共查询到20条相似文献,搜索用时 171 毫秒
1.
海洋生物单细胞的扫描电镜样品制备 总被引:1,自引:0,他引:1
在海洋基础生物学研究领域中 ,细胞超微形态的研究占据着相当重要的地位 ,其中包括鱼虾贝类血细胞、动物精子及浮游藻等单细胞形貌的观察和研究。对于这些单细胞生物的研究在免疫学、发育生物学及饵料生物学等领域中也是相当重要的。因此 ,我们对海洋生物单细胞样品 ,如养殖海洋鱼、虾、扇贝、牡蛎等的血细胞、精子和一些海水单细胞浮游藻类生物等 ,进行了扫描电镜样品制备方法的探讨和研究。经过对这类样品的大量前期处理实验 ,找到了一些操作简便、周期短、效果较好的制备单细胞海洋生物样品的方法。本文将太平洋牡蛎精子和美国红鱼血细胞… 相似文献
2.
单细胞操作和分析对于研究许多基本生物学过程和揭示细胞异质性至关重要,并且在生物医学领域具有巨大的应用潜力。液滴微流控技术在单细胞分析方面具有显著优势。研制了一种深度学习驱动的液滴微流控单细胞分选系统,主要以液滴内所包含的生物样本种类以及数量作为标准分选目标液滴。根据实验需求制作好相应生物样本的数据集,在服务器上训练好对应的网络模型,并将该网络模型转移到NVIDIA Jetson TX2开发板上,利用该网络模型对实验过程中拍摄到的液滴图像进行实时检测判断,最后根据算法对包含特定物质的液滴进行分选,从而得到目标液滴。此方法能够有效地判断并分选出液滴内图像特征有差异的不同生物样本,可以实现对包含单个及2个细胞液滴的分选。该研究为液滴微流控单细胞分选技术在生物学和医学等领域的广泛应用提供了支撑。 相似文献
3.
研究基因序列和单细胞的基因如何调整和表达的科学家们需要一种研究单细胞中DNA的工具。为了了解细胞如何变化即是否转变成胚胎或肿瘤,生物学家期望能一次一个地隔离和分析单细胞。虽然有极其灵敏的分析微量材料的方法,如基于DNA放大的(聚合链反应)或RT(反转录醇),但是这些方法对污染物极其敏感。在慕尼黑—哈拉兴学院附属医院的两位研究人员发表了一篇扩展以前证明有效的方法的论文,该方法能精确地从其它细胞中无污染地分开和隔离单个细胞。卡林·苏策和乔治亚·拉赫演示了如何采用此方法分离一个单独癌细胞,并通过分析细胞来找出点突变。 相似文献
4.
5.
简要介绍了半导体金刚石材料优异的电学和光学性质、主要制备方法以及采用微波等离子体化学气相沉积(MPCVD)技术在制备高质量半导体金刚石材料方面的优势。重点就MPCVD技术在半导体金刚石材料的高速率生长、大尺寸生长、高质量生长以及电学掺杂等四个方面的研究现状进行了详细总结。详细探讨了目前半导体金刚石材料在大尺寸单晶金刚石衬底制备、高质量单晶金刚石外延层生长以及金刚石电学掺杂等方面还存在的一些基本问题。指出在大面积单晶金刚石衬底还没有实现突破的情况下,半导体金刚石材料和器件结构的生长模式。 相似文献
6.
利用扫描电子显微镜对黑龙江苹果亚科14种植物叶表皮微形态进行比较研究。结果显示:(1)叶表皮细胞呈多边形或无规则形,垂周壁式样呈平直或弓形、浅波纹、深波纹;(2)除无毛花楸无表皮毛外,其它均具有表皮毛,类型均为单细胞不分支非腺毛;(3)叶表皮纹饰呈均匀分布蜡质纹饰和仅气孔周围有蜡质条纹;(4)气孔器均在下表皮分布,且气孔器类型为轮列型、无规则型或不典型辐射型;气孔外拱盖为单层或双层,内缘近平滑或不规则波状;保卫细胞两极仅在水榆花楸、毛山楂、黑果栒子和全缘栒子中出现"T"型加厚。研究表明,该亚科下5属间的叶表皮微形态特征存在一定差异,属内种间在气孔器、表皮毛以及表皮纹饰特征上存在一致性,为属间的系统分类和演化提供了形态结构的依据。 相似文献
7.
