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Aspheric lens of Zinc sulfide is widely used in infrared, but it is always formed by polishing with low efficiency, ductile regime grinding aspheric surface of hot-pressed zinc sulfide is studied to reduce time-consuming of polishing. The results of orthogonal grinding experiments demonstrate that the depth of grinding is the main influencing factor on ductile regime removal mechanisms and surface roughness Ra values which decrease with decreasing depth of grinding, and the optimal value is 7.6nm, the steady ductile regime removal mechanisms appears when depth of grinding is below 0.4μm. With diamond wheel by grain size of D20/30, machining parameters on the basis of orthogonal grinding experiments, the aspheric surface cross grinding experiments show that ductile regime removal is obtained only in little center areas of aspheric surface, most of aspheric surface is in brittle regime. Then, the ductile regime aspheric surface with roughness of 20.1nm is observed by cross grinding of diamond wheel with grain size of D4/8.

Microstructured optical elements made of glass are generally replicated by hot pressing with super-hard materials, such as binderless tungsten carbide (WC) and precision ceramic. However, in grinding of microstructures, problems frequently occur in terms of rough ground surface, chipping and rounding of micro-structures edges when compared to conventional grinding. In order to overcome these technological constraints, a promising precision grinding method for microstructured surfaces that applies ultrasonic vibration to improve the surface quality, and protect the edges and tips of microstructured surfaces is presented. The experimental investigation of ultrasonic vibration assisted grinding of microstructures on binderless WC is researched. The effects of ultrasonic vibration on surface roughness, form accuracy and edge radius were analyzed. The morphology of surface and array edges was examined with a scanning electron microscope (SEM), while the surface roughness was measured by a laser interferometer. And a contact probe profilometer was used to assess the form of array and radius of microstructured edges. Experimental results showed that the application of ultrasonic vibration leads to significant improvements of the surface roughness and edges of microstructures compared with traditional precision grinding processes. A micro cylinder lens array of binderless WC with surface roughness of 78nm and edge radius of less than 1μm was obtained. The novel grinding method is feasible and applicable in machining higher form accuracy microstructures.

The emission of volatile organic compounds (VOCs) from wastewater treatment plants (WWTPs) is becoming an environmental issue of increasing concern. As biological treatment has been considered as one important approach for VOC removal, lab-scale batch experiments were conducted in this study to investigate the fates of four chlorinated hydrocarbons, including chloroform, carbon tetrachloride, trichloroethylene (TCE), and tetrachloroethylene (PERC), in the biological treatment processes with respect to the effects of aeration and sludge addition. The VOC concentrations in the phases of air, water, and sludge under four simulated treatment stages (the first sedimentation, the forepart and rear part of aerobic biological treatment, and the second sedimentation) were analyzed. The results were used to understand the three-phase partitioning of these compounds and to estimate their potentials for volatilization and biological sorption and degradation in these technologies with the concept of fugacity. It was observed that the VOCs were mainly present in the water phase through the experiments. The effects of aeration or sludge addition on the fates of these VOCs occurred but appeared to be relatively limited. The concentration distributions of the VOCs were well below the reported partitioning coefficients. It was suggested that these compounds were unsaturated in the air and sludge phases, enhancing their potentials for volatilization and biological sorption/degradation through the processes. However, the properties of these chlorinated VOCs such as the volatility, polarity, or even biodegradability caused by their structural characteristics (e.g., the number of chlorine, saturated or unsaturated) may represent more significant factors for their fates in the aerobic biological treatment processes. These findings prove the complication behind the current knowledge of VOC pollutions in WWTPs and are of help to manage the adverse impacts on the environment and public health by the VOCs from these particular sources.

China has been going through urbanization, and foreign experiences show that urbanization would finally lead to integrated planning and development of region. In regional planning, traffic network is an important aspect, which affects the impact of cities. However, in traditional accessibility analysis, only traffic lines are taken into consideration, while the influence of stations is ignored. This lead to the actual problems that traffic facilities cannot play the roles designed in regional planning when they are really constructed. Therefore, firstly, two rank traffic networks system are proposed, and different traffic networks with the normalization costs are combined to analyse the accessibility of the cities. Secondly, a new accessibility analysis method to get arrival domain for a city is proposed, which take not only the traffic lines but the traffic stations into consideration. Finally, the Jing-Jin-Ji Region is taken as an instance to show the effect of the new method.

Femtosecond laser micromachining technology shows abroad application background in the field of micro manufacturing due to its unique advantages, especially for micromachining of ultrahard materials such as Silicon carbide (SiC) ceramic. The femtosecond laser micromachining system was set up, by using the system, effects of scanning velocity and laser pulse energy on quality of micromachined features were evaluated. The optimized technological parameter was obtained as 8mW, 1mm/s with 1kHz repetition frequency respectively on the basis of the morphological characteristics and microstructure accuracy. Besides, V-shaped cavity of 300μm depth and 120°angle was generated with layer-by-layer scan machining. Thus femtosecond laser micromachining technology is an effective method for hard and brittle materials precision processing.

