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Scalable exfoliation for few-layered hexagonal boron nitride nanosheets(BNNSs) by microwave-assisted expansion and liquid nitrogen intercalation

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Chinese Chemical Letters 2020年第7期31卷 1936-1940页

作者： Zhansheng Ma Zan Liu Zhilin Cheng School of Chemistry and Chemical Engineering Yangzhou UniversityYangzhou 225002China

The low cost and facile scalable exfoliation route for two-dimensional hexagonal boron nitride(h-BN)was still indispensable for potential applications.In this work,we presented a convenient and scalable exfoliation for few-layer BNNSs.Taking advantage of the advantages of swift heating of microwave and ultra low temperature vaporization of liquid nitrogen,bulk h-BN was high-efficiently exfoliated into fewlayer BNNSs.The as-exfoliated BNNSs had a 2-6 nm thickness and approximately 7.91%yield,exhibiting scalable,facile and environment-friendly features.Furthermo re,the as-exfoliated BNNSs we re applied as additive in oil for reducing friction of oil.The COF of the BNNSs-based grease reduced by 20.10% compared to grease,and the antiwear performance decreased by 55.8% and 45.1% relative to grease and h-BN-based grease.

关键词： BNNSs Exfoliation Microwave liquid nitrogen Friction

Two-Phase Flow Pressure Drop of liquid nitrogen Boiling in the Straight Section Downstream of U-Bend

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Journal of Shanghai Jiaotong university(Science) 2014年第4期19卷 495-501页

作者：邓冬谢斯卫汪荣顺 School of Mechanical Engineering Shanghai Jiaotong University

The gas-liquid(two-phase) flow pressure drop of liquid nitrogen boiling in the straight section downstream of U-bend is investigated experimentally. The mass flux ranges from 32 to 280 kg/(m2· s). The inlet pressure of U-tube is from 140 to 272 kPa. And the curvature ratio is from 6.67 to 15. The tube wall including the U-bend is heated uniformly and the heat flux ranges from 0 to 22 kW/m2. The tube with higher inlet pressure has higher pressure drop in the downstream section of the bend. The bended degree of the U-bend influences the pressure drop in the downstream straight section of U-bend. A new correlation taking the effect of the secondary flow into account is proposed for the two-phase slip speed ratio. The pressure drop in the straight section downstream of U-bend calculated by the new correlation agrees well with experimental measurements.

关键词： pressure drop downstream of U-bend secondary flow liquid nitrogen

Experimental Study of Motion of nitrogen Taylor Bubbles and liquid Slugs in Inclined Tubes

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Chinese Journal of Aeronautics 2009年第4期22卷 349-354页

作者： Zhang Hua,Wang Shuhua,Wang Jing Institute of Engineering Thermo-physics,Shanghai Jiao Tong University,Shanghai 200240,China Institute of Engineering Thermo-physics Shanghai Jiao Tong University Shanghai 200240 China

This article studies rising velocity of Taylor bubbles and liquid slugs in liquid nitrogen at different axial positions in upward inclined tubes by means of a high speed motion analyzer. The bottom-closed tubes in the experiments are 1.0 m long with an inner diameter of 0.014 m or 0.018 m. The tube inclines upward from 0~ to 50~ with respect to the normal. Statistical method is used to analyze the data of the Taylor bubble and the liquid slug velocity. Reflecting the effects of the inclination angle on the rising velocity of Taylor bubbles and liquid slugs, the experimental results indicate the similar trend the Taylor bubble velocity and the liquid slug velocity have： it increases first, and then decreases with the increase of the inclination angle. Moreover, with the increase of the inclination angle, the liquid slug velocity becomes greater than Taylor bubble velocity.

关键词： cryogenic two-phase flow rising velocity high speed motion analyzer liquid nitrogen Taylor bubble liquid slug inclined tube

EXPERIMENTAL STUDY OF INFLUENCE OF liquid nitrogen PRESERVATION ON ANTIGENICITY OF HUMAN HOMOGRAFT AORTIC VALVE

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Journal of Pharmaceutical Analysis 1999年第2期13卷 157-161页

作者： Fan Zhaohui,Huang Qingheng,Zhao Jian, Geng Xigang,Liu Jianlin,Ren Huping Department of Cardiovascular Surgery, First Affiliated Hospital of Xi′an Medical University, Xi′an 710061 Department of Cardiovascular Surgery First Affiliated Hospital Xi'an Medical University Xi'an 710061 China

