• Journal of Mechanical Science and Technology
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• v.17 no.11
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• pp.1638-1649
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• 2003

A study is made on the characterization of damage tolerance by spherical indentation in hardly coated layer structure with modest elastic modulus mismatch. A hard silicon nitride is prepared for the coating material and silicon nitride with 5wt% of boron nitride composites for underlayer. Hot pressing to eliminate the effect of interface delamination during the fracture makes strong interfacial bonding. The elastic modulus mismatch between the layers is not only large enough to suppress the surface crack initiation from the coating layer but sufficiently small to prevent the initiation of radial crack from the interface. The strength degradation of the layer structure after sphere contact indentation does not significantly occur, while the degradation of silicon nitride-boron nitride composite is critical at a high load and high number of contacts.

• Proceedings of the KSME Conference
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• 2001.06a
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• pp.465-470
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• 2001

The adhesively-bonded joints considered in this investigation include single-lap joint and double-lap joint. For an adhesively bonded double-lap joint, end mismatch between the two cuter adherends(upper, lower) can not removed completely although it can be controlled within a manufacturing tolerance. This paper shows that the end mismatch introduces local bending and end mismatch affects the shear and peel stresses in the adhesive. The double-lap joint with an end mismatch is affected of adhesive thickness, material properties of adhesive and adherend etc. Also, we concluded that there are critical value of an end mismatch to provoke the interface fracture.

• Journal of Microbiology and Biotechnology
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• v.31 no.7
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• pp.903-911
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• 2021

Previous studies have modified microbial genomes by introducing gene cassettes containing selectable markers and homologous DNA fragments. However, this requires several steps including homologous recombination and excision of unnecessary DNA regions, such as selectable markers from the modified genome. Further, genomic manipulation often leaves scars and traces that interfere with downstream iterative genome engineering. A decade ago, the CRISPR/Cas system (also known as the bacterial adaptive immune system) revolutionized genome editing technology. Among the various CRISPR nucleases of numerous bacteria and archaea, the Cas9 and Cas12a (Cpf1) systems have been largely adopted for genome editing in all living organisms due to their simplicity, as they consist of a single polypeptide nuclease with a target-recognizing RNA. However, accurate and fine-tuned genome editing remains challenging due to mismatch tolerance and protospacer adjacent motif (PAM)-dependent target recognition. Therefore, this review describes how to overcome the aforementioned hurdles, which especially affect genome editing in higher organisms. Additionally, the biological significance of CRISPR-mediated microbial genome editing is discussed, and future research and development directions are also proposed.

• Journal of Microbiology and Biotechnology
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• v.30 no.10
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• pp.1583-1591
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• 2020

CRISPR/Cpf1 has emerged as a new CRISPR-based genome editing tool because, in comparison with CRIPSR/Cas9, it has a different T-rich PAM sequence to expand the target DNA sequence. Single-base editing in the microbial genome can be facilitated by oligonucleotide-directed mutagenesis (ODM) followed by negative selection with the CRISPR/Cpf1 system. However, single point mutations aided by Cpf1 negative selection have been rarely reported in Corynebacterium glutamicum. This study aimed to introduce an amber stop codon in crtEb encoding lycopene hydratase, through ODM and Cpf1-mediated negative selection; deficiency of this enzyme causes pink coloration due to lycopene accumulation in C. glutamicum. Consequently, on using double-, triple-, and quadruple-base-mutagenic oligonucleotides, 91.5-95.3% pink cells were obtained among the total live C. glutamicum cells. However, among the negatively selected live cells, 0.6% pink cells were obtained using single-base-mutagenic oligonucleotides, indicating that very few single-base mutations were introduced, possibly owing to mismatch tolerance. This led to the consideration of various target-mismatched crRNAs to prevent the death of single-base-edited cells. Consequently, we obtained 99.7% pink colonies after CRISPR/Cpf1-mediated negative selection using an appropriate single-mismatched crRNA. Furthermore, Sanger sequencing revealed that single-base mutations were successfully edited in the 99.7% of pink cells, while only two of nine among 0.6% of pink cells were correctly edited. The results indicate that the target-mismatched Cpf1 negative selection can assist in efficient and accurate single-base genome editing methods in C. glutamicum.