In this study, a lab-scale bioreactor experiment was conducted to investigate the fates of three aromatic hydrocarbons (benzene, toluene, and xylenes) in wastewater treatment processes, with respect to the differences among the species, together with the effects of aeration and the presence of activated sludge. The concentrations of the volatile organic compounds (VOCs) in the phases of air, water, and activated sludge in the bioreactor were analyzed to determine the respective chemical activities and to predict the possible transferring potentials of the VOCs among the three phases. Given appreciable levels of the VOCs being absorbed from the wastewater treatment plants (WWTPs) and their volatility, the directions of the transfers for these VOCs were from activated sludge to water and from water to air, indicating the importance of volatilization for the fates of VOCs in this reactor. The presence of activated sludge in the bioreactor had a positive effect on the transfers of the VOCs from air to water and from water to sludge, particularly for those VOCs with large octanol-water partition coefficients (KOW). The effect of aeration on the fates of the VOCs was affected by factors including the Henry’s law coefficients and KOW values of the VOCs, and the presence of activated sludge in the system. For the VOCs with large Henry’s law coefficients and small KOW values, aeration reduced the concentration of the VOCs in the air and water phases more significantly, resulting in positive and negative impacts on the volatilization and biosorption/biodegradation of the VOCs in WWTPs, respectively, which was unexpected based on the design of the WWTPs for VOC removal.

In order to quantitatively identify sources of nitrate pollution in Beijing urban area and provide effective guidance for relevant departments to control the pollution of Beijing rivers, δ¹⁵N-NO₃⁻ and δ¹⁸O-NO₃⁻ isotope tracing method was used to analyze the composition of nitrogen and oxygen stable isotopes from nitrate in Beijing urban river. Besides, stable isotope mixing model was adopted to track nitrogen sources of nitrate in Beijing urban rivers and the contribution rates of respective pollution sources were evaluated. The results showed that: (1) NO₃⁻-N pollution was the main inorganic nitrogen pollution in Beijing rivers and pollution of downstream was more serious than that of upstream. (2) δ¹⁵N-NO₃⁻ in Beijing urban surface rivers was in range of 6.26 per thousand-24.94 per thousand, while δ¹⁸O-NO₃⁻ ranged -0.41 per thousand-11.74 per thousand; δ¹⁵N-NO₃⁻ increased from upstream to downstream along the flow of the surface water. (3) The nitrate pollution composition of Beijing rivers could be gained from the stable isotope mixing model. The average contribution rates of manure and sewage, soil nitrate and atmospheric deposition were 61.2%, 31.5% and 7.3%, respectively.

The rotor mass imbalance is main reason of rotating mechanical vibration. A new dynamic balance weighting method for single-disk rotor system based on phase difference mapping is presented. Firstly, the influence coefficient method and its characteristics are analyzed in detail. Secondly, the equivalent phase difference mapping relationship between incentive and vibration response for single-disk rotor system is proved by differential equations and Laplace transform theory. Finally, a specific application instance is showed. The new method is simple and easy to peel the phase coupling relationship between incentive and response, which can be used to guide dynamic balance weighting for single-disk rotor system on site.

To reduce the production cost of polyhydroxyalkanoates (PHA) and disposal amount of excess sludge simultaneously, volatile fatty acids (VFAs) from alkaline excess sludge fermentation was used as carbon sources to synthesize PHA by unenriched mixed cultures. Released phosphorus and residual ammonium in the fermentative VFAs was controlled by adding magnesium to form struvite precipitation. Four VFAs liquids obtained was used to test the influence of initial carbon load and carbon to nitrogen ratio (C:N ratio) on the VFAs uptake rate, PHA storage rate and biomass growth rate. Results show that higher initial carbon substrate load results in relatively higher VFAs uptake rate and higher PHA storage rate, while higher initial C:N ratio results in relatively lower biomass growth rate from VFAs. VFAs generated from thermophilic alkaline sludge fermentation were a suitable carbon source for PHA production by mixed cultures.

This paper aims to develop a laser assisted grinding process capable of manufacturing micro features in high strength materials. A diode laser with wavelength 808 nm was set on a precision grinding machine. Micro grooves were fabricated on high strength materials including silicon nitride and aluminium oxide by using the laser assisted grinding process, i.e. laser pre-heat workpiece flowed by micro grinding. The experimental results showed that the laser assisted grinding process resulted in deeper grooves due to thermal expansion of workpiece materials caused by laser heating. However, the machined surface roughness was more consistently better than that obtained using solo grinding process and applying coolant. No subsurface damage was observed in the SEM images of cross sections of the machined workpieces when laser assisted grinding process was used.

