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121.
After the introduction of a corrector to compensate for the spherical aberration of a TEM and the acceptance of this new instrumentation for high-resolution CTEM (conventional transmission electron microscope) and STEM (scanning transmission electron microscope) by the electron microscopy community, a demand for even higher resolution far below 1A has emerged. As a consequence several projects around the world have been launched to make these new instruments available and to further push the resolution limits down toward fractions of 1A. For this purpose the so-called TEAM (transmission electron aberration-corrected microscope) has been initiated and is currently under development. With the present paper we give a detailed assessment of the stability required for the base instrument and the electric stability, the manufacturing precision, and feasible semi-automatic alignment procedures for a novel C(c)/C(s)-corrector in order to achieve aberration-free imaging with an information limit of 0.5A at an acceleration voltage of 200 kV according to the goals for the first TEAM instrument. This new aberration corrector, a so-called Achroplanat, in combination with a very stable high-resolution TEM leads to an imaging device with unprecedented resolving power and imaging properties. 相似文献
122.
Tomas Strharsky Dominika Pindjakova Jiri Kos Lucia Vrablova Hana Michnova Jan Hosek Nicol Strakova Veronika Lelakova Lenka Leva Lenka Kavanova Michal Oravec Alois Cizek Josef Jampilek 《International journal of molecular sciences》2022,23(6)
A series of eighteen 4-chlorocinnamanilides and eighteen 3,4-dichlorocinnamanilides were designed, prepared and characterized. All compounds were evaluated for their activity against gram-positive bacteria and against two mycobacterial strains. Viability on both cancer and primary mammalian cell lines was also assessed. The lipophilicity of the compounds was experimentally determined and correlated together with other physicochemical properties of the prepared derivatives with biological activity. 3,4-Dichlorocinnamanilides showed a broader spectrum of action and higher antibacterial efficacy than 4-chlorocinnamanilides; however, all compounds were more effective or comparable to clinically used drugs (ampicillin, isoniazid, rifampicin). Of the thirty-six compounds, six derivatives showed submicromolar activity against Staphylococcus aureus and clinical isolates of methicillin-resistant S. aureus (MRSA). (2E)-N-[3,5-bis(trifluoromethyl)phenyl]- 3-(4-chlorophenyl)prop-2-enamide was the most potent in series 1. (2E)-N-[3,5-bis(Trifluoromethyl)phenyl]-3-(3,4-dichlorophenyl)prop-2-enamide, (2E)-3-(3,4-dichlorophenyl)-N-[3-(trifluoromethyl)phenyl]prop-2-enamide, (2E)-3-(3,4-dichloro- phenyl)-N-[4-(trifluoromethyl)phenyl]prop-2-enamide and (2E)-3-(3,4-dichlorophenyl)- N-[4-(trifluoromethoxy)phenyl]prop-2-enamide were the most active in series 2 and in addition to activity against S. aureus and MRSA were highly active against Enterococcus faecalis and vancomycin-resistant E. faecalis isolates and against fast-growing Mycobacterium smegmatis and against slow-growing M. marinum, M. tuberculosis non-hazardous test models. In addition, the last three compounds of the above-mentioned showed insignificant cytotoxicity to primary porcine monocyte-derived macrophages. 相似文献
123.
为分析纤维空气过滤材料的流场演变情况,综合过滤效率及颗粒流动轨迹,基于随机算法建立了纤维空气过滤材料的三维模型,并采用计算流体力学中的欧拉-拉格朗日离散相模型,在雷诺相似准则的基础上研究了微米纤维介质中的气固流动特性。结果表明:入口速度变化对流场压力与速度场分布有明显影响,随着入口速度增大,阻滞区域面积增加,流场空隙处更易形成高速流动与速度漩涡,同时流场整体速度差增大,压力损失与入口速度呈正相关;纤维模型对平均粒径为8~18 mm颗粒的过滤效率较为稳定,均在80.4%~84%,在入口速度为2 m/s工况下,过滤效率与粒径接近正比例关系。 相似文献
124.
In this paper, we systematically assess the performance of an automatic calibration chart detector. Through simulation we
establish the optimal set of control parameters and the rate of successful detection as a function of pose. We validate the
simulation results on real images taken from a camera mounted on a robot arm. The results confirm the utility of such simulation
studies. The feedback obtained suggested a number of modifications for the chart detection system, which led to a significant
improvement in performance. In particular, the chart design was changed to accommodate wider range and better stability in
detection.
Received: 16 December 1999 / Accepted: 15 October 2000 相似文献
125.
126.
