• Geomechanics and Engineering
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• v.31 no.3
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• pp.249-263
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• 2022

The specially-shaped Polycrystalline Diamond Compact (PDC) cutter is widely used in drill bit design due to its advantages of high rock cutting efficiency, strong impact resistance and long service life in hard and abrasive formation drilling. A detailed understanding of rock cutting behavior of worn specially-shaped PDC cutter is essential to improve the drilling efficiency and decrease the drilling costs. In this paper, the theoretical models of two new principles (loading performance (LP) and cutting performance (CP)) are derived for evaluating the cutting process of worn specially-shaped cutter, the theoretical models consider the factors, such as cutter geometry, aggressiveness, stress state, working life, and rock cutting efficiency. Besides, the numerical model of heterogeneous granite is developed using finite element method combined with Voronoi tessellation, the LP and CP of 12 kinds of worn specially-shaped PDC (SPDC) cutters are analyzed. The results found that the mechanical specific energy (MSE) of worn cutters first increase and then decrease with increasing the cutting depth, and the MSE increase with the increase of back rake angle except for Conical cutter and Wedge-shaped cutter. From the perspective of CP, the worn PDC cutters are more suitable for the smaller cutting depths, and the back rake angle has little effect on the CP of the specially-shaped worn PDC cutters. Conical cutter, Saddle-shaped cutter and Ellipse-shaped cutter have the highest CP value, while Rhombus-shaped cutter, Convex cutter and Wedge-shaped cutter have the lowest value in selecting cutters. This research leads to an enhanced understanding of rock-breaking mechanisms of worn SPDC cutters, and provides the basis to select of specially-shaped PDC cutters for the specific target formation.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.8-9
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• 2017

Soybean yield has been low and unstable in Japan and other areas in East Asia, despite long history of cultivation. This is contrasting with consistent increase of yield in North and South America. This presentation tries to describe perspective of breaking stagnation of soybean yield in East Asia, considering the factors of the different yields between regions. Large amount of rainfall with occasional dry-spell in the summer is a nature of monsoon climate and as frequently stated excess water is the factor of low and unstable soybean yield. For example, there exists a great deal of field-to-field variation in yield of 'Tanbaguro' soybean, which is reputed for high market value and thus cultivated intensively and this results in low average yield. According to our field survey, a major portion of yield variation occurs in early growth period. Soybean production on drained paddy fields is also vulnerable to drought stress after flowering. An analysis at the above study site demonstrated a substantial field-to-field variation of canopy transpiration activity in the mid-summer, but the variation of pod-set was not as large as that of early growth. As frequently mentioned by the contest winners of good practice farming, avoidance of excess water problem in the early growth period is of greatest importance. A series of technological development took place in Japan in crop management for stable crop establishment and growth, that includes seed-bed preparation with ridge and/or chisel ploughing, adjustment of seed moisture content, seed treatment with mancozeb+metalaxyl and the water table control system, FOEAS. A unique success is seen in the tidal swamp area in South Sumatra with the Saturated Soil Culture (SSC), which is for managing acidity problem of pyrite soils. In 2016, an average yield of $2.4tha^{-1}$ was recorded for a 450 ha area with SSC (Ghulamahdi 2017, personal communication). This is a sort of raised bed culture and thus the moisture condition is kept markedly stable during growth period. For genetic control, too, many attempts are on-going for better emergence and plant growth after emergence under excess water. There seems to exist two aspects of excess water resistance, one related to phytophthora resistance and the other with better growth under excess water. The improvement for the latter is particularly challenging and genomic approach is expected to be effectively utilized. The crop model simulation would estimate/evaluate the impact of environmental and genetic factors. But comprehensive crop models for soybean are mainly for cultivations on upland fields and crop response to excess water is not fully accounted for. A soybean model for production on drained paddy fields under monsoon climate is demanded to coordinate technological development under changing climate. We recently recognized that the yield potential of recent US cultivars is greater than that of Japanese cultivars and this also may be responsible for different yield trends. Cultivar comparisons proved that higher yields are associated with greater biomass production specifically during early seed filling, in which high and well sustained activity of leaf gas exchange is related. In fact, the leaf stomatal conductance is considered to have been improved during last a couple of decades in the USA through selections for high yield in several crop species. It is suspected that priority to product quality of soybean as food crop, especially large seed size in Japan, did not allow efficient improvement of productivity. We also recently found a substantial variation of yielding performance under an environment of Indonesia among divergent cultivars from tropical and temperate regions through in a part biomass productivity. Gas exchange activity again seems to be involved. Unlike in North America where transpiration adjustment is considered necessary to avoid terminal drought, under the monsoon climate with wet summer plants with higher activity of gas exchange than current level might be advantageous. In order to explore higher or better-adjusted canopy function, the methodological development is demanded for canopy-level evaluation of transpiration activity. The stagnation of soybean yield would be broken through controlling variable water environment and breeding efforts to improve the quality-oriented cultivars for stable and high yield.

