Herein we wish to propose the concept of"element-transfer reaction",which may afford the access to elemental compounds by transferring certain elements from easily available resources efficiently,concisely a...Herein we wish to propose the concept of"element-transfer reaction",which may afford the access to elemental compounds by transferring certain elements from easily available resources efficiently,concisely and precisely.A good element-transfer reaction with industrial application potential shall not generate waste and is performed under energy-saving and environment-friendly conditions.During the past decade,we have developed a series of methods for the synthesis of fluorine-and seleniumcontaining compounds via the fluorine-and selenium-transfer reactions,while the redox reactions we re considered to be the oxygen-and hydrogen-transfer reactions as well and were also widely studied by our group for producing the high-value-added fine chemicals.Some of these technologies have been successfully industrialized.This review summarizes our staged research results on fluorine-,oxygen-,hydrogen-and selenium-transfer reactions and makes a prospect on the developing trend in the field.展开更多
Sodium metal batteries(SMBs)have attracted increasing attention over time due to their abundance of sodium resources and low cost.However,the widespread application of SMBs as a viable technology remains a great chall...Sodium metal batteries(SMBs)have attracted increasing attention over time due to their abundance of sodium resources and low cost.However,the widespread application of SMBs as a viable technology remains a great challenge,such as uneven metallic deposition and dendrite formation during cycling.Carbon skeletons as sodiophilic hosts can alleviate the dendrite formation during the plating/stripping.For the carbon skeleton,how to rationalize the design sodiophilic interfaces between the sodium metal and carbon species remains key to developing desirable Na anodes.Herein,we fabricated four kinds of structural features for carbon skeletons using conventional calcination and flash Joule heating.The roles of conductivity,defects,oxygen content,and the distribution of graphite for the deposition of metallic sodium were discussed in detail.Based on interface engineering,the J1600 electrode,which has abundant Na-C species on its surface,showed the highest sodiophilic.There are uniform and rich F-Na species distributed in the inner solid electrolyte interface layer.This study investigated the different Na-deposition behavior in carbon hosts with distinct graphitic arrangements to pave the way for designing and optimizing advanced electrode materials.展开更多
Developing fluorescence porous probe for detecting and eliminating Cu^(2+) contamination in water or biosystem is an essential research project that has attracted considerable attention.However,improving the fluoresce...Developing fluorescence porous probe for detecting and eliminating Cu^(2+) contamination in water or biosystem is an essential research project that has attracted considerable attention.However,improving the fluorescence detecting efficiency while enhancing the adsorption capacity of the porous probe is of great challenge.Herein,a bifunctional two-dimensional imine-based porous covalent organic framework(TTP-COF)probe was designed and synthesized from 1,3,5-tris(4-aminophenyl)benzene(TAPB)and 2,4,6-Triformylphloroglucinol(TP)ligand.TTP-COF displayed rapid detection of Cu^(2+)(limit of detection(LOD)=10 nmol·L^(−1) while achieving a high adsorption capacity of 214 mg·g^(−1)(pH=6)at room temperature with high reusability(>5 cycles).The key roles and contributions of highπ-conjugate and delocalized electrons in TABP and functional–OH groups in TP were proved.More importantly,the fluorescence quenching mechanism of TTP-COF was studied by density functional theory theoretical calculations,revealing the crucial role of intramolecular hydrogen bonds among C=N and–OH groups and the blocking of the excited state intramolecular proton transfer process in detecting process of Cu^(2+).展开更多
A hydrogen fluoride-free and chloro-free method for synthesizing LiPF_(6) was developed.Employing CaF_(2) as the direct fluorinating reagent instead of hydrogen fluoride made it much safer and more environmentfriendly...A hydrogen fluoride-free and chloro-free method for synthesizing LiPF_(6) was developed.Employing CaF_(2) as the direct fluorinating reagent instead of hydrogen fluoride made it much safer and more environmentfriendly than conventional methods and reduced the metal residues in product owing to the relatively low-acid reaction conditions less corrosive to equipments.The use of P_(2)O_(5) as phosphorus source instead of traditionally employed PCl_(5) significantly reduced the chloro residue in product.Ca(H_(2)PO_(4))_(2),the only by-product of the process,could be easily converted into Ca_(3)(PO_(4))_(2),a best-selling chemical.The above advantages not only reduce the production costs by ca.20%,but also significantly improve the product purity.The fluorine-oxygen exchange reaction is a completely new technique for LiPF_(6) production and may bring about technological revolution in the related industry.展开更多
