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Bilayer Compounded Polytetrafluoroethylene Membrane for Enhanced Oil-Water Emulsion Separation

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Chinese Journal of Polymer Science 2024年第6期42卷 838-850页

作者： yu-liang yang Tai-Ran Zhang Yan-Ting Han Shao-yun Guo Qin-Gong Rong Jia-Bin Shen State Key Laboratory of Polymer Materials Engineering Polymer Research Institute of Sichuan UniversitySichuan Provincial Engineering Laboratory of Plastic/Rubber Complex Processing TechnologyChengdu610065China West China Hospital/West China School of Nursing Sichuan UniversityChengdu610041China Shandong Senrong New Materials Co. Ltd.Zibo256401China

In order to achieve efficient and durable oil-water emulsion separation,the membranes possessing high separation efficiency and mechanical strength attract extensive attention and are in great demand.In present study,a kind of polytetrafluoroethylene(PTFE)-based bilayer membrane was fabricated by electrospinning fibrous PTFE(fPTFE)on an expanded PTFE(ePTFE)substrate.The morphological observation revealed that the fibrous structure of the fPTFE layer could be tailored by controlling the formulation of spinning solution.The addition of appropriate polyoxyethylene(PEO)would make the fibers in the fPTFE layer finer and more uniform.As a result,the compounded membrane exhibited a small pore size of approximately 1.25µm and a substantial porosity nearing 80%.This led to super-hydrophobicity,characterized by a high water contact angle(WCA)of 149.8°,and facilitated rapid oil permeation.The water-in-oil emulsion separation experiment further confirmed that the compounded membrane not only had a high separation efficiency closing 100%,but such an outstanding separation capacity could be largely retained,either through multiple cycles of use or through strong acid(pH=1),strong alkali(pH=12),or high-temperature(100°C)treatment.Additionally,the mechanical behavior of the bilayer membrane was basically contributed by that of each layer in terms of their volume ratio.More significantly,the poor creep resistance of fPTFE layer was suppressed by compounding with ePTFE substrate.Hence,this study has laid the groundwork for a novel approach to create PTFE-based compounded membranes with exceptional overall characteristics,showing promise for applications in the realm of emulsion separation.

关键词： ePTFE Electrospinning membrane Bilayer compounding Emulsion separation

A Stable Open-Shell Conjugated Diradical Polymer with Ultra-High Photothermal Conversion Efficiency for NIR-Ⅱ Photo-Immunotherapy of Metastatic Tumor

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Nano-Micro Letters 2024年第2期16卷 1-14页

作者： Yijian Gao Ying Liu Xiliang Li Hui Wang yuliang yang yu Luo Yingpeng Wan Chun‑sing Lee Shengliang Li Xiao‑Hong Zhang College of Pharmaceutical Sciences Soochow UniversitySuzhou 215123People’s Republic of China Institute of Functional Nano&Soft Materials(FUNSOM) Soochow UniversitySuzhou 215123People’s Republic of China Center of Super‑Diamond and Advanced Films(COSDAF)&Department of Chemistry City University of Hong Kong83 Tat Chee AvenueKowloonHong Kong SARPeople’s Republic of China

Massive efforts have been concentrated on the advance of eminent near-infrared(NIR) photothermal materials(PTMs) in the NIR-Ⅱ window(1000–1700 nm), especially organic PTMs because of their intrinsic biological safety compared with inorganic PTMs. However, so far, only a few NIR-Ⅱresponsive organic PTMs was explored, and their photothermal conversion efficiencies(PCEs) still remain relatively low. Herein, donor–acceptor conjugated diradical polymers with open-shell characteristics are explored for synergistically photothermal immunotherapy of metastatic tumors in the NIR-Ⅱ window. By employing side-chain regulation, the conjugated diradical polymer TTB-2 with obvious NIR-Ⅱ absorption was developed, and its nanoparticles realize a record-breaking PCE of 87.7% upon NIR-Ⅱ light illustration. In vitro and in vivo experiments demonstrate that TTB-2 nanoparticles show good tumor photoablation with navigation of photoacoustic imaging in the NIR-Ⅱ window, without any side-effect. Moreover, by combining with PD-1 antibody,the pulmonary metastasis of breast cancer is high-effectively prevented by the efficient photo-immunity effect. Thus, this study explores superior PTMs for cancer metastasis theranostics in the NIR-Ⅱ window, offering a new horizon in developing radical-characteristic NIR-Ⅱ photothermal materials.

