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Chinese Journal of Chemical Engineering 2018年第10期26卷 2199-2205页

作者： Hongyan Shen youzhi Liu Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering College of Chemical Engineering and Environment North University of China

Hydrophobic magnesium hydroxide(MH) nanoparticles were prepared by a one-step synthesis method in a high-gravity environment generated by a novel impinging stream–rotating packed bed(IS-RPB) reactor. The reactant solutions were simultaneously and continuously pumped into the IS-RPB reactor, and then Tween80 was added as a surface modifier. The morphology, structure, and properties of blank and hydrophobic MH were characterized. The effects of MH nanoparticles on the flame retardancy, thermal stability, and mechanical properties of PP/MH composites were also studied. We found that the obtained MH nanoparticles exhibited hexagonal lamella with a mean size of 30 nm, excellent hydrophobic properties(e.g., high water contact angle of 112°), and improved thermal stability of MH. The limiting oxygen index(LOI) further showed that increased MH loading can significantly improve flame-retardant performance, which reached 29.3% for PP/MH composites with 30 wt% hydrophobic samples. The thermal stability and mechanical properties of the PP/MH composites with hydrophobic samples were also much higher than those of PP/MH composites with blank MH. Results showed that the one-step synthesis had high potential application in the large-scale production of hydrophobic MH nanoparticles.

关键词： Magnesium hydroxide Synthesis Polypropylene Hydrophobic property Rotating packed bed

Degradation of nitrobenzene-containing wastewater by sequential nanoscale zero valent iron-persulfate process

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Green Energy & Environment 2021年第6期6卷 910-919页

作者： Jingjuan Qiao Weizhou Jiao youzhi Liu Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering North University of ChinaTaiyuanShanxi030051China

As nitrobenzene(NB)is structurally stable and difficult to degrade due to the presence of an electron withdrawing group(nitro group).The sequential nanoscale zero valent iron-persulfate(NZVI-Na_(2)S_(2)O_(8))process was proposed in this study for the degradation NB-containing *** results showed that the NB degradation efficiency and the total organic carbon removal efficiency in the sequential NZVINa_(2)S_(2)O_(8)process were 100%and 49.25%,respectively,at a NB concentration of 200 mg L^(-1),a NZVI concentration of 0.75 g L^(-1),a Na_(2)S_(2)O_(8)concentration of 26.8 mmol L^(-1),an initial pH of 5,and a reaction time of 30 min,which were higher than those(88.53%and 35.24%,respectively)obtained in the NZVI/Na_(2)S_(2)O_(8)*** radicals(SO_(4)·-)and hydroxyl radicals(·OH)generated in the reaction were identified directly by electron paramagnetic resonance spectroscopy and indirectly by radical capture experiments,and it was shown that both SO_(4)^(·-)and·OH played a major role in the sequential NZVI-Na_(2)S_(2)O_(8)*** possible pathways involved in the reduction of NB to aniline(AN)and the further oxidative degradation of AN were determined by gas chromatography-mass spectrometry.

关键词： Nanoscale zero valent iron Impinging stream-rotating packed bed Sequential NZVI-Na2S2O8process Nitrobenzene Degradation pathways

In situ synthesis of hydrophobic magnesium hydroxide nanoparticles in a novel impinging stream-rotating packed bed reactor

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Chinese Journal of Chemical Engineering 2016年第9期24卷 1306-1312页

作者： Hongyan Shen youzhi Liu Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering College of Chemical Engineering and Environment North University of China

