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Organic Compounds Possessing the Plastic Crystalline Phase: Calculation of Their Fusion Enthalpies
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作者 Mikhail Yu. Gorbachev Natalia N. Gorinchoy 《International Journal of Organic Chemistry》 2024年第3期93-106,共14页
For the first time, for different organic and inorganic compounds possessing the plastic crystalline phase, a new semiempirical equation describing dependence of their fusion enthalpies on such physico-chemical quanti... For the first time, for different organic and inorganic compounds possessing the plastic crystalline phase, a new semiempirical equation describing dependence of their fusion enthalpies on such physico-chemical quantities as normal melting temperature, surface tension, molar volume and critical molar volume is received on the base of the principle of corresponding states and the energy equipartition theorem. Moreover, the proposed equation allows one to take into account the particularities of one-particle molecular rotation in the plastic crystalline phase. 展开更多
关键词 Fusion Enthalpies Calculation Organic Compounds Inorganic Compounds Plastic crystalline phases
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Direct observation of shock-induced phase transformation in polycrystalline iron via in situ x-ray diffraction
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作者 Fan Zhang Jia-Qin Dong +11 位作者 Zhi-Yong Xie Zhi-Yu He Hua Shu Rui-Rong Wang Jun Xiong Guo Jia Zhi-Heng Fang Wei Wang Da-Wu Xiao An-Le Lei Jie Chen Xiu-Guang Huang 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第10期337-342,共6页
Phase transition of polycrystalline iron compressed along the Hugoniot is studied by combining laser-driven shock with in situ x-ray diffraction technique.It is suggested that polycrystalline iron changes from an init... Phase transition of polycrystalline iron compressed along the Hugoniot is studied by combining laser-driven shock with in situ x-ray diffraction technique.It is suggested that polycrystalline iron changes from an initial body-centered cubic structure to a hexagonal close-packed structure with increasing pressure(i.e.,a phase transition fromαtoε).The relationship between density and pressure for polycrystalline iron obtained from the present experiments is found to be in good agreement with the gas-gun Hugoniot data.Our results show that experiments with samples at lower temperatures under static loading,such as in a diamond anvil cell,lead to higher densities measured than those found under dynamic loading.This means that extrapolating results of static experiments may not predict the dynamic responses of materials accurately.In addition,neither the face-centered cubic structure seen in previous molecular-dynamics simulations or twophase coexistence are found within our experimental pressure range. 展开更多
关键词 in situ x-ray diffraction phase transition polycrystalline iron
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Constructing long-cycling crystalline C_(3)N_(4)-based carbonaceous anodes for sodium-ion battery via N configuration control 被引量:1
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作者 Ying Wang Hongguan Li +5 位作者 Shuanlong Di Boyin Zhai Ping Niu Antonios Kelarakis Shulan Wang Li Li 《Carbon Energy》 SCIE EI CAS CSCD 2024年第1期159-171,共13页
Carbon nitrides with two-dimensional layered structures and high theoretical capacities are attractive as anode materials for sodium-ion batteries while their low crystallinity and insufficient structural stability st... Carbon nitrides with two-dimensional layered structures and high theoretical capacities are attractive as anode materials for sodium-ion batteries while their low crystallinity and insufficient structural stability strongly restrict their practical applications.Coupling carbon nitrides with conductive carbon may relieve these issues.However,little is known about the influence of nitrogen(N)configurations on the interactions between carbon and C_(3)N_(4),which is fundamentally critical for guiding the precise design of advanced C_(3)N_(4)-related electrodes.Herein,highly crystalline C_(3)N_(4)(poly(triazine imide),PTI)based all-carbon composites were developed by molten salt strategy.More importantly,the vital role of pyrrolic-N for enhancing charge transfer and boosting Na+storage of C_(3)N_(4)-based composites,which was confirmed by both theoretical and experimental evidence,was spot-highlighted for the first time.By elaborately controlling the salt composition,the composite with high pyrrolic-N and minimized graphitic-N content was obtained.Profiting from the formation of highly crystalline PTI and electrochemically favorable pyrrolic-N configurations,the composite delivered an unusual reverse growth and record-level cycling stability even after 5000 cycles along with high reversible capacity and outstanding full-cell capacity retention.This work broadens the energy storage applications of C_(3)N_(4) and provides new prospects for the design of advanced all-carbon electrodes. 展开更多
