Construction of Self-Assembly Based Tunable Absorber:Lightweight,Hydrophobic and Self-Cleaning Properties

Although multifunctional aerogels are expected to be used in applications such as portable electronic devices,it is still a great challenge to confer multifunctionality to aerogels while maintaining their inherent microstructure.Herein,a simple method is proposed to prepare multifunctional NiCo/C aerogels with excellent electromagnetic wave absorption properties,superhydrophobicity,and self-cleaning by water-induced NiCo-MOF self-assembly.Specifically,the impedance matching of the three-dimensional(3D)structure and the interfacial polarization provided by CoNi/C as well as the defect-induced dipole polarization are the primary contributors to the broadband absorption.As a result,the prepared NiCo/C aerogels have a broadband width of 6.22 GHz at 1.9 mm.Due to the presence of hydrophobic functional groups,CoNi/C aerogels improve the stability in humid environments and obtain hydrophobicity with large contact angles>140°.This multifunctional aerogel has promising applications in electromagnetic wave absorption,resistance to water or humid environments.

Green Superhydrophobic Paper with Self-cleaning Properties Prepared via One-step Impregnation

In this study,a green and pollution-free multifunctional superhydrophobic paper-based material was prepared using a simple and efficient dipping method.The superhydrophobic paper with a water contact angle(WCA)of 160°was prepared by attaching micro-and nanocomposite particles,made of stearic acid-modified chitosan and two kinds of titanium dioxide(TiO_(2))nanoparticles of different sizes,to a paper substrate.The surface morphology,elemental composition,and wetting properties of the coatings were examined using scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),Fourier transform infrared spectroscopy(FT-IR),and contact angle measurements.Additionally,superhydrophobic coatings exhibited good self-cleaning properties,liquid repellency,ease of repair,and antifouling properties in organic solutions.

Facile preparation and efficient MnxCoy porous nanosheets for the sustainable catalytic process of soot

The pursuit of high-performance is worth considerable effort in catalysis for energy efficiency and environmental sustainability. To develop redox catalysts with superior performance for soot combustion, a series of Mn_(x)Co_(y) oxides were synthesized using MgO template substitution.This method greatly improves the preparation and catalytic efficiency and is more in line with the current theme of green catalysts and sustainable development. The resulting Mn_(1)Co_(2.3) has a strong activation capability of gaseous oxygen due to a high concentration of Co^(3+) and Mn^(3+). The Mn doping enhanced the intrinsic activity by prompting oxygen vacancy formation and gaseous oxygen adsorption. The nanosheet morphology with abundant mesoporous significantly increased the solid–solid contact efficiency and improved the adsorption capability of gaseous reactants. The novel design of Mn_(1)Co_(2.3)oxide enhanced its catalytic performance through a synergistic effect of Mn doping and the porous nanosheet morphology, showing significant potential for the preparation of high-performance soot combustion catalysts.

Evaluation of the Oxidation Reactivity and Behavior of Exhaust Soot Particles from Diesel Engines with Different Emission Levels

The aim of this study was to investigate the oxidation reactivity and behavior of exhaust particulate matter(PM)from diesel engines.PM samples from two diesel engines(1K,CY4102)with different emission levels were collected by a thermophoretic system and a quartz filter.The oxidation reactivity,oxidation behaviors,and physicochemical properties of the PM samples were analyzed using thermogravimetric analysis(TGA),high-resolution transmission electron microscopy(HRTEM),Fourier-transform infrared spectrometry(FTIR),and Raman spectroscopy.The results showed that there was a great difference in the oxidation reactivity of soot particles emitted by the two different diesel engines.A qualitative analysis of the factors influencing oxidation reactivity showed that the nanostructure,degree of graphitization,and relative concentration of aliphatic C—H functional groups were the most important factors,whereas no significant correlation was found between the primary particle size and activation energy of the diesel soot.Based on the oxidation behavior analysis,the diesel soot particles exhibited both internal and surface oxidation modes during the oxidation process.Surface oxidation was dominant during the initial stage,and as oxidation progressed,the mode gradually changed to internal oxidation.Internal oxidation mode of soot particles from the 1K engine was significantly higher than that of CY4102.