《微纳电子技术》2019,(5):376-381
提出了基于电力聚焦的单模光纤耦合激光分选细胞的方法。基于电力聚焦模型和光镊原理,推导出中心聚焦流宽度公式和光纤光镊对细胞的散射力公式。在Comsol Multiphysics 5.3中建立层流、电流、粒子追踪和电磁波四个物理场,进行了直径10μm和20μm粒子的单细胞流和分选仿真。在此基础上,搭建了光纤光镊分选细胞实验平台,配置了酵母菌细胞和聚苯乙烯微球的混合溶液,进行了实验。仿真和实验结果均表明,在入口电压比1∶1.2的情况下,在主通道中能形成间距大致均匀相等的单细胞流。并在波长为980 nm、功率为300 mW激光条件下,聚焦激光可以通过单模光纤驱动不同直径的细胞沿光轴方向移动,且移动距离不相等,从而迫使细胞进入不同的通道进行分选。 相似文献
8.
9.
10.
11.
Stephen A. Morin Sen Wai Kwok Joshua Lessing Jason Ting Robert F. Shepherd Adam A. Stokes George M. Whitesides 《Advanced functional materials》2014,24(35):5541-5549
This paper describes the fabrication of 3D soft, inflatable structures from thin, 2D tiles fabricated from elastomeric polymers. The tiles are connected using soft joints that increase the surface area available for gluing them together, and mechanically reinforce the structures to withstand the tensile forces associated with pneumatic actuation. The ability of the elastomeric polymer to withstand large deformations without failure makes it possible to explore and implement new joint designs, for example “double‐taper dovetail joints,” that cannot be used with hard materials. This approach simplifies the fabrication of soft structures comprising materials with different physical properties (e.g., stiffness, electrical conductivity, optical transparency), and provides the methods required to “program” the response of these structures to mechanical (e.g., pneumatic pressurization) and other physical (e.g., electrical) stimuli. The flexibility and modularity of this approach is demonstrated in a set of soft structures that expanded or buckled into distinct, predictable shapes when inflated or deflated. These structures combine easily to form extended systems with motions dependent on the configurations of the selected components, and, when fabricated with electrically conductive tiles, electronic circuits with pneumatically active elements. This approach to the fabrication of hollow, 3D structures provides routes to new soft actuators. 相似文献
12.
Buse Aktaş Yashraj S. Narang Nikolaos Vasios Katia Bertoldi Robert D. Howe 《Advanced functional materials》2021,31(16):2007554
Jamming is a structural phenomenon that provides tunable mechanical behavior. A jamming structure typically consists of a collection of elements with low effective stiffness and damping. When a pressure gradient, such as vacuum, is applied, kinematic and frictional coupling increase, resulting in dramatically altered mechanical properties. Engineers have used jamming to build devices from tunable-stiffness grippers to tunable-damping landing gear. This study presents a rigorous framework that systematically guides the design of jamming structures for target applications. The force-deflection behavior of major types of jamming structures (i.e., grain, fiber, and layer) in fundamental loading conditions (e.g., tension, shear, and bending) is compared. High-performing pairs (e.g., grains in compression, layers in shear, and bending) are identified. Parameters that go into designing, fabricating, and actuating a jamming structure (e.g., scale, material, geometry, and actuator) are described, along with their effects on functional metrics. Two key methods to expand on the design space of jamming structures are introduced: using structural design to achieve effective tunable-impedance behavior in specific loading directions, and creating hybrid jamming structures to utilize the advantages of different types of jamming. Collectively, this study elaborates and extends the jamming design space, providing a conceptual modeling framework for jamming-based structures. 相似文献
13.
