• Korean Journal of Culture and Social Issue
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• v.11 no.spc
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• pp.85-95
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• 2005

The present article explored the studies on the relational mechanisms between trust and health in terms of psychosomatic medicine or integrative medicine. For this, the research findings of the Quantum physics, psychosomatic medicine, and traditional eastern healing methods on the mind-body problem and then a practical guide to greater physical and mental well-being is presented. In the first section of the Quantum mechanical human body, the body has a mind of its own, the mechanism and cause of disease, the body as objective experienced conscious, and the effects of consciousness and information on the body are includes. The second section is psychosomatic medicine. In this, the thought changing brain, placebo, the power of expectancy, achieving health by active endeavor, psychoneuroimmunology, and the several therapies are included. Finally, Dr. Benson and Proctor's practical guide to well-being in presented. It is emphasized that the four trusts (trust in oneself, one's doctor, one's treatment, and one's spiritual trust) are crucial to recovery from serious illness and to achieve better health.

• Bulletin of the Korean Chemical Society
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• v.23 no.2
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• pp.281-285
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• 2002

The photophysical properties and the singlet oxygen generation efficiencies of meso-tetraphenyl-trithiasapphyrin $(S_3TPS)$ and meso-tetmkis(p-methoxy phenyl)-trithiasapphy rin ((p-MeO)-$S_3TPS$) have been investigated, utilizing steady-state and time-resolved spectroscopic methods to elucidate the possibility of their use as photosensitizers for photodynamic therapy (PDT). The observed photophysical properties were compared with those of other porphyrin-like photosensitizers in geometrical and electronic structural aspects, such as extended ${\pi}$ conjugation, structural distortion, and internal heavy atoms. The steady-state electronic absorption and fluorescence spectra were both red-shifted due to the extended ${\pi}$-conjugation. The fluorescence quantum yields were measured as very small. Even though intersystem crossing rates were expected to increase due to the increment of spin orbital coupling, the triplet quantum yields were measured as less than 0.15. Such characteristics can be ascribed to the more enhanced internal conversion rates compared with the intersystem crossing rates. Furthermore, the triplet state lifetimes were shortened to -1.0 ${\mu}s$ as expected. Therefore, the singlet oxygen quantum yields were estimated to be near zero due to the fast triplet state decay rates and the inefficient energy transfer to the oxygen molecule as well as the low triplet quantum yields. The low efficiencies of energy transfer to the oxygen molecule can be attributed to the lower oxidation potential and/or the energetically low lying triplet state. Such photophysical factors should be carefully evaluated as potential photosensitizers that have extended ${\pi}$-conjugation and heavy core atoms synthesized for red-shifted absorption and high triplet state quantum yields.

• Journal of Power Electronics
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• v.16 no.4
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• pp.1268-1276
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• 2016

A triode for alternating current (TRIAC) dimming light emitting diode (LED) driver, which adopts a variable switched capacitor for LED dimming and LED power regulation, is proposed in this paper. The proposed LED driver is power efficient, reliable, and long lasting because of the TRIAC switch that serves as its main switch. Similar to previous TRIAC dimmers for lamps, turn-on timing of a TRIAC switch can be controlled by a volume resistor, which modulates the equivalent capacitance of the proposed variable switched capacitor. Thus, LED power regulation against source voltage variation and LED dimming control can be achieved by the proposed LED driver while meeting the global standards for power factor (PF) and total harmonic distortion (THD). The long life and high power efficiency of the proposed LED driver make it appropriate for industrial lighting applications, such as those for streets, factories, parking garages, and emergency stairs. The detailed analysis of the proposed LED driver and its design procedure are presented in this paper. A prototype of 80 W was fabricated and verified by experiments, which showed that the efficiency, PF, and THD at V_s = 220 V are 93.8%, 0.95, and 22.5%, respectively; 65 W of LED dimming control was achieved with the volume resistor, and the LED power variation was well mitigated below 3.75% for 190 V < V_s < 250 V.

