The emergence of precision electronic devices and wearable electronic products urgently requires high-performance multifunctional electromagnetic wave(EMW)absorbers to meet the applicability and versatility in various...The emergence of precision electronic devices and wearable electronic products urgently requires high-performance multifunctional electromagnetic wave(EMW)absorbers to meet the applicability and versatility in various applications.Herein,a dual-network(DN)gel was successfully prepared using acrylamide and sodium lignosulphonate as the basic units by simple chemical cross-linking and physical cross-linking methods.Specifically,the hydrogel forms two types of cross-linking networks through metal coordination and hydrogen bonding.Benefiting from the combined effects of dipole polarization and conductivity loss,the gel achieves an effective absorption bandwidth(EAB)of 6.74 GHz at a thickness of only 1.89 mm,demonstrating excellent EMW absorption performance.In addition,this unique structural configuration endows the EMW absorber with multifunctional features,such as remarkable tensile strength,good environmental compatibility,ultraviolet(UV)resistance,and excellent adhesion.Integrating multiple functional features into the EMW gels displays a broad application prospect in a variety of application scenarios.This research reveals the significance of DN structure design in the electromagnetic wave absorption(EWA)performance of gel-based materials,providing a substantial foundation for the multifunctional design of gel-based absorbers.展开更多
The year 2026 marks the 70th anniversary of the establishment of diplomatic relations between China and African countries.It also marks the launch of the China-Africa Year of People-to-People Exchanges.At this pivotal...The year 2026 marks the 70th anniversary of the establishment of diplomatic relations between China and African countries.It also marks the launch of the China-Africa Year of People-to-People Exchanges.At this pivotal juncture linking past achievements with future development,Wang Yi,member of the Political Bureau of the Communist Party of China Central Committee and foreign minister,continued the longstanding diplomatic tradition under which the Chinese foreign minister makes Africa the destination of the first overseas visit of the year,a practice upheld for 36 consecutive years,underscoring the stability,continuity and sincerity of China’s policy towards Africa.展开更多
Presently,financial portfolio managers lack a solid basis for building a reliable risk management strategy for green debt instrument investments due to the lack of compelling growth and resilience data.Therefore,this ...Presently,financial portfolio managers lack a solid basis for building a reliable risk management strategy for green debt instrument investments due to the lack of compelling growth and resilience data.Therefore,this study assesses the role of green bonds in financial markets by assessing and correlating their complex scaling behaviors across multiple periods with those of key benchmark assets(e.g.,conventional bonds,high-yield bonds,Euro-Dollar exchange,Dow Jones Industrial Index,Bitcoin,and Gold).Specifically,we explore linear and nonlinear correlation patterns using crosscorrelation tests and the dynamic conditional correlation model,focusing on bond interactions under various degrees of freedom.Our analysis reveals that although most assets exhibit nonlinear correlations,Bitcoin uniquely aligns linearly with U.S.bonds under certain conditions.Green bonds,however,display nonlinear correlations with Bitcoin and stand out for their distinct upward financial persistence.We find also that green bonds are primary drivers in the financial domain,highlighted by their pronounced interactions and the consistent cross-correlation with the Euro-Dollar exchange rate.Moreover,green bonds have the lowest multifractality,showing persistent upward trends and antipersistent downward trends,rendering them quite resilient during periods of high volatility.These results imply that green bonds may be advantageous to portfolio risk management strategies,especially during crises when diversification and hedging tactics are needed.展开更多
Quantifying the hydrogen bond(H-bond)strength of polymers is essential for rational design of advanced materials.However,direct measurement remains challenging because of the structural complexity of polymers and the ...Quantifying the hydrogen bond(H-bond)strength of polymers is essential for rational design of advanced materials.However,direct measurement remains challenging because of the structural complexity of polymers and the weak nature of H-bonds.Vacuum-based singlemolecule force spectroscopy(Vac-SMFS)offers a new and precise approach for such measurements.Using polyallylamine(PAAm)as a model polymer,the intrinsic strength(i.e.,strength without external influences)of representative N―H…N H-bonds was quantified to be about 5.25 kJ·mol^(–1).Comparative Vac-SMFS analysis across different polymer systems revealed that the N―H…N H-bonds in PAAm are unexpectedly stronger than the N―H…O H-bonds in poly(N-isopropylacrylamide)(PNIPAM)and the O―H…O H-bonds in poly(hydroxyethyl methacrylate)(PHEMA).This trend contrasts with that of established small-molecule systems.These results highlight how side-chain length and spatial configuration dictate polymer H-bond strengths,expanding the fundamental knowledge of polymer interactions and enabling the rational design of next-generation functional materials.展开更多
Effective treatment of subcutaneous tumors remains a focal point in cancer therapy.Photothermal therapy,a novel therapeutic approach,has emerged as a promising alternative,offering a less invasive option for the treat...Effective treatment of subcutaneous tumors remains a focal point in cancer therapy.Photothermal therapy,a novel therapeutic approach,has emerged as a promising alternative,offering a less invasive option for the treatment of subcutaneous tumors.This study reports the exploration of novel supramolecular halogen-bonded organic frameworks(XOFs)based on[N…Br^(+)…N]halogen bonds through the ligand exchange strategy and their application in photothermal therapy.Through ligand exchange,XOF(Br)-TPy was successfully prepared,and its structure and properties were thoroughly characterized using NMR,XPS,FT-IR,and XRD techniques.Due to their cationic characteristics,these XOFs serve as effective carriers for the photothermal agent IR820.In vitro experiments demonstrated that the IR820@XOF(Br)-TPy composite exhibits excellent photothermal conversion efficiency under NIR irradiation,effectively inducing tumor cell ablation.Furthermore,in vivo studies confirmed the remarkable antitumor efficacy of the composite material in a subcutaneous tumor model.This work demonstrates that the ligand exchange strategy is a versatile and facile approach for constructing XOFs(Br)and provides a novel strategy for developing advanced photothermal therapeutic agents with significant application potential.展开更多
