Search

Joint problems impair performance during exercise and daily activities and influence quality of life. The present study aimed to examine the effects of a combination of six non-essential amino acids (6AA) on joint conditions in an adult population. A total of 50 participants aged between 20 and 64 years with joint discomfort but no diagnosed joint disorder were randomly and blindly assigned to a control or 6AA group. The 6AA group took 12 g of the non-essential amino acid formulation orally (4 g three times a day) and the control group took equivalent doses of a placebo. Each group maintained the daily dose for 12 weeks. Primary outcome measures were evaluated with the visual analogue scale (VAS), the Japanese Knee Osteoarthritis Measure (JKOM), and the Japanese Orthopaedic Association score (JOA). These tests were taken before the experiment began at 4 weeks and 12 weeks after the intervention. The results of the VAS indicated that 6AA improved joint pain, discomfort, and stiffness both during a resting state and during normal activity. Participants’ scores on the JKOM and JOA also showed significant improvements in the group that had taken the 6AA supplement. These results demonstrate that 6AA improves symptoms of joint problems, such as pain, discomfort, stiffness, and difficulty in performing daily activities after 4 weeks of daily consumption.

There was no appropriate antireflection coating material for organic nonlinear optical (NLO) crystal used for terahertz wave generation; therefore, it was difficult to reduce Fresnel’s reflection loss of laser power used to excite the emitter crystal until we found that an amorphous polymer “Cytop” was applicable. Here, we demonstrate enhanced terahertz (THz) wave generation from an organic NLO crystal using a coating made from Cytop. With the Cytop coating, surface reflection losses of the excitation light were minimized, resulting in a significant improvement in THz wave generation over a wide frequency range.

2-(3-(4-Hydroxystyry1)-5,5-dimethylcyclohex-2-enylidene) malononitrile (OH1) is the only organic nonlinear optical (NLO) crystal that can be crystallized by physical vapour deposition (PVD) for terahertz (THz) wave generation. We report some optimizations of the growth temperature conditions of single-crystalline thin film by PVD. After transforming the setting temperature conditions from 90–120–180 °C to 90–145–180 °C, we observed that the temperature conditions influence the size of the OH1 single-crystalline thin film. Moreover, we found that, when the temperature gradient conditions were held at 90–135–180 °C during PVD for the growth of OH1 single-crystalline thin film, the single-crystalline thin films had longer b-axial extensions, which may be better-suited to nonlinear optics. The infrared transmission spectroscopy absorption peak positions of the OH1 single-crystalline thin film fabricated in this study were the same as those of bulk OH1 crystal. The crystallinity of the OH1 single-crystalline thin film was higher than that of bulk OH1 crystal, under all temperature conditions.

We demonstrate the visualization of an amplitude and phase distribution of a frequency-modulated continuous wave (FMCW) radar signal (318 MHz bandwidth) at 76.5 GHz. The system is based on an asynchronous technique using an integrated multichannel electro-optic probe in which neither a reference probe nor a cable plugged to the RF source is required. Near field of the FMCW electric field emitted from a horn antenna was measured and radiation pattern was characterized.

The 4-N, N-dimethylamino-4′-N'-methyl stilbazolium tosylate (DAST) crystal has a high figure of merit among nonlinear optical crystals [1]. In second-order nonlinear optical (NLO) processes using a DAST crystal, the $d_{111}$ process generally used is the process of generating a-axis polarized light from incident $a$ -axis polarized light. However, there has been very little investigation of other effective nonlinear processes utilizing other second-order NLO processes. In this study, we investigated generation of terahertz (Thz) waves via the $d_{133}$ process of the DAST crystal using the prism-coupled Cerenkov phase matching (PCC-PM) method [2], [3]. THz waves were generated efficiently using the $d_{133}$ process, and the magnitude of the nonlinear optical coefficient $d_{133}$ estimated from the THz intensity ratio was 34.1 pm/V. These results indicate that PCC-PM can be used to examine unevaluated $d$ -values of NLO crystals and estimate their values.

The higher the frequency, the more complex the scattering, diffraction, multiple reflection, and interference that occur in practical applications such as radar-installed vehicles and transmitter-installed mobile modules, etc. Near-field measurement in “real situations” is important for not only investigating the origin of unpredictable field distortions but also maximizing the system performance by optimal placement of antennas, modules, etc. Here, as an alternative to the previous vector-network-analyzer-based measurement, we propose a new asynchronous approach that visualizes the amplitude and phase distributions of electric near-fields three-dimensionally without placing a reference probe at a fixed point or plugging a cable to the RF source to be measured. We demonstrate the visualization of a frequency-modulated continuous wave (FMCW) signal (24 GHz ± 40 MHz, modulation cycle: 2.5 ms), and show that the measured radiation patterns of a standard horn antenna agree well with the simulation results. We also demonstrate a proof-of-concept experiment that imitates a realistic situation of a bumper installed vehicle to show how the bumper alters the radiation patterns of the FMCW radar signal. The technique is based on photonics and enables measuring in the microwave to millimeter-wave range.