The swelling effect is an important factor to affect surface generation in SPDT. Face cutting experiments are conducted for copper, aluminum alloy and electroless nickel phosphorus to analyze the swelling effect including the relationship between it and cutting parameters as well as effect of material property. How the material swelling affects surface roughness is also studied in this paper. The results indicate that the swelling effect is influenced by spindle speed and material property more remarkably when compared to feed rate and depth of cut. In addition, a softer and more ductile material will lead to a stronger material recovery, a lower swelling proportion, a lower tool mark height and a smoother machined surface. The result reveals that the swelling effect must be considered when predicting surface roughness in SPDT

The efficiency and sustainability of microbial fuel cell (MFC) are heavily dependent on the cathode performance. We show here that the use of graphite fiber brush (GBF) together with graphite granules (GGs) as a basal material for biocathode (MFC reactor type R1) significantly improve the performance of a MFC compared with MFCs using GGs (MFC reactor type R2) or GFB (MFC reactor type R3) individually. Compared with R3, the use of the combination biocathode (R1) can shorten the start-up time by 53.75%, improve coulombic efficiencies (CEs) by 21.0 ± 2.7% at external resistance (REX) of 500 Ω, and increase maximum power densities by 38.2 ± 12.6%. Though the start-up time and open circuit voltage (OCV) of the reactor R2 are similar to R1, the CE (REX = 500 Ω) and maximum power density of R2 are 21.4 ± 1.7% and 38.2 ± 15.6% lower than that of R1. Fluorescence in situ hybridization (FISH) analyses indicate the bacteria on cathodes of R1 and R2 are richer than that of R3. Molecular taxonomic analyses reveal that the biofilm formed on the biocathode surface is dominated by strains belonging to Nitrobacter, Achromobacter, Acinetobacter, and Bacteroidetes. Combination of GFB and GGs as biocathode material in MFC is more efficient and can achieve sustainable electricity recovery from organic substances, which substantially increases the viability and sustainability of MFCs.

Based on the single diamond grit scratching and normal grinding assisted with ELID (Electrolytic in Process Dressing), the surface/subsurface integrity of machined spectrosil 2000 and BK7 glasses under various material removal modes have been investigated. In Single diamond grit scratching tests, the scratching traces display four kinds of scratch characteristics according to different material removal modes. In the diamond normal grinding, the surface/subsurface integrity analysis shows BK7 glass has a better machinability than that of spectrosil 2000. Moreover, with the increasing ae(depth of cut), these two kinds of glasses had the opposite variation trends about the Ra values and the force ratio, which is attributed to various material removal modes. While contrasting these two kinds of optical glasses ground under the same aeparameters, the smaller grinding force and grinding force ratio (Fn/Ft), as well as the more stable force curves correspond to a better surface quality.

Through establishing the mathematical models of velocity and grinding force to optimize the installation angle with inclined axis grinding technology, the spherical surface of the ultra-hard alloy material was ground by formed electroplated diamond wheel. After analyzing the abrasion of grinding wheel, the results show that the inclined axis grinding technology of the formed grinding wheel can avoid the rotation dead spots of grinding wheel, and can make the grinding wheel surface contacted with work-piece fully which could make the worn more evenly. Finally, it obtains a surface in a high quality with the surface roughness of Ra is 12.88nm, and the form accuracy of PV is 124nm.

In situ sludge reduction of the oxic-settling-anaerobic (OSA) process was investigated in this study and microbial community diversity in the system was analyzed by using a PCR-denaturing gradient gel electrophoresis (DGGE) approach. Comparing to the conventional activated sludge method, the production of excessive sludge in the OSA process was shown to be efficiently reduced by 44-50 % and the organic loading rate was observed to have a slight impact on sludge yield. As demonstrated by the slight variation of Shannon diversity indices (SDI), the dominant microbial composition remained stable in the OSA sludge with the increase ofNs. About 63% of clones represented by predominant bands in the DGGE pattern were affiliated with the subclass ofb-proteobacteria. A number of bacteria in the OSA process were phylogenetically related to uncultured bacteria isolated from enhanced biological phosphorus removal (EBPR) sludge.

Experimental results indicate the previous theoretical model cannot predict well the surface roughness in single-point diamond turning on a precision lathe. In solving that, an improved model was presented in this paper. The difference between the previous model and the improved model is that the relative tool-workpiece vibration is measured before cutting operation using a capacitive displacement sensor in the previous model whilst the vibration is extracted from the measured surface profile in the improved model. The relative vibration was first studied under various cutting conditions to establish the vibration modes under corresponding cutting conditions. Then the surface roughness was predicted based on the vibration modes. The results prove that there is good agreement between the predicted values and measured values and the improved model is useful and reliable.

There has been increased interest in the use of SiC due to its excellent physical and mechanical properties. The diamond grinding process of SiC has been largely investigated in recent years, but the interface between diamond grain and SiC in grinding has not been completely understood. In this paper, a single diamond scratching method was presented in order to insight into the interface realizing on a SRV friction and abrasion test machine using three types of diamond grains with different shapes. The results analysis for material removal and diamond grain wear mechanisms in the interacting between the diamond grain and SiC can be useful to improve the grinding process of SiC.

