The Promotion Effect of Low-Molecular Hydroxyl Compounds on the Nano-Photoelectrocatalytic Degradation of Fulvic Acid and Mechanism

A significant promotion effect of low-molecular hydroxyl compounds(LMHCs) was found in the nano-photoelectrocatalytic(NPEC) degradation of fulvic acid(FA),which is a typical kind of humic acid existing widely in natural water bodies,and its influence mechanism was proposed.A TiO_2 nanotube arrays(TNAs) material is served as the photoanode.Methanol,ethanediol,and glycerol were chosen as the representative of LMHCs in this study.The adsorption performance of organics on the surface of TNAs was investigated by using the instantaneous photocurrent value.The adsorption constants of FA,methanol,ethanediol,and glycerol were 43.44,19.32,7.00,and 1.30,respectively,which indicates that FA has the strongest adsorption property.The degradation performance of these organics and their mixture were observed in a thin-layer reactor.It shows that FA could hardly achieve exhausted mineralization alone,while LMHCs could be easily oxidized completely in the same condition.The degradation degree of FA,which is added LMHCs,improves significantly and the best promotion effect is achieved by glycerol.The promotion effect of LMHCs in the degradation of FA could be contributed to the formation of a tremendous amount of hydroxyl radicals in the NPEC process.The hydroxyl radicals could facilitate the complete degradation of both FA and its intermediate products.Among the chosen LMHCs,glycerol molecule which has three hydroxyls could generate the most hydroxyl radicals and contribute the best effective promotion.This work provides a new way to promote the NPEC degradation of FA and a direction to remove humus from polluted water.

Toxic Effects of Nano-CuO, Micro-CuO and Cu²⁺on <i>Chlorella</i>sp.

The 96 h acute toxic effects of nano-CuO (N-CuO), micro-CuO (M-CuO) and 2+ on Chlorella sp. were investigated in this paper. The results showed that toxicities decreased in an order of Cu2+>N-CuO>M-CuO. The 96 h EC50 of Cu2+ on Chlorella sp. was 1.06 mg /L, and of N-CuO it was 74.61 mg /L, while no pronounced toxicity was observed when the concentration of M-CuO was lower than 160 mg/L. Further experiments were carried out in order to study the toxicity mechanism of nano-CuO on Chlorella sp.. The results of Cu2+ release from N-CuO showed less than 0.2 mg/L Cu2+ were released, so the release of Cu2+ was not responsible for the toxicity. Further experiments showed N-CuO inhibited formation of Chlorophyll A. Content of Chlorophyll A in the control group was 4.75 mg/108 cells, while it declined to 2.89 mg/108 cells for 160 mg/L N-CuO after 96 h, which indicated that N-CuO could inhibit photosynthesis of Chlorella sp.. Moreover, N-CuO condensed with algal cells. It affected the activity of SOD and POD, indicating that N-CuO could cause oxidant stress to Chlorella sp.. These may be the toxicity mechanism.

Effects of Nano-TiO2 on Chlamydomonas reinhardtii Cell Surface under UV,Natural Light Conditions

Cell surface of aquatic organisms constitutes a primary site for the interaction and a barrier for the nano-TiO2 biological effects.In the present study,the biological effects of nano-TiO2 on a unicellular green algae Chlamydomonas reinhardtii were studied by observing the changes of the cell surface morphology and functional groups under UV or natural light.By SEM,the cell surface morphology of C.reinhardtii was changed under UV light,nano-TiO2 with UV light or natural light,which indicated that photocatalysis damaged cell surface.It was also observed that cell surface was surrounded by TiO2 nanoparticles.The ATR-FTIR spectra showed that the peaks of functional groups such as C-N,-C=O,-C-O-C and P=O,which were the important components of cell wall and membrane,were all depressed by the photocatalysis of nano-TiO2 under UV light or natural light.The photocatalysis of nano-TiO2 promoted peroxidation of functional groups on the surface of C.reinhardtii cells,which led to the damages of cell wall and membrane.

