• Journal of Korean Society of Forest Science
• /
• v.75 no.1
• /
• pp.51-54
• /
• 1986

The good growth of Populus alba ${\times}$ P. glandulosa is shown at the foothill of the mountain where good soil moisture is available, but its growth is poor at the upper part of the mountain where soil moisture is limitted. Stomatal frequency, stomatal size and transpiration rates that affect soil moisture demand were determined in order to know how this character is inherited from its parents. Number of stomata per $mm^2$, length and width of stomata from the abaxial leaf and transpiration rate ($g/cm^2$) per day in P. alba ${\times}$ P. glandulosa showed intermediate values between those of their parents, while P. alba showed the highest values and P. davidiana the lowest values. The values of stomatal frequency of P. alba ${\times}$ P. glandulosa were close to the expected mean values of parents in the $x^2$ test, and in the regression analysis the transpiration rates for the hybrid and its midparent had strong relationship with 0.97 of regression coefficient. The fact that these intermediate characteristics were observed in the hybrid suggests incomplete dominance in the hybrid. It is concluded that soil moisture demand in P. alba ${\times}$ P. glandulosa and its parents is closed related to stomatal frequency, stomatal size and transpiration rate.

• Journal of the Korean Wood Science and Technology
• /
• v.44 no.1
• /
• pp.57-66
• /
• 2016

In order to develop materials with a low environmental load for restoring the destroyed forest, seven types of wood-concrete hybrid laminated materials were manufactured with four softwoods, three hardwoods and concrete, and the effect of wood density on bending creep property was investigated. The bending creep curves showed a shape to considerably increase at the upper right side, and the curves were found to show a linear behavior beyond about 30 min - 1 hour, as behaviors of solid woods and wood-based materials. The initial compliances of wood-concrete hybrid-laminated materials decreased with an increase in the wood density, and those values showed 0.9 - 1.2 times of the concrete one. The creep compliances of hybrid laminated materials showed very low values, which were 0.4 - 0.8 times of the concrete ones. The relative creep were very low with a range from 8.2% to 17.0% range, which were 0.3 - 0.7 times of the concrete ones. These results indicate that these materials can be applied for restoring the destroyed forest to reduce creep deformation of the conventional concrete materials by hybrid-laminating concrete and woods.

• Korean Journal of Soil Science and Fertilizer
• /
• v.37 no.3
• /
• pp.136-142
• /
• 2004

Though diverse methods have been developed to characterize surface charge of soils and pure minerals, there is not still a reliable and rapid method for differentiating permanent charge from variable charge. Thus, it is needed to find out a reasonable method for measuring permanent and pH-dependent charge of soils. In this study various methods such as Cs-adsorption method, Hybrid model, $NH_4{^+}$-adsorption method and theoretical calculation of lattice charge were applied to measure permanent charge of montmorillonite and illite. Calculated lattice charge was $71.82cmol\;kg^{-1}$ and $14.20cmol\;kg^{-1}$ for montmorillonite and illite, respectively. The permanent charge measured by Cs-adsorption method were $78.23cmol\;kg^{-1}$ and $11.13cmol\;kg^{-1}$ for montmorillonite and illite, respectively. The differences between the values measured by Cs-adsorption method and the calculated lattice charge were not different significantly as $6.41cmol\;kg^{-1}$ and $3.07cmol\;kg^{-1}$. But, Hybrid model showed an underestimated values when applied to clay minerals with predominant amounts of permanent charge. The experimental results showed Cs-adsorption method was more reasonable for permanent charge measurement than the Hybrid model for illlte or montmorillonitetype clays.

