Intrusion of a Magnetic Field through the Overlying Field in the Solar Atmosphere Induced by Ballooning Instability

Hongda,Jun1,G.S.Choe 한국천문학회 2010 天文學會報 Vol.35 No.1

Role of magma differentiation depth in the formation of Au-rich porphyry deposits

Hongda Hao,Jung-Woo Park 대한지질학회 2021 대한지질학회 학술대회 Vol.2021 No.10

Porphyry deposits, the world’s most significant source of Cu and an important source of Au, are formed by precipitation of Cu and Au from magmatic hydrothermal fluids. It has been recognized that the Au endowments are highly variable in porphyry systems and high Au grades will significantly increase the deposits value. However, the key factors that control the variability of Au grades in porphyry deposits remains unclear. Magmas that undergo differentiation in deep crustal reservoirs are likely to become sulfide-saturated early, due to the high-pressure and low Fe content, which decrease the sulfur solubility in silicate melts. Early sulfide saturation causes most of Au and some Cu to be locked in the sulfide phases that are retained in the lower crustal cumulates. The evolving magma will be significantly depleted in Au, but it probably contain enough Cu to form a porphyry Cu-dominant deposit. In contrast, magmas evolving in shallow reservoirs are suggested to reach sulfide saturation late, so that most of the Cu and Au will be available by the time of fluids exsolution, favoring the formation of Au-rich porphyry deposits. Based on this relationship, we compile the global Au grade and magma differentiation depth, represented by La/Yb ratios, of giant porphyry deposits and show they are generally negatively correlated. As a consequence, we suggest that the Au fertility, which is dominantly controlled by the timing sulfide saturation and magma differentiation depth, plays an important role in the formation of Au-rich porphyry deposits.

Novel SPG4 Mutation in a Patient with Sporadic Hereditary Spastic Paraplegia and Elevated Cerebrospinal Fluid Protein

Hongda She,Xin Zheng,Yingxiu Xiao,Frank Mastaglia,Anthony Akkari,Jingshan Wu 대한신경과학회 2021 Journal of Clinical Neurology Vol.17 No.1

Influence of chalcophile element fertility on the post-collisional porphyry ore formation in the Tethyan domain

Hongda Hao,Jung-Woo Park 대한지질학회 2022 대한지질학회 학술대회 Vol.2022 No.10

Effect of Molybdate Conversion Coating of Magnesium Alloy Reinforced by Micro-arc Oxidation

Hongda Zhu,Xuetian Li,Xiurong Guan,Zhongcai Shao 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

In order to enhance the corrosion resistance of molybdate conversion coating, the molybdate coating is subjected to micro-arcoxidation treatment in electrolyte with Na2SiO3as a main salt. The electrochemical behavior and corrosion weight loss ofdifferent coating were studied. The surface morphology, element composition, roughness and phase composition of differentcoatings were analyzed by SEM, EDS, laser confocal microscopy and XRD, the growth process of different micro-arcoxidation coatings was explored. The results shows that the arcing voltage of the molybdate coating enhanced by micro-arcoxidation is significantly reduced, the corrosion potential is shifted to the right, and the corrosion weightlessloss of thecoating is the lowest, compared with the molybdate coating and the micro-arc oxidation coating. Micro-arc oxidation on thesurface of the molybdate coating is beneficial to the formation of MgAl2O4and the production of new phase is MoSi2,whichcan better improve the corrosion resistance of the molybdate coating. The micro-arc oxide coating does not form a ceramicfilm with a pore structure at the moment of arcing. As the micro-arc oxidation time prolongs, the ceramic film is graduallyformed. When the time reaches 60 s, the ceramic film is completely formed.