Iron ore deposits hosted by Precambrian banded iron formation(BIF)are the most important source of mineable iron.In Cameroon,they are located in the southern part of the country.This study reports the petrological and...Iron ore deposits hosted by Precambrian banded iron formation(BIF)are the most important source of mineable iron.In Cameroon,they are located in the southern part of the country.This study reports the petrological and geochemical data of iron ores collected from a weathering profile in the Mamelles BIF deposit,SW Cameroon.The profile is composed of three levels which are from the bottom to the top:the saprock,the ferruginous horizon,and the loose horizon.Eight representative iron ore samples(rock fragments and loose clayey material)were collected along the profile and were subjected to petrographic and geochemical analyses.Their mineralogy consists of martite,goethite,quartz,and lesser amounts of hematite,magnetite,kaolinite,and halloysite.The presence of minerals such as kaolinite and goethite in the Mamelles iron ores suggests their supergene origin.Geochemically,the saprock is characterized by high iron content(70.25 wt%Fe_(2)O_(3) t),and low silica(26.38 wt%SiO_(2))and alumina(1.14 wt%Al_(2) O_(3)).The rock fragments collected from the ferruginous horizon display higher Fe2 O3 t(72-76.40 wt%),Al_(2) O_(3)(2.80-5.43 wt%),and lower SiO_(2)(16.70-18.35 wt%)contents,suggesting the leaching of silica during the enrichment process.The loose clayey samples collected from both the ferruginous horizon and the upper loose horizon show lower iron and higher silica contents.When normalized to the underlying BIF saprock,both rock fragments and loose clayey ores display LREE enrichment,suggesting that they formed through supergene processes.Economically,most of the Mamelles iron ores are classified as medium-grade ores and a few display acceptable contents in contaminants.Overall,this petrological and geochemical study of the Mamelles iron ores revealed encouraging results.Given its strategic location near the deep seaport,the deposit should be investigated in more detail for its mining potential.展开更多
Development of highly-efficient photovoltaic (PV) modules and expanding its application fields are significant for the further development of PV technologies and realization of innovative green energy infrastructure b...Development of highly-efficient photovoltaic (PV) modules and expanding its application fields are significant for the further development of PV technologies and realization of innovative green energy infrastructure based on PV. Especially, development of solar-powered vehicles as a new application is highly desired and very important for this end. This paper presents the impact of PV cell/module conversion efficiency on reduction in CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> emission and increase in driving range of the electric based vehicles. Our studies show that the utilization of a highly-efficient (higher than 30%) PV module enables the solar-powered vehicle to drive 30 km/day without charging in the case of light weig</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">h</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">t cars with elec</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">t</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ric mileage of 17</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">km/kWh under solar irrad</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">i</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">a</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">t</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ion of 3.7</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">kWh/m</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">/day, which means that the majority of the family cars in Japan can run only by the sunlight without supplying fossil fuels. Thus, it is essential to develop high-efficiency as well as low-cost solar cells and modules for automotive applications. The analytical results developed by the authors for conversion efficiency potential of various solar cells for choosing candidates of the PV modules for automotive applications are shown. Then we overview the conversion efficiency potential and recent progress of various Si tandem solar cells, such as III-V/Si, II-VI/Si, chalcopyrite/Si, and perovskite/Si tandem solar cells. The III-V/Si tandem solar cells are expected to have a high potential for various applications because of its high conversion efficiency of larger than 36% for dual-junction and 42% for triple-junction solar cells under 1-sun AM1.5 G illumination, lightweight and low-cost potentials. The analysis show</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> that III-V based multi-junction and Si based tandem solar cells are considered to be promising candidates for the automotive application. Finally, we report recent results for our 28.2% efficiency and Sharp’s 33% mechanically stacked InGaP/GaAs/Si triple-junction solar cell. In addition, new approaches which </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> suitable for automotive applications by using III-V triple-junction, and static low concentrator PV modules are also presented.展开更多