关键词 ANODE highly crystalline C_(3)N_(4) N configuration sodium-ion batteries ultra-long cyclic stability
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Biodegradation of Crystalline Chitin:A Review of Recent Advancement,Challenges,and Future Study Directions
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作者 SONG Jianlin SU Haipeng +1 位作者 SUN Jianan MAO Xiangzhao 《Journal of Ocean University of China》 SCIE CAS CSCD 2024年第5期1319-1328,共10页
Chitin is the second most abundant renewable polysaccharide on Earth.The degradation of chitin into soluble and bioactive N-acetyl chitooligosaccharides(NCOSs)and N-acetyl-D-glucosamine(GlcNAc)has emerged as a pivotal... Chitin is the second most abundant renewable polysaccharide on Earth.The degradation of chitin into soluble and bioactive N-acetyl chitooligosaccharides(NCOSs)and N-acetyl-D-glucosamine(GlcNAc)has emerged as a pivotal step in the efficient and sustainable utilization of chitin resources.However,because of its dense structure,high crystallinity,and poor solubility,chitin typically needs pretreatment via chemical,physical,and other methods before enzymatic conversion to enhance the accessibility between substrates and enzyme molecules.Consequently,there has been considerable interest in exploring the direct biological degradation of crystalline chitin as a cost-effective and environment-friendly technology.This review endeavors to present several biological methods for the direct degradation of chitin.We primarily focused on the importance of chitinase containing chitin-binding domain(CBD).Additionally,various modification strategies for increasing the degradation efficiency of crystalline chitin were introduced.Subsequently,the review systematically elucidated critical components of multi-enzyme catalytic systems,highlighting their potential for chitin degradation.Furthermore,the application of microorganisms in the degradation of crystalline chitin was also discussed.The insights in this review contribute to the explorations and investigations of enzymatic and microbial approaches for the direct degradation of crystalline chitin,thereby fostering advancements in biomass conversion. 展开更多
关键词 crystalline chitin CHITINASE biological degradation engineering MICROORGANISMS
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Synthesis of crystalline g-C_(3)N_(4) with rock/molten salts for efficient photocatalysis and piezocatalysis
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作者 Tingting Xu Jung Hur +4 位作者 Ping Niu Shulan Wang Sangwook Lee Sang-Eun Chun Li Li 《Green Energy & Environment》 SCIE EI CAS CSCD 2024年第5期890-898,共9页
Graphitic carbon nitride(g-C_(3)N_(4))is emerging as a promising visible-light photocatalyst while the low crystallinity with sluggish charge separation/migration dynamics significantly restricts its practical applicat... Graphitic carbon nitride(g-C_(3)N_(4))is emerging as a promising visible-light photocatalyst while the low crystallinity with sluggish charge separation/migration dynamics significantly restricts its practical applications.Currently,synthesizing highly crystalline g-C_(3)N_(4) with sufficient surface activities still remains challenging.Herein,different from using alkali molten salts which is commonly reported,we propose an approach for synthesis of highly crystalline g-C_(3)N_(4) with FeCl3/KCl rock/molten mixed salts.The rock salt can serve as the structure-directing template while molten salt provides the required liquid medium for re-condensation.Intriguingly,the synthesized photocatalyst showed further enhanced crystallinity and improved surface area along with high p/p*excitation compared with crystalline C_(3)N_(4) prepared from conventional molten-salt methods.These catalytically advantageous features lead to its superior photocatalytic and piezocatalytic activities with a high reactivity for overall water splitting that is not commonly reported for C_(3)N_(4).This work provides an effective strategy for structural optimization of organic semiconductor based materials and may inspire new ideas for the design of advanced photocatalysts. 展开更多
关键词 High crystallinity Carbon nitride PHOTOCATALYSIS Piezocatalysis Overall water splitting
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Three-dimensional topological crystalline insulator without spin-orbit coupling in nonsymmorphic photonic metacrystal
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作者 Zhide Yu Lingbo Xia 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第10期282-286,共5页
