BECOOL: Ballooning eigensolver with COOL finite elements

An incompressible variational ideal ballooning mode equation is discretized with the COOL finite element discretization scheme using basis functions composed of variable order Legendre polynomials. This reduces the second order ordinary differential equation to a special block pentadiagonal matrix equation that is solved using an inverse vector iteration method. A benchmark test of BECOOL (Ballooning Eigensolver using COOL finite elements) with second order Legendre polynomials recovers precisely the eigenvalues computed by the VVBAL shooting code. Timing runs reveal the need to determine an optimal lower order case. Eigenvalue convergence runs show that cubic Legendre polynomials construct the optimal ballooning mode equation for intensive computations.     

Group theoretic properties of Rijndael-like ciphers

We provide conditions for which the round functions of an ?-bit Rijndael-like block cipher generate the alternating group on the set {0,1}^?. These conditions show that the class of Rijndael-like ciphers whose round functions generate the alternating group on their message space is large, and includes both the actual Rijndael and the block cipher used by the compression function of the Whirlpool hash function. The result indicates that there is no trapdoor design for a Rijndael-like cipher based on the imprimitivity of the group action of its proper round functions which is difficult to detect.     

Interfacial change on morphological transitions in styrene-isoprene diblock copolymer

The specific interfacial area (S/V) and interfacial thickness in each microstructure of styrene-isoprene diblock copolymer were estimated by analyzing the deviations from Porod’s law. The thermally induced phase transitions proceeded from lamellae (L) to hexagonally ordered cylinder (HEX), via hexagonally perforated layer (HPL) and gyroid (G). The S/V ratio increased stepwise at the order-order transition (OOT) from L to HEX, via HPL and G. The S/V data can be utilized for OOT determination.     

Synthesis and characterization of a novel water-soluble mid-chain macrophotoinitiator of polyacrylamide by Ce(IV)/HNO3 redox system

A new water-soluble mid-chain macrophotoinitiator of polyacrylamide (PAAm) has been synthesized by redox polymerization. The polymerization of acrylamide (AAm) initiated by dihydroxy functional photoinitiator namely, 2-hydroxy-1-[4-(2-hydroxyethoxy)phenyl]-2-methyl propan-1-one (HE-HMPP), Irgacure 2959, in combination with cerium(IV) ammonium nitrate has been investigated in aqueous nitric acid. The effects of HE-HMPP, AAm, and Ce(IV) concentrations on the polymerization rate were investigated. The photodegradation and IR, ¹H NMR, UV, and fluorescence spectroscopic studies revealed that polyacrylamide with desired photoinitiator functionality in the middle of the chain were obtained. This prepolymer was used in photoinduced free radical polymerization of methyl methacrylate (MMA) to produce PAAm-PMMA block copolymer.     

Flow-shop scheduling with setup and assembly operations

A scheduling model for a production system including machining, setup and assembly operations is considered. Production of a number of single-item products is ordered. Each product is made by assembling a set of several different parts. First, the parts are manufactured in a flow-shop consisting of multiple machines. Then, they are assembled into products on a single assembly stage. Setup operation and setup time are needed when a machine starts processing the parts or it changes items. The operations are partitioned into several blocks. Each block consists of the machining operations, the setup operations, and the assembly operation(s) for one or several products. The parts of the same item in a block are processed successively. The objective function is the mean completion time for all products. We consider a problem to partition the operations into blocks and sequence the parts in each block so as to minimize the objective function. Solution procedures using pseudo-dynamic programming and a branch-and-bound method are proposed. Computational experiments are carried out to evaluate the performance of the solution procedures. It has been found that a good near-optimal schedule is obtained efficiently by the proposed solution procedures.     

