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열가수분해 및 수열결정화에 의한 구형 ZrO2 분말의 합성 (Synthesis of Spherical ZrO2 Powders by Thermal Hydrolysis and Hydrothermal Crystallization)

  • 조철희;김명희;최재영;김도경
    • 한국세라믹학회지
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    • 제39권4호
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    • pp.420-426
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    • 2002
  • 가열가수분해반응에 의하여 제조된 구형의 $ZrO_2$ 겔을 수열결정화시켜 순수한 $ZrO_2$ 분말과 $Y2_O_3$, CaO 등 상안정화제가 도핑된 $ZrO_2$ 분말을 합성하였다. 합성된 $ZrO_2$ 결정분말들은 평균 10nm 크기의 일차 입자들로 구성된 이차입자들이었다. 이차입자의 평균 크기는 $0.4{\mu}m$였고, 수열결정화과정에서 겔의 구형 형상이 그대로 유지되었으며 일차 입자들 사이에는 약한 응집으로 존재하였다. 입자모양, 크기, 상분율, 도핑된 분율 등을 SEM, TEM, XRD, ICP로 연구하였고 구형 겔의 수열결정화기구를 논의하였다.

Disorders of Secondary Neurulation : Mainly Focused on Pathoembryogenesis

  • Yang, Jeyul;Lee, Ji Yeoun;Kim, Kyung Hyun;Wang, Kyu-Chang
    • Journal of Korean Neurosurgical Society
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    • 제64권3호
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    • pp.386-405
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    • 2021
  • Recent advancements in basic research on the process of secondary neurulation and increased clinical experience with caudal spinal anomalies with associated abnormalities in the surrounding and distal structures shed light on further understanding of the pathoembryogenesis of the lesions and led to the new classification of these dysraphic entities. We summarized the changing concepts of lesions developed from the disordered secondary neurulation shown during the last decade. In addition, we suggested our new pathoembryogenetic explanations for a few entities based on the literature and the data from our previous animal research. Disordered secondary neurulation at each phase of development may cause corresponding lesions, such as failed junction with the primary neural tube (junctional neural tube defect and segmental spinal dysgenesis), dysgenesis or duplication of the caudal cell mass associated with disturbed activity of caudal mesenchymal tissue (caudal agenesis and caudal duplication syndrome), failed ingression of the primitive streak to the caudal cell mass (myelomeningocele), focal limited dorsal neuro-cutaneous nondisjunction (limited dorsal myeloschisis and congenital dermal sinus), neuro-mesenchymal adhesion (lumbosacral lipomatous malformation), and regression failure spectrum of the medullary cord (thickened filum and filar cyst, low-lying conus, retained medullary cord, terminal myelocele and terminal myelocystocele). It seems that almost every anomalous entity of the primary neural tube may occur in the area of secondary neurulation. Furthermore, the close association with the activity of caudal mesenchymal tissue in secondary neurulation involves a wider range of surrounding structures than in primary neurulation. Although the majority of the data are from animals, not from humans and many theories are still conjectural, these changing concepts of normal and disordered secondary neurulation will provoke further advancements in our management strategies as well as in the pathoembryogenetic understanding of anomalous lesions in this area.

Korean Red Ginseng and Rb1 facilitate remyelination after cuprizone diet-induced demyelination

