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Temperature-triggered phase transition in pyridazine hexafluorophosphate

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Chinese Chemical Letters 2015年第1期26卷 145-148页

作者： Dong-Yan Wang Li-Li Qin Xue-Li Hou heng-yun ye Ordered Matter Science Research Center Southeast University

The pyndazine hexafluorophosphate[C4H5N2]~＋[PF6]^-（1） undergoes a reversible phase transition around140 K,which was confirmed by the DSC measurement.Variable-temperature crystal structures determined at 293 K and 93 K show that the compound crystallizes in the same space group P21/c,indicating that 1 undergoes an iso-structural phase *** the temperature decreases,dielectric measurement of the title compound shows no significant change around the phase transition *** hydrogen bonds are found between molecules at 293 K and 93 l〈 with similar packing *** most distinct difference between the low temperature and room temperature structures is the order-disorder transition of the hexafluorophosphate anion,which is probably the driving force of the phase transition.

关键词： Phase transition Dielectric DSC Crystal structure

Iso-structural phase transition in tetramethylammonium nickel(Ⅱ)nitrite[(CH_3)_4N][Ni(NO_2)_3]

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Chinese Chemical Letters 2014年第6期25卷 844-848页

作者： Li-Hui Kong Da-Wei Fu Qiong ye heng-yun ye Yi Zhang Ren-Gen Xiong Ordered Matter Science Research Center Southeast University

The title compound, tetramethylammonium nickel nitrite [（CH3）4N][Ni（NO2）3], has a hexagonal perovskite-type structure with formula ABX3. It undergoes two reversible phase transitions occurring at about 409.1 and 428.4 K, associated with dielectric transitions. DSC measurement and dielectric measurement confirm the transition. The variable-temperature X-ray structural determinations and the powder X-ray diffraction （PXRD） experiments reveal that this compound has the same space group P3ml （No. 164） at 293 K, 413 K and 438 K. The phase transitions are caused by the rotation of the [（CH3）4N]＋ cation.

关键词： Phase transition Dielectric DSC PXRD X-ray structural Perovskite-type structure

Enantiomeric hybrid high-temperature multiaxial ferroelectrics with a narrow bandgap and high piezoelectricity

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中国化学快报:英文版 2023年第8期34卷 462-466页

作者： Chang-Feng Wang Na Wang Lang Liu Le-Ping Miao heng-yun ye Yi Zhang Chao Shi Chaotic Matter Science Research Center Department of MaterialsMetallurgy and ChemistryJiangxi University of Science and TechnologyGanzhou 341000China

Ferroelectric semiconductors have sparked growing attention in the field of optoelectronics,due to their unique ferroelectric photovoltaic ***,substantial efforts have been devoted to the development of ferroelectric semiconductors,including inorganic oxides,organic-inorganic hybrids,and metal-free ***,reports of ferroelectric semiconductors with a bandgap of less than 2 eV have been ***,in combination with the incorporation of triiodide(I_(3)−)and the introduction of chiral cations,we successfully constructed a pair of enantiomeric organic-inorganic hybrid ferroelectric semiconductors,(S-1,2-DAP·I)_(4)·I_(3)·BiI_(6)and(R-1,2-DAP·I)_(4)·I_(3)·BiI_(6)(R/S-1,2-DAP=(R/S)-(–)-1,2-diaminopropane),which possess high-temperature multiaxial ferroelectric phase transition with an Aizu notation of 422F2(s)at 405 K,a narrow bandgap of 1.56 eV comparable to that of CH3NH3PbI_(3)(∼1.5 eV),and an impressive piezoelectric response(piezoelectric coefficient,d22 of 35 pC/N)on par with PVDF(polyvinylidene fluoride,30 pC/N).With intriguing attributes,(S-1,2-DAP·I)_(4)·I_(3)·BiI_(6)and(R-1,2-DAP·I)_(4)·I_(3)·BiI_(6)exhibit great potential for application of self-power polarized-light detection and piezoelectric sensors.