The origin and petrogenesis of the Cameroon Volcanic Line （CVL）, composed of volcanoes that form on both the ocean floor and the continental crust, are difficult to understand because of the diversity, het- erogenei...The origin and petrogenesis of the Cameroon Volcanic Line （CVL）, composed of volcanoes that form on both the ocean floor and the continental crust, are difficult to understand because of the diversity, het- erogeneity, and nature of available data. Major and trace elements, and Sr-Nd-Pb isotope data of volcanic rocks of the CVL spanning four decades have been compiled to reinterpret their origin and petrogenesis. Volcanic rocks range from nephelinite, basanite and alkali basalts to phonolite, trachyte and rhyolite with the presence of a compositional gap between Si02 58-64 wt.%. Similarities in geochemical characteristics, modeled results for two component mixing, and the existence of mantle xenoliths in most mafic rocks argue against significant crustal contamination. Major and trace element evidences indicate that the melting of mantle rocks to generate the CVL magma occurred dominantly in the garnet lherzolite stability feld. Melting models suggest small degree （〈3%） partial melting of mantle bearing （6-10%） garnet for Mr. Etinde, the Ngaoundere Plateau and the Biu Plateau, and 〈5% of garnet for the oceanic sector of the CVL, Mr. Cameroon, Mt. Bambouto, Mt. Manengouba and the Oku Volcanic Group. The Sr-Nd-Pb isotope sys- tematics suggest that mixing in various proportions of Depleted MORB Mantle （DMM） with enriched mantle 1 and 2 （EM1 and EM2） could account for the complex isotopic characteristics of the CVL lavas. Low Mg number （Mg# - 100 x MgO/（MgO ＋FeO）） and Ni, Cr and Co contents of the CVL mafic lavas reveal their crystallization from fractionated melts. The absence of systematic variation in NbJTa and Zr/Hf ratios, and Sr-Nd isotope compositions between the mafic and felsic lavas indicates progressive evolution of magmas by fractional crystallization. Trace element ratios and their plots corroborate mantle het- erogeneity and reveal distinct geochemical signatures for individual the CVL volcanoes.展开更多
OBJECTIVE The emerging role of chronic inflammation is the major degenerative diseases of modern society such as periodontitis,atherosclerosis,rheumatoid arthritis,Parkinson′s disease and even cancer.Eight components...OBJECTIVE The emerging role of chronic inflammation is the major degenerative diseases of modern society such as periodontitis,atherosclerosis,rheumatoid arthritis,Parkinson′s disease and even cancer.Eight components were isolated from Derris laxiflora Benth.,In this study,we found these compounds from Derris laxiflora Benth suppress lipopolysaccharide-induced inflammatory response in murine macrophage(RAW 264.7)cells.METHODS RAW 264.7cells were cultured in DMEM media supplemented with 10%(V/V)heated-inactivated FBS,penicillin 100U·mL-1 and streptomycin 100μg·mL-1.The cells were incubated at 37℃in a humidified atmosphere of 5%CO2in air.RAW264.7cells were seeded in a 24-well plate at a density of 2×105 mL-1 and then incubated with or without LPS(100ng·mL-1)in the absence or presence of compounds for 24 h.Effects of these isolates on NO production were measured indirectly by analysis of nitrite levels using the Griess reaction.Quercetin was used as a positive control.RESULTS ight components were isolated from Derris laxiflora Benth.,including three new pterocarpans 7,6′-dihydroxy-3′-methoxypterocarpan(1),derrispisatin(2),derriscoumaronochromone(3)and three new flavonoids cis-3,4′-dihydroxy-5,7-dimethoxyflavan(4),derriflavanone B(5),iso-lupinenol(6)as well as two known ones,lonchocarpol A(7)and lonchocarpol D(8).The structures of these new compounds were determined by analysis of their spectroscopic data.Raw264.7 cells were treated with the compounds from Derris laxiflora Benth for 24 h.Among them,compounds 5,7 and 8 significantly suppressed the NO production in LPS-treated RAW264.7 cells with IC50 values<10μg·mL-1.CONCLUSION In this study,we found that compounds from Derris laxiflora Benth suppresses lipopolysaccharide-induced inflammatory response in murine Raw264.7 cells.展开更多
Although lithium(Li)metal delivers the highest theoretical capacity as a battery anode,its high reactivity can generate Li dendrites and"dead"Li during cycling,resulting in poor reversibility and low Li util...Although lithium(Li)metal delivers the highest theoretical capacity as a battery anode,its high reactivity can generate Li dendrites and"dead"Li during cycling,resulting in poor reversibility and low Li utilization.Inducing uniform Li plating/stripping is the core of solving these problems.Herein,we design a highly lithiophilic carbon film with an outer sheath of the nanoneedle arrays to induce homogeneous Li plating/stripping.The excellent conductivity and 3D framework of the carbon film not only offer fast charge transport across the entire electrode but also mitigate the volume change of Li metal during cycling.The abundant lithiophilic sites ensure stable Li plating/stripping,thereby inhibiting the Li dendritic growth and"dead"Li formation.The resulting composite anode allows for stable Li stripping/plating under 0.5 mA cm^(-2) with a capacity of 0.5 mA h cm^(-2) for 4000 h and 3 mA cm^(-2) with a capacity of3 mA h cm^(-2) for 1000 h.The Ex-SEM analysis reveals that lithiophilic property is different at the bottom,top,or channel in the structu re,which can regulate a bottom-up uniform Li deposition behavior.Full cells paired with LFP show a stable capacity of 155 mA h g^(-1) under a current density of 0.5C.The pouch cell can keep powering light-emitting diode even under 180°bending,suggesting its good flexibility and great practical applications.展开更多
