The combined utilization of fiber-reinforced polymer (FRP) composites with coral aggregate concrete (CAC) in remote island areas contributes to the reduced construction cost and construction period, offering a promising application. However, the evolution pattern and deterioration mechanism of flexural behavior for FRP bars reinforced CAC beams in marine service environments remains unclear. Thus, this paper investigates the flexural behavior of basalt-FRP (BFRP) bars reinforced CAC beams under seawater immersion and dry-wet cycle conditions using laboratory-accelerated aging methods. The research considers the effects of exposure temperature and corrosion age on their failure modes, flexural stiffness, ultimate loading capacity, and deformation deflection. The experimental results revealed that with the increase in corrosion age and exposure temperature, the amount of vertical cracks of CAC beams decreased and their crack depth also exhibited a slight reduction, but their crack width and spacing at failure significantly increased. After being attacked by seawater environments, the load-deflection curves of CAC beams experienced an enhanced slope of the ascending section (i.e., flexural stiffness), but this strengthened flexural stiffness did not result in an enhancement in the ultimate load capacity. Instead, with prolonged corrosion and higher temperatures, the ultimate load of CAC beams displayed significant degradation, accompanied by reduced mid-span deflection. After 12 months of seawater exposure to wet-dry cycle conditions at 60 degrees C, the ultimate load and mid-span deflection of CAC beams degraded by approximately 25.0 % and 56.6 %, respectively. The study also predicted the flexural bearing capacity of CAC beams utilizing existing specifications for FRP-reinforced normal aggregate concrete (NAC). It was concluded that the formulae for flexural loading capacity for FRP-reinforced NAC beams were still suitable for CAC beams.

Li 2 O−Al 2 O 3 −SiO 2 (LAS) glass-ceramics were prepared by a melting method. Effects of different Al 2 O 3 content on the structure, crystallization, transmittance and fracture toughness of LAS glass-ceramics were investigated by means of XRD, FESEM and other methods as well. The results showed that the glass transition temperature and crystallization temperature of samples increased as the content of Al 2 O 3 increased from 4.1 wt% to 13.1 wt%, which restrained the precipitation of lithium disilicate crystals. The main crystalline phase of glass-ceramics transformed from lithium disilicate and petalite to silicon dioxide, which reduced the fracture toughness of glass-ceramics. When the Al 2 O 3 content was 7.1 wt%, the specimen had outstanding transmittance and fracture toughness. The transmittance was 90.32%. The fracture toughness was 1.13 MPa · m 1/2 . Compared with high-alumina glass, the fracture toughness of the glass-ceramic was greatly improved, and it could be used as a new type of protective material for mobile devices.

Detecting 1 ppm acetone at high humidity is essential for a noninvasive diabetes diagnosis. Metal oxide gas sensors are a promising technology to achieve high sensitivity acetone monitoring. Here, we fabricated Pt-sensitized In2O3 nanotubes, and the gas-sensing performance was tested against eight gases. The fiber structure contributes to the uniform dispersion of Pt onto the In2O3. Pt-sensitized In2O3 nanotubes have lower optimal operating temperatures and higher sensitivity and selectivity than those of the In2O3 nanotubes. The 0.75 wt % Pt-In2O3 sensor has the maximum sensitivity (113) to 10 ppm acetone at 300 degrees C; the response and response time to 1 ppm acetone are 19.9 and 10 s, respectively. The response to 1 ppm acetone still has 9.83 at the relative humidity of 83%. It also has a low limit of detection (8.4 ppb) and good long-term stability (30 days). These results illustrate that Pt sensitized nanotubes have the for a noninvasive diabetes

The hollow cylinders of TiB-Ti composites with a gradient distribution of Ti phase were synthesized by the combination of traditional slurry spray with centrifugal forming process. The influences of the concentration of sodium hexametaphosphate (SHMP), the concentration of polyvinyl alcohol (PVA) and solid content (20 vol%–35 vol%) on the rheological properties of the TiB2−Ti composite slurries were investigated. Slurries with low viscosity, weak thixotropy and shear-thinning behaviour were obtained for facilitating the slurry spraying process. The effects of different centrifugal conditions on the migration of components during the forming process were studied. The phase composition and the elements distribution of the prepared samples were characterized by the energy-dispersive X-ray spectrometer. The observations revealed that the samples fabricated at 1 500 r/min for 3 min had a significant composition variation. For two-phase systems with small density differences and large particle size variation, centrifugal time was more important than centrifugal speed in forming a continuous gradient structure.

