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排序方式: 共有255条查询结果,搜索用时 15 毫秒
1.
Molecular Ordering: Selectivity of Threefold Symmetry in Epitaxial Alignment of Liquid Crystal Molecules on Macroscale Single‐Crystal Graphene (Adv. Mater. 40/2018) 下载免费PDF全文
2.
Jessica H. Sathissarat Lianrui Chu Robert Danso H. Ralph Rawls Kyumin Whang 《应用聚合物科学杂志》2021,138(31):50773
This research continued the development of a difunctional Oxirane and multifunctional Acrylate interpenetrating polymer network composite System (OASys) with antimicrobial properties. The effects of 4-Isopropyl-4′-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate (Borate), hexamethylene diamine (HMDA) and N,N-dimethyl p-toluidine (DMPT) on OASys (Epalloy 5001:dipentaerythritol hexaacrylate) composite hardness, contact angle, monomer-to-polymer degree of conversion (DoC), mechanical properties, polymerization shrinkage, shrinkage stress, and antimicrobial properties were determined. Bis-GMA:TEGDMA composites were used as the control. OASys composites with 9 wt% Borate and 0.5 wt% DMPT or 1.5 wt% HMDA had comparable hardness, DoC's and polymerization shrinkages to controls, but had lower contact angles and mechanical properties. Additionally, OASys composites with 1.5 wt% HMDA had significantly less polymerization stress than controls and demonstrated significant antibacterial activity against Streptococcus mutans and Lactobacillus casei out to 3 months. With lower shrinkage stress and long-term antimicrobial activity, OASys composites look promising for increasing the clinical lifetime of dental composites, but improvements in mechanical properties are needed. 相似文献
3.
Lifelog is a digital record of an individual’s daily life. It collects, records, and archives a large amount of unstructured data; therefore, techniques are required to organize and summarize those data for easy retrieval. Lifelogging has been utilized for diverse applications including healthcare, self-tracking, and entertainment, among others. With regard to the image-based lifelogging, even though most users prefer to present photos with facial expressions that allow us to infer their emotions, there have been few studies on lifelogging techniques that focus upon users’ emotions. In this paper, we develop a system that extracts users’ own photos from their smartphones and configures their lifelogs with a focus on their emotions. We design an emotion classifier based on convolutional neural networks (CNN) to predict the users’ emotions. To train the model, we create a new dataset by collecting facial images from the CelebFaces Attributes (CelebA) dataset and labeling their facial emotion expressions, and by integrating parts of the Radboud Faces Database (RaFD). Our dataset consists of 4,715 high-resolution images. We propose Representative Emotional Data Extraction Scheme (REDES) to select representative photos based on inferring users’ emotions from their facial expressions. In addition, we develop a system that allows users to easily configure diaries for a special day and summaize their lifelogs. Our experimental results show that our method is able to effectively incorporate emotions into lifelog, allowing an enriched experience. 相似文献
4.
Eun-Ok Oh Chin-Myung Whang Yu-Ri Lee Jong-Heun Lee Kyung Joong Yoon Byung-Kook Kim Ji-Won Son Jong-Ho Lee Hae-Weon Lee 《Journal of the European Ceramic Society》2012,32(8):1733-1741
A 500 nm thick thin film YSZ (yttria-stabilized zirconia) electrolyte was successfully fabricated on a conventionally processed anode substrate by spin coating of chemical solution containing slow-sintering YSZ nanoparticles with the particle size of 20 nm and subsequent sintering at 1100 °C. Incorporation of YSZ nanoparticles was effective for suppressing the differential densification of ultrafine precursor powder by mitigating the prevailing bi-axial constraining stress of the rigid substrate with numerous local multi-axial stress fields around them. In particular, adding 5 vol% YSZ nanoparticles resulted in a dense and uniform thin film electrolyte with narrow grain size distribution, and fine residual pores in isolated state. The thin film YSZ electrolyte placed on a rigid anode substrate with the GDC (gadolinia-doped ceria) and LSC (La0.6Sr0.4CoO3?δ) layers deposited by PLD (pulsed laser deposition) processes revealed that it had fairly good gas tightness relevant to a SOFC (solid oxide fuel cell) electrolyte and maintained its structural integrity during fabrication and operation processes. In fact, the open circuit voltage was 1.07 V and maximum power density was 425 mW/cm2 at 600 °C, which demonstrates that the chemical solution route can be a viable means for reducing electrolyte thickness for low- to intermediate-temperature SOFCs. 相似文献
5.