Comparative Study of Structure and Property Changes in Corrosive Media for Self-cleaning Superhydrophobic Magnesium Alloys

Magnesium alloys with superhydrophobicity are constructed by controlling rough surface structure and grafting long hydrophobic alkyl chains. Changes of morphology, phase structure, chemical composition as well as wettability, corrosion resistance of superhydrophobic magnesium alloy upon immersing in corrosive media are investigated comparatively. Meanwhile, the contaminating particles on as-prepared superhydrophobic surfaces can be taken away easily by rolling water droplets. Therefore, the results show that as-prepared superhydrophobic magnesium alloys exhibit enhanced corrosion resistance and self-healing performance. Finally, anti-corrosion and self-cleaning mechanisms are deduced. It can be concluded that it is an effective strategy of preparing superhydrophobic surfaces for improving the corrosion resistance and selfcleaning performance of magnesium alloys.

Self-cleaning glass coated with Fe^(3+)-TiO_2 thin film

The self-cleaning glass coated with Fe3+-TiO2 photocatalytic thin film was prepared by sol-gel process from the system Ti（OC4H9）4-NH（C2H4OH）2-C2H5OH-H2O containing FeCl3. The microstructure and properties of the film were studied using differential thermal analysis-thermogravimetry（DTA-TG）, X-ray diffration（XRD） and scanning electron microscope（SEM）. The transmittance of the self-cleaning glass was measured by using UV-Vis spectrometer. The effects of content of Fe3+ and the thickness of Fe3+-TiO2 thin film on the photocatalytic activity were examined. The results show that the photocatalytic thin films are mainly composed of Fe3O4 and TiO2 particles within 10100 nm. The appropriate amount of Fe3+ is effective for improving the photocatalytic activities of TiO2. The best photocatalytic activity is obtained when the molar ratio of Fe3+ to TiO2 is 0.005 and the glass is coated with 9 layers.

Superhydrophobic Micro/Nanostructured Copper Mesh with Self-Cleaning Property for E ective Oil/Water Separation

In this work, a simple method was carried out to successfully fabricate superoleophilic and superhydrophobic N-dodecyltrimethoxysilane@tungsten trioxide coated copper mesh. The as-fabricated copper mesh displayed prominent superoleophilicity and superhydrophobicity with a huge water contact angle about 154.39° and oil contact angle near 0° Moreover, the coated copper mesh showed high separation efficiency approximately 99.3%, and huge water flux about 9962.3 L·h^-1·m-2, which could be used to separate various organic solvents/ water mixtures. Furthermore, the coated copper mesh showed favorable stability that the separation efficiency remained above 90% after 10 separation cycles. Benefiting from the excellent photocatalytic degradation ability of tungsten trioxide, the coated copper mesh possessed the self-cleaning capacity. Therefore, the mesh contaminated with lubricating oil could regain superhydrophobic property, and this property of self-cleaning permitted that the fabricated copper mesh could be repeatedly used for oil and water separation.

Self-Cleaning Properties of Vanadium Doped TiO₂Sol-Gel Derived Thin Films

In this study, vanadium doped TiO2 thin films were deposited on glass substrates using a sol-gel dip-coating process. X-Ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and UV-Vis spectrophotometer were used to characterize the structural, chemical and the optical properties of the thin films. The photo-catalytic activities of films were investigated by methylene blue degradation. Water contact angle on the film surfaces was measured by a water contact angle analyzer. The results indicated that vanadium doping had a significant effect on the self-cleaning properties of TiO2 thin films.

A simple way to fabricate an aluminum sheet with superhydrophobic and self-cleaning properties

A superhydrophobic aluminum sheet is fabricated via a hot water immersing process and subsequently surface modification with heptadecafluorodecyltrimethoxy-silane （HTMS）. As revealed by the scan electron microscopy （SEM）, X-ray diffraction （XRD）, and Fourier-transform infrared spectrophotometer （FTIR） results, a rough pseudoboehmite film is formed on the aluminum sheet, and HTMS molecules are grafted on the film surface successfully. These two factors make the treated aluminum sheet present superhydrophobicity with a water contact angle larger than 160° and sliding angle less than 5°, and possess a self-cleaning property. Furthermore, the flexible superhydrophobic aluminum sheet could be pasted to a cylinder surface without destroying its superhydrophobicity. At the end, the effect of hot water treatment time on superhydrophobicity is investigated.

