优化方法和最优控制在力标准机控制系统中的应用

新建5 MN液压式力标准机时,对于液压式力标准机力值砝码加卸载系统提出了新方案,利用最优控制技术进行力值砝码加卸载系统的设计,从而大大提高力标准机的工作效率。     

嵌入式系统在液压式力标准机控制系统中的应用

新建5 MN液压式力标准机时,设计了液压式力标准机的力值砝码加卸载系统。利用嵌入式系统控制力值砝码加卸载系统,从而满足了对力传感器或标准测力仪的特殊检测要求,提高了力标准机的工作效率。     

静重式力标准机砝码交换力平衡控制技术

静重式力标准机利用少量的砝码，进行相等力值间隔逐级加、卸荷时，需要交换砝码。当砝码进行交换时出现逆负荷现象，会对被检测力仪的示值产生影响。阐述了静重式力标准机采用的交换砝码方法是建立在利用弹性力替代砝码重力，砝码交换过程中重力与弹性力达到平衡的基本原理。提出了实现静重式力标准机砝码交换时系统达到力平衡的一种预加荷装置，经砝码交换力平衡控制的力学分析与实验验证，静重式力标准机采用预加负荷实施倒码力平衡控制的方法在理论上和技术上是可行的、有效的。     

5MN液压式力标准机的设计与验证

设计开发了一种液压式力标准机,对其不确定度进行了评定,并对其测量性能进行了验证。在传统液压式力标准机的基础上,设计了一种新型静压油缸系统,消除了初载荷对测量结果的影响,提高了测量准确度。开发了一套力值砝码加卸载系统,实现了更加高效的加卸载。经中国计量科学院现场检定,所开发的力标准机达到JJG 1117—2015《液压式力标准机检定规程》0.05级的要求。     

杠杆式力标准机控制系统设计

力标准机是力学计量中对各种力传感器、测力仪和称重传感器进行检定或测试的设备,它通常分为静重式、杠杆式、液压式、叠加式等类型。力值不确定度主要取决于砝码质量的不确定度、安装地点重力加速度的测量不确定度、砝码和空气密度的测量不确定度,同时还与砝码的稳定性、加卸方式及机器的结构有关。本文提出了一种杠杆式力标准机电气控制系统的设计方案,     

静重式力标准机砝码在线称量方法的研究

本文介绍了一种在线称量静重式力标准机砝码的方法,该方法通过设计一种新的静重式力标准机砝码现场称量装置,可在不拆卸砝码的情况下,完成静重式力标准机砝码的称量.     

JJG1116-2015《叠加式力标准机检定规程》解读

正JJG753-1991《叠加式力标准机检定规程》于1991年颁布。2001年,出于精简规程数量的要求,叠加式、液压式、静重式、杠杆式四类力标准机合并入JJG734-2001《力标准机检定规程》,并一直执行至今。叠加式力标准机(以下简称"叠加机")使用力传感器复现力值,其他类力标准机使用砝码复现力值,     

关于力标准机量值长期稳定性及某些标准机结构配置中存在缺陷的研究

<正>一、现力值的测量不确定度影响因素按照结构分析可以得出各类型力标准机的主要不确定度影响因素以及影响的途径和程度。静重式力标准机的主要影响因素包括砝码质量、重力加速度、空气密度、砝码密度等参数的测量不确定度,同时还受工作台水平度(或拉头同轴度)、砝码摆动量等的影响。杠杆式力标准机的主要影响因素除静重式力标准机的影响因素之外,还包括杠杆放大比、杠杆灵敏阈等的影响。液压式力标准机的主要影响因素除静重式力标     

液压式力标准机改造

一、概述针对旧式液压式力标准机,我所依据改造技术要求制定技术方案并实施改造工程。换装新型先进液压伺服控制系统,改造砝码加卸装置,研制先进的电控系统。运用神经元控制技术,实现机器工作的精确力值施加和高稳定度控制;以伺服驱动、数字控制技术为主要技术手段,实施重力砝码的高效、准确加卸;以计算机为主控制器,以高性能激光位置传感器     

JJG1117-2015《液压式力标准机检定规程》解读

正JJG734-2001《力标准机检定规程》包含静重式、杠杆式、液压式和叠加式4种力标准机。这4种力标准机的结构和原理不尽相同,计量性能要求、检定项目和检定方法也有不同,其中对不同类型的力标准机的检定方法缺少针对性,在执行过程中容易引起误解和争议。单独制定JJG1117-2015《液压式力标准机检定规程》,将有关液压式力标准机的内容从JJG734-2001中分离出来并加以完善,有利于液压式力标准机检定     

Half-Metallic Ferromagnetism in New Half-Heusler Compounds: an Ab Initio Study of CrTiX (X = Si,Ge, Sn,Pb)

