• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.355-355
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• 2016

There has been an explosive development of nanocrystal (NC) synthesis and application due to their composition-dependent specific properties. Despite the composition, shape, and size of NCs foremost determine their physicochemical properties, the surface state and molecule conjugation also drastically change their characteristics. To make practical use of NCs, it is a prerequisite to understand the NC surface state and the degree to which they have been modified because the reaction occurs on the interface between the NCs and the surrounding medium. We report in here an analysis method to identify conjugated ligands and their binding states on semiconductor nanocrystals based on their molecular information. Surface science techniques, such as time-of-flight secondary-ion mass spectrometry (ToF-SIMS) and FT-IR spectroscopy, are adopted based on the micro-aggregated sampling method. Typical trioctylphosphine oxide-based synthesis methods of CdSe/ZnS quantum dots (QDs) have been criticized because of the peculiar effects of impurities on the synthesis processes. Since the ToF-SIMS technique provides molecular composition evidence on the existence of certain ligands, we were able to clearly identify the n-octylphosphonic acid (OPA) as a surface ligand on CdSe/ZnS QDs. Furthermore, the complementary use of the ToF-SIMS technique with the FT-IR technique could reveals the OPA ligands' binding state as bidentate complexes.

• 대한인간공학회지
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• 제35권1호
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• pp.39-52
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• 2016

Objective: This paper investigates gait changes according to different heel heights and speeds, and the interaction between the effects of the heel height and the speed during walking on stride parameters and joint angles. Furthermore, the relationship among heel height, speed and gait variables is investigated using linear regression. Background: Gait changes by heel height or speed have been studied respectively, but has not been reported whether there is an interaction effect between heel height and speed. It would be necessary to understand how gait changes when a person wears heels in different heights at various speeds, for example, high-heeled walking at fast speed, since it may cause unusual gait patterns and musculoskeletal disorders. Method: Ten females were asked to walk at five fixed cadences (94, 106, 118, 130 and 142 steps/min.) wearing three shoes with different heel heights (1, 5.4 and 9.8cm). Nineteen gait variables were analyzed for stride parameters and joint angles using two-way repeated measure analysis of variance and regression analysis. Results: Both heel height and speed affect movement of ankle, knee, spine and elbow joint, as well as stride length and Double/Single support time ratio. However, there is no significant interaction effect between heel height and speed. The regression result shows linear relationships of gait variables with heel height and speed. Conclusion: Heel height and speed independently affect stride parameters and joint angles without a significant interaction, so the gait variables are linearly amplified or diminished by the two factors. Application: Walking in high heels at fast speed should be careful for musculoskeletal disorders, since the amplified movement of knee and spine joint can lead to increased moment. Also, the result might give insight for animators or engineers to generate walking motion with high heels at various speeds.

• Journal of Radiation Protection and Research
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• 제42권1호
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• pp.48-55
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• 2017

Background: Simultaneous detection of neutrons and gamma rays have become much more practicable, by taking advantage of good gamma-ray discrimination properties using pulse shape discrimination (PSD) technique. Recently, we introduced a commercial CLYC system in Korea, and performed an initial characterization and simulation studies for the CLYC detector system to provide references for the future implementation of the dual-mode scintillator system in various studies and applications. Materials and Methods: We evaluated a CLYC detector with 95% $^6Li$ enrichment using various gamma-ray sources and a $^{252}Cf$ neutron source, with validation of our Monte Carlo simulation results via measurement experiments. Absolute full-energy peak efficiency values were calculated for gamma-ray sources and neutron source using MCNP6 and compared with measurement experiments of the calibration sources. In addition, behavioral characteristics of neutrons were validated by comparing simulations and experiments on neutron moderation with various polyethylene (PE) moderator thicknesses. Results and Discussion: Both results showed good agreements in overall characteristics of the gamma and neutron detection efficiencies, with consistent ~20% discrepancy. Furthermore, moderation of neutrons emitted from $^{252}Cf$ showed similarities between the simulation and the experiment, in terms of their relative ratios depending on the thickness of the PE moderator. Conclusion: A CLYC detector system was characterized for its energy resolution and detection efficiency, and Monte Carlo simulations on the detector system was validated experimentally. Validation of the simulation results in overall trend of the CLYC detector behavior will provide the fundamental basis and validity of follow-up Monte Carlo simulation studies for the development of our dual-particle imager using a rotational modulation collimator.

