[en] Highlights: • Flow characteristics of notches are studied using CFD simulation and experiment. • Test data is fitted by least square method to analyze discharge coefficient. • The stable value of discharge coefficient is deduced. • Effects of groove shape on steady flow force and throttling stiffness are performed. • The groove shape has significant effects on the flow characteristics. - Abstract: The grooves of notches of hydraulic spool valves are usually designed into various shapes for their desired flow characteristics. The aim of this paper is to clarify the effects of the groove shape on the flow characteristics through computational fluid dynamics (CFD) and experimental investigations. The RNG k–ε turbulence model is used to simulate the pressure distributions of the flow fields inside three notches with their corresponding typical structural grooves in order to analyze the changes of restricted locations along with the openings and, furthermore, to calculate the flow areas of the notches. The accuracy of the employed model is demonstrated by comparing the computational results with the experimental data. Additionally, the flow rate vs. pressure drop data obtained from the experiment is fitted by least square method. On this basis, the discharge coefficient as a function of groove geometry, flow condition, fitting coefficients and its stable value is deduced, proving to be quite consistent with the experimental result. Thanks to the jet flow angles estimated by CFD simulation, the steady flow forces are calculated, which show good agreement with the experimental results except for some small differences. Finally, the throttling stiffness of the three notches is investigated, with that of divergent U-shape groove falls between spheroid-shape groove and triangle-shape groove. Similar results are found for steady flow force. The results indicate that the groove shape has significant effects on the flow characteristics (flow area, discharge characteristic, jet flow angle, steady flow force and throttling stiffness) of spool valve

[en] Iodine-123-labeled 15-(p-iodophenyl)-3-(R,S)-methyl pentadecanoic acid (¹²³I-BMIPP) is widely used to detect myocardial metabolic changes, but the preferred energy substrates in the myocardium would be expected to be altered in the presence of metabolic disorders such as diabetes mellitus (DM). We investigated the metabolism of branched-chain fatty acids in the myocardium of rats with DM. Streptozotocin-induced DM rats were examined 48 h (acute; AD) and 6 weeks (chronic; CD) after injection of streptozotocin. Hearts were excised 15 min or 60 min after injection of 0.185 MBq of ¹²⁵I-BMIPP, followed by homogenization in an EDTA-Tris buffer. The homogenates were subjected to differential centrifugation to obtain the mitochondrial (MF) and cytoplasmic (CF) fractions. Myocardial ¹²⁵I uptake tended to increase in the AD group, but the change was not significant. Myocardial ¹²⁵I uptake at 15 min was significantly lower in the CD group than in the control group, even in the insulin-treated rats (control (CC), 4.4±0.4; not treated (CDN), 3.3±0.5; insulin-treated (CDI), 3.4±0.4 x 10⁴ cpm/g, p<0.05 in each case). The ¹²⁵I count value corrected for the blood count (counts/min (cpm) per g of protein divided by blood cpm) in the MF decreased by 40% at 60 min in the CC group, but increased by 60% in the CDN group. The results of the present study suggest that the myocardial uptake of branched-chain fatty acids is decreased in rats with chronic diabetes, probably as a result of mitochondrial dysfunction. (author)

[en] With the improvement of radar technology, performance of traditional chaff jamming is decreasing constantly. Aiming at the imbalances between the development of chaff jamming and radar technology, a new chaff jamming technology—nano-chaff — is proposed. The basic characteristics of nano-chaff were analyzed before introducing the concept of ideal chaff bomb and studying its scattering characteristics. Simulation results show that, nano-chaff has low radiant efficiency, for which its advantage of loading quantity can make up. Additionally, compared with traditional chaff, it can enhance the RCS of single ideal chaff cartridge. The result can provide some theory basis for applied research subsequently. (paper)

[en] Objective: To investigate the effect of inversion time (TI) on flow-sensitive alternating inversion recovery (FAIR) perfusion imaging of spinal bone marrow (SBM), and evaluate the reproducibility of blood flow (BF) measurements using this technique. Methods: Twenty four healthy volunteers without lumbar and other disease with clinical and MR studies were prospectively included. The first 14 healthy volunteers were included to study the effect of TI on ASL perfusion imaging of SBM to get the optimized TI, the remaining 10 volunteers were included to investigate the reproducibility of the SBM arterial spin labeling (ASL) scan protocol. The optimized TI of FAIR spinal bone marrow perfusion experiment was carried out on 14 healthy volunteers on 3.0 T magnet, two adjacent vertebral bodies were orderly selected from each volunteer to measure the AM and the SNR of FAIR perfusion MRI with 5 different TIs (800, 1000, 1200, 1400, 1600 ms), and the vertebral bodies selected order were determined by the order of the subjects enrolled. In addition, FAIR perfusion spinal vertebral BF measurements were repeated in last 10 healthy subjects on L4 or L5 by reposition immediately, paired t test and reproducibility statistics (included within-patient standard deviation (wSD) and within-patient coefficient of variation (WCV)) were used to analyze the test-retest experiment reproducibility. Result: TI optimization experiments total included 28 vertebral bodies, when TI (ms) was chose as 800, 1000, 1200, 1400, 1600, ms respectively, the mean ΔM of spinal bone marrow were 20.8 ± 9.0, 29.0 ± 10.9, 36.4 ± 12.5, 26.2 ± 10.2 and 23.8 ± 11.5, and the mean SNR were 2.0 ± 1.0, 2.3 ± 0.8, 2.4 ± 1.0, 2.3 ± 0.8 and 2.0 ± 0.7. With TI increasing, AM and SNR increased first and then decreased, the maximum values of both were achieved when the TI near 1200 ms. Test-retest experiment were carried on 10 vertebral bodies eventually, and two measurements of spinal vertebral BF perfusion before and after were (108.9 ± 4.6) and (109.2 ± 4.6) ml·100g^-1·min^-1, respectively, and no significant difference was found (t = -0.157, P = 0.879), wCV of the measurements was 3.28% (3.57/109.06). Conclusion: The optimal TI was 1200 ms for spinal bone marrow ASL perfusion image, at which the maximum AM, higher SNR, and good reproducibility for the FAIR spinal bone marrow perfusion imaging can be achieved. (authors)