关键词： Chirality Hybrid materials Multiaxial ferroelectrics Semiconductors Piezoelectricity

A new insight into the unique magneto-optical effect of layered perovskite(C_(6)H_(5)C_(2)H_(3)FNH_(3))_(2)MnCl_(4)

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聚集体(英文) 2023年第3期4卷 120-125页

作者： Zhao-Bo Hu Long-He Li Yibo Han Jinlei Zhang Jianrong Li Zilu Chen ShuyiWu Yi Zhang heng-yun ye You Song State Key Laboratory of Coordination Chemistry School of Chemistry and Chemical EngineeringNanjing UniversityNanjingPR China Chaotic Matter Science Research Center Faculty of Materials Metallurgy and ChemistryJiangxi University of Science and TechnologyGanzhouPR China Jiangxi Provincial Key Laboratory of Functional Molecular Materials Chemistry Jiangxi University of Science and TechnologyGanzhouPR China Wuhan National High Magnetic Field Center and School of Physics Huazhong University of Science and TechnologyWuhanPR China Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application School of Physical Science and TechnologySuzhou University of Science and TechnologySuzhouPR China State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources School of Chemistry and Pharmaceutical SciencesGuangxi Normal UniversityGuilinPR China

Magnet-optical materials embracing coupled magnetic and photoluminescent properties in single phase are promising in microelectronics and optoelectronic ***,the current research mainly focuses on traditional inorganic materials,and there are few reports on molecule ***,we synthesized an organic–inorganic hybrid complex((C_(6)H_(5)C_(2)H_(3)FNH_(3))_(2)MnCl_(4)(1)with perovskite *** measurements show that 1 not only behaves as an antiferromagnet with spin canting but also exhibits unusual fluorescent ***,under the magnetic field at different temperatures,the luminous intensity of 1 changed,and a red-shift occurred with obviously optical *** phenomena directly prove the existence of magneto-optical coupling in *** interestingly,the optical hysteresis can be observed in both low and high field,which is unprecedented in other molecular *** in traditional inorganic materials,it can only be observed in strong *** special function provides the possibility for the application of low energy consumption optoelectronic devices.

关键词： magnetic order magneto-optical effect optical hysteresis optical phenomena

NH_(+)^(4)/K^(+)-substitution-induced C–F–K coordination bonds for designing the highest-temperature hybrid halide double perovskite ferroelastic

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Chinese Chemical Letters 2023年第7期34卷 364-367页

作者： Chang-Feng Wang Na Wang Chao Shi heng-yun ye Yi Zhang Le-Ping Miao Chaotic Matter Science Research Center Department of MaterialsMetallurgy and Chemistry.Jiangxi University of Science and TechnologyGanzhou 341000.China

Ferroelastic materials with switchable spontaneous strain possess widely potential applications in the field of energy and information ***,organic-inorganic hybrid halide double perovskites (OIHHDPs) have become a charming new platform for developing various functional materials,such as ferroelectrics,fluorescence and X–ray ***,OIHHDP ferroelastic materials,especially high-temperature ones,are ***,we initially synthesized an OIHHDP ferroelastic,(2,2-difluoroethanamine)_(2)[(NH_(4))InCl_6](1),which possesses a ferroelastic phase transition at 407 ***,thanks to the flexible B-site for OIHHDPs,we replaced the NH_(4)^(+) ions within[(NH_(4))InCl_6]_n^(2n–)formworks with K^(+)ions,which endows with coordination bonds between 2,2-difluoroethanamine organic cations and[KInCl_6]_n^(2n–)*** to the existence of coordination bonds,the phase transition temperature of (2,2-difluoroethanamine)_(2)[KInCl_6](2) can reach 458 *** far as we know,this value is the highest reported in OIHHDP *** work offers inspiration for the design of high-temperature OIHHDP phase transition materials including ferroelectrics and ferroelastics.

关键词： Lead-free Hybrid halide double perovskites Ferroelastics Phase transition Order-disorder

A DERIVATIVE-HILBERT OPERATOR ACTING FROM LOGARITHMIC BLOCH SPACES TO BERGMAN SPACES

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Acta Mathematica Scientia 2024年第5期44卷 1916-1930页

作者： Shanli ye yun XU School of Science Zhejiang University of Science and TechnologyHangzhou310023China

Letμbe a positive Borel measure on the interval[0,1).The Hankel matrix■with entriesμn,k=μn+k,whereμn=⨜[0,1)tndμ(t),induces,formally,the operator■where■is an analytic function *** characterize the measuresμfor which■is bounded(resp.,compact)operator from the logarithmic Bloch space■into the Bergman space■,where 0≤α<∞,0

关键词： derivative-Hilbert operator logarithmic Bloch space Carleson measure

Drinking water quality & health risk assessment of secondary water supply systems in residential neighborhoods

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Frontiers of Environmental Science & Engineering 2024年第2期18卷 47-62页