关键词： NIR-Ⅱconjugated polymer Photothermal Radical Nanoparticles Cancer therapy

Multi-Smart Meter Data Encryption Scheme Basedon Distributed Differential Privacy

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Big Data Mining and Analytics 2024年第1期7卷 131-141页

作者： Renwu Yan yang Zheng Ning yu Cen liang School of Electronic Electrical Engineering and PhysicsFujian University of TechnologyFuzhou 350118China Department of Computing Sciences at The College at Brockport State University of New YorkNew YorkNY 14420USA

Under the general trend of the rapid development of smart grids,data security and privacy are facing serious challenges;protecting the privacy data of single users under the premise of obtaining user-aggregated data has attracted widespread attention.In this study,we propose an encryption scheme on the basis of differential privacy for the problem of user privacy leakage when aggregating data from multiple smart meters.First,we use an improved homomorphic encryption method to realize the encryption aggregation of users’data.Second,we propose a double-blind noise addition protocol to generate distributed noise through interaction between users and a cloud platform to prevent semi-honest participants from stealing data by colluding with one another.Finally,the simulation results show that the proposed scheme can encrypt the transmission of multi-intelligent meter data under the premise of satisfying the differential privacy mechanism.Even if an attacker has enough background knowledge,the security of the electricity information of one another can be ensured.

关键词： smart grid homomorphic encryption data aggregation differential privacy cloud computing

Elastic buckling analysis and optimization of thin-walled bamboo-like pipe beam subjected to pure bending

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Chinese Journal of Aeronautics 2024年第3期37卷 133-152页

作者： Yayun yu Dongli MA liang ZHANG Xiaopeng yang Hao GUAN School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China

In this paper,a stiffening design imitating the bamboo node is proposed for weight reduction of the long composite pipe beam subjected to bending load.The distribution of bamboo nodes can efficiently suppress the ovalization of the section,thus significantly improving the bending resistance of the bamboo.Based on this principle,ring stiffeners are proposed to be fixed to the pipe beam,making the long beam equivalent to the combination of a series of short pipes that suffered less section ovalization.A database of the optimal laminate orientations for different normalized lengths is obtained through optimizations,where the discreteness of the ply count is considered.Based on this database,weight optimizations are conducted,and the optimal designs of beams with and without stiffeners are obtained and compared.The comparison results show that the proposed bamboo-like stiffened beam not only regains a near-linear load–displacement relationship,but also reduces the weight by up to 16%under the same buckling load.In addition,it is found that for the pipe beams with radius-to-thickness ratios of more than 18,increasing the radius leads to a decrease in elastic buckling resistance when the weight remains a constant,which is opposite to the design for strength and stiffness.The model and database developed in this paper can provide a reference for weight reduction design and weight estimation for composite pipe beams.

关键词： Composite beam Buckling Thin-walled structure Unmanned aerial vehicles Bamboo

Stabilization and detection of labile reaction intermediates in supramolecular containers

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Chinese Chemical Letters 2024年第6期35卷 47-52页

作者： Rui Wang yang liang Julius Rebek Jr. yang yu Center for Supramolecular Chemistry&Catalysis and Department of Chemistry College of ScienceShanghai UniversityShanghai 200444China Skaggs Institute for Chemical Biology and Department of Chemistry The Scripps Research InstituteLa JollaCA 92037United States