In the past decades, several iron ore occurrences have been discovered in the Precambrian Belt of southern Cameroon, with focus on their economic potential, and little attention on the deposit type. However, few studi...In the past decades, several iron ore occurrences have been discovered in the Precambrian Belt of southern Cameroon, with focus on their economic potential, and little attention on the deposit type. However, few studies have been geared towards understanding the different deposit types within this region. This paper seeks to provide new insight on the different styles of iron ore mineralisation of two potential, yet least studied iron ore deposits in this region in addition to enhancing exploration efforts within the different prospects. Petrology and geochemistry of rock samples from the Binga and Djadom iron prospects in southern Cameroon are investigated. The structural disposition of the prospects was mapped and cores described, sampled and subsequently analysed to enhance the understanding of the alteration mineralogy, ore mineralogy and textural features of the iron-bearing lithologies. Polished thin sections were studied by standard microscopy while the bulk rock geochemistry was determined by X-ray fluorescence (XRF) for major and trace elements. At Binga, the main rock types are magnetite gneisses, amphibolites, quartz-biotite gneisses, and mafic intrusions, while the main rocks encountered at Djadom are magnetite gneisses, amphibolitic BIFs, quartz-biotite gneisses, amphibolites and fault rocks. At both prospects, the target lithology for iron ore is the magnetite gneiss. The magnetite gneisses at the Binga prospect are weakly to moderately foliated, but strongly foliated at Djadom, and both contain fractures that are healed by irregular magnetite. Magnetite is anhedral to euhedral in outline and it is closely associated with amphibole, garnet and pyroxene. Iron content of the magnetite gneisses ranges from 17.44 - 33.40 wt% (at Binga) and 27.73 - 43.39 wt% (at Djadom) and the ore enrichment process involved progressive loss of silica and aluminium. Trace element concentrations show high contents of Ba, Zn, Cu and V but lower abundances of Sr and Zr, as well as low values for Ti in both prospects. At the Binga iron ore prospect, TiO<sub>2</sub> and Al<sub>2</sub>O<sub>3</sub> display a linear co-variation with Zr, while in the Djadom prospect, TiO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub> and MgO display a negative co-variation with Zr. The origin of the former could be linked to a magmatic fluid-related process, while the genesis of the later is tied to both skarn formation and hydrothermal enrichment.展开更多
Special geographical location,topography and landform in Xinzhou region decide different climate characteristics in the area under its jurisdiction.Different change characteristics of temperature increase its forecast...Special geographical location,topography and landform in Xinzhou region decide different climate characteristics in the area under its jurisdiction.Different change characteristics of temperature increase its forecast difficulty.To understand occurrence time of daily highest and lowest temperature,Xinfu District was taken as research area,and actual lowest and highest temperature at automatic station of Xinfu District in 2014 was used.Analytic results showed that occurrence time of daily highest and lowest temperature was different in different seasons,and distribution characteristics of daily highest and lowest temperature were also different in each region.Moreover,forecast method and idea were proposed.展开更多
The multilayer of polyethylenimine (PEI) and carrageenan (k, i, l) formed by layer-by-layer assembly was investigated for its antibacterial activity against Enterobacter cloaceae, Staphylococcus aureus and Enterococcu...The multilayer of polyethylenimine (PEI) and carrageenan (k, i, l) formed by layer-by-layer assembly was investigated for its antibacterial activity against Enterobacter cloaceae, Staphylococcus aureus and Enterococcus faecalis 29505 for potential use as coating on biomaterial surface. All the multilayers exhibited growth inhibition. PEI/Iota carrageenan multilayer was effective in inhibiting the growth of the E. cloaceae, S. aureus and E. faecalis while PEI/Lambda carrageenan was effective in inhibiting the growth of E. cloaceae. Results of the paper strip test for combined action of carrageenan and PEI showed synergism with regards to bacterial growth inhibition. The multilayers had also contact-killing effect with the test organisms. The multilayer was also characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and biomolecular interaction analysis.展开更多
Mild hydrochloric acid hydrolysis of i-carrageenan from Eucheuma spinosum yielded two oligosaccharides of sulfated tetrasaccharide structure. These were characterized by Fourier Transform Infrared Spectroscopy (FT-IR)...Mild hydrochloric acid hydrolysis of i-carrageenan from Eucheuma spinosum yielded two oligosaccharides of sulfated tetrasaccharide structure. These were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Nuclear Magnetic Resonance (NMR) and Electrospray Ionization Mass Spectrometry (ESIMS). Both oligosaccharides have structure of b-D-galactopyranose(Galp)4S-(1→4)-α-D-AnGalp2S-(1→3)-b-D-galactopyranose Galp)4S-(1→4)-α-D-AnGalp2S-(1→3). Application of the resulting oligosaccharides on protein delivery system in terms of encapsulation efficiency was performed.展开更多
Manufactured nanomaterials are expected to enter the environment due to the increasing number of productions which results in anthropological discharges coming from different effluents and seepages.This event poses po...Manufactured nanomaterials are expected to enter the environment due to the increasing number of productions which results in anthropological discharges coming from different effluents and seepages.This event poses potential threat to the environment especially in the aquatic systems.TiO2(titanium dioxide)and AgNPs(silver nanoparticles)have significant potential in antibacterial and antiparasitic applications,but despite their significant potential,the toxicity of metal oxide nanoparticles such as TiO2 and AgNPs restricts their use especially in humans due to their toxicity.In this study,the behavior and toxicity of TiO2 and AgNPs were investigated in aquatic system using Artemia franciscana nauplii and Daphnia magna.Nauplii and Daphnia were exposed to TiO2 and AgNP dispersions at different concentrations.The mortality rates of the nauplii and daphnia were monitored at 6,24,and 48 h after its exposure.Saltwater results showed that AgNP is highly toxic to the test organisms while TiO2 was non-toxic after 48 h of exposure.For freshwater,100%mortality rate on neonates was obtained from the AgNPs dispersion during the first 6 h of exposure while the mortality rate in TiO2 dispersion was 85%at 100 ppm after 48 h of exposure.展开更多