In order to realize ductile machining of optical glasses using mono-layer nickel electroplated coarse-grained diamond grinding wheel, a novel conditioning technique features using a copper bonded diamond grinding wheels of 15m grain size dressed by ELID (electrolytic inprocess dressing) to condition the 46m grain sized diamond wheel has been developed. During the conditioning process, a force transducer was used to monitor the conditioning force, a coaxial optical distance measurement system was used to in-situ monitor the modified wheel surface status. White-light interferometry (WLI), scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to characterize the conditioned wheel surface status as well as the ground optical glass surface topography correspondingly. The experimental result indicates that a minimized wheel radial run-out error of less than 2μm as well as the top-flattened diamond grains of constant wheel peripheral envelop profile were generated on a 5-axis ultra-precision machine tool. The grinding experiment proved that the well conditioned 46μm coarse-grained diamond wheel can be used in realizing the ductile grinding of optical glass BK7, which indicates that the newly developed conditioning technique is feasible and applicable to introduce the coarse-grained diamond wheels into precision machining of brittle and hard-to-machine materials.

An advanced conditioning technique was developed to precisely and effectively condition the nickel electroplated mono-layer coarse-grained diamond grinding wheel of 46m and 91m grain size with an aim to fabricate Diamond Micro Tool Arrays (DMTA), to meet the high demands of form accuracy, surface quality and low subsurface damage in ductile machining of silicon carbide (SiC). The precision machining experiments on SiC were carried out on a precision grinder to determine the applicability of these fabricated diamond micro tool array (DMTA). The experimental result indicates that the newly developed DMTA is applicable and feasible to realize ductile machining on SiC with high efficiency and low diamond tool wear rate, which shows a good prospect to apply this new concept diamond tool type in precision machining of SiC, as well as the other brittle and hard-to-machine materials.

This paper aims to evaluate the surface and sub-surface integrity of optical glasses which were correspondingly machined by coarse and fine-grained diamond grinding wheels on Tetraform ‘C’ and Nanotech 500FG. The experimental results show that coarse-grained diamond grinding wheels are capable of ductile grinding of optical glasses with high surface and sub-surface integrity. The surface roughness values are all in nanometer scale and the sub-surface damages are around several micros in depth, which is comparative to those machined by fine-grained diamond wheels.

A simple and reliable welding method was developed to fabricate carbon nanotube probe used in atomic force microscopy here. First, apply less than 20 V voltage between silicon probe and carbon nanotube when they were in close proximity under direct view of optical microscope. Then, let carbon nanotube contact with silicon probe and increase the external voltage to 30–60 V until carbon nanotube was divided and attached to the end of silicon probe. The fabricated carbon nanotube probe could be shortened to appropriate length by electron bombard. The weld strength of carbon nanotube probe was calculated by drawing the ordinary AFM probe and measuring the probe's deflections. For one carbon nanotube probe with 75 nm diameter, the weld strength was calculated more than 268 nN. Carbon nanotube probe showed higher aspect ratio and could more accurately reflect the true topography of sample than silicon probe.

In this paper, a novel conditioning technique features using copper bonded diamond grinding wheels of 91μm grain size assisted with ELID (electrolytic in-process dressing) as a conditioner to precisely and effectively condition nickel electroplated monolayer coarse-grained diamond grinding wheels of 151μm grain size was firstly developed. Under optimised conditioning parameters, the super abrasive diamond wheel was well conditioned in terms of a minimized run-out error and flattened diamond grain surfaces of constant peripheral envelope, with the conditioning force monitored by a force transducer as well as the modified wheel surface status in-situ monitored by a coaxial optical distance measurement system. Finally the grinding experiment on BK7 was conducted using the well conditioned wheel with the corresponding surface morphology and subsurface damage measured by AFM (atomic force microscope) and SEM (scanning electron microscope) respectively. The experimental result shows that the newly developed conditioning technique is applicable and feasible to ductile grinding optical glass featuring nano scale surface roughness, indicating a prospect of introducing super abrasive diamond wheels into ductile machining of brittle materials.

A novel conditioning technique to precisely and effectively condition the nickel electroplated mono-layer coarse-grained diamond grinding wheel of 91m grain size was developed to fabricate a Diamond Micro Tool Array (DMTA) in ductile machining of brittle materials. During the fabricating process, a copper bonded diamond grinding wheels (91m grain size) dressed by ELID (electrolytic in-process dressing) was applied as a conditioner, a force transducer was used to monitor the conditioning force, and a coaxial optical distance measurement system was used to insitu monitor the modified wheel surface status. The experimental result indicates that the newly developed conditioning technique is applicable and feasible to generate required wheel topography of less than 2μm run-out error and grain geometries. The taper cutting test on BK7 proves the fabricated DMTA is capable of realizing ductile machining of brittle materials.

This paper presents a novel, rapid and damage-free method to polish the ultra-smooth surface of the SiC optics. First, the basic philosophy of this method is introduced, which uses the active radicals got from CF4 in the atmospheric pressure plasma zone to react with the SiC material at the optics surface to generate the vaporization of SiF4. Then, the design of the atmospheric pressure plasma jet and the corresponding prototyping polishing facility are introduced. The theoretical analysis on the necessary conditions to generate the excited radicals is also presented in this part. To verify the effectiveness of this novel polishing method, experiments on the generation of atmospheric pressure plasma and the SiC optics polishing are carried out with our prototyping facility. The experiment results show that plasma discharge is stable at the atmospheric pressure and sub-nanometer roughness of the polished SiC surface can be obtained.