A large unexamined second-order nonlinear optical (NLO) process is found in a 4-N,N-dimethylamino-4'-N'-methyl stilbazolium tosylate (DAST) crystal, which has a large figure of merit among NLO crystals. In second-order NLO processes using a DAST crystal, the

There are a number of advantages to terahertz (THz) waves by Cherenkov phase matching using a nonlinear optical (NLO) crystal; however, a thin crystal of micrometer-scale must be grown to satisfy t...

OH1 crystal is an organic nonlinear optical crystal with a large nonlinear optical constant. However, it has dispersion of refractive indices in the terahertz (THz) frequency. This limits the frequencies that satisfy the phase matching conditions for THz wave generation. In this study, we addressed the phase matching conditions for THz wave generation by combining an OH1 crystal with prism-coupled Cherenkov phase matching. We observed the generation of single-cycle THz pulses with a spectrum covering a frequency range of 3 THz. These results prove that combining prism-coupled Cherenkov phase matching with nonlinear optical crystals yields a THz wave generation method that is insusceptible to crystal dispersion.

The amorphous fluoropolymer CytopTM is a coating material for organic nonlinear optical crystals. As a coating material, it acts as both an antireflection coating and a protective layer for the crystal itself in advanced terahertz (THz) wave generation applications. In this study, we report on the optical parameter in THz frequency over a wide temperature ranges, and the optimization of THz wave generation from a Cytop-coated nonlinear optical crystal.

A large unexamined second-order nonlinear optical (NLO) process is found in a 4-N,N-dimethylamino-4’-N’-methyl stilbazolium tosylate (DAST) crystal, which has a large figure of merit among NLO crystals. In second-order NLO processes using a DAST crystal, the χ 111 ( 2 ) process of light excitation is commonly used, involving a-axis polarized light excitation with light generation of a-axis polarized light. However, there have been few studies of other second-order NLO susceptibility processes to date. In this Letter, terahertz (THz) wave generation via second-order NLO processes based on the χ 133 ( 2 ) second-order NLO susceptibility of the DAST crystal was investigated. By adjusting the polarization direction of the excitation light using a prism-coupled Cerenkov phase-matching method, efficient generation of THz waves was achieved using a process involving χ 133 ( 2 ) . The magnitude of the NLO constant χ 133 ( 2 ) estimated from the THz intensity ratio was 77.8 pm/V. These results indicate that prism-coupled Cherenkov phase matching can be used to identify undiscovered NLO processes for NLO crystals.

We achieved clean thin-film OH1 crystal growth by applying a physical vapor deposition (PVD) method with three different temperature gradients. We produced crystals appropriate for terahertz wave generation with the Cherenkov phase-matching method, as indicated by the crystal's larger b- axial extensions. According to measurements of the actual experimental temperatures inside the tubular furnace for PVD, the temperature for OH1 crystallization is required to be between 130 and 135°C.

This study deals with the effect of surface modifications induced from keV to MeV heavy ion beams on the initial reaction rate of a hydrogen storage alloy (AB5) in electrochemical process. The rare earth based alloys like this sample alloy are widely used as a negative electrode of Ni–MH (Nickel–Metal Hydride) battery. We aimed to improve the initial reaction rate of hydrogen absorption by effective induction of defects such as vacancies, dislocations, micro-cracks or by addition of atoms into the surface region of the metal alloys. Since defective layer near the surface can easily be oxidized, the conductive oxide layer is formed on the sample surface by O+ beams irradiation, and the conductive oxide layer might cause the improvement of initial reaction rate of hydriding. This paper demonstrates an effective surface treatment of heavy ion irradiation, which induces catalytic activities of rare earth oxides in the alloy surface.