Nano-Micro Letters - A facile approach was demonstrated for fabricating high-performance nonvolatile memory devices based on ferroelectric-gate field effect transistors using a p-type Si nanowire... 相似文献
6.
Nd-doped Bi4Ge3O12 (Nd:BGO) crystals were successfully grown in the auto-diameter control system equipped with a frequency weighing sensor with
the Czochralski method. The Nd3+ ion doping level was varied from 0.25 to 2.5 at.%. The crystals were transparent and of light purple color, with a typical
size of about 20 mm in diameter and 50 mm in length. The effective distribution coefficient (keff) of Nd3+ ion was about 0.957 irrespective of concentration, and the Nd3+ ions were distributed homogeneously throughout the crystal. The doping concentration (pi) of active ion in Nd:BGO crystal was 2.54x1020 ions/cm3, which is higher than that in the Nd:YAG crystal. Therefore, the Nd:BGO crystal was judged to be more suitable for the laser
diode pumping microchip laser material where size reduction was desirable. 相似文献
7.
Decomposition kinetics in thermogravimetric analysis (TGA) and dynamic mechanical relaxation in dynamic mechanical analysis
(DMA) are used to study the high temperature lifetime of the new type of polyimide/poly(silsesquioxane)-like (PI/PSSQ-like)
hybrid films, which are designed to form three-dimensional structures with linear polyimide blocks and a crosslinked PSSQ-like
structure. Both TGA and DMA analysis reveal that the PI/PSSQ-like hybrid films have a longer lifetime (are more reliable)
with regard to their thermal and mechanical characteristics than that of pure PI. Even just 2 wt% of p-aminophenyltrimethoxysilane (APTS) in a PI/PSSQ-like hybrid film can significantly improve the service lifetime by as much
as at least four times in a TGA decomposition kinetic study. The dynamical relaxation data are well fitted to the calculated
WLF (Williams-Landel-Ferry) master curves. In a series of X-PIS (PI modified with APTS) hybrid films, decreasing the PI block
chain length increases the decomposition activation energy, lifetime (in both TGA and DMA) and relaxation modulus. In a series
of X-PIS-y-PTS [PI modified with APTS and phenyltrimethoxysilane (PTS)] films, the decomposition activation energy and lifetime
(in TGA) increase with the PTS content. Interestingly, the dynamic mechanical relaxation modulus of 10000-PIS-100-PTS film
is lower than that of the corresponding 10000-PIS film at frequency > 102 rad/sec, but higher at frequency < 102 rad/sec. The 10000-PIS-100-PTS has a lower relaxation time than the 10000-PIS at the modulus 5×108 Pa, but the relaxation time of the former becomes higher at 5×107 Pa. 相似文献
8.
Een-Kee Hong Seung-Hoon Hwang Ki-Jun Kim Keum-Chan Whang 《Communications, IEEE Transactions on》1999,47(11):1632-1635
In this letter, a timing control algorithm is described, which realizes timing synchronization on the direct sequence code-division multiple-access reverse link. In addition, the uncoded bit-error probability is analytically derived. Numerical results, confirmed by simulation, show that our synchronous transmission technique can offer better performance than conventional asynchronous transmission, especially for an exponentially decaying multipath intensity profile with a large decay factor 相似文献
9.
10.
Poly(1-octylpyrrolyl)squaraine and poly(3-octylpyrrolyl)squaraine were synthesized from squaric acid with 1-octylpyrrole and 3-octylpyrrole under identical conditions of condensation. Visible absorption spectra, photoluminescence spectra, TGA curves, and IR spectra were recorded to characterize the structures of these polymers as synthesized; the measured optical and thermal properties are consistent with backbone structures. The polysquaraine from 3-octylpyrrole possesses mostly zwitterionic repeating units (>97%), but the polymer from 1-octylpyrrole consists of zwitterionic and covalent repeating units in a ratio 2:1. Observations from the visible absorption and photoluminescence spectra in varied solvents, TGA curves, and thermal IR measurements for these two polymers reconciled to their structures. This result indicates that the position of the alkyl group in the pyrrole derivative affects the conformation in the condensation of poly(pyrrolyl)squaraine. These polysquaraines are stable below temperature 155 °C and their visible absorption and photoluminescence properties in hydrogen-bonding solvents exhibit negative solvatochromism. 相似文献