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The catalytic efficiency of iron (II, III) extracted from aquifer materials by DCB(dithionite-citrate-bicarbonate) to promote Fenton-like reaction and the influences of groundwater velocity upon the oxidation efficiency of catalytic reaction were both examined by employing Nitrobenzene (NB) as a model compound at neutral pH (8∼10°C). Fine sand, as the solid catalyst, was selected and simpled as the most-represented aquifer materials in a famous nitrobenzene contaminated site of China based on hydrological analysis. The results indicated that the adsorption to the catalyst changed significantly with the pH value and the sorption isotherm was fitted using the Langmuir model, agent DCB performed the best but also has hysteresis property. The highest removal efficiency could reach 80.2% while the mole ratio of nitrobenzene to H 2 O 2 was 1∶200. On the basis of the findings, one-dimensiona soil column experiments further indicated that groundwater flow velocity could strongly impact the occurrence of extraction agents and aquifer materials so that the effective degradation of NB were repressed due to the lack of extraction reaction time or scavenging effect of hydroxyl radical by H 2 O 2 .

Air sparging (AS) has proven to be one of the most effective means of removing volatile organic compounds in groundwater. The effect of air flow rates on air saturation and radius of influence (ROI) was investigated using a two-dimensional laboratory sand tank. The results showed that increased air flow rate led to higher air saturation and larger ROI, however, at high air flow rates, both increases of air saturation and ROI were not significant. The effect of different air flow rates on chlorobenzene migration and removal in sand tank with a certain hydraulic gradient was also studied. When no air injected, the quantity of chlorobenzene flowing out of sand tank with groundwater accounted for 19.7% of the total chlorobenzene introduced to tank after 130h, these proportions were only 3.6% and 0.9% at air injection rates of 0.1, 0.2m3/h respectively. This reveals AS can efficiently reduce contaminant migration. Through effluent gas sample analysis, the volatilized chlorobenzene was 68.2% and 78.6% of the initial chlorobenzene mass after 130h at air injection rates of 0.1, 0.2m3/h respectively. This reveals AS can effectively remove contaminant in groundwater. These two effects are more obvious when higher air flow rate is used.

The static experiments were constructed to investigate the degradation and enhancement of BTEX by iron reducing microorganism in subsurface environment. The results indicated that the electron acceptor species had significant effects on the degradation of BTEX, When the BTEX concentration was 100mg/L, towad the degradation rate of BTEX and the reduction rate of Fe(III) to decrease in the order akaganeite >goethite> hematite; When the akaganeite was acted as electron donor, BTEX concentration had an impact on its degradation, the degradation of 100mg/L BTEX was relatively better, after reacting 40 days, the degradation rate of benzene, toluene, ethylbenzene, xylene were respectively 46.34%, 58.14%, 59.22%, 69.64%, and the Fe(III) reduction rate was 49.25%; After adding cosubstrate of citric acid, the microbial activity was enhanced, the degradation of BTEX and the reduction of Fe(III) were both improved.

In this paper, the spatial changes of BTEX and redox indicators were studied using a column experiment in laboratory. The spatial variation of concentration of BTEX components in groundwater was exhibited under the different redox conditions. According to different redox indicators, a clear division occurred reflecting the BTEX degradation process in the simulated column, including oxygen reduction zone, nitrate reduction zone, iron reduction zone and sulfate reduction zone and they present in 80–98cm, 60–80cm, 35–60cm and 30–50cm apart from the contaminated source respectively. At the bottom of the column, the methane zone was formed in 0–30cm because of the decreasing of HCO3-.

Based on a Lyapunov function, the global stability of Internet network congestion control algorithm (NCCA) is analyzed. The global asymptotical stability (GAS) of delayed Internet NCCA is discussed by means of Lyapunov-Razumikhin's theory. We obtain a criterion for the GAS of the NCCA in the general topology structure network with heterogeneous delays. Computer simulations are performed to show the efficiency of the stability criterion.

A novel 5-DOF PMT (parallel machine tool) is proposed, which has five driving limbs and a passive limb. It can perform three translational DOFs (degrees of freedom) and two rotational DOFs. The passive limb can act as not only a constraint chain, but also a measuring chain. Multi-axis simultaneous control must be performed and the mapping transformation of motion from the virtual to actual axis is the core of the control algorithms. The control algorithms, such as coarse interpolation of the tool path, the mapping transformation from the CL (cutter location) data to the length of driving axis, velocity control of the driving axis and pose measuring method of the tool, are analyzed in detail. The CNC system software based on the algorithms has been developed and applied to the novel 5-DOF PMT in our laboratory. The machining experiments are made and the better machining performance is achieved.

A new type of 5-UPSIPRPU Prirallel Machine Tool is proposed. It has a PRPU measuring limb with excellent kinematic characteristics, which can measinre the pose of the moving platform. It's convenient to calibrate the machine tool and the cost of calibration is decreased greatly. The PRPU limb makes it possible for realizing the closed-loop control at low cost. This paper presents a method, which has been proved by the experiment, of calibrating the PRPU limb.

This paper studies one newly-emerging area of data mining-ordered information table. This paper uses rough set theory to mine rules in ordered information table. Compared with traditional rough set theory based methods, applications in ordered information table deal with ordering objects instead of classifying them, in which objects are ordered both by descriptive and overall attributes, and rules to be mined are actually the association between them. In order to mine rules of such form, this paper generalizes rough set theory under the core relation in ordered information table partial order. Subsequent experiments show that efficiency of the method in this paper is higher than that of previous approaches.