中学实验教学改分散为集中用于教学也服务于社会的设想

本文认为要提高我国科技力水平,必须进行中学实验教学改革,提出了将中学实验教学改分散为集中,建立专门的实验基地．用于教学也服务于社会的改革设想。文章从目前我国中学实验教学的现状和弊端．改革设想实施后的意义,改革设想实施应具备的条件以及建立实验基地的前景等几个方面支持了自己的观点。     

国内高校操作系统课程实验教学实施情况评述

本文分析了操作系统课程实验的特点,归纳评述了国内各高校操作系统课程实验的具体实施方法,并提出了解决操作系统课程实验困难的一些设想。     

应用型本科《操作系统》实验教学的研究与实践

本文分析了操作系统课程实验的特点,归纳评述了国内各高校操作系统课程实验的具体实施方法,提出了应用型本科操作系统实验教学一些设想,并对实验项目的设置做了有益的探讨.     

高等农业院校微生物学实验教学改革初探

就微生物学实验教学的实验内容、实验顺序，微生物实验课设置，微生物实验考核办法以及应用现代化教学手段，改进实验教学，提高实验效果等方面的改革作了介绍和总结，并对今后改革的方向提出了设想。     

对《电子线路实验》课程教学改革的思考

本文结合教学工作实际,主要就《电子线路实验》课教学如何培养学员的实际动手能力问题进行了认真研究。提出了《电子线路实验》课教学改革的基本设想。它对于搞好《电子线路实验》教学,具有一定的借鉴意义。     

非物理专业大学物理实验课应对教育创新挑战的研究

通过对近几年我校非物理专业本科学生大学物理实验课学习兴趣的详细调查,发现学生对传统物理实验的兴趣明显下滑,而对半定量和定性实验、计算机仿真实验等表现出很高的学习积极性。对非物理专业物理实验课兴趣培养作了一些尝试,提出了一些新的教学改革设想。     

网络实验室实验教学改革与方案设计

本文主要分析了计算机网络实验的现状和存在的问题，提出计算机网络实验改革的初步设想。通过建立完善的计算机网络实践教学环境，制定科学合理的实验计划，开设与课堂教学相辅相成的实验课，给学生创造实践的机会，培养学生的动手能力，塑造他们的创新精神。     

虚拟仪器方法在电子实验教学中的应用研究

虚拟仪器技术近年来在电子技术实验教学中初露端倪.通过分析虚拟仪器技术的内涵,提出了建立以虚拟仪器为基础的实验系统的设想,对虚拟仪器在电子技术实验教学中的应用进行了规划.     

未来交通工具—“地下飞机”

最近,日本政府综合了建筑业和流体研究学会在5年前就开始研究及实验的一项设想,提出利用地下隧道,以时速600公里的地下飞机往来于各大都市之间。根据设想,地下飞机的机身全长50米,高4米,宽2.4米,呈流线型;机身前后都设有机翼,机翼为长方     

浅谈仪器分析实验教学改革的思路和设想

仪器分析实验是化学实验的重要组成部分,在化工、水产、食品、制药、地质等方面应用广泛,有着举足轻重的作用,越来越引起人们的重视。针对仪器分析实验课的教学特点,本着提高教学质量,培养应用型人才的目的,阐述了在仪器分析实验中的教学改革思路和设想。     

Flow characterization of electroconvective micromixer with a nanoporous polymer membrane in-situ fabricated using a laser polymerization technique

Electroconvection is known to cause strong convective mixing in a microchannel near a nanoporous membrane or a nanochannel in contact with an electrolyte solution due to the external electric field. This study addresses micromixer behavior subject to electroconvection occurring near a nanoporous membrane in-situ fabricated by a laser polymerization technique on a microfluidic chip. We found that the micromixer behavior can be categorized into three regimes. Briefly, the weak electroconvection regime is characterized by weak mixing performance at a low applied voltage and KCl concentration, whereas the strong electroconvection regime has a high mixing performance when the applied voltage and KCl concentration are moderately high. Finally, the incomplete electroconvection regime has an incomplete electric double-layer overlap in the nanopores of the membrane when the electrolyte concentration is very high. The mixing index reached 0.92 in the strong electroconvection regime. The detailed fabrication methods for the micromixer and characterization results are discussed in this paper.     