The Inhibition Effect of Tert-Butyl Alcohol on the TiO_2 Nano Assays Photoelectrocatalytic Degradation of Different Organics and Its Mechanism

The inhibition effect of tert-butyl alcohol(TBA), identified as the·OH radical inhibitor, on the TiO_2 nano assays(TNA) photoelectrocatalytic oxidation of different organics such as glucose and phthalate was reported. The adsorption performance of these organics on the TNA photoelectrode was investigated by using the instantaneous photocurrent value, and the degradation property was examined by using the exhausted reaction. The results showed that glucose exhibited the poor adsorption and easy degradation performance, phthalate showed the strong adsorption and harddegradation, but TBA showed the weak adsorption and was the most difficult to be degraded. The degradation of both glucose and phthalate could be inhibited evidently by TBA. But the effect on glucose was more obvious. The different inhibition effects of TBA on different organics could be attributed to the differences in the adsorption and the degradation property. For instance, phthalate of the strong adsorption property could avoid from the capture of·OH radicals by TBA in TNA photoelectrocatalytic process.

Shielding effect of a nano-circular inclusion acting on semi-infinite wedge cracks

The model of a screw dislocation near a semi-infinite wedge crack tip inside a nano-circular inclusion is proposed to investigate the shielding effect of nano inclusions acting on cracks. Utilizing the complex function method, the closed-form solutions of the stress fields in the matrix and the inclusion region are derived. The stress intensity factor, the image force, as well as the critical loads for dislocation emission are discussed in detail. The results show that the nano inclusion not only enhances the shielding effect exerted by the dislocation, but also provides a shielding effect itself. Moreover, dislocations may be trapped in the nano inclusion even if the matrix is softer than the inclusion. This helps the dislocation shield crack, and reduces the dislocation density within the matrix.

The Effect and Mechanism of Nano-Cu Lubricating Additives on the Electroless Deposited Ni-W-P Coating

The coating and deposition process with excellent anti wear and suitable for industrial application were developed, and the optimum bath composition and process were obtained by studying the influence of the bath composition, temperature and pH value on the deposition rate and the plating solution stability. Moreover, the tribological properties of nano-Cu lubricating additives and electroless deposited Ni-W-P coating as well as their synergistic effect are researched using ring-block abrasion testing machine and energy dispersive spectrometer. Research results show that Ni-W-P alloy coating and nano-Cu lubricating additive have excellent synergistic effect, e g, the wear resistance of Ni-W-P alloy coating （with heat treatment and the oil with nano-Cu additives） has increased hundreds times than 45 steel as the metal substrate with the basic oil, and zero wear is achieved, which breaks through the bottleneck of previous separate research of the above-mentioned two aspects.

Study on Extended Gate Field Effect Transistor with Nano-TiO-2 Sensing Membrane by Sol-Gel Method

The nano-titanium dioxide (nano-TiO_2) sensing membrane,fabricated by sol-gel technology,was used as the pH-sensing layer of the extended gate field effect transistor (EGFET) device.The objective of this research is the preparation of titanium dioxide materials by sol-gel method using Ti(OBu)_4 as the precursor.In this study,we fabricated a nano-titanium dioxide sensing layer on the ITO glass by dip coating.In order to examine the sensitivity of the nano-TiO_2 films applied to the EGFET devices,we adopted the ITO glass as substrate,and measured theⅠ_(DS)-Ⅴ_G curves of the nano-titanium dioxide separative structure EGFET device in the pH buffer solutions that have different pH values by the Keithley 236 Instrument.By the experimental results,we can obtain the pH sensitivities of the EGFET with nano-TiO_2 sensing membrane prepared by sol-gel method,which is 59.86mV/pH from pH 1 to pH 9.

Synergistic Effect between Nano-ceramic Lubricating Additives and Electroless Deposited Ni-W-P Coating

The major solving ways for the material wear are surface modification and lubrication. Currently, the researches at home and abroad are all limited to the single study of either nano-lubricating oil additive or electroless deposited coating. The surface coating has high hardness and high wear resistance, however, the friction reduction performance of the coating with high hardness is not good, the thickness of the coating is limited, and the coating can not regenerate after wearing. The nano-lubricating additives have good tribological performance and self-repair function, but under heavy load, the self-repair rate to the worn surface with the nano-additives is smaller than the wearing rate of the friction pair. To solve the above problems, the Ni-W-P alloy coating and deposition process with excellent anti-wear, and suitable for industrial application were developed, the optimum bath composition and process can be obtained by studying the influence of the bath composition, temperature and PH value to the deposition rate and the plating solution stability. The tribological properties as well as anti-wear and friction reduction mechanism of wear self-repair nano-ceramic lubricating additives are also studied. The ring-block abrasion testing machine and energy dispersive spectrometer are used to explore the internal relation between the coating and the nano-lubricating oil additives, and the tribology mechanism, to seek the synergetic effect between the two. The test results show that the wear resistance of Ni-W-P alloy coating （with heat treatment and in oil with nano-ceramic additives） has increased hundreds times than 45 steel as the metal substrate in basic oil, the friction reduction performance is improved. This research breaks through the bottleneck of previous separate research of the above-mentioned two methods, and explores the combination use of the two methods in industrial field.

