• Bulletin of the Korean Chemical Society
• /
• v.25 no.1
• /
• pp.90-96
• /
• 2004

The conformations of dicyclopropyl, isopropyl cyclopropyl, and diisopropylcarbenes were optimized using density functional theory (B3LYP/6-31G(d)). We showed that the optimized geometries of carbenes with cyclopropyl groups are fully in accord with those expected for bisected W-shaped conformations, in which the effective hyperconjugation of a cyclopropyl group with singlet carbene can occur. The stabilization energies were evaluated at the B3LYP/6-311+G(3df, 2p)//B3LYP/6-31G(d) + ZPE level using an isodesmic equation. The relative stability of carbenes is in the order $(c-Pr)_2$C: > (i-Pr)(c-Pr)C: > $(i-Pr)_2$C:, and a cyclopropyl group stabilizes carbene more than an isopropyl group by nearly 9 kcal/mol. Energies for the decomposition of diazo compounds to carbenes increase in the order $(c-Pr)_2$ < (i-Pr)(c-Pr) < $(i-Pr)_2$ by ~9 kcal/mol each. From a singlettriplet energy gap ($E_{ST}$) calculation, the singlet level is lower than the triplet level and the $E_{ST}$ shows a trend similar to the stabilization energy calculations. For comparison, the optimized geometries and stabilization energies for the corresponding carbocations were also studied at the same level of calculation. The greater changes in geometries and the higher stabilization energies for carbocations compared to carbenes can explain the greater hyperconjugation effect.

• Clinical and Experimental Reproductive Medicine
• /
• v.27 no.3
• /
• pp.301-305
• /
• 2000

Globozoospermia is a rare type of teratozoospermia. It occurs in 0.1% of all andrological patient's and used to be considered sterile. Globozoospermic patient has 100% round headed spermatozoa, but the spermiogram is normal. The spermatozoa show oval-shape head, the lack of a nuclear envelope, acrosome, and post acrosomal sheath. Objective: To report that a couple with infertility secondary to globozoospermia received ICSI treatment. Material and Method: Case report Results: In the first trial, fertilization was failed. In the second trial, 40% of oocytes were fertilized and all of these embryos were cleaved, but pregnancy did not achieved. In the third trial, sperm injected oocytes were exposed to 10 ${\mu}M$ calcium ionophore for 15 min. All of the injected oocytes were fertilized and proceeded to develop. Triplet pregnancy was achieved after the transfer of six embryos in their third cycle. One embryo vanished and the remaining twins (female) were delivered at 33 weeks of gestation by Caesarean section. Conclusion: This result shows that assisted activation following ICSI may overcome infertility associated with globozoospermia.

• Korean Journal of Optics and Photonics
• /
• v.6 no.3
• /
• pp.178-187
• /
• 1995

The method that determines the appropriate damping factor is studied for a lens design. When suitable damping factor is applied to the additive damped least-squares (DLS) method, the convergence and the stability of the optimization process are examined in a triplet-type photographic lens design. We calculate eigenvalues of the product of the Jacobian matrix of error functions by using the singular value decomposition (SVD) method. We adopt the median of eigenvalues as an appropriate damping factor. The convergence and the stability of the optimization process are improved by choosing the adequate damping factor for the optimization of a photographic lens. It is known that the numerical inaccuracy in the calculation of normal equation is overcome by using the orthogonal transformations of the Jacobian matrix. Therefore, a combination of the method for setting a proper damping factor and the orthogonal transformations of the Jacobian matrix is good for application to the design of an aspheric lens with high-order terms. terms.