作者： Yating Wei Dong Hu Chengsong ye heng Zhang Haoran Li Xin Yu College of the Environment&Ecology Xiamen UniversityXiamen 361102China School of Public Health Shandong First Medical University&Shandong Academy of Medical SciencesJinan 250117China

Secondary water supply systems(SWSSs)are important components of the water supply infrastructure that ensure residents’drinking water *** are characterized by long detention time,warm temperature,and unreasonable management,which may trigger the deterioration of water quality and increase *** this study,drinking water quality index(DWQI)and health risk assessment(HRA)were selected and modified to quantitatively assess the water quality and health risks of SWSSs in residential *** total,121 seasonal water samples were *** was observed that the water quality was excellent with the DWQI of 0.14±0.04,excluding one sample,which was extremely poor owing to its excessive total bacterial *** HRA results revealed that the health risks were low:negligible non-carcinogenic risk for any population;negligible and acceptable carcinogenic risk for children aged 6–17 and ***,samples revealed higher carcinogenic risk(7.63×10−5±3.29×10−6)for children aged 0–5,and arsenic was the major *** samples had poor water quality and higher health risks,which called for *** further investigate the water quality and health risks of SWSSs,monthly sampling was conducted during *** 24 water samples were qualified in Chinese standard(GB 5749-2022)and characterized as excellent *** HRA results were consistent with the seasonal samples’and the health risks were mainly concentrated in ***,our study provides a suitable framework for water quality security,advice for managers,and references for administrators in other cities.

关键词： Drinking water quality Water quality index Health risk assessment Secondary water supply systems Heavy metals

Degradation-adaptive neural network for jointly single image dehazing and desnowing

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Frontiers of Computer Science 2024年第2期18卷 247-249页

作者： Erkang CHEN Sixiang CHEN Tian ye yun LIU School of Ocean Information Engineering Jimei UniversityXiamen 361021 China College of Artificial Intelligence Southwest UniversityChongqing 400715 China

1 Introduction In harsh winter scenes,the captured images often suffer from hazeand snowdegradationssimultaneously,which significantly affect the performance of high-level computer vision ***,most existing dehazing methods[1-4]and desnowing methods[5-7]are specialized to address only one type of weather-related degradation,and they struggle to effectively handle multiple types of degradations.

关键词： neural handle computer

Deep decalcification of factory-provided freezing acidolysis solution to achieveα-high-strength gypsum

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Chinese Journal of Chemical Engineering 2024年第5期69卷 143-151页

作者： Wencai ye Yulu Li Yonggang Dong Lin Yang yun Yi Jianxin Cao School of Chemistry and Chemical Engineering Guizhou UniversityGuiyang 550025China Engineering Research Center of Efficient Utilization for Industrial Waste Guizhou UniversityGuiyang 550025China Key Laboratory of Guizhou Province for Green Chemical Industry and Clean Energy Technology Guizhou UniversityGuiyang 550025China

The freezing acidolysis solution of the nitric acid-phosphate fertilizer process has a high calcium content,which makes it difficult to produce fine phosphate and high water-soluble phosphate fertilizer ***,based on the potential crystallization principle of calcium sulfate in NH_(4)NO_(3)-H_(3)PO_(4)-H_(2)O,the deep decalcification(*** removal)technology to achieveα-high-strength gypsum originated from freezing acidolysis-solutions has been firstly proposed and ***,calcium can be removed from the factory-provided freezing acidolysis-solution by neutralizing it with ammonia,followed by the addition of ammonium sulfate *** a result,the formation of calcium sulfate in the reaction system undergoes the nucleation and growth of CaSO_(4)·2H_(2)O(DH),as well as its dissolution and crystallization into short columnarα-CaSO_(4)·0.5H_(2)O(α-HH).Remarkably,with the molar ratio of SO_(4)^(2-)/Ca^(2+)at 1.8,the degree of neutralization(NH_(3)/HNO_(3) molar ratio)at 1.7,the reaction temperature of 94℃,and the reaction time of 300 min,the decalcification rate can reach 86.89%,of which the high-strengthα-CaSO_(4)·0.5H_(2)O(α-HH)will be ***,the deep decalcification product meets the standards for the production of fine phosphates and highly water-soluble phosphate ***,the 2 h flexural strength ofα-HH is 5.3 MPa and the dry compressive strength is 36.8 MPa,which is up to the standard of commercialα-HH.

关键词： Nitrophosphate Ammonia neutralization Deep decalcification High-strengthα-hemihydrate gypsum Controlled crystallization at atmospheric pressure