The application of HVAC system is of great significance to the adjustment of indoor temperature, so as to meet peoples daily life needs and the quality of construction, but also determines whether people can obtain a ...The application of HVAC system is of great significance to the adjustment of indoor temperature, so as to meet peoples daily life needs and the quality of construction, but also determines whether people can obtain a better quality of life. This paper mainly introduces the specific principles of HVAC installation as well as the current main existing problems, and further puts forward the means of improving the construction quality control of building HVAC engineering, hoping to put forward more reference significance for the construction of HVAC engineering, to ensure the safe and stable operation of HVAC engineering.展开更多
With the development and expansion of state-owned enterprises, in the process of modernization, the human resource management of state-owned enterprises has always been the most important research content, because the...With the development and expansion of state-owned enterprises, in the process of modernization, the human resource management of state-owned enterprises has always been the most important research content, because the personnel of state-owned enterprises will have a great influence on national development and social construction, and even the improvement of national security and stability. Considering the new characteristics of human resources management in state-owned enterprises, it is necessary to continuously adjust and improve the mechanism.展开更多
The crystal structure, electrical and optical properties of ZnSe thin films deposited on an In203 ：Sn （ITO） substrate are evaluated for their suitability as the window layer of CdTe thin film solar cells. ZnSe thin...The crystal structure, electrical and optical properties of ZnSe thin films deposited on an In203 ：Sn （ITO） substrate are evaluated for their suitability as the window layer of CdTe thin film solar cells. ZnSe thin films of 80, 90, and 100 nm thickness were deposited by a physical vapor deposition method on Indium tin oxide coated glass substrates. The lattice parameters are increased to 5.834 A when the film thickness was 100 rim, which is close to that of CdS. The crystallite size is decreased with the increase of film thickness. The optical transmission analysis shows that the energy gap for the sample with the highest thickness has also increased and is very close to 2.7 eV. The photo decay is also studied as a function of ZnSe film thickness.展开更多
Iron and nitrogen co-doped carbon(Fe-N-C)materials are promising oxygen reduction reaction(ORR)catalysts due to its considerable catalytic performance[1–4].Currently,the catalytic activity of the Fe-N-C materials sti...Iron and nitrogen co-doped carbon(Fe-N-C)materials are promising oxygen reduction reaction(ORR)catalysts due to its considerable catalytic performance[1–4].Currently,the catalytic activity of the Fe-N-C materials still cannot match the performance of commercial Pt/C electrocatalysts due to its low density of active sites.Atomic dispersion of catalytic active sites is a promising method for improving catalytic efficiency,and making展开更多
10Gbit/s time-spread/wavelength-hop optical code generation and decoding are performed by dispersion-compensating fiber Bragg grating (FBG) en/decoder pair. Error-free 10km single mode fiber (SMF) transmission of 10Gb...10Gbit/s time-spread/wavelength-hop optical code generation and decoding are performed by dispersion-compensating fiber Bragg grating (FBG) en/decoder pair. Error-free 10km single mode fiber (SMF) transmission of 10Gbit/s optical code division multiplexing (OCDM) has been experimentally demonstrated.展开更多
基金financially supported by the Natural Science Foundation of Jiangsu Province(No.BK20181449)Jiangsu Provincial Six Talent Peaks Project(No.XCL-090)Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘Herein we wish to propose the concept of"element-transfer reaction",which may afford the access to elemental compounds by transferring certain elements from easily available resources efficiently,concisely and precisely.A good element-transfer reaction with industrial application potential shall not generate waste and is performed under energy-saving and environment-friendly conditions.During the past decade,we have developed a series of methods for the synthesis of fluorine-and seleniumcontaining compounds via the fluorine-and selenium-transfer reactions,while the redox reactions we re considered to be the oxygen-and hydrogen-transfer reactions as well and were also widely studied by our group for producing the high-value-added fine chemicals.Some of these technologies have been successfully industrialized.This review summarizes our staged research results on fluorine-,oxygen-,hydrogen-and selenium-transfer reactions and makes a prospect on the developing trend in the field.