Mn-based layered oxides(KMO)have emerged as one of the promising low-cost cathodes for potassiumion batteries(PIBs).However,due to the multiple-phase transitions and the distortion in the MnO6structure induced by the ...Mn-based layered oxides(KMO)have emerged as one of the promising low-cost cathodes for potassiumion batteries(PIBs).However,due to the multiple-phase transitions and the distortion in the MnO6structure induced by the Jahn-Teller(JT)effect associated with Mn-ion,the cathode exhibits poor structural stability.Herein,we propose a strategy to enhance structural stability by introducing robust metal-oxygen(M-O)bonds,which can realize the pinning effect to constrain the distortion in the transition metal(TM)layer.Concurrently,all the elements employed have exceptionally high crustal abundance.As a proof of concept,the designed K_(0.5)Mn_(0.9)Mg_(0.025)Ti_(0.025)Al_(0.05)O_(2)cathode exhibited a discharge capacity of approximately 100 mA h g^(-1)at 20 mA g^(-1)with 79%capacity retention over 50 cycles,and 73%capacity retention over 200 cycles at 200 mA g^(-1),showcased much better battery performance than the designed cathode with less robust M-O bonds.The properties of the formed M-O bonds were investigated using theoretical calculations.The enhanced dynamics,mitigated JT effect,and improved structural stability were elucidated through the in-situ X-ray diffractometer(XRD),in-situ electrochemical impedance spectroscopy(EIS)(and distribution of relaxation times(DRT)method),and ex-situ X-ray absorption fine structure(XAFS)tests.This study holds substantial reference value for the future design of costeffective Mn-based layered cathodes for PIBs.展开更多
Organofluorines play a crucial role in medicine,agrochemicals,and materials science.Adding fluorine to molecules creates structures with specific beneficial properties or tunes properties through interactions with the...Organofluorines play a crucial role in medicine,agrochemicals,and materials science.Adding fluorine to molecules creates structures with specific beneficial properties or tunes properties through interactions with their environment.Many popular pharmaceuticals and agrochemicals contain fluorine because it enhances hydrogen bonding at protein’s active sites.展开更多
1 As autumn becomes winter,I eagerly anticipate December's reunion with my older brother,Don,at SilverStar Mountain Resort.Our annual“SilverStar time”has reconnected us over the past decade,filling me with excit...1 As autumn becomes winter,I eagerly anticipate December's reunion with my older brother,Don,at SilverStar Mountain Resort.Our annual“SilverStar time”has reconnected us over the past decade,filling me with excitement and reflection.展开更多
The advancement of functional adhesives featuring recyclable and repairable properties is of great significance in interfacial science and engineering.Herein,a series of high-strength,recyclable fluorine-containing ad...The advancement of functional adhesives featuring recyclable and repairable properties is of great significance in interfacial science and engineering.Herein,a series of high-strength,recyclable fluorine-containing adhesives(ESOx-FPF)were designed and synthesized by crosslinking two prepolymers,FPF-B(derived from side-chain fluorinated diol,isocyanate,and aminoboric acid)and ESO-B(synthesized from biobased epoxy soybean oil and aminoboric acid),through dynamic boro-oxygen bonds.The resulting adhesive exhibited an optimal tensile strength of 42 MPa and the shear strength on steel plates reached as high as 3.89 MPa.More importantly,benefiting from the dynamic reversibility of the boron-oxygen bonds along with the hydrogen bonds interaction,ESOx-FPF can be welded with the assistance of solvents and recycled for multiple cycles.The outstanding healing efficiency and excellent reprocessability of these functional adhesives were confirmed by mechanical testing.Moreover,the as-prepared adhesives demonstrated universal and remarkable adhesion to various substrates,such as aromatic polyamide,aluminum plates and polycarbonate,meanwhile,they could be easily disassembled and recycled using ethanol without damaging the substrates surface.This study not only provides a simple strategy for the synthesis of eco-friendly adhesives with weldable and recyclable properties,but also sheds light on the development of other functional materials utilizing dynamic covalent chemistry.展开更多
The selective addition reaction of unsaturated C-C bonds has always been a classic and constant research topic.Different from well-developed hydroboration,hydrosilylation,and hydrostannylation reaction,hydrogermylatio...The selective addition reaction of unsaturated C-C bonds has always been a classic and constant research topic.Different from well-developed hydroboration,hydrosilylation,and hydrostannylation reaction,hydrogermylation reaction remains challenging which hasn't been much reported.Herein,we developed a new metal-porous ligand polymers Pd1@POL-PPh_(n)Cy_(m)(n+m=3)with monoatomic dispersion characteristics for highly selective and efficient hydrogermylation of unsaturated C-C bonds,including alkynes,alkenes,and allenes.X-ray photoelectron spectroscopy and theoretical calculations further proved the introduction of cyclohexyl could gently adjust the charge on monoatomic Pd center which effectively facilitate the recognition and transformation of various substrates.With the electrically fine-tuned single atom palladium catalysts,we realized theα-germanium addition for the first time,obtaining corresponding allyl germanium and alkyl germanium compounds.展开更多
Intrinsically stretchable semiconducting polymers play a vital role in the development of wearable electronics,featuring low-cost,large-area and high-density fabrication.Only single-stage dynamic chemical bond has bee...Intrinsically stretchable semiconducting polymers play a vital role in the development of wearable electronics,featuring low-cost,large-area and high-density fabrication.Only single-stage dynamic chemical bond has been widely incorporated into polymer backbones to afford stretchability while multiple dynamic bonds have not been investigated,making a formidable challenge to achieve high stretchability without compromising charge transport properties.Herein,we synthesize a series of stretchable polymer semiconductors incorporating urethane and bipyridine units,which can provide dynamic interconnected polymer network by combination of hydrogen bonds with metal coordination,simultaneously obtaining excellent stretchability and carrier mobilities.Compared with single-stage hydrogen bonds,multiple dynamic chemical bonds constructed by 10% hydrogen bonds and 0.25 equiv.metal coordination endowed the polymer semiconductors with an 58% enhancement in carrier mobility and a two-fold increase in crack-onset strain.Notably,the polymer exhibited stable carrier mobilities parallel to the stretching direction,with 91% of initial values even under 150% strain,which is the unprecedented value for intrinsically stretchable semiconducting polymers without blending of elastomers.Therefore,the introduction of multiple dynamic bonds provides an effective and promising approach for intrinsically stretchable and high-performance polymer semiconductor.展开更多