Super-hydrophobic and Self-cleaning PVDF Film Fabricated by Chemical Bath Deposition

Self-cleaning surfaces have received a great deal of attention recently,both in theoretical studies and commercial applications.The self-cleaning surface of lotus leaf is hydrophobic and rough,showing a micro-and nano-scale morphology.The micro-reliefs of lotus leaf were mimicked using polyvinylidene fluoride(PVDF)film and nano-scale peaks on the top of the micro-reliefs were implemented by the reaction between methyltrichlorosilane and the reactive groups of PVDF film treated by oxygen plasma.A lotus-leaf-like surface of the PVDF film was clearly observed by scanning electronic microscopy(SEM)and atomic force microscope(AFM).Elemental composition analysis by X-ray photoelectron spectroscopy(XPS)revealed that the material of the nanostructure of PVDF film was polymethylsiloxane.The superhydrophobic property of the mimicked self-cleaning surface was validated by the water contact angle and sliding angle on the lotus-leaf-like PVDF film,which were 156.6° and 4°,respectively.In this case,water droplets can easily move across the PVDF film surface,carrying dirt particles away,leaving no contamination.

Self-cleaning performance of a self-cleaning pre-coated steel sheet in an industrial environment

A type of self-cleaning pre-coated steel sheet with excellent self-cleaning performance was developed using hydrophilic surface treatment technology. To understand the self-cleaning properties of this pre-coated steel sheet in an industrial environment, the Jiangjin natural environmental test station was chosen as the outdoor exposure test to be conducted, and the self-cleaning performance of the steel sheet was studied by measuring the water contact angle, stain resistance factor, color difference, and gloss of the steel sheet during the outdoor exposure test. The water contact angle of the self-cleaning steel sheet quickly decreased from 84° to 29° during the outdoor exposure test, and the steel sheet showed excellent hydrophilic properties, which were beneficial to the spread of rain drops and detrimental to the accumulation of the surface pollutants. After an outdoor exposure of 12 months,the self-cleaning steel sheet had a higher stain resistance and cleaner surface than the comparison sample sheet, demonstrating its excellent self-cleaning properties. Moreover, the color difference and gloss rate of the self-cleaning steel ＇sheet were similar to those of the pre-coated steel sheet without hydrophilic surface treatment. Therefore, the hydrophilic surface treatment technology used in this study did not affect the anti-aging property of the self-cleaning steel sheet.

Rendering of Cellulose Acetate Fabrics Self-Cleaning through Treatment with TiO₂Nano Particles

Finishing using TiO2-nanosol treatment of cellulose acetate (CA) fabrics before and after the latter were pretreated with H2O2was undertaken with a view to impart unique properties to CA fabrics, notably, self-cleaning. Finishing was performed as per the pad-dry-cure method. The finishing treatment involved dispersing the nano-sized TiO2particles in a mixture of water and ethylene glycol (1:1) and application of the dispersions to CA fabrics was made under a variety of conditions. Self cleaning ability of the fabrics is favored by 1) increasing the concentration of TiO2-nanosol to certain limit;2) prolongation of curing time up to 15 second;3) raising the microwave power from 80% to 100% but with the certainty that power of 90% is the most proper. Besides, exposure time-to UV radiation-up to 90 minutes is essential to have remarkable self cleaning properties while keeping other technical properties, namely, strength, roughness and wettability practically unaltered. Incorporation of binder in the finishing pad-bath helps stabilizing the deposition of TiO2 with excellent self-cleaning. Pretreatment of CA fabrics with H2O2 is a pre requisite to guarantee excellent self-cleaning ability. Thermofixation and microwave fixation produces fabrics with very comparable technical properties.

A Review on Self-Cleaning Coatings for Tunnels

Self-cleaning coatings for tunnels can effectively remove dust and stains accumulated over the surface of tunnel linings and their appurtenances due to the closed environment and poor ventilation.This paper systematically introduces the current research status of self-cleaning coatings for tunnels,focusing on the development of super-hydrophobic self-cleaning coatings,superamphiphobic self-cleaning coatings,exhaust gas degradation coatings,fire retardant coatings,and tunnel de-icing coatings.The advantages and disadvantages of the five functional coatings are then briefly described,and the problems of self-cleaning coatings for tunnels at the present stage are pointed out.Finally,the development direction of self-cleaning coatings for tunnels is proposed to provide a reference for the research and application of self-cleaning coatings for tunnels.

大缸径柴油机燃烧系统优化模拟

为提高某缸径200 mm船用发电柴油机的燃油经济性,本文设计了活塞燃烧室和燃油喷射系统的升级方案并进行了模拟优化。升级方案提高了压缩比和燃油喷射压力,采用大径深比浅ω燃烧室配合158°喷油夹角喷油嘴。对不同方案下发动机的缸内工作过程进行了计算流体力学模拟,计算了高压指示功和放热率相位,分析了缸内温度、反应过量空气系数和速度分布及演化。模拟结果表明:升级方案能够提高发动机热效率。增加喷孔数并减小孔径,可以在保持NOx排放基本不变的条件下提高高压指示功4.5%,降低碳烟排放约60%。采用“平顶”浅ω燃烧室与158°喷油夹角喷雾配合,油气混合气快速进入余隙并形成逆时针的漩涡流动,能够加速油气混合和燃烧过程,提高热效率。