基金supported by the National Natural Science Foundation of China(32271799,31870570)the Science and Technology Plan of Fujian Provincial,China(3502ZCQXT2022001,2020H4026,2022G02020 and 2022H6002)the Scientific Research Start–up Funding for Special Professor of Minjiang Scholars。
文摘Sodium metal batteries(SMBs)have attracted increasing attention over time due to their abundance of sodium resources and low cost.However,the widespread application of SMBs as a viable technology remains a great challenge,such as uneven metallic deposition and dendrite formation during cycling.Carbon skeletons as sodiophilic hosts can alleviate the dendrite formation during the plating/stripping.For the carbon skeleton,how to rationalize the design sodiophilic interfaces between the sodium metal and carbon species remains key to developing desirable Na anodes.Herein,we fabricated four kinds of structural features for carbon skeletons using conventional calcination and flash Joule heating.The roles of conductivity,defects,oxygen content,and the distribution of graphite for the deposition of metallic sodium were discussed in detail.Based on interface engineering,the J1600 electrode,which has abundant Na-C species on its surface,showed the highest sodiophilic.There are uniform and rich F-Na species distributed in the inner solid electrolyte interface layer.This study investigated the different Na-deposition behavior in carbon hosts with distinct graphitic arrangements to pave the way for designing and optimizing advanced electrode materials.
基金This study was financially supported by the National Natural Science Foundation of China(Nos.22001156 and 22271178)the Innovation Capability Support Program of Shaanxi(No.2022KJXX-88)the Technology Innovation Leading Program of Shaanxi(No.2020QFY07-05).
文摘Developing fluorescence porous probe for detecting and eliminating Cu^(2+) contamination in water or biosystem is an essential research project that has attracted considerable attention.However,improving the fluorescence detecting efficiency while enhancing the adsorption capacity of the porous probe is of great challenge.Herein,a bifunctional two-dimensional imine-based porous covalent organic framework(TTP-COF)probe was designed and synthesized from 1,3,5-tris(4-aminophenyl)benzene(TAPB)and 2,4,6-Triformylphloroglucinol(TP)ligand.TTP-COF displayed rapid detection of Cu^(2+)(limit of detection(LOD)=10 nmol·L^(−1) while achieving a high adsorption capacity of 214 mg·g^(−1)(pH=6)at room temperature with high reusability(>5 cycles).The key roles and contributions of highπ-conjugate and delocalized electrons in TABP and functional–OH groups in TP were proved.More importantly,the fluorescence quenching mechanism of TTP-COF was studied by density functional theory theoretical calculations,revealing the crucial role of intramolecular hydrogen bonds among C=N and–OH groups and the blocking of the excited state intramolecular proton transfer process in detecting process of Cu^(2+).
基金supported by Yangzhou University-Hongfu Lithium joint-laboratory projectJiangsu Provincial Six Talent Peaks Project(No.XCL-090)+1 种基金the Special Funds for Industrial Transformation and Upgrading and Information Industry Development of Gansu Province in 2018(the First Phase Construction of Lithium Battery-Related New Material Industrial Park-the LiPF6 Production Project)Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)。
文摘A hydrogen fluoride-free and chloro-free method for synthesizing LiPF_(6) was developed.Employing CaF_(2) as the direct fluorinating reagent instead of hydrogen fluoride made it much safer and more environmentfriendly than conventional methods and reduced the metal residues in product owing to the relatively low-acid reaction conditions less corrosive to equipments.The use of P_(2)O_(5) as phosphorus source instead of traditionally employed PCl_(5) significantly reduced the chloro residue in product.Ca(H_(2)PO_(4))_(2),the only by-product of the process,could be easily converted into Ca_(3)(PO_(4))_(2),a best-selling chemical.The above advantages not only reduce the production costs by ca.20%,but also significantly improve the product purity.The fluorine-oxygen exchange reaction is a completely new technique for LiPF_(6) production and may bring about technological revolution in the related industry.