Low-cost and large-area uniform amorphous Ga_(2)O_(3)(α-Ga_(2)O_(3))solar-blind ultraviolet(UV)detectors have garnered significant attention in recent years.Oxygen vacancy(VO)defects are generally considered as the p...Low-cost and large-area uniform amorphous Ga_(2)O_(3)(α-Ga_(2)O_(3))solar-blind ultraviolet(UV)detectors have garnered significant attention in recent years.Oxygen vacancy(VO)defects are generally considered as the predominant defects affecting the detector performance.Reducing VOconcentration generally results in both low dark current and low photo current,significantly limiting further improvement of the photo-to-dark current ratio(PDCR)parameter.Herein,a delicately optimized atomic layer deposition(ALD)method is revealed having the capability to break through the trade-off in a-Ga_(2)O_(3),achieving both low dark current and high photocurrent simultaneously.For a clear demonstration,a-Ga_(2)O_(3)contrast sample is prepared by magnetron sputtering and compared as well.Combined tests are performed including xray photoelectron spectroscopy,photoluminescence,electron paramagnetic resonance and Fourier-transform infrared spectroscopy.It is found that ALDα-Ga_(2)O_(3)has a lower VOconcentration,but also a lower dangling bonds concentration which are strong non-irradiation recombination centers.Therefore,decrease of dangling bonds is suggested to compensate for the low optical gain induced by low VOconcentration and promote the PDCR to~2.06×10^(6).Our findings firstly prove that the dangling bonds also play an important role in determining the a-Ga_(2)O_(3)detection performance,offering new insights for further promotion ofα-Ga_(2)O_(3)UV detector performance via dual optimization of dangling bonds and VO.展开更多
With the support of the Belt and Road Initiative(BRI),the international reach of traditional Chinese medicine(TCM)is taking shape as a“Silk Road of Health,”opening new pathways for closer connections among peoples.T...With the support of the Belt and Road Initiative(BRI),the international reach of traditional Chinese medicine(TCM)is taking shape as a“Silk Road of Health,”opening new pathways for closer connections among peoples.The journey of TCM,in turn.展开更多
Green bonds, as one of the core tools of green finance, have rapidly developed into a large-scale and far-reaching financial market since the first green bond was issued in 2007. As a direct financing channel for gree...Green bonds, as one of the core tools of green finance, have rapidly developed into a large-scale and far-reaching financial market since the first green bond was issued in 2007. As a direct financing channel for green projects, green bonds have promoted the rapid development of green finance in China, and under the background of “dual carbon”, the demand for green bonds in China has increased significantly. In fact, the Chinese green bond investment market has vast development space. However, due to its late start and immature development, there are doubts about whether green bonds can play a positive role in enhancing the company’s value. Therefore, it is urgent to conduct in-depth analysis of the impact of the company’s issuance of green bonds on its value. In this paper, we used Tobin’s Q to measure company value, and used panel data to explore the impact of issuing green bonds on company value through propensity score matching method. It explored the significant improvement effect of issuing green bonds and increasing their intensity on company value;and then, by analyzing the mediating effect on the impact mechanism of company value, efforts are made to discover that green bonds can enhance company value by alleviating financing constraints and improving information transparency. Finally, based on the conclusions drawn, reasonable suggestions are proposed, which have practical reference value for the development of the green bond market and the construction of a green financial system.展开更多
Constructing multi-dimensional hydrogen bond(H-bond)regulated single-molecule systems with multiemission remains a challenge.Herein,we report the design of a new excited-state intramolecular proton transfer(ESIPT)feat...Constructing multi-dimensional hydrogen bond(H-bond)regulated single-molecule systems with multiemission remains a challenge.Herein,we report the design of a new excited-state intramolecular proton transfer(ESIPT)featured chromophore(HBT-DPI)that shows flexible emission tunability via the multidimensional regulation of intra-and intermolecular H-bonds.The feature of switchable intramolecular Hbonds is induced via incorporating several hydrogen bond acceptors and donors into one single HBT-DPI molecule,allowing the“turn on/off”of ESIPT process by forming isomers with distinct intramolecular Hbonds configurations.In response to different external H-bonding environments,the obtained four types of crystal/cocrystals vary in the contents of isomers and the molecular packing modes,which are mainly guided by the intermolecular H-bonds,exhibiting non-emissive features or emissions ranging from green to orange.Utilizing the feature of intermolecular H-bond guided molecular packing,we demonstrate the utility of this fluorescent material for visualizing hydrophobic/hydrophilic areas on large-scale heterogeneous surfaces of modified poly(1,1-difluoroethylene)(PVDF)membranes and quantitatively estimating the surface hydrophobicity,providing a new approach for hydrophobicity/hydrophilicity monitoring and measurement.Overall,this study represents a new design strategy for constructing multi-dimensional hydrogen bond regulated ESIPT-based fluorescent materials that enable multiple emissions and unique applications.展开更多