• Proceedings of the Korean Society of Crop Science Conference
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• 2017.06a
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• pp.95-95
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• 2017

Lodging is a serious issue in rice production, because it drastically decreases the biomass production and grain yield. Since the Green Revolution, the lodging resistance has been increased by lowering the moment of above-ground parts due to the short culm by the semi-dwarf gene sd1. However, it has been pointed out that sd1 alone has suppressive effects for biomass production and yield. To increase rice yield, the long-culm and large panicle type varieties with a superior lodging resistance need to be developed. To improve the lodging resistance and yield of these type varieties, it would be effective to identify novel alleles for these traits underlying natural variations in rice and to pyramid these alleles to a single rice variety. In order to perform this strategy, we have developed new rice lines derived from crosses among varieties with superior alleles. At first, TULT-gh-5-5 was selected from a cross between strong culm and high biomass variety Leaf Star and high-yielding variety Takanari, and TUAT-32HB was selected from a cross between high-yielding variety Akenohoshi and Takanari. Then, we developed the super thick-culm and super grain-bearing line, LTAT-29 derived from a cross between TULT-gh-5-5 and TUAT-32HB. In the current study, to identify the QTLs and genes relating to the strong culm and the high yield of LTAT-29, we performed QTL analysis using SNPs markers with $F_2$ population derived from a cross between LTAT-29 and Takanari. LTAT-29 has never lodged throughout the growth period despite it had long culms and heavy panicles. LTAT-29 had a larger outer diameter of the culm and twice the size of the section modulus than Takanari. As a result, the bending moment at breaking of LTAT-29 was significantly larger than that of Takanari. Brown rice yield of LTAT-29 was $9.2t\;ha^{-1}$ about 10% higher than that of Takanari due to the larger number of spikelets per panicle. LTAT-29 had a greater number of secondary branches per panicle. In the $F_2$ population between LTAT-29 and Takanari, we found continuous frequency distributions in the section modulus and the spikelet number per panicle. Two QTLs increased the section modulus by the alleles of LTAT-29 were detected on Chr.1L and Chr.2L. One QTL increased the spikelet number per panicle of Takanari by the allele of LTAT-29 was detected on Chr.1L, and two QTLs increased the number of secondary branches per panicle by the alleles of LTAT-29 were detected on Chr.1L and Chr.4L. It was found that the alleles of these QTLs were the japonica type originated from Leaf Star or Akenohoshi. The novel QTLs for the traits related to super thick-culm and super grain-bearing and their combinations could be utilized for improving the lodging resistance and yield in rice varieties.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.49 no.6
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• pp.441-446
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• 2004

To reduce water input by water-saving irrigation techniques a field study was carried out with three water managements, very shallow intermittent irrigation (VSII, 2cm), shallow intermittent irrigation (SII, 4cm) and traditional deep water irrigation (DWI, 10cm) for two years. Rice growth and grain yields of three water managements were not significantly different. However, when the water irrigation depth was decreased, the breaking and lodging resistance were increased and the roots were widely distributed into deeper paddy soil. More numbers of both annual and perennial weeds were occurred in VSII than in DWI at maximum heading stage and only the number of perennial weeds was three times in VSII than in DWI at heading stage. The total water inputs were 777, 654 and 527 mm in DWI, SII and VSII, therefore the water-saving rates of VSII and SII were $32.2\%\;and\;15.9\%$ compared to typical deep water irrigation. The water-productivity (Rice yield to water input) was highest in VSII as 0.94 and followed by SII as 0.76 and DWI as 0.63. In the face of water scarcity, it is very important to find or develope water saving irrigation system and find ways to increase the productivity of water used for rice cultivation.