With the development of science and technology, Atomic Force Microscope is widely applied to the field of machining process in nanometer scale. Due to the limitation of the inventive purpose of AFM, only height mode and deflection mode can be applied in AFM-tip micromachining. It can’t control the machining depth during the micromachining process at present. In this paper, a new micromachining system is set up, which composed of a high precision three-dimensional stage, an AFM, a diamond probe and a special control device. By utilizing variation parameters PID algorithm and controlling the machining depth directly, the micromachining system can resolve the problem mentioned above.

An improved arc welding method was developed to fabricate carbon nanotube probe under direct view of optical microscope. The new fabrication method here needs not coat silicon probe in advance with metal film, which greatly reduces the fabrication’s difficulty. An easy method for shortening the nanotube probe was also developed. The improved fabrication method here is simple and reliable. The fabricated carbon nanotube probe showed good properties of higher length-to-diameter aspect ratio, better wear characteristics than silicon probe.

The effects of free amplitude and amplitude setpoint on phase contrast images of poly (styrene–ethylene/butylenes–styrene) (SEBS) triblock copolymer have been studied by carbon nanotubes probe (CNTs probe). Phase angle contrast arises from different energy dissipation that occurs as a result of tip–sample adhesion and sample's viscoelasticity. With increasing free amplitude, phase angle contrast is a stronger function of the sample's viscoelasticity. However, the effect of tip–sample adhesion on phase angle contrast will increase with decreasing free amplitude or amplitude setpoint. The amplitude versus tip–sample distance curve shows both a local maximum and a local minimum that are caused by attractive and repulsive tip–sample interactions at low free amplitude. When amplitude setpoint is in the range between the local maximum and the local minimum value, the phase contrast image would likely produce severe instabilities. In addition, an interesting difference is found in the force plot curve on SEBS sample by using CNTs probe and ordinary silicon probe.

When grinding a large depth—diameter ratio aspheric part of high precision and high quality, the factors influencing surface roughness and profile accuracy of machined surfaces were theoretically analysed first. Afterwards the authors designed and manufactured the ultra-precision aspheric grinding system. The workpiece spindle, transverse guideway, longitudinal guideway and the grinder spindle are in aerostatic form. Turning accuracy of the workpiece spindle is 0.05 μm, the maximum rotational speed of the grinder is 80 000 r/min and the turning accuracy is 0.1 μm, and the resolution of linear displacement of the transverse and longitudinal guideway is 4.9 nm. The accuracy of the precise adjusting mechanism is 0.1 μm. The discharge principle of the dressing mechanism was developed in order to dress the diamond wheel. The ball-headed wheel has high profile accuracy after dressing. This mechanism solved the problem of on-position dressing of the case iron bonded diamond wheels and reduced the machining errors for aspheric surface components. Finally, grinding experiments for machining aspheric components were carried out. The grinding results indicated that the achieved profile accuracy is 0.3 μm and the surface roughness is less than 0.01 μm.

Long-term performance is of primary concern when considering the commercialized use of an microbial fuel cell(MFC). The long-term stability of MFC was studied using dairy manure as substrate over a testing time of 171 d. The results showed that the MFC could efficiently recover electricity from dairy manure during the long-time run, and the average power density was 6. 77 Wm-3 +/- 2. 11 W m-3. On day 70, the polarization curve was measured, the open circuit voltage, internal resistance and maximum power density of MFC were 0. 874 V, 22. 1 omega and 14. 1 W.m -3, respectively. The 30-day TCOD removal decreased with increasing test time, and the CE during the 121-150 d period reached 17.5% +/-3.3%. Phylogenetic analyses revealed that the dominant microbial communities in anodic biofilm were Proteobacteria (45%) , Bacteroidetes (22%) , Firmicutes (17% ) and Actinobacteria (11% ). At genera level, the bacteria with electricity production and (or) cellulose degradation ability, such as Clostridium and Cellulomonas were the abundant taxa.

To differentiate the transformation of dissolved organic matter (DOM) during corrosion cell-Fenton (CCF) post-treatment, the leachate was separated into five fractions by XAD-8 and XAD-4 resins (hydrophilic fraction, HPI; hydrophobic acid, HPO-A; transphilic acid, TPI-A; hydrophobic neutral, HPO-N; transphilic neutral, TPI-N). UV-Vis spectroscopy and fluorescence spectroscopy were used for the degradation analysis. Experimental results showed that DOM in landfill leachate reduced 61.8% of dissolved organic carbon (DOC). Especially for HPO-A and HPO-N, with the removal ratios were up to 74.9% and 66.5%, respectively. The predominant portion in the effluent was HPI (comprising 60.1% of DOC). Spectral analyses showed that the leachate DOM was composed of abundant condensed ring aromatic compounds and humic substances, with the HPO-A was the highest aromatic fraction. The ratio of absorbance at 253 nm and 203 nm (E253/E203) was decreased in the order of HPO-AHPO-NTPI-ATPI-NHPI. The unsaturated conjugated structures were efficiently destroyed after the CCF treatment, and the functional groups such as carbonyl, amine were also eliminated. The main fluorophores in leachate fractions were in the region of aromatic protein-like and visible fulvic-like. The fluorescence intensity of peaks in each fraction decreased after CCF treatment, especially for the fulvic-like fluorescent substances. The results indicated that the CCF treatment was efficient to remove the hydrophobic fractions and reduce the complicacy of leachate effluent.

