Understanding of effects of changes in the particle size of the matrix material on the mullite whisker growth during the production of porous mullite is crucial for better design of new porous ceramics materials in different applications. Commercially, raw materials such as Al2O3/SiO2 and Al(OH)3/SiO2 are used as starting materials, while AlF3 is added to fabricate porous mullite through reaction sintering process. When Al2O3 is used as a starting material, a porous microstructure can be identified, but a more developed needle shaped microstructure is identified in the specimen using Al(OH)3, which has excellent reactivity. The specimen using Al2O3/SiO2 composite powder does not undergo mulliteization even at 1,400 oC, but the specimen using the Al(OH)3/SiO2 composite powder had already formed complete mullite whiskers from the particle size specimen milled for 3 h at 1,100 oC. As a result, the change in sintering temperature does not significantly affect formation of microstructures. As the particle size of the matrix materials, Al2O3 and Al(OH)3, decreases, the porosity tends to decrease. In the case of the Al(OH)3/SiO2 composite powder, the highest porosity obtained is 75% when the particle size passes through a milling time of 3 h. The smaller the particle size of Al(OH)3 is and the more the long/short ratio of the mullite whisker phase decreases, the higher the density becomes.

최근 기업들의 해외시장진출이 활발해지면서 글로벌 시장에서의 신제품개발속도에 대한 관심이 높아지고 있다. 본 연구는 신제품개발속도를 글로벌 관점에서 살펴보고, 더 나아가 기업특성과 시장 환경 특성이 글로벌 시장에서의 신제품개발속도에 미치는 영향을 실증적으로 분석하고자 한다. 이를 위해 한국 제조업체들을 대상으로 신제품개발 및 제품 성과에 대한 설문조사를 실시하였다. 실증분석 결과, 기업 및 시장 환경 특성 중에서도 기업 규모, 제품특성, 시장불확실성이 글로벌 시장에서의 신제품개발속도에 유의미한 영향을 미치는 것으로 나타났다. 이에 본 연구는 글로벌적 관점에서 신제품개발속도에 영향을 미치는 요인들을 검증함으로써 학문적 및 실무적 관점에서 의미있는 시사점을 제공할 수 있을 것으로 기대된다.

This research aims to study the simultaneous extraction and transesterification of Chlorella vulgaris (C. vulgaris) using microwave irradiation with methanol as solvent and potassium hydroxide (KOH) as catalyst. The microwave-assisted insitu transesterification of C. vulgaris is assessed at various ratios of biomass-to-methanol, reaction times, and catalyst concentrations during the centrifugation and evaporation process. Gas chromatography-mass spectrometry (GC-MS) analysis is performed to confirm fatty acid methyl ester (FAME) composition. Biodiesel preparation is carried out by simultaneous extraction and transesterification of microalgae from C. vulgaris. The product is then characterized using Fourier transform infrared spectroscopy (FTIR) and proton nuclear magnetic resonance (1H-NMR); microalgae are observed using scanning electron microscopy (SEM). The highest amount of FAME is obtained at a biomass-to-methanol ratio of 1:12, reaction time of 40 min, and catalyst concentration of 2 wt%. Biodiesel shows conversion to about 77.64% of methyl ester (methyl myristate, methyl palmitoleate, methyl linoleate, methyl oleate, methyl arachidonate, and methyl 5,8,11,14,17-eicosapentanoate).

Embryonic lethality due to recessive alleles is a major concern in livestock breeding programs. The Online Mendelian Inheritance in Animal (OMIA) is a database of reported recessive mutations in livestock that helps breeders to manage the segregation of these mutations in their population. Recessive alleles are lethal in the offspring of two carrier parents; therefore, identifying and eliminating carrier animals are critical for maintaining the breed. Hanwoo cattle is native to the Korean peninsula and is of great economic importance to Korea. Due to geographical constraints and the controlled breeding program with very few proven bulls, if not monitored periodically, the threat of segregation of recessive lethal alleles in the population remains high. Therefore, identifying potential carriers of lethal recessive alleles is critical in Hanwoo. In this regard, we genotyped 17,325 animals using bovine 50K Illumina SNP chip and also sequenced a further 311 animals which was mapped against the bovine reference genome sequence. We then used the OMIA database to identify reported recessive alleles and calculated the allele frequency of these mutations in the population to determine potential lethal alleles carried by the animals.

The important thing in the field of deep learning is to find out the appropriate hyper-parameter for image classification. In this study, the main objective is to investigate the performance of various hyper-parameters in a convolutional neural network model based on the image classification problem. The dataset was obtained from the Kaggle dataset. The experiment was conducted through different hyper-parameters. For this proposal, Stochastic Gradient Descent without momentum (SGD), Adaptive Moment Estimation (Adam), Adagrad, Adamax optimizer, and the number of batch sizes (16, 32, 64, 120), and the number of epochs (50, 100, 150) were considered as hyper-parameters to determine the losses and accuracy of a model. In addition, Binary Cross-entropy Loss Function (BCLF) was used for evaluating the performance of a model. In this study, the VGG16 convolutional neural network was used for image classification. Empirical results demonstrated that a model had minimum losses obtain by Adagrad optimizer in the case of 16 batch sizes and 50 epochs. In addition, the SGD with a 32 batch sizes and 150 epochs and the Adam with a 64 batch sizes and 50 epochs had the best performance based on the loss value during the training process. Interestingly, the accuracy was higher while performing the Adagrad and Adamax optimizer with a 120 batch sizes and 150 epochs. In this study, the Adagrad optimizer with a 120 batch sizes and 150 epochs performed slightly better among those optimizers. In addition, an increasing number of epochs can improve the performance of accuracy. It can help to create a broader scope for further experiments on several datasets to perceive the suitable hyper-parameters for the convolutional neural network. Dataset: https://www.kaggle.com/c/dogs-vs-cats/data

본 논문은 산문 “Magic,” “Swedenborg, Mediums, and the Desolate Places,” Per Amica Silentia Lunae와 A Vision에 나타난 예이츠의 영성에 대한 생각을 살펴보는데 그 목적이 있다. 우선 본격적인 논의에 앞서, 이 논문은 예이츠가 유년 시절에 접했던 민담과 아버지의 기성 종교에 대한 비판과 같은 예이츠 특유의 영성을 형성한 여러 가지 요소들에 대하여 살펴본다. 이러한 유년 시절의 영향은 예이츠로 하여금 기성 종교와 대비되는 대안적인 형태의 영성을 추구하게 만들었으며 이는 신지 학회와 황금여명회 가입으로 이어진다. 이는 또한 예이츠가 아일랜드의 민담과 전설 등 아일랜드의 고유한 전통에 바탕을 둔 특유의 영성 이론을 발전시키는데 도움을 준다. 다음으로, 논문은 예이츠의 1901년 에세이 “Magic”부터 영성에 대한 추구가 집대성 되어 있다고 볼 수 있는 A Vision에 이르기까지의 예이츠의 산문을 살펴봄으로써 예이츠가 어떠한 방식으로 영성에 대한 생각을 글로써 표현하고자 하였는지에 대하여 논의하고자 한다.