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排序方式: 共有302条查询结果,搜索用时 31 毫秒
1.
The implementation on the vector processor of Incomplete LU factorization in the Preconditioned Conjugate Gradient method and other Preconditioned CG-like methods for the numerical solutions of the partial differential equations is discussed. For sufficient vectorization, a variant of the standard 5-point difference scheme for 2-dimensional problems is introduced. The convergence property of ILU factorization for this variant is examined in comparison with that vectorized with the usual hyperplane ordering method for the standard 5-point difference scheme on the vector processor. The efficiency and effectiveness of this factorization for the variant of the difference scheme is demonstrated through several computational experiments. 相似文献
2.
Summary The permeation and separation characteristics of methanol/n-pentanol systems and n-propanol/n-heptane systems through nylon 12 membranes were studied by changing the feed composition of the binary organic mixtures. These characteristics were discussed from the viewpoints of physical and chemical nature of the permeating molecules and the membrane. 相似文献
3.
Because of their unique structures and properties, π-conjugated polymers have attracted the attention of scientists and engineers. The authors have studied the synthesis of two kinds of π-conjugated poly(aromatic acetylene)s, i.e. poly(arylacetylene)s and poly(aryleneethynylene)s with the aim of obtaining new polymers having novel functions or higher performances. This review mainly concerns the authors' results, as follows: first, we describe the synthesis and properties of achiral poly(arylacetylene)s, containing trimethylsilyl groups, oligodimethylsiloxanyl groups, dendritic groups, and glavinoxyl groups, for application as oxygen permselective membrane materials. Their self-membrane-forming abilities and high oxygen permeabilities are presented. Second, the synthesis by asymmetric-induced polymerization of chiral poly(arylacetylene)s having both a main-chain chirality and chiral pendant groups and their application as optical resolution membranes are described. Third, two new synthetic methods for preparing chiral helical poly(phenylacetylene)s without the coexistence of any other chiral moieties are presented. One is helix-sense-selective addition polymerization and the other is in situ removal of chiral pendant groups from membranes of poly(arylacetylene)s that also contain a main-chain chirality. The chiral helical poly(arylacetylene)s were tested as optical resolution membranes. The chiral and achiral poly(arylacetylene)s were synthesized by addition polymerization using metathesis catalysts or rhodium complexes. Finally, the synthesis of regiospecific poly(aryleneethynylene)s bearing stable radicals by the polycondensation of bromoethynylanthracene derivatives using a Pd(0) complex is described. The magnetization and the static magnetic susceptibility of the polyradicals are explained. 相似文献
4.
Riho Kataishi Takayuki Ikeda Toshiki Sasaki Kouhei Toyotaka Daiki Nakamura Hiroyuki Miyake Yuji Iwaki Kazunori Watanabe Yuichi Yanagisawa Hisao Ikeda Harue Nakashima Nobuharu Ohsawa Shingo Eguchi Satoshi Seo Yoshiharu Hirakata Shunpei Yamazaki Daisuke Kurosaki Masakatsu Ohno Chris Bower Darryl Cotton Andrew Matthews Piers Andrew Catalin Gheorghiu Johan Bergquist 《Journal of the Society for Information Display》2014,22(8):381-392
In this study, white organic electroluminescent devices with microcavity structures were developed. A flexible high‐resolution active‐matrix organic light‐emitting diode display with low power consumption using red, green, blue, and white sub‐pixels formed by a color‐filter method was fabricated. In addition, a side‐roll touch display was developed in combination with a capacitive flexible touch screen. 相似文献
5.
C4+ and S4+-codoped titanium dioxide (TiO2) having a rutile phase was prepared. By doping C4+ and S4+ ions into a TiO2 lattice, the absorption edge of rutile TiO2 powder was largely shifted from 400 to 700 nm. 2-Methylpyridine and methyleneblue were photocatalytically oxidized at high efficiency on C4+ and S4+-doped TiO2 under visible light at a wavelength longer than 5 nm. 相似文献
6.
Outdoor autonomous navigation using SURF features 总被引:1,自引:0,他引:1
In this article, we propose a speeded-up robust features (SURF)-based approach for outdoor autonomous navigation. In this
approach, we capture environmental images using an omni-directional camera and extract features of these images using SURF.