Detection and observation of reactive intermediates is an essential step in investigation of reaction pathways.However,most reactive intermediates are unstable and present at low concentrations;their short lifetimes make them difficult to detect and characterize.Supramolecular containers offer opportunities for the stabilization and characterization of those labile species,through isolation from the media and protection inside the cavity of the host.In this review,we summarize the examples of labile reaction intermediates that are stabilized and characterized with the help of supramolecular containers.The container compounds include carcerands,deep cavitands and amide naphthotubes.We focus on unstable guest species-cyclobutadiene,benzocyclopropenone,o-benzyne,1,2,4,6-cycloheptatetraene,anti-Bredt's olefin,fluorophenoxycarbene,O-acylisoamide,and hemiaminalthat act as intermediates in certain organic reactions.

关键词： Supramolecular containers Reaction intermediates Labile species stabilization Short-lived species detection Supramolecular chemistry

Strip flatness prediction of cold rolling based on ensemble methods

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Journal of Iron and Steel Research(International) 2024年第1期31卷 237-251页

作者： Wu-quan yang Zhi-ting Zhao liang-yu Zhu Xun-yang Gao Li Wang School of Mechanical and Power Engineering Shenyang University of Chemical TechnologyShenyang110142LiaoningChina

Aiming at the problem of insufficient prediction accuracy of strip flatness at the outlet of cold tandem rolling,the prediction performance of strip flatness based on different ensemble methods was studied and a high-precision prediction ensemble model of strip flatness at the outlet was established.Firstly,based on linear regression(LR),K nearest neighbors(KNN),support vector regression,regression trees(RT),and backpropagation neural network(BPN),bagging,boosting,and stacking ensemble methods were used for ensemble experiments.Secondly,three existing ensemble models,i.e.,random forest,extreme random tree(ET)and extreme gradient boosting,were used to conduct experiments and compare the results.The research shows that bagging,boosting,and stacking three ensemble methods have the most significant improvement in the prediction accuracy of the regression trees model,which is increased by 5.28%,6.51%,and 5.32%,respectively.At the same time,the stacking ensemble method improves both the simple model and the complex model,and the improvement effect on the simple base model is the greatest,which is 4.69%higher than that of the base model KNN.Comparing all of the ensemble models,the stacking ensemble model of level-1(ET,AdaBoost-RT,LR,BPN)paired with level-2(LR)was discovered to be the best model(EALB-LR)and can be further studied for industrial applications.

关键词： Tandem cold rolling Flatness prediction Machine learning Ensemble method

Novel concept of nano-additive design:PTFE@silica Janus nanoparticles for water lubrication

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Friction 2024年第2期12卷 258-270页

作者： Yanfei LIU Hailing HE Meng yang Ruize ZHANG Shengtao yu Tiantian yang Wenzhong WANG Fuxin liang School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China Institute of Polymer Science&Engineering Department of Chemical EngineeringTsinghua UniversityBeijing 100084China MOE Key Laboratory of Bioinformatics Center for Plant BiologySchool of Life SciencesTsinghua UniversityBeijing 100084China Tsinghua-Peking Center for Life Sciences Beijing 100084China College of Biological Sciences China Agricultural UniversityBeijing 100193China

Polytetrafluoroethylene(PTFE)has been widely used as a lubrication additive for reducing friction and wear;however,the hydrophobic nature of PTFE restricts its application in eco-friendly water-based lubrication systems.In this study,for the first time,we designed novel PTFE@silica Janus nanoparticles(JNs)to meet the requirement for additives in water-based lubricants,which have excellent dispersion stability in water attributed to the unique amphiphilic structure.By introducing the lubrication of the aqueous dispersion of the JNs with a concentration of 0.5 wt%,the coefficient of friction(COF)and wear volume were reduced by 63.8%and 94.2%,respectively,comparing to those with the lubrication of pure water.Meanwhile,the JNs suspension also exhibits better lubrication and wear-resistance performances comparing to commercial silica and PTFE suspensions.The excellent tribological behaviors of PTFE@silica JNs as nano-additives could be attributed to the synergetic effect of the two components,where the PTFE provided lubrication through the formed tribofilms on the friction pairs,and the rigid silica further enhanced the wear-resistance performance.Most importantly,the unique structure of JNs makes it possible to use PTFE as an additive in water-lubrication systems.Our study shed light on the design and application of novel JNs nanomaterials as additives to meet the requirements of future industrial applications.

