隐函数求解法在单供气孔静压气体球轴承参数优化中的应用

摈弃不可压缩流简化,在已知承载力的条件下,以最大静刚度为设计准则,建立了显含单供气孔静压气体球轴承3个结构参数和隐含轴承刚度的隐式方程.利用隐函数的导数及矩阵的正定性,讨论了隐函数极值存在的条件.在约束条件中加入了小孔节流器的实现条件、稳定性工作条件及加工制造限制条件等.编制MATLAB程序求解了隐函数极值及其对应的轴承结构参数取值,计算结果与使用不可压缩流简化得到的显式刚度方程的优化参数完全一致.     

Amphiphilic Graft Copolymers of Hydroxypropyl Cellulose Backbone with Nonpolar Polyisobutylene Branches

The novel amphiphilic graft copolymers with hydrophilic hard polar hydroxypropyl cellulose(HPC) backbone and hydrophobic soft nonpolar polyisobutylene(PIB) branches have been successfully synthesized through nucleophilic substitution reaction of living PIB chains carrying oxonium ions with the-OH groups along HPC backbone. The PIB branch length in the graft copolymers could be designed by living cationic polymerization and the grafting density could be adjusted by PIB~+/-OH molar ratio. The living PIB chains carrying oxonium ion were prepared by transformation of allyl bromide end groups in the presence of AgClO_4 and silver nanoparticles(3.2±0.3 nm, 0.7 wt%-1.8 wt%)generated in situ from AgBr. The phase-separation morphology was formed in the graft copolymers due to their incompatibility between backbone and branches. The hydrophilicity on the surface of graft copolymer films could be turned to hydrophobicity by increasing grafting density or/and length of PIB branches. The soft PIB segments in graft copolymers provided an unique surface via self-assembly for anti-protein adsorption against bovine serum albumin. A small amount of Ag nanoparticles in the copolymers contributed to good antibacterial activities against Staphylococcus aureus or Escherichia coli.     

下料问题的优化模型及其快速算法

结合生产实际中具体的下料问题,本文建立了该类问题的优化模型,并提出下料方式的遴选三准则,即高利用率优先准则,长度优先准则和时间优先准则.运用本文的算法对一维下料的利用率高达99.6%,机器时间4秒.对二维的利用率为98.9%,机器时间约7秒.     

一种基于结构性改变的光子晶体光纤光栅理论研究

对一种新型基于结构性改变的光子晶体光纤光栅原理进行了研究.采用多极法分析了结构性改变对折射率的影响,得到有效折射率与包层气孔塌缩之间的关系,建立了结构性改变光子晶体光纤光栅模型.利用耦合模理论对所成光栅性能进行了分析,重点研究了包层空气孔层数、空气孔占空比、气孔塌缩程度对光栅谐振波长、带宽的影响.研究结果表明,光子晶体...     

Cross-linked starch nanoparticles stabilized Pickering emulsion polymerization of styrene in w/o/w system

Here, we present a method to synthesize expandable spherical polystyrene beads containing well-dispersed water microdroplets. The beads, 2–3 mm in diameter, were prepared through surfactant-free Pickering emulsion polymerization in water-in-oil-in-water (w/o/w) system using cross-linked starch nanoparticles (CSTN) as emulsifier. The CSTNs were in situ surface-modified by styrene maleic anhydride copolymer as confirmed by infrared spectroscopy and contact angle analysis. The entrapped water microdroplets with the average size of 3–4 μm were shown to be surrounded by a dense layer of the CSTN. The number droplet density as well as water encapsulation efficiency in the polystyrene beads increased with the CSTN concentration. Furthermore, regardless of CSTN content, all samples exhibited high encapsulation stability of over 68 % after 3 months. These characteristics along with good expansion behavior suggest the synthesized beads as expandable polystyrene containing water as a green blowing agent.     

Si doping effect on self-organized InAs/GaAs quantum dots

In situ ultra high vacuum scanning probe microscopy (SPM) and low-temperature photoluminescence (PL) studies have been performed on Si-doped self-organized InAs/GaAs quantum dots samples to investigate the Si doping effects. Remarkably, when Si is doped in the sample, according to the SPM images, more small dots are formed when compared with images from undoped samples. On the PL spectra, high-energy band tail which correspond to the small dots appear, with increasing doping concentration, the integral intensity of the high-energy band tail account for the whole peak increase too. We relate this phenomenon to a model that takes the Si atom as the nucleation center for QDs formation.     

Insulin-binding aptamer-conjugated graphene oxide for insulin detection

This paper describes a simple and sensitive aptamer/graphene oxide (GO) based assay for insulin detection. GO can protect DNA from nuclease cleavage, but aptamers can be detached from the GO surface by specific target binding. This exposes the aptamers to enzymatic cleavage and releases the target for a new cycle. Cycling of targets leads to significant signal amplification and low LOD.     

一氧化碳/苯乙烯共聚催化体系的优化

用醋酸钯,１,１０－邻菲咯啉,对甲苯磺酸,对苯二醌和甲醇组成的催化体系进行了一氧化碳／苯乙烯共聚反应,成功地制得了一氧化碳和苯乙烯的线性交替共聚物－聚酮（ＳＴＣＯ０,在催化体系组成的筛选过程中,对人工神经网络的应用进行了探索性研究。首先,采用ＶｉｓｕａｌＣ＋＋１．５２编制了ＢＰ神经网络,利用正交实验结果对该神经网络进行了训练,训练误差小于５％。     

级配碎石弹性模量的动三轴试验研究

通过室内动三轴试验，提出了级配碎石弹性模量随应力状态而变化的非线性模型，分析了含水量和密实度对弹性模量的影响，最后提出常应力状态下级配碎石弹性模量建议值。     

LiNbO3∶Cr∶Cu晶体吸收特性及非挥发全息存储研究

研究了LiNbO3∶Cr∶Cu晶体的吸收特性,发现LiNbO3∶Cr∶Cu（含0.14 wt.% Cr2O3 和 0.011 wt.% CuO）晶体存在两个明显的吸收峰,中心波长分别位于480 nm和660 nm; 随着Cr的含量逐渐减小,Cu的含量逐渐增大,短波段不存在明显吸收峰,掺Cr的含量越大,中心波长在660 nm处的吸收越大；633 nm红光虽然位于中心波长为660 nm的吸收峰内,但它无助于光折变过程.分别采用390 nm紫外光和488 nm蓝光作为敏化光,514 nm绿光作为记录光的记录方案,实现了非挥发全息记录,掺入适量的Cr( 比如NCr=2.795×1025 m－3,NCr/ NCu=1)有助于全息记录性能的提高.