• Journal of Adhesion and Interface
• /
• v.10 no.2
• /
• pp.98-105
• /
• 2009

Poly(amic acid) was synthesized from the reaction of p-PDA/ODA and PMDA/BPDA and silane oligomer containing epoxy group was also synthesized from the reaction of tetramethylorthosilicate (TMOS) and glycidol. After hybridizing poly (amic acid) and silane oligomer, they were effectively converted into polyimide/silica hybrid films by thermal imidization process. As the silica contents in hybrid films increased, CTE values decreased from 17 ppm/K to 10 ppm/K and the tensile modulus increased, in spite of decreasing tensile strength. In addition, the peel test showed that the adhesion strength of hybrid film was enhanced from $0.43kg_f/cm$ to $1.02kg_f/cm$. Therefore, it could be concluded that the polyimide/silica hybrid film is effective to enhance adhesion strength for FCCL films.

• Korean Journal of Materials Research
• /
• v.22 no.2
• /
• pp.97-102
• /
• 2012

The microstructure and tensile properties of Al-Mn/Al-Si hybrid aluminum alloys prepared by electromagnetic duocasting were investigated. Only the Al-Mn alloy showed the typical cast microstructure of columnar and equiaxed crystals. The primary dendrites and eutectic structure were clearly observed in the Al-Si alloy. There existed a macro-interface of Al-Mn/Al-Si alloys in the hybrid aluminum alloys. The macro-interface was well bonded, and the growth of primary dendrites in Al-Si alloy occurred from the macro-interface. The Al-Mn/Al-Si hybrid aluminum alloys with a well-bonded macro-interface showed excellent tensile strength and 0.2% proof stress, both of which are comparable to those values for binary Al-Mn alloy, indicating that the strength is preferentially dominated by the deformation of the Al-Mn alloy side. However, the degree of elongation was between that of binary Al-Mn and Al-Si alloys. The Al-Mn/Al-Si hybrid aluminum alloys were fractured on the Al-Mn alloy side. This was considered to have resulted from the limited deformation in the Al-Mn alloy side, which led to relatively low elongation compared to the binary Al-Mn alloy.

• Journal of Intelligence and Information Systems
• /
• v.10 no.2
• /
• pp.39-51
• /
• 2004

Product factory is a real-time financial product design system for the Internet customers. The hybrid product is a product taking combined characteristics of two different products. Hybrid product factory is a product factory that designs hybrid products from two different products based on both business rules and customer requirements. Though the importance of product factory is emphasized in the industry, there has not been much research peformed regarding product factory. In this research, we developed a product factory system that designs hybrid products. To design a hybrid product, it is necessary to have a method to combine attributes and values of two different products, and a method to control the combining operations to properly reflect business requirements. In this research, we developed low different combining operators and business rule representations. rn addition, to prove the effectiveness of this methods, we implemented a prototypical system and demonstrated on cases regarding financial loan products.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.34 no.3
• /
• pp.269-274
• /
• 2010

As a preliminary study on a SOFC-GT hybrid system integrated a with coal-gasification system, the influence of the concentrations of $H_2$ and CO in syngas on the performance characteristics of the hybrid system is investigated. It is expected that the differences in the heating values of fuels with different compositions trigger the off-design operation of the gas turbine and result in different performance characteristics of the overall hybrid system. Syngas compositions are found to affect the SOFC performance. Performance of hybrid system with carbon monoxide is poorer than the case with hydrogen. In the case of part-load performance with syngas, performance degradation at part-load operating conditions with hydrogen is more dominant than the case with carbon monoxide.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.15 no.6
• /
• pp.100-109
• /
• 2011

Recently, the concrete-steel hybrid extradosed bridge has been proposed as alternative bridge type at long span site. The hybrid extradosed bridge adopts light orthogonal deck girder instead of heavy concrete deck girder at the center span of bridge, and it enables to construct long-span bridge. And also, for this bridge type the decrease of self-weight of girder enables to reduce girder depth and side span length of extradosed bridge, so its type has more efficient structural behavior and makes it possible to perform optimal bridge design. Therefore, it is very important to set up the procedure and parameters of optimal design for concrete-steel hybrid extradosed bridge. In this study, the effects of design parameters (the variation of pylon height, bridge deck depth and orthogonal deck girder length) are discussed. And numerical analysis and sensitivity analysis are carried out according to these parameters. And design weight values about these parameters are quantitatively suggested to reflect characteristics of concrete-steel hybrid bridge.