  • Oh Wook Kwon;Dalnim Kim;Eugene Koh;Hyun-Jeong Yang
    • Journal of Ginseng Research
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    • 제47권2호
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    • pp.319-328
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    • 2023
  • Background: Demyelination has been observed in neurological disorders, motivating researchers to search for components for enhancing remyelination. Previously we found that Rb1, a major ginsenoside in Korean Red Ginseng (KRG), enhances myelin formation. However, it has not been studied whether Rb1 or KRG function in remyelination after demyelination in vivo. Methods: Mice were fed 0.2% cuprizone-containing chow for 5 weeks and returned to normal chow with daily oral injection of vehicle, KRG, or Rb1 for 3 weeks. Brain sections were stained with luxol fast blue (LFB) staining or immunohistochemistry. Primary oligodendrocyte or astrocyte cultures were subject to normal or stress condition with KRG or Rb1 treatment to measure gene expressions of myelin, endoplasmic reticulum (ER) stress, antioxidants and leukemia inhibitory factor (LIF). Results: Compared to the vehicle, KRG or Rb1 increased myelin levels at week 6.5 but not 8, when measured by the LFB+ or GST-pi+ area within the corpus callosum. The levels of oligodendrocyte precursor cells, astrocytes, and microglia were high at week 5, and reduced afterwards but not changed by KRG or Rb1. In primary oligodendrocyte cultures, KRG or Rb1 increased expression of myelin genes, ER stress markers, and antioxidants. Interestingly, under cuprizone treatment, elevated ER stress markers were counteracted by KRG or Rb1. Under rotenone treatment, reduced myelin gene expressions were recovered by Rb1. In primary astrocyte cultures, KRG or Rb1 decreased LIF expression. Conclusion: KRG and Rb1 may improve myelin regeneration during the remyelination phase in vivo, potentially by directly promoting myelin gene expression.

Status of Philippine Mango Genomics: Enriching Molecular Genomics Towards a Globally Competitive Philippine Mango Industry

  • Eureka Teresa M. Ocampo;Cris Q. Cortaga;Jhun Laurence S. Rasco;John Albert P. Lachica;Darlon V. Lantican
    • 한국작물학회:학술대회논문집
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    • 한국작물학회 2022년도 추계학술대회
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    • pp.28-28
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    • 2022
  • This paper presents the first genome assemblies of Philippine mangoes that provide valuable reference for varietal improvement and genomic studies on mango and related fruit crops. WE sequenced whole genomes of3 species, Mangifera odorata (Huani), Mangifera altissima (Paho), and Mangifera indica 'Carabao' (Sweet Elena). 'Carabao' is the major export variety of the Philippines; Paho is identified as vulnerable by the IUCN Red List of Threatened Species; Huani has fruit sap acrid which is the primary defense mechanism against insects and birds. We used Falcon, a diploid aware -de novo assembler to assemble SMRT generated long-read sequences. Falcon-unzip was employed to phase the output assembly producing larger contig sets (primary contigs) and shorter contigs corresponding to haplotypes (haplotigs). Assembly statistics were generated by comparing the assembly to a reference genome, Tommy Atkins, using Quality Assessment Tool (QUAST). Moreover, the extent of duplication and completeness of gene content was measured using Benchmarking Universal Single-Copy Orthologs (BUSCO). Draft assemblies with high duplications were processed using Purge Haplotigs and Purge Dups to lessen duplications with minimal impact on genome completeness. De novo assemblies of Huani, Paho and 'Carabao' were then generated with primary contig sizes of 463.64 Mb, 508.95 Mb and 401.51 Mb respectively. These draft assemblies of Huani, Paho and 'Carabao' showed 96.90%, 95.17% and 99.07% complete BUSCOs respectively which is comparable to 'Tommy Atkins' genome (98.6%). Using two mango transcriptome data (pooled RNA-seq from different mango varieties and tissues), 91-96% or 24-30 million reads were successfully mapped back for each generated assembly indicating high degree of completeness. The results obtained demonstrated the highly contiguous, phased, and near complete genome assembly of three Philippine mango species for structural and functional annotation of gene units, especially those with economic importance.

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Studies on the Fruiting Phase of Rape Under the Different Cultural Conditions

