载体保护下诱导碳酸钙对水泥砂浆微裂隙的修复作用

微生物诱导碳酸钙沉淀可有效填补和修复水泥浆凝结过程中难以避免的水化裂隙,提高水泥石力学强度和抗渗性能,从而可减少诱发的水泥微裂缝质量问题。文章以矿化性能良好的枯草芽孢杆菌为研究对象,通过菌种的活化与扩大培养、向水泥浆中不同方式的添加,测试和评价了不同工艺配方与养护条件下的水泥石力学和抗渗性能。结果表明:环境温度、pH值、钙源浓度分别是影响杆菌矿化能力的主要因素,水泥浆的碱性环境(pH值11~13)对杆菌的活性有明显的抑制作用,最大降低矿化能力达15.1%。多孔、吸附性好的页岩陶砂载体可有效降低碱性环境对杆菌活性的影响,相比于直接添加,载体附菌的添加方式可使水泥石抗压、抗折强度和抗渗压力分别提升11.5%、14.8%和33.3%。当菌液吸附率从0%增加到35%时,微生物水泥石的抗压、抗折强度和抗渗压力分别增加10.8%、47.0%以及25.0%。由此可知,研究的微生物微裂隙修复方法可有效提升水泥环力学和抗渗性能,结论可为固井水泥石质量提升和微生物水泥浆应用推广提供良好的指导和借鉴作用。

前列地尔脂微球载体对肾功能中度下降经皮冠状动脉介入治疗的肾脏保护作用

目的：通过观察肾功能中度下降行经皮冠状动脉介入治疗（PCI）患者术前术后肾功能各项指标,评估前列地尔脂微球载体对肾脏的保护作用.方法：选择肾功能中度下降且行PCI治疗的患者40例,随机分为实验组及对照组.实验组术前12h静脉给予前列地尔脂微球载体20μg,术后改为10μg Qd应用3d.对照组术前12h～术后24h持续静脉给予生理盐水1ml/kg/h.检测入组前、术后24h、48h、72h的Scr、CysC、eGFR.记录不良事件.结果：实验组与对照组患者术后24h、48h、72h的Scr、eGFR、CysC水平无显著性差异（P＞0.05）.实验组未出现不良事件,对照组出现心功能恶化5例;2组均无对比剂肾病发生.结论：前列地尔脂微球载体对肾功能中度下降PCI患者具有肾脏保护作用,与水化疗效相同,但较少发生心功能恶化这一不良事件.

链烷醇胺对水泥长期储存性能及粉体性能的影响

模拟水泥存放环境,研究了链烷醇胺类助磨剂对存放60d后水泥力学性能及粉体性能(如颗粒形貌和休止角)的影响。结果表明,水泥长期储存后抗压强度降低,而掺入链烷醇胺类助磨剂的水泥的强度降低幅度更大;长期储存后水泥颗粒表面出现了明显的凝胶状物质,休止角也明显增大。

链烷醇胺对水泥长期储存性能及粉体性能的影响

模拟水泥存放环境，研究了链烷醇胺类助磨剂对存放6Od后水泥力学性能及粉体性能（如颗粒形貌和休止角）的影响。结果表明，水泥长期储存后抗压强度降低，而掺入链烷醇胺类助磨剂的水泥的强度降低幅度更大；长期储存后水泥颗粒表面出现了明显的凝胶状物质，休止角也明显增大。

Enhanced photocatalytic properties of hierarchical nanostructured TiO_2 spheres synthesized with titanium powders

Using Ti powder as reagent, TiO 2 nanoneedle/nanoribbon spheres were prepared via hydrothermal method in NaOH solution. The samples were characterized by field emission scanning electron microscopy （FESEM）, transmission electron microscopy （TEM） with selected area electron diffraction （SAED）, X-ray diffraction （XRD）, and UV-visible light absorption spectrum. The results indicate that the growth orientations of the crystals are influenced by the hydrothermal temperature and NaOH concentration. The diameter of the nanoneedle spheres and nanoribbon spheres （40 50 μm） are almost the same as that of Ti powders. TiO 2 nanoneedle/nanoribbon sphere powders are anatase after heat treatment at 450 °C for 1 h. Furthermore, methyl orange was used as a target molecule to estimate the photocatalytic activity of the specimens. Under the same testing conditions, the photocatalytic activities of the products decrease in the following order： TiO 2 nanoneedle sphere, TiO 2 nanoribbon sphere and P25.