Proliferated Leydig Cells for Engineered Testis-like Tissue Regeneration with Testosterone-Secreting Ability

Hongda Bi,Xiaoyun Wang,Wei Liu,Yilin Cao,Guangdong Zhou,Xin Xing 한국조직공학과 재생의학회 2014 조직공학과 재생의학 Vol.11 No.5

Tissue engineering approach provides a hopeful strategy for reconstructing testis testosterone-secreting functions. However, limited source and low proliferative activity in vitro of Leydig cells (LCs, the main testosteroneproducing cells) makes testis-like tissue regeneration difficult to be achieved. This study explored the feasibility of in vitro expanding LCs and their potential application in testis-like tissue regeneration. LC lineage cells were isolated from Sprague-Dawley (SD) rats by differential adhesion method and cell composition was identified by expressions of 3β-HSD, LHR, LIFR, and c-kit. A modified expansion medium (EM) system was used to test the feasibility of in vitro expanding LC lineage. The results showed that the attached cells reached a high purification of LC lineage (>90%, indicated by positive expression of 3β-HSD) and that EM significantly enhanced proliferation of LC lineage compared to regular medium, which was testified to be related to the presence of stem LCs that was implied by positive expressions of LIFR and c-kit as well as the transition of 3β-HSD expression from negative to positive in partial cells. Importantly, the proliferated LCs showed relatively sustained testosterone-secreting ability in vitro and these cells combined with biodegradable scaffolds successfully regenerated testis-like tissue with sustained testosteronesecreting function in vivo, which was supported by the enhanced serum testosterone level in castrated rats. All these results indicated that the differential adhesion method could efficiently isolate and purify LC lineage and that EM system could efficiently promote proliferation and functional maintenance of LC lineage, providing a good cell source for testes-like tissue regeneration. Tissue engineering approach provides a hopeful strategy for reconstructing testis testosterone-secreting functions. However, limited source and low proliferative activity in vitro of Leydig cells (LCs, the main testosteroneproducing cells) makes testis-like tissue regeneration difficult to be achieved. This study explored the feasibility of in vitro expanding LCs and their potential application in testis-like tissue regeneration. LC lineage cells were isolated from Sprague-Dawley (SD) rats by differential adhesion method and cell composition was identified by expressions of 3β-HSD, LHR, LIFR, and c-kit. A modified expansion medium (EM) system was used to test the feasibility of in vitro expanding LC lineage. The results showed that the attached cells reached a high purification of LC lineage (>90%, indicated by positive expression of 3β-HSD) and that EM significantly enhanced proliferation of LC lineage compared to regular medium, which was testified to be related to the presence of stem LCs that was implied by positive expressions of LIFR and c-kit as well as the transition of 3β-HSD expression from negative to positive in partial cells. Importantly, the proliferated LCs showed relatively sustained testosterone-secreting ability in vitro and thesecells combined with biodegradable scaffolds successfully regenerated testis-like tissue with sustained testosteronesecreting function in vivo, which was supported by the enhanced serum testosterone level in castrated rats. All these results indicated that the differential adhesion method could efficiently isolate and purify LC lineage and that EM system could efficiently promote proliferation and functional maintenance of LC lineage, providing a good cell source for testes-like tissue regeneration.

Visibility Measurement in an Atmospheric Environment Simulation Chamber

Hongda Ta,Zibo Zhuang,Lihui Jiang,Dongsong Sun 한국광학회 2017 Current Optics and Photonics Vol.1 No.3

Obtaining accurate visibility measurements is a common atmospheric optical problem, and of vitalsignificance to civil aviation. To effectively evaluate and improve the accuracy of visibility measurements,an outdoor atmospheric simulation chamber with dimensions of 1.8×1.6×55.7 m3was constructed. Thesimulation chamber could provide a relatively homogeneous haze environment, in which the visibility variedfrom 10 km to 0.2 km over 5 hours. A baseline-changing visibility measurement system was constructedin the chamber. A mobile platform (receiver) was moved from 5 m to 45 m, stopping every 5 m, tomeasure and record the transmittance. The total least-squares method was used to fit the extinctioncoefficient. During the experiment conducted in the chamber, the unit weight variance was as low as1.33×10-4under high-visibility conditions, and the coefficient of determination (R2) was as high as 0.99under low-visibility conditions, indicating high stability and accuracy of the system used to measure theextinction coefficients and strong consistency between repeated measurements. A Grimm portable aerosolspectrometer (PAS) was used to record the aerosol distribution, and then Mie theory was used to calculatethe extinction coefficients. The theoretical results were found to be consistent with the measurements andexhibited a positive correlation, although they were higher than the measured values.