[en] A quasi-linear formalism is developed for relativistic particles. It is self-consistent including spatial diffusion. An attempt is made to simulate the process of electron cyclotron resonant heating (ECRH) and electron cyclotron current drive (ECCD) for the HL-2A tokamak. Temperature oscillating regimes in Tore Supra diagnosed by MHD activity seem to be reproduced in the simulation. The special feature in this paper is to see the resonance in the long time scale for relativistic plasma. (physics of gases, plasmas, and electric discharges)

[en] The coherent control of molecular alignment and orientation by a femtosecond two-color laser pulse is studied theoretically. The effect of the carrier-envelope phase of the femtosecond two-color laser pulse on molecular alignment and orientation is discussed, and it is shown that the enhancement or suppression of the molecular orientation can be coherently manipulated by precisely controlling the carrier-envelope phase of the femtosecond two-color laser pulse. In addition, the time-dependent angular distributions of the molecular axis are presented

[en] Three-dimensional (3D) patterns are obtained for the first time in dielectric barrier discharge by a special designed device with “H” shaped gas gap which consists of a single gas layer gap and two double gas layer gaps. Three dimensional spatiotemporal characteristics of discharge are investigated by photomultiplier and intensified charge-coupled device camera. Results show that the discharge first generates in the single gas layer gap and the coupled filaments in the double gas layer gap present the simultaneity characteristics. The formation of 3D patterns is determined by the distribution of the effective field of the applied field and the wall charge field.

[en] Objectives: This study was conducted to investigate the risk factors for pulmonary abscess-related empyema by investigating the clinical characteristics and chest computed tomography imaging features of patients with pulmonary abscesses. Methods: We retrospectively analyzed the chest computed tomography findings and clinical features of 101 cases of pulmonary abscess, including 25 cases with empyema (the experimental group) and 76 cases with no empyema (the control group). The potential risk factors for pulmonary abscess-related empyema were compared between the groups by using univariate and multivariate logistic regression analyses. Results: The incidence of pulmonary abscess-related empyema was 24.8% (25/101). Univariate analysis showed that male gender, diabetes, pleuritic symptoms, white blood cells > 10 x >10⁹/L, albumin level <25 g/L, and positive sputum cultures were potential clinical-related risk factors and that an abscess 45 cm in diameter and transpulmonary fissure abscesses were potential computed tomography imaging-related risk factors for pulmonary abscess-related empyema. Multivariate logistic regression analysis showed that transpulmonary fissure abscesses (odds ratio=9.102, p=0.003), diabetes (odds ratio=9.066, p=0.003), an abscess 45 cm in diameter (odds ratio=8.998, p=0.002), and pleuritic symptoms (odds ratio=5.395, p=0.015) were independent risk factors for pulmonary abscess-related empyema. Conclusions: Transpulmonary fissure abscesses, diabetes, giant pulmonary abscesses, and pleuritic symptoms increased the risk of empyema among patients with pulmonary abscesses. (author)

[en] The aim of this study was to clarify the influence of inter-metallic compounds (IMCs) on the electrical conductivity of Cu/Al joint. The longitudinal resistance and the lateral current distribution at flash welded and diffusion brazed Cu/Al joint interfaces were investigated using four-point method and conductive atomic force microscopy, respectively. A 2μm Cu₉Al₄/CuAl₂ layer was formed in both joints. The IMCs layer was homogenous and the current distribution interface was planar at diffusion brazed joint. However, the IMCs layer was discontinuous and the current distribution interface was non-planar at flash welded joint. After heat treatment at 350°C for 500h, the thickness of interfacial layer was increased to 50μm. CuAl and a short crack were newly formed in the diffusion brazed joint. CuAl, (Cu,Al)_x O_y and a long crack were newly formed in the flash welded joint. A multilayer current distribution was found at both heat treated joints. The resistivity of all Cu/Al joints was higher than that of copper and lower than that of aluminum. The resistivity of diffusion brazed joint was the lowest, which was lower than the theoretical value. The resistivity of the heat treated flash welded joint was the highest among all the joints. (author)

[en] We present a novel stackable luminescent device integrating a blue light emitting diode (LED) with a red organic LED (OLED) in series. The anode of the OLED is connected with the cathode of the LED through a via in the insulation layer on the LED. The LED–OLED hybrid device is electroluminescent and two electroluminescence (EL) peaks (the blue peak around 454 nm and the red peak around 610 nm) are observed clearly. The effect of the indium tin oxide (ITO) layer on the device performance is analyzed. Compared with the individual LED and OLED, their combination shows great potential applications in the field of white lighting, plant lighting, and display. (paper)