The changes of skin tissue reflectance spectroscopy before and after being treated with the optical clearing agents of three different types of optical clearing within the wavelength rang of 400-1 000 nm, and the degree of changes in reflectance spectroscopy of each group skin during 0-60 min at 580 nm in vivo were real-time dynamically researched. The reflectance spectroscopy of skin tissue before and after being dealt by the optical clearing agents of glycerol, glucose and propylene glycol was measured using a USB-4000 fiber spectrophotometer at 0, 10, 20, 30, 40, 50 and 60 min. The results showed that the reflectance spectral intensity was distinctly decreased, but the reflectance was significantly increased gradually with the time prolonged. However, different optical clearing agents have different clearing progress. The relative decrease of reflectance of palm skin tissue before and after being dealt by the optical agents of 40% glycerol, 40% glucose and 40% propylene glycol during 10, 20, 30, 40, 50 and 60 min at the wavelength 580 nm is 5%, 7%, 9%, 10%, 11% and 12%, 9%, 13%, 16%, 19%, 21% and 22%, and 14%, 22%, 29%, 32%, 34% and 35%, respectively. The significant improvement in light transmittance and enhancement of light penetration through tissue was demonstrated for all solutions. The effect and processes of optical clearing of skin tissue is not only closely related to the choosing of the clearing agent type, but also related to the treatment time with the skin tissue. The clearing progress of different type optical clearing agent showed the order of 40% propylene glycol, 40% glucose and 40% glycerol.

There is an increasing focus on the secondary pollution of a municipal sewage treatment plant. To illuminate the environmental load of a sewage treatment process, a life cycle assessment (LCA) of a case project in Harbin was proposed by combining the process-based life cycle inventory (LCI) and the input-output based LCI in one framework. For classification of the effect factors and characterization, the calculation methods and models studied by Environmental Protection Agency (EPA) were applied and the improved analytic hierarchy process (AHP) was used to determine the indicator weights. Characterization results show that land filling space contributes to environmental load largely. Results of weighting assessment display the five bigger environmental impact categories. Results of LCA are intended to help inform and guide decisions about sewage treatment for existing wastewater treatment plants and those that are still in the planning phase in cities

An expanded granular sludge bed packed with porous sponge was started to treat wastewater contaminated by sulfide, nitrate, nitrite and organic carbon compounds. In inflow wastewater, potassium nitrate and sodium nitrite acted as electron acceptors, sodium sulfide acted as electron donor and glucose acted as organic carbon source. In the anoxic reactor, autotrophic denitrification happened together with heterotrophic denitrification whose percent was 21.76%. The destruction for anoxic environment had larger impact on nitrate removal than nitrite removal. The enhancement of influent loading rates had also effect on contaminants removal, but its effect was less than that from anoxic environment destruction. The ratio of sulfate to removal sulfide was about 40%, considering abiotic oxidation. The influent concentrations of sulfide, nitrate, nitrite and organic carbon were 200mgS/L，52.5mgN/L，20mgN/L，20mgC/L and corresponding conversion were 99%, 99%, 95.5% and 80% respectively, which actualized the simultaneous mixotrophic denitrification and desulfurization.

Much attention has been paid to femtosecond laser micro-scale machining for its unique advantages in recent years, given the possibilities for processing materials in the absence of thermal damage, and the minimum dimensions that can be machined. In this article a femtosecond laser micromachining workstation is described and a new micro-scale modification system is designed and established. The development of a workstation applying a femtosecond laser source to enable controllable micro-machining, which consists of light source, mechanical and optical components, three dimension (3D) work platform, and control system. Mechanical and optical components are designed for laser beam focusing. Computer software and control system resolves the graphics and to drive the 3D work platform, respectively. With the designed system, percussion, parallel and grid fabricating methods are used to machine different micro-scale structures on stainless steel surface. Besides, the material's removal mechanisms and machining parameters are also investigated.