Hydrophobic Mg(OH)_2nanoparticles were successfully synthesized via an in situ surface modification method in a novel impinging stream-rotating packed bed(IS-RPB) reactor using oleic acid(C_(17)H_(33)COOH, OA) as a surface modifier, magnesium chloride hexahydrate in the presence of ethanol as a precursor, and sodium hydroxide as a precipitant. The products were characterized by Fourier transform infrared spectroscopy(FTIR), Field emission scanning electron microscopy(FESEM), X-ray diffraction(XRD), and thermogravimetry-differential scanning calorimetry(TG-DSC). Compatibility with organic solutions was determined by sedimentation tests. The prepared nanoparticles exhibited regular hexagonal lamella with an average diameter of 30 nm when OA is added to the reaction system; this result indicates that OA regulates the morphology of the Mg(OH)_*** revealed that the high-purity Mg(OH)_2product presents a brucite structure, and the I_(001)/I_(101) of hydrophobic Mg(OH)_2(0.86) was higher than that of the blank Mg(OH)_2(0.63). FTIR analysis showed that OA bonded to the surface of the Mg(OH)_2. Compared with the blank Mg(OH)_2product, the product obtained through the proposed method possesses excellent hydrophobic properties, including a high water contact angle of 101.4° and good compatibility with liquid paraffin. TG-DSC analysis indicated that the total percentage of mass loss of hydrophobic Mg(OH)_2(40.88%) was higher than that of the blank Mg(OH)_2product(33.18%). The in situ surface modification method proposed in this work presents potential use in the large-scale production of Mg(OH)_2nanoparticles.

关键词： Nanoparticles Preparation Surfactants Magnesium hydroxide Precipitation

Investigation of hydroxyl-terminated polybutadiene propellant breaking characteristics and mechanism impacted by submerged cavitation water jet

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Defence Technology（防务技术） 2024年第3期33卷 559-572页

作者： Wenjun Zhou Meng Zhao Bo Liu youzhi Ma youzhi Zhang Xuanjun Wang Zhijian Laboratory Rocket Force University of EngineeringXi’an710025China

A submerged cavitation water jet(SCWJ)is an effective method to recycle solid propellant from obsolete solid engines by the breaking *** propellant's breaking modes and mechanical process under SCWJ impact are *** study aims to understand those impact breaking *** hydroxyl-terminated polybutadiene(HTPB)propellant was chosen as the research material,and a self-designed test system was used to conduct impact tests at four different working *** high-speed camera characterized crack propagation,and the DIC method calculated strain change during the impact ***,micro and macro fracture morphologies were characterized by scanning electron microscope(SEM)and computed tomography(CT)*** results reveal that the compressive strain concentration region locates right below the nozzle,and the shear strain region distributes symmetrically with the jet axis,which increases to 4% at first 16th ms,the compressive strain rises to 2% and 6% in the axial and transverse direction,*** two tensile cracks formed first at the compression strain concentrate region,and there generate many shear cracks around the tensile cracks,and those shear cracks that develop and aggregate cause the cracks to become wider and cut through the tensile cracks,forming the tensile-shear cracks and the impact parts eventually *** HTPB propellant forms a breaking hole shaped conical after impact 10 *** mass loss increases by 17 times at maximum,with the working pressure increasing by three ***,the damage value of the breaking hole remaining on the surface increases by 7.8 times while 2.9 times in the depth of the breaking *** breaking efficiency is closely affected by working *** failure modes of HTPB impacted by SCWJ are classified as tensile crack-dominated and tensile-shear crack-dominated damage mechanisms.

关键词： Submerged cavitation water jet Hydroxyl-terminated polybutadiene propellant Breaking characteristics Failure modes

Devolatilization of high viscous fluids with high gravity technology

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Chinese Journal of Chemical Engineering 2024年第7期71卷 249-257页

作者： Jibing Qi youzhi Liu Yandong Liu Taiyuan University Taiyuan 030032China Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering North University of ChinaTaiyuan 030051China

Volatile organic compounds(VOCs)are generally toxic and harmful substances that can cause health and environmental *** removal of VOCs from polymers has become a key *** effective devolatilization to remove VOCs from high viscous fluids such as polymer is necessary and is of great *** this study,the devolatilization effect of a rotating packed bed(RPB)was studied by using polydimethylsiloxane as the viscous fluid and acetone as the *** devolatilization rate and liquid phase volume(KLa)have been *** results indicated that the optimum conditions were the high-gravity factor of 60,liquid flow rate of 10 L·h^(-1),and vacuum degree of 0.077 *** dimensionless correlation of KLa was established,and the deviations between predicted and experimental values were less than±28%.The high-gravity technology will result in lower mass transfer resistance in the devolatilization process,enhance the mass transfer process of acetone,and improve the removal effect of *** work provides a promising path for the removal of volatiles from polymers in combination with high-gravity *** can provide the basis for the application of RPB in viscous fluids.