Effects of CO_2 Enrichment on Microstructure and Ultrastructure of Two Species of Freshwater Green Algae

order to investigate the morphological response of freshwater green algae to elevated CO2 concentration, Chlamydomonas reinhardtii Dang and Scenedesmus obliquus Kutz were cultured with enriched CO2, and their microstructure and ultrastructure were examined by microscopy and electron microscopy. The effect of CO2 enrichment to 186 mumol/L, was insignificant on the shape and size of C. reinhardtii, but significant in reducing the volume of S. obliquus. High-CO2 increased the amount of chloroplast. The pyrenoids occurred in low-CO2-grown cells but not in high-CO2-grown ones and more starch granules were observed in the former.

Bovine Serum Albumin (BSA) Microspheres Containing Methotrexate (MTX) I.Pharmaceutical Aspects

Microspheres Ⅰ,Ⅱ and Ⅲ were produced by emulsion technique.Microsphere I was solidified by glutaraldehyde crosslinking,microsphere Ⅱ was solidified by glutaraldehyde crosslinking and further treated with glycine solution and microsphere Illwas solidified by heating denaturation only.The results showed that the microsphere diameter produced by cross[inking was bigger than that prepared by heating.The microsphere Ⅱ had higher hydrophilicity than Microsphere I had.The methotrexate (MTX) contents in microspheres Ⅰ and Ⅱ were 2.73±0.053%,2.87±0.119% respectively. microsphere Ⅲ was only blank microspheres with MTX adsorbed on their surfaces.In vitro release studies,microspheres I and I have maintained sustained release of MTX till the next day,it was found that the drug releases from microspheres Ⅰ and Ⅱ were governed by Higuchi diffusion law.

Synthesis of Bi_2S_3 microsphere and its efficient photocatalytic activity under visible-light irradiation

A novel Bi2S3 microsphere was fabricated through one-pot urea-assisted solvothermal method.The synthesized Bi2S3 microsphere was characterized by X-ray diffraction(XRD),scanning electron microscopy(SEM),Fourier transformed infrared spectroscopy(FT-IR)and thermal gravimetric analysis and differential thermal analysis(DTA-TG).Subsequently,the photocatalytic performances of Bi2S3 microsphere were evaluated by photocatalytic degradation of methyl orange(MO)simulation solution under visible-light irradiation.The results show that,Bi2S3 microsphere could be used as a potential cost-efficient catalysis for eliminating of methyl orange from aqueous solutions,whose degradation rate could reach 91.07%within 180 min.Besides,a tentative photocatalytic reaction mechanism was discussed according to the energy band position.Therefore,this work indicated a simplistic approach for the fabrication of visible-light responsive Bi2S3 microsphere photocatalyst,which can be used as a valuable candidate in solar energy conversion and environment pollution treatment.

Optimization of cavitation venturi tube design for pico and nano bubbles generation

Hydrodynamic cavitaion venturi tube technique is used for pico and nano bubble generations in coal column flotation. In order to determine the optimal design of hydrodynamic cavitation venture tube for pico and nano bubble generation, a four-factor three-level Central Composite Design of Experimental was conducted for investigating four important design parameters of cavitation venturi tube governing the median size and the volume of pico and nano bubbles. The test results showed that maximum volume of pico and nano bubbles, 65–75%, and minimum mean pico and nano bubble size,150–240 nm, were achieved at the medium ratio of the diameter of outlet of the venturi-tube and diameter of throat(3–4), medium outlet angle(11–13°), high inlet angle(26–27°) and high ratio of the length of the throat and the diameter of throat(2.3–3). Study the effects of the producing pico and nano bubbles on fine coal flotation was performed in a 5 cm diameter 260 cm height flotation column. The optimal percentage of pico and nano bubbles was about 70%, which produced maximum combustible material recovery of 86% with clean coal ash content of 11.7%.

Characterization of microstructure evolution of cement paste by micro computed tomography

Micro computed tomography (Micro-CT) was applied to obtain three-dimensional images of the microstructure of cement paste (water-to-cement mass ratio of 0.5) at different ages. By using the Amira software, component phases of the cement paste such as pores, hydration products, and unhydrated clinker particles were segmented from each other based on their 3D image grey levels; their relative contents were also calculated with the software, and the data are 61.2%, 0% and 38.8% at the beginning of hydration and 11.8%, 78.5% and 9.7% at 28 d age, respectively. The hydration degree of cement paste at different ages was compared with the experimental data acquired by loss on ignition (LOI) tests. The results show that the calculated and measured data reasonably agree with each other, which indicates that micro-CT is a useful and reliable approach to characterize the micro structure evolution of hydrating cement paste.