关键词： Janus nanoparticles(JNs) polytetrafluoroethylene(PTFE) nano-additives friction lubrication

Failure transition of shear-to-dilation band of rock salt under triaxial stresses

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 56-64页

作者： Jianfeng Liu Xiaosong Qiu Jianxiong yang Chao liang Jingjing Dai yu Bian State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu610065China CNPC Key Laboratory of Oil and Gas Underground Storage Engineering Langfang065007China College of Water Resource and Hydropower Sichuan UniversityChengdu610065China

Great potential of underground gas/energy storage in salt caverns seems to be a promising solution to support renewable energy.In the underground storage method,the operating cycle unfortunately may reach up to daily or even hourly,which generates complicated pressures on the salt cavern.Furthermore,the mechanical behavior of rock salt may change and present distinct failure characteristics under different stress states,which affects the performance of salt cavern during the time period of full service.To reproduce a similar loading condition on the cavern surrounding rock mass,the cyclic triaxial loading/unloading tests are performed on the rock salt to explore the mechanical transition behavior and failure characteristics under different confinement.Experimental results show that the rock salt samples pre-sent a diffused shear failure band with significant bulges at certain locations in low confining pressure conditions(e.g.5 MPa,10 MPa and 15 MPa),which is closely related to crystal misorientation and grain boundary sliding.Under the elevated confinement(e.g.20 MPa,30 MPa and 40 MPa),the dilation band dominates the failure mechanism,where the large-size halite crystals are crushed to be smaller size and new pores are developing.The failure transition mechanism revealed in the paper provides additional insight into the mechanical performance of salt caverns influenced by complicated stress states.

关键词： Rock salt Cyclic mechanical loading Shear band Dilation band Underground gas storage(UGS)

The influence of yttrium and manganese additions on the degradation and biocompatibility of magnesium-zinc-based alloys:In vitro and in vivo studies

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Journal of Magnesium and Alloys 2024年第2期12卷 608-624页

作者： Lei Shi yang Yan Chun-sheng Shao Kun yu Bo Zhang liang-jian Chen Third Xiangya Hospital Central South UniversityChangsha 410013China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China School of Materials Science and Engineering Central South UniversityChangsha 410083China Department of Mechanical Engineering City University of Hong KongHong KongChina

The repair and regeneration of bone defects are highly challenging orthopedic problems.Recently,Mg-based implants have gained popularity due to their unique biodegradation and elastic modulus similar to that of human bone.The aim of our study is to develop a magnesium alloy with a controllable degradation that can closely match bone tissue to help injuries heal in vivo and avoid cytotoxicity caused by a sudden increase in ion concentration.In this study,we prepared and modified Mg-3Zn,Mg-3Zn-1Y,and Mg-2Zn-1Mn by hot extrusion,and used Mg-2.5Y-2.5Nd was as a control.We then investigated the effect of additions of Y and Mn on alloys'properties.Our results show that Mn and Y can improve not only compression strength but also corrosion resistance.The alloy Mg-2Zn-1Mn demonstrated good cytocompatibility in vitro,and for this reason we selected it for implantation in vivo.The degraded Mg-2Zn-1Mn implanted a bone defect area did not cause obvious rejection and inflammatory reaction,and the degradation products left no signs of damage to the heart,liver,kidney,or brain.Furthermore,we find that Mg-2Zn-1Mn can promote an osteoinductive response in vivo and the formation of bone regeneration.

关键词： Magnesium alloy Biodegradation Biocompatibility Bone regeneration Bone defect repair