Nankai University

About: Nankai University is a education organization based out in Tianjin, China. It is known for research contribution in the topics: Catalysis & Adsorption. The organization has 42964 authors who have published 51866 publications receiving 1127896 citations. The organization is also known as: Nánkāi Dàxué.

Novel Superhard Carbon: C-Centered Orthorhombic C 8

Abstract: A novel carbon allotrope of C-centered orthorhombic ${\mathrm{C}}_{8}$ ($\mathrm{Cco}\mathrm{\text{\ensuremath{-}}}{\mathrm{C}}_{8}$) is predicted by using a recently developed particle-swarm optimization method on structural search. $\mathrm{Cco}\mathrm{\text{\ensuremath{-}}}{\mathrm{C}}_{8}$ adopts a $s{p}^{3}$ three-dimensional bonding network that can be viewed as interconnected $(2,2)$ carbon nanotubes through 4- and 6-member rings and is energetically more favorable than earlier proposed carbon polymorphs (e.g., $M$ carbon, $\mathrm{bct}\mathrm{\text{\ensuremath{-}}}{\mathrm{C}}_{4}$, $W$ carbon, and chiral ${\mathrm{C}}_{6}$) over a wide range of pressures studied (0--100 GPa). The simulated x-ray diffraction pattern, density, and bulk modulus of $\mathrm{Cco}\mathrm{\text{\ensuremath{-}}}{\mathrm{C}}_{8}$ are in good accordance with the experimental data on structurally undetermined superhard carbon recovered from cold compression of carbon nanotube bundles. The simulated hardness of $\mathrm{Cco}\mathrm{\text{\ensuremath{-}}}{\mathrm{C}}_{8}$ can reach a remarkably high value of 95.1 GPa, such that it is capable of cracking diamond.

Scheduling the maintenance on a single machine

Abstract: This paper considers a single machine scheduling problem with preventive maintenance. In many cases, a machine must be maintained after it continuously works for a period of time. But most papers in the literature ignore non-availability of the machine. For this reason, this paper studies the problem of scheduling processing of jobs and maintenance of machine simultaneously. The objective is to minimise total completion time of jobs. The problem is proved to be NP-hard in the strong sense. Three heuristic algorithms and a branch and bound algorithm are proposed. Computational experiments are done to evaluate the effectiveness of the algorithms.

Bioelectrochemical stimulation of petroleum hydrocarbon degradation in saline soil using U-tube microbial fuel cells

Abstract: Bioremediation is a cost-effective and eco- friendly approach to decontaminate soils polluted by petro- leum hydrocarbons. However, this technique usually requires a long time due to the slow degradation rate by bacteria. By applying U-tube microbial fuel cells (MFCs) designed here, the degradation rate of petroleum hydro- carbons close to the anode (<1 cm) was enhanced by 120% from 6.9 � 2.5% to 15.2 � 0.6% with simultaneous 125 � 7 C of charge output (0.85 � 0.05 mW/m 2 ,1 kV )i n the tested period (25 days). Hydrocarbon fingerprint analy- sis showed that the degradation rate of both alkanes and polycyclic aromatic hydrocarbons (PAHs) was accelerated. The decrease of initial water content from 33% to 28% and 23% resulted in a decrease on charge output and hydrocar- bon degradation rate, which could be attributed to the increase of internal resistance. A salt accumulation was observed in each reactor due to the evaporation of water from the air-cathode, possibly inhibited the activity of exoelectrogenic bacteria (EB) and resulted in the elimination of the current at the end of the tested period. The number of hydrocarbon degradation bacteria (HDB) in soil close to the anode increased by nearly two orders of magnitude in the MFC assisted system (373 � 56 � 10 3 CFU/g-soil) than that in the disconnected control (8 � 2 � 10 3 CFU/g-soil), pro- viding a solid evidence for in situ biostimulation of HDB growth by colonization of EB in the same system. Biotechnol. Bioeng. 2012;109: 426-433. 2011 Wiley Periodicals, Inc.