By including certain point group symmetry in the classification of band topology,Fu proposed a class of threedimensionaltopological crystalline insulators(TCIs)without spin-orbit coupling in 2011.In Fu’s model,surfac... By including certain point group symmetry in the classification of band topology,Fu proposed a class of threedimensionaltopological crystalline insulators(TCIs)without spin-orbit coupling in 2011.In Fu’s model,surface states(ifpresent)doubly degenerate atГandM when time-reversal and C_(4) symmetries are preserved.The analogs of Fu’s modelwith surface states quadratically degenerate atM are widely studied,while surface states with quadratic degeneracy atГare rarely reported.In this study,we propose a three-dimensional TCI without spin-orbit coupling in a judiciously designednonsymmorphic photonic metacrystal.The surface states of photonic TCIs exhibit quadratic band degeneracy in the(001)surface Brillouin zone(BZ)center(Гpoint).The gapless surface states and their quadratic dispersion are protected by C4and time-reversal symmetries,which correspond to the nontrivial band topology characterized by Z_(2)topological invariant.Moreover,the surface states along lines fromГto the(001)surface BZ boundary exhibit zigzag feature,which is interpretedfrom symmetry perspective by building composite operators constructed by the product of glide symmetries with timereversalsymmetry.The metacrystal array surrounded with air possesses high order hinge states with electric fields highlylocalized at the hinge that may apply to optical sensors.The gapless surface states and hinge states reside in a cleanfrequency bandgap.The topological surface states emerge at the boundary of the metacrystal and perfect electric conductor(PEC),which provide a pathway for topologically manipulating light propagation in photonic devices. 展开更多
关键词 topological crystalline insulator nonsymmorphic photonic metacrystal
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Effect of high-energy Ne ions irradiation on mechanical properties difference between Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5)metallic glass and crystalline W
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作者 李娜 张立松 +3 位作者 张小楠 宫丽悦 羌建兵 梅显秀 《Plasma Science and Technology》 SCIE EI CAS CSCD 2024年第6期14-21,共8页
In this paper,high-energy Ne ions were used to irradiate Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) metallic glass(MG)and crystalline W to investigate their difference in mechanical response after irradiation.The results showed t... In this paper,high-energy Ne ions were used to irradiate Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) metallic glass(MG)and crystalline W to investigate their difference in mechanical response after irradiation.The results showed that with the irradiation dose increased,the tensile micro-strain increased,nano-hardness increased from 7.11 GPa to 7.90 GPa and 8.62 GPa,Young’s modulus increased,and H3/E2 increased which indicating that the plastic deformability decreased in crystalline W.Under the same irradiation conditions,the Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG still maintained the amorphous structure and became more disordered despite the longer range and stronger displacement damage of Ne ions in Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG than in crystalline W.Unlike the irradiation hardening and embrittlement behavior of crystalline W,Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG showed the gradual decrease in hardness from 6.02 GPa to 5.89 GPa and 5.50 GPa,the decrease in modulus and the increase in plastic deformability with the increasing dose.Possibly,the irradiation softening and toughening phenomenon of Zr_(63.5)Cu_(23)Al_(9)Fe_(4.5) MG could provide new ideas for the design of nuclear materials. 展开更多
关键词 heavy ions irradiation displacement damage metallic glass crystalline W mechanical property
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Shock-induced energy localization and reaction growth considering chemical-inclusions effects for crystalline explosives
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作者 Ruqin Liu Yanqing Wu +3 位作者 Xinjie Wang Fenglei Huang Xiaona Huang Yushi Wen 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第3期278-294,共17页
