通过水溶液还原法用抗坏血酸制备纳米铜颗粒(英文)

通过水溶液还原法用抗坏血酸还原Cu2+制备纳米铜颗粒,并研究溶液pH和Cu2O平均粒径对纳米铜颗粒制备的影响。在溶液pH值为3、5和7时,可制得铜颗粒,并且在pH=7时制得的铜颗粒粒径最小。在溶液pH为9和11时无法制得铜颗粒。Cu2O的平均粒径能影响铜粉的粒径。Cu2O的平均粒径越大,得到的铜颗粒越大。通过对反应过程中不同时间点收集的样品进行XRD分析,可探索出反应的进程。在反应过程中,Cu(OH)2首先作为前驱体出现,然后被还原为Cu2O,最后被还原为铜颗粒。     

Lewis acid-assisted anionic polymerization of methyl cyclobutene-1-carboxylate

A cyclobutene monomer, methyl cyclobutene-1-carboxylate (MHCB), has been polymerized by anionic addition polymerization. Although MHCB may be regarded as a member of α,β-disubstituted acrylate derivatives which are reluctant to undergo anionic addition polymerization, anionic polymerization of MHCB with tert-butyllithium (t-BuLi) in combination with bis(2,6-di-tert-butylphenoxy)ethylaluminum [EtAl(ODBP)₂] in toluene at −78 °C gives a polymer consisting of 1,2-linked cyclobutane ring in the main chain with narrow molecular weight distribution. Copolymerization of MHCB and methyl methacrylate with t-BuLi/EtAl(ODBP)₂ proceeds in a monomer-selective and living manner to form a block-like copolymer. Poly(MHCB) undergoes unique thermal reaction through ring opening of the cyclobutane units to form CC bonds between successive monomer units.     

Direct observation of X-ray induced atomic motion using scanning tunneling microscope combined with synchrotron radiation

X-ray induced atomic motion on a Ge(111)-c(2 x 8) clean surface at room temperature was directly observed with atomic resolution using a synchrotron radiation (SR)-based scanning tunneling microscope (STM) system under ultra high vacuum condition. The atomic motion was visualized as a tracking image by developing a method to merge the STM images before and after X-ray irradiation. Using the tracking image, the atomic mobility was found to be strongly affected by defects on the surface, but was not dependent on the incident X-ray energy, although it was clearly dependent on the photon density. The atomic motion can be attributed to surface diffusion, which might not be due to core-excitation accompanied with electronic transition, but a thermal effect by X-ray irradiation. The crystal surface structure was possible to break even at a lower photon density than the conventionally known barrier. These results can alert X-ray studies in the near future about sample damage during measurements, while suggesting the possibility of new applications. Also the obtained results show a new availability of the in-situ SR-STM system.     

A system for LogD screening of 96-well plates using a water-plug aspiration/injection method combined with high-performance liquid chromatography-mass spectrometry

A system for screening of the octanol/water distribution coefficient (LogD) using automatic sampling of 96-well plates was developed. The high-speed assay for LogD (HSLogD) screening uses a water-plug aspiration/injection method combined with high-performance liquid chromatography-mass spectrometry (HPLC-MS). The method is useful for LogD analysis of highly hydrophobic compounds, where the concentration of the compound in the octanol phase is much higher than that in the water phase. In the case of LogD analyses, the conventional shake-flask method has been widely used, but it is difficult to increase the throughput of the shake-flask method because the lower water phase is carefully separated by manual separation without contamination of the upper octanol phase. We attempted to develop an automatic sampling method instead of manual separation to increase the throughput of the measurement. In initial attempts at automatic sampling, contamination of the octanol phase occurred when sampling of the water phase was made. This was because the octanol phase entered the sampling needle as it passed through to the lower water phase. This contamination was prevented by taking up a few microliters of water into the needle as a plug before sampling of the water phase (the water-plug aspiration/injection method). LogD values of some common drugs measured using the HSLogD agreed with reported LogD values (0 < LogD < 5).     

