equation gives optimal splice lengths.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.4
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• pp.336-342
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• 1993

To obtain the basic information necessary for the development of soybean varieties well adaptable to upland-paddy field rotational croppings, the difference of growth characteristics between upland and paddy-field including yield potentials of current recommending soybean varieties were evaluated. The growth characteristics, both above and under-ground, which were measured at flowering stage were generally greater in paddy-field but the number of root nodules was much greater in upland, thus the artificial inoculation was practically recommended for soybean growing in paddy-fields. Mean seed yield was generally higher in paddy-fields than in upland. All soybean varieties showed higher seed yield in the early planting date, April 20, were somewhat susceptible to soybean mosaic virus(SMV), thus they could be escaped from the disasterous endemic necrotic soybean mosaic virus(SMV-N). Soybean varieties showed over 4.0 tons/ha seed yield in the paddy-field were Williams 79, Union, SS77053, and Namhaekong. At the same time, Jangyeobkong and Danyeobkong were the most stable soybean varieties among the tested soybean varieties with less than 10% of coefficient variation values in all planting dates in paddy fields. Compared with Hwangkeumkong which is most widely being cultivated on farmer's fields, soybean varieties showed high yields in paddy-field were higher in plant height, less in the number of branches, and more in the number of nodes on main stem. At the same time, they had medium seed size which would bring the good germination and stands. Disease resistance especially for necrotic soybean mosaic virus was also one of the most decisive factors in seed yields for the early planted soybeans.

• Korean Journal of Ecology and Environment
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• v.52 no.4
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• pp.333-339
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• 2019

The Red swamp crawfish Procambarus clarkii is native to the southern United States and inhibits all over the world including the United States, Asia, Africa and Europe. In Europe, it is known to disrupt ecosystems such as competition with native crayfish. In this study, habitats of red swamp crawfish were identified in Jiseok stream (15.5 km section) and Daecho stream (6.1 km section) of Youngsan river. A total 33 red swamp crawfish were captured. A female captured in Jiseok stream carried 215 newly hatched red swamp crawfish in her the burrow. As a result of the analysis of the habitat environment, the water temperature was ranged of 2.4~32.8℃, conductivity was 53.4~502.3 μS cm^-1 and DO was 0.74~22.64 mg L^-1. As a result of measuring HOBO, the temperature ranged from -9~48.1℃, showing a change of 57.1℃ throughout the year. The variation of the water temperature throughout the year from 2.9~33.9℃ was found to be 31℃. Red swamp crawfish have a high adaptability and a wide range of environmental resistance, and report a sharp increase in newly invaded areas, negatively affecting indigenous organisms. In addition, it can be used as a medium for the spread of diseases and parasites, so prompt investigation and research should be carried out.

• Journal of the Korean Vacuum Society
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• v.22 no.3
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• pp.168-173
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• 2013

In this paper, we would like to introduce Electron Relay Enhancer (ERE), a supplementary device, which improves commercial solar cell efficiency minimizing electron-hole recombination of solar cell. The ERE in this study is mainly composed of two capacitors which are connected to AC power source and bridge diode system which controls electron flow direction. Two capacitors repeat collecting electrons from solar cell and pumping the collected electrons to load resistance or inverter through the bridge diode system. While one positively charged capacitor collect electrons, the other negatively charged one pumps electrons. A positively charged capacitor pulls the more exited electrons from the solar cell, before the exited electrons recombine the holes in solar cell. That is why the ERE system enhances solar cell efficiency. As a result, the measured power increase of the solar cell with the ERE is varied from 5.9 W to 25.6 W in each experimental condition. Maximal increase rate of the solar cell power with ERE is 30.8% of solar cell power without ERE.

