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71.
A phenolic resin carbon containing nickel particles, ~100 μm diam., was graphitized to 2773K for 1 h. This treatment created within the specimen three structural components known as graphitic (G), turbostratic (Ts) and matrix (A). The graphitized carbon was oxidized by carbon dioxide, HNO3-H2SO4 mixed acid and Simon's reagent and topographical changes were monitored by SEM. The CO2 gasified preferentially the Ts-component to produce fissures mainly at the interface with the A- andG-component. The mixed acid reacted preferentially with the G- andTs-components, the Simon's reagent reacting significantly only with the G-component. The mineral matter of metallurgical coke can act as a graphitization catalyst similar to nickel particles. Hence, the development of structural components within the metallurgical coke followed by gasification by carbon dioxide may cause weakening of the coke at the interfaces of components. 相似文献
72.
Silver acetate dissolved in quinoline was mixed thoroughly with the spinnable isotropic petroleum pitch dissolved in the same solvent. After removing the quinoline, the resulting pitch was spun, stabilized, carbonized, and finally activated at 900°C under a stream of steam. The fiber with 33 wt% yield after activation contained 0.63 wt% of fine silver particles and showed N2-BET specific surface area of 740 m2/g. It showed antibacterial activity against Staphylococcus aureus and Escherichia coli, before and after soaking in flowing tap water for 20 days. How to improve spinnability of the pitch containing silver acetate and how to increase the specific surface area effectively by the activation process are problems remaining to be solved. 相似文献
73.
A New Formulation Approach for Location-Routing Problems 总被引:1,自引:1,他引:0
A Location-Routing Problem (LRP) combines two difficult problems, facility location and vehicle routing, and as such it is inherently hard to solve. In this paper, we propose a different formulation approach than the common arc-based product-flow (Arc-BPF) approach in the literature. We associate product amounts to the nodes of the network resulting in a node-based product-flow (Node-BPF) formulation. Our main objective is to develop LRP models with fewer constraints and variables, which can be solved more efficiently. To introduce the proposed approach, we reformulate a complex four-index Arc-BPF LRP model from the literature as a three-index Node-BPF model, which computationally outperforms the former. We then introduce a heuristic method. 相似文献
74.
Artificial Life and Robotics - The number of automobile accidents still exceeds 300,000 as of 2020 in Japan. People have paid attention to the automatic driving technology as one technology for... 相似文献
75.
Akiko Hamada Makoto Kobayashi Katsushi Matsuoka Masato Suzuki Junya Osuo Naoko Ashikawa Akio Sagara Yuji Hatano Yasuhisa Oya Kenji Okuno 《Fusion Engineering and Design》2012,87(7-8):1214-1217
The behavior of hydrogen retention and the change of chemical states of boron film exposed to hydrogen plasma in LHD were investigated. The sample was prepared in LHD, and atomic concentrations for the boron film after hydrogen plasma exposure were changed from 75% for boron, 15% for carbon and 8% for oxygen to 53%, 18% and 22%, respectively. BC bond was a major chemical state of the boron film after hydrogen plasma exposure, although abundance of BB bond was the highest before the plasma exposure. Total hydrogen retention measured by TDS was evaluated to be 1.7 × 1020 H m?2, and the retentions of hydrogen as BHB, BH and BCH bonds were, respectively, 4.8 × 1019, 7.2 × 1019 and 5.2 × 1019 H m?2. It was concluded that the hydrogen retention could be estimated by taking account not only of chemical states of impurities, but also of hydrogen depth profile. 相似文献
76.
Heiko Brennenstuhl Miroslava Didiasova Birgit Assmann Mariarita Bertoldi Gianluca Molla Sabine Jung-Klawitter Oya Kuseyri Hübschmann Julian Schrter Thomas Opladen Ritva Tikkanen 《International journal of molecular sciences》2020,21(22)
Succinic semialdehyde dehydrogenase deficiency (SSADHD) is a rare, monogenic disorder affecting the degradation of the main inhibitory neurotransmitter γ-amino butyric acid (GABA). Pathogenic variants in the ALDH5A1 gene that cause an enzymatic dysfunction of succinic semialdehyde dehydrogenase (SSADH) lead to an accumulation of potentially toxic metabolites, including γ-hydroxybutyrate (GHB). Here, we present a patient with a severe phenotype of SSADHD caused by a novel genetic variant c.728T > C that leads to an exchange of leucine to proline at residue 243, located within the highly conserved nicotinamide adenine dinucleotide (NAD)+ binding domain of SSADH. Proline harbors a pyrrolidine within its side chain known for its conformational rigidity and disruption of protein secondary structures. We investigate the effect of this novel variant in vivo, in vitro, and in silico. We furthermore examine the mutational spectrum of all previously described disease-causing variants and computationally assess all biologically possible missense variants of ALDH5A1 to identify mutational hotspots. 相似文献
77.