• Convergence Security Journal
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• v.19 no.2
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• pp.11-19
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• 2019

The blockchain is a technique for managing transaction data in distributed computing manner without the involvement of central trust authority. The blockchain has been used in various area such as manufacturing, culture, and public as well as finance because of its advantage of the security, efficiency and applicability. In the blockchain, it was considered safe against 51% attack because the adversary could not have more than 50% hash power. However, there have been cases caused by large-scale computing attacks such as 51% and selfish mining attack, and the frequency of these attacks is increasing. In addition, since the development of quantum computers can hold exponentially more information than their classical computer, it faces a new type of threat using quantum algorithms. In this paper, we perform the security analysis of blockchain attacks composing the large computing capabilities including quantum computing attacks. Finally, we suggest the technologies and future direction of the blockchain development in order to be safe against large-scale computing attacks.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.8 no.1
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• pp.9-15
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• 2022

Anti-cancer and therapeutic effects using therapeutic radioisotopes have been demonstrated by various studies, and it is well-known that therapeutic radioisotopes are useful in cancer treatment. Recently, one of the therapeutic radioisotopes, scandium is emerging as a radioisotope applicable to PET imaging (⁴³Sc, ⁴⁴Sc) and therapy (⁴⁷Sc) in cancer theranostic approach. However, ⁴⁷Sc has little known radiobiological and therapeutic efficacy compared to other therapeutic radioisotopes. Here, we investigated the quality and therapeutic efficacy of ⁴⁷Sc radioisotope produced by our production/isolation technology at the research reactor 'HANARO' in KAERI (Korea Atomic Energy Research Institute). We showed that the therapeutic efficacy of ⁴⁷Sc, produced by our production/isolation technology, effectively suppressed epidermal growth factor receptor (EGFR)-targeted non-small cell lung cancer (NSCLC) cells. Consequently, these results suggest that the high quality of the produced ⁴⁷Sc by our production/isolation technology enables the development of therapeutic strategies for cancer treatment and radiopharmaceuticals using ⁴⁷Sc.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.07a
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• pp.334-337
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• 2002

The Quantum Hall Resistance(QHR) device which consists of GaAs/AlGaAs heterojunction structure is used for the realization of QHR Standard based on QHE. In order to characterize electrical contact resistances and dissipations of the device, it is slowly cooled down for eliminating thermal shock and unwanted noise. Then, the two properties are measured under 1.5 K and 5.15 T. Contact resistances are all within 1.2 Ω and longitudinal resistivities are all within 1 mΩ up to DC 90${\mu}$A. The results mean the device is operated well to realize the QHR Standard. To confirm it, the QHR Standard having the device is compared using a direct current comparator bridge with a 1 Ω resistance standard which the calibrated value is known from QHR standards maintained by other countries. The difference between them is agreed well within measurement uncertainty. It is thus considered that the properties of the device is estimated well and has good performance.

• Journal of the Korean Institute of Telematics and Electronics D
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• v.35D no.10
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• pp.91-97
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• 1998

The modulation performance of 10 Gbps electro-absorption InGaAsP/InGaAsP strain compensated MQW (Multiple Quantum Well) modulator module depends on the modulator as well as the package parasitics. The high frequency package parasitics resulting from various structural discontinuities, limit the modulation bandwidth and increase the chirp-parameter. Therefore, we propose the double bondwires embedded in dielectric materials to minimize the bondwire parasitics. Using the proposed structure with 50 $\Omega$ terminating resistor, the modulation bandwidth is greatly increased by 125 % than the bare chip and the chirp-parameter is also reduced. This technique can be used in optimizing the package of high speed external modulators.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.293-293
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• 2014