文摘Iron ore deposits hosted by Precambrian banded iron formation(BIF)are the most important source of mineable iron.In Cameroon,they are located in the southern part of the country.This study reports the petrological and geochemical data of iron ores collected from a weathering profile in the Mamelles BIF deposit,SW Cameroon.The profile is composed of three levels which are from the bottom to the top:the saprock,the ferruginous horizon,and the loose horizon.Eight representative iron ore samples(rock fragments and loose clayey material)were collected along the profile and were subjected to petrographic and geochemical analyses.Their mineralogy consists of martite,goethite,quartz,and lesser amounts of hematite,magnetite,kaolinite,and halloysite.The presence of minerals such as kaolinite and goethite in the Mamelles iron ores suggests their supergene origin.Geochemically,the saprock is characterized by high iron content(70.25 wt%Fe_(2)O_(3) t),and low silica(26.38 wt%SiO_(2))and alumina(1.14 wt%Al_(2) O_(3)).The rock fragments collected from the ferruginous horizon display higher Fe2 O3 t(72-76.40 wt%),Al_(2) O_(3)(2.80-5.43 wt%),and lower SiO_(2)(16.70-18.35 wt%)contents,suggesting the leaching of silica during the enrichment process.The loose clayey samples collected from both the ferruginous horizon and the upper loose horizon show lower iron and higher silica contents.When normalized to the underlying BIF saprock,both rock fragments and loose clayey ores display LREE enrichment,suggesting that they formed through supergene processes.Economically,most of the Mamelles iron ores are classified as medium-grade ores and a few display acceptable contents in contaminants.Overall,this petrological and geochemical study of the Mamelles iron ores revealed encouraging results.Given its strategic location near the deep seaport,the deposit should be investigated in more detail for its mining potential.
文摘Development of highly-efficient photovoltaic (PV) modules and expanding its application fields are significant for the further development of PV technologies and realization of innovative green energy infrastructure based on PV. Especially, development of solar-powered vehicles as a new application is highly desired and very important for this end. This paper presents the impact of PV cell/module conversion efficiency on reduction in CO</span><sub><span style="font-family:Verdana;">2</span></sub><span style="font-family:Verdana;"> emission and increase in driving range of the electric based vehicles. Our studies show that the utilization of a highly-efficient (higher than 30%) PV module enables the solar-powered vehicle to drive 30 km/day without charging in the case of light weig</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">h</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">t cars with elec</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">t</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ric mileage of 17</span></span></span><span><span><span style="font-family:""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">km/kWh under solar irrad</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">i</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">a</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">t</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">ion of 3.7</span></span></span><span><span><span style="font-family:""> </span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;">kWh/m</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">/day, which means that the majority of the family cars in Japan can run only by the sunlight without supplying fossil fuels. Thus, it is essential to develop high-efficiency as well as low-cost solar cells and modules for automotive applications. The analytical results developed by the authors for conversion efficiency potential of various solar cells for choosing candidates of the PV modules for automotive applications are shown. Then we overview the conversion efficiency potential and recent progress of various Si tandem solar cells, such as III-V/Si, II-VI/Si, chalcopyrite/Si, and perovskite/Si tandem solar cells. The III-V/Si tandem solar cells are expected to have a high potential for various applications because of its high conversion efficiency of larger than 36% for dual-junction and 42% for triple-junction solar cells under 1-sun AM1.5 G illumination, lightweight and low-cost potentials. The analysis show</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> that III-V based multi-junction and Si based tandem solar cells are considered to be promising candidates for the automotive application. Finally, we report recent results for our 28.2% efficiency and Sharp’s 33% mechanically stacked InGaP/GaAs/Si triple-junction solar cell. In addition, new approaches which </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">are</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> suitable for automotive applications by using III-V triple-junction, and static low concentrator PV modules are also presented.
