김하진 교수

We report scanning tunneling microscopy of semiconductor-semiconductor carbon nanotube junctions with different band gaps. Characteristic features of the wave functions at different energy levels, such as a localized defect state, are clearly exhibited in the atomically resolved scanning tunneling spectroscopy. The peaks of the Van Hove singularity on each side penetrate and decay into the opposite side across the junction over a distance of approximately 2 nm. These experimental features are ac

The present study aimed to compare the bone-regeneration capacity of porcine-derived xenografts to bovine-derived xenografts in the rat calvarial defect model. The observation of surface morphology and in vitro cell studies were conducted prior to the animal study. Defects with a diameter of 8 mm were created in calvaria of 20 rats. The rats were randomly treated with porcine-derived (Bone-XP group) or bovine-derived xenografts (Bio-Oss group) and sacrificed at 4 and 8 weeks after surgery. The n

The multi-stage effect has been revisited through growing carbon nanotube field emitters on single strand carbon fiber with a thickness of 11 µm. A prepared linear electron source exhibits a turn-on field as low as 0.4 V µm(-1) and an extremely high field enhancement factor of 19,300, when compared with those results from reference nanotube emitters grown on flat silicone wafer; 3.0 V µm(-1) and 2500, respectively. In addition, we introduce a novel method to grow nanotubes uniformly around the c

The local electronic structure of semiconducting single-wall carbon nanotubes was studied with scanning tunneling microscopy. We performed scanning tunneling spectroscopy measurement at selected locations on the center axis of carbon nanotubes, acquiring a map of the electronic density of states. Spatial oscillation was observed in the electronic density of states with the period of atomic lattice. Defect induced interface states were found at the junctions of the two semiconducting nanotubes, w

In this study, the concept of autoinhibition, a mechanism of protein activity regulation, was applied to the design and engineering of a β-lactamase zymogen. Using this zymogen, a sensitive protease assay method was developed in which activation of the zymogen by proteases produces an amplified absorbance signal. The approach reported here can be adapted for engineering of zymogens as biological sensors and components of synthetic signaling pathways.

Corporations have enormous influence on society. Progressive policymakers and scholars increasingly advocate for corporations to be required to consider those influences on society—a corporate social responsibility (CSR) mandate. The now‐predominant view is that merely allowing directors to consider society (a permissive regime) is ineffective. This article suggests that a CSR mandate could backfire by reducing the reputational rewards to pro‐social corporate acts. If stakeholders (customers, em

General physician, internal medicine, and family medicine are the fields providing comprehensive medical care in Korea. Clinics located in metropolitan area and capital city show lower comprehensiveness. The number of physicians is related to higher comprehensiveness of clinics.

이 연구는 국내외 정보학 분야 학회지 동향을 파악하기 위하여 1990년부터 2013년까지 국내 정보관리학회지와 국외 JASIST의 논문 제목과 초록을 대상으로 텍스트 마이닝 기법을 통한 명사, 명사구 동시출현 분석을 수행하였다. 전 기간을 5구간으로 나누고 전체적인 동향을 살펴보기 위해 고빈도 동시출현단어를 분석하였으며, 세부 주제를 파악하기 위해 상위 키워드와 동시에 출현하는 단어를 분석하였다. 마지막으로 과거와 다르게 새로운 키워드가 등장하는 2010년 이후 동향을 중점적으로 네트워크 분석을 수행하였다. 분석 결과 전반적으로 국내의 경우 정보관리학회지는 도서관, 정보 서비스, 정보 이용자, 정보 자료 조직 주제 분야가 많이 차지하고 있었고 JASIST는 정보 검색, 정보 이용자, 웹 관련 정보학, 계량 정보학 중심으로 연구가 진행되었다.

Biogas consists of methane and carbon dioxide, the main components, which are major greenhouse gases that affect global warming. As such, in order to convert greenhouse gas into renewable energy, which is a high-quality fuel, the biogas microwave reforming characteristics were studied and the results are as follows: In the main components of biogas, methane and carbon dioxide, the conversion efficiency of both methane and carbon dioxide increased as the amount of CO2 relatively increased. This i

Oxidized porous silicon (OPS) nanoparticles covalent-bonded with levofloxacin in hydrogel polymer are prepared and used to measure the efficiency for the controlled release drug delivery. Levofloxacin is covalently bonded to a Si-OH surface of OPS nanoparticles by catalytic condensation. The average size of these particles is about 100 nm. Since levofloxacin has a fluorescence property, the release of levofloxacin has been measured by fluorescence spectrometer. The quantity of levofloxacin relea