AI-driven fintech industries face critical vulnerabilities from volatile rare earth and metallic mineral prices,geopolitical instability,and inflationary pressures.Sovereign inflation-linked bonds serve as incentives ...AI-driven fintech industries face critical vulnerabilities from volatile rare earth and metallic mineral prices,geopolitical instability,and inflationary pressures.Sovereign inflation-linked bonds serve as incentives for investors in technological industries,despite the risks associated with rising costs of goods.By analyzing global data(8 September 2020–9 September 2023)via cross-quantilogram,recursive cross-quantilogram and quantile vector autoregressive approaches,this study reveals how Russia–Ukraine geopolitical risk,sovereign inflation–linked bonds,rare earth and metallic mineral prices disrupt AI-driven fintech outputs.Key findings indicate that rising rare earth prices suppress fintech productivity in long-term growth periods,whereas sovereign inflation-linked bonds mitigate short-term inflationary risk.Geopolitical turmoil disproportionately harms fintech outputs during market downturns,with both mineral price volatility and conflict-driven shocks amplifying systemic instability in fintech outputs and sovereign inflation-linked bonds.These results urge policymakers to secure critical mineral supply chains,promote inflation-hedging financial instruments,and foster international cooperation to buffer AI-driven fintech sectors against geopolitical and resource-driven disruptions.展开更多
Launched in December 2021,the China-Laos Railway(CLR)has created ample opportunities for the development of Laos’crop production,food processing,and manufacturing.A powerful booster to infrastructure connectivity and...Launched in December 2021,the China-Laos Railway(CLR)has created ample opportunities for the development of Laos’crop production,food processing,and manufacturing.A powerful booster to infrastructure connectivity and trade relations between the two countries,the rail project has also opened a door for young people in Laos through vocational training and education cooperation,strengthening the bonds of friendship between the two peoples.展开更多
The intrinsic symmetrical electron distribution in crystalline metal sulfides usually causes an improper electronic configuration between catalytic S atoms and H intermediates(H_(ad))to form strong S-H_(ad) bonds,resu...The intrinsic symmetrical electron distribution in crystalline metal sulfides usually causes an improper electronic configuration between catalytic S atoms and H intermediates(H_(ad))to form strong S-H_(ad) bonds,resulting in a low photocatalytic H_(2) evolution activity.Herein,a cobalt-induced asymmetric electronic distribution is justified as an effective strategy to optimize the electronic configuration of catalytic S sites in NiCoS cocatalysts for highly active photocatalytic H_(2) evolution.To this end,Co atoms are uniformly incorporated in NiS nanoparticles to fabricate homogeneous NiCoS cocatalyst on TiO_(2) surface by a facile photosynthesis strategy.It is revealed that the incorporated Co atoms break the electron distribution symmetry in NiS,thus essentially increasing the electron density of S atoms to form active electron-enriched S^(2+δ)–sites.The electron-enriched S^(2+δ)–sites could interact with Had via an increased antibonding orbital occupancy,which weakens S–Had bonds for efficient H_(ad) adsorption and desorption,endowing the NiCoS cocatalysts with a highly active H_(2) evolution process.Consequently,the optimized NiCoS/TiO_(2)(1:2)photocatalyst displays the highest H_(2) production performance,outperforming the NiS/TiO_(2) and CoS/TiO_(2) samples by factors of 2.1 and 2.5,respectively.This work provides novel insights on breaking electron distribution symmetry to optimize catalytic efficiency of active sites.展开更多
This study analyzes the influence of green bonds on carbon neutrality.It examines the daily data of sectoral CO_(2) emissions of the top five CO_(2)-emitting nations from January 2,2019 to December 30,2022 using wavel...This study analyzes the influence of green bonds on carbon neutrality.It examines the daily data of sectoral CO_(2) emissions of the top five CO_(2)-emitting nations from January 2,2019 to December 30,2022 using wavelet transform coherence,quantile-onquantile regression,Granger causality in quantiles,and quantile regression approaches.The results revealed that(i)green bonds are strongly related to sectoral CO_(2) emissions;(ii)green bonds reduce transport sector CO_(2) emissions in China,the US,and Japan while causing an upsurge in India and Russia;(iii)green bonds reduce industrial sector CO_(2) emissions only in the US;(iv)green bonds have a declining influence in energy sector CO_(2) emissions at lower quantiles in India,China,and the US,whereas the impact increases at higher quantiles;and(v)green bonds decrease residential sector CO_(2) emissions in the US,Russia,and Japan.The study revealed that green bonds help reduce CO_(2) emissions in the residential sector in various quantiles.Therefore,the US,Russia,and Japan should raise household awareness of green energy utilization by promoting them with green bonds.In addition,green bonds can effectively reduce transportation sector CO_(2) emissions in China and the US.Therefore,the policymakers of the two global powers should contribute to global CO_(2) reduction by promoting green transportation and clean energy transition in the transportation sector through green bonds.Thus,green bonds can play an effective role in the fight against global warming.展开更多
Constructing heterojunction photocatalysts is a highly effective strategy for achieving overall water splitting,particularly by overcoming the challenge of sluggish electron-hole transport.This study employed a defect...Constructing heterojunction photocatalysts is a highly effective strategy for achieving overall water splitting,particularly by overcoming the challenge of sluggish electron-hole transport.This study employed a defect-induced in situ growth approach to anchor NiSe onto carbon-vacancy-rich C_(3)N_(5)(C_(v)-C_(3)N_(5)),forming interfacial Ni-N bonds.The resulting NiSe/C_(v)-C_(3)N_(5)heterojunction exhibited stoichiometric H_(2)and O_(2)evolution rates of 1956.1 and 989.1μmol g^(-1)h^(-1),respectively,8.4 times higher than a counterpart lacking interfacial bonding.Both theoretical calculations and experimental data confirmed that the Ni–N bonds were instrumental in enhancing photocatalytic performance by inducing and reinforcing S-scheme charge transfer.Illumination X-ray photoelectron spectroscopy analysis revealed that a synergistic charge transfer pathway:photoexcited electrons from the NiSe conduction band migrated sequentially to Ni atoms,then to N atoms,and ultimately recombined with holes in the C_(v)-C_(3)N_(5)valence band.Moreover,these interfacial bonds significantly lowered the energy barrier and shortened the transport distance for electron transfer,amplifying the built-in interfacial electric field and accelerating charge dynamics.This study provides critical insights into the rational design of heterojunction photocatalysts for efficient water splitting.展开更多
基金supported by the National Natural Science Foundation of China(Nos.52231007,51872238,52074227,and 21806129)the Fundamental Research Funds for the Central Universities(Nos.3102018zy045,3102019AX11,and 5000220455)the Natural Science Basic Research Plan in Shaanxi Province of China(Nos.2017JQ5116 and 2020JM-118).