Evaluation and Exploration of Se-enriching Effects of Microbial Nano-selenium on Several Kinds of Vegetable

[Objectives] This study was carried out to explore the selenium-enriching effect of different crops, and provide certain references for production of selenium-enriched agricultural products. [Methods] Four kinds of crops （tomato, leaf mustard, peanut, and carrot） were exogenous selenium fertilizer treated, to explore the selenium-enriching effects on these crops. [Results] Exogenous application of microbial nano-selenium can significantly increase the selenium content of the crops, of which the effects on big tomato （Weiyanuo） were the best. After spraying, the selenium content increased by 1.39 times, and at the same time the sugar content of tomato was also increased. [Conclusions] This study is expected to provide references for increase of the selenium content of agricultural products.

Nano Lanthanum Oxide Preparation by Alkalescent Ammonium Citrate System and Its Primary Biological Effect

Using alkalescent ammonium(AAC)as precipitatnt, the diameter of nano La_2O_3 powder with diameter in 80 nm and less was prepared by the method of homogeneous precipitation, and reactant concentration, temperature and pH were studied and confirmed. The best precipitated concentration is from 0.2 to 0.5 mol·L^(-1), and the diameter of compounded powder turns small as the temperature gradually becomes high, and the pH from 6 to 8 is the best and the concentration of precipitant does not affect the diameter of compounded powder significantly. Meanwhile, most experiments lasting for fifty days in the greenhouse, and the results are 0.2 g·kg^(-1) nano La_2O_3 powder is enorgh for increasing biomass by 133% compared with that of the CK.

高选择性部分氧化催化剂Au-Pd/TiO_(2)-SiO_(2)的设计合成与苯甲醇部分氧化反应

贵金属纳米催化剂在苯甲醇部分氧化制备苯甲醛过程中具有较高的反应活性,产物苯甲醛选择性较低。采用一锅法制备TiO_(2)改性的Au-Pd/TiO_(2)-SiO_(2)纳米合金催化剂并用于苯甲醇部分氧化反应。对催化剂结构表征关联反应进行评价。结果表明:少量TiO_(2)的引入会改善贵金属纳米颗粒在载体表面的分散度,调变了金钯合金表面的电子结构,提高反应活性,并显著提高载体表面Lewis酸位的数量,从而大幅提高苯甲醛选择性;大量TiO_(2)的引入会导致金钯合金程度降低,产生大量的Bronsted酸位,使得反应活性和产物选择性都大幅降低。

Surface effects of adsorption-induced resonance analysis on micro/nanobeams via nonlocal elasticity

The governing differential equation of micro/nanbeams with atom/molecule adsorption is derived in the presence of surface effects using the nonlocal elasticity. The effects of the nonlocal parameter, the adsorption density, and the surface parameter on the resonant frequency of the micro/nanobeams are investigated. It is found that, in ad- dition to the nonlocal parameter and the surface parameter, the bending rigidity and the adsorption-induced mass exhibit different behaviors with the increase in the adsorption density depending on the adatom category and the substrate material.

磁电弹性材料含正六边形纳米缺陷的表面效应研究

在磁电弹性材料断裂力学框架下,利用表面弹性理论和解析函数边值理论,解析研究了反平面机械载荷、面内电载荷和磁载荷耦合作用下磁电弹性体中正六边形孔边均布六条等长裂纹的Ⅲ型断裂力学问题,确定了考虑表面效应时纳米尺寸裂纹问题的精确解.基于以上解析解,通过数值算例揭示了表面效应、缺陷几何参数及所施加的损坏载荷分别在两种理想裂纹面电磁条件假设下对断裂参数的影响规律.研究发现:考虑表面效应时影响裂纹扩展的因素与经典弹性理论解答明显不同.各个物理分量呈现出显著的尺寸依赖效应,但随着缺陷尺寸的增加,表面效应的影响呈下降趋势,并趋于经典弹性理论值.研究可为该材料应用于微纳米结构和微机电系统提供理论指导.