To reduce the production cost of polyhydroxyalkanoates (PHAs), the process feasibility and physicochemical properties of PHAs synthesized by Alcaligenes latus, Staphylococcus epidermidis and activated sludge from malt waste, soy waste, confectionary waste, ice cream waste, milk waste, sesame oil and vinegar waste were analyzed. Results showed that through two-stage fed-batch fermentation, the maximum yield of PHAs accumulated by the three kinds of microorganisms from malt waste was 70.1%, 16.0% and 43.3%, separately. A. latus adapted itself to the food wastes in PHAs synthesis and new cell growth quickly. A. latus had higher PHAs yield and productivity under nitrogen limited condition. Micro-aerobically, S. epidermidis separated from sesame oil could produce polyhydroxybutyrate (PHB) with molecular weight of over 1 x 10(6). From soy waste, activated sludge accumulated polyhydroxybutyrate-co-hydroxyvaluate (PHBV) copolymer which had hydroxyvaleryl content (HV%) of 21%. Most food wastes are suitable for synthesizing PHAs with different physicochemical properties. The composition and properties of PHAs are influenced by the character of microorganism, the selection of substrates and optimization of ferment conditions.

A novel air purifier was designed for the removal of indoor formaldehyde. The air purifier was filled with glass beads (3 mm) coated with TiO2. The removal efficiency of this air purifier was examined in an airtight room. The results showed that 87.0%-93.8% of the formaldehyde was removed for the initial formaldehyde concentration of 0.727-1.815 mg/m3. The reaction rate equation of the air purifier was developed. The simulation of single device of the air purifier suggested the uniformity of the air flow in the device. Besides, a mathematical model to simulate the variation of formaldehyde in a room was constructed, in which there was continuous formaldehyde emission source and the air purifier was operated. The simulation result was also proved by the experimental data. The results revealed that using the air purifier at intervals could steadily keep the formaldehyde concentration below the National Air Quality Standard of China, i.e. 0.1 mg/m3.

By decreasing hydraulic retention times to increase substrates loading rates under anoxic conditions, an attached-growth bioreactor packed with porous sponges was started to treat the wastewater contaminated by sulfide, nitrate, nitrite and organic carbon. The influent concentrations of sulfide, nitrate-nitrogen, nitrite-nitrogen and TOC were 200 mg/L, 52.5 mg/L, 20 mg/L, 20 mg/L and relevant removal efficiencies were 99%, 99%, 95.5% and 80% respectively. The simultaneous removal of nitrogenous compounds, sulfide and organic carbon was achieved by the desulfurization and denitrification process. With increasing of the substrate loading rates, the adaptabilities of nitrate and nitrite to the influent shock load decreased. The adaptability of nitrate to the shock load was better than that of nitrite. Compared with the impact on the bioreactor brought by the increasing of the influent shock load, the destruction of anoxic environment had greater influence on the degradation of nitrate and nitrite. 60% of the removed sulfide was converted to sulfur by microorganisms. The dominant reaction of autotrophic denitrification occurred together with the heterotrophic denitrification whose percent was 21.76%.

The possible factors of sludge reduction such as sludge decay, energy uncoupled metabolism, anaerobic oxidation with low sludge production were discussed in an OSA (oxic-settling-anaerobic) process. It has been confirmed that sludge decay included hydrolysis and acidogenesis of dead microorganism and particle organic carbon adsorbed in sludge flocs and endogenous metabolism. The concentrations of SCOD, NH4(+)-N, TP in supernatant were increased gradually during sludge anaerobic treatment in the batch experiments. Soluble protein were increased up to 33.09 mg/L, exceeding carbohydrate change after 16 h anaerobic sludge treatment in the OSA batch experiment. It proved sludge lysis and hydrolysis in the OSA process. Endogenous SOUR in the OSA batch test was achieved 8 mg/(g h), more than 1.7 multiples as that in the CAS batch test. Higher endogenous metabolism promoted sludge reduction in the OSA process. Sludge decay is the decisive cause in OSA process, accounting for 66.7% of sludge production reduction. By batch experiments, it has been validated energetic uncoupling in OSA system since microorganisms were exposed in alternative anaerobic and aerobic environment. It accounts for about 7.5% of sludge production reduction. SCOD released from anaerobic sludge tank in the OSA process is used as the substrate for cryptic growth. The substrate is used for anoxic denitrifying, anaerobic phosphorus release, sulfate reduction and methane production. These anaerobic reactors have lower sludge production than aerobic oxidation when consumed SCOD is equivalent, which may lead to approximately 23.5% reduction of sludge production in the OSA system. It has been concluded that multiple causes result in minimization of excess sludge in OSA system.

The ecological security index (ESI) system including 27 indices for Heilongjiang Province was built up with the pressure-state-response (P-S-R) model. The weights of the indices were determined by analytical hierarchy process (AHP) and the ecological security status classification was evaluated by the ESI model for the years of 2000-2005. Then the development trend of ecological security from 2006 to 2010 was forecasted with the grey dynamic model. The results showed that the ecological security ranked the V grade in 2000 and the III grade in 2005, indicating the increase of ecological security. The forecasting results show that the ecological security will be the III grade for 2006, the II grade for 2007-2009, and the I grade for 2010 (ideal security). Thus it can be seen that the ecological security is ascending year by year, and the ecological environment quality is obviously improved with the implementation of eco-province construction since 2000. Through the effective facilitation of eco-province construction etc., the sustainable and healthy development of ecological security will be finally realized in Heilongjiang Province.