Chemical inclusions significantly alter shock responses of crystalline explosives in macroscale gap experiments but their microscale dynamics origin remains unclear.Herein shock-induced energy localization,overall phy... Chemical inclusions significantly alter shock responses of crystalline explosives in macroscale gap experiments but their microscale dynamics origin remains unclear.Herein shock-induced energy localization,overall physical responses,and reactions in a-1,3,5-trinitro-1,3,5-triazinane(a-RDX)crystal entrained various chemical inclusions were investigated by the multi-scale shock technique implemented in the reactive molecular dynamics method.Results indicated that energy localization and shock reaction were affected by the intrinsic factors within chemical inclusions,i.e.,phase states,chemical compositions,and concentrations.The atomic origin of chemical-inclusions effects on energy localization is dependent on the dynamics mechanism of interfacial molecules with free space volume,which includes homogeneous intermolecular compression,interfacial impact and shear,and void collapse and jet.As introducing various chemical inclusions,the initiation of those dynamics mechanisms triggers diverse decay rates of bulk RDX molecules and hereby impacts on growth speeds of final reactions.Adding chemical inclusions can reduce the effectiveness of the void during the shock impacting.Under the shockwave velocity of 9 km/s,the parent RDX decay rate in RDX entrained amorphous carbon decreases the most and is about one fourth of that in RDX with a vacuum void,and solid HMX and TATB inclusions are more reactive than amorphous carbon but less reactive than dry air or acetone inclusions.The lessdense shocking system denotes the greater increases in local temperature and stress,the faster energy liberation,and the earlier final reaction into equilibrium,revealing more pronounced responses to the present intense shockwave.The quantitative models associated with the relative system density(RD_(sys))were proposed for indicating energy-localization mechanisms and evaluating initiation safety in the shocked crystalline explosive.RD_(sys)is defined by the density ratio of defective RDX to perfect crystal after dynamics relaxation and reveals the global density characteristic in shocked systems filled with chemical inclusions.When RD_(sys)is below 0.9,local hydrodynamic jet initiated by void collapse dominates upon energy localization instead of interfacial impact.This study sheds light on novel insights for understanding the shock chemistry and physical-based atomic origin in crystalline explosives considering chemical-inclusions effects. 展开更多
关键词 Shock responses Energy localization crystalline explosives Chemical inclusions Reactive molecular dynamics
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Isolation of Microcrystalline Cellulose from Wood and Fabrication of Polylactic Acid(PLA)Based Green Biocomposites
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作者 Selwin Maria Sekar Rajini Nagarajan +5 位作者 Ponsuriyaprakash Selvakumar Ismail Sikiru Oluwarotimi Kumar Krishnan Faruq Mohammad Mohammed Rafi Shaik Nadir Ayrilmis 《Journal of Renewable Materials》 EI CAS 2024年第8期1455-1474,共20页
An innovative microcrystalline cellulose(MCC)natural fibre powder-reinforced PLA biocomposite was investigated using the hand lay-up technique.The polymer matrix composite(PMC)samples were prepared by varying the weig... An innovative microcrystalline cellulose(MCC)natural fibre powder-reinforced PLA biocomposite was investigated using the hand lay-up technique.The polymer matrix composite(PMC)samples were prepared by varying the weight percentages(wt.%)of both PLA matrix and MCC reinforcement:pure PLA/100:0,90:10,80:20,70:30,60:40 and 50:50 wt.%,respectively.From the results obtained,MCC powder,with its impressive aspect ratio,proved to be an ideal reinforcement for the PLA,exhibiting exceptional mechanical properties.It was evident that the 80:20 wt.%biocomposite sample exhibited the maximum improvement in the tensile,flexural,notched impact,compressive strength and hardness by 28.85%,20.00%,91.66%,21.53%and 35.82%,respectively compared to the pure PLA sample.Similarly,during the thermogravimetric analysis(TGA),the same 80:20 wt.%biocomposite sample showed a minimum weight loss of 20%at 400℃,among others.The morphological study using Field Emission Scanning Electron Microscopy(FE-SEM)revealed that the uniform distribution of cellulose reinforcement in the PLA matrix actively improved the mechanical properties of the biocomposites,especially the optimal 80:20 wt.%sample.Importantly,it was evident that the optimal PLA/cellulose biocomposite sample could be a suitable and alternative sustainable,environmentally friendly and biodegradable material for semi/structural applications,replacing synthetic and traditional components. 展开更多
关键词 Polylactic acid micro crystalline cellulose BIOCOMPOSITE CHARACTERIZATIONS FESEM environmental pollution
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Strength criterion for crystalline rocks considering grain size effect and tensile-compressive strength ratio
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作者 ZHANG Cheng-han JI Hong-guang +3 位作者 JIANG Peng YOU Shuang GENG Qian-cheng JIAO Chen-jiang 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2365-2378,共14页