We measured the solubility of bis-(2,2,6,6-tetramethyl-3,5-heptanedionato)copper(II) (Cu(tmhd) 2 ) in pure supercritical CO 2 (scCO 2 ) and binary mixtures of H 2 and scCO 2 at 40–100 °C and 11–20 MPa using spectrometric method. The solubility in scCO 2 was dependent on the density of CO 2 . The addition of H 2 to the scCO 2 had negative impact on the solubility, and the solubility was proportional to density of CO 2 with a constant mole fraction of H 2 . The equations proposed by Mendez-Santiago and Teja as well as Sauceau et al. were able to correlate the solubility in the pure CO 2 and binary systems. This approach provides a framework to determine the precursor concentration for supercritical fluid deposition (SCFD) of Cu. The precursor feed system for optimal Cu-SCFD was discussed. In addition, the same effect was found with the addition of O 2 and N 2 into scCO 2 , suggesting that further investigation into the solubility of SCFD precursors in these binary systems is warranted.

A mixed solid phase model using an equation of state based on hole-theory is developed for solubility calculation in supercritical CO2 considering the dissolution of CO2 into solid phase at high-pressure condition. Parameters in the equation of state were obtained from the molecular information calculated by a quantum calculation based on conductor-like screening model (COSMO). Twenty-three species of pharmaceutical compounds are mentioned as the target for the correlation or prediction of solubility in supercritical CO2. The predicted results of the solubility in supercritical CO2 by the mixed solid phase model are compared with those by the conventional pure solid phase model. It is found that the results for the pharmaceutical compounds with S, N, F, Cl and I atoms using the mixed solid phase model give the calculation performance better than those of the pure solid phase model. The mixed solid phase model was also applied for calculation of the CO2 solubility in solid phase.

Near-field mapping has proven to be a powerful technique for characterizing and diagnosing antennas in the microwave frequency range. However, conventional measurement methods based on a network analyzer cannot be applied to on-chip antenna devices extensively studied for future wireless communication in the millimeter wave (mm-wave) (30–300 GHz) and terahertz (THz) wave (0.1–10 THz) frequency regions. Here, we present a new asynchronous mapping technique to investigate the spatial distribution of not only the amplitude but also the phase of the electric field generated by free-running, self-oscillating generators including CMOS oscillators, Gunn oscillators, resonant tunneling diodes, and quantum cascaded lasers. Using a photonic-electronic hybrid measurement system, a wide frequency coverage, minimal invasiveness of the field to be measured, and phase distribution measurements with a theoretically-limited sensitivity are simultaneously achieved. As a proof-of-concept experiment, we demonstrate the mapping of a mm-wave (77 GHz) generated by a free-running Gunn oscillator and antenna characterization based on near-to-far field transformation.

We synthesized an ultrathin, nonlinear, optical OH1 crystal structure suitable for prism-coupled Cherenkov phase-matching terahertz (THz) wave generation. Physical vapor deposition was used to grow the crystal to a few micrometers thick. We observed THz wave generation from the thin-film crystal and characterized the crystal structure.

Pushing accuracy and reliability of radar systems to higher levels is a requirement to realize autonomous driving. To maximize its performance, the millimeter-wave radar has to be designed in consideration of its surroundings such as emblems, bumpers and so on, because the electric-field distortion will degrade the performance. We propose electro-optic (EO) measurement system to visualize amplitude and phase distribution of millimeter waves, aiming at the evaluation of the disturbance of car components with the radar module equipped inside a vehicle. Visualization of 76-GHz millimeter waves passing through plastic plates is presented to demonstrate our system's capability of diagnosing a local cause of the field disturbance.

We report on the production of theophylline nanoparticles by rapid expansion of supercritical solutions with a solid cosolvent (RESS-SC) using CO 2 with l -menthol or vanillin. The effects of particle collection conditions such as collection temperatures and spray distances on the theophylline nanoparticles produced were investigated in order to elucidate crystal growth mechanism of the present RESS-SC process. A liquid phase appeared at a pre-expansion section in the case of using l -menthol, and this suggests that it is unsuitable for a solid cosolvent in the present conditions. In the case of using vanillin, nano-sized particles of around 85 nm, which are about one-third as large as those produced by the conventional RESS technique, were obtained. Particle collection conditions have negligible effects on the particle sizes. This result suggests that crystal growth of theophylline particles crystallized in a collection vessel are blocked by crystallized vanillin particles those surrounds theophylline particles.

We have realized practical antireflection (AR) coatings for organic nonlinear optical crystals via dip coating of soft materials; specifically, the amorphous fluoropolymer Cytop. 4-N, N-dimethylamino-4′-N′-methyl-stilbazolium tosylate (DAST) crystals were coated with a Cytop solution; the coating thickness was controlled by the Cytop solution concentration. The Cytop coating did not show evidence of cracking or peeling after 200 days. The transmittance of AR-coated DAST crystals using a 5% Cytop solution was 90.9% at 1560 nm, an improvement of 17.8% compared to that before coating. High repeatability of the improvement was also confirmed. Moreover, the AR-coated DAST crystal was confirmed to have a stable transmittance over 720 minutes against the irradiation of a femtosecond laser with a power density of 3.6 GW/cm2. The ability to coat organic nonlinear optical crystals with an AR layer using soft materials is expected to have a wide range of optical applications.