We treat these features as landmarks to estimate a robot’s self-location and direction of motion. SURF features are invariant
under scale changes and rotation, and are robust under image noise, changes in light conditions, and changes of viewpoint.
Therefore, SURF features are appropriate for the self-location estimation and navigation of a robot. The mobile robot navigation
method consists of two modes, the teaching mode and the navigation mode. In the teaching mode, we teach a navigation course.
In the navigation mode, the mobile robot navigates along the teaching course autonomously. In our experiment, the outdoor
teaching course was about 150 m long, the average speed was 2.9 km/h, and the maximum trajectory error was 3.3 m. The processing
time of SURF was several times shorter than that of scale-invariant feature transform (SIFT). Therefore, the navigation speed
of the mobile robot was similar to the walking speed of a person. 相似文献
7.
In negation-limited complexity, one considers circuits with a limited number of NOT gates, being motivated by the gap in our understanding of monotone versus general circuit complexity, and hoping to better understand the power of NOT gates. We give improved lower bounds for the size (the number of AND/OR/NOT) of negation-limited circuits computing Parity and for the size of negation-limited inverters. An inverter is a circuit with inputs x 1,…,x n and outputs ¬ x 1,…,¬ x n . We show that: (a) for n=2 r ?1, circuits computing Parity with r?1 NOT gates have size at least 6n?log?2(n+1)?O(1), and (b) for n=2 r ?1, inverters with r NOT gates have size at least 8n?log?2(n+1)?O(1). We derive our bounds above by considering the minimum size of a circuit with at most r NOT gates that computes Parity for sorted inputs x 1≥???≥x n . For an arbitrary r, we completely determine the minimum size. It is 2n?r?2 for odd n and 2n?r?1 for even n for ?log?2(n+1)??1≤r≤n/2, and it is ?3n/2??1 for r≥n/2. We also determine the minimum size of an inverter for sorted inputs with at most r NOT gates. It is 4n?3r for ?log?2(n+1)?≤r≤n. In particular, the negation-limited inverter for sorted inputs due to Fischer, which is a core component in all the known constructions of negation-limited inverters, is shown to have the minimum possible size. Our fairly simple lower bound proofs use gate elimination arguments in a somewhat novel way. 相似文献
8.
Suppose that some particular link in the Internet is currently
congested.
A natural solution is to try to make packets bypass that link.
This can be done by increasing the cost of that link intentionally,
say from a
1 to a
2, since the Internet uses shortest-path
routing. Unfortunately, however, this often causes temporary loops
for packet traveling, called routing loops. In this paper
we show that routing loops can be avoided by increasing the cost
of the link not directly from a
1 to a
2 but through an
intermediate value, a
3, i.e., from a
1 to a
3 and then
to a
2.
We may need several
intermediate values.
We show that in this case
the greedy strategy,
namely, raising the cost as much as possible in each step,
is optimal. 相似文献
9.
Toshiki Ozaki Tatsuya KotoTam V. Nguyen Hideyuki NakanishiTomohisa Norisuye Qui Tran-Cong-Miyata 《Polymer》2014
Influence of the Trommsdorff–Norrish (T–N) effect on the phase separation of methyl methacrylate (MMA)/poly(ethyl acrylate) (PEA) mixtures undergoing photo-polymerization was examined by a combination of several experimental techniques. By FT-IR spectroscopy, it was found that the polymerization conversion explosively increases at the onset of this T–N effect. The characteristic irradiation time τ at which this effect occurs, strongly depends on the light intensity and gradually shifts to early time as the irradiation intensity increases. The shrinkage of the mixture observed in situ by laser-scanning confocal microscopy exhibits a transition at a particular irradiation time which is slightly longer than the characteristic time τ. By gel permeation chromatography (GPC), it was found that the molecular weight of the resulting PMMA was almost unchanged before τ and suddenly increases about an order of magnitude after the onset of the auto-acceleration effect. Finally, the characteristic length scales of the morphology also quickly increase with irradiation time and are eventually frozen by this T–N effect. These experimental results indicate that the Trommsdorff–Norrish effect plays an important role in the kinetic processes of polymerization-induced phase separation, suggesting an efficient tool to control the morphology of the polymerizing mixture. 相似文献
10.