• Journal of the Korea Computer Industry Society
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• v.4 no.10
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• pp.587-598
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• 2003

This paper construct two-level word similarity relation matrices about title and to scientific treatise. As guide keyword similarity relation matrices which is constructed to co-occurrence frequency base same time keeps recall rater by query expansion by tolerance relation, it is index structure to improve the precision rate by two-level contents base retrieval. Therefore, draw area knowledge through subject analysis and reasoned user's information request and area knowledge to fuzzy logic base. This research is research to improve vocabulary mismatch problem and information expression having essentially on query.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2000.11a
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• pp.63-66
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• 2000

This research addresses study on thermal residual stress of a composite patch repair of the edge cracked aluminium panel of aging aircraft. Composite patch repair is an efficient and economical technique to improve the damage tolerance of cracked metallic structures. These are thermal residual stresses due to the mismatch of coefficient of thermal expansion, and these are affected by the curing cycle of patch specimen. In this study, three curing cycles were selected for F.E. analysis. This study features the effect on composite patch and aluminum by thermal residual stress during crack propagation in aluminum plate.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.41 no.5
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• pp.541-550
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• 1992

The fourth harmonic conversion(FHC) efficiency of high-power Nd laser pulse with wavelength of 1.054x10S0-6Tm using two KDP crystals(doubler adn quadrupler) was simulated numerically. Simulation results show that for the perfect phase-matching condition the FHC efficiency were 60-70% for several hundreds MW/cmS02T class and over 70% for GW/cmS02T class laser pulses. And the overall characteristics of FHC were discussed in terms of effects of input intensity, crystal length, and mismatch angle Δ$\theta$. Optimum method to FHC was type-II doubler & type-I quadrupler KDP crystal because type-II KDP doubler crystal has wide tolerance of acceptance matching-angle.

• Korean Journal of Optics and Photonics
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• v.16 no.3
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• pp.201-208
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• 2005

In order to realize a 3-D stereoscopic display module with alternating illumination angles, several conditions required for a lenticular lens sheet were established, and then both the lens specification and the module structure were designed. Also the performance of the stereoscopic module and its tolerance characteristics were evaluated by simulating the intensity distribution on the observation plane with a finite-ray tracing technique. From the evaluation, it was known that an intersection area between two adjacent lenses should not be filled and that the lateral mismatch between a planar liquid crystal shutter and a lens sheet should be minimized.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.10
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• pp.98-106
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• 1998

Efficient power transmission from a single mode fiber to a thin-film waveguide devices is one of the most fundamental and inevitable subject that should be first solved toward the realization of the integrated optic system. In this paper, fiber-waveguide coupling structure is considered and the large mismatch of field profiles at the fiber-waveguide interface is well avoided by using to the coupling guide which is intentionally developed on the top of the thin-film guuide. From the simulation, the taper-type structure are shown to be easier realizeable than the uniform one, since optical coupling between the guides in the latter has a stronger tolerance to the deviation of waveguide parameters.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.21 no.11
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• pp.1324-1333
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• 2010

In this paper, three kinds of beam coupling losses which occur in a quasi-optics circuit for millimeter wave receiver system have been intensively investigated. First, the beam coupling losses which are caused by mismatch of beam waists radii and their positions between those of one and the other have been evaluated. It shows that beam coupling losses due to mismatch of beam waists radii and their positions between two quasi-optics circuits can be minimized if beam waist radius is chosen as larger than 3 times the operation wavelength. Second, the beam coupling losses have been studied when the axis of propagation of one beam is tilted with respect to that of the other beam. It is noted that smaller beam waist radius results in greater tolerance to tilts and angular misalignments. Third, the beam coupling cases in which two beams are offset if their axes of propagation are parallel but one is displaced relative to the other have been investigated. It is confirmed that beam waists radii with larger than 3 times operation wavelength are less sensitive to lateral offsets.