• Journal of Korea Foundry Society
• /
• v.17 no.4
• /
• pp.338-346
• /
• 1997

Mechanical properties of ($10%Al_2O_3{\cdot}SiO_2+5%Ni$)/Al hybrid composites fabricated by the reaction squeeze casting were compared with those of ($15%Al_2O_3{\cdot}SiO_2$)/Ai composites. Al-Ni intermetallic compounds ($10{\sim}20 {\mu}m$) formed by the reaction between nickel powder and molten aluminum were uniformly distributed in the Al matrix. These intermetallic compounds were identified as $Al_3Ni$ using X-ray diffraction analysis and they resulted in beneficial effects on room and high temperature strength and wear resistance. Microhardness values of ($10%Al_2O_3{\cdot}SiO_2+5%Ni$)/Al hybrid composite were greater by about 100Hv than those of ($15%Al_2O_3{\cdot}SiO_2$)/Al composite. Wear resistance of ($10%Al_2O_3{\cdot}SiO_2+5%Ni$)/Al hybrid composites was superior to that of ($15%Al_2O_3{\cdot}SiO_2$)/Al composites regardless of the applied load. While tensile and yield strength of ($10%Al_2O_3{\cdot}SiO_2+5%Ni$)/Al hybrid composites were greater at room temperature and $300^{\circ}C$, strength drop at high temperature was much smaller in hybrid composites.

• Korean Journal of Radiology
• /
• v.23 no.11
• /
• pp.1044-1054
• /
• 2022

Objective: This study aimed to investigate whether a deep learning reconstruction (DLR) method improves the image quality, stent evaluation, and visibility of the valve apparatus in coronary computed tomography angiography (CCTA) when compared with filtered back projection (FBP) and hybrid iterative reconstruction (IR) methods. Materials and Methods: CCTA images of 51 patients (mean age ± standard deviation [SD], 63.9 ± 9.8 years, 36 male) who underwent examination at a single institution were reconstructed using DLR, FBP, and hybrid IR methods and reviewed. CT attenuation, image noise, signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and stent evaluation, including 10%-90% edge rise slope (ERS) and 10%-90% edge rise distance (ERD), were measured. Quantitative data are summarized as the mean ± SD. The subjective visual scores (1 for worst -5 for best) of the images were obtained for the following: overall image quality, image noise, and appearance of stent, vessel, and aortic and tricuspid valve apparatus (annulus, leaflets, papillary muscles, and chordae tendineae). These parameters were compared between the DLR, FBP, and hybrid IR methods. Results: DLR provided higher Hounsfield unit (HU) values in the aorta and similar attenuation in the fat and muscle compared with FBP and hybrid IR. The image noise in HU was significantly lower in DLR (12.6 ± 2.2) than in hybrid IR (24.2 ± 3.0) and FBP (54.2 ± 9.5) (p < 0.001). The SNR and CNR were significantly higher in the DLR group than in the FBP and hybrid IR groups (p < 0.001). In the coronary stent, the mean value of ERS was significantly higher in DLR (1260.4 ± 242.5 HU/mm) than that of FBP (801.9 ± 170.7 HU/mm) and hybrid IR (641.9 ± 112.0 HU/mm). The mean value of ERD was measured as 0.8 ± 0.1 mm for DLR while it was 1.1 ± 0.2 mm for FBP and 1.1 ± 0.2 mm for hybrid IR. The subjective visual scores were higher in the DLR than in the images reconstructed with FBP and hybrid IR. Conclusion: DLR reconstruction provided better images than FBP and hybrid IR reconstruction.