The Casimir Topological Effect and a Proposal for a Casimir-Dark Energy Nano Reactor

A basically topological interpretation of the Casimir effect is given as a natural intrinsic property of the geometrical topological structure of the quantum-Cantorian micro spacetime. This new interpretation compliments the earlier conventional interpretation as vacuum fluctuation or as a Schwinger source and links the Casimir energy to the so called missing dark energy density of the cosmos. We start with a general outline of the theoretical principle and basic design concepts of a proposed Casimir dark energy nano reactor. In a nutshell the theory and consequently the actual design depends crucially upon the equivalence between the dark energy density of the cosmos and the faint local Casimir effect produced by two sides boundary condition quantum waves. This Casimir effect is then colossally amplified as a one sided quantum wave pushing from the inside on the one sided M?bius-like boundary with nothing balancing it from the non-existent outside. In view of the present theory, this one sided M?bius-like boundary of the holographic boundary of the universe is essentially what leads to the observed accelerated expansion of the cosmos. Thus in principle we will restructure the local topology of space using material nanoscience technology to create an artificial local high dimensionality with a Dvoretzky theorem like volume measure concentration. Needless to say the entire design is based completely on the theory of quantum wave dark energy proposed by the present author. The quintessence of the present theory is easily explained as the intrinsic Casimir topological energy where produced from the zero set of the quantum particle when we extract the empty set quantum wave from it and find by restructuring space via plates similar to that of the classical Casimir experiments but with some modification.

纳米偏高岭土复配PVA对水泥早强性能的影响研究

为了改善矿用水泥基封孔材料早期强度低的缺陷,在水泥的原有基础上添加纳米偏高岭土复配PVA(聚乙烯醇)作为早强剂改善水泥早期强度。通过抗压强度、流动度、凝结时间的测试以及XRD、SEM等微观结构分析得出,当纳米偏高岭土质量比为5%,PVA质量比为0.2%时,对水泥早期强度的提高最明显,其相较于同龄期空白组1、3、7 d的抗压强度分别提升了77.1%、40.03%、27.15%。PVA作为分散剂加入,使得纳米偏高岭土复配PVA的实验组水泥水化速率加快,水化产物增多,内部结构更加紧密,抗压性能更好。

生物炭改性及其对除草剂污染水体和土壤修复的研究进展

除草剂已被大量使用于现代农业生产,而长期使用除草剂可能造成其在土壤中大量残留,或通过降水、淋溶和径流污染水体,因此引发环境污染问题和食品安全问题。生物炭作为一种绿色、高效的吸附剂已被广泛用于修复有机物污染水体和土壤。本文介绍了酸碱、有机物和金属盐浸渍改性,纳米零价铁和微生物负载改性等生物炭改性方法;综述了改性生物炭在除草剂污染修复中的应用情况,对比分析了生物炭改性前后的修复效果;探讨了改性生物炭自身特性、环境条件对改性生物炭修复除草剂污染的影响及机制。未来仍需对改性生物炭在除草剂污染修复过程中的稳定性、长效性和安全性等方面开展研究。

考虑纳米限域效应的页岩油二氧化碳吞吐适应性

页岩储层通常物性差,孔喉细小,采用常规的注水、注化学剂等措施往往无法取得较好的开发效果。CO_(2)吞吐不仅能有效降低油气界面张力、降低原油黏度等,达到提高页岩油采收率的目的,而且注入地层中的部分CO_(2)还能实现永久封藏,有助于实现碳达峰、碳中和。采用数值模拟方法研究页岩油CO_(2)吞吐的适应性。页岩储层以微纳米级孔喉系统为主,在流体流动过程中会产生较大的毛管压力,影响原油组分的热力学相行为,进而影响组分的计算和多孔介质中的流体流动,因此在流体模型中引入纳米限域效应,通过临界压力和临界温度变化来模拟纳米限域效应对流体组分相行为的影响。同时为探究页岩油CO_(2)吞吐在压裂改造增产区不同缝网渗透率与基质渗透率比值(K_(f)/K_(m))和含油饱和度(S_(o))下的适应性,以采出程度增量和换油率为参考指标,得到不同K_(f)/K_(m)和S_(o)下的适应性图版。结果表明,与不考虑纳米限域效应相比,考虑纳米限域效应的组分p-T相图整体向上偏移,泡点压力升高。当K_(f)/K_(m)为1000、CO_(2)吞吐采出程度增量达到1.5%时,S_(o)适应性界限为0.54;而K_(f)/K_(m)为1000、CO_(2)吞吐采出程度增量达到2.0%时,S_(o)适应性界限为0.57。当S_(o)为0.500、CO_(2)吞吐换油率达到0.3时,K_(f)/K_(m)适应性界限为700;当S_(o)为0.548、CO_(2)吞吐换油率达到0.6时,K_(f)/K_(m)适应性界限为10。K_(f)/K_(m)-S_(o)图版可用于确定页岩油CO_(2)吞吐适应性的物性界限。研究结果对于CO_(2)吞吐现场试验方案设计和应用具有一定的指导意义。

