折衍混合复消色差望远物镜设计的PWC方法

将衍射结构视为折射率无限大的薄透镜，研究了衍射透镜高折射率表示的折衍混合复消色差望远物镜设计的PWC方法；设计了焦距为2000mm、相对孔径为1/15的双片型折衍混合复消色差望远物镜，并与常规三片型纯折射复消色差望远物镜进行了比较，结果表明双片型折衍混合复消色差望远物镜具有更好的二级光谱校正能力，色球差更小，因此具有更好的成像质量.     

A floating-point genetic algorithm for solving the unit commitment problem

This paper proposes a floating-point genetic algorithm (FPGA) to solve the unit commitment problem (UCP). Based on the characteristics of typical load demand, a floating-point chromosome representation and an encoding–decoding scheme are designed to reduce the complexities in handling the minimum up/down time limits. Strategic parameters of the FPGA are characterized in detail, i.e., the evaluation function and its constraints, population size, operation styles of selection, crossover operation and probability, mutation operation and probability. A dynamic combination scheme of genetic operators is formulated to explore and exploit the FPGA in the non-convex solution space and multimodal objective function. Experiment results show that the FPGA is a more effective technique among the various styles of genetic algorithms, which can be applied to the practical scheduling tasks in utility power systems.     

Taming Gold(I)–Counterion Interplay in the De‐aromatization of Indoles with Allenamides

A careful interplay between the π electrophilicity of a cationic Au^I center and the basicity of the corresponding counterion allowed for the chemo‐ and regioselective inter‐ as well as intramolecular de‐aromatization of 2,3‐disubstituted indoles with allenamides. The silver‐free bifunctional Lewis acid/Brønsted base complex [{2,4‐(tBu)₂C₆H₃O}₃PAuTFA] assisted the formation of a range of densely functionalized indolenines under mild conditions.     

α‐Fe2O3 Cubes with High Visible‐Light‐Activated Photoelectrochemical Activity towards Glucose: Hydrothermal Synthesis Assisted by a Hydrophobic Ionic Liquid

A liquid/liquid interfacial reaction system was designed to fabricate α‐Fe₂O₃ cubes. The reaction system uses a hydrophobic ionic liquid containing iron ions ([(C₈H₁₇)₂(CH₃)₂N]FeCl₄) for manufacturing α‐Fe₂O₃ cubes by a novel and environmentally friendly hydrothermal method under low‐temperature conditions (140 °C). The iron‐containing ionic liquid is hydrophobic and can form a liquid/liquid interface with water, which is vital for fabrication of the α‐Fe₂O₃ cubes. Nanomaterials synthesized from hydrophobic iron‐containing ionic liquids show good crystallinity, well‐developed morphology, and uniform size. The effect of different ionic liquids on the morphology of α‐Fe₂O₃ was investigated in detail. [(C₈H₁₇)₂(CH₃)₂N]FeCl₄ is assumed to perform the triple role of forming a liquid/liquid interface with water and acting as reactant and template at the same time. The effect of the reaction temperature on the formation of the α‐Fe₂O₃ cubes was also studied. Temperatures lower or higher than 140 °C are not conducive to formation of the α‐Fe₂O₃ cubes. Their photoelectrochemical properties were tested by means of the transient photocurrent response of electrodes modified with as‐prepared α‐Fe₂O₃ cubes. The photocurrent response of an α‐Fe₂O₃ cubes/indium tin oxide electrode is high and stable, and it shows great promise as a photoelectrochemical glucose sensor with high sensitivity and fast response, which are beneficial to practical applications of nanosensors.     

Crowding with nearest neighbors replacement for multiple species niching and building blocks preservation in binary multimodal functions optimization

This paper introduces a novel niching scheme called the q-nearest neighbors replacement (q-NNR) method in the framework of the steady-state GAs (SSGAs) for solving binary multimodal optimization problems. A detailed comparison of the main niching approaches are presented first. The niching paradigm and difference of the selection-recombination genetic algorithms (GAs) and the recombination-replacement SSGAs are discussed. Then the q-NNR is developed by adopting special replacement policies based on the SSGAs; a Boltzmann scheme for dynamically sizing the nearest neighbors set is designed to achieve a speed-up and control the proportion of individuals adapted to different niches. Finally, experiments are carried out on a set of test functions characterized by deception, epistasis, symmetry and multimodality. The results are satisfactory and illustrate the effectivity and efficiency of the proposed niching method.     