文摘The emergence of precision electronic devices and wearable electronic products urgently requires high-performance multifunctional electromagnetic wave(EMW)absorbers to meet the applicability and versatility in various applications.Herein,a dual-network(DN)gel was successfully prepared using acrylamide and sodium lignosulphonate as the basic units by simple chemical cross-linking and physical cross-linking methods.Specifically,the hydrogel forms two types of cross-linking networks through metal coordination and hydrogen bonding.Benefiting from the combined effects of dipole polarization and conductivity loss,the gel achieves an effective absorption bandwidth(EAB)of 6.74 GHz at a thickness of only 1.89 mm,demonstrating excellent EMW absorption performance.In addition,this unique structural configuration endows the EMW absorber with multifunctional features,such as remarkable tensile strength,good environmental compatibility,ultraviolet(UV)resistance,and excellent adhesion.Integrating multiple functional features into the EMW gels displays a broad application prospect in a variety of application scenarios.This research reveals the significance of DN structure design in the electromagnetic wave absorption(EWA)performance of gel-based materials,providing a substantial foundation for the multifunctional design of gel-based absorbers.
文摘The year 2026 marks the 70th anniversary of the establishment of diplomatic relations between China and African countries.It also marks the launch of the China-Africa Year of People-to-People Exchanges.At this pivotal juncture linking past achievements with future development,Wang Yi,member of the Political Bureau of the Communist Party of China Central Committee and foreign minister,continued the longstanding diplomatic tradition under which the Chinese foreign minister makes Africa the destination of the first overseas visit of the year,a practice upheld for 36 consecutive years,underscoring the stability,continuity and sincerity of China’s policy towards Africa.
基金Benjamin M.Tabak(Grant no.305485/2022-9)gratefully acknowledges financial support from the CNPq foundation and CAPES Foundation。
文摘Presently,financial portfolio managers lack a solid basis for building a reliable risk management strategy for green debt instrument investments due to the lack of compelling growth and resilience data.Therefore,this study assesses the role of green bonds in financial markets by assessing and correlating their complex scaling behaviors across multiple periods with those of key benchmark assets(e.g.,conventional bonds,high-yield bonds,Euro-Dollar exchange,Dow Jones Industrial Index,Bitcoin,and Gold).Specifically,we explore linear and nonlinear correlation patterns using crosscorrelation tests and the dynamic conditional correlation model,focusing on bond interactions under various degrees of freedom.Our analysis reveals that although most assets exhibit nonlinear correlations,Bitcoin uniquely aligns linearly with U.S.bonds under certain conditions.Green bonds,however,display nonlinear correlations with Bitcoin and stand out for their distinct upward financial persistence.We find also that green bonds are primary drivers in the financial domain,highlighted by their pronounced interactions and the consistent cross-correlation with the Euro-Dollar exchange rate.Moreover,green bonds have the lowest multifractality,showing persistent upward trends and antipersistent downward trends,rendering them quite resilient during periods of high volatility.These results imply that green bonds may be advantageous to portfolio risk management strategies,especially during crises when diversification and hedging tactics are needed.
基金financially supported by the National Natural Science Foundation of China(No.22273079)Fundamental Research Funds for the Central Universities(No.2682025ZTPY004)。
文摘Quantifying the hydrogen bond(H-bond)strength of polymers is essential for rational design of advanced materials.However,direct measurement remains challenging because of the structural complexity of polymers and the weak nature of H-bonds.Vacuum-based singlemolecule force spectroscopy(Vac-SMFS)offers a new and precise approach for such measurements.Using polyallylamine(PAAm)as a model polymer,the intrinsic strength(i.e.,strength without external influences)of representative N―H…N H-bonds was quantified to be about 5.25 kJ·mol^(–1).Comparative Vac-SMFS analysis across different polymer systems revealed that the N―H…N H-bonds in PAAm are unexpectedly stronger than the N―H…O H-bonds in poly(N-isopropylacrylamide)(PNIPAM)and the O―H…O H-bonds in poly(hydroxyethyl methacrylate)(PHEMA).This trend contrasts with that of established small-molecule systems.These results highlight how side-chain length and spatial configuration dictate polymer H-bond strengths,expanding the fundamental knowledge of polymer interactions and enabling the rational design of next-generation functional materials.
基金supported by the National Natural Science Foundation of China(Nos.22371218,82271518,21801194)Xianyang Bureau of Science and Technology(No.L2024-QCY-ZYYJJQ-260)+2 种基金The Interdisciplinary Innovative Talents Foundation from Renmin Hospital of Wuhan University(No.JCRCFZ-2022-030)Guiding Projects of Traditional Chinese Medicine in 2023~2024 by Hubei Provincial Administration of Traditional Chinese Medicine(No.ZY2023F038)the support of the Core Facility of Wuhan University and the Large-scale Instrument and Equipment Sharing Foundation of Wuhan University。
文摘Effective treatment of subcutaneous tumors remains a focal point in cancer therapy.Photothermal therapy,a novel therapeutic approach,has emerged as a promising alternative,offering a less invasive option for the treatment of subcutaneous tumors.This study reports the exploration of novel supramolecular halogen-bonded organic frameworks(XOFs)based on[N…Br^(+)…N]halogen bonds through the ligand exchange strategy and their application in photothermal therapy.Through ligand exchange,XOF(Br)-TPy was successfully prepared,and its structure and properties were thoroughly characterized using NMR,XPS,FT-IR,and XRD techniques.Due to their cationic characteristics,these XOFs serve as effective carriers for the photothermal agent IR820.In vitro experiments demonstrated that the IR820@XOF(Br)-TPy composite exhibits excellent photothermal conversion efficiency under NIR irradiation,effectively inducing tumor cell ablation.Furthermore,in vivo studies confirmed the remarkable antitumor efficacy of the composite material in a subcutaneous tumor model.This work demonstrates that the ligand exchange strategy is a versatile and facile approach for constructing XOFs(Br)and provides a novel strategy for developing advanced photothermal therapeutic agents with significant application potential.