The macroscopic mechanical properties of rocks are significantly influenced by their microstructure.As a material bonded by mineral grains,the grain morphology of crystalline rock is the primary factor influencing the... The macroscopic mechanical properties of rocks are significantly influenced by their microstructure.As a material bonded by mineral grains,the grain morphology of crystalline rock is the primary factor influencing the strength.However,most strength criteria neglect the strength variations caused by different grain characteristics in rocks.Furthermore,the traditional linear criteria tend to overestimate tensile strength and exhibit apex singularity.To address these shortcomings,a piecewise strength criterion that considers the grain size effect has been proposed.A part of an ellipse was employed to construct the envelope of the tensive-shear region on the meridian plane,to accurately reproduce the low tensile-compressive strength ratio.Based on the analysis of experimental data,both linear and exponential modification functions that account for grain size effects were integrated into the proposed criterion.The corresponding finite element algorithm has been implemented.The accuracy and applicability of the proposed criterion were validated by comparing with the experimental data. 展开更多
关键词 crystalline rock grain size effect strength criterion tensile-compressive strength ratio finite element algorithm
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Laser-Constructing 3D Copper Current Collector with Crystalline Orientation Selectivity for Stable Lithium Metal Batteries
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作者 Hui Li Gang Wang +3 位作者 Jin Hu Jun Li Jiaxu Huang Shaolin Xu 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第6期129-139,共11页
The practical application of lithium(Li)metal anodes in high-capacity batteries is impeded by the formation of hazardous Li dendrites.To address this challenge,this research presents a novel methodology that combines ... The practical application of lithium(Li)metal anodes in high-capacity batteries is impeded by the formation of hazardous Li dendrites.To address this challenge,this research presents a novel methodology that combines laser ablation and heat treatment to precisely induce controlled grain growth within laser-structured grooves on copper(Cu)current collectors.Specifically,this approach enhances the prevalence of Cu(100)facets within the grooves,effectively lowering the overpotential for Li nucleation and promoting preferential Li deposition.Unlike approaches that modify the entire surface of collectors,our work focuses on selectively enhancing lithiophilicity within the grooves to mitigate the formation of Li dendrites and exhibit exceptional performance metrics.The half-cell with these collectors maintains a remarkable Coulombic efficiency of 97.42%over 350 cycles at 1 mA cm^(−2).The symmetric cell can cycle stably for 1600 h at 0.5 mA cm^(−2).Furthermore,when integrated with LiFePO4 cathodes,the full-cell configuration demonstrates outstanding capacity retention of 92.39%after 400 cycles at a 1C discharge rate.This study introduces a novel technique for fabricating selective lithiophilic three-dimensional(3D)Cu current collectors,thereby enhancing the performance of Li metal batteries.The insights gained from this approach hold promise for enhancing the performance of all laser-processed 3D Cu current collectors by enabling precise lithiophilic modifications within complex structures. 展开更多
关键词 copper current collector heat treatment laser processing lithium metal battery selective crystalline orientation
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Influence of substituting B_(2)O_(3) with Li_(2)O on the viscosity,structure and crystalline phase of low-reactivity mold flux
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作者 Rongzhen Mo Xubin Zhang +2 位作者 Ying Ren Junjie Hu Lifeng Zhang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2023年第7期1320-1328,共9页
The low-reactivity mold flux with low SiO_(2)content is considered suitable for the continuous casting of high-aluminum steel since it can significantly reduce the reaction between Al in steel and SiO_(2)in mold flux.... The low-reactivity mold flux with low SiO_(2)content is considered suitable for the continuous casting of high-aluminum steel since it can significantly reduce the reaction between Al in steel and SiO_(2)in mold flux.However,the traditional low-reactivity mold flux still presents some problems such as high viscosity and strong crystallization tendency.In this study,the co-addition of Li_(2)O and B_(2)O_(3)in CaO–Al_(2)O_(3)–10wt%Si O_(2)based low-reactivity mold flux was proposed to improve properties of mold flux for high-aluminum steel,and the effect of Li_(2)O replacing B_(2)O_(3)on properties of mold flux was investigated.The viscosity of the mold flux with 2wt%Li_(2)O and 6wt%B_(2)O_(3)reached a minimum value of 0.07 Pa·s.The break temperature and melting point showed a similar trend with the viscosity.Besides,the