Over last decade InGaN alloy structures have become the one of the most promising materials among the numerous compound semiconductors for high efficiency light sources because of their direct band-gap and a wide spectral region (ultraviolet to infrared). The primary cause for the high quantum efficiency of the InGaN alloy in spite of high threading dislocation density caused by lattice misfit between GaN and sapphire substrate and severe built-in electric field of a few MV/cm due to the spontaneous and piezoelectric polarizations is generally known as the strong exciton localization trapped by lattice-parameter-scale In-N clusters in the random InGaN alloy. Nonetheless, violet-emitting (390 nm) conventional low-In-content InGaN/GaN multi-quantum wells (MQWs) show the degradation in internal quantum efficiency compared to blue-emitting (450 nm) MQWs owing higher In-content due to the less localization of carrier and the smaller band offset. We expected that an improvement of internal quantum efficiency in the violet region can be achieved by replacing the conventional low-In-content InGaN/GaN MQWs with ultra-thin, high-In-content (UTHI) InGaN/GaN MQWs because of better localization of carriers and smaller quantum-confined Stark effect (QCSE). We successfully obtain the UTHI InGaN/GaN MQWs grown via employing the GI technique by using the metal-organic chemical vapor deposition. In this work, 1 the optical and structural properties of the violet-light-emitting UTHI InGaN/GaN MQWs grown by employing the GI technique in comparison with conventional low-In-content InGaN/GaN MQWs were investigated. Stronger localization of carriers and smaller QCSE were observed in UTHI MQWs as a result of enlarged potential fluctuation and thinner QW thickness compared to those in conventional low-In-content MQWs. We hope that these strong carrier localization and reduced QCSE can turn the UTHI InGaN/GaN MQWs into an attractive candidate for high efficient violet emitter. Detailed structural and optical characteristics of UTHI InGaN/GaN MQWs compared to the conventional InGaN/GaN MQWs will be given.

• Journal of the Korea Convergence Society
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• v.8 no.5
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• pp.161-167
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• 2017

We have fabricated and characterized $32{\times}32$ photonic quantum ring (PQR) laser arrays uniformly operable with $0.98{\mu}A$ per ring at room temperature. The typical threshold current, threshold current density, and threshold voltage are 20 mA, $0.068A/cm^2$, and 1.38 V. The top surface emitting PQR array contains GaAs multiquantum well active regions and exhibits uniform characteristics for a chip of $1.65{\times}1.65mm^2$. The peak power wavelength is $858.8{\pm}0.35nm$, the relative intensity is $0.3{\pm}0.2$, and the linewidth is $0.2{\pm}0.07nm$. We also report the wavelength division multiplexing system experiment using angle-dependent blue shift characteristics of this laser array. This photonic quantum ring laser has angle-dependent multiple-wavelength radial emission characteristics over about 10 nm tuning range generated from array devices. The array exhibits a free space detection as far as 6 m with a function of the distance.

• Proceedings of the Korean Vacuum Society Conference
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• 2010.08a
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• pp.234-234
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• 2010

The PR transitions in asymmetric dot-in-double-quantum-well (DdWELL) photodetector is identified by bias-dependent spectral behaviors. Discrete n-i-n infrared photodetectors were fabricated on a 30-period asymmetric InAs-QD/[InGaAs/GaAs]/AlGaAs DdWELL wafer that was prepared by MBE technique. A 2.0-monolayer (ML) InAs QD ensemble was embedded in upper combined well of InGaAs/GaAs and each stack is separated by a 50-nm AlGaAs barrier. Each pixel has circular aperture of 300 um in diameter, and the mesa cell ($410{\times}410\;{\mu}m^2$) was defined by shallow etching. PR measurements were performed in the spectral range of $3{\sim}13\;{\mu}m$ (~ 100-400 meV) by using a Fourier-transform infrared (FTIR) spectrometer and a low-noise preamplifier. The asymmetric photodetector exhibits unique transition behaviors that near-/far-infrared (NIR/FIR) photoresponse (PR) bands are blue/red shifted by the electric field, contrasted to mid-infrared (MIR) with no dependence. In addition, the MIR-FIR dual-band spectra change into single-band feature by the polarity. A four-level energy band model is proposed for the transition scheme, and the field dependence of FIR bands numerically calculated by a simplified DdWELL structure is in good agreement with that of the PR spectra. The wavelength shift by the field strength and the spectral change by the polarity are discussed on the basis of four-level transition.