Novel facile detection of persistent organic pollutants using highly sensitive gas sensor

Persistent organic pollutants (POPs) are greatly noxious chemicals in environment, and they can cumulate in organisms and transfer between different species. Therefore, it is significant to detect POPs for both environmental evaluation and further treatment. However, developing facile approach for the detection of POPs still remains a challenge so far. In this paper, we report an innovative method for facile detection of POPs using gas sensor for the first time. Porous SnO₂ nanostructures with a special tri-walled structure prepared via hydrothermal route and annealing process, were employed as gas-sensing materials. Through gas measurements, it was revealed that the as-fabricated gas sensor exhibited highly sensitive performance towards target POPs, including methoxychlor, mirex, p,p′-DDT, and aldrin. Moreover, we found that target POPs were distinguishable by extracting characteristics in kinetic curves of gas adsorption-desorption. As the presented detecting approach is facile without the requirements of complex operations, expensive and bulky instruments, it is expected that it would be developed as a promising method for the detection of POPs, and thereby showing its significance for environmental monitoring.     

The performance of a fast testing system for illicit materials detection based on energy-dispersive X-ray diffraction technique

A prototype setup for detecting illicit materials by energy-dispersive X-ray diffraction (EDXRD) has been developed. The obtained results of NaCl by the equipment suggest that the total measurement system is reliable and can be used to detect different kinds of materials. The tests of TNT, methamphetamine and heroin are also performed on this equipment and the related EDXRD spectra are obviously influenced by the detecting angle and the X-ray sources. The detecting angle of 10° is more suitable for detecting TNT and methamphetamine, while 12° is better for heroin. Moreover, the curves of TNT, methamphetamine and heroin emitted by W target have more diffraction peaks than those emitted by Cu or Mo target, while the peak intensities of TNT and methamphetamine emitted by Mo are stronger than those emitted by Cu or W target. The curve of methamphetamine emitted by Mo target shows a special characteristic and exhibits a super strong diffraction peak located at 1.62 Å^{− 1}, which can be attributed to the effect arising from Mo kα and kβ.     

MULTIPLE SCATTERING AND DYNAMIC STRESS ANALYSIS OF ELASTIC WAVES IN A FIBER—REINFORCED COMPOSITE WITH INTERFACES

Based on the theory of elastic dynamics, multiple scattering of elastic waves and dynamic stress concentrations in fiber-reinforced composite are studied. The analytical expressions of elastic waves in different regions are presented. The mode coefficients of elastic waves are determined in accordance with the continuous conditions of displacement and stress on the boundary of the multi-interfaces. By using the addition theorem of Hankel functions, the formula of scattered wave fields in different local coordinates are transformed into those in one local coordinate to determine the unknown coefficients and dynamic stress concentration factors (DSCFs). The influences of the distance between two inclusions, material properties and structural size on the DSCFs near the interfaces are analyzed. As examples, the numerical results of DSCFs near the interfaces for two kinds of fiber-reinforced composites are presented and discussed. The project supported by the National Natural Science Foundation of China (19972018)     

A new application of X‐ray scattering using principal component analysis – classification and identification of liquid precursor chemicals

X‐ray scattering (XRS) combined with principal component analysis has been utilized for classifying and identifying liquid precursor chemicals for the first time. The XRS spectra of some liquid precursor chemicals and normal materials were obtained by using an XRS system, and the profiles of scattering media distinctly reveal that the XRS spectra are unique corresponding to the specific liquid material. Furthermore, the obtained spectra were processed through principal component analysis by using the selected energy region in the spectra. The score plots of each substance were clustered together and almost coincident for the same liquid, implying good repeatability and reliability. As far as the different liquid materials are concerned, they could be classified into distinct groups according to their positions in the score plot. The score plots showed a clear classification and recognition of liquid precursor chemicals. This study demonstrates a possibility for analyzing different liquid materials, and it presents a new application for X‐ray spectroscopy. Copyright © 2012 John Wiley & Sons, Ltd.