In this work, half-metallic (HM) properties of new Half-Heusler (HH) ferromagnetic compounds CrTiX (X = Si, Ge, Sn, Pb) are studied by means of first principle band structure calculation within the framework of density functional theory (DFT). From the spin-polarized calculations using full-potential linearized augmented plane-wave (FP-LAPW)method, we found that all of these compounds are stable in ferromagnetic MgAgAs-type crystal structure. The latticeparameters of CrTiX compounds increase with increasing atomic radius of X atom and ranges from 5.76 to 6.38 Å. The calculated electronic structure of these compounds in MgAgAs-type structure shows that they are HM materials with an integer magnetic moment of 4 μ _B. Densities of states, electronic band structure, and origin of ferromagnetism have been discussed, and robust HM nature of these compounds is analyzed which makes them fascinating compounds for spintronic devices.     

整体油箱防腐蚀-密封保护工艺研究

根据飞机整体油箱金属构件被腐蚀和聚硫密封剂功能下降造成整体油箱渗漏的原因,研究了采用新型防腐底漆Ｈ０６－１０１２Ｈ和整体油箱内表面保护密封斜料ＨＭ５０１相配合对整体油箱金属部件及聚硫密封剂层进行防腐蚀保护和防老化保护施工工艺参数,取得了良好工艺效果。     

Harmine-loaded galactosylated pluronic F68-gelucire 44/14 mixed micelles for liver targeting

Harmine (HM), a phytoconstituent has wide range of pharmacological activities including antimicrobial, antifungal, antioxidative, and anticancer. HM has shown promising anticancer activity against liver cancer cells. However, poor aqueous solubility, multidrug pump P-gp efflux, extensive in vivo metabolism, and rapid elimination due to glucuronidation/sulfation limit clinical utility of HM. In order to overcome the drawbacks of HM, the current work reports preparation of HM-loaded galactosylated pluronic F-68 (PF68)-Gelucire^® 44/14 (GL44) mixed micelles (HM-MM). 3² factorial design was used to investigate the effect of formulation variables on formation HM-loaded mixed micelles. Solvent evaporation method was used for preparation of HM-MM. The optimized HM-MM was evaluated for size, percent drug entrapped (EE), in vitro HM release, oral bioavailability, and biodistribution in rats. HM-MM with an average size 277.5?±?3.24?nm had an EE of 86.5?±?1.51% w/w. HM-MM released HM in a controlled manner. Additionally, HM-MM showed significant enhancement in oral bioavailability (around six-folds) of HM when compared to HM alone. Further, HM-MM showed around sevenfold higher amount of HM in the liver when compared to HM alone revealing efficient drug targeting capability. Such significant improvement in oral bioavailability of HM when formulated into mixed micelles could be attributed to solubilization of hydrophobic HM into micellar core along with P-gp inhibition effect of both galactosylated PF68 and GL44. Thus, the present work highlights galactosylated PF68 and GL44 mixed micelles as an efficient carrier system having drug targeting capability and potential to enhance bioavailability of BCS class II drugs.     

Development of an inverse method to identify the kinetics of heavy metal release during waste incineration in fluidized bed

This paper deals with the emission of heavy metals (HM) during the incineration of municipal solid waste in a fluidized bed reactor. This study focused on the development of a general method to identify the kinetics of vaporization of heavy metals from the on-line analysis of exhaust gas. This method is an inverse method, which requires only the time evolution of the HM concentration in exhaust gases (experimental data) and a global bubbling bed model developed for transient conditions at the reactor scale. First, a lab-scale fluidized bed incinerator was set-up to simulate the HM release during the thermal treatment of metal-spiked model wastes. A specific on-line analysis system based on ICP-OES was developed to measure in real time the variation of the relative concentration of HM in exhaust gases. Then, a two-phase flow bubbling bed model was developed and validated to calculate the kinetics of vaporization of HM from its measured concentration time profile in the outlet gas. The technique was first validated with model waste (metal-spiked mineral matrices), thus enabling at each time both solid sampling for measuring the HM vaporization kinetic and on-line analysis for measuring the HM concentration in the outlet gas. The inverse method was then applied to realistic artificial wastes (derived from real wastes) to identify the HM vaporization kinetics from the on-line analysis results.     

精密喷射成形HM1钢摩擦磨损性能研究

为了探索提高HM1钢耐磨性能的制备新途径,采用往复式滑动干摩擦实验研究了精密喷射成形HM1钢摩擦磨损性能并对其磨损机制进行了分析,同时还与铸态材料进行了对比.结果表明:不同载荷下,喷射态和喷射回火态HM1钢摩擦系数均低于铸态;当载荷为100 N时,与铸态相比,喷射态磨损量比其低约34%,喷射回火态磨损量比其减少约48%.对磨痕形貌分析表明,当载荷为40 N时,铸态试样以粘着磨损为主,当载荷为100 N时,转换为粘着磨损与磨粒磨损共存,并伴随严重的氧化磨损;对于喷射态和喷射回火态试样,则以磨粒磨损为主,氧化磨损减轻.     

