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Self-assembly of lamella-forming diblock copolymers confined in nanochannels: Effect of confinement geometry 下载免费PDF全文
The self-assembly of symmetric diblock copolymers confined in the channels of variously shaped cross sections(regular triangles, squares, and ellipses) is investigated using a simulated annealing technique. In the bulk, the studied symmetric diblock copolymers form a lamellar structure with period LL. The geometry and surface property of the confining channels have a large effect on the self-assembled structures and the orientation of the lamellar structures. Stacked perpendicular lamellae with period LLare observed for neutral surfaces regardless of the channel shape and size, but each lamella is in the shape of the corresponding channel’s cross section. In the case of triangle-shaped cross sections, stacked parallel lamellae are the majority morphologies for weakly selective surfaces, while morphologies including a triangular-prism-shaped B-cylinder and multiple tridentate lamellae are obtained for strongly selective surfaces. In the cases of square-shaped and ellipse-shaped cross sections, concentric lamellae are the signature morphology for strongly selective surfaces, whereas for weakly selective surfaces, stacked parallel lamellae, and several types of folding lamellae are obtained in the case of square-shaped cross sections, and stacked parallel lamellae are the majority morphologies in the case of ellipse-shaped cross sections when the length of the minor axis is commensurate with the bulk lamellar period. The mean-square endto-end distance, the average contact number between different species and the surface concentration of the A-monomers are computed to elucidate the mechanisms of the formation of the different morphologies. It is found that the resulting morphology is a consequence of competition among the chain stretching, interfacial energy, and surface energy. Our results suggest that the self-assembled morphology and the orientation of lamellae can be manipulated by the shape, the size, and the surface property of the confining channels. 相似文献
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本文描述了一自带缓存的数据采集系统,并将本系统所采用的技术与通用的数据采集系统作了比较,最后提出了本系统作进一步升级的方法 相似文献
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淀粉是烟草中较难测定的成分之一.为了快速准确地测定烟草中的淀粉含量,研究了高氯酸萃取-连续流动法测定烟样中淀粉含量的方法,即每0.1g烟草样品用1.0mL 50%的乙醇和1.2mL 72%高氯酸萃取烟草样品中的淀粉,通过自动化学分析仪(滤光片波长660nm)测定淀粉含量.采用本法测定了云南烤烟烟叶、杀青烟叶、白肋烟和香料烟的淀粉含量,平均回收率为96.71%,相对标准偏差在1.79%-5.58%之间.与传统的酸解法和酶解法比较,本法操作步骤简单、检测成本低、快速准确. 相似文献
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烟草中的水溶性总糖主要为葡萄糖、果糖、蔗糖,是烟叶内重要的碳水化合物,本文研究了用超声波提取,离子色谱法同时检测烟草中水溶糖的分析方法。采用美国Dionex公司DX-500型离子色谱仪,用H2O和200 mmol/LNaOH淋洗,流速为0.8 mL/min,脉冲安培检测器成功地测定了烟草中的葡萄糖、果糖和蔗糖等成份的含量。各成份在检测条件下有很好的线性,决定系数r2>0.99,检出限范围葡萄糖、果糖为2~50 mg/L,蔗糖为1~25 mg/L,相对标准偏差为1.12%~2.62%,回收率为91.2%~103.3%;实验表明该方法具有分析时间短、线性范围宽、灵敏和准确、简单快速、试剂用量少等优点。 相似文献
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膏溶角砾岩侧限膨胀特性试验研究 总被引:1,自引:0,他引:1
研究了膏溶角砾岩的侧限膨胀特性及其影响因素。这种岩石受到扰动后可吸水发生膨胀变形使其结构发生变形甚至破坏。通过GDG高压固结仪采用平衡加压法和充分膨胀法研究了侧限情况下岩石的膨胀力指标, 解释了充分膨胀法膨胀力指标大于平衡加压法膨胀力指标的原因。通过试验研究了供水充足条件下膏溶角砾岩侧限自由膨胀变形演化规律, 阐述了膏溶角砾岩侧限膨胀变形的影响因素。岩石试样采自山西石太客运专线太行山隧道, 试验结果表明, 膏溶角砾岩的膨胀特性不同于常规的膨胀岩, 其轴向膨胀变形随含水率增加而增加, 随密度增大而减小。 相似文献
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近红外光谱法快速检测烟草中部分香气物的应用研究 总被引:6,自引:0,他引:6
应用傅立叶变换近红外漫反射光谱仪,从500个样品中按高、中、低含量挑选出具代表性的150~172个烟草样品建立了近红外光谱与烟草中的苹果酸、柠檬酸和石油醚提取物成分含量间的数学模型,用建立的模型对36个样品进行预测,结果表明,各成分近红外预测值与实测值之间的平均偏差:苹果酸为0.090,柠檬酸为0.040,石油醚提取物为0.124;且近红外预测值与化学法不存在显著性差异,近红外光谱分析技术可初步用于烟草部分香气成分的快速定量分析. 相似文献
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本文利用基于最小模型误差法和线性不连续跳跃多重打靶法基础上建立的非线性只法,辨识飞机起飞着陆过程飞机的非线性动态模型。对于包含复杂非线性项的动态系统,本方法可以从实际试验量测的系统非线性数据,确定飞机处于地面效应影响运动过程的系统模型,而不需要预先详细描述系统的非线性形式。 相似文献