  • Kae, B.M.
    • 한국작물학회지
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    • 제12권
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    • pp.77-87
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    • 1972
  • The fruiting phase of rape under transplanting and direct-sowing conditions has been studied at Mokpo during the 2 years period from 1970 to 1971. Two varieties, Yudal and Miyuki were used in this study. The planting space and sowing time were also incorporated into this study. The results could be summarized as follows: 1. The plant tape of rape was nearly umbrella-shaped of all, but has changed to the laid elliptical-shaped, broadly ovate and spindle-shaped under different varieties and cultural conditions in the plant diagram(Fig. 2). 2. The length of the primary branches for each nodes had a tendency to the symmetric apical curve with the apex at the upper 10-12th node in the transplanting. but to the upper bias apical curve with the apex at the upper 5-7th node in the dense-sowing(Fig.3). 3. The ear of main stem was longer, more pods, heavier 1, 000 grains and more grain yield than ear of primary branches of all, Especially, as for that, the rate of yield constitution per plant in the direct-sowing was higher than in the transplanting(Fig. 4, 5, 6, 7, 8, 9). 4. The ear-length of the primary branches for each nodes had a tendency to the relatively slowly apical curve with the apex at the upper 3-4th node in the transplanting, but to the lower bias apical curve with the apex at the upper 2nd node in the dense-sowing. Especially, the possibility of growth at the lower ears was few in the early variety (Fig. 4). 5. The number of pod per ear on the primary branches for each nodes had a .tendency to the curve of ear-length with the apex at the upper 5-8thnode in the transplanting and at the upper 4-5th node in the dense-sowing (Fig. 5). Accordingly, a high positive correlation was found between the ear-length and number of pod per ear (Table 2) 6. In the transplanting, the high rate of effective ear was from the upper nods to the 12th node, but below the 16-17th nodes was ineffective. However, in the early dense-sowing the high rate of effective was to the 7th node. but below the 10th nodes was. ineffective. Especially, in the early variety has difficult to secure of poi-numbers for ineffective of the lower nodes(Fig. 6.). 7. The density of pod setting of the ear of main stem was the longest of all ears, and the lower nods were, the shorter it became. That had a tendency to the evidently apical growth. However. in the early variety, it was lengthened according to growth of ear-length(Fig.7). 8. The pod-length of the medium nodes was longer than the upper and lower, and the possitive correlation between pod-length and number of grain per poi was very high(Table 2.). 9. In the grain yield per node of primary branches, the most yielding node of transplanting was the upper 9th node, of dense-sowing 4-5th node(Fig 8.), and the possitive correlation between grain yield per node and ear-length or number of pod per ear was very high(Table 2). 10. The grain yield of ear of main stem was higher than that of primary branches in the percentage of dependence for grain yield per plant. The limint node of 50% of dependence to cumulative grain yield per plant was the upper 7-8th node in tranplanting, in the early dense-sowing 4-5th node, and in tke late dense-sowing-3th node(Fig. 9). 11. In the weight of 1, 000 grains the lower nodes were, the lighter it becames in dense-sowing. Therefore, this was also lighter than in the transplanting to the (Fig. 10.). 12. The oil content of grain at the medium nodes was low in the early variety, but at the ear of main stem and upper 1st node it was extremely high(Fig. 11.).

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뇌졸중 환자의 질병경험에 관한 연구 (A Study of CVA patients에 Experience of the Illness)

  • 남선영
    • 대한간호학회지
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    • 제28권2호
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    • pp.479-489
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    • 1998
  • This work was done for 9 patients having experience of a herb medical treatment after being diagnosed as CVA during a year from January, 1996 to December, 1996 by using an ethnographic research method. The summarized results of this research are following. Ⅰ. THE EXPERIENCE OF THE ILLNESS First, the falling-ill phase is the time that they have the first stroke of paralysis and the decision pattern of medical institution' comes out. The emotional experience in the period is something like 'flustration', 'anxiety', 'despair', and 'expectation'. Second, the active-treatment phase is the time that the patients as well as their family or care giver not only show the positive attitude and actively participate in the illness treatment but also show a lot of interest in medical institutions and activities of health recovery. There is a primary factor of the continuation of treatment as an experience of treatment and being crushed and sensitivity as an experience of the illness. Third, the rehabilitation phase is the time that the patients or their family become tired and insensitive to the treatment and recuperation, and then reduce the treatment activity. There is a primary influence factor of the discontinuance of treatment as an experience of treatment and physical experience and emotional experience as an experience of the illness. The physical experience is divided into 'personal-hygiene care', and 'the sphere of activity' The emotional experiences are 'blaming someone', 'contempt' and 'despair' as a negative experience and 'hope' as a positive experience. Ⅱ. COPING STRATEGY There are a physical coping, an emotional and mental coping, a social coping, and a spiritual coping as a coping strategy used for the patients to overcome their illness and adjust themselves to their altered life. First, the physical coping comes out as 8 categories, 'using an auxiliary tool', 'doing exercise', 'protecting', 'improving their diet', 'taking care of something', 'using subsidiary medicines', 'trying a folk remedy', and 'having interest in their health'. Second, for the emotional and mental coping, there are 'accepting' and 'trying' as a positive coping and a failure of control as a negative coping. Third, the social coping is appeared as 'being supported'. Fourth, the spiritual coping is recognized as' recourse to God' and 'preparation of death'. After all, the elderly CVA patients in an agricultural area choose the act of treatment based on the traditional belief and the relationship with a caretaker. A personal health can be maintained by taking care of themselves and controling their mind, and the overcome of the illness is decided on the basis of traditional concepts and cultural principles in which the patients as well as the family, neigbors and take carers should work out together and cooperate with each other in order to achieve that.