To illustrate the effect of liquid nitrogen preservation on antigenicity of human homograft aortic valve (HAV), human aortic valve tissue were cocultured together with peripheral blood mononuclear cells (PBMCs). Following detections were done to show the difference of antigenicity of HAV indirectly at different period after being preserved in liquid nitrogen: ① 3H TdR incorporation (cpm) was observed after tissue cell cocultured and stimulation index (SI) was calculated;② Density of IL 2 in medium was measured by MTT means. The results indicated that antigenicity of fresh HAV was the strongest; with the prolong of being preserved, antigenicity decreased gradually. It decreased significantly within first 48 h preserved at 4℃, then decreased significantly after preserved in liquid nitrogen for 24 h. 2 weeks later, antigenicity decreased to the lowest level.

关键词： liquid nitrogen homograft aortic valve (HAV) antigenicity stimulation index(SI)

Experimental study on the explosive boiling in saturated liquid nitrogen

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Progress in Natural Science:Materials International 2005年第1期 62-66页

作者： DONG Zhaoyi, HUAI Xiulan* and LIU Dengying(Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100080, China)

Studies on the heat-transfer characteristics of liquid nitrogen (LN 2) have received increasing attention. When there is a transient high heatflux input to the LN 2, explosive boiling may take place. In this paper, using the high-power short-duration pulsed laser heating method and the high-speed photography technology, the experimental result of explosive boiling in saturated LN 2 is illustrated; and the two exclusive characteristics of explosive boiling in LN 2: changeover time and the relative long-time adherence of the bubble cluster to the surface, are investigated.

关键词： liquid nitrogen explosive boiling process visualization.

Synthesis of reusable NH_(2)-MIL-125(Ti)@polymer monolith as efficient adsorbents for dyes wastewater remediation

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Green Chemical Engineering 2023年第4期4卷 439-447页

作者： Peng Yao Yang Liu Xue Tang Shuxiang Lu Zhen Li Yue Yao College of Chemical Engineering and Materials Science Tianjin University of Science and TechnologyTianjin300457China

NH_(2)-MIL-125(Ti)is a Ti-MOFs(MOFs:metal-organic frameworks)with high adsorption properties and is therefore widely used for wastewater purification.However,the powdered MOF material suffers from the disadvantages of being difficult to separate and being potentially wasted due to easy agglomeration,which limits its application in practical applications.Here,a mesoporous Ti-MOF/polymer(PEG,PVA,and PAM)monolithic material was prepared by freeze casting in liquid nitrogen(-196℃)as an adsorbent for wastewater remediation.The composites could be easily picked up with tweezers and used for recovery tests.Characterization results such as XRD,BET,FT-IR,and SEM proved the successful synthesis of Ti-MOF/polymer.Adsorption tests using 100 mg/L methylene blue(MB)simulated wastewater showed that the Ti-MOF/PEG monolithic material had the best adsorption capacity.The order of adsorption was Ti-MOF@PEG10(747.4 mg/g)>Ti-MOF@PVA10(687.4 mg/g)>Ti-MOF@PAM10(633.7 mg/g)>NH_(2)-MIL-125(Ti)(571.4 mg/g).The effects of polymer dosage,different pollutants(methylene blue,methyl orange,indigo,actual textile wastewater),pH,anions,and cations on the adsorption effect of Ti-MOF/polymer were also investigated.It was demonstrated that all the above pollutants were well adsorbed by this Ti-MOF/polymer in the pH range 3-9.The adsorption isotherms and kinetic data are fully consistent with the Langmuir and pseudo-secondary models.This suggests that the adsorption between the pollutant and the adsorbent is a chemical interaction.Thermodynamic studies indicate that the adsorption process is exothermic and spontaneous.This work provides the potential methods to fabricate Ti-MOF/polymer monolith to avoid the pollution from powdery adsorbents that could be practical applications.

关键词： Adsorption NH_(2)-MIL-125(Ti) Freeze-casting method Methylene blue Polymers liquid nitrogen

Delamination of Birnessite MnO_(2) into Nanosheets as Anode Materials for Lithium Ion Batteries

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Journal of Harbin Institute of Technology(New Series) 2021年第4期28卷 77-83页

作者： Ao Xia Jue Yi Wanru Yu Xin Yang Chenpeng Zhao School of Materials Science and Engineering Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic MaterialsShaanxi University of Science&TechnologyXi’an 710021China Shaanxi Rainbow New Material Co. Ltd.Xianyang 712000ShaanxiChina

