骨水泥混合与注射一体化装置行经皮椎体成形术治疗椎体压缩性骨折

目的探讨骨水泥混合与注射一体化装置行经皮椎体成形术治疗椎体压缩性骨折的操作技术、临床疗效.方法 2002～2004年间共计治疗了108例诉有严重疼痛的椎体压缩性骨折患者,其中骨质疏松性压缩性骨折85例,椎体恶性肿瘤31例.穿刺入路采用双侧椎弓根穿刺法,所有患者均在透视监视下双侧注射聚甲基丙烯酸甲酯( polymethylmethacrylate,PMMA),注射设备为骨水泥混合与注射一体化装置.术后随访患者6个月.结果共计注射116个椎体(腰椎69个,胸椎47个),双侧穿刺和骨水泥注射成功率100%,99     

New developments in the theory and modeling of mercury oxidation and binding on activated carbons in flue gas

Recent advances in the mechanistic understanding of mercury oxidation on a carbon surface in flue gas are reviewed in this paper. Theoretical calculations were performed to determine whether the energetics are feasible for a proposed detailed model for oxidative addition of elemental mercury on a carbon edge structure. The results of the calculation show that mercury complexation with a carbenium ion formed at a zigzag edge carbon has a small positive ΔG, but attack of chloride on the complex will proceed with negative ΔG. The energetics rule out a direct covalent bond formation between mercury and the carbenium ion. Alternative concerted reaction models and double-charged models for the mechanism are also feasible but have not yet been computed.     

How far have we been? —Summary of investigations on rotating cavity at IDG, RWTH Aachen University

Annular cavities are found inside rotor shafts of turbomachines with an axial or radial throughflow of cooling air, which influences the thermal efficiency and system reliability of the gas turbines. The flow and heat transfer phenomena in those cavities should be investigated in order to minimize the thermal load and guarantee the system reliability. An experimental rig is set up in the Institute of Steam and Gas Turbines, RWTH Aachen University, to analyze the flow structure inside the rotating cavity with an axial throughflow of cooling air. The corresponding 3D numerical investigation is conducted with the in-house flow solver CHTflow, in which the Coriolis force and the buoyancy force are implemented in the time-dependent Navier-Stokes equations. Both the experimental and numerical results show that the whole flow structure rotating slower than the cavity rotating speed. The flow passing the observation windows in the experimental and numerical results indicates the quite similar trajectories. The computed sequences and periods of the vortex flow structure correspond closely with those observed in the experiment. Furthermore, the numerical analysis reveals a flow pattern changing between single pair, double pair, and triple pair vortices. It is suggested that the vortices inside the cavity are created by the gravitational buoyancy force in the investigated case, while the number and strength of the vortices are controlled mainly by the Coriolis force.     

Superior N- and P-MOSFET scalability using carbon co-implantation and spike annealing

We report the simultaneous improvement of both on- and off-properties for n- and p-channel MOSFETs by means of carbon co-implantation at extension level, using conventional spike annealing. For the first time, spike-annealed NFETs with phosphorus-implanted source/drain extensions (SDE) are shown to outperform conventional As-implanted devices in the deca-nanometric range. Parameters such as on-current, drain-induced barrier lowering (DIBL), external resistance (R_EXT) vs. effective channel length (L_eff) trade-off are examined. To obtain the full benefit of carbon co-implantation, we recommend adjusting pocket, highly doped drain (HDD) and spacer parameters.     

Performance of very small wastewater treatment plants with pronounced load variations.

The operation of very small biological wastewater systems is strongly influenced by the patterns of wastewater generation. The absence of people in the connected building(s) during holidays or off-season leads to a system underload, other circumstances however may lead to an overload. Experiments have been carried out to display the effects of no-feed conditions on activated sludge biomass and its microbial activity during a 24 hour period after re-feeding. The decrease of the biomass during idle periods can be modelled by a first order equation. The initial specific oxygen uptake rate (OUR) of the remaining biomass decreased with the duration of the preceding no-feed sequence. Four different laboratory-scale treatment plants were operated to demonstrate the system performance when re-started after a break period of 24 and 52 days respectively. The effluent concentration after a break of 52 days had not been sufficient as compared to the discharge requirements given by German laws. In addition a full scale trickling filter was monitored, while the connected building accommodated a maximum of 40 guests interrupted by times with no guest at all. Conclusions are drawn from the experimental results and from literature, giving some hints on how to manage the impacts of varying loads at very small wastewater treatment plants.