A novel self-mending polymer with high thermal stability is developed based on the DA reaction between anthracene and maleimide. A network polymer, PEAA2M3 is prepared by the DA reaction of anthryl-telechelic poly(ethylene adipate) and a tris-maleimide. While the forward DA (addition) reaction is favored at room temperature, the reverse DA (dissociation) reaction is induced by mechanical stress. This mechanochemical reversibility allows the autonomous mending of cracks in PEAA2M3 at room temperature. It is well known that the thermal dissociation of the DA reaction occurs only at very high temperatures at which organic polymers degrades significantly. Therefore, thermal stability is successfully combined with self-mending ability in PEAA2M3. 相似文献
78.
Tokumitsu T. Piernas B. Oya A. Sakai K. Hasegawa Y. 《Microwave and Wireless Components Letters, IEEE》2005,15(5):318-320
Three-dimensional (3-D) microwave monolithic integrated circuit (MMIC) technology, that incorporates slits in the ground metal, was applied to K-band low noise amplifier (LNA) and I/Q mixer to provide a low cost solution for various K-band receivers such as for P-to-P radio, WLAN, and UWB sensors. The LNA incorporates a quasicoplanar stub in the input-matching network, improving the noise figure by 1 dB. This low-noise amplifier (LNA) exhibits a noise figure of 2.5 dB with an associated gain of 16 dB and an area of 0.75/spl times/0.65 mm/sup 2/. The I/Q resistive mixer incorporates a broadside 3-dB coupler with a 22-/spl mu/m-wide slit in the ground metal beneath the coupled thin-film micro-strip (TFMS) lines (patent pending). The insertion loss of the 3 dB coupler is 0.75 dB. The I/Q mixer exhibits a conversion loss of less than 14 dB at 0.1-2.0GHz IF frequencies for 2-dBm local input power. These LNA and mixer potentially make it easier to integrate receiver functions in a die. 相似文献
79.
Axial compressive behaviour of reinforcing fibres and interphase in glass fibre/epoxy resin composites were examined. Axial compressive strengths of glass fibres were evaluated by the tensile recoil method. The effects of silane-based coupling surface treatment agent on the fibre compressive strengths were investigated. The glass fibres showed higher compressive strengths when coated by the surface treatment. Interphase behaviour was also investigated by means of the single-fibre embedded compressive test. The particular stress and strain distributions inside the specimen were examined by a three-dimensional finite element analysis. The parameter interfacial transmissibility instead of the conventional critical fibre length theory was introduced as an index of interfacial properties. This parameter was useful to estimate the interfacial properties at the elastic state apart from the complicated critical state. It was confirmed that the surface treatment improved the glass/epoxy interphase under axial compressive load. 相似文献
80.
This paper considers the scheduling problems arising in two- and three-machine manufacturing cells configured in a flowshop
which repeatedly produces one type of product and where transportation of the parts between the machines is performed by a
robot. The cycle time of the cell is affected by the robot move sequence as well as the processing times of the parts on the
machines. For highly flexible CNC machines, the processing times can be changed by altering the machining conditions at the
expense of increasing the manufacturing cost. As a result, we try to find the robot move sequence as well as the processing
times of the parts on each machine that not only minimize the cycle time but, for the first time in robotic cell scheduling
literature, also minimize the manufacturing cost. For each 1-unit cycle in two- and three-machine cells, we determine the
efficient set of processing time vectors such that no other processing time vector gives both a smaller cycle time and a smaller
cost value. We also compare these cycles with each other to determine the sufficient conditions under which each of the cycles
dominates the rest. Finally, we show how different assumptions on cost structures affect the results. 相似文献