Vaclav Prajzler Ivan Huttel Oleksiy Lyutakov Jiri Oswald Vladimir Machovic Vitezslav Jerabek 《Polymer Engineering and Science》2009,49(9):1814-1817
In this article, we report the fabrication and optical/spectroscopic properties of polymethylmethacrylate (PMMA) doped with rare earth (RE) (Er3+ and Er3+/Yb3+) ions. Infrared spectroscopy revealed only very weak O? H stretching vibration peaks in the samples, which is important if satisfactory photoluminescence is to be observed at 1530 nm. Measurement of transmission spectra in the wavelength ranges from 300 to 700 nm for Er3+‐doped samples and from 900 to 1050 nm for Yb3+‐doped samples enabled us to observe the 4G11/2 (377 nm) and 2H11/2 (519 nm) transmission bands typical for Er3+‐doped samples, as well as the 2F5/2 (975 nm) band typical for Yb3+‐doped samples. Under excitation at 980 nm, at room temperature, the characteristic Er3+ emission at 1530 nm was also observed with improving trend when the higher RE concentrations were applied. The results indicate that the PMMA reveals very low tendency to the RE clustering, which together with low cost and easy fabrication make it a material with a great potential in the active photonics devices. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers 相似文献
127.
Jiri Krejci Rahula Janis 《皮革科学与工程》2003,13(5):8-15
研究了明胶B及含铬削匀屑酶法脱铬后的水解产物和羧甲基纤维素反应生成不溶性聚合电解质络合物的过程,确定了这两种反应相同的最适宜的反应条件(水解产物pH~3;竣甲基纤维素pH~7;羧甲基纤维素与水解产物比率(g/g)~0.5),分子量小于2,500g*mol-1的胶原水解产物不能与羧甲基纤维素反应生成不溶性络合物.用这些络合物制成膜,其热稳定性和强度都较低,只有经过进一步交联反应才能有显著提高. 相似文献
128.
Bakandritsos A Papagiannopoulos A Anagnostou EN Avgoustakis K Zboril R Pispas S Tucek J Ryukhtin V Bouropoulos N Kolokithas-Ntoukas A Steriotis TA Keiderling U Winnefeld F 《Small (Weinheim an der Bergstrasse, Germany)》2012,8(15):2381-2393
Hybrid magnetic drug nanocarriers are prepared via a self-assembly process of poly(methacrylic acid)-graft-poly(ethyleneglycol methacrylate) (p(MAA-g-EGMA)) on growing iron oxide nanocrystallites. The nanocarriers successfully merge together bio-repellent properties, pronounced magnetic response, and high loading capacity for the potent anticancer drug doxorubicin (adriamicin), in a manner not observed before in such hybrid colloids. High magnetic responses are accomplished by engineering the size of the magnetic nanocrystallites (~13.5 nm) following an aqueous single-ferrous precursor route, and through adjustment of the number of cores in each colloidal assembly. Complementing conventional magnetometry, the magnetic response of the nanocarriers is evaluated by magnetophoretic experiments providing insight into their internal organization and on their response to magnetic manipulation. The structural organization of the graft-copolymer, locked on the surface of the nanocrystallites, is further probed by small-angle neutron scattering on single-core colloids. Analysis showed that the MAA segments selectively populate the area around the magnetic nanocrystallites, while the poly(ethylene glycol)-grafted chains are arranged as protrusions, pointing towards the aqueous environment. These nanocarriers are screened at various pHs and in highly salted media by light scattering and electrokinetic measurements. According to the results, their stability is dramatically enhanced, as compared to uncoated nanocrystallites, owing to the presence of the external protective PEG canopy. The nanocarriers are also endowed with bio-repellent properties, as evidenced by stability assays using human blood plasma as the medium. 相似文献
129.
非木浆OQP漂白及其与CEH漂白的比较 总被引:6,自引:1,他引:6
进行了芦苇、麦草和蔗渣烧碱-蒽醌法纸浆OQP漂白的研究,并与常规的CEH漂白结果作了比较。研究结果表明,3种非木材纸浆经OQP和CEH流程漂白,白度均可达到80%ISO以上。与CEH漂白浆相比,OQP漂白浆的白度略低,但白度稳定性较好,粘度和强度较高,而且0段废液可送至碱回收系统进行回收,QP漂白废水的污染负荷比CEH漂白废水的污染负荷低得多。 相似文献
130.
Application of textile waste for development of value added green composites has been carried out in this work. Textile fabric waste is collected from various sources. These waste materials are garneted, so as to produce loose fibrous material, subsequently this fibrous material was converted into twisted strand for manufacturing of 3D woven preforms for production of composites. Twisted strands are converted into orthogonal 3D woven structure. The fibers extracted from waste material are combined with polypropylene in 60/40 proportion. Composites of various specifications are developed to examine their end-use applications. These composite materials are characterized for their mechanical behavior to find out the response against tensile loading, flexural stress, and impact force. The effects of moisture absorption on mechanical properties of composites are investigated. 3D woven fabric reinforced composites produced by using waste fiber yarn and normal cotton OE yarn do not exhibit any significant difference in the mechanical behavior of composite. This result confirmed that waste material can be safely used as reinforcing structure in green composite manufacturing. 相似文献