Dissolved organic matter in the secondary effluent from the W wastewater treatment plant (Harbin) was fractionated using XAD resins into five fractions: hydrophobic acid (HPO-A), hydrophobic neutral (HPO-N), transphilic acid (TPI-A), transphilic neutral (TPI-N) and hydrophilic fraction (HPI). The distribution, trihalomethane formation potential (THMFP), UV-Vis and FTIR spectra of organic fractions in the secondary effluent were examined. XAD fractionation results showed that HPO-A and HPI dominated in the secondary effluent, collectively accounting for about 70.8%. HPO-A was the main precursors for THMFP following chlorination. HPO-A had the highest specific THMFP (STHMFP) and averaged 232.9 microg/mg. The STHMFP of HPO-N, TPI-A, TPI-N and HPI ranged from 100 microg/mg to 125 microg/mg. Chlorination resulted in increased UV-Vis absorbance for TPI-N and decreased UV-Vis absorbance for HPO-A, HPO-N, TPI-A and HPI. After chlorination, O--H, C=C and aromatic ring were found to decrease while C--O was observed to increase for HPO-A, HPO-N, TPI-A and TPI-N. In addition,C=O and C--Cl were found to occur as by-products from the chlorination reaction.

Ecological security plays the same important role with political security, economic security and national security. Existing research is still primitive in their abilities to resolve ecological security problem. In this case study, the indicators for ecological security evaluation was established in a Pressure-State-Response (PSR) framework. Analytical Hierarchy Process (AHP) was applied to determine the weight of the indices. And the ecological security status classification was evaluated by the ESI model for the years of 1999-2005. Grey Model (1,1) was applied to forecast the development trend of ecological security from 2006 to 2010 in Heilongjiang Province. This paper validated a new case study based on an indicator-based PSR framework, and combined the AHP assessing approach and Grey Model (1,1) prediction model. The results showed that the ecological security ranked the grade Fifth in 2000 and the grade Third in 2005, indicating the increase of ecological security. Predictions show that ecological security will be the grade Third for 2006, the grade Second for 2007-2008, and the grade First for 2009-2010. Thus, it can be seen that the ecological security is improving year by year, and the ecological environment quality has obviously improved with the implementation of eco-province construction since 2000. Through the effective facilitation of eco-province construction etc., the sustainable and healthy development of ecological security will finally be realized in Heilongjiang Province.

Efficiency of pollution degradation, performance of activated sludge, effect of temperature fluctuation and recalcitrant organic compounds on system stability were investigated in OSA process for minimization of excess sludge. CAS process and OSA process were run with synthetic wastewater for 240 d. The results indicate that the OSA process excels the CAS process as a whole. COD removal efficiency in OSA process was slightly more than that in CAS. Removal efficiency of nitrogen and phosphorus could be enhanced to 42.58% and 53.84% respectively. Biological phosphorus accumulation in aerobic sludge from OSA and CAS were 2.69 g and 1.11 g per 100 g dry sludge, which further approved biological phosphorus removal in OSA process. Because of alternative aerobic and anaerobic environment in OSA process, sludge settleability and activity are improved. SVI in OSA process was 97 averagely. SOUR and dehydrogenase activity of sludge in OSA were higher appreciably than those in CAS. Protein concentration was higher above 1.69 mg x g(-1) and polysaccharide concentration was lower 6.7 mg x g(-1) in OSA sludge than those in CAS, which confirms the effect of anaerobic tank on sludge performance and microorganism diversity. Lower polysaccharide concentration in OSA sludge improves the settleability. Contrasting to CAS process, OSA process is more sensitive to impact of p-nitrophenol(PNP) and more inactive to temperature fluctuation. Temperature fluctuation led to an increase of the concentration of COD, NH4(+) -N, SS in effluent while sludge production Y(MLSS/COD) was reduced to 0.403 mg x mg(-1) and 0.227 mg x mg(-1) in CAS and OSA. When concentration of PNP was increased abruptly to 10 mg x L(-1), biological nutrient removal was ceased in OSA process. Once OSA system is impacted, it is difficult to restore.

Fly ash was investigated as a raw material for the preparation of a composite coagulant with sulfuric acid. Types of acid solution, H2SO4 concentration, ratio of H2SO4 to fly ash and stirring time were respectively examined as factors that influenced the efficiency of converting the iron and aluminum components into a composite coagulant and coagulation performance on domestic wastewater. The coagulant was attained at the condition of H2SO4-fly ash ratio of 5 mL/g, H2SO4 of 2 mol/L, stirring time of 4h and stabling time of 30 min, and contained Fe3+ of 0.010 8 mol/L with conversion efficiency of 11.4% and Al3+ of 0.035 4 mol/L with conversion efficiency of 4.3%. Removal efficiencies of COD and SS by this type of coagulant reached 70.4% and 91.9% respectively when treating domestic wastewater. This study provides a promising means to utilize fly ash for coagulation, which possibly makes wastewater treatment more economical and more sustainable.