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Rational molecular design of efficient yellow-red dendrimer TADF for solution-processed OLEDs: a combined effect of substitution position and strength of the donors

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science China Chemistry 2024年第5期67卷 1613-1623页

作者： Changfeng si Dianming sun Tomas matulaitis David B.Cordes Alexandra m.Z.slawin Eli Zysman-Colman Organic semiconductor Centre EaStCHEM School of ChemistryUniversity of St AndrewsSt AndrewsKY169STUK

The development of high-performance solution-processed red organic light-emitting diodes(OLEDs) remains a challenge,particularly in terms of maintaining efficiency at high luminance. Here, we designed and synthesized four novel orange-red thermally activated delayed fluorescence(TADF) dendrimers that are solution-processable: 2GCz BP, 2DPACz BP, 2FBP2GCz and 2FBP2DPACz. We systematically investigated the effect of substitution position and strength of donors on the optoelectronic properties. The reverse intersystem crossing rate constant(kRIsC) of the emitters having donors substituted at positions 11and 12 of the dibenzo[a,c]phenazine(BP) is more than 10-times faster than that of compounds substituted having donors substituted at positions 3 and 6. Compound 2DPACz BP, containing stronger donors than 2GCz BP, exhibits a red-shifted emission and smaller singlet-triplet energy splitting, ΔE_(sT), of 0.01 e V. The solution-processed OLED with 10 wt% 2DPACz BP doped in m CP emitted at 640 nm and showed a maximum external quantum efficiency(EQE_(max)) of 7.8%, which was effectively maintained out to a luminance of 1,000 cd m-2. such a device's performance at relevant display luminance is among the highest for solution-processed red TADF OLEDs. The efficiency of the devices was improved significantly by using 4Cz IPN as an assistant dopant in a hyperfluorescence(HF) configuration, where the 2DPACz BP HF device shows an EQEmaxof 20.0% at λEL of 605 nm and remains high at 11.8% at a luminance of 1,000 cd m-2, which makes this device one of the highest efficiency orange-to-red HF sP-OLEDs to date.

关键词： thermally activated delayed fluorescence solution-processing red OLEDs dibenzo[a,c]phenazine dendrimers

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Ramsey Numbers of Trees Versus multiple Copies of Books

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Acta mathematicae Applicatae sinica 2024年第3期40卷 600-612页

作者： Xiao-bing GUO si-nan HU Yue-jian PENG school of mathematical sciences Luoyang Normal UniversityLuoyang 471934China school of mathematics Hunan UniversityChangsha 410082China

Given two graphs G and H,the Ramsey number R(G,H) is the minimum integer N such that any two-coloring of the edges of K_(N) in red or blue yields a red G or a blue *** v(G) be the number of vertices of G and χ(G) be the chromatic number of *** s(G) denote the chromatic surplus of G,the number of vertices in a minimum color class among all proper χ(G)-colorings of *** showed that R(G,H)≥(v(G)-1)(χ(H)-1)+s(H) if G is connected and v(G)≥s(H).A connected graph G is H-good if R(G,H)=(v(G)-1)(χ(H)-1)+s(H).Let tH denote the disjoint union of t copies of graph H,and let G∨H denote the join of G and *** a complete graph on n vertices by K_(n),and a tree on n vertices by T_(n).Denote a book with n pages by B_(n),i.e.,the join K_(2) ∨■.Erd?s,Faudree,Rousseau and schelp proved that T_(n) is B_(m)-good if n≥*** this paper,we obtain the exact Ramsey number of T_(n) versus 2B_(2).Our result implies that T_(n) is 2B_(2)-good if n≥5.

关键词： ramsey number ramsey goodness tree book

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Engineering of efficient visible light photocatalysts:Ti_(1-x+y)Cu_(x)La_(y)O_(2)(x=0.03;y=0,0.005,0.01) compositions

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Journal of Rare Earths 2024年第3期42卷 497-505,I0003页

作者： s.m.Yakout A.m.Youssef Inorganic Chemistry Department National Research Centre(NRC)El Buhouth StDokkiCairo12622Egypt