The gaining effect of fibers with different scales on the crack resistance of concrete is different. Microscale fibers play an essential role in preventing cracking, while macro scale fibers mainly produce crack prevention effects during crack propagation. This paper aims to investigate the flexural static and fatigue performances of high-content hybrid fiber-polymer concrete (HCHFPC). The results show that the microstructure of HCHFPC is more compact than plain concrete (P.C.), the micro-cracks and holes are significantly reduced, and the flexural strength is about three times that of P.C. Through the test of the three-parameter Weibull distribution function, it was found that there is a good correlation between the fatigue life of each specimen. Based on this, a fatigue life prediction model with different failure probability (PSN) is established. Finally, by comparing the flexural fatigue performance of mainstream high-performance concrete, it is confirmed that HCHFPC has high toughness and flexural fatigue durability.

Nd3+-doped NaGdF4: Yb, Tm nanocrystals were synthesized by an improved high-temperature thermal decomposition method, and the effects of doping concentrations on the crystal structure, phase composition, and upconverted fluorescence intensity were also investigated. The results reveal that the introduction of Nd3+ ions does not cause the transformation of the crystal phase, but induce the change of the unit cell parameters. Meanwhile, the fluorescence intensity of the synthesized nanocrystals when co-doped with 3 mol% Nd3+. is the strongest under the excitation of 980 nm laser, which is 3.9 times that of the Nd3+-free doped nanoparticles, and the average size is 62.9 nm. And it is located in the blue area of the CIE coordinate diagram, and the corresponding color purity is 91.81% under the same experimental conditions. The resulting nanocrystals show the potential as excellent fluorescence labeling and in vivo imaging probes.

Unsaturated and extremely large magnetoresistance (MR), as well as the giant Nernst effect, are intriguing transport phenomena in Weyl semimetals, which are technically appealing for potential applications in magneto‐electric sensors and transverse thermoelectric conversion. The prominent properties are originated from Weyl semimetal states, i.e., the coexistence of electron and hole pockets combined with linear band dispersion. However, previous studies have been focused on small‐sized single crystals, rendering the practical applications of Weyl semimetals. Here, it is reported an unsaturated, quasi‐linear MR as well as a very large Nernst power factor PF xy in the prepared centimeter‐sized and polycrystalline Weyl semimetal NbP. An extraordinary MR of ≈2 × 10 4 % is observed below 60 K with a magnetic field up to 55 T and persists to elevated temperatures. The unusual quasi‐linear MR behavior is explained by the theory of classical linear MR arising from structural disorder. The polycrystalline NbP exhibits state‐of‐the‐art PF xy that reaches a maximum value of 74.81 μW cm –1 K –2 at 9 T and 220 K, which is 1.5 times larger than its longitudinal thermoelectric power factor PF xx . Given that polycrystalline Weyl semimetal, NbP is suitable for large‐scale production, the results pave the way for its practical applications in magneto‐electric sensors and transverse thermoelectric conversion.

Nd 3+ -doped NaGdF 4 :Yb,Tm nanocrystals were synthesized by an improved high-temperature thermal decomposition method,and the effects of doping concentrations on the crystal structure,phase composition,and upconverted fluorescence intensity were also investigated.The results reveal that the introduction of Nd 3+ ions does not cause the transformation of the crystal phase,but induce the change of the unit cell parameters.Meanwhile,the fluorescence intensity of the synthesized nanocrystals when co-doped with 3 mol% Nd 3+ is the strongest under the excitation of 980 nm laser,which is 3.9 times that of the Nd 3+ -free doped nanoparticles,and the average size is 62.9 nm.And it is located in the blue area of the CIE coordinate diagram,and the corresponding color purity is 91.81% under the same experimental conditions.The resulting nanocrystals show the potential as excellent fluorescence labeling and in vivo imaging probes.