高原环境下重型车辆排放物生成机制分析

针对高原环境下重型车辆排放物生成机制尚不清晰的问题,以1辆搭载国六重型柴油发动机的车辆作为研究对象,在海拔2 400 m左右高原环境下,利用便携式排放测量系统(PEMS)设备,对不同负荷工况车辆冷启动过程排放污染物的瞬态变化趋势进行了研究。结果表明,受高原稀薄空气的影响,运行前期,车辆在高负荷工况下CO排放更高,且与10%和50%负荷不同,100%负荷下,NOx、NO和NO2排放峰值主要出现在运行时间300~500 s;在高负荷工况下,车辆碳烟颗粒排放量高,但水温增加后,碳烟颗粒排放迅速下降。冷起动过程中CO、NOx和碳烟颗粒数量浓度(PN)仍是排放污染物控制的关键项目,特别是在高原环境下。

超低剂量CI-415W-40柴油机油的研制及应用

基于我国社会经济和汽车工业的发展现状,未来一段时间内,市场中高、中、低档柴油机油将保持并存的局面,CI-4柴油机油仍是市场的主体,占有30%以上的份额。因此,为提高CI-4柴油机油性价比,优选以性能优异的金属清净剂、无灰分散剂和抗氧抗腐、抗磨剂等研制的复合剂,以8.3%的加剂量应用于适宜的基础油中,所调制的CI-415W-40柴油机油通过了Mack T-8E、Cat.1K、Cat.1P、程序ⅢF、Mack T-12、RFWT、EOAT和Cummins ISM等发动机台架试验,产品质量满足API CI-415W-40柴油机油标准的要求,并可实现6万km换油。

正十二烷喷雾火焰中碳烟的瞬态生成特性

针对压燃式发动机中碳烟演化过程难以被实验准确捕捉的问题,研究了高温高压环境中正十二烷喷雾燃烧焰中碳烟瞬态生成特性及动力学行为,在实验方面,应用消光辐射联合技术以及燃烧成像测速技术,同步获得高温高压环境中单孔喷油器正十二烷喷雾燃烧火焰中的碳烟体积分数、碳烟温度和碳烟速度场的瞬态分布;数值计算方面,基于OpenFOAM环境,发展欧拉喷雾模型和非稳态火焰面进度变量湍流燃烧模型的耦合模型,喷雾燃烧过程的数值计算结果与实验数据有高度的一致性。研究结果表明:相比于参考工况,低喷油压力工况火焰浮起长度更短,碳烟在当量比Φ>2区间驻留时间更长,推动了碳烟的生成,碳烟峰值质量增加了80%;高温环境工况碳烟在当量比Φ>2区间驻留时间没有明显差异,但更短的火焰浮起长度使得燃料在更高的当量比开始燃烧,导致其碳烟峰值质量增加了88%;富氧工况的燃烧温度最高,碳烟粒子运动速度增大,使得碳烟在当量比Φ>2区间驻留时间明显减少,同时火焰内部当量比较小,因而碳烟峰值质量减少了42%。

浅析1000MW二次再热塔式锅炉蒸汽吹灰系统设计

以1000MW超超临界二次再热塔式锅炉为例,对锅炉蒸汽吹灰系统进行了介绍,对吹灰器布置特点、汽源选择和管路系统的特点进行了介绍。

铅烟灰两段混合酸浸工艺回收铟资源的研究

为解决现行铅烟灰提取铟过程中浸出率低和安全环保问题,提出一种全湿法铅烟灰两段混合酸浸回收铟新工艺。研究铅烟灰浸出过程中硫酸浓度、液固比、反应时间和不同硫酸始酸浓度条件下盐酸对铟浸出率的影响。结果表明,控制铅烟灰一段浸出工艺条件为:液固比8∶1,硫酸始酸浓度150 g/L,盐酸始酸浓度40 g/L,反应温度90℃,反应时间4 h;二段浸出工艺条件为:液固比4∶1,硫酸始酸浓度300 g/L,盐酸始酸浓度40 g/L,反应温度90℃,铟浸出率达到81.18%,浸出渣含铟0.25%,且产出低酸浸出液符合净化工序要求。铅烟灰两段混合酸浸工艺工业应用后,每年可增产粗铟约3.63 t,增加经济效益约553.61万元,该工艺极具推广价值。