CSI Index Reconstitutions: A Quasi-Natural Experiment in China

Hongda Li,Srinivasan Selvam 한국증권학회 2021 Asia-Pacific Journal of Financial Studies Vol.50 No.2

We investigate whether the China Securities Index (CSI) reconstitutions are suitable as a quasi-natural experiment to investigate the influence of institutional ownership. Using both actual and predicted CSI 300 and 500 index constituents, we document a sharp discontinuity in institutional ownership, especially of domestic mutual funds around index thresholds, overcoming a key concern of the Russell reconstitution approach. Using inclusion in the CSI 500 index as an instrument, we find that higher institutional ownership increases dividend payouts, improves firm performance, and improves the firms’ information environment. These findings inform us of the salience of domestic institutions in emerging markets.

수소 이온 교환막 적용을 위한 나피온-폴리불화비닐리덴플로라이드 블렌드의 결정 구조 제어

서홍대(Hongdae Seo),배인성(Insung Bae) 한국고분자학회 2020 폴리머 Vol.44 No.4

전해질 고분자의 효과적인 수소이온 전달을 위해 대표적인 불소계 전해질 고분자 Nafion과 반결정성 강유전 고분자 polyvinylidene fluoride(PVDF)를 혼합하여 블렌드 전해질 막을 제조하였다. Nafion과 PVDF 분자 사이의 수소결합을 통하여 블렌드 막의 친수성 수소 이온 전달 채널을 더욱 발달시킴과 동시에 PVDF가 가지는 상 변화 현상을 활용하여, α 및 γ상 각각 경우에 대해 블렌드 막이 가지는 나노 구조와 막 물성 및 수소 이온 전도도의 상관관계를 파악하였다. 전해질 고분자의 나노 구조는 각각 atomic force microscopy과 small angle X-ray scattering를 통해 확인하였다. 최종적으로, Nafion-PVDF가 9 :1의 혼합비율을 가지는 경우, PVDF가 γ상을 형성하였을 때, 증가된 이온전도도와 습윤팽창에 대한 안정성을 갖는 것을 확인하였다. We present a controlled nanostructure of a proton conducting membrane, Nafion, by introducing a blend with a ferroelectric semi-crystalline polymer, polyvinylidene fluoride (PVDF). Phase transition between α and γ phases of PVDF attributes the molecular structure of the blend membranes and their hydrophilic ionic channels by a strong hydrogen bonding between two polymers. The nanostructure of the membrane was investigated by atomic force microscopy and small angle X-ray scattering. Consequently, the controlled nanostructure of the blend membrane with a blending ratio of 9:1 for Nafion: γ-PVDF allows enhanced proton conduction and increased physical stability for water swelling.

自動車 3社의 消費者行動에 관한 硏究 : 스텐톤 모델을 중심으로 A Structural Approach to the Stanton Model

金弘大 新羅大學校 1990 論文集 Vol.30 No.-

This paper aims to explain consumer behavior for the three company:HYUNDAI, DAEWOO and KIA. This paper has dicussed consumer behavior based on a structural approach to the Stanton model. It has summarized theoretical support for the model and has evaluated its application in a marketing decision environemnt. The results of this research suggest that this model is conceptually sound and managerially useful. Application of the model provides detailed data for determining market position and designing strategy to modify that position. We would want to understand cultural, social, personal, and psychological factors that operate in her life. Cultural factors include the culture from whcih she comes, her subculture identifications and her social class. Social factors include the influence of other people in her life, particularly her reference groups, family, and roles and statuses. Personal characteristics life style, and personality. Finally, psychological characteristics include her motivation, perceptions, attitudes and beliefs, and learning. The company's task is to work hard to get its brand included in the buyer's awareness set and to remain in the successive lonsideration and choice set. The marketer must research the other brands that are likely to be include and the criteria used by the buyer as she moves to successively smaller sets in making her decision. We believe that a variety of theoretical and analytic models in the marketing literature can and do help managers make better decisions. The informed manager selects those models and measurements that are right for the specific circumstances of the managerial problem being examined.