A nanoporous optofluidic microsystem for highly sensitive and repeatable surface enhanced Raman spectroscopy detection

We report the demonstration of an optofluidic surface enhanced Raman spectroscopy (SERS) device that leverages a nanoporous microfluidic matrix to improve the SERS detection performance by more than two orders of magnitude as compared to a typical open microfluidic channel. Although it is a growing trend to integrate optical biosensors into microfluidic channels, this basic combination has been detrimental to the sensing performance when applied to SERS. Recently, however, synergistic combinations between microfluidic functions and photonics (i.e., optofluidics) have been implemented that improve the detection performance of SERS. Conceptually, the simplest optofluidic SERS techniques reported to date utilize a single nanofluidic channel to trap nanoparticle-analyte conjugates as a method of preconcentration before detection. In this work, we leverage this paradigm while improving upon the simplicity by forming a 3D nanofluidic network with packed nanoporous silica microspheres in a microfluidic channel; this creates a concentration matrix that traps silver nanoclusters and adsorbed analytes into the SERS detection volume. With this approach, we are able to achieve a detection limit of 400 attomoles of Rhodamine 6G after only 2 min of sample loading with high chip-to-chip repeatability. Due to the high number of fluidic paths in the nanoporous channel, this approach is less prone to clogging than single nanofluidic inlets, and the loading time is decreased compared to previous reports. In addition, fabrication of this microsystem is quite simple, as nanoscale fabrication is not necessary. Finally, integrated multimode fiber optic cables eliminate the need for optical alignment, and thus the device is relevant for portable and automated applications in the field, including point-of-sample and point-of-care detection. To illustrate a relevant field-based application, we demonstrate the detection of 12 ppb of the organophosphate malathion in water using the nanofluidic SERS microsystem.     

An optically transparent membrane supports shear stress studies in a three-dimensional microfluidic neurovascular unit model

We report a microfluidic blood-brain barrier model that enables both physiological shear stress and optical transparency throughout the device. Brain endothelial cells grown in an optically transparent membrane-integrated microfluidic device were able to withstand physiological fluid shear stress using a hydrophilized polytetrafluoroethylene nanoporous membrane instead of the more commonly used polyester membrane. A functional three-dimensional microfluidic co-culture model of the neurovascular unit is presented that incorporates astrocytes in a 3D hydrogel and enables physiological shear stress on the membrane-supported endothelial cell layer.     

Understanding electrokinetics at the nanoscale: A perspective

Electrokinetics promises to be the microfluidic technique of choice for portable diagnostic chips and for nanofluidic molecular detectors. However, despite two centuries of research, our understanding of ion transport and electro-osmotic flow in and near nanoporous membranes, whose pores are natural nanochannels, remains woefully inadequate. This short exposition reviews the various ion-flux and hydrodynamic anomalies and speculates on their potential applications, particularly in the area of molecular sensing. In the process, we revisit several old disciplines, with some unsolved open questions, and we hope to create a new one.     

Optofluidic in situ maskless lithography of charge selective nanoporous hydrogel for DNA preconcentration

An optofluidic maskless photopolymerization process was developed for in situ negatively charged nanoporous hydrogel [poly-AMPS (2-acrylamido-2-methyl-1-propanesulfonic acid)] fabrication. The optofluidic maskless lithography system, which combines a high power UV source and digital mirror device, enables fast polymerization of arbitrary shaped hydrogels in a microfluidic device. The poly-AMPS hydrogel structures were positioned near the intersections of two microchannels, and were used as a cation-selective filter for biological sample preconcentration. Preconcentration dynamics as well as the fabricated polymer shape were analyzed in three-dimensions using fluorescein sample and a confocal microscope. Finally, single-stranded DNA preconcentration was demonstrated for polymerase chain reaction-free signal enhancement.     