• 한국광학회지
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• 제25권2호
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• pp.95-101
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• 2014

표면 플라즈몬 공명 (SPR) 센서에서 금속 전극에 전압을 걸었을 경우, 표면에 여기 되는 전기장에 의해 전하가 쌓이게 된다. 이는 금속 표면의 광학적 성질과 표면 플라즈몬 공명 각도의 변화를 야기시킨다. 본 논문에서는 그에 대한 검증을 위해 다양한 산도 조건의 수용액 하에서 금속에 전압을 걸었을 때의SPR 각도 변화를 측정하였고, 누적 전하량과 공명 각도에 대한 의존성을 그렸을 때 수용액의 산도에 관계없이 일치함을 확인 하였다. 이 관계를 설명하는 기존의 공간전하층(SCL) 모델과 비교해보고 실험결과와 어긋나는 부분과도 잘 맞는 수정된 SCL 모델을 제시하였다. 이 결과는 표면 플라즈몬 공명 센서의 응용과 금속박막의 광학적 성질에 대한 연구에 기여할 거라 기대된다.

• 융합정보논문지
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• 제11권12호
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• pp.168-175
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• 2021

본 연구에서는 인공지능 교육을 활용하여 생물 교육의 파충류와 양서류를 분류에 대한 이해를 높이고, AI(Artificial Intelligence) 역량을 증대할 수 있도록 탈학문적(Transdisciplinary) 융합 교육 프로그램을 개발하였다. 중심 내용으로는 생물교육에서 오랫동안 다루어진 주제인 파충류와 양서류의 분류를 의사결정 트리 및 ML4K(Machine Learnig for Kids)를 활용하여 해결하는 것으로, 총 3차시 분량으로 설계하였다. 개발된 교육 프로그램에 대하여 전문가 검토를 실시하였고, 그 결과 I-CVI 값이 .88~1.00을 나타내어 내용 타당도를 확보하였다. 이 교육 프로그램은 학습자들에게 정보 교육의 인공지능에 관한 학습 내용과 생물 교육의 척추 동물의 분류에 관한 학습 내용에 대해 동시에 학습할 수 있다는 강점이 있다. 또한, 인공지능 활용 부분에서는 인지 부하를 최소로 하도록 구성되어 있기 때문에 모든 교사들이 쉽게 활용할 수 있다는 점이 특징이다.

• 대한방사성의약품학회지
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• 제4권2호
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• pp.73-79
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• 2018

In our previous study, tricarbonyl $^{99m}Tc$-labeled TSPO-binding ligand, named $^{99m}Tc$-CB256, having positively charge (+1) was investigated but did not show promising results in in vivo environment despite of a nanomolar binding affinity for TSPO. Because the overall positively charge of $^{99m}Tc$-CB256 would likely interrupt its target protein uptake, we herein designed the neutral tricarbonyl-$^{99m}Tc$ labeled TSPO-binding ligand ($^{99m}Tc$-CB257, 1). $^{99m}Tc$-CB257 was prepared by the facile incorporation of the $[^{99m}Tc(CO)_3]^+$ into a N-(hydroxycarbonylmethyl)-2-picoly moiety in CB257. The radiochemical yield of $^{99m}Tc$-CB257 after HPLC purification was $54.1{\pm}2.4%$ (decay corrected, n = 3). The authentic Re-CB257 (2) was synthesized by using $(NEt_4)_2[Re(CO)_3Br_3]$ in 69.0% yield. The binding affinity of 2 for TSPO was measured in leukocyte and showed approximately 280 times higher than that observed for the positively charged (+1) ligand, Re-CB256 ($K_i=0.57{\pm}0.06nM$ versus $159.3{\pm}8.7nM$, respectively). Our results indicated that 1 can be considered potentially as a new SPECT radiotracer for TSPO-rich cancer and provides the foundation for further in vivo evaluation related with abnormal TSPO-overexpression environments.