Zhen Li Özgül Kurtulus Nan Fu Zhe Wang Andreas Kornowski Ullrich Pietsch Alf Mews 《Advanced functional materials》2009,19(22):3650-3661
Semiconductor nanowires prepared by wet chemical methods are a relatively new field of 1D electronic systems, where the dimensions can be controlled by changing the reaction parameters using solution chemistry. Here, the solution–liquid–solid approach where the nanowire growth is governed by low‐melting‐point catalyst particles, such as Bi nanocrystals, is presented. In particular, the focus is on the preparation and characterization of CdSe nanowires, a material which serves a prototype structure for many kinds of low dimensional semiconductor systems. To investigate the influence of different reaction parameters on the structural and optical properties of the nanowires, a comprehensive synthetic study is presented, and the results are compared with those reported in literature. How the interplay between different reaction parameters affects the diameter, length, crystal structure, and the optical properties of the resultant nanowires are demonstrated. The structural properties are mainly determined by competing reaction pathways, such as the growth of Bi nanocatalysts, the formation and catalytic growth of nanowires, and the formation and uncatalytic growth of quantum dots. Systematic variation of the reaction parameters (e.g., molecular precursors, concentration and concentration ratios, organic ligands, or reaction time, and temperature) enables control of the nanowire diameter from 6 to 33 nm, while their length can be adjusted between several tens of nanometers and tens of micrometers. The obtained CdSe nanowires exhibit an admixture of wurtzite (W) and zinc blende (ZB) structure, which is investigated by X‐ray diffraction. The diameter‐dependent band gaps of these nanowires can be varied between 650 and 700 nm while their fluorescence intensities are mainly governed by the Cd/Se precursor ratio and the ligands used. 相似文献
14.
The present work elucidates the microstructural changes and their impact on electrical resistivity and mechanical behavior of Sn-3.5 wt% Ag electronic interconnect material after exposure at high-temperature and relative humidity (85 °C/85%) environment. An in-depth structural observation is performed through electron microscopy e.g., SEM, EBSD and TEM techniques. The microstructural analysis shows that the as-received sample contained sub-micron size ε-Ag3Sn intermetallic compound (IMC) and dendritic structure having a special orientation 〈100〉60° relationship with the matrix grains. However, it is found that after exposing the material at the harsh service environment for 60 days, the morphology, and size of the matrix grains and the ε-Ag3Sn IMC phase are significantly altered. Such microstructural changes impact negatively on their material properties e.g., electrical resistivity, elastic and shear moduli, hardness and creep performance. An assessment between the as-cast and the aged material demonstrated that the degradations in hardness and elastic modulus are approximately 21.8 and 31.7%, respectively. Subsequently, the heat-treated material displays a higher temperature and strain amplitude-dependence damping characteristic as compared to the as-cast solder material. 相似文献
15.
Qujiang Sun Zhen Cao Junli Zhang Haoran Cheng Jiao Zhang Qian Li Hai Ming Gang Liu Jun Ming 《Advanced functional materials》2021,31(22):2009122
Designing carbon nanotubes (CNTs)-based materials are attracting great attention due to their fantastic properties and greater performance. Herein, a new CNTs network triggered by metal catalysts (e.g., Co, Ni, or Cu) is constructed on metal oxide (e.g., MnO) microparticles, giving rise to a high-performance Co-MnO@C-CNTs anode in lithium-ion batteries (LIBs). An extremely high capacity of 1050 mAh g−1, extraordinary rate capacities over 10 A g−1, and a long lifespan over 500 cycles are demonstrated. The great features of Co-MnO@C-CNTs anode are further confirmed in LIBs when the nickel-rich cathode (e.g., LiNi0.8Co0.1Mn0.1O2) is used and charged at a high voltage over 4.5 V. A high-capacity retention of 71.5% can be maintained at 1 C over 150 cycles. The superior performance relates to the CNTs network, which not only acts as an “expressway network” for fast ion/electron transportation but also buffers structural variation. Moreover, the metal nanoparticles can also enhance the electrical conductivity and catalyze the (de-)lithiation of metal oxide, resulting in higher reversibility and long-term cyclability. This study opens a new avenue to prepare CNTs-based functional materials and also explores the potential applications of metal oxide-based anode for high-performance batteries. 相似文献
16.
This report on fuel cell research on the European continent deals with the main lines of present activities, i.e., high temperature cells with semi-solid electrolytes, the Bacon HYDROX cell operating at medium temperatures and high pressures and the electrochemical energy converters operating at ambient temperature and pressure. The author devotes the main part of his report to these low temperature types including the Double Skeleton Catalyst ("DSK") system of the German Fuel Cell Consortium, the Swiss Monoskeleton ("MSK") system and the German system of dissolving a liquid carbonaceous fuel such as methanol in a cell with catalytically different electrodes. In addition, various applications of such cells, e.g., for storage of electrical energy by electrolysis of water and subsequent recombination of hydrogen and oxygen are reviewed. 相似文献
17.
