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971.
港口是城市发展的推进器,城市的诞生、发展和繁荣,大都是伴随着港口的形成、港口经济的发展而发展的。本文通过对清浦港业新城概念性规划设计的介绍,探讨了以港口产业的为核心的港业新城的打造途径,以及其对社会经济发展的推动作用。 相似文献
972.
973.
In this paper, the mixed Navier–Stokes/Darcy problem which describes a fluid flow filtrating through porous media is considered. Based on two-grid discretizations, two local and parallel finite element algorithms for solving this mixed model are proposed. Numerical analysis and experiments are presented to show the efficiency and effectiveness of the local and parallel finite element algorithms. 相似文献
974.
Chong Shen Wencai Du Robert Atkinson Kae Hsiang Kwong 《Wireless Personal Communications》2012,62(2):329-361
We propose a dynamic mobility management framework for Internet Protocol version 6 (IPv6) and policy enforcement enabled heterogenous
wireless networks. Policies and policy rules are defined depending on network infrastructure facilities, service agreements
and negotiation results. Each traffic is coupled with an identifiable traffic flow while the heterogenous interface flow bindings
are regulated by polices. The network selection, flow distribution, handovers and mobility procedures are flexible and we
propose to improve the decision making via Multiple Attributes Decision Making (MADM). Techniques considered in the framework
include the IPv6 based Network Mobility (NEMO), multihoming capability, transparent vertical handovers, horizontal handovers
and dynamic policy enforcement matching process to improve the Quality of Service (QoS), Quality of Experience (QoE) and ubiquitous
connectivity. A experiment testbed and simulation models have been constructed to verify the mobility framework performance
in a heterogeneous WiFi, WiMax and UMTS hybrid environment. 相似文献
975.
Using a password manager is known to be more convenient and secure than not using one, on the assumption that the password manager itself is safe. However recent studies show that most popular password managers have security vulnerabilities that may be fooled to leak passwords without users’ awareness. In this paper, we propose a new password manager, SplitPass, which vertically separates both the storage and access of passwords into two mutually distrusting parties. During login, all the parties will collaborate to send their password shares to the web server, but none of these parties will ever have the complete password, which significantly raises the bar of a successful attack to compromise all of the parties. To retain transparency to existing applications and web servers, SplitPass seamlessly splits the secure sockets layer (SSL) and transport layer security (TCP) sessions to process on all parties, and makes the joining of two password shares transparent to the web servers. We have implemented SplitPass using an Android phone and a cloud assistant and evaluated it using 100 apps from top free apps in the Android official market. The evaluation shows that SplitPass securely protects users’ passwords, while incurring little performance overhead and power consumption. 相似文献
976.
Wei Cheng Yumei Peng Yi Wang Weidong Jiang Yan Long Guangyin Fan 《International Journal of Hydrogen Energy》2021,46(2):2204-2212
Hydrogen evolution from ammonia borane (AB) hydrolysis is of great importance considering the ever-increasing demand for green and sustainable energy. However, the development of a facile and efficient strategy to construct high-performance catalysts remains a grand challenge. Herein, we report an amino-group and space-confinement assisted strategy to fabricate Rh nanoparticles (NPs) using amino-functionalized metal-organic-frameworks (UiO-66-NH2) as a NP matrix (Rh/UiO-66-NH2). Owing to the coordination effect of amino-group and space-confinement of UiO-66-NH2, small and well-distributed Rh NPs with a diameter of 3.38 nm are successfully achieved, which can be served as efficient catalysts for AB hydrolysis at room temperature. The maximum turnover frequency of 876.7 min?1 is obtained by using the Rh/UiO-66-NH2 with an optimal Rh loading of 4.38 wt% and AB concentration of 0.2 M at 25 °C, outperforming most of the previously developed Rh-based catalysts. The catalyst is also stable in repetitive cycles for five times. The high performance of this catalyst must be ascribed to the structural properties of UiO-66-NH2, which enable the formation of small and well-dispersed Rh NPs with abundant accessible active sites. This study provides a simple and efficient method to significantly enhance the catalytic performance of Rh for AB hydrolysis. 相似文献
977.
MQ silicone resins, which represent a broad range of hydrolytic condensation products of monofunctional silane (M) and tetrafunctional silane (Q), were synthesized by reaction of water glass with hexamethyldisiloxane. The optimum reaction time and the optimal reaction temperature is 30 min and 30–40°C, respectively. Concentrated hydrochloric acid is the best one among those catalysts tested. In large-scale experiments (420–1680 mL), the favorable feeding order is catalyst first, and then water glass, the mixture of hexamethyldisiloxane and ethanol last and most MQ silicone resin was observed. The structure of MQ silicone resin was characterized by FT-IR and GPC spectra. The MQ silicone resin shows narrow molecular weight distribution and the number average molecular weight of MQ silicone resin is 2917. The silicone pressure sensitive adhesive prepared from as-synthesized MQ resin has good tack (29#) and 180° peel adhesion (5.630N/20 mm). © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012 相似文献
978.
979.
Changming Zhang Adnan Alhajji Omer R. Koseoglu Zhanggen Huang Li Yang Ronghua Du 《Chemistry and Technology of Fuels and Oils》2012,48(4):331-338
A modified size exchange chromatography method is used to obtain molecular weight distributions, average molecular weight, and other characteristics of heavy oil residues: coal asphalt, petroleum asphalt, vacuum residue oil, and ethylene residue oil. This method can be applied for developing and studying processes involved in hydrogenation of heavy oil residues, road asphalt production, and coal liquefaction. 相似文献
980.
We present particle counting ultrahigh-resolution optical Doppler tomography (pc-μODT) that enables accurate imaging of red blood cell velocities (ν(RBC)) of cerebrovascular networks by detecting the Doppler phase transients induced by the passage of a RBC through a capillary. We apply pc-μODT to image the response of capillary ν(RBC) to mild hypercapnia in mouse cortex. The results show that ν(RBC) in normocapnia (ν(N)?=?0.72?±?0.15?mm/s) increased 36.1%?±?5.3% (ν(H)?=?0.98?±?0.29?mm/s) in response to hypercapnia. Due to uncorrected angle effect and low hematocrit (e.g., ~10%), ν(RBC) directly measured by μODT were markedly underestimated (ν(N) ≈ 0.27?±?0.03?mm/s, ν(H) ≈ 0.37±?0.05?mm/s). Nevertheless, the measured ν(RBC) increase (35.3%) matched that (36.1%?±?5.3%) by pc-μODT. 相似文献