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큰발웃수염박쥐 (Myotis macrodactylus)의 정상피세포의 분화와 미세구조 (Cell Differentiation and Ultrastructure of the Seminiferous Epithelium in Myotis macrodactylus)

  • 이정훈
    • Applied Microscopy
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    • 제33권1호
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    • pp.25-39
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    • 2003
  • 큰발웃수염박쥐 (Myotis macrodactylus)의 세정관 정상피의 분화과정과 미세구조적 특징들은 알아보기 위하여 광학 및 전자현미경을 이용하여 조사하였다. 정자형성 과정은 4월부터 9월까지로 나타났다. 정자형성세포의 미세 구조적 특징에 있어서, A형 (Ad, Ap)의 정원세포는 기저막 위에 위치하며, Sertoli cell에 의해 둘러싸여져 있고, 대부분의 세포는 타원형이다. Ad형은 Ap형 보다 핵과 세포질의 전자밀도가 높은 것이 특징적인 반면에, B형의 정원세포는 구형의 세포로서 A형 정원세포 보다 세포가 크며, Ap형과 마찬가지로 세포질이 밝고, 거의 핵소체가 핵막에 인접되어 있다. 정모세포는 크고 구형이지만, 제 1 정모세포가 제 2 정모세포보다 다소 크다. 정자변태는 골지, 두모, 첨체, 성숙 및 이탈기로 구분하였고, 세포구조물의 특징들에 의해 각각 전 후기로 다시 세분하여 전과정을 9 (기)로 나누었다. 핵질의 변화는 골지후기부터 서서히 응축하기 시작하여, 이탈기에서 완전한 핵을 형성하였다. 정자꼬리의 형성시기는 골지전기에서 형성하기 시작하여 이탈기에서 완성되었다. 동면직전 10월부터 동면기 (11월, 12월, 이듬해 1, 2, 3월)까지는 정자형성 세포의 퇴화과정이 일어났다. 즉 미분화 정자형성 세포들은 세르톨리 세포의 식작용에 의해 포식되어졌는데 이는 동면을 위한 에너지 효율적 이용과 번식조절을 위한 적응 메카니즘이라 여겨진다.

Loran 신호 이용 통신망 동기를 위한 타이밍 신호 보상 방안 (A Compensation Method of Timing Signals for Communications Networks Synchronization by using Loran Signals)