In dye-photocatalysis, widening the wavelengths absorption range of catalysts as well as aborting the recombination of the photoexcited charge carriers(electrons-holes pairs) are of paramount *** the current study, we report the photocatalytic characteristics of four compositions composed of TiO_(2),Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders for two harmful dyes(Congo red and methylene blue). The X-ray diffraction technique verified the configuration of mixed anatase and rutile phases in pure TiO_(2)and Ti_(0.97)Cu_(0.03)O_(2)powders while Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders possess anatase phase only. The changes of the band gap structure and dimensions of the unit cell volume of TiO_(2)confirm the substitution of Ti^(4+)sites by Cu^(2+)and La^(3+)ions. Remarkable widening of wavelengths absorption with formation of long absorption tails were found in TiO_(2)(3.13 e V) through insertion of La^(3+)plus Cu^(2+)ions. Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)samples exhibit a visible light band gap of 2.3 and 2.7 e V, respectively. Based on sEm images, incorporation of Cu^(2+)and La^(3+)ions influences the surface morphology of TiO_(2). The resulting Ti_(0.97)Cu_(0.03)O_(2), Ti_(0.965)Cu_(0.03)La_(0.005)O_(2)and Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)powders present enhanced photocatalytic activity towards Congo red dye degradation compared to pure one under natural solar spectrum. The best Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst exhibits superior photocatalytic activity of 96% for 10 ppm CR dye in 20 min as well as above average photocatalytic efficiency of 63% for 30 ppm CR dye in 120 min. As well, it showed acceptable photodegradation activity of 52% for 30 ppm mB solution in 140 min of sunlight irradiation. The heightened photodegradation efficiency of Ti_(0.96)Cu_(0.03)La_(0.01)O_(2)catalyst can be clarified in terms of higher ch

关键词： semiconductor TiO_(2) Rare earths Congo red methylene blue solar spectrum Photodegradation

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Efficacy and safety of Yangxinshi tablet for chronic heart failure:A systematic review and meta-analysis

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World Journal of Clinical Cases 2024年第13期12卷 2218-2230页

作者： sheng-Hua Lu Yun-Feng Yu si-si Dai Ya-Qi Hu Jian-He Liu The First Clinical College of Chinese medicine Hunan University of Chinese MedicineChangsha 410007Hunan ProvinceChina Branch of National Clinical Research Center for Chinese medicine Cardiology The First Hospital of Hunan University of Chinese MedicineChangsha 410007Hunan ProvinceChina

BACKGROUND The specific benefits of Yangxinshi tablet(YXsT)in the treating chronic heart failure(CHF)remain *** To systematically evaluate the efficacy and safety of YXsT in the treatment of *** Randomized controlled trials(RCTs)investigating YXsT for CHF treatment were retrieved from eight public databases up to November ***-analyses of the included clinical studies were conducted using Review manager *** Twenty RCTs and 1845 patients were *** meta-analysis results showed that the YXsT combination group,compared to the conventional drug group,significantly increased the clinical efficacy rate by 23%[relative risk(RR)=1.23,95%CI:1.17-1.29],(Pmean difference(mD)=6.69,95%CI:4.42-8.95,Pmin walk test by 49.82 m(mD=49.82,95%C:38.84-60.80,Pminal pro-Btype natriuretic peptide by 1.03 ng/L[standardized mD(smD)=-1.03,95%CI:-1.32 to-0.74,PmD=-80.95,95%CI:-143.31 to-18.59,P=0.01),left ventricular end-diastolic diameter by 3.92 mm(mD=-3.92,95%CI:-5.06 to-2.78,Psystolic diameter by 4.34 mm(mD=-4.34,95%CI:-6.22 to-2.47,Psafety,neither group reported any serious adverse events during treatment(RR=0.54,95%CI:0.15-1.90,P=0.33).In addition,Egger's test results indicated no significant publication bias(P=0.557).CONCLUsiON YXsT effectively improves clinical symptoms and cardiac function in patients with CHF while maintaining a favorable safety profile,suggesting its potential as a therapeutic strategy for CHF.

关键词： Yangxinshi tablet Chronic heart failure Cardiac function systematic evaluation meta-analysis

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^(4)He monolayer on graphene:a quantum monte Carlo study

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Communications in Theoretical Physics 2024年第9期76卷 149-157页

作者： s Yu m Boninsegni Department of Physics University of AlbertaEdmontonAlbertaT6G 2H5Canada

We revisit the problem of adsorption of a single^(4)He layer on graphene,focusing on the commensurate(C_(1/3))crystalline phase,specifically on whether it may possess a nonzero superfluid response,and on the existence of superfluid phases,either(metastable)liquid or vacancy-doped *** make use of canonical quantum monte Carlo simulations at zero and finite temperature,based on a realistic microscopic model of the *** results confirm the absence of any superfluid response in the commensurate crystal,and that no thermodynamically stable uniform phase exists at lower *** evidence of a possibly long-lived,metastable superfluid phase at C_(1/3)coverage is ***,the results of ground-state projection methods and finite-temperature simulations are entirely consistent.