关键词： High-gravity technology Devolatilization rate High viscous fluid Volatile organic compounds(VOCs)

Mixing planting proportions in a plantation affects functional traits and biomass allocation of Cunninghamia lanceolata and Phoebe bournei seedlings

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Journal of Forestry Research 2022年第6期33卷 1793-1805页

作者： Meiqin Zha youzhi Han Xiangrong Cheng Forestry College Shanxi Agriculture UniversityTaigu 030801People’s Republic of China East China Coastal Forest Ecosystem Long-Term Research Station Institute of Subtropical ForestryChinese Academy of ForestryHangzhou 311400People’s Republic of China

Functional traits of trees are significantly associated with their adaptation strategies and ***,the effects of species composition and mixing proportion on the functional traits of trees grown in mixed plantations have not been studied *** this study,planting experiments(duration about seven months)were used to study variations in functional traits and biomass allocation of C unninghamia lanceolata(Lamb.)Hook and Phoebe bournei(Hemsley)Yang seedlings in five different mixes(0C:4P,1C:3P,1C:1P,3C:1P,and 4C:0P).Total leaf area per seedling increased in each species as its respective proportion in the mixture ***,the specific leaf area decreased for *** under low percent composition,and the specific leaf area for *** differed only marginally among the *** net photosynthetic rates of the two species were higher in the mixed plantings than in their corresponding monocultures,whereas the transpiration rate,stomatal conductance,and instantaneous water use efficiency were not different among the *** average root length and root surface area of *** and *** were higher in the mixed plantings than in their ***,root surface area of *** and both root length and surface area of *** increased significantly in the 1C:3P and 2C:2P mixed ***,stem,root,and total dry mass per seedling for *** decreased with its increasing percent composition in the mixed plantings,while these variables varied less for *** plasticity of biomass allocation was relatively low for both *** biomass per planting was higher in the mixed plantings than in the *** study indicates that species composition and mixing proportion can considerably affect the functional traits of *** and *** increase in productivity in the mixed plantings may be partially attributed to low rates of competition between the two species,an

关键词： Mixing proportion Tree species composition Functional traits Interspecific relationship Intraspecific relationship

The turbulent behavior of novel free triple-impinging jets with large jet spacing by means of particle image velocimetry

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Chinese Journal of Chemical Engineering 2016年第6期24卷 757-766页

作者： Jun Zhang youzhi Liu Ying Luo Shanxi Province Key Laboratory of Higee-oriented Chemical Engineering North University of China

A novel reactor that achieves rapid liquid–liquid mixing via free triple-impinging jets(FTIJs) is developed to improve mixing efficiency at unequal flow rates for liquid–liquid reactions. The flow characteristics of FTIJs were investigated using particle image velocimetry(PIV). The instantaneous and mean velocities data at different Reynolds numbers(Re) were analyzed to provide insights into the velocity distributions in FTIJs. The effect of jet spacing on the stagnation points, instantaneous velocity, mean velocity, profiles of the x- and ycomponents of mean velocity, and turbulent kinetic energy(TKE) distributions of FTIJs were investigated at Re = 4100 with a volumetric flow rate ratio of 0.5. The characteristics of the turbulent flows are similar for all jet spacings tested. Two stagnation points are observed, which are independent of jet spacing and are not located in the center of the flow field. However, velocity and TKE distributions are strongly dependent on the jet *** jet spacing increases the expansion angle and the values of TKE, leading to strong turbulence, improving momentum transfer and mixing efficiency in FTIJs. The present study shows that optimization of the operating parameters is helpful for designing FTIJs.