Dynamic superconcentration at critical-point double-layer gates of conducting nanoporous granules due to asymmetric tangential fluxes

A transient 10⁶-fold concentration of double-layer counterions by a high-intensity electric field is demonstrated at the exit pole of a millimeter-sized conducting nanoporous granule that permits ion permeation. The phenomenon is attributed to a unique counterion screening dynamics that transforms half of the surface field into a converging one toward the ejecting pole. The resulting surface conduction flux then funnels a large upstream electro-osmotic convective counterion flux into the injecting hemisphere toward the zero-dimensional gate of the ejecting hemisphere to produce the superconcentration. As the concentrated counterion is ejected into the electroneutral bulk electrolyte, it attracts co-ions and produce a corresponding concentration of the co-ions. This mechanism is also shown to trap and concentrate co-ion microcolloids of micron sizes too (macroions) and hence has potential application in bead-based molecular assays.     

Single nanopore transport of synthetic and biological polyelectrolytes in three-dimensional hybrid microfluidic∕nanofluidic devices

This paper presents a study of electrokinetic transport in single nanopores integrated into vertically stacked three-dimensional hybrid microfluidic∕nanofluidic structures. In these devices, single nanopores, created by focused ion beam (FIB) milling in thin polymer films, provide fluidic connection between two vertically separated, perpendicular microfluidic channels. Experiments address both systems in which the nanoporous membrane is composed of the same (homojunction) or different (heterojunction) polymer as the microfluidic channels. These devices are then used to study the electrokinetic transport properties of synthetic (i.e., polystyrene sulfonate and polyallylamine) and biological (i.e., DNA) polyelectrolytes across these nanopores using both electrical current measurements and confocal microscopy. Both optical and electrical measurements indicate that electro-osmotic transport is predominant over electrophoresis in single nanopores with d>180 nm, consistent with results obtained under similar conditions for nanocapillary array membranes.     

金属中激光超声的产生及应用

介绍了用不同脉宽、不同波长的钇铝石榴石(Nd:YAG)激光在不同厚度的金属样品中产生超声脉冲的实验。超声波的接收是用聚偏氟乙烯薄膜(PVDF)实现的。文中给出了激光超声脉冲及其在金属板中的回波的波形曲线;测量了不同条件下激光超声幅度与激光能量的关系,超声幅度与激光波长的关系,以及超声脉宽和激光脉宽的关系;观察到了激光超声的传播方向总是沿被照表面的法线方向,而与激光的入射角无关。实验结果表明,激光超声作为一种非接触的超声源,对于工业应用尤其是高温运动状态下对弯曲表面的工件(如管材等)进行厚度测量和探伤具有广阔的应用前景,也将是激光与物质相互作用领域的一种重要研究手段。     

Microfluidic enrichment of small proteins from complex biological mixture on nanoporous silica chip

The growing field of miniaturized diagnostics is hindered by a lack of pre-analysis treatments that are capable of processing small sample volumes for the detection of low concentration analytes in a high-throughput manner. This letter presents a novel, highly efficient method for the extraction of low-molecular weight (LMW) proteins from biological fluids, represented by a mixture of standard proteins, using integrated microfluidic systems. We bound a polydimethylsiloxane layer patterned with a microfluidic channel onto a well-defined nanoporous silica substrate. Using rapid, pressure-driven fractionation steps, this system utilizes the size-exclusion properties of the silica nanopores to remove high molecular weight proteins while simultaneously isolating and enriching LMW proteins present in the biological sample. The introduction of the microfluidic component offers important advantages such as high reproducibility, a simple user interface, controlled environment, the ability to process small sample volumes, and precise quantification. This solution streamlines high-throughput proteomics research on many fronts and may find broad acceptance and application in clinical diagnostics and point of care detection.     

应用函数RND(x)模拟随机现象

本文阐述了如何应用计算机来模拟一些常见的随机现象,包括定性的随机变量、离散型随机变量、连续型随机变量及标准模型的处理。