关键词： superfluidity low-dimensional systems quantum monte Carlo helium supersolids

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Direct microwave leaching conditions of rare earth elements in fluorescent wastes

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Journal of Rare Earths 2024年第6期42卷 1165-1174,I0007页

作者： A.Bilen B.Birol m.N.saridede s.s.Kaplan m.s.sonmez Department of metallurgical and materials Engineering Yildiz Technical UniversityIstanbulTurkey Department of Chemical Engineering and materials science Stevens Institute of TechnologyNew JereyUSA Department of metallurgical and materials Engineering Istanbul Technical UniversityIstanbulTurkey

The luminescent phosphor powder in the fluorescent lamp constitutes 2%of the lamp’s *** can be mentioned that fluorescent wastes are a crucial raw material to produce rare earth *** the present study,microwave leaching process was conducted to dissolve rare earth elements yttrium(Y),europium(Eu),and remaining rare earth elements(REEs)present in the phosphor powder of the fluorescent *** the yields were *** the microwave leaching process,the effects of the temperature(80-160℃),acid type(hydrochloric acid(HCl),nitric acid(HNO_(3)),sulphuric acid(H_(2)sO_(4))),acid concentration(0.5-6 mol/L),solid to liquid ratio(0.1:10-0.5:10)and reaction time(5-90 min)parameters on leaching efficiencies of varying rare earth elements and calcium were *** highest yield was obtained in the direct microwave leaching of fluorescent waste with the experimental conditions of 6 mol/L HCl,160℃,0.1:10 solid-to-liquid ratio(s:L),and 90 *** energy calculations were made,and kinetic models of the reactions were obtained,and it is observed that Y and Eu dissolution is diffusion-controlled,on the other hand,lanthanum(La),cerium(Ce),and terbium(Tb)were examined to be chemical reaction ***,calcium(Ca)and gadolinium(Gd)seem coherent with the mixed ***,mathematical models of all experimental studies are created with the response surface Box-Behnken method and the correlation coefficients of all the models are over 90%.

关键词： Rare earth elements(REEs) Direct microwave leaching Fluorescent waste Kinetic models Response surface method

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Wettability Gradient-Induced Diode:mXene-Engineered membrane for Passive-Evaporative Cooling

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Nano-micro Letters 2024年第8期16卷 382-397页

作者： Leqi Lei shuo meng Yifan si shuo shi Hanbai Wu Jieqiong Yang Jinlian Hu Department of Biomedical Engineering City University of Hong KongHong Kong S.A.R 999077China

Thermoregulatory textiles,leveraging high-emissivity structural materials,have arisen as a promising candidate for personal cooling management;however,their advancement has been hindered by the underperformed water moisture transportation capacity,which impacts on their thermophysiological ***,we designed a wettability-gradient-induced-diode(WGID)membrane achieving by mXene-engineered electrospun technology,which could facilitate heat dissipation and moisture-wicking *** a result,the obtained WGID membrane could obtain a cooling temperature of 1.5℃ in the“dry”state,and 7.1℃ in the“wet”state,which was ascribed to its high emissivity of 96.40%in the mIR range,superior thermal conductivity of 0.3349 W m^(-1) K^(-1)(based on radiation-and conduction-controlled mechanisms),and unidirectional moisture transportation *** proposed design offers an approach for meticulously engineering electrospun membranes with enhanced heat dissipation and moisture transportation,thereby paving the way for developing more efficient and comfortable thermoregulatory textiles in a high-humidity microenvironment.

关键词： Passive-evaporative cooling mXene Electrospun membrane Wettability gradient Diode

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superatom-assembled boranes,carboranes,and low-dimensional boron nanomaterials based on aromatic icosahedral B_(12)and C_(2)B_(10)

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Nano Research 2024年第7期17卷 6734-6740页

作者： Qiao-Qiao Yan Yan-Fang Wei Qiang Chen Yue-Wen mu si-Dian Li Institute of molecular science Shanxi UniversityTaiyuan 030006China