The delamination of birnessite MnO_(2) into nanosheets by freezing and thawing method was reported here.The proton⁃type birnessite manganese oxide(H⁃birnessite)was added to tetramethylammonium hydroxide(TMAOH)solution in a polypropylene tube which was then sealed.Fifty cycles consisting of fast freezing(in liquid nitrogen for 30 s)and thawing(in 70℃ water for 30 min)were operated.The as⁃prepared slurry was characterized by X⁃ray diffraction(XRD)and transmission electron microscope(TEM).The XRD result showed the layered structural H⁃birnessite was delaminated.The TEM result revealed the product had a nanosheet⁃like morphology.Employed as an anode material for lithium⁃ion batteries,MnO_(2) nanosheets as⁃prepared delivered a specific charging capacity of 1040.6 mAh/g after 100 cycles at 100 mA/g.

关键词： birnessite MnO_(2) nanosheets lithium⁃ion batteries specific capacity liquid nitrogen

Development and test in grid of 630 kVA three-phase high temperature superconducting transformer

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Frontiers of Electrical and Electronic Engineering in China 2009年第1期4卷 104-113页

作者： Yinshun WANG Xiang ZHAO Junjie HAN Huidong LI Yin GUAN Qing BAO Xi XU Shaotao DAI Naihao SONG Fengyuan ZHANG Liangzhen LIN Liye XIAO Institute of Electrical Engineering Chinese Academy of SciencesBeijing 100080China Technical Center of Tebian Electric Apparatus Stock Co. LtdChangji 831100China Beijing Key Laboratory of High Voltage and EMC School of Electrical and Electronic EngineeringNorth China Electric Power UniversityBeijing 102206China

A 630-kVA 10.5 kV/0.4 kV three-phase high temperature superconducting(HTS)power transformer was successfully developed and tested in a live grid.The windings were wound by hermetic stainless steelreinforced multi-filamentary Bi2223/Ag tapes.The structures of primary windings are solenoid with insulation and cooling path among layers,and those of secondary windings consist of double-pancakes connected in parallel.Toroidal cryostat is made from electrical insulating glass fiber reinforced plastics(GFRP)materials with room temperature bore for commercial amorphous alloy core with five limbs.Windings are laid in the toroidal cryostat so that the amorphous core operates at room temperature.An insulation technology of double-half wrapping up the Bi2223/Ag tape with Kapton film is used by a winding machine developed by the authors.Fundamental characteristics of the transformer are obtained by standard short-circuit and no-load tests,and it is shown that the transformer meets operating requirements in a live grid.

关键词： high temperature superconducting(HTS)transformer Bi2223/Ag tape amorphous alloy windings liquid nitrogen

Cryopreservation of Cyrtopodium hatschbachii Pabst (Orchidaceae) immature seeds by encapsulation-dehydration

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BIOCELL 2012年第1期36卷 31-36页

作者： MAURO RODRIGO SURENCISKI EDUARDO ALBERTO FLACHSLAND GRACIELA TERADA LUIS AMADO MROGINSKI AND HEBE YOLANDA REY Instituto de Botánica del Nordeste(IBONE) CONICET–UNNEFacultad de Ciencias Agrarias(UNNE)C.C.209(3400)CorrientesArgentina

The aim of the present study was to investigate the efficiency of the encapsulation-dehydration technique for cryopreservation of Cyrtopodium hastchbachii Pabst seeds.Immature seeds of this species were cryopreserved by an encapsulation-dehydration technique.Seeds of five immature pods,120 days after pollination,were encapsulated in 3%calcium alginate matrix and pretreated in liquid medium supplemented with 0.08 M sucrose(24 h),0.15 M sucrose(24 h),0.25 M sucrose(48 h),0.5 M sucrose(24 h)and 0.75 M sucrose(24 h)in shaker at 60 rpm.Alginate beads were dehydrated 5 h in silicagel and immersed in liquid nitrogen for 12 h.Cryopreserved beads were thawed at 30℃ for 1 min,rehydrated using the same liquid mediums[0.75 M sucrose(24 h),0.5 M sucrose(24 h),0.25 M sucrose(48 h)and 0.15 M sucrose(24 h)]and cultivated in half strength Murashige&Skoog medium(1962)with the addition of 2 g/L activated charcoal.Sixty four percent of seeds survived and developed into acclimatized plants after being cryopreserved.In this work,the encapsulation-dehydration technique was employed for first time in Cyrtopodium hatschbachii.

关键词： cryoconservation liquid nitrogen calcium alginate activated charcoal sucrose