melt structure and precipitation of the crystalline phase were studied using Raman and X-ray diffraction spectra to better understand the evolution of viscosity.It demonstrated that with increasing Li_(2)O content in the mold flux from 0 to 6 wt%,the degree of polymerization of aluminate and the aluminosilicate network structure increased because of increasing Li+released by Li_(2)O,indicating the added Li_(2)O was preferentially associated with Al^(3+)as a charge compensator.The precipitation of LiAlO_(2)crystalline phase gradually increased with the replacement of B_(2)O_(3)by Li_(2)O.Therefore,Li_(2)O content should be controlled below 2wt%to avoid LiAlO_(2)precipitation,which was harmful to the continuous casting of highaluminum steels. 展开更多
关键词 low-reactivity mold flux VISCOSITY STRUCTURE crystalline phase
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Preparation and Performance Study of Cementitious Capillary Crystalline Waterproof Materials
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作者 Hui Li Yu Liu Gaoshang Zhang 《Journal of Architectural Research and Development》 2024年第3期42-52,共11页
Cementitious capillary crystalline waterproof materials(CCCW for short)offer durability and excellent waterproofing properties,making them a popular option for building waterproofing.Some scholars have studied the pro... Cementitious capillary crystalline waterproof materials(CCCW for short)offer durability and excellent waterproofing properties,making them a popular option for building waterproofing.Some scholars have studied the proportioning of such materials.However,these studies lack the relationship between the impermeability pressure of mortar and the components,and the mechanism of action is somewhat debatable.Therefore,we adopted a two-step method in our experiments.Firstly,we screened out the components that significantly impact impermeability from a variety of active components by orthogonal test.We then optimized the design of the active group ratio using the simplex lattice method.Lastly,we conducted a performance test of the optimal ratio and explored the waterproofing mechanism of homemade CCCW. 展开更多
关键词 Cementitious penetration crystalline waterproof material IMPERMEABILITY Mechanism analysis Optimization design
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Phase evolution of plasma sprayed Al_2O_3-13%TiO_2 coatings derived from nanocrystalline powders 被引量:2
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作者 路学成 阎殿然 +3 位作者 杨勇 董艳春 何继宁 张建新 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第10期2951-2956,共6页
Commercial nanosized alumina and titania particles were selected as raw materials to prepare the blended slurry with composition of A1203-13%TiO2 (mass fraction), which were reconstituted into micrometer-sized granu... Commercial nanosized alumina and titania particles were selected as raw materials to prepare the blended slurry with composition of A1203-13%TiO2 (mass fraction), which were reconstituted into micrometer-sized granules by spray drying, subsequently sintering at different temperatures to form nanostructured feedstock for thermal spraying, and then A1203-13%TiO2 nanocoatings were deposited by plasma spraying. The evolution of morphology, microstructure, and phase transformation of the agglomerated powder and as-sprayed coatings were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that A1203 retains the same a phase as the raw material during sintering, while TiO2 changes from anatase to futile. During plasma spraying, some a-A1203 phases solidify to form metastable y-A1203, and the volume fraction of a-A1203 decreases as CPSP increases. However, peaks of the TiO2 phase are not observed from the as-sprayed coatings except for the coatings sprayed at the lower CPSP. As the CPSP increases, nanostructured TiO2 is dissolved easily in y-A1203 or z-A1203'TiO2 phase. After heat treatment, y-A1203 in the coatings transforms to a-A1203, and rutile is precipitated. 展开更多
关键词 A1203-13%TiO2 nanocrystalline powder NANOCOATINGS phase evolution
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基于CTA颅内动脉瘤形态联合PHASES评分对破裂出血预测研究
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作者 王金泉 黄吉淮 谢颖 《影像研究与医学应用》 2024年第4期31-34,共4页
目的:分析头颈部计算机断层扫描血管成像(CTA)联合PHASES评分对颅内动脉瘤(IA)破裂出血的预测价值。方法:回顾性分析2021年10月—2023年9月东莞市长安医院诊治的IA患者临床资料,根据IA破裂出血与否分为IA破裂组(n=46)和IA未破裂组(n=44)... 目的:分析头颈部计算机断层扫描血管成像(CTA)联合PHASES评分对颅内动脉瘤(IA)破裂出血的预测价值。方法:回顾性分析2021年10月—2023年9月东莞市长安医院诊治的IA患者临床资料,根据IA破裂出血与否分为IA破裂组(n=46)和IA未破裂组(n=44),收集两组临床资料,对比两组患者CTA影像瘤体特征参数和PHASES评分结果。采用受试者工作特征(ROC)曲线分析两者联合预测动脉瘤破裂的效能。结果:IA破裂组高血压、糖尿病发生率及PHASES评分均高于IA未破裂组,差异有统计学意义(P <0.05)。两组病灶位置以颈内动脉(ICA)和大脑中动脉(MCA)为主,但IA破裂组病灶位置在MCA的占比为41.30%,高于IA未破裂组的20.45%,瘤体>7 mm的最多(瘤体7~9.9 mm占65.22%),瘤体形态不规则占58.7%,未破裂组病灶位置在ICA最多(68.18%),瘤体<7 mm的居多(75.00%),瘤体形态规则囊状动脉瘤占93.18%,差异有统计学意义(P <0.05)。CTA瘤体特征参数比较,IA破裂组患者瘤颈宽度、瘤体高度、瘤体长度、动脉瘤最大直径、入射夹角、动脉瘤体颈比等参数均高于IA未破裂组,差异有统计学意义(P <0.05)。CTA瘤体特征参数+PHASES评分联合预测曲线下面积为0.916,高于CTA瘤体特征参数(0.901)和PHASES评分(0.731)。结论:CTA瘤体特征参数+PHASES评分联合预测IA患者破裂出血效能最佳。 展开更多
