Convergence acceleration of series through a variational approach

By means of a variational approach we find new series representations both for well-known mathematical constants, such as π and the Catalan constant, and for mathematical functions, such as the Riemann zeta function. The series that we have found are all exponentially convergent and provide quite useful analytical approximations. With limited effort our method can be applied to obtain similar exponentially convergent series for a large class of mathematical functions.     

Sliding acceleration of water droplets on a surface coated with fluoroalkylsilane and octadecyltrimethoxysilane

Both fluoroalkylsilane (FAS) and octadecyltrimethoxysilane (ODS) were coated on oxidized silicon wafers using soaking and CVD method. Smooth coatings with Ra values of less than 1 nm were attained. The slope of the sliding acceleration against the inverse of the droplet mass showed an inflection point. That point shifted to the direction of smaller droplets with decreasing FAS ratio to ODS. The water droplets’ length was increased when the sliding velocity was increased. Fluoroalkylsilane addition to ODS increases the interaction between water and the hydrophobic surface. Results showed that the sliding acceleration of a water droplet depends strongly on the surface ratio of these silanes.     

Post-accelerator LINAC design for the VECC RIB project

Variable Energy Cyclotron Centre (VECC) is presently developing an ISOL post-acclerator type of RIB facility. The scheme utilises the existing K=130 room temperature variable energy cyclotron machine as the primary accelerator for the production of RIBs and radio frequency quadrupole (RFQ) and LINAC modules for the post-acceleration. The design aspects of these post-accelerator LINAC modules will be discussed in this paper.     

Convergence of consistent and inconsistent finite difference schemes and an acceleration technique

This paper states and generalizes in part some recent results on finite difference methods for Dirichlet problems in a bounded domain Ω which the author has obtained by himself or with coworkers. After stating a superconvergence property of finite difference solution for the case where the exact solution u belongs to , it is remarked that such a property does not hold in general if . Next, a convergence theorem is given for inconsistent schemes under some assumptions. Furthermore, it is shown that the accuracy of the approximate solution can be improved by a coordinate transformation. Numerical examples are also given.     

Beschleunigungsreaktionen von Neutronen

Acceleration of neutrons by isomeric nuclei. The inelastic neutron acceleration (INNA) by long living isomeric nuclei is studied. The theoretical estimates of the INNA cross-sections for thermal neutrons for a number of isomers give the values in the range 0.1 - 10²b. Inelastic acceleration of thermal neutrons was observed by ^152mEu and ^180mHf, and confirmed the high value of the INNA cross-sections. As a result of the high probability of acceleration some isomeric nuclei ^113mIn, ^115mIn, are not usual moderators but accelerators of neutrons. The use of the INNA reaction for the study of high excited levels and the nature of various nuclear hindrances are discussed.     

Chiral,pH responsive hydrogels constructed by N‐Acryloyl‐alanine and PEGDA/α‐CD inclusion complex: preparation and chiral release ability

Chiral, pH‐responsive hydrogels are constructed by poly(ethylene glycol) diacrylate/α‐cyclodextrin (PEGDA/α‐CD) inclusion complex and L‐N‐acryloyl‐alanine or D‐N‐acryloyl‐alanine (L‐NAA or D‐NAA) by an effective free radical polymerization approach. PEGDA containing two C=C end groups was used simultaneously to introduce α‐CD units in the resulting hydrogels and to serve as a cross‐linking agent, by which forming the designed hydrogels in quantitative yield. Hydrophilic α‐CD moieties acted as pore‐forming agent, while the L(D)‐NAA‐based polymer chains bearing –COOH groups enabled the hydrogels to display remarkable swelling–deswelling behavior in response to pH variation. The chiral NAA monomer‐derived polymer chains rendered the hydrogels with intriguing optical activity, according to circular dichroism spectra. Scanning electron microscopy revealed the uniformly porous microstructures of hydrogels. More remarkably, the L‐NAA‐based hydrogels preferentially adsorbed trans‐4‐hydroxy‐d ‐proline and preferentially released trans‐4‐hydroxy‐l ‐proline, while D‐NAA‐based hydrogels provided opposite results. The hydrogels also demonstrated remarkable enantioselective release ability towards chiral drug ibuprofen. Copyright © 2015 John Wiley & Sons, Ltd.     

太赫兹半导体探测器研究进展

太赫兹（THz）探测器是THz技术应用的关键器件之一．基于半导体的全固态THz量子阱探测器（THzQWIP）具有探测响应速度快、制作工艺成熟、体积小和易集成等优点．文章简要介绍了THz探测器的分类和特点，重点介绍了THzQWIP的工作原理和研究进展．     

Establishment of Illuminance Scale at UME with an Accurately Calibrated Radiometer

Traceability in illuminance measurements at the National Metrology Institute of Turkey (TüBITAK-UME) was established in 2003 with a detector-based realization. The new measurement technique was developed for the determination of illuminance responsivity and upgrating of the illuminance scale. The unit of the illuminance responsivity, in A/lx, was measured with an expanded uncertainty of 0.2% (k = 2) by supplying using the developed scanning technique for the calculation of color correction factor. The surface of a radiometer was scanned using a double-monochromator facility upgraded with an x-y scanning system. The illuminance responsivity as a function of bandpass and temperature were also investigated in this study. To use a radiometer in the photometric applications of metrology, a light-sensitive device, a so-called trap detector, was characterized by measuring the absolute responsivity, the non-linearity, and spatial non-uniformity.     

低加速度灵敏度水听器

本文介绍了一种用于拖曳线列阵声呐的压电陶瓷型水听器，我们在提高水听器工作稳定性与可靠性，并确保水听器有较高接收灵敏度的前提下，进行了水听器的结构方案优化设计，以降低水听器的加速度灵敏度，研制的水听器接收灵敏度为－１９３ｄＢ，在２０－１０００Ｈｚ频段内灵敏度起伏为１．２ｄＢ，加速度灵敏为－７０ｄＢ。