Observation of spin-space quantum transport induced by an atomic quantum point contact

冷却原子の量子状態を制御し新たな「流れ」を実現 --「原子回路」で電子の流れをシミュレーションする--. 京都大学プレスリリース. 2021-11-22.Quantum transport is ubiquitous in physics. So far, quantum transport between terminals has been extensively studied in solid state systems from the fundamental point of views such as the quantized conductance to the applications to quantum devices. Recent works have demonstrated a cold-atom analog of a mesoscopic conductor by engineering a narrow conducting channel with optical potentials, which opens the door for a wealth of research of atomtronics emulating mesoscopic electronic devices and beyond. Here we realize an alternative scheme of the quantum transport experiment with ytterbium atoms in a two-orbital optical lattice system. Our system consists of a multi-component Fermi gas and a localized impurity, where the current can be created in the spin space by introducing the spin-dependent interaction with the impurity. We demonstrate a rich variety of localized-impurity-induced quantum transports, which paves the way for atomtronics exploiting spin degrees of freedom

The Japanese Clinical Practice Guideline for acute kidney injury 2016

Acute kidney injury (AKI) is a syndrome which has a broad range of etiologic factors depending on different clinical settings. Because AKI has significant impacts on prognosis in any clinical settings, early detection and intervention are necessary to improve the outcomes of AKI patients. This clinical guideline for AKI was developed by a multidisciplinary approach with nephrology, intensive care medicine, blood purification, and pediatrics. Of note, clinical practice for AKI management which was widely performed in Japan was also evaluated with comprehensive literature search

Active omni wheel possessing seamless periphery and omnidirectional vehicle using it

Vehicles that are capable of achieving omnidirectional movement will work very efficiently in factories and warehouses. To meet this requirement, various omnidirectional vehicles have been proposed, but the wheel mechanism makes precise movement difficult. The active omni wheel (AOW), which can drive itself in an arbitrary direction at any time, can address this issue, but our previous design had mechanical vibration and acoustic noise due to gaps in the outer circumference of the wheel, and its complicated structure had a large number of parts. To solve these problems, this study developed a new AOW possessing a seamless periphery and simple structure. By using barrel-shaped friction-driven outer rollers arranged alternately on the left and right sides of the wheel, gaps between the outer rollers are eliminated and a smooth periphery is realized. Additionally, the power transmission paths were simplified to reduce the number of parts. This paper explains the AOW structure and then presents analyses of structural conditions and kinematics of the AOW. A two-wheel-drive omnidirectional vehicle using the AOW was built and kinematically analyzed. Finally, experiments using the developed AOW and vehicle were conducted and their effectiveness was verified

HOx budgets during HOxComp: a case study of HOx chemistry under NOx-limited conditions

[1] Recent studies have shown that measured OH under NOx-limited, high-isoprene conditions are many times higher than modeled OH. In this study, a detailed analysis of the HOx radical budgets under low-NOx, rural conditions was performed employing a box model based on the Master Chemical Mechanism (MCMv3.2). The model results were compared with HOx radical measurements performed during the international HOxComp campaign carried out in Jülich, Germany, during summer 2005. Two different air masses influenced the measurement site denoted as high-NOx (NO, 1-3 ppbv) and low-NOx (NO, \u3c 1 ppbv) periods. Both modeled OH and HO2 diurnal profiles lay within the measurement range of all HOx measurement techniques, with correlation slopes between measured and modeled OH and HO2 around unity. Recently discovered interference in HO2 measurements caused by RO2 cross sensitivity was found to cause a 30% increase in measured HO2 during daytime on average. After correction of the measured HO2 data, the model HO2 is still in good agreement with the observations at high NOx but overpredicts HO2 by a factor of 1.3 to 1.8 at low NOx. In addition, for two different set of measurements, a missing OH source of 3.6 ± 1.6 and 4.9 ± 2.2 ppb h−1 was estimated from the experimental OH budget during the low-NOx period using the corrected HO2 data. The measured diurnal profile of the HO2/OH ratio, calculated using the corrected HO2, is well reproduced by the MCM at high NOx but is significantly overestimated at low NOx. Thus, the cycling between OH and HO2 is better described by the model at high NOx than at low NOx. Therefore, similar comprehensive field measurements accompanied by model studies are urgently needed to investigate HOx recycling under low-NOx conditions

Technical Note: Formal blind intercomparison of OH measurements: results from the international campaign HoxComp

Hydroxyl radicals (OH) are the major oxidizing species in the troposphere. Because of their central importance, absolute measurements of their concentrations are needed to validate chemical mechanisms of atmospheric models. The extremely low and highly variable concentrations in the troposphere, however, make measurements of OH difficult. Three techniques are currently used worldwide for tropospheric observations of OH after about 30~years of technical developments: Differential Optical Laser Absorption Spectroscopy (DOAS), Laser-Induced Fluorescence Spectroscopy (LIF), and Chemical Ionisation Mass Spectrometry (CIMS). Even though many measurement campaigns with OH data were published, the question of accuracy and precision is still under discussion.<br> <br> Here, we report results of the first formal, blind intercomparison of these techniques. Six OH instruments (4~LIF, 1~CIMS, 1~DOAS) participated successfully in the ground-based, international HOxComp campaign carried out in Jülich, Germany, in summer 2005. Comparisons were performed for three days in ambient air (3~LIF, 1 CIMS) and for six days in the atmosphere simulation chamber SAPHIR (3~LIF, 1~DOAS). All instruments were found to measure tropospheric OH concentrations with high sensitivity and good time resolution. The pairwise correlations between different data sets were linear and yielded high correlation coefficients (<i>r</i><sup>2</sup>=0.75−0.96). Excellent absolute agreement was observed for the instruments at the SAPHIR chamber, yielding slopes between 1.01 and 1.13 in the linear regressions. In ambient air, the slopes deviated from unity by factors of 1.06 to 1.69, which can partly be explained by the stated instrumental accuracies. In addition, sampling inhomogeneities and calibration problems have apparently contributed to the discrepancies. The absolute intercepts of the linear regressions did not exceed 0.6×10<sup>6</sup> cm<sup>−3</sup>, mostly being insignificant and of minor importance for daytime observations of OH. No relevant interferences with respect to ozone, water vapour, NO<sub>x</sub> and peroxy radicals could be detected. The HOxComp campaign has demonstrated that OH can be measured reasonably well by current instruments, but also that there is still room for improvement of calibrations