适用于ASIC的高速低功耗逻辑单元

本文介绍一种ECL电路结构形式的ASIC逻辑单元的设计和应用。该单元使用2.5V的电源,内部开关电流设计为0.5mA,逻辑摆幅设计为340mV,输入输出均采用双向互补信号。它具有信息的基本记忆功能,用它进行多级组合配套设计,可制作不同模数的分频器、寄存器和计数器等。设计灵活,功能强,电路速度快,功耗低,仅为具有相同功能的普通ECL电路的1/30。这些电路可用在通讯机、电子控制系统、电子测量系结中作高速数字锁相环,数字信号处理的专用集成电路。     

Performance of Systematic Distance-4 Binary Linear Block Codes with Continuous Phase Frequency Shift Keying over MIMO Systems

Codes with full information rate (optimal), for example Hamming codes, provide the highest possible code rate R (R = k/n where k and n are the code dimension and length respectively) and it is an important property for a block code. Recently, the Systematic Distance-4 (SD-4) codes are proposed that allows generating all the optimal Hamming distance-4 binary linear block codes. Continuous Phase Frequency Shift Keying (CPFSK) provides low spectral occupancy and is suitable for power and bandwidth-limited channels such as satellite communication channels. MIMO technique is essential for modern wireless communication systems. In this article, we evaluated the error performances of SD-4 codes utilizing CPFSK modulation over MIMO Rician and Rayleigh channels via computer simulations and obtained outstanding results regarding coding gain.     

Fundamental error analysis and geometric interpretation for block truncation coding techniques

Various variants and hybrid approaches evolved from the origin of Delp and Mitchell's block truncation coding (BTC) or moment preserving quantizer (MPQ) have formed a niche as an effective and simple image compression methodology with attractive coding performance achieved at moderate bitrates. As BTC is still lacking a fundamental error analysis, in this paper we present some fundamental insights regarding one-bit (or two-level) BTC's truncation error by providing mathematical analysis as well as novel geometric interpretation. We further show that the mean-square error (MSE) of Lema and Mitchell's absolute moment block truncation coding (AMBTC) is always bounded below (i.e., less than or equal to) that of BTC. Therefore, with additional advantages in computation and implementation, AMBTC is always superior. Furthermore, we developed a new adaptive equal sign position optimization (ESPO) algorithm for optimum pixel classification. Our quantization error analysis shows that incorporating the ESPO algorithm into conventional AMBTC or BTC achieves minimum MSE in either case.     

Effects of cationic head groups of ionic liquid on micellization in aqueous solution of PEO-PPO-PEO triblock copolymer

The interaction of ionic liquids (ILs) with non-ionic triblock copolymer, Pluronic® P123 in aqueous solutions has been investigated using DLS, surface tension, and viscosity measurements. The addition of ILs increased the Critical Micelle Concentration (CMC) of P123, which appears to be logistic. As the added IL enhances the solubility of PPO moiety (and PEO), which makes them to behave like a more hydrophilic block copolymer that would be micellized at high copolymer concentration. The DLS data is in good agreement to the results observed from surface tension measurements. Viscosity results show the propensity in micellar size reduction upon addition of ILs, and hence, intrinsic viscosity decreases as compared to pure P123 aqueous solution. The results are studied and discussed as a function of cationic head groups of N-octyl-pyridinium/imidazolium chloride based ILs.     

Synthesis and MALDI-TOF-MS of PS-PMA and PMA-PS block copolymers

The synthesis of well-defined block copolymers from styrene and methyl acrylate via ATRP is discussed in this contribution. Kinetic studies on these block copolymerizations as well as characterization studies were performed to investigate the monomer composition in the respective PS and PMA blocks. MALDI-TOF-MS was performed to clarify the exact number of repeating units of each block and the total number of units in the block copolymer. Block copolymers up to 22 kDa could be analyzed by MALDI-TOF-MS, whereby polymers with PMA as first block showed a large second distribution corresponding to PMA homopolymers. However, SEC demonstrated that only a small amount of homopolymer was present indicating that care needs to be taken with interpreting MALDI-TOF-MS data, which is a qualitative rather than a quantitative technique.