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1.
Jun-ichi Imura 《Automatic Control, IEEE Transactions on》2003,48(11):1926-1935
The well-posedness problem (existence and uniqueness of solutions) of a class of multi-modal piecewise affine systems is addressed, where binary-switches individually act under autonomous switching. First, a new transition rule on the discrete state, called the switch-based transition rule, is introduced and some relations with the mode-based transition rule are discussed. Next, a sufficient condition for such a multi-modal system to be well-posed for all external inputs is derived in terms of well-posedness of its subsystems of lower complexity "bimodal systems". Finally, an easily checkable condition for the bimodal system to be well-posed for all external inputs is given, which consequently allows us to algebraically determine well-posedness of the multi-modal systems in question. 相似文献
2.
Atsuyoshi Nakamura Jun-ichi Takeuchi Naoki Abe 《Annals of Mathematics and Artificial Intelligence》1998,23(1-2):53-82
We consider a variant of the ‘population learning model’ proposed by Kearns and Seung [8], in which the learner is required
to be ‘distribution-free’ as well as computationally efficient. A population learner receives as input hypotheses from a large
population of agents and produces as output its final hypothesis. Each agent is assumed to independently obtain labeled sample
for the target concept and output a hypothesis. A polynomial time population learner is said to PAC-learn a concept class,
if its hypothesis is probably approximately correct whenever the population size exceeds a certain bound which is polynomial,
even if the sample size for each agent is fixed at some constant. We exhibit some general population learning strategies,
and some simple concept classes that can be learned by them. These strategies include the ‘supremum hypothesis finder’, the
‘minimum superset finder’ (a special case of the ‘supremum hypothesis finder’), and various voting schemes. When coupled with
appropriate agent algorithms, these strategies can learn a variety of simple concept classes, such as the ‘high–low game’,
conjunctions, axis-parallel rectangles and others. We give upper bounds on the required population size for each of these
cases, and show that these systems can be used to obtain a speed up from the ordinary PAC-learning model [11], with appropriate
choices of sample and population sizes. With the population learner restricted to be a voting scheme, what we have is effectively
a model of ‘population prediction’, in which the learner is to predict the value of the target concept at an arbitrarily drawn
point, as a threshold function of the predictions made by its agents on the same point. We show that the population learning
model is strictly more powerful than the population prediction model. Finally, we consider a variant of this model with classification
noise, and exhibit a population learner for the class of conjunctions in this model.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
3.
Noritsugu Hashimoto Seiji Niijima Jun-ichi Inagaki 《Journal of the European Ceramic Society》2009,29(14):3039-3043
Solid oxide fuel cells (SOFCs) are very attractive for their high energy conversion efficiency and low emissions. Generally, a supported layer of SOFCs is fabricated by tape casting, using an organic solvent. Recently, a slurry based on water instead of an organic solvent has been sought in order to avoid environmental pollution. In this study, the anode of SOFCs was fabricated by aqueous tape casting, and the electrolyte and the cathode were deposited by screen printing. The I–V characteristics of the cell thus obtained were evaluated. As a result, an 80 mm diameter-sized cell with a power density of 0.33 W/cm2 at 800 °C was successfully fabricated by controlling sintering conditions. 相似文献
4.
Tomoya Hasegawa Mikako Ito Satoru Hasegawa Masaki Teranishi Koki Takeda Shuto Negishi Hiroshi Nishiwaki Jun-ichi Takeda Tyler W. LeBaron Kinji Ohno 《International journal of molecular sciences》2022,23(5)
Molecular hydrogen ameliorates pathological states in a variety of human diseases, animal models, and cell models, but the effects of hydrogen on cancer have been rarely reported. In addition, the molecular mechanisms underlying the effects of hydrogen remain mostly unelucidated. We found that hydrogen enhances proliferation of four out of seven human cancer cell lines (the responders). The proliferation-promoting effects were not correlated with basal levels of cellular reactive oxygen species. Expression profiling of the seven cells showed that the responders have higher gene expression of mitochondrial electron transport chain (ETC) molecules than the non-responders. In addition, the responders have higher mitochondrial mass, higher mitochondrial superoxide, higher mitochondrial membrane potential, and higher mitochondrial spare respiratory capacity than the non-responders. In the responders, hydrogen provoked mitochondrial unfolded protein response (mtUPR). Suppression of cell proliferation by rotenone, an inhibitor of mitochondrial ETC complex I, was rescued by hydrogen in the responders. Hydrogen triggers mtUPR and induces cell proliferation in cancer cells that have high basal and spare mitochondrial ETC activities. 相似文献
5.