Using the experimentally known aromatic icosahedral superatoms I_(h)B_(12)H_(12)2−and D_(5d)1,12-C_(2)B_(10)H_(12)as building blocks and based on extensive density functional theory calculations,we predict herein a series of core–shell superpolyhedral boranes and carboranes in a bottom-up approach,including the high-symmetry Th B_(12)@B_(152)H_(72)2−(2),C2h C_(2)B_(10)@B_(152)H_(72)(3),D_(3d)B_(12)@B_(144)H_(66)(4),I_(h)B_(12)@C_(24)B_(12)0H_(72)2−(6),and D_(5d)C_(2)B_(10)@C_(24)B_(12)0H_(72)(7).more interestingly,the superatom-assembled linear D2h B_(36)H_(32)^(2−)(8),close-packed planar D_(3d)B_(84)H_(60)^(2−)(10),and nearly close-packed core−shell D_(3d)B_(12)@B144H_(6)6(4)can be extended periodically to form the one-dimensional(1D)α-rhombohedral borane nanowire B_(12)H_(10)(Pmmm)(9),two-dimensional(2D)α-rhombohedral monolayer borophane B_(12)H_(6)(P m1)(11),and the experimentally known three-dimensional(3D)α-rhombohedral boron(R m)(12)which can be viewed as an assembly of the monolayer B_(12)H_(6)(11)staggered in vertical direction,setting up a bottom-up strategy to form low-dimensional boron-based nanomaterials from their borane“seeds”via partial or complete *** bonding analyses indicate that the high stability of these nanostructures originates from the spherical aromaticity of their icosahedral B_(12)or C_(2)B_(10)structural units which possess the universal skeleton electronic configuration of 1s21P61D101F8 following the Wade’s n+1 *** infrared(IR)and Raman spectra of the most-concerned neutral B_(12)@B144H_(6)6(4)and C_(2)B_(10)@C_(24)B_(12)0H_(72)(7)are computationally simulated to facilitate their experimental characterizations.

关键词： superatom-assembling bottom-up approach density functional theory superpolyhedral boranes superpolyhedral carboranes borophanes

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Parametric investigation on the novel and cost-effective nano fly ash impregnated geopolymer system for sustainable construction

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Frontiers of structural and Civil Engineering 2024年第2期18卷 170-183页

作者： R.mOHANA s.m.Leela BHARATHI Department of Civil Engineering Mepco Schlenk Engineering CollegeSivakasi 626123India

The hazardous environmental effects of greenhouse gas emissions and climate change demand alternative sources for cementitious materials in the construction *** development of geopolymer structures provides a way of producing 100%cement-free *** this research work,a novel and simple way of deriving nano particles from waste fly ash particles is *** effect of adding the synthesized nano fly ash particles as a filler medium in geopolymer mortars was investigated by considering strength and durability *** optimization was done by using regression analysis on the geopolymer mortar and the impact of adding nano fly ash particles was studied by varying different percentages of addition ranging from 0 to 7.5%by weight of binder *** the results,it was observed that 1%nano fly ash acted not only as a filler but also as nano-sized precursors of the polymerization process,resulting in denser geopolymer *** can explain the extraordinary gain in strength of 72.11 mPa as well as the denser core with negligible level of chloride ion penetration,making the material suitable for the development of structures susceptible to marine environment.

关键词： geopolymer nano fly ash chloride ion penetration durability polymerization fillers

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New insights into protein–polysaccharide complex coacervation:Dynamics,molecular parameters,and applications

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Aggregate 2024年第1期5卷 148-166页

作者： Jiabao Zheng Paul Van der meeren Weizheng sun school of Food science and Engineering South China University of TechnologyGuangzhouChina Department of Green Chemistry and Technology Faculty of Bioscience EngineeringGhent UniversityGhentBelgium Overseas Expertise Introduction Center for Discipline Innovation of Food Nutrition and Human Health(111 Center) GuangzhouChina

For more than a decade,the discovery of liquid–liquid phase separation within living organisms has prompted colloid scientists to understand the connection between coacervate functionality,phase behavior,and dynamics at a multidisciplinary *** the protein–polysaccharide was the first system in which the coacervation phenomenon was discovered and is widely used in food systems,the phase state and relaxation dynamics of protein–polysaccharide complex coacervates(PPCC)have rarely been discussed ***,this review aims to unravel the relationship between PPCC dynamics,thermodynamics,molecular architecture,applications,and phase states in past *** ahead,solving the way molecular architecture spreads to macro-functionality,that is,establishing the relationship between molecular architecture–dynamics–application,will catalyze novel advancements in PPCC research within the field of foods and biomaterials.

关键词： dynamics encapsulation liquid coacervate protein-polysaccharide complex coacervation solid precipitate

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