• Fire Science and Engineering
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• v.13 no.4
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• pp.38-55
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• 1999

In order practically to use fire-defective glazing materials for the compartment wall where a fire-protection rating is mandated, there have been many trials internationally, This research focuses on a feasibility that, if certain water film covered all surface of glass, the glazing system can endure without breaking out under the compartment fire. First of all, a water film spray system was specially designed to wet the entire surface of the glass and also to have tiny small amount of water rebounded from the surface after emitted from nozzles. After this system has proven to have perfect performance, small-scale tests were done to find out if the water film covered glazing system react to the high temperature curve in a small furnace room. Finally, on basis of the obtained data, full-scale experiments were done so that water-film covered glazing system can pass the Korean Standard (KS) test for fire resistance, KS F2257.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.38 no.3
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• pp.219-227
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• 1993

Broadcast-seeded rice in submerged paddy frequently lodge in the field. In general, the causes of lodging in rice cultivation differ with different cultural methods. This study was conducted to investigate the causes of lodging in broadcast-seeded rice (BSR) and hand-transplanted rice (HTR) under four nitrogen (N) levels. Lodging in BSR was mainly a root lodging due to shallow root distribution, while that in HTR showed a bending type owing to deep rooting system. At the upper soil layer (0-5cm from the surface of ground) the root distribution of BSR (65.2%) was much larger than that of HTR (51.6%), whereas at the 5-10cm soil layer the root distribution of BSR (18.5%) was much smaller than that of HTR (28.0%). The depth of buried culm base was much shallower in BSR (1.2cm) than in HTR (4.0cm). The plant height, fresh weight, lodging index, culm diameter and thickness in HTR were much greater than those in BSR, and the breaking strength of lower internode was similar in the two cultivation methods indicating that HTR would have more lodging causes than BSR. In spite of . the more advantages to lodging resistance in BSR it severely lodged in the field. The main lodging-inducing factors of BSR were the shallow root distribution and shallow depth of buried culm base. Besides these, the higher ratio of gravity center of culm was an important factor. This result suggested that for the fundamental prevention of lodging in BSR, an ideotype of rice plant with ' a deep-rooted behavior ' should be developed.

• Journal of the Society of Naval Architects of Korea
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• v.41 no.6
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• pp.120-125
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• 2004

There are very few numbers of 115K FPP (Fixed Pitch Propulsion) Tankers for the Baltic ice class IA because the minimum power requirement of FMA (Finish- Swedish Maritime Association) needs quite large engine power and the 40 m Beam is out of calculation range of FMA minimum power requirements. The shipyard has no choice except to increase the engine power to satisfy FMA minimum power requirement Rule. And the operation cost, efficiency of hullform and its building cost are not good from the ship owners' point of view To solve this problem, the experience of ice breaking tanker development and the ice tank test results were adopted. The main idea to reduce the ice resistance is by reducing waterline angle at design load waterline. The reason behind the main idea is to reduce the ice-clearing force. Two hull forms were developed to satisfy Baltic Ice class IA. Two ice tank tests and one towing tank test was performed at MARC (Kvaener-Masa Arctic Research Center) and SSMB (Samsung Ship Model Basin) facilities, respectively. The purpose of these tests was to verify the performance in ice and open water respectively The hull form 2 shows less speed loss compared to Hull form 1 in open water operation but hull form 2 shows very good ice clearing ability. finally the Hull Form 2 satisfying Baltic ice class IA. The merit of this hull form is to use the same engine capacity and no major design changes in hull form and other related designs But the hull structure has to be changed according to the ice class grade. The difference in two hull form development methods, ice model test methods and analysis methods of ice model test will be described in this paper.

• Journal of Haehwa Medicine
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• v.9 no.1
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• pp.201-214
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• 2000