In the present study, K2S and Bi2S3 were used as additives in electrolytes and electrodes, respectively. The effects of these additives on the electrochemical properties of nano-sized Fe2O3-loaded carbon electrodes were investigated using cyclic voltammetry (CV), galvanostatic cycling performance and scanning electron microscopy (SEM), along with electron dispersive spectroscopy (EDS). The results showed that both K2S and Bi2S3 significantly reduced hydrogen evolution and benefited the Fe2O3-loaded carbon electrode, such as by retarding passivation and improving the discharge capacity. The effects of metal sulfide additives depended on the carbon used. For Bi2S3 additive, all carbons provided larger capacities than acetylene black (AB) while AB gave greater capacity than other carbons when K2S was used. 相似文献
6.
Kiyoaki Imoto Kohshin Takahashi Takahiro Yamaguchi Teruhisa Komura Jun-ichi Nakamura Kazuhiko Murata 《Solar Energy Materials & Solar Cells》2003,79(4):459-469
Here, we reported that a new carbon electrode prepared with an activated carbon was superior to a Pt sputtered electrode as the counter electrode of dye-sensitized solar cells. The photovoltaic performance was largely influenced by the roughness factor of carbon electrode. The open-circuit voltage increased by about 60 mV using the carbon counter electrode compared to the Pt counter electrode because of positive shift of the formal potential for I3−/I− couple. 相似文献
7.
Avidin-containing polyelectrolyte microcapsules were prepared by a layer-by-layer deposition technique and uptake and release of biotin-labelled fluorescein (b-FITC) was studied. The polyelectrolyte microcapsules were prepared by coating the surface of calcium carbonate (CaCO3) microparticles containing avidin-poly(styrene sulfonate) (PSS) conjugate, followed by dissolution of CaCO3 core in an ethylenediaminetetraacetic acid solution. Release of avidin from the microcapsules was markedly suppressed due to formation of a high molecular weight of avidin-PSS conjugate in the microcapsules. The uptake of b-FITC into the microcapsules was highly enhanced through a strong binding of b-FITC to avidin, as compared to the uptake into avidin-free microcapsules. Release of b-FITC from the microcapsules was accelerated upon addition of biotin, 2-iminobiotin, or lipoic acid in the solution due to the competitive binding of the additives to the binding site of avidin. 相似文献
8.
Hideo Sawada Sachiko HataNobuhito Kawasaki Jun-ichi IidzukaKentaro Tokugi Jun KyokaneTomomi Maekawa Tokuzo Kawase 《Polymer》2002,43(3):1035-1038
New fluoroalkyl end-capped fullerene cooligomers were prepared by the reactions of fluoroalkanoyl peroxides with fullerene and comonomers such as acryloylmorpholine, N,N-dimethylacrylamide and acrylic acid. These fluorinated fullerene cooligomers were easily soluble in water and common organic solvents, and were able to reduce the surface tensions of both water and benzene, quite effectively. Additionally, these fullerene cooligomers were found to form a stable monomolecular film at the air-water interface, and the modified polystyrene surface treated with these cooligomers was shown to have a strong hydrophilicity with good oil repellency. 相似文献
9.
Catalytic Friedel–Crafts acylation of heteroaromatics has been achieved using metal triflates as catalysts. While conventional Friedel–Crafts acylation often requires the use of more than stoichiometric amounts of aluminum chloride, metal triflates such as tin(II) triflate, scandium triflate, and gallium triflate, etc. have enabled efficient acylation reactions by catalytic use. 相似文献
10.
Yusaku Takita Jun-ichi Moriyama Hiroyasu Nishiguchi Tatsumi Ishihara Fusakazu Hayano Tetsuo Nakajo 《Catalysis Today》2004,88(3-4):103-109
Activity for hydrolysis of CCl2F2 (CFC12) on various metal sulfate was investigated. Zr(SO4)2 was found to be the most active while FeSO4, Cr2(SO4)3, Al2(SO4)3, La2(SO4)3 and Ce2(SO4)3 had intermediate activity. MnSO4, CoSO4, and MgSO4 showed low activity and SrSO4, CaSO4, and BaSO4 had even less activity. The major carbon containing product was CO2 and small amount of CClF3 and CO were formed over several sulfates. The crystal structure of the sulfates was stable during decomposition of CCl2F2, and the conversion reached a steady state after initial decrease at 275 °C over Zr(SO4)2 catalyst. The concentration of surface hydroxyl was larger than that over AlPO4-based catalysts and a reaction mechanism similar to that over AlPO4-based catalysts was proposed. 相似文献