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单向函数的存在性是密码学的最基本假设, 也是绝大多数对称密码学算法的充分必要条件. 作为一个计算复杂性问题, 单向函数可以用来构造伪随机产生器进而构成流密码算法, 或是在伪随机产生器的基础上进一步构造伪随机函数和伪随机置换从而用作分组加密算法. 规则单向函数是一类具有特殊结构的单向函数, 该函数的每个像都有相同个数的原像. 基于单向函数的密码学组件(如伪随机产生器)构造研究主要有两种思路: 一是从任意单向函数出发来设计组件, 其优点是具有通用性, 不需要使用单向函数的特有结构; 另一种是从具有特定结构的单向函数(比如单向置换、规则单向函数等)出发来设计组件, 其优点是构造出来的密码学组件效率较高(比如种子长度更短、单向函数调用次数更少等). 学界一直感兴趣于怎样在两者之间取得折中: 即寻找既能够适用于范围更广的单向函数、又具有高效性的构造方法. 本文提出了弱规则单向函数的概念, 规则单向函数仅是弱规则单向函数的一种特殊情况. 如果一个函数不是弱规则函数的话, 那么这种反例的构造需要人工刻意设计. 本文进一步通过具体构造说明, 基于规则单向函数的密码学组件构造(伪随机产生器)可以推广至基于弱规则单向函数的情况. 与HILL型产生器相比, 基于弱规则单向函数的伪随机产生器构造兼具种子长度更短和保持安全性的优点. 基于弱规则单向函数的通用单向哈希函数构造则推广了学界基于未知规则单向函数构造的研究工作, 具有密钥长度为O(nlogn)、输出长度为的特点.

In Chinese, the three high frequency adverbs ji, bian, and jiu, are often discussed together, since they can all function as consecutive adverbs and temporal adverbs indicating ‘immediate, right away’. Most scholars agree that the two functions of these adverbs are evolutionally related, but which function emerged earlier is still in debate. This paper is going to study the formation of the temporal function of ji, bian, and jiu, and argue that the three words were undergoing the following grammaticalization: {verbs ＞ consecutive adverbs ＞ temporal adverbs}, a sequence contrary to common opinion. Based on thorough historical investigation, the paper will specify the period when each adverbial function of the three words emerged and also indicate that all three of the changes from consecutive to temporal adverb are triggered by four usages. However, it is still doubtful whether the temporal adverb is less grammaticalized than the consecutive adverb; in other words, whether the path we advocate contradicts the

Quantum private comparison （QPC） aims to accomplish the equality comparison of the secrets from different users without disclosing their genuine contents by using the principles of quantum mechanics. In this paper, we summarize eight modes of quantum state preparation and transmission existing in current QPC protocols first. Then, by using the mode of scattered preparation and one-way convergent transmission, we construct a new multi-user quantum private comparison （MQPC） protocol with two-particle maximally entangled states, which can accomplish arbitrary pair＇s comparison of equality among K users within one execution. Analysis turns out that its output correctness and its security against both the outside attack and the participant attack are guaranteed. The proposed MQPC protocol can be implemented with current technologies. It can be concluded that the mode of scattered preparation and one-way convergent transmission of quantum states is beneficial to designing the MQPC protocol which can accomplish arbitrary pair＇s comparison of equality among K users within one execution.

The aim of this study was to evaluate the effect of controlled intraoral grinding and polishing on the roughness of full-contour zirconia compared to classical veneered zirconia. Thirty bar-shaped zirconia specimens were fabricated and divided into two groups（n515）. Fifteen specimens（group 1） were glazed and 15 specimens（group 2） were veneered with feldspathic ceramic and then glazed. Prior to grinding,maximum roughness depth（Rmax） values were measured using a profilometer, 5 times per specimen. Simulated clinical grinding and polishing were performed on the specimens under water coolant for 15 s and 2 N pressure. For grinding, NTI diamonds burs with grain sizes of 20 mm, 10 mm, and 7.5 mm were used sequentially. The ground surfaces were polished using NTI kits with coarse, medium and fine polishers. After each step, Rmaxvalues were determined. Differences between groups were examined using one-way analysis of variance（ANOVA）. The roughness of group 1 was significantly lower than that of group 2. The roughness increased significantly after coarse grinding in both groups. The results after glazing were similar to those obtained after fine grinding for non-veneered zirconia. However, fine-ground veneered zirconia had significantly higher roughness than venerred, glazed zirconia. No significant difference was found between fine-polished and glazed zirconia, but after the fine polishing of veneered zirconia, the roughness was significantly higher than after glazing.It can be concluded that for full-contour zirconia, fewer defects and lower roughness values resulted after grinding and polishing compared to veneered zirconia. After polishing zirconia, lower roughness values were achieved compared to glazing; more interesting was that the grinding of glazed zirconia using the NTI three-step system could deliver smooth surfaces comparable to untreated glazed zirconia surfaces.