基金financially supported by the National Natural Science Foundation of China(NSFC)(52274295)the Natural Science Foundation of Hebei Province(E2021501029)+3 种基金the Fundamental Research Funds for the Central Universities(N2423051,N2423053,N2302016,N2423019,N2323013,N2423005)the Science and Technology Project of Hebei Education Department(QN2024238)the Basic Research Program Project of Shijiazhuang City for Universities Stationed in Hebei Province(241790937A)the Science and Technology Project of Qinhuangdao City in 2023.
文摘Mn-based layered oxides(KMO)have emerged as one of the promising low-cost cathodes for potassiumion batteries(PIBs).However,due to the multiple-phase transitions and the distortion in the MnO6structure induced by the Jahn-Teller(JT)effect associated with Mn-ion,the cathode exhibits poor structural stability.Herein,we propose a strategy to enhance structural stability by introducing robust metal-oxygen(M-O)bonds,which can realize the pinning effect to constrain the distortion in the transition metal(TM)layer.Concurrently,all the elements employed have exceptionally high crustal abundance.As a proof of concept,the designed K_(0.5)Mn_(0.9)Mg_(0.025)Ti_(0.025)Al_(0.05)O_(2)cathode exhibited a discharge capacity of approximately 100 mA h g^(-1)at 20 mA g^(-1)with 79%capacity retention over 50 cycles,and 73%capacity retention over 200 cycles at 200 mA g^(-1),showcased much better battery performance than the designed cathode with less robust M-O bonds.The properties of the formed M-O bonds were investigated using theoretical calculations.The enhanced dynamics,mitigated JT effect,and improved structural stability were elucidated through the in-situ X-ray diffractometer(XRD),in-situ electrochemical impedance spectroscopy(EIS)(and distribution of relaxation times(DRT)method),and ex-situ X-ray absorption fine structure(XAFS)tests.This study holds substantial reference value for the future design of costeffective Mn-based layered cathodes for PIBs.
文摘Organofluorines play a crucial role in medicine,agrochemicals,and materials science.Adding fluorine to molecules creates structures with specific beneficial properties or tunes properties through interactions with their environment.Many popular pharmaceuticals and agrochemicals contain fluorine because it enhances hydrogen bonding at protein’s active sites.
文摘1 As autumn becomes winter,I eagerly anticipate December's reunion with my older brother,Don,at SilverStar Mountain Resort.Our annual“SilverStar time”has reconnected us over the past decade,filling me with excitement and reflection.
基金financially supported by the Natural Science Foundation of Shandong Province(No.ZR2022MB034)。
文摘The advancement of functional adhesives featuring recyclable and repairable properties is of great significance in interfacial science and engineering.Herein,a series of high-strength,recyclable fluorine-containing adhesives(ESOx-FPF)were designed and synthesized by crosslinking two prepolymers,FPF-B(derived from side-chain fluorinated diol,isocyanate,and aminoboric acid)and ESO-B(synthesized from biobased epoxy soybean oil and aminoboric acid),through dynamic boro-oxygen bonds.The resulting adhesive exhibited an optimal tensile strength of 42 MPa and the shear strength on steel plates reached as high as 3.89 MPa.More importantly,benefiting from the dynamic reversibility of the boron-oxygen bonds along with the hydrogen bonds interaction,ESOx-FPF can be welded with the assistance of solvents and recycled for multiple cycles.The outstanding healing efficiency and excellent reprocessability of these functional adhesives were confirmed by mechanical testing.Moreover,the as-prepared adhesives demonstrated universal and remarkable adhesion to various substrates,such as aromatic polyamide,aluminum plates and polycarbonate,meanwhile,they could be easily disassembled and recycled using ethanol without damaging the substrates surface.This study not only provides a simple strategy for the synthesis of eco-friendly adhesives with weldable and recyclable properties,but also sheds light on the development of other functional materials utilizing dynamic covalent chemistry.
基金supported by the National Natural Science Foundation of China(Nos.22201049,22471046)the Ba-Gui Youth Top-notch Talents Project of Guangxithe National HighLevel Personnel of Special Support Program for Young Top-notch Talents(9th batch)。
文摘The selective addition reaction of unsaturated C-C bonds has always been a classic and constant research topic.Different from well-developed hydroboration,hydrosilylation,and hydrostannylation reaction,hydrogermylation reaction remains challenging which hasn't been much reported.Herein,we developed a new metal-porous ligand polymers Pd1@POL-PPh_(n)Cy_(m)(n+m=3)with monoatomic dispersion characteristics for highly selective and efficient hydrogermylation of unsaturated C-C bonds,including alkynes,alkenes,and allenes.X-ray photoelectron spectroscopy and theoretical calculations further proved the introduction of cyclohexyl could gently adjust the charge on monoatomic Pd center which effectively facilitate the recognition and transformation of various substrates.With the electrically fine-tuned single atom palladium catalysts,we realized theα-germanium addition for the first time,obtaining corresponding allyl germanium and alkyl germanium compounds.