• The Plant Pathology Journal
• /
• v.27 no.1
• /
• pp.33-36
• /
• 2011

The genome of a potyvirus isolate associated with chlorotic spots and vein banding symptoms on Spathiphyllum spp., in Andhra Pradesh state, India was amplified by RT-PCR using degenerate potyvirus primers, amplicons cloned, and sequence (1.6 kb) analyzed. This virus isolate shared maximum identity of 74.8% and 80.2% at coat protein (CP) gene nucleotide (906 nucleotides) and amino acid (302 amino acids) levels, respectively with Dasheen mosaic virus (DsMV)-M13 isolate reported from China. But its 3'-UTR (258 nucleotides) had maximum identity of 62.5% with DsMV-Vietnam isolate. The deduced molecular weight of CP is 33.57 kDa and it contained DAG triplet in its N-terminal region. In CP amino acid based phylogenetic analysis, this virus isolate represented a separate branch but closer to DsMV isolates cluster. Based on the molecular criteria set for the discrimination of species and genus in the Potyviridae family, the present virus isolate was identified as a distinct virus species in the genus Potyvirus and proposed the name Spathiphyllum chlorotic vein banding virus (SCVbV).

• Journal of the Korean Applied Science and Technology
• /
• v.19 no.2
• /
• pp.97-102
• /
• 2002

Recently, the phosphorescent organic light-emitting devices (OLEDs) have been extensively studied for their high internal quantum efficiency. In this study, we synthesised several phosphorescent metal complexes, and certified their composition using NMR. We also investigated the characteristics of the phosphorescent OLEDs with the green emitting phosphor, $Ir(ppy)_{3}$. The devices with a structure of indium-tin-oxide(ITO)/N,N'-diphenyl-N,N'-(3-methylphenyI}-1,1'-biphenyl-4,4'-diamine (TPD)/metal complex doped in host materials/2,9-dimethyl-4,7-diphenyl-l,10-phenanthroline(BCP)/tris (8-hydroxyquinolinato) Aluminum($Alq_{3}$)/Li:Al/Al was fabricated, and its electrical and optical characteristics were studied. By changing the doping concentration of tris(2-phenylpyridine)iridium ($Ir(ppy)_{3}$), we fabricated several devices and investigated their characteristics.

• Bulletin of the Korean Chemical Society
• /
• v.15 no.9
• /
• pp.743-748
• /
• 1994

Photochemical reactions of saccharin with tertiary amines were explored. Saccharin was found to undergo an acid-base reaction with N-trimethylsilylmethyl-N,N-diethyl amine to form N-trimethylsilylmethyl-N,N-diethyl ammonium saccharin salt which is in equilibrium with free saccharin and N-trimethylsilylmethyl-N,N-diethyl amine insolution. Photoreaction of N-trimethylsilylmethyl-N,N-diethyl ammonium saccharin in $CH_3OH\;or\;CH_3CN$ results in the generation of desilylmethylated product, N,N-diethyl ammonium saccharin mainly along with benzamide. Photoreaction of N-methylsaccharin with N-trimethylsilylmethyl-N,N-diethyl amine in $CH_3OH$ leads to the production of o-(N-methylcarbamoyl)-N-ethylbenzenesulfonamid e as the major product along with N-methylbenzamide as the minor product. On the other hand, photoreaction of N,N,N-triethyl ammonium saccharin, generated from saccharin and triethylamine, produces N-methylbenzamide as the exclusive product. These photoreactions are quenched by oxygen indicating that triplets of saccharin and N-methylsaccharin are the reactive excited states. Based on the consideration of the redox potentials of saccharin and N-trimethylsilylmethyl-N,N-diethyl amine, and the nature of photoproducts, pathways involving initial triplet state single electron transfer are proposed for photoreactions of the saccharins with the ${\alpha}$-silylamine.

• Journal of Korea Multimedia Society
• /
• v.24 no.10
• /
• pp.1380-1390
• /
• 2021

The video face recognition (FR) is one of the most popular researches in the field of computer vision due to a variety of applications. In particular, research using the attention mechanism is being actively conducted. In video face recognition, attention represents where to focus on by using the input value of the whole or a specific region, or which frame to focus on when there are many frames. In this paper, we propose a novel attention based deep learning method. Main novelties of our method are (1) the use of combining two loss functions, namely weighted Softmax loss function and a Triplet loss function and (2) the feasibility of end-to-end learning which includes the feature embedding network and attention weight computation. The feature embedding network has a positive effect on the attention weight computation by using combined loss function and end-to-end learning. To demonstrate the effectiveness of our proposed method, extensive and comparative experiments have been carried out to evaluate our method on IJB-A dataset with their standard evaluation protocols. Our proposed method represented better or comparable recognition rate compared to other state-of-the-art video FR methods.