High-temperature （150-220 ℃） growth leads to the formation of some peptide nanotube/microtube （NT/MT） arrays but the NTs/MTs exhibit closed ends, irreversible phase modification and eliminations of piezoelectric and hydrophilic properties. Here we demonstrate the fabrication of unidirectionally aligned and stable diphenylalanine NT/MT arrays with centimeter scale area at room temperature by utilizing an external electric field. The interactions between the applied electric field and dipolar electric field on the NTs and surface positive charges are responsible for the formation. The unidirectionally aligned MT array exhibits a supercapacitance of 1,000 μF·cm^-2 at a scanning rate of 50 mV·s^-1; this is much larger than the values reported previously in peptide NT/MT arrays.

In this study, we investigate pairwise non-classical correlations measured using a one-way quantum deficit as well as quantum coherence in the XY spin-1/2 chain in a transverse magnetic field for both zero and finite temperatures. The analytical and numerical results of our investigations are presented. In the case when the temperature is zero, it is shown that the one-way quantum deficit can characterize quantum phase transitions as well as quantum coherence. We find that these measures have a clear critical point at λ= 1. When λ≤〈 1, the one-way quantum deficit has an analytical expression that coincides with the relative entropy of coherence. We also study an XX model and an Ising chain at the finite temperatures.

In recent years, with the development of quantum cryptography, quantum signature has also made great achievement. However,the effectiveness of all the quantum signature schemes reported in the literature can only be verified by a designated person.Therefore, its wide applications are limited. For solving this problem, a new quantum proxy signature scheme using EPR quantumentanglement state and unitary transformation to generate proxy signature is presented. Proxy signer announces his public key whenhe generates the final signature. According to the property of unitary transformation and quantum one-way function, everyone canverify whether the signature is effective or not by the public key. So the quantum proxy signature scheme in our paper can be publicverified. The quantum key distribution and one-time pad encryption algorithm guarantee the unconditional security of this scheme.Analysis results show that this new scheme satisfies strong non-counterfeit and strong non-disavowal.

An efficient method to compute the permeability of disordered fibrous arrays is pro- posed. A stabilized mixed finite element method is used with an immersed domain ap- proach to represent the porous material at its microscopic scale. Therefore, the Stokes e- quations are solved in the whole domain （including solid part） using a penalization method. The accuracy is controlled by refining the mesh around the fluid-solid interface defined by a level-set function. Using homogenization techniques, the permeability of an RVE is obtained. Furthermore, a new method to generate disordered fibers in function of the porosity, Ф, and other microstructural parameters is proposed and a study of the effect of inter-fiber spacing on K：, the permeability tensor, is performed using parallel computation and over 460 simulations were carried RVEs consisting of over 555 fibers. This task was achieved out in two-dimensional

Unidirectional acoustic transmission has been investigated in an asymmetric bull＇s eye structure, which consistes of a sub- wavelength hole with concentric grooves on one side of a thin steel plate. When acoustic waves impinge normally on the groove side of the asymmetric structure, a strong acoustic transmitted energy flux is observed in the frequency range of 400-450 kHz, while there is no obvious transmitted energy flux in the same frequency range if the acoustic waves impinge normally on the other side. Thus, a remarkable unidirectional acoustic transmission behavior is exhibited by the current struc- ture. With changing the period of the grooves, it is found that the transmitted acoustic energy flux keeps unchanged while the frequency of the transmitted waves can be modified. The experiments are performed, which has confirmed the unidirectional acoustic transmission behavior in the asymmetric bull＇s eye structure. The asymmetric bull＇s eye structure may have potential application in ultrasound diagnosis and therapy.

To develop a novel method predicting the viscoelastic behavior of polymer matrix composites according to the viscoelasticity of the matrix, we used the viscoelastic model of the matrix to build new models for unidirectional composites in both 0° and 90° directions. Viscoelastic parameters for both new models were derived, and the obtained equations shared the same form as the viscoelastic constitutive equation of matrix material. The viscoelastic behaviors of matrix material and unidirectional composites were also tested. Results showed that fitting parameters of creep compliance equation were close to the theoretical values of viscoelastic constitutive parameters of the unidirectional composites, proving the validity of the models. A new method was obtained to predict the viscoelastic property of the unidirectional composites based on the viscoelastic property of composite matrix and elastic property of the unidirectional composites. This method provides a theoretical basis for future studies on the viscoelasticity of composite laminates.