Cytop is an amorphous fluororesin that has been attracting attention from researchers due to its potential application as an optical thin film coating for nonlinear optical (NLO) crystals in terahertz (THz) wave generation. In this study, we confirmed the suitability of Cytop as a coating material by measuring its optical parameters in the THz frequency band using THz time domain spectroscopy over a wide range of temperatures. Furthermore, as Cytop has a refractive index of about 1.35 in the light wave band, we also investigated its potential as an anti-reflection coating material for NLO crystals used as THz sources.

The surface oxide layer on nine different types of solution-annealed austenitic stainless steel (ASS) was evaluated by Secondary Ion Mass Spectrometry (SIMS). Tensile tests were conducted at 25 °C and −50 °C in hydrogen at 40 MPa and in air at atmospheric pressure. Relative reduction of area (RRA) was calculated accordingly. Additionally the martensite transformation curves were measured in air at −50 °C to evaluate the probability of the formation of α′ martensite nuclei. A linear relationship between RRA and the calculated probability of the nucleation of α′ martensite nuclei was found on samples represented by the following three oxides types; (a) thick oxide, (b) decaying sub-surface oxide and (c) thin surface oxides. However, type (d) with high constant oxide level down to 60 nm depth does not follow the trend. The observed variation of the oxide layer is linked to the variability of tensile test results.

Widely tunable terahertz (THz) waves were successfully generated from 0.5 to 10 THz via difference frequency generation (DFG) in a configurationally locked polyene 2-[3-(4-hydroxystyryl)-5,5-dimethylcyclohex-2-enylidene] malononitrile (OH1) crystal. Potassium titanium oxide phosphate optical parametric oscillator pumped by nanosecond Q-switched Nd:YAG laser was used to generate two waves, which were then used to irradiate OH1 crystal. The maximum energy of the generated THz wave was about 461 pJ/pulse. We investigated the dependency of generated THz energy to the excitation pump power density and OH1 crystal thickness. In addition, we compared the THz energy generated by OH1 crystal to 4-N,N-dimethylamino-4′-N′-methyl-4-stilbazolium tosylate (DAST) crystal using DFG, and we achieved 560 times higher energy using OH1 crystal than DAST crystal at around 1.1 THz.

Using a combination of Cherenkov phase matching method and nonlinear waveguide crystals, we achieved effective THz wave generation. The THz wave generated from LiNbO 3 ridge waveguide has over 1000 times stronger than that of conventional photoconductive antenna, broadband spectrum from 0.1 THz to 7 THz and over dynamic range 80 dB. Furthermore, we generated THz wave using other nonlinear optical crystals as DAST and OH1. Although DAST crystal has strong absorption at 1.1 THz, we succeeded to generated broadband THz wave without the strong absorption.

We show photonics-based field visualization technique which enables us to map the spatial distribution of the amplitude and phase of the millimeter and terahertz waves generated by the self-oscillating free-running sources. The frequency of the electromagnetic wave to be measured is down-converted to an IF signal by a non-polarimetric electrooptic (EO) detection technique. The frequency fluctuation of the IF signal due to that of the RF signal is cancelled out using a second IF signal, which is detected by a reference EO probe. We show the amplitude and phase visualization of the millimeter-wave (77.7 GHz) generated by a Gunn diode oscillator and emitted from a horn antenna.

蛋白質結晶構造解析用の新型中性子回折装置である茨城県生命物質構造解析装置(iBIX)が大強度陽子加速器施設(J-PARC)の次世代中性子源に建設され，2008年12月から本格運転を開始した。2009年度には，14台の検出器，データ処理ソフトウェアの基本的な部分，20Kまでの低温吹付装置が利用可能となり，有機物標準結晶の測定及び構造解析に成功した。2009年12月からの120kW加速器運転より，産業界ユーザーの試料を含む複数の無機，有機化合物そして蛋白質結晶の構造解析用中性子測定がなされ，そのうちいくつかは水素や水和水の位置がわかる程度まで構造解析が進んでいる。

In nonlinear optical (NLO) crystals, the selection of pump light wavelengths for the generation of terahertz (THz) waves is limited due to problems associated with coherence length, refractive index, and absorption by the crystal. Relaxation of this limitation would open up potential light sources for THz generation. One such solution, Cherenkov phase matching, removes the coherence length constraint. In this study, we attempted to generate THz waves from an NLO crystal using femtosecond pulses of various wavelengths. Specifically, 805-nm and 1560-nm femtosecond pulses were used to pump a prism-coupled LiNbO3 crystal. Broadband THz-wave generation and a THz-wave output proportional to the square of the pump light intensity were observed at both wavelengths. The generation of THz waves by prism-coupled Cherenkov phase matching was not limited by the wavelength of the pump light. Moreover, THz-wave generation at even greater intensities may be possible by optimizing the pump source and coupling to an NLO crystal.