基金the Fundamental Research Funds for the Central Universities(No.buctrc202103)the National Natural Science Foundation of China(Nos.52373170,22171019)+1 种基金Beijing Natural Science Foundation(No.2252015),SINOPEC(No.225057)Open Project Program of the State Key Laboratory of Fine Chemicals(No.KF2201,Dalian University of Technology)。
文摘Intrinsically stretchable semiconducting polymers play a vital role in the development of wearable electronics,featuring low-cost,large-area and high-density fabrication.Only single-stage dynamic chemical bond has been widely incorporated into polymer backbones to afford stretchability while multiple dynamic bonds have not been investigated,making a formidable challenge to achieve high stretchability without compromising charge transport properties.Herein,we synthesize a series of stretchable polymer semiconductors incorporating urethane and bipyridine units,which can provide dynamic interconnected polymer network by combination of hydrogen bonds with metal coordination,simultaneously obtaining excellent stretchability and carrier mobilities.Compared with single-stage hydrogen bonds,multiple dynamic chemical bonds constructed by 10% hydrogen bonds and 0.25 equiv.metal coordination endowed the polymer semiconductors with an 58% enhancement in carrier mobility and a two-fold increase in crack-onset strain.Notably,the polymer exhibited stable carrier mobilities parallel to the stretching direction,with 91% of initial values even under 150% strain,which is the unprecedented value for intrinsically stretchable semiconducting polymers without blending of elastomers.Therefore,the introduction of multiple dynamic bonds provides an effective and promising approach for intrinsically stretchable and high-performance polymer semiconductor.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.62404146,12174275,62174113)the Basic and Applied Basic Research Foundation of Guangdong Province,China(Grant Nos.2023A1515110730 and 2023A1515140094)the INTPART Program at the Research Council of Norway(Project number 322382)。
文摘Low-cost and large-area uniform amorphous Ga_(2)O_(3)(α-Ga_(2)O_(3))solar-blind ultraviolet(UV)detectors have garnered significant attention in recent years.Oxygen vacancy(VO)defects are generally considered as the predominant defects affecting the detector performance.Reducing VOconcentration generally results in both low dark current and low photo current,significantly limiting further improvement of the photo-to-dark current ratio(PDCR)parameter.Herein,a delicately optimized atomic layer deposition(ALD)method is revealed having the capability to break through the trade-off in a-Ga_(2)O_(3),achieving both low dark current and high photocurrent simultaneously.For a clear demonstration,a-Ga_(2)O_(3)contrast sample is prepared by magnetron sputtering and compared as well.Combined tests are performed including xray photoelectron spectroscopy,photoluminescence,electron paramagnetic resonance and Fourier-transform infrared spectroscopy.It is found that ALDα-Ga_(2)O_(3)has a lower VOconcentration,but also a lower dangling bonds concentration which are strong non-irradiation recombination centers.Therefore,decrease of dangling bonds is suggested to compensate for the low optical gain induced by low VOconcentration and promote the PDCR to~2.06×10^(6).Our findings firstly prove that the dangling bonds also play an important role in determining the a-Ga_(2)O_(3)detection performance,offering new insights for further promotion ofα-Ga_(2)O_(3)UV detector performance via dual optimization of dangling bonds and VO.
文摘With the support of the Belt and Road Initiative(BRI),the international reach of traditional Chinese medicine(TCM)is taking shape as a“Silk Road of Health,”opening new pathways for closer connections among peoples.The journey of TCM,in turn.
文摘Green bonds, as one of the core tools of green finance, have rapidly developed into a large-scale and far-reaching financial market since the first green bond was issued in 2007. As a direct financing channel for green projects, green bonds have promoted the rapid development of green finance in China, and under the background of “dual carbon”, the demand for green bonds in China has increased significantly. In fact, the Chinese green bond investment market has vast development space. However, due to its late start and immature development, there are doubts about whether green bonds can play a positive role in enhancing the company’s value. Therefore, it is urgent to conduct in-depth analysis of the impact of the company’s issuance of green bonds on its value. In this paper, we used Tobin’s Q to measure company value, and used panel data to explore the impact of issuing green bonds on company value through propensity score matching method. It explored the significant improvement effect of issuing green bonds and increasing their intensity on company value;and then, by analyzing the mediating effect on the impact mechanism of company value, efforts are made to discover that green bonds can enhance company value by alleviating financing constraints and improving information transparency. Finally, based on the conclusions drawn, reasonable suggestions are proposed, which have practical reference value for the development of the green bond market and the construction of a green financial system.
基金supported by the National Key R&D Program of China(No.2021YFC2103600)the National Natural Science Foundation of China(Nos.21878156,21978131,22275085,and 22278224)+2 种基金the Natural Science Foundation of Jiangsu Province(Nos.BK20200089 and BK20200691)the Project of Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)the State Key Laboratory of Materials-Oriented Chemical Engineering(No.KL21-08).
文摘Constructing multi-dimensional hydrogen bond(H-bond)regulated single-molecule systems with multiemission remains a challenge.Herein,we report the design of a new excited-state intramolecular proton transfer(ESIPT)featured chromophore(HBT-DPI)that shows flexible emission tunability via the multidimensional regulation of intra-and intermolecular H-bonds.The feature of switchable intramolecular Hbonds is induced via incorporating several hydrogen bond acceptors and donors into one single HBT-DPI molecule,allowing the“turn on/off”of ESIPT process by forming isomers with distinct intramolecular Hbonds configurations.In response to different external H-bonding environments,the obtained four types of crystal/cocrystals vary in the contents of isomers and the molecular packing modes,which are mainly guided by the intermolecular H-bonds,exhibiting non-emissive features or emissions ranging from green to orange.Utilizing the feature of intermolecular H-bond guided molecular packing,we demonstrate the utility of this fluorescent material for visualizing hydrophobic/hydrophilic areas on large-scale heterogeneous surfaces of modified poly(1,1-difluoroethylene)(PVDF)membranes and quantitatively estimating the surface hydrophobicity,providing a new approach for hydrophobicity/hydrophilicity monitoring and measurement.Overall,this study represents a new design strategy for constructing multi-dimensional hydrogen bond regulated ESIPT-based fluorescent materials that enable multiple emissions and unique applications.