Optical force stamping lithography

Here we introduce a new paradigm of far-field optical lithography, optical force stamping lithography. The approach employs optical forces exerted by a spatially modulated light field on colloidal nanoparticles to rapidly stamp large arbitrary patterns comprised of single nanoparticles onto a substrate with a single-nanoparticle positioning accuracy well beyond the diffraction limit. Because the process is all-optical, the stamping pattern can be changed almost instantly and there is no constraint on the type of nanoparticle or substrates used.     

负折射现象的研究进展

负折射现象是一种崭新的现象,是上个世纪60年代理论预言,直到一年前被实验证明微波照射在左手化媒质(LHM)上,折射方向不同于Snell定律所描述的.介绍了这种负折射现象研究的最新发展.着重于LHM的人工合成,理论解释以及负折射率的实验证明等几个方面,以便进一步开展这方面的工作.     

Experimental platform to study heavy metal ion-enzyme interactions and amperometric inhibitive assay of Ag+ based on solution state and immobilized glucose oxidase

The heavy metal (HM) ion-enzyme interaction is an important research topic in many areas. Using glucose oxidase (GOx) as an example, a comprehensive experimental platform based on quartz crystal microbalance and electroanalysis techniques is developed here to quantitatively study the HM ion-enzyme interactions and amperometric inhibitive assays of HM ions. The effects of some common HM ions on the bioactivities of solution-state GOx (GOx(s)), electrode surface-adsorbed GOx (GOx(ads)), and polymer-entrapped GOx (GOx(e)) are comparatively examined on the basis of anodic amperometric detection of enzymatically generated H(2)O(2). Ag(+) shows the strongest inhibition effect among the HM ions examined, and the inhibitive assays of Ag(+) based on GOx(s), GOx(ads), and GOx(e) entrapped in poly(l-noradrenalin) (PNA) give limits of detection (LOD) of 2.0, 8.0, and 5.0 nM (S/N = 3), respectively. Inhibition effects of Hg(2+), Cu(2+), and Co(2+) are detectable only at 15 μM or higher concentrations, and the other HM ions show undetectable inhibition even at 1.0 mM. The developed experimental platform allows one to quantify the number of the bound HM ions per GOx(ads) molecule at various inhibition percentages. In addition, the electrosynthesized PNA matrix to entrap GOx for an inhibitive assay of Ag(+) shows the lowest competitive affinity to HM ions and gives the highest sensitivity, as compared with several other polymer matrixes commonly used for the inhibitive assay. The suggested experimental platform is recommended for wide applications in enzymatic inhibitive assays and quantitative studies of the inhibition effects of HM ions on many other redox-event-relevant enzymes.     

An efficient decision-making framework for hybrid metamodelling

In engineering design optimization, the usage of hybrid metamodels (HMs) can take full advantage of the individual metamodels, and improve robustness of the predictions by reducing the impact of a poor metamodel. When there are plenty of candidates, it is difficult to make decisions on which metamodels to choose before building an HM. The decisions should simultaneously take into account of the number, accuracy and diversity of the selected metamodels. To address this problem, this research developed an efficient decision-making framework based on partial least squares for metamodel screening. A new significance index is firstly derived from the view of fitting error in a regression model. Then, a desirable metamodel combination which consist of only the significant ones is subsequently configured for further constructing the final HM. The effectiveness of the proposed framework is demonstrated through several benchmark problems.     

Effects of film forming and hydrophobic properties of starches on surface sized packaging paper

The effect on mechanical and barrier properties upon addition of glycerol to temperature‐responsive hydrophobically modified (HM) potato starch was studied on free films. The addition of glycerol lowered the glass transition temperature, the storage modulus, and the water vapor permeability (WVP) for the HM starch films. The HM starch phase separates upon cooling below an upper critical temperature into a solid and a liquid phase. Adding glycerol to the warm starch solution had an inhibiting effect on the particulate precipitation. Substrates surface sized with HM starch with various amounts of glycerol were investigated with respect to barrier properties; WVP, contact angle and Cobb values. Hydroxypropylated starch was used as a reference. Cobb values and WVP results on surface‐sized substrates indicated that the film formation properties of the starches were of great importance for the final surface properties. Good film formation properties were essential for the gas barrier and water resistance while they were less important for high contact angles. The WVP decreased as the glycerol content of the sizes increased, but no sufficient water vapor barrier could be obtained. The HM starches investigated in this work provided good oxygen barrier and the contact angles indicated a hydrophobic character of the surface. The role of the precipitate was investigated, and surface sizing with the precipitate gave low WVP and high contact angles despite its poor film‐forming properties under the experimental conditions. Cobb60 values were slightly improved for HM starch with increasing glycerol content over glycerol‐free sizing. Copyright © 2007 John Wiley & Sons, Ltd.