• Korean Journal of Materials Research
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• v.20 no.4
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• pp.210-216
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• 2010

This paper investigates the dependence of a-Si:H/c-Si passivation and heterojunction solar cell performances on various cleaning processes of silicon wafers. It is observed that the passivation quality of a-Si:H thin-films on c-Si wafers depends highly on the initial H-termination properties of the wafer surface. The effective minority carrier lifetime (MCLT) of highly H-terminated wafer is beneficial for obtaining high quality passivation of a-Si:H/c-Si. The wafers passivated by p(n)-doped a-Si:H layers have low MCLT regardless of the initial H-termination quality. On the other hand, the MCLT of wafers incorporating intrinsic (i) a-Si:H as a passivation layer shows sensitive variation with initial cleaning and H-termination schemes. By applying the improved cleaning processes, we can obtain an MCLT of $100{\mu}sec$ after H-termination and above $600{\mu}sec$ after i a-Si:H thin film deposition. By adapting improved cleaning processes and by improving passivation and doped layers, we can fabricate a-Si:H/c-Si heterojunction solar cells with an active area conversion efficiency of 18.42%, which cells have an open circuit voltage of 0.670V, short circuit current of $37.31\;mA/cm^2$ and fill factor of 0.7374. These cells show more than 20% pseudo efficiency measured by Suns-$V_{oc}$ with an elimination of series resistance.

• Journal of Chest Surgery
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• v.30 no.5
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• pp.486-492
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• 1997

We r viewed a policy of primary surgical closure of large ventricular septal defects in small infants. Sixty-three infants met criteria for inclusion in the study, and were divided into two groups based on age: group 1 infants aged less than 5 months(n = 31), and group 2 infants aged 5 months or more(n = 32). Both groups had similar variation in ventricular septal defect location(paramembranous versus muscular), and showed no significant difference in left to right shunt and in ratio of systemic and pulmonary vascualr resistance. Three early deaths(9.7%) occurred in group 1, but no death(0%) in group 2. The causes of death were preoperative cardiac arrest and cerebral injury followed by postoperative respiratory insufficiency in two patients, and preoperative tracheomalacia followed by laryngeal edema and respiratory arrest in one Two patients in group 1 showed postoperative low cardiac output syndrome(6.5% in group 1 versus 0% in group 2). There was no late death during the follow-up per od in both groups. No surviving patients had postoperative patch leakage, or required a second operation. These results indicate that primary surgical closure of large ventricular septal defects, if logical perioperative care is accompanied, can be saefly performed in small infants aged less than 5 months with low postoperative mortality or morbidity rates.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2002.05a
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• pp.23-28
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• 2002

This paper describes the machining characteristics of the $MoSi_2$ based composites by electric discharge drilling with various tubular electrodes, besides, Hardness characteristics and microstructures of $Nb/MoSi_2$ laminate composites were evaluated from the variation of fabricating conditions such as preparation temperature, applied pressure and pressure holding time. $MoSi_2$ -based composites has been developed in new materials for jet engine of supersonic-speed airplanes and gas turbine for high- temperature generator. Achieving this objective may require new hard materials with high strength and high temperature-resistance. However, With the exception of grinding, traditional machining methods are not applicable to these new materials. Electric discharge machining (EDM) is a thermal process that utilizes a spark discharge to melt a conductive material, the tool electrode being almost non-unloaded, because there is no direct contact between the tool electrode and the workpiece. By combining a nonconducting ceramics with more conducting ceramic it was possible to raise the electrical conductivity. From experimental results, it was found that the lamination from Nb sheet and $MoSi_2$ powder was an excellent strategy to improve hardness characteristics of monolithic $MoSi_2$. However, interfacial reaction products like (Nb, Mo)$SiO_2$ and $Nb_2Si_3$ formed at the interface of $Nb/MoSi_2$ and increased with fabricating temperature. $MoSi_2$ composites which a hole drilling was not possible by the conventional machining process, enhanced the capacity of ED-drilling by adding $NbSi_2$ relative to that of SiC or $ZrO_2$ reinforcements.