关键词 颅内动脉瘤 破裂出血 CTA phaseS评分
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Constructing Crystalline g-C_(3)N_(4)/g-C_(3)N_(4-x)S_(x)Isotype Heterostructure for Efficient Photocatalytic and Piezocatalytic Performances 被引量:2
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作者 Tingting Xu Zhonghui Xia +3 位作者 Hongguan Li Ping Niu Shulan Wang Li Li 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2023年第2期8-16,共9页
Graphitic carbon nitride(g-C_(3)N_(4))is viewed as a promising visible-light photocatalyst for industrialization due to its low processing temperature and high chemical stability.However,serious charge recombination c... Graphitic carbon nitride(g-C_(3)N_(4))is viewed as a promising visible-light photocatalyst for industrialization due to its low processing temperature and high chemical stability.However,serious charge recombination caused by incomplete polymerization during direct calcination of nitrogen-rich precursors significantly limits its photocatalytic performances.To boost charge separation,herein,we propose a rational strategy by constructing a crystalline g-C_(3)N_(4)/g-C_(3)N_(4-x)S_(x) isotype heterostructure through the molten salt method.Theoretical calculation reveals that apparent charge-transfer channels are formed between g-C_(3)N_(4) and S-doped g-C_(3)N_(4) layers in the heterostructure.Owing to high crystallinity for decreasing charge recombination and isotype heterostructure for efficient charge transfer,the as-prepared g-C_(3)N_(4)/g-C_(3)N_(4-x)S_(x) showed remarkable photocatalytic performances with the hydrogen production rate elevated by up to 12.3 times of its singular components.Another novelty of this work is we investigated for the first time the piezocatalytic activity of crystalline g-C_(3)N_(4) by characterizing its performance for H2O2 generation and KMnO4 reduction.Strikingly,its superior piezocatalytic performance over components can be further improved by NaBH4 treatment,which is uncovered to enhance the asymmetric structure of crystalline g-C_(3)N_(4) by introducing extra cyano groups and removing partial NHx species in its tri-s-triazine layer structure.This work opens up new strategies for the design of highly efficient polymeric photocatalysts and highlights the piezocatalytic studies of g-C_(3)N_(4). 展开更多
关键词 carbon nitride high crystallinity isotype heterostructure photocatalysis piezoelectric catalysis
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Synthesis of steel slag ceramics: chemical composition and crystalline phases of raw materials 被引量:3
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作者 Li-hua Zhao Wei Wei +2 位作者 Hao Bai Xu Zhang Da-qiang Cang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2015年第3期325-333,共9页
Two types of porcelain tiles with steel slag as the main raw material (steel slag ceramics) were synthesized based on the CaO-A1203-SiO2 and CaO--MgO-SiO2 systems, and their bending strengths up to 53.47 MPa and 99.... Two types of porcelain tiles with steel slag as the main raw material (steel slag ceramics) were synthesized based on the CaO-A1203-SiO2 and CaO--MgO-SiO2 systems, and their bending strengths up to 53.47 MPa and 99.84 MPa, respectively, were obtained. The presence of anorthite, a-quartz, magnetite, and pyroxene crystals (augite and diopside) in the steel slag ceramics were very different from the composition of traditional ceramics. X-ray diffraction (XRD) and electron probe X-ray microanalysis (EPMA) results illustrated that the addition of steel slag reduced the temperature of extensive liquid generation and further decreased the firing temperature. The considerable contents of glass-modifying oxide liquids with rather low viscosities at high temperature in the steel slag ceramic adobes promoted element diffusion and crystallization. The results of this study demonstrated a new approach for extensive and effective recycling of steel slag. 展开更多
关键词 ceramic materials SYNTHESIS steel slag chemical composition crystalline phases solid waste recycling
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Synthesis and Phase Behavior of Poly(1-alkyne) with Liquid Crystalline-induced Luminescence Enhancement 被引量:2
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作者 ZHOU Dan CHEN Yi-wang CHEN Lie LI Fan NIE Hua-rong YAO Kai 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2010年第6期1035-1044,共10页