Effects of temperatures and pH values on rheological properties of cemented paste backfill

In this study,different influence mechanisms associated with temperatures and pH values were investigated through cemented paste backfill(CPB)systems.CPB samples were prepared with temperatures ranging from 10 to 50℃ in 10℃ increments and pH values of 3,7,and 13.Then,the CPB mixture were subjected to rheological tests,thermogravimetric analysis(TG),derivative thermogravimetry analysis(DTG),Fourier-transform infrared spectroscopy(FT-IR),and scanning electron microscopy(SEM).Results demonstrated that the temperatures had significant effects on the rheological properties of CPB,whereas the effects of pH values were relatively unapparent.Higher temperatures(over 20℃)were prone to bring higher shear stress,yield stress,and apparent viscosity with the same pH value condition.However,an overly high temperature(50℃)cannot raise the apparent viscosity.Non-neutral conditions,for pH values of 3 and 13,could strengthen the shear stress and apparent viscosity at the same temperature.Two different yield stress curves could be discovered by uprising pH values,which also led to apparent viscosity of two various curves under the same temperatures(under 50℃).Microscopically,rheological properties of CPB were affected by temperatures and pH values which enhanced or reduced the cement hydration procedures,rates,products and space structures.

Characterization of a bioflocculant from a newly isolated Vagococcus sp. W31

Screening of microorganisms producing flocculating substances was carried out. A strain secreting a large amount of bioflocculant was isolated from wastewater samples collected from the Little Moon River in Beijing. Based on the morphological properties and 16S rDNA sequence analysis, the isolate (designated W31) was classified as Vagococcus sp. A bioflocculant (named MBFW31) produced by W31 was extracted from the culture broth by ethanol precipitation and purified by gel chroma-tography. MBFW31 was heat-stable and had strong flocculating activity in a wide range of pH with relatively low dosage re-quirement. MBFW31 was identified as a polysaccharide with molecular weight over 2×106. It contained neutral sugar and uronic acid as its major and minor components, respectively. Infrared spectra showed the presence of hydroxyl, carboxyl and methoxyl group in its molecules. The present results suggested that MBFW31 had potential application in wastewater treatment.

Hydration mechanism of low quality fly ash in cement-based materials

The hydration mechanism of low quality fly ash in cement-based materials was investigated. The hydration heat of the composite cementitious materials was determined by isothermal calorimetry, and the hydration products, quantity, pore structure and morphology were measured by X-ray diffraction(XRD), thermalgravity-differential thermal analysis(TG-DTA), mercury intrusion porosimetry(MIP) and scanning electron microscopy(SEM), respectively. The results indicate that grinding could not only improve the physical properties of the low quality fly ash on particle effect, but also improve hydration properties of the cementitious system from various aspects compared with raw low quality fly ash(RLFA). At the early stage of hydration, the low quanlity fly ash acts as almost inert material; but then at the later stage, high chemical activity, especially for ground low quality fly ash(GLFA), could be observed. It can accelerate the formation of hydration products containing more chemical bonded water, resulting in higher degree of cement hydration, thus denser microstructure and more reasonable pore size distribution, but the hydration heat in total is reduced. It can also delay the induction period, but the accelerating period is shortened and there is little influence on the second exothermic peak.

Treatment of chitin-producing wastewater by micro-electrolysis-contact oxidization

The technique of micro-electrolysis-contact oxidization was exploited to treat chitin-producing wastewater. Results showed that Fe-C micro-electrolysis can remove about 30% CODcr, raise pH from 0.7 to 5.5. The CODcr removal efficiency by biochemical process can be more than 80%. During a half year抯 operation, the whole system worked very stably and had good results, as proved by the fact that every quality indicator of effluent met the expected discharge stan-dards; which means that chitin wastewater can be treated by the technique of micro-electrolysis, contact oxidization.

Microstructure and photocatalytic activity of Ni-doped ZnS nanorods prepared by hydrothermal method

Pure ZnS and Ni^2+-doped ZnS nanorods (Zn1-xNixS, x=0, 0.01, 0.03, 0.05 and 0.07, mole fraction,%) were synthesized by hydrothermal method. The effects of Ni2+ doping on the phase-structure, morphology, elemental composition and optical properties of the samples were investigated by X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray energy dispersive spectrometry (EDS) and ultraviolet–visible spectroscopy (UV-Vis), respectively. The photocatalytic activity of Zn1-xNixS nanorods was evaluated by the photodegradation of organic dyes Rhodamine B (RhB) in aqueous solution under UV light irradiation. The results show that all samples exhibit wurtzite structure with good crystallization. The morphologies are one-dimensional nanorods with good dispersion, and the distortion of the lattice constant occurs. The band gap of Zn1-xNixS samples is smaller than that of pure ZnS, thus red shift occurs. Ni^2+-doped ZnS nanocrystals can enhance photocatalytic activities for the photodegradation of RhB. Especially, Zn0.97Ni0.03S sample exhibits better photocatalytic performance and photocatalytic stability for the decomposition of RhB.

