Design of quantum VQ iteration and quantum VQ encoding algorithm taking O（√N） steps for data compression

Vector quantization (VQ) is an important data compression method. The key of the encoding of VQ is to find the closest vector among N vectors for a feature vector. Many classical linear search algorithms take $O(N)$ steps of distance computing between two vectors. The quantum VQ iteration and corresponding quantum VQ encoding algorithm that takes $O(\sqrt N )$ steps are presented in this paper. The unitary operation of distance computing can be performed on a number of vectors simultaneously because the quantum state exists in a superposition of states. The quantum VQ iteration comprises three oracles, by contrast many quantum algorithms have only one oracle, such as Shor's factorization algorithm and Grover's algorithm. Entanglement state is generated and used, by contrast the state in Grover's algorithm is not an entanglement state. The quantum VQ iteration is a rotation over subspace, by contrast the Grover iteration is a rotation over global space. The quantum VQ iteration extends the Grover iteration to the more complex search that requires more oracles. The method of the quantum VQ iteration is universal.     

Enabling Efficient Folding and High-Resolution Crystallographic Analysis of Bracelet Cyclotides

Cyclotides have attracted great interest as drug design scaffolds because of their unique cyclic cystine knotted topology. They are classified into three subfamilies, among which the bracelet subfamily represents the majority and comprises the most bioactive cyclotides, but are the most poorly utilized in drug design applications. A long-standing challenge has been the very low in vitro folding yields of bracelets, hampering efforts to characterize their structures and activities. Herein, we report substantial increases in bracelet folding yields enabled by a single point mutation of residue Ile-11 to Leu or Gly. We applied this discovery to synthesize mirror image enantiomers and used quasi-racemic crystallography to elucidate the first crystal structures of bracelet cyclotides. This study provides a facile strategy to produce bracelet cyclotides, leading to a general method to easily access their atomic resolution structures and providing a basis for development of biotechnological applications.     

Tension–compression asymmetry of phosphor bronze for electronic parts and its effect on bending behavior

In-plane tension and compression experiments on copper alloy sheets (phosphor bronze) and 6000 series aluminum alloy sheets (AA6016-T4) were conducted using a specially designed testing apparatus. The apparatus is equipped with comb-type dies so that stress–strain curves of a sheet specimen subjected to tension followed by compression, and vice versa, can be measured without buckling of the specimen, as well as those for monotonic tension and compression. A difference was observed in the flow stresses between tension and compression for the as-received copper alloy, but not for the aluminum alloy. Moreover, stress reversal tests, such as tension followed by compression and compression followed by tension, were carried out in order to measure the Bauschinger effect. In the second part of the experiment, bending moment–curvature diagrams were measured for the as-received and pre-stretched specimens. The bending moment–curvature diagrams were compared with those calculated using the stress–strain curves obtained from the tension–compression tests, and were in good agreement with those calculated with the tension–compression asymmetry and the Bauschinger effect correctly reproduced.     

对乙酰氨基酚在活化玻碳电极上的电化学行为及测定

应用循环伏安法,研究了对乙酰氨基酚(PCT)在活化玻碳电极上的电化学行为.在pH=4.00的HAc-NaAc缓冲溶液中,PCT的CV扫描于0.54 V左右出现一对明显的氧化-还原峰.电极反应为2电子、2质子的受吸附控制的准可逆过程.其氧化峰电流与PCT浓度在8.00×10-6~2.00×10-4mol.L-1范围内呈良好的线性关系,相关系数r=-0.99918;检出限为6.34×10-6mol.L-1.用于药物样品PCT的含量测定,结果满意.     

主链掺杂氧原子聚硅烷的研究进展

介绍了一类新型有机硅聚合物主链掺杂氧原子聚硅烷的合成与性质.该类聚合物是通过氧原子有规律地插入聚硅烷主链,形成具有氧杂低聚硅烷的序列结构(-[(SiMe2)mO]n-).聚合物的主链呈现了聚硅烷以及聚硅氧烷的杂化体结构.通过对此类聚合物性质的研究,能够获得有关此类聚合物行为的知识,从而进一步促进人们对聚硅烷和聚硅氧烷化学性质的了解.总结了此类聚合物的两类有效合成方法:通过α,ω-二功能基封端的线性硅烷低聚体缩聚反应法以及氧杂环硅烷单体的开环聚合反应法,包括氧杂环硅烷单体的开环聚合平衡和反应机理.讨论了此类聚合物的表征、热稳定性及其结构形态.在结论部分展望了此类聚合物的预期应用前景.     

双官能团醇类化合物催化胺化反应的研究进展

本文综述了由双官能团醇类化合物催化胺化合成二元胺或环胺的研究进展,分别讨论了金属催化剂和固体酸催化剂对双官能团醇类化合物的不同作用机制,考察了反应物结构对 反应活性和选择性的影响,重点介绍了超临界氨流体在二元醇催化胺化反应中的应用,并指出了今后研究的方向.     

外电场作用下三元环状水分子团簇的特性研究

The influence of an external field on the ground states energy and dipole moment of the cyclic water trimer is investigated. Employing the Hartree-Fork method with basis sets 3-21G. The field-induced H-F force including the internal and external forces and clusters equilibrium structures under balance of this force are analyzed. The external field is varied in the 0.001~0.01 a.u. range. It is shown that the magnitude of the external electric field has important effects on these characteristics of the cyclic water trimer. The energy was found to decrease and the dipole moment to increase with the increasing external field. The change of the electronic population of every atom leads the electrostatic field to vary accordingly.     

甲基纤维素(MC)疏水作用的电化学研究

应用电化学循环伏安法, 以电活性小分子亚甲基蓝(MB)为探针, 研究了不同温度下修饰在玻碳电极表面的甲基纤维素(MC)凝胶的疏水性. 研究发现, 在45～70 ℃温度范围内, MB在MC凝胶修饰电极上的式电位E⁰⁽较相应的裸电极均正移, 氧化峰电流i_pa和还原峰电流i_pc分别较相应裸电极增大, 且随温度升高而增大. 这些结果表明MC分子之间发生了疏水相互作用, 且随温度的升高, 疏水作用增强. 此外, 在上述温度下, MC凝胶修饰电极上峰电流的比值i_pc/i_pa均小于1, 为0.70, 且没有观察到MB单独的吸附峰, 因此MB分子在凝胶修饰电极上发生了弱吸附. 本文研究显示电化学方法是研究该类多糖凝胶机理的一个补充手段.     

环酮及其衍生物的光化学反应研究进展

综述了环酮及其衍生物的光化学反应的有机进展.较详细地介绍了单环酮、芳香酮、二元酮和二元环酮的光氧化反应、光还原反应、光偶联反应,尤其是对非增感光氧化反应、潜手性酮的不对称光还原反应以及激光在有机光化学反应中的应用也进行了介绍.     

Enhanced pulse compression induced by the interaction between the third—order dispersion and the cross—phase modulation in birefringent fibres

In this paper,we report on the enhanced pulse compression due to the interaction between the positive third-order dispersion (TOD) and the nonlinear effect (cross-phase modulation effect) in birefringent fibres.Polarization soliton compression along the slow axis can be enhanced in a birefringent fibre with positive third-order dispersion,while the polarization soliton compression along the fast axis can be enhanced in the fibre with negative third-order dispersion.Moreover,there is an optimal third-order dispersion parameter for obtaining the optimal pulse compression.Redshifted initial chirp is helpful to the pulse compression,while blueshifted chirp is detrimental to the pulse compression.There is also an optimal chirp parameter to reach maximum pulse compression.The optimal pulse compression for TOD parameters under different N-order solitons is also found.