Poly(1-alkyne) with octoxy spacer —{[HC=C(CH2)8O—terphenyl—CN]}n—(PA8CN) and terphenyl liquid crystalline pendant was synthesized,and the effects of structure on the optical properties,especially the liquid ... Poly(1-alkyne) with octoxy spacer —{[HC=C(CH2)8O—terphenyl—CN]}n—(PA8CN) and terphenyl liquid crystalline pendant was synthesized,and the effects of structure on the optical properties,especially the liquid crystallinity behavior of the polymer and monomer were investigated.The monomer was prepared in high yields(92.30%) by coupling and etherification reactions and successfully polymerized in the presence of Rh catalyst and Et3N cocatalyst in high yields with trans-rich(86.27%) stereoregular structure.Compared to the monomer showing mixed monolayer structure,its corresponding polymer PA8CN formed homogeneous monolayer arrangement.Upon photoexcitation,strong blue emission peak of PA8CN appeared at 413 nm[fluorescence quantum yield,ΦF = 68% when excited at 330 nm in tetrahydrofuran(THF) solution].Compared with its solid film photoexcitated at 330 nm at room temperature,the UV light-emitting band of PA8CN solid film from its liquid crystalline with liquid nitrogen quenched rapidly at 236 ℃ was red-shift 10 nm with higher intensity,which may be ascribed to the fact that the effectual conjugation and the order degree of the molecule in the liquid crystalline state of the polymer were enhanced,the energy loss caused by the thermal vibration was decreased,thus resulting in the observed hyperchromic effect. 展开更多
关键词 POLYACETYLENE Liquid crystallinity phase transition PHOTOLUMINESCENCE
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Crystalline Phase and Decomposition Dynamics of Aluminum Titanate at Different Temperature 被引量:2
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作者 林寿 阮玉忠 +1 位作者 沈阳 罗金荣 《Chinese Journal of Structural Chemistry》 SCIE CAS CSCD 2012年第1期79-84,共6页
The crystalline phase formed during aluminum titanate at 750-1300 ℃ as well as the relationship between its content change and decomposition dynamics was mainly discussed in this paper.Dynamical equation was establis... The crystalline phase formed during aluminum titanate at 750-1300 ℃ as well as the relationship between its content change and decomposition dynamics was mainly discussed in this paper.Dynamical equation was established for calculating the reaction activation energy.It aimed at providing dynamics basic data for taking up necessary measures to inhibit the decomposition of aluminum titanate.Experimental results showed that aluminum titanate would decompose into TiO2 and corundum at 750-1300 ℃.Content of aluminum titanate would reduce with the increase of decomposition time,and the order of decomposition rates at different temperature was 1100 1200 1000 900 ℃.The decomposition was a chemical reaction with control steps,and could meet the first order reaction dynamic equation-F(G) = [(1-G)-2/3-1] = Kt.According to the calculation,rate constants of different decomposition reaction dynamic equations were K900 = 2.2×10-3,K1000 = 1.2×10-2,K1100 = 4×10-1 and K1200 = 1.5×10-1,and the reaction activation energy ΔGave = 203.21 KJ/mol. 展开更多
关键词 aluminum titanate decomposition crystalline phase decomposition dynamics
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Effect of Solution Concentration on the Electrospray/Electrospinning Transition and on the Crystalline Phase of PVDF 被引量:7
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作者 Lígia Maria Manzine Costa Rosário Elida Suman Bretas Rinaldo Gregorio 《Materials Sciences and Applications》 2010年第4期247-252,共6页
A study was conducted regarding the effect of concentration of poly (vinylidene fluoride) (PVDF)/N,N-dimethylformamide (DMF) and PVDF/DMF/acetone solutions on the transition between electrospray and electrospinning an... A study was conducted regarding the effect of concentration of poly (vinylidene fluoride) (PVDF)/N,N-dimethylformamide (DMF) and PVDF/DMF/acetone solutions on the transition between electrospray and electrospinning and on the formation of the ? and ? crystalline phases of PVDF. The crystalline phases present in the samples, crystallinity and morphology were determined by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and scanning electron microscopy (SEM), respectively. Low concentration solutions resulted in films consisting of small droplets (electrospray) containing predominantly the ? phase. High concentration solutions resulted in a non-woven mesh of nano-to-micron diameter fibers (electrospinning) containing exclusively the ? phase. These results showed that, the formation of this phase in the electrospinning is related mainly to the solvent evaporation rate, and not to drawing experienced by the polymer during the process. Solvent type affected the amount of crystalline phase present, the boundary concentration between the two processes and the average diameter of fibers. Meshes processed by electrospinning display a degree of crystallinity higher than the films obtained by electrospray. 展开更多
关键词 Poly(Vinylidene Fluoride) (PVDF) ELECTROSPINNING ELECTROSPRAY crystalline phase Fibers Morphology
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