  • 이영규;이창복;양성훈;이종구;공현동
    • 한국통신학회논문지
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    • 제34권11A호
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    • pp.882-890
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    • 2009
  • 본 논문에서는 Loran 신호를 이용하여 원거리통신망 및 전력 분배망과 같은 국가 기반 산업에 대한 망동기를 이루고자 할 때에 Loran 수신기에서 수신한 신호에 대한 위상 동기를 잃어 버렸을 때 이를 보상하기 위한 방안에 대해서 논한다. Loran 수신기에서 위상 동기를 잃었을 때에는 수신기 내에 있는 오실레이터가 자유구동을 하게되고, 따라서 이를 기준으로 출력되는 타이밍 동기신호의 성능이 크게 떨어지게 되며, 이때에 ITU G.811 표준에서 요구하는 PRC에 대한 1 us 이하의 요구 성능을 만족시킬 수 없게 된다. 따라서 본 논문에서는 Loran 수신기가 위상 동기를 잃었을 때 이를 보상하기 위해 보상 알고리즘을 사용하여 위상 점프를 보상하는 방법에 대해 제안했으며, 이에 대해 실측한 데이터에 대한 MTIE 성능을 분석하였다. 성능 분석 결과 제안된 방법을 사용하면 1시간 간격으로 동기를 잃었을 경우에 30 분 평균 이하의 스무딩 값을 사용할 경우 대략 0.6 us 이하의 MTIE 값을 보여서 산업체 표준에서 요구하는 1 us 이내의 PRC 성능을 충분히 만족시킬 수 있음을 확인하였다.

알루미늄과 마그네슘 첨가가 용융아연 도금강판 도금층의 미세조직과 경도에 미치는 영향 (Effects of Al and Mg on the Microstructure and Hardness of the Coating Layer of Hot-dip Galvanized Steel Sheet)

  • 성윤제;김동규;서준기;한경현;홍범기;김강민;허성욱;박성현;임재택;손승배;이석재;정재길
    • 열처리공학회지
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    • 제36권4호
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    • pp.198-205
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    • 2023
  • We investigated the effects of Al and Mg on the microstructure and hardness of the coating layer of galvanized steel sheets, by thermodynamic calculations, X-ray diffraction, scanning electron microscopy, and Vickers hardness tests of Zn-0.2Al, Zn-6Al-2Mg, and Zn-10Al-5Mg coating layers. Regardless of the alloy composition of the galvanizing bath, a Fe-Al layer was observed between the coating layer and steel sheet. The Zn-0.2Al coating layer consists of major h.c.p. Zn phase and minor f.c.c. Al phase. The fraction of f.c.c. Al phase (containing a significant amount of Zn) of the coating layer increases with increasing the chemical composition of Al of the galvanizing bath. The h.c.p. MgZn2 phase was formed in the Al/Mg-containing Zn-6Al-2Mg and Zn-10Al-5Mg coating layers, forming Zn-Al-MgZn2 eutectic microstructure. The primary MgZn2 phase was additionally formed in the Zn-10Al-5Mg coating layers containing high concentrations of Al and Mg. The Vickers hardness values of Zn-0.2Al, Zn-6Al-2Mg, and Zn-10Al-5Mg coating layers were 59.1 ± 1.2 HV, 161.2 ± 5.7 HV, and 215.5 ± 40.3 HV, respectively. The addition of Al and Mg increased the hardness of the coating layer by increasing the fraction of the Al phase (containing Zn) and MgZn2 intermetallic compound, which were harder than the Zn phase.

Investigation and Implementation of a Passive Snubber with a Coupled-Inductor in a Single-Stage Full-Bridge Boost PFC Converter

  • Meng, Tao;Ben, Hongqi;Li, Chunyan;Wei, Guo
    • Journal of Power Electronics
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    • 제13권2호
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    • pp.206-213
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    • 2013
  • In this paper, an improved passive snubber is investigated in a single-phase single-stage full-bridge boost power factor correction (PFC) converter, by which the voltage spike across primary side of the power transformer can be suppressed and the absorbed energy can be transferred to the output side. When compared with the basic passive snubber, the two single-inductors are replaced by a coupled-inductor in the improved snubber. As a result, synchronous resonances in the snubber can be achieved, which can avoid the unbalance of the voltage and current in the snubber. The operational principle of the improved passive snubber is analyzed in detail based on a single-phase PFC converter, and the design considerations of both the snubber and the coupled-inductor are given. Finally, a laboratory-made prototype is built, and the experimental results verify the feasibility of the proposed method and the validity of the theoretical analysis and design method.