基于粘附功计算的不同微形貌表面抗冰差异

超疏水表面的防水性与表面的微观结构直接相关,不同微观形貌将呈现不同的疏水性能,从而亦产生不同的防覆冰性。代表性的选择动植物叶片、翼片、金属与非金属等工程材料固体表面做结冰和覆冰粘附强度测试,结果表明表面材料、微观结构不同,疏水、覆冰粘附性能不一样。设计了几种不同表面微形貌模型仿真自然和人工疏水表面微结构,用高粗糙度维持复合润湿状态,以具有矩形微形貌的表面为例建立覆冰粘附功与表面固体份数的解析关系,并推及其它模型。据粘附功、固体份数和粗糙度计算,发现不同微形貌表面覆冰粘附功的差异,固体份数对粘附功的决定作用以及粗糙度对复合润湿态的维持。理论上提出了选择适合的微观形貌用于防冰的定性标准:高粗糙度,低固体份数,低粘附功。按粘附功从小到大顺序确定适合于防冰、除冰微形貌;从固体份数和粗糙度的大小关系予以证实。

Enhancement of catalytic activity by homo-dispersing S_2O_8^(2–)-Fe_2O_3 nanoparticles on SBA-15 through ultrasonic adsorption

Mesoporous superacids S2O82–-Fe2O3/SBA-15(SFS)with active nanoparticles are prepared by ultrasonic adsorption method.This method is adopted to ensure a homo-dispersed nanoparticle active phase,large specific surface area and many acidic sites.Compared with bulk S2O82–-Fe2O3,Br?nsted acid catalysts and other reported catalysts,SFS with an Fe2O3 loading of 30%(SFS-30)exhibits an outstanding activity in the probe reaction of alcoholysis of styrene oxide by methanol with 100%yield.Moreover,SFS-30 also shows a more excellent catalytic performance than bulk S2O82–-Fe2O3 towards the alcoholysis of other ROHs(R=C2H5-C4H9).Lewis and Bronsted acid sites on the SFS-30 surfaces are confirmed by pyridine adsorbed infrared spectra.The highly efficient catalytic activity of SFS-30 may be attributed to the synergistic effect from the nano-effect of S2O82–-Fe2O3 nanoparticles and the mesostructure of SBA-15.Finally,SFS-30 shows a good catalytic reusability,providing an 84.1%yield after seven catalytic cycles.

激光选区熔化Ti-6Al-4V合金的微纳压痕尺寸效应

目的研究不同状态激光选区熔化Ti-6Al-4V合金的纳米压痕尺寸效应。方法对原始态合金分别进行600、700、800、900℃退火处理,利用扫描电子显微镜观察原始态和4种退火态合金的显微组织。基于纳米压痕技术测量原始态及4种退火态合金的纳米硬度和弹性模量。基于比例试样阻力模型、Nix-Gao模型和Meyer定律对纳米硬度进行函数拟合。结果随着退火温度的升高,原始态组织从魏氏体逐渐演变为网篮组织。5种形态的Ti-6Al-4V合金的硬度和弹性模量均出现随压入深度的增加而减小的现象,表现出典型的压痕尺寸效应,基于试验测得的原始态及4种退火态合金的纳米硬度分别为3.66、4.36、3.96、3.88、4.77 GPa,弹性模量分别为113.1、125.2、102.1、100.3、108.7 GPa;基于比例试样阻力模型计算的纳米硬度分别为3.53、4.34、3.92、3.52、4.04 GPa;基于Nix-Gao模型计算的纳米硬度分别为3.68、3.94、4.07、3.85、4.47 GPa;基于Meyer定律拟合出的迈耶指数分别为1.75、1.86、1.82、1.80、1.81,均小于2,均表现为正压痕尺寸效应。结论激光选区熔化Ti-6Al-4V合金的硬度及弹性模量均有典型的压痕尺寸效应;3种模型均能较好地描述原始态和退火态合金的压痕尺寸效应,Nix-Gao模型直接建立了纳米硬度和压痕深度的关系,其拟合结果更接近于试验结果,计算的硬度值也最为准确。