We propose a new asynchronous measurement system to visualize the amplitude and phase distribution of a frequency-modulated electromagnetic wave. The system consists of three parts: a nonpolarimetric electro-optic frequency down-conversion part, a phase-noise-canceling part, and a frequency-tracking part. The photonic local oscillator signal generated by electro-optic phase modulation is controlled to track the frequency of the radio frequency (RF) signal to significantly enhance the measurable RF bandwidth. We demonstrate amplitude and phase measurement of a quasi-millimeter-wave frequency-modulated continuous-wave signal (24 GHz ± 80 MHz with a 2.5 ms period) as a proof-of-concept experiment.

The reactivity of H2 gas with the In and Sn surfaces was quantitatively measured by a volumetric method at pressures ranging from 10−7 to 10−2 Pa at 298 K. Significant enhancement of H2 reactivity was observed when O2 or H2O preadsorbed on the surface of In and Sn before H2 exposure. The formation of the oxygen deficient SnO2−x and In2O3−z in the surface layers is proposed as a reason for such a facilitating the H2 dissociation and resulting in the enhancement of the H2 reactivity at 298 K.

The pressure p –temperature T projections of solid–liquid–gas (S–L–G) three-phase coexistence lines for the carbon dioxide + tetradecanoic acid (C 14 H 28 O 2 ) system, the carbon dioxide + hexadecanoic acid (C 16 H 32 O 2 ) system, and the carbon dioxide + 1-hexadecanol (C 16 H 34 O) were measured by the first melting point method in which the initial appearance of the liquid phase was observed. The profiles of the p – T projections of the S–L–G lines for the carbon dioxide + acid systems are similar to each other, the S–L–G equilibria for the carbon dioxide + acid systems are, however, different from that for the carbon dioxide + 1-hexadecanol systems. The experimental p – T projections of the S–L–G lines were also correlated by the Peng–Robinson equation of state and the van der Waals type mixing rules with two binary interaction parameters introduced into attraction term and size terms, respectively. The present model gave good correlation results for all of the experimental S–L–G lines with maximum average absolute relative deviations of 0.075% for the carbon dioxide + tetradecanoic acid system, 0.14% for the carbon dioxide + hexadecanoic acid system and 0.28% for the carbon dioxide + 1-hexadecanol system, respectively.

The pressure p−temperature T projections of solid−liquid−gas (S−L−G) three-phase coexistence lines for the carbon dioxide + octadecanoic acid (stearic acid; C18H36O2) system and the carbon dioxide + 1-octadecanol (stearyl alcohol; C18H38O) system were measured by the first melting point method in which the initial appearance of the liquid phase was observed. The experimental p−T projections of the S−L−G lines were also correlated by the Peng−Robinson equation of state and the van der Waals type mixing rules with two binary interaction parameters introduced into attraction term and size terms, respectively. The present model gave good correlation results for all of the experimental S−L−G lines with maximum average absolute relative deviations of 0.32 % for the carbon dioxide + octadecanoic acid system and 0.32 % for the carbon dioxide + 1-octadecanol system.

In this study, two different nano-structured samples of the FeTi compound were prepared by mechanical alloying and mechanical grinding. For these samples, kinetics of the initial rate of hydrogen absorption, and the equilibrium hydrogen pressure as a function of hydrogen concentration were measured. Mechanical alloying of Fe and Ti atoms produced the FeTi compound powder samples with microstructures of a mixture of nano-structured FeTi grains and amorphous phases. This sample exhibited a high initial rate of hydrogen absorption even at 298 K, however, a strongly reduced hydrogen storage capacity. Mechanical grinding of the FeTi produced samples of particles with a particular microstructure: surface layers with a mixture of nano-structured FeTi grains and amorphous phases, and a single crystalline phase of FeTi below the surface layers for each particle. This sample exhibited a high initial rate of hydrogen absorption without a significant reduction of the hydrogen storage capacity compared with that of the standard FeTi sample. This mechanical grinding treatment was found to be an effective method of surface modification to improve the initial activation of the FeTi hydrogen storage alloy.