Long-term clinical effect of nilvadipine in patients with chronic heart failure: a double-blind placebo-controlled study

The long-term effect of calcium channel blockers on chronic heart failure is disappointing, probably because of reflex sympathetic activation through arterial vasodilation. However, nilvadipine may be beneficial for treatment of chronic heart failure since this drug has minimal effects on sympathetic activation. In this study, the effects of 12-week administration of nilvadipine or placebo on symptoms of heart failure and cardiac function were investigated in 23 patients with mild-to-moderate chronic heart failure in a double-blind trial. The patients were randomly assigned to either a nilvadipine group (16 mg daily) or a placebo group. Intergroup comparisons did not show significant differences in any parameters. Serious adverse effects were not observed during the study. Thus, this study failed to show any beneficial effect of nilvadipine in the long-term treatment of patients with chronic heart failure. We conclude that the long-term administration of nilvadipine (16 mg daily) is neither effective nor harmful in the treatment of patients with chronic heart failure.     

Plasma arc welding of pipelines: A study to optimise welding conditions for horizontal fixed joints of mild steel pipes

A plasma arc process was applied to the welding of mild steel pipes (thickness: 6·4 mm, outside diameter: 406·4 mm) and the effect of different welding parameters on the shape of welds and consistency of defects was studied in the flat, vertical and overhead positions.In conventional plasma arc welding conditions, full penetration and continuous bead formation were obtained in a range of conditions which tended towards lower plasma gas flow rates and higher travelling speeds as the welding current was increased. In the overhead position, the penetration bead presented deep continuous concaves.In the vertical-up position, it was not possible to obtain a range of welding conditions assuring full penetration and continuous bead formation.The experiment relating to the effect of the pulsating welding current on the shape and defects of welds disclosed that the use of pulse frequencies lower than 4 Hz makes the penetration bead less uniform than the use of higher pulse frequencies. It was also found that the use of high pulse frequencies results in a remarkable effect in the vertical-up position.Welding using argon gas back shielding made the penetration bead more uniform in height and width. By decreasing the atmospheric pressure inside the pipe, concaves in the penetration bead could be reduced, particularly in the overhead position.From the results described above, it is considered that pulsating welding current and the backing method are effective in obtaining a good bead over the entire circumference of mild steel by plasma keyhole welding.The experiment also revealed that when plasma arc welding is applied, mild steel pipes can be welded at four times the productivity that can be expected of the conventional GMA welding.Therefore plasma arc welding equipment and appropriate jigs will be made shortly for practical application.     

In‐Air finger motion interface for mobile devices with vibration feedback

In this paper, we propose the ‘in‐air finger motion interface’, which solves a problem users face in interacting with mobile devices. The interface uses only a single small camera to track the three‐dimensional (3D) position of the user's finger. The finger region is robustly extracted by using flashing infrared light‐emitting diodes (LEDs) and by obtaining the difference image between an illuminated image and a nonilluminated image. The movement of the finger is modeled by transformation of a finger image, and its parameters are accurately estimated by iterative template matching. As a result of the evaluation, an operating area 131% larger than the size of the display and accuracy of input action of 0.6 mm in the x‐direction are realized. Finally, to investigate the effect of vibration feedback, we conducted a study and found that vibration feedback significantly reduces the average time to finish the task as well as the number of input errors. © 2014 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.     

NIR spectral imaging with discriminant analysis for detecting foreign materials among blueberries

The visualization of foreign materials (leaves and stems) in frozen blueberries was achieved by near infrared (NIR) spectral imaging and discriminant analysis. As a preliminary experiment, NIR spectroscopy of a sample surface was carried out to determine the effective wavelengths for differentiating foreign materials from blueberries in the NIR region. The optimal illumination wavelengths for distinguishing foreign materials were determined to be 1268 and 1317 nm, according to the results of a discriminant analysis of absorbance spectra. Next, absorbance images of areas containing foreign materials and blueberries were acquired by NIR spectral imaging at these two wavelengths. Nine thousand eight hundred and fifty pixels of a blueberry area and 10,107 pixels of a foreign material area were picked randomly from the absorbance images. Discriminant analysis was applied to the absorbance of pixels within the area of interest to determine the discriminant function and threshold value for image binarization. Finally, binary images were obtained by applying the discriminant function and threshold value to each pixel of the absorbance images taken at 1268 and 1317 nm. Foreign materials were clearly distinguished from blueberries as black areas in the binary images.