为了提高LaFeO3催化剂同时净化NO和碳烟性能,采用溶胶-凝胶法,以柠檬酸为络合剂制备了具有纳米结构的LaFe1-x NixO3钙钛矿催化剂.通过X射线衍射(XRD)对催化剂进行表征分析,结果表明溶胶-凝胶法制备的LaFe1-x NixO3催化剂形成了很好的LaFeO3钙钛矿结构.利用固定床微型反应器评价催化活性,结果表明Ni掺杂能够提高LaFeO3催化剂的催化性能,其中LaFe0.9Ni0.1O3催化剂具有最佳催化活性,其碳烟起燃温度(Tig)为260℃,碳烟最大燃烧速率温度(Tmax)为420℃,NO的最大转化率(ηmax)为26.05％.表明Ni掺杂改性的LaFe0.9Ni0.1O3催化剂具有良好的同时净化NO和碳烟性能.

The normal triply periodic minimal surface (TPMS) is often used to design homogeneous or graded porous bone tissue, but the porous structure based on deformed TPMS has good mechanical properties in certain space direction. For simplify design process, a porous structure design method based on deformed TPMS is proposed. Deformed TPMS unit cell is designed with changing the magnitude factor of the TPMS trigonometric function expression. Exploring the influence of magnitude factor and threshold on the porous structure shape and porosity, and establishing the relationship between the pore characteristic parameters and the mathematical parameters, a parametric design method for deformed TPMS porous structure is investigated. This method implemented in the Grasshopper plugin of Rhinoceros, the porous structures with different porosity are designed. The results indicate the method can control the pore shape and porosity of the porous structure, and the design error is within the allowable range and conforms to the bone tissue porous structure design requirements.

Two-dimensional montmorillonite nanolayers (2D Mnt) are excellent adsorbents for methylene blue due to the fully exposed active sites, but the separation of 2D Mnt from water is difficult. The objective of the present study was to assemble 2D Mnt and graphene oxide sheets into a three-dimensional aerogel (3D Mnt-rGO Gel) to achieve easy solid–liquid separation. Structural characterization demonstrated that the Mnt-rGO Gel has a porous 3D structure with Mnt nanolayers distributed uniformly within; the introduction of 2D Mnt could reduce significantly the degree of restacking of graphene sheets. Adsorption tests indicated that 2D Mnt enhances the methylene blue (MB) removal performance of Mnt-rGO Gel with a large adsorption capacity of 207 mg g–1, which may be attributed to the adsorption of MB onto 2D Mnt and the increased adsorption surface of rGO resulting from the reduced restacking of graphene sheets. The MB was removed completely by 300 mg L–1 of Mnt-rGO Gel-3 in 180 min. The adsorption process of MB onto Mnt-rGO Gel followed the pseudo-second order kinetic model and the Langmuir isotherm model. Mnt-rGO Gel also showed good reusability. Fourier-transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS) results suggested that the adsorption of MB onto Mnt-rGO Gel may be attributed to the π–π interactions between aromatic rings of MB and graphene, hydrogen bonding, and the electrostatic interactions between the nitrogen groups on the MB and oxygen-containing groups on the Mnt-rGO Gel.

相较于碱性石料,作为酸性集料的安山岩与沥青黏附性较差,直接用于路面铺筑将严重影响沥青路面的使用寿命和路用性能.通过在安山岩沥青混合料掺加改性剂,提高混合料中安山岩与沥青的黏附性,满足路用性能要求.为了研究酸性安山岩集料中抗剥落剂的最佳掺量,基于表面能原理,采用插板法和蒸汽吸附法测量SBS改性沥青和酸性安山岩集料的表面能参数,计算沥青与集料表面能黏附性指标ER值,确定添加的抗剥落剂最佳掺量为0.4％;通过沥青混合料宏观水稳定性试验发现抗剥落剂掺量0.4％ 时,浸水残留稳定度比和冻融劈裂强度比达到最大,从而验证了ER值指标的可靠性,并建立ER值与水稳定性指标的联系.