Carbide‐derived carbons (CDCs) are a large family of carbon materials derived from carbide precursors that are transformed into pure carbon via physical (e.g., thermal decomposition) or chemical (e.g., halogenation) processes. Structurally, CDC ranges from amorphous carbon to graphite, carbon nanotubes or graphene. For halogenated carbides, a high level of control over the resulting amorphous porous carbon structure is possible by changing the synthesis conditions and carbide precursor. The large number of resulting carbon structures and their tunability enables a wide range of applications, from tribological coatings for ceramics, or selective sorbents, to gas and electrical energy storage. In particular, the application of CDC in supercapacitors has recently attracted much attention. This review paper summarizes key aspects of CDC synthesis, properties, and applications. It is shown that the CDC structure and properties are sensitive to changes of the synthesis parameters. Understanding of processing–structure–properties relationships facilitates tuning of the carbon material to the requirements of a certain application. 相似文献
18.
Carbide‐derived carbons (CDCs) are a large family of carbon materials derived from carbide precursors that are transformed into pure carbon via physical (e.g., thermal decomposition) or chemical (e.g., halogenation) processes. Structurally, CDC ranges from amorphous carbon to graphite, carbon nanotubes or graphene. For halogenated carbides, a high level of control over the resulting amorphous porous carbon structure is possible by changing the synthesis conditions and carbide precursor. The large number of resulting carbon structures and their tunability enables a wide range of applications, from tribological coatings for ceramics, or selective sorbents, to gas and electrical energy storage. In particular, the application of CDC in supercapacitors has recently attracted much attention. This review paper summarizes key aspects of CDC synthesis, properties, and applications. It is shown that the CDC structure and properties are sensitive to changes of the synthesis parameters. Understanding of processing–structure–properties relationships facilitates tuning of the carbon material to the requirements of a certain application. 相似文献
19.
Biomimetic Chitin–Silk Hybrids: An Optically Transparent Structural Platform for Wearable Devices and Advanced Electronics 下载免费PDF全文
Moo‐Seok Hong Gwang‐Mun Choi Joohee Kim Jiuk Jang Byeongwook Choi Joong‐Kwon Kim Seunghwan Jeong Seongmin Leem Hee‐Young Kwon Hyun‐Bin Hwang Hyeon‐Gyun Im Jang‐Ung Park Byeong‐Soo Bae Jungho Jin 《Advanced functional materials》2018,28(24)
The cuticles of insects and marine crustaceans are fascinating models for man‐made advanced functional composites. The excellent mechanical properties of these biological structures rest on the exquisite self‐assembly of natural ingredients, such as biominerals, polysaccharides, and proteins. Among them, the two commonly found building blocks in the model biocomposites are chitin nanofibers and silk‐like proteins with β‐sheet structure. Despite being wholly organic, the chitinous protein complex plays a key role for the biocomposites by contributing to the overall mechanical robustness and structural integrity. Moreover, the chitinous protein complex alone without biominerals is optically transparent (e.g., dragonfly wings), thereby making it a brilliant model material system for engineering applications where optical transparency is essentially required. Here, inspired by the chitinous protein complex of arthropods cuticles, an optically transparent biomimetic composite that hybridizes chitin nanofibers and silk fibroin (β‐sheet) is introduced, and its potential as a biocompatible structural platform for emerging wearable devices (e.g., smart contact lenses) and advanced displays (e.g., transparent plastic cover window) is demonstrated. 相似文献
20.
This work introduces a tutorial series on material failure mechanisms and damage models to familiarize nonspecialists with the fundamentals of failure mechanisms in engineering assemblies. Since failure is a complicated concept, four simple conceptual models for failure are discussed: stress-strength, damage-endurance, challenge-response, and tolerance-requirement. The specific failure mechanisms depend on material or structural defects, damage induced during manufacture and assembly, and on conditions during storage and field use. Conditions that affect the state of an item are broadly termed stresses (loads), e.g., mechanical stress and strain, electrical current and voltage, temperature, humidity, chemical environment, and radiation. The effects of stresses are influenced by geometry, constitutive and damage properties of the materials, manufacturing parameters, and the application environment 相似文献