Estimation of Transported Pollutant Load from Small Urban Kahuwa River Micro-catchment in Lake Kivu, Democratic Republic of Congo

This study estimated pollutant load from Kahuwa micro-catchment into Lake Kivu. The micro-catchment was sampled monthly for a year at six locations to capture the contribution of agricultural land, industries and commercial blocks. Both wet and dry depositions in terms of TN （total nitrogen） and TP （total phosphorus） were estimated monthly. The level of pollution was estimated using LISEC index and IPO （organic pollution indices）. Results show that Kahuwa River micro-catchment is polluted mainly by waste dumping sites and industries within the micro-catchment. The general load to the outlet was respectively about 0.35 tons per year （t/yr） for BODs, 1.9 t/yr for COD, 32.73 t/yr for TP and 224.37 t/yr for TN. Atmospheric deposition of nutrient contributed for about 4% and 18% of TP, 3% and 0.01% of TN during dry and wet deposition, respectively.

Preparation and corrosion resistance of superhydrophobic coatings on AZ31 magnesium alloy

In order to improve the corrosion resistance of the Mg alloys, the superhydrophobic coatings on AZ31 Mg alloy wereprepared by a two-step process of micro-arc oxidation treatment and superhydrophobic treatment in stearic acid ethanol solution. Theeffects of voltages, frequencies and treatment time on the contact angle of the superhydrophobic treated sample were investigated.The results showed that with increasing the voltage, frequency and treatment time, all of the contact angles of the superhydrophobictreated sample increased first, and then decreased, reaching the maximum values at 350 V, 1000 Hz and 5 min, respectively. Theoptimal superhydrophobic coating was mainly composed of MgO and Mg2SiO4 phases, with the pore diameter of ～900 nm, thethickness of ～6.86 μm and the contact angle of 156.96°. The corrosion current density of the superhydrophobic AZ31 sampledecreased by three orders of magnitude, and the amount of hydrogen evolution decreased by 94.77% compared with that of the AZ31substrate sample.

Experimental study on micro-electrolysis technology for pharmaceutical wastewater treatment

Experiments were conducted to study the role of micro-electrolysis in removing chromaticity and COD and improving the biodegradability of pharmaceutical wastewater. The results showed that the use of micro-electrolysis technology could remove more than 90% of chromaticity and more than 50% of COD and greatly improved the biodegradability of pharmaceutical wastewater. Lower initial pH could be advantageous to the removal of chromaticity. A retention time of 30 minutes was recommended for the process design of micro-electrolysis.

Heavy metal contamination, physico-chemical and microbial evaluation of water samples collected from chromite mine environment of Sukinda, India

Water samples from chromite mine quarry of Sukinda and its adjacent areas were analyzed for their heavy metal contamination along with physico-chemical and microbial contents. The chromite mine water samples possessed high concentrations of heavy metals in the order of Cr〉Fe〉Zn〉Ni〉Co〉Mn while ground water did not show any heavy metal contamination except Fe. Physico-chemical parameters of mine water samples showed deviation from those of normal water. Mine water harboured low microbial populations of bacteria, fungi and actinomycetes in comparison with mine adjacent water samples. The correlation of data between metals with physico-chemical parameters showed both positive and negative responses while that of metal and microbial population exhibited negative correlation. Bacterial strains isolated from chromite mine water exhibited high tolerance towards chromium and other heavy metals as well as antibiotics which could be used as an indicator of heavy metal pollution.

Electrocatalytic generation of reactive species and implications in microbial inactivation

Controlling microbial proliferation in water systems,including wastewater,recreational water,and drinking water,is essential to societal health.Microbial inactivation through electrochemically generated reactive species(RS)mediated pathways provides an effective route toward this microbial control.Herein we provide an overview of recent progress toward electrocatalytic generation of RS and their application in water disinfection,with a focus on the selective production of RS,the microorganism interactions with RS(including both RS mechanisms of action and innate microorganism responses to RS),and practical implementation of electrochemically generated RS for microbial inactivation.The article is concluded with a perspective where the challenges and opportunities of RS‐based electrochemical disinfection of water are highlighted,along with possible future research directions.