在SBR(Ⅰ)反应器中快速启动颗粒-絮状污泥耦合单级自养脱氮系统,研究启动前后颗粒、絮状污泥脱氮性能的变化.取启动前和系统构建成功后的污泥进行批试实验,通过甲醇抑制厌氧氨氧化菌(AAOB)活性来研究厌氧氨氧化和反硝化比例的变化.絮状污泥总氮去除率(NRE)从启动前的10.14％提高至启动成功后的89.70％,其中厌氧氨氧化脱氮占比从2.23％提高到83.70％,反硝化脱氮占比从7.91％减少到5％～6％;颗粒污泥的NRE从启动前3.90％提高至启动成功后的83.20％,厌氧氨氧化占比从不足1％提高到80.20％左右,反硝化占比从7.72％减少到2％～3％.

为研究汽车火灾对大跨度钢桁架拱桥结构受力性能的影响,以主跨为240 m的某下承式钢桁架拱桥为研究对象进行受火分析计算.首先利用火灾模拟软件FDS对两种典型火灾场景进行数值模拟获得火灾温度场分布,然后通过有限元瞬态热分析确定火灾区域构件的温度分布,再通过ABAQUS热-结构耦合分析桥梁在不同火灾场景下结构性能的变化.结果表明:钢桁架拱肋在油罐车火灾作用下受火构件的最高温度达540℃;主要传力构件在温度为430℃时屈服,达到承载能力极限状态,热膨胀效应与内力重分布导致附近构件的应力增幅达60～180 MPa;桥面竖向位移变化最大为115 mm,最大横向高差为108 mm.油罐车火灾主要对火源附近3根吊索的温度场产生影响,受火吊索索力减小使得桥面下挠33 mm,主梁应力增大35 MPa.

接种好氧絮状污泥于SBR反应器中,先快速启动短程硝化,然后进行半短程硝化调控并分析阶梯式降温下功能菌群落结构变化.结果 表明,控制ρ(DO)为1.2～1.5 mg·L-1、pH值为7.6～7.7、温度为(30±2)℃时,在第16天成功启动短程硝化.随后进行半短程硝化调控,使出水NO2--N/NH4+-N比值稳定在1.32左右.然后进一步设置阶梯式降温(28℃→25℃→20℃→15℃)的实验工况,通过提升ρ(DO)为1.4～1.5 mg· L-1、进水pH值为7.8～7.9,使反应器在中低温下保持稳定运行,在15℃条件下NH4+-N去除率(NRR)均值为59.7％,NO2--N积累率(NAR)均值达80.2％.16S rDNA高通量测序检测显示,氨氧化菌(AOB)菌属Nitrosomonas占比由接种污泥中的0.09％上升到15℃下的5.20％,菌属丰度提升了58倍左右.亚硝酸盐氧化菌(NOB)菌属Nitrospira和Nitrobacter占比分别由接种污泥的0.90％和0.98％下降到15℃下的0.33％和0.05％,AOB丰度明显增加,NOB得到有效抑制.

为了研究溶解氧对SBR单级颗粒污泥自养脱氮系统的影响,基于活性污泥ASM3模型和短程硝化-硝化-反硝化模型,将颗粒污泥传质过程与氨氧化菌(AOB)、厌氧氨氧化菌(AAOB)、亚硝酸盐氧化菌(NOB)、反硝化菌(DNF)的生长过程、好氧内源呼吸及缺氧内源呼吸过程等耦合,建立了单级自养脱氮颗粒污泥动力学模型,并对颗粒内部基质浓度分布进行预测.结果显示,当DO为0.4mg/L时,好氧区和缺氧区(厌氧区)的比例为0.4:1;当DO为0.6mg/L时,颗粒污泥好氧区与缺氧区(厌氧区)的比例为3:1.同时,根据基质反应速率方程,建立了颗粒污泥的单级自养脱氮系统动力学模型,对SBR系统运行效果进行预测,结果显示,DO为0.6mg/L时,氨氮反应完全,亚硝酸盐氮和硝酸盐氮在5mg/L以下,总氮去除率模拟值为89％左右,略低于实际测量脱氮率95％.