• 영미문화
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• 제18권2호
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• pp.27-50
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• 2018

Old age is often compared as climbing mountains which requires walking out of breath, yet with wider vision. And it is also likened to the estuary where the river flows slowly and broadly into the open sea. Socially, old age has been regarded as a symbol of wisdom and reflection, and elderly people often take the role of sage who leads the community. On the other hand, the dementia, gray hair and wrinkles of old age were sometimes perceived as the decline of intellect and vitality. Especially, in the digital age in which technology makes people more sensitive to physical artificiality, the evaluation of the old age becomes more complex and obscure. In other words, some elderly people can not escape from Confucious convention of the elders first, which causes the denouncement by younger generations. On the other hand, some elderly people are becoming more adaptable to the trend of young people, emerging as the new elderly people. The anti-aging movement, early adaptation of IT, bioengineering regimen also strong for the advanced age. However, as the new elderly people are active in many fields of society, they also face intergenerational conflicts in some areas where remains the overlap between young people and them due to the limited openings in economy and culture. This study is a transdisciplinary research which can be called old age humanities. First of all, this paper looks at the aspects of lifestyles and intergeneration conflicts in old age in four Korean and Western literary works about the old people, and also searches how to improve the quality of the later life of old people, Overall, this paper aims to explore the way the old people can achieve the full life with the help of intergenerational dependency through building aging humanities and new communities for old people.

• 한국식품영양학회지
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• 제35권6호
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• pp.399-410
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• 2022

To enhance the bioavailability and bioactivities of mixed herbal medicines (RW), they were fermented with lactic-acid bacteria isolated from kimchi into postbiotics (FRW). Then, from the results of the 16s rRNA sequencing analysis, lactic acid bacteria isolated from kimchi were identified to be of two species, namely Lactobacillus sakei and Leuconostoc mesenteroides. The FRW prepared from the RW were extracted using hot water (HW) and 70% EtOH (EtOH) for comparison of their macrophage-stimulating activities. Based on a comparison of the activities of the FRW extracts, nitric oxide (NO) production of HW was significantly higher than that in EtOH. An analysis of the chemical properties of the extracts showed that HW had higher contents of neutral sugar and uronic acid than EtOH as well as contained a large amount of glucose. In addition, crude polysaccharide (CP) was prepared to enhance the macrophage-stimulating activity. The FRW-CP not only secreted immunostimulatory mediators but also increased the expression of immunostimulatory genes (iNOS, TNF-α, MCP-1, and IL-6). The fractionated FRW-CP contained about 90% neutral sugars, and these sugars were mainly composed of glucose, galacturonic acid, and arabinose. Thus, FRW prepared by fermentation of RW with kimchi lactic acid bacteria were found to be immunostimulatory modulators.

• 한국멀티미디어학회논문지
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• 제21권8호
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• pp.1002-1020
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• 2018

Virtual reality (VR) technologies, which have been improved of late, offer experiences closer to reality than before. While VR technologies are expected to be an effective medium if used in learning content that cannot be offered in real life, distraction factors in VR technologies may prevent the users' presence and flow, making these technologies ineffective. Therefore, this study, through experiment and observation, analyzed the effect of distraction factors on the user's experience perception and learning effect when using HMD-based immersive VR. Experimental results revealed that the distraction factors were shown to have a negative, albeit not generally significant (except for tactile interactivity), effect on vividness, tactile interactivity, locomotive interactivity, presence, and flow. Ultimately, they were shown to have a negative effect on learning.

• 한국컴퓨터정보학회논문지
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• 제22권3호
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• pp.27-34
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• 2017

We propose a cascade lane detector that uses biased discriminant analysis (BDA) to work effectively even when there are various external factors on the road. The proposed cascade detector was designed with an existing lane detector and the detection module using BDA. By placing the BDA module in the latter stage of the cascade detector, the erroneously detected results by the existing detector due to sunlight or road fraction were filtered out at the final lane detection results. Experimental results on road images taken under various environmental conditions showed that the proposed method gave more robust lane detection results than conventional methods alone.