关键词： Expansion angleFree triple-impinging jetsTurbulent kinetic energyPIV

Oxidation of benzyl alcohols to ketones and aldehydes by O3 process enhanced using high-gravity technology

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Chinese Journal of Chemical Engineering 2020年第3期28卷 808-814页

作者： Wenqiang Gao Lei Du Weizhou Jiao youzhi Liu Shanxi Province Key Laboratory of Higee-Oriented Chemical Engineering North University of ChinaTaiyuan 030051China Department of Chemistry and Chemical Engineering Luliang UniversityLuliang033000China

In this study,a practical process for ozonization of benzyl alcohols to ketones and aldehydes in a rotating packed bed(RPB-O3)reactor has been *** 1-phenylethanol as a model reactant,the performance of RPB-O3 process in different solvents has been compared with the commonly used stirred tank reactor(STR-O3).Ethyl acetate was the optimum solvent for the conversion of 1-phenylenthanol to acetophenone in RPB-O3 process,with 78%yield after 30 *** a parallel STR-O3 experiment,the yield of acetophenone was50%.Other experimental variables,i.e.O3 concentration,reaction time,high-gravity factor and liquid flow rate were also *** highest yield of acetophenone was obtained using O3 concentration of 80 mg·L-1,reaction time of 30 min,high gravity factor of 40 and liquid flow rate of 120 L·*** the optimized reaction conditions,a series of structurally diverse primary and secondary alcohols was oxidized with(19%–92%)*** ozonization mechanism was studied by Electron Paramagnetic Resonance(EPR)spectroscopy,monitoring the radical species formed upon self-decomposition of *** characteristic quadruple peak with the 1:2:2:1 intensity ratio that corresponds to hydroxyl radicals(·OH)was observed in the electron paramagnetic resonance(EPR)spectrum,indicating an indirect oxidation mechanism of alcohols via·OH radical.

关键词： Ozone Benzyl alcohols Aldehydes and ketones High-gravity technology

Expansion Performance and Microstructure of High-performance Concrete using Differently Scaled MgO Agents and Mineral Powder

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Journal of Wuhan University of Technology(Materials Science) 2023年第6期38卷 1335-1347页

作者： TIAN Changjin WANG youzhi QIU Kai YANG Qilin School of Civil Engineering Shandong UniversityJinan 250002China China Construction Infrastructure Co. LtdBeijing 100089China School of Transportation Science and Engineering Harbin Institute of TechnologyHarbin 150090China

To investigate the assumptions proposed in this paper,the evolution law governing the strength and expansion performance of MgO and nano-MgO micro-expansive concrete in the environment of mineral powder was firstly observed in this ***,SEM,XRD,and TG-DSC microscopic tests were conducted to reveal the effects of the active mineral-powder admixture on the hydration degree and expansion performance of MgO and nano-MgO in *** experimental results successfully verified our hypothesis,which indicated that the expansion performance of macro-MgO and nano-MgO was indeed depressed by the addition of active mineral power admixtures,even though the mechanical property of concrete composites was effectively ***,the hydration test also demonstrated the negative interference on the mineral powders,which was induced by the expansion *** is found the amounts of hydrates tend to decrease because the mineral powder ratio reaches and exceeds 40%.Moreover,it is also concluded the effect of expansion agents is governed by the alkalinity cement paste,especially for the *** other words,the expansion performance of nano-MgO will vary more obviously with the hydration process,than *** results of this study provide that effective experimental and theoretical data support the hydration-inhibition mechanism of magnesium expansive agents.

关键词： MgO Nano-MgO mineral powders high-performance concrete expansive agents microstructures

Machining the Integral Impeller and Blisk of Aero-Engines:A Review of Surface Finishing and Strengthening Technologies

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Chinese Journal of Mechanical Engineering 2017年第3期30卷 528-543页

作者： youzhi Fu Hang Gao Xuanping Wang Dongming Guo key laboratory for precision and non-traditional machining technology of ministry of education dalian university of technologyDalian 116024China

The integral impeller and blisk of an aero-engine are high performance parts with complex structure and made of difficult-to-cut materials. The blade surfaces of the integral impeller and blisk are functional surfaces for power transmission, and their surface integrity has signif- icant effects on the aerodynamic efficiency and service life of an aero-engine. Thus, it is indispensable to finish and strengthen the blades before use. This paper presents a comprehensive literature review of studies on finishing and strengthening technologies for the impeller and blisk of aero-engines. The review includes independent and inte- grated finishing and strengthening technologies and dis- cusses advanced rotational abrasive flow machining with back-pressure used for finishing the integral impeller and blisk. A brief assessment of future research problems and directions is also presented.

关键词： Integral impeller and blisk Aero-engine Surface integrity Surface finishing Surface strengthening