接种厌氧氨氧化颗粒、絮状混合污泥于SBR反应器中.通过调控pH值、温度等参数,实现厌氧氨氧化稳定运行,针对系统失稳现象采取合理策略使其快速恢复,并探究缩短水力停留时间(HRT)对功能菌胞外聚合物(EPS)和系统脱氮性能的影响,分析不同阶段污泥形态变化.结果表明:1～78 d平均出水NH+4-N,NO-2-N质量浓度仅为0.34,0.81 mg/L,总氮去除负荷(NRR)在0.25～0.33(kg·N)/(m3·d)之间,总氮去除率(NRE)稳定在94.5％以上,系统运行高效.并针对79～178 d系统运行出现的间断失稳现象,通过系统原位清洗、降低系统氮容积负荷(NLR)等策略,迅速恢复脱氮性能.在HRT缩短过程(179～222 d)中,功能菌EPS中蛋白质(PN)/多糖(PS)由197 d的1.35升至213 d的1.86,222 d达到2.08,有效促进污泥颗粒化.逐渐缩短HRT(12 h→8 h→6 h),当HRT值=6 h时,NRR平均值达到0.58(kg·N)/(m3·d),NRE均值维持在94.2％,脱氮性能保持稳定.

为探究组合启动模式实现厌氧氨氧化反应器高效启动和稳定运行的可行性,分别采用接种短程硝化污泥结合提高进水基质(A)和接种厌氧氨氧化污泥结合缩短水力停留时间(B)2种组合方式启动改良型UASB厌氧氨氧化反应器,对反应器启动效果进行研究,并通过改变进水基质比和低温冲击探究启动成功后的反应器性能.结果 表明:A反应器启动成功时的总氮去除负荷(NRR)为0.520 kg·(m3·d)-1、亚硝化单胞菌Nitrosomonas相对丰度大幅下降、主要厌氧氨氧化菌属由Candidatus Kuenenia转化为Candidatus Brocadia;而B反应器NRR达到1.950 kg·(m3·d)-1、Candidatus Kuenenia始终为优势菌属.随着进水基质比的提高,B反应器的NRR和上升幅度始终高于A反应器,具有更强的抗负荷能力.当温度由35℃下降至15℃时,A和B反应器污泥对基质的降解速率分别下降92.94％和81.38％;温度恢复至35℃后,A反应器污泥降解速率的回升率大于B反应器污泥.因此,接种厌氧氨氧化污泥和缩短水力停留时间的组合方式更有利于改良型UASB厌氧氨氧化反应器的高效启动和稳定运行.

By using solution combustion synthesis method,delafossite catalyst LiCo0.9 O2 were pre-pared to purify the diesel engine pollutants.By small sample experiment,the effect of catalyst addi-tives,multiple coating,and the NTP coordination on the purification of PM and NOx were analyzed. It is indicated that the addition of TiO2 ,La2 O3 ,and CeO2 as catalyst additives can improve the con-version ratio of NOx to 17.6%.Multiple coating of the catalyst can improve the conversion ratio of NOx to 17.8%.NTP coordination can significantly improve the purification effect of diesel engine PM and NOx.Under the condition of 30 kV and 50 Hz,combining the prepositive plasma with the catalyst LiCo0.9 O2 ,the purification rate of NOx can reach 25.0%.

通过测试水浸泡前后蓄盐沥青混凝土表面结冰点、冰层粘附力以及浸泡液的电导率,研究了雨水对蓄盐沥青路面自融冰性能影响.结果表明:经水浸泡后蓄盐沥青混凝土的表面结冰点升高、与冰层之间的粘附力增大,其中内掺纯氯化钠的沥青混凝土在浸泡8h后,其表面结冰点及其与冰层粘附力已与普通沥青混凝土相近,而内掺包覆氯化钠融冰剂的沥青混凝土还具有一定的自融冰性能.浸泡液电导率测试表明,内掺6％纯氯化钠的蓄盐沥青混凝土和内掺6％包覆氯化钠融冰剂的蓄盐沥青混凝土浸泡4h后,氯化钠析出量分别为42.70 g/m2和17.23 g/m2.氯化钠经包覆处理后,减少了其从沥青混凝土中溶出量,但溶出的氯化钠仍对沥青混凝土和环境有一定的影响.