• Progress in Superconductivity and Cryogenics
• /
• v.23 no.2
• /
• pp.10-13
• /
• 2021

Superconductor-ferromagnet thin film heterostructure is an ideal system for studying the interplay between superconductivity and ferromagnetism. These two antagonistic properties combined in thin film heterostructure create interesting proximity effects such as spin-triplet superconductivity. Thin film heterostructure of optimally doped La_2-xSr_xCuO₄(LSCO) cuprate superconductor and SrRuO₃(SRO) ruthenate ferromagnet has been grown by pulsed laser deposition. Its temperature-dependent resistivity and Hall effect measurements show that our LSCO/SRO heterostructure has both superconductivity and ferromagnetism. In the Hall effect measurement results, we find additional hump-like structures appear in the anomalous Hall effect signal in the vicinity of superconducting transition. We conclude that giant magnetoresistance of the LSCO layer distorts the AHE signal, which results in a hump-like structure.

• Annual Conference on Human and Language Technology
• /
• 2023.10a
• /
• pp.491-496
• /
• 2023

사전학습 언어모델을 개선하여 고품질의 문장 표현(sentence representation)을 도출하기 위한 다양한 대조 학습 방법에 대한 연구가 진행되고 있다. 그러나, 대부분의 대조학습 방법들은 문장 쌍의 관계만을 고려하며, 문장 간의 유사 정도를 파악하는데는 한계가 있어서 근본적인 대조 학습 목표를 저해하였다. 이에 최근 삼중항 손실 (triplet loss) 함수를 도입하여 문장의 상대적 유사성을 파악하여 대조학습의 성능을 개선한 연구들이 제안되었다. 그러나 많은 연구들이 영어를 기반으로한 사전학습 언어모델을 대상으로 하였으며, 한국어 기반의 비지도 대조학습에 대한 삼중항 손실 함수의 실효성 검증 및 분석은 여전히 부족한 실정이다. 본 논문에서는 이러한 방법론이 한국어 비지도 대조학습에서도 유효한지 면밀히 검증하였으며, 다양한 평가 지표를 통해 해당 방법론의 타당성을 확인하였다. 본 논문의 결과가 향후 한국어 문장 표현 연구 발전에 기여하기를 기대한다.

• Asian-Australasian Journal of Animal Sciences
• /
• v.5 no.4
• /
• pp.717-722
• /
• 1992

An experiment was conducted to examine the feasibility of producing multiple calves using embryo transfer in Japanese Black cattle. Milk yield of cows and forage intake of calves were measured for 11 cows with single calves, 14 cows with twins and one cow with triplets. The means of 26 weeks cumulative milk yield were 854, 1028 and 1271 kg for cows having singles, twins and triplets, respectively. Male birth weights for single calves, twins and triplet were 34.9, 26.6 and 19.9 kg, and female ones were 31.7, 24.1 and 22.1 kg, respectively. Weight and daily gain of calves were affected by weeks (W), sex (S), the number of calves (N), parity, birth season, $W{\times}N$, $S{\times}N$ and regression on milk yield. Growth rate was higher for single calves than for twins until about 9 weeks of age, then weights increased at a similar rate. Male calf weaning weights for singles, twins and triplets were 207.0, 177.1 and 162.2 kg, and those for females were 185.4, 151.6 and 180.4 kg, respectively. Average regression coefficients of calf growth on milk yield were significant, and single calf was affected more than twin calves by increment of milk yield. As the number of calves per cow increased, hay intake of calves decreased and concentrate intake tended to increase between 6 and 13 weeks of age.