Precise and detailed clinical research and evaluation based on objective standards are imperative factors in securing reliability of a clinical test. Built on this principle, this clinical test has been conducted during the period between March 1999 and March 2000 dealing with 31 outpatients treated with ShiHo-GuizhiTang or ShiHo-GuizhiTang modify and ShiHo-GuizhiTang mixed prescriptions at the Sung-bo ORIENTAL MEDICAL CLINIC. A variety of information relating to those patients has been collected and analyzed under such criteria as precise diagnoses and their clinical effectiveness. The analysis was duly based on "The theory of cold syndrome". Then, the 31 patients' individual clinical information was compared one another by breaking down the results into sub-categories including gender, age, disease, main symptom, blood pressure, pulse beats, syndrome of abdomen, treatment period, modify and mixed prescription, and evaluation. The result of this clinical test can be summarized as follows: First, ShiHo-GuizhiTang appears to be more frequently prescribed in the case of female patients than in the case of male patients despite the fact that it does not necessarily need to be applied only to female. In addition, the numbers of prescriptions of ShiHo-GuizhiTang in the two age groups consisting of elementary school children and economically active adults respectively were the highest among other age groups. Second, ShiHo-GuizhiTang proved to be most effective in treatment for respiratory ailments and arthritis. Third, ShiHo-GuizhiTang brought down blood pressure of hypertension patients and at the same time benefited patients with normal or lower-than-normal blood pressure who were vulnerable to diseases due to low disease-resistance. Fourth, ShiHo-GuizhiTang was effective in the case of frequent pulse(rapid pulse) and thereby indicating the fact it carries Taiyang superficies syndrome. 지맥 arises from suppressed immune responses owing to adrenocortical hormones. ShiHo-GuizhiTang controls and revitalizes those suppressed immune systems which stem from slow pulse and, as a consequence of that process, helps them return to normal condition of pulse. Fifth, from the standpoint of syndrome of abdomen, feeling of obstruction in the epigastrium serves as an important standard in the process of diagnosing diseases and evaluating effectiveness of treatments. Sixth, according to the results of the clinical test with the 31 patients, a total of 81 percent of test subjects benefited from the treatment. The figure is the sum of 52 percent of I-class (both main symptom and accompanying symptoms had been eliminated) and 29 percent of II-class (part of main symptom and accompanying symptoms had been eliminated) respectively. All told it is safe to say that ShiHo-GuizhiTang can elect to be a viable clinical treatment. In conclusion, it is estimated that this clinical study has drawn up guidelines for objective diagnostic standards and evaluation on specific treatments' effectiveness. This will lead to more general application of ShiHo-GuizhiTang. On top of that, this study could also provide an opportunity to stress the significance of ShiHo-GuizhiTang and ShiHo-GuizhiTang modify and ShiHo-GuizhiTang mixed prescriptions as an alternative treatment for collagen disease which comes from environmental degradation and pollution.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.6
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• pp.833-839
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• 2005

This study was conducted to demonstrate whether dietary Ca and the soy isoflavones supplementation could reduce the bone loss associated with estrogen deficiency. Nine week-old female rats (SD) were ovariectomized and then fed on diet of low $(0.1\%)$ or normal $(0.5\%)$ Ca supplemented with soy isoflavones (80 and 160 ppm) for 6 weeks. The ovariectomized and sham-operated rats showed normal serum Ca and P levels, and dietary Ca and soy isoflavones did not changed them. The serum alkaline phosphatase activity was increased in all ovariectomized rats, especially in the rats fed low Ca diet regardless of isoflavone supplementation. The serum tartrate-resistance acid phosphatase was not significantly different among the ovariectomized rats and were not changed by dietary Ca and isoflavones. Breaking force of femur was higher in the rats fed the nomral Ca diets and not statistically changed by soy isoflavone supplementation. Femoral and lumbar Ca and P contents decreased in the ovariectomized rats and the soy isoflavones-80 ppm supplementation significantly enhanced bone minerals, but the soy isoflavones-160 ppm supplementation did not. Dietary Ca increased lumbar Ca and P contents. The results of this study have suggested that the soy isoflavones 80 ppm supplementation could be sufficient to prevent bone loss in ovariectomized rats and normal Ca supplementation could enhance the effect of soy isoflavones on bone protection.

• Horticultural Science & Technology
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• v.31 no.5
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• pp.648-651
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• 2013

A new cultivar 'Daewang' strawberry was developed by the National Institute of Horticultural & Herbal Science for forcing culture in 2010. The cultivar 'Daewang' was originated from the cross between 'Maehyang', a high firmness cultivar and 'Wongyo 3111', a high sugar content in 2006. The cultivar shows erect plant type, vigorous growth habit, early flower bud differentiation with 12-15 flowers per cluster from planting on healthy nursery. Fruits of 'Daewang' are conical type having a bright red skin color, and 16-17 g in an average weight. 'Daewang' is suitable for forcing culture as time required for dormancy breaking ranged between 50 and 100 hours. This cultivar has excellent taste for high sugar/acid ratio as sugar content of $11.1^{\circ}Brix$, acidity of 0.39% with abundant texture and can be harvested by late spring because the fruit firmness of 'Daewang' was $18.2g{\cdot}mm^{-2}$ that was about $7.9g{\cdot}mm^{-2}$ higher than $10.3g{\cdot}mm^{-2}$ of 'Akihime' cultivar. But although total yield is not significantly different from 'Akihime' cultivar, its marketable yield is remarkably higher than that of 'Akihime' cultivar. Disease and pest resistance of 'Daewang' have a tendency to sensitive powdery mildew, anthracnose and spotted spider.