Effects of bottom profile on the circulation and classification of particles in cylindrical hydrocyclones

The cylindrical hydrocyclone has been increasingly used in coarse classification due to its reduced fine particle entrainment, but the loss of coarse particles to overflow remains an intractable problem. Based on the notion that the strong circulation flow caused by the flat bottom structure bears primary responsibility for the problem, this study designs eight unique bottom profiles to regulate the particle circulating flow and attempts to correlate particle circulation flow with classification performance. The effects of the bottom profile on flow field characteristics, particle spatial distribution, circulation flow rates, and grade efficiency are explored in detail using validated models in a Φ200 mm cylindrical hydrocyclone. The findings suggest that bottom profiles have the greatest effect on the axial velocity near the bottom and the grade efficiency of intermediate and coarse particles, while all unique designs have the potential to lower turbulence intensity. An ascending segment near the wall or a descending segment near the axis can help to mitigate the misplacement of coarse particles by reducing particle circulation flow without affecting the entrainment of fines appreciably. Additionally, two circles are found on each side of the cut plane, which is conducive to releasing coarse particles from the circulation flow. Regulation of particle circulation flow by adjusting bottom profile parameters can improve separation performance.     

Ring signature scheme based on multivariate public key cryptosystems

The ring signature scheme is an important cryptographic primitive that enables a user to sign a message on behalf of a group in authentic and anonymous way, i.e. the recipient of the message is convinced that the message is valid and it comes from one of the group members, but does not know who the actual signer is. Currently, all the existing ring signatures are based on traditional cryptosystems. However, the rapid advances in the field of quantum computing indicate a growing threat to traditional cryptosystems. Multivariate public key cryptosystems (MPKCs) is one of the promising alternatives which may resist future quantum computing attacks. In this work, we propose a novel ring signature scheme based on multivariate polynomials with the security model for the first time. Our ring signature scheme has a great advantage in efficiency compared to many existing ring signature schemes, and currently it seems to be immune to quantum computing attacks.     

NEMS diaphragm sensors integrated with triple-nano-ring resonator

Two types of circular diaphragm, made by Si and Si/SiO₂, integrated with hexagonal photonic crystal (PhC) lattice with triple-nano-ring (TNR) resonator created at the centre are proposed as nano-scale force and pressure sensor. The optimized channel drop effect of the TNR resonator brings a strong forward drop resonant peak in both the cases and with Q-factor of 1602 and 1737, respectively. The resonant wavelength peak experience red shifts upon the applied load on the circular diaphragm along the normal direction, in terms of a 2nd-order polynomial relationship. The devices can detect a wide range of applied load. Si diaphragm based micro force sensor gives minimum detectable force of 0.847 μN in the region of applied force from 10 to 20 μN. Si/SiO₂ diaphragm based pressure sensor gives minimum detectable pressure of 4.17 MPa in the region of applied pressure from 20 to 40 MPa. From the derived wavelength shift versus a given centre displacement of the diaphragm, Si diaphragm based sensor shows higher sensitivity than Si/SiO₂ diaphragm sensor.     

An efficient and provable secure identity-based ring signcryption scheme

ID-based ring signcryption schemes (IDRSC) are usually derived from bilinear parings, a powerful but computationally expensive primitive. The number of paring computations of all existing ID-based ring signcryption schemes from bilinear pairings grows linearly with group size, which makes the efficiency of ID-based schemes over traditional schemes questionable. This paper presents a new identity-based ring signcryption scheme, which only takes four pairing operations for any group size and the scheme is proven to be indistinguishable against adaptive chosen ciphertext ring attacks (IND-IDRSC-CCA2) and existentially unforgeable against adaptive chosen message and identity attacks (EUF-IDRSC-ACMA) under the random oracle model.     

Properties of variations in the periods of ring neural oscillators with noise

Effects of additive noise on a series of the periods of oscillations in unidirectionally coupled ring neural networks of ring oscillator type are studied. Kinematical models of the traveling waves of an inconsistency, i.e. the successive same signs in the states of adjacent neurons in the network, are derived. A series of the half periods in the network of N neuron is then expressed by the sum of N sequences of the N-first order autoregressive process, the process with the spectrum of exponential type and the first-order autoregressive process. Noise and the interaction of the inconsistency cause characteristic positive correlations in a series of the half periods of the oscillations. Further, an experiment on an analog circuit of the ring neural oscillator was done and it is shown that correlations in the obtained periods of the oscillations agree with the derived three expressions.     

西门子S7系列PLC在成都地铁BAS系统中的应用

本系统以西门子S7-414H冗余控制器为主站,多台S7—200PLC和S7—300PLC为从站,通过光纤链路模块OLM组成冗余光纤环网,实现地铁设备监控系统的完美控制。文章重点介绍了控制工艺背景、主／从网络组成构架、硬件配置及软件编程．要点、系统中包含的PROFIBUS-DP、MODBUS、网络读写等通讯协议出现的问题及解决方法、调试后达到的效果及应用体会。     

多降液管结晶罐的循环比的确定

结晶罐的循环比是否合理,反映了结晶罐结构性能的优劣。本文通过对糖膏在结晶罐中流动的压力降的分析,讨论了多降液管结晶罐的循环比的理论计算,并提出了等比例的校正方法,使整个计算过程变得非常简单。     

基于RPR的高生存性网络

弹性分组环(RPR)技术定义了一种新型的媒体接入控制(MAC)层协议,采用了共享介质传输和空间复用协议以及低于50 ms的故障恢复保护的弹性机制,支持服务等级协定(SLA,Service Level Agreement),即插即用,基于MAC的高速交换,可承载具有突发性的IP业务,同时支持传统的语音传送,是未来城域网技术的重要发展方向.光纤技术的飞速发展使得RPR不再仅仅局限于城域网,还可以用于广域网.文章在基于RPR的低于50 ms的故障恢复保护的基础上,提出了具有高生存性的解决方案.     

基于双线性对的环签名方案

目前双线性映射作为一种构建密码体制的新工具,在密码学领域中引起了普遍的关注,并在数字签名中得到应用。而环签名因没有群管理员、没有加入和撤出群体过程,签名者只要随机选择若干签名人,利用自己私钥和其他人的公钥进行签名,环签名方案在保护签名人身份不泄露情况下非常有用。利用双线性映射的特性介绍了一个数字签名方案,并在此基础上提出一个新的环签名方案,并对其安全性进行了分析。     

基于身份和双线性对的代理环签名方案

本文提出了一种基于身份和双线性对的代理环签名方案,该方案能够有效地防止授权人冒充代理签名者对消息进行签名,从而代理人的利益得到了很好的保护。它综合了代理签名和环签名的优点,通过引入双线性对节省了计算开销,提高了方案的执行效率。与Zhang提出的代理环签名方案相比,我们的方案将签名验证过程中所需的双线性对计算量由O(n)降低到O(1),计算效率更高。此外,本方案还提供了不可否认服务,较好地满足了代理环签名的安全需求。