基金supported by the grant of the Russian Science Foundation(RSF Code:23-18-01065).
文摘AI-driven fintech industries face critical vulnerabilities from volatile rare earth and metallic mineral prices,geopolitical instability,and inflationary pressures.Sovereign inflation-linked bonds serve as incentives for investors in technological industries,despite the risks associated with rising costs of goods.By analyzing global data(8 September 2020–9 September 2023)via cross-quantilogram,recursive cross-quantilogram and quantile vector autoregressive approaches,this study reveals how Russia–Ukraine geopolitical risk,sovereign inflation–linked bonds,rare earth and metallic mineral prices disrupt AI-driven fintech outputs.Key findings indicate that rising rare earth prices suppress fintech productivity in long-term growth periods,whereas sovereign inflation-linked bonds mitigate short-term inflationary risk.Geopolitical turmoil disproportionately harms fintech outputs during market downturns,with both mineral price volatility and conflict-driven shocks amplifying systemic instability in fintech outputs and sovereign inflation-linked bonds.These results urge policymakers to secure critical mineral supply chains,promote inflation-hedging financial instruments,and foster international cooperation to buffer AI-driven fintech sectors against geopolitical and resource-driven disruptions.
文摘Launched in December 2021,the China-Laos Railway(CLR)has created ample opportunities for the development of Laos’crop production,food processing,and manufacturing.A powerful booster to infrastructure connectivity and trade relations between the two countries,the rail project has also opened a door for young people in Laos through vocational training and education cooperation,strengthening the bonds of friendship between the two peoples.
文摘The intrinsic symmetrical electron distribution in crystalline metal sulfides usually causes an improper electronic configuration between catalytic S atoms and H intermediates(H_(ad))to form strong S-H_(ad) bonds,resulting in a low photocatalytic H_(2) evolution activity.Herein,a cobalt-induced asymmetric electronic distribution is justified as an effective strategy to optimize the electronic configuration of catalytic S sites in NiCoS cocatalysts for highly active photocatalytic H_(2) evolution.To this end,Co atoms are uniformly incorporated in NiS nanoparticles to fabricate homogeneous NiCoS cocatalyst on TiO_(2) surface by a facile photosynthesis strategy.It is revealed that the incorporated Co atoms break the electron distribution symmetry in NiS,thus essentially increasing the electron density of S atoms to form active electron-enriched S^(2+δ)–sites.The electron-enriched S^(2+δ)–sites could interact with Had via an increased antibonding orbital occupancy,which weakens S–Had bonds for efficient H_(ad) adsorption and desorption,endowing the NiCoS cocatalysts with a highly active H_(2) evolution process.Consequently,the optimized NiCoS/TiO_(2)(1:2)photocatalyst displays the highest H_(2) production performance,outperforming the NiS/TiO_(2) and CoS/TiO_(2) samples by factors of 2.1 and 2.5,respectively.This work provides novel insights on breaking electron distribution symmetry to optimize catalytic efficiency of active sites.
文摘This study analyzes the influence of green bonds on carbon neutrality.It examines the daily data of sectoral CO_(2) emissions of the top five CO_(2)-emitting nations from January 2,2019 to December 30,2022 using wavelet transform coherence,quantile-onquantile regression,Granger causality in quantiles,and quantile regression approaches.The results revealed that(i)green bonds are strongly related to sectoral CO_(2) emissions;(ii)green bonds reduce transport sector CO_(2) emissions in China,the US,and Japan while causing an upsurge in India and Russia;(iii)green bonds reduce industrial sector CO_(2) emissions only in the US;(iv)green bonds have a declining influence in energy sector CO_(2) emissions at lower quantiles in India,China,and the US,whereas the impact increases at higher quantiles;and(v)green bonds decrease residential sector CO_(2) emissions in the US,Russia,and Japan.The study revealed that green bonds help reduce CO_(2) emissions in the residential sector in various quantiles.Therefore,the US,Russia,and Japan should raise household awareness of green energy utilization by promoting them with green bonds.In addition,green bonds can effectively reduce transportation sector CO_(2) emissions in China and the US.Therefore,the policymakers of the two global powers should contribute to global CO_(2) reduction by promoting green transportation and clean energy transition in the transportation sector through green bonds.Thus,green bonds can play an effective role in the fight against global warming.
文摘Constructing heterojunction photocatalysts is a highly effective strategy for achieving overall water splitting,particularly by overcoming the challenge of sluggish electron-hole transport.This study employed a defect-induced in situ growth approach to anchor NiSe onto carbon-vacancy-rich C_(3)N_(5)(C_(v)-C_(3)N_(5)),forming interfacial Ni-N bonds.The resulting NiSe/C_(v)-C_(3)N_(5)heterojunction exhibited stoichiometric H_(2)and O_(2)evolution rates of 1956.1 and 989.1μmol g^(-1)h^(-1),respectively,8.4 times higher than a counterpart lacking interfacial bonding.Both theoretical calculations and experimental data confirmed that the Ni–N bonds were instrumental in enhancing photocatalytic performance by inducing and reinforcing S-scheme charge transfer.Illumination X-ray photoelectron spectroscopy analysis revealed that a synergistic charge transfer pathway:photoexcited electrons from the NiSe conduction band migrated sequentially to Ni atoms,then to N atoms,and ultimately recombined with holes in the C_(v)-C_(3)N_(5)valence band.Moreover,these interfacial bonds significantly lowered the energy barrier and shortened the transport distance for electron transfer,amplifying the built-in interfacial electric field and accelerating charge dynamics.This study provides critical insights into the rational design of heterojunction photocatalysts for efficient water splitting.