基金supported by Science and Technology Research Partnership for Sustainable Development(SATREPS)project titled:Magmatic Fluid Supply into Lakes Nyos and MonounMitigation of Natural Disasters through capacity building in Cameroon+2 种基金financial support is being provided by the Japan Science and Technology Agency(JST)Japan International Cooperation Agency(JICA)the Institute of Geological and Mining Research(IRGM)of the Cameroon Ministry of Scientific Research and Innovation(MINRESI)
文摘The origin and petrogenesis of the Cameroon Volcanic Line （CVL）, composed of volcanoes that form on both the ocean floor and the continental crust, are difficult to understand because of the diversity, het- erogeneity, and nature of available data. Major and trace elements, and Sr-Nd-Pb isotope data of volcanic rocks of the CVL spanning four decades have been compiled to reinterpret their origin and petrogenesis. Volcanic rocks range from nephelinite, basanite and alkali basalts to phonolite, trachyte and rhyolite with the presence of a compositional gap between Si02 58-64 wt.%. Similarities in geochemical characteristics, modeled results for two component mixing, and the existence of mantle xenoliths in most mafic rocks argue against significant crustal contamination. Major and trace element evidences indicate that the melting of mantle rocks to generate the CVL magma occurred dominantly in the garnet lherzolite stability feld. Melting models suggest small degree （〈3%） partial melting of mantle bearing （6-10%） garnet for Mr. Etinde, the Ngaoundere Plateau and the Biu Plateau, and 〈5% of garnet for the oceanic sector of the CVL, Mr. Cameroon, Mt. Bambouto, Mt. Manengouba and the Oku Volcanic Group. The Sr-Nd-Pb isotope sys- tematics suggest that mixing in various proportions of Depleted MORB Mantle （DMM） with enriched mantle 1 and 2 （EM1 and EM2） could account for the complex isotopic characteristics of the CVL lavas. Low Mg number （Mg# - 100 x MgO/（MgO ＋FeO）） and Ni, Cr and Co contents of the CVL mafic lavas reveal their crystallization from fractionated melts. The absence of systematic variation in NbJTa and Zr/Hf ratios, and Sr-Nd isotope compositions between the mafic and felsic lavas indicates progressive evolution of magmas by fractional crystallization. Trace element ratios and their plots corroborate mantle het- erogeneity and reveal distinct geochemical signatures for individual the CVL volcanoes.
基金The project supported by Department of Industrial Technology,Ministry of Economic Affairs,Chinese TaipeiMedical and Pharmaceutical Industry Technology and Development Center
文摘OBJECTIVE The emerging role of chronic inflammation is the major degenerative diseases of modern society such as periodontitis,atherosclerosis,rheumatoid arthritis,Parkinson′s disease and even cancer.Eight components were isolated from Derris laxiflora Benth.,In this study,we found these compounds from Derris laxiflora Benth suppress lipopolysaccharide-induced inflammatory response in murine macrophage(RAW 264.7)cells.METHODS RAW 264.7cells were cultured in DMEM media supplemented with 10%(V/V)heated-inactivated FBS,penicillin 100U·mL-1 and streptomycin 100μg·mL-1.The cells were incubated at 37℃in a humidified atmosphere of 5%CO2in air.RAW264.7cells were seeded in a 24-well plate at a density of 2×105 mL-1 and then incubated with or without LPS(100ng·mL-1)in the absence or presence of compounds for 24 h.Effects of these isolates on NO production were measured indirectly by analysis of nitrite levels using the Griess reaction.Quercetin was used as a positive control.RESULTS ight components were isolated from Derris laxiflora Benth.,including three new pterocarpans 7,6′-dihydroxy-3′-methoxypterocarpan(1),derrispisatin(2),derriscoumaronochromone(3)and three new flavonoids cis-3,4′-dihydroxy-5,7-dimethoxyflavan(4),derriflavanone B(5),iso-lupinenol(6)as well as two known ones,lonchocarpol A(7)and lonchocarpol D(8).The structures of these new compounds were determined by analysis of their spectroscopic data.Raw264.7 cells were treated with the compounds from Derris laxiflora Benth for 24 h.Among them,compounds 5,7 and 8 significantly suppressed the NO production in LPS-treated RAW264.7 cells with IC50 values<10μg·mL-1.CONCLUSION In this study,we found that compounds from Derris laxiflora Benth suppresses lipopolysaccharide-induced inflammatory response in murine Raw264.7 cells.
基金supported by the National Natural Science Foundation of China(31870570)the Science and Technology Plan of Fujian Provincial,China(2020H4026,2022G02020 and 2022H6002)+1 种基金the Science and Technology Plan of Xiamen(3502Z20203005)the Scientific Research Start-up Funding for Special Professor of Minjiang Scholars。
文摘Although lithium(Li)metal delivers the highest theoretical capacity as a battery anode,its high reactivity can generate Li dendrites and"dead"Li during cycling,resulting in poor reversibility and low Li utilization.Inducing uniform Li plating/stripping is the core of solving these problems.Herein,we design a highly lithiophilic carbon film with an outer sheath of the nanoneedle arrays to induce homogeneous Li plating/stripping.The excellent conductivity and 3D framework of the carbon film not only offer fast charge transport across the entire electrode but also mitigate the volume change of Li metal during cycling.The abundant lithiophilic sites ensure stable Li plating/stripping,thereby inhibiting the Li dendritic growth and"dead"Li formation.The resulting composite anode allows for stable Li stripping/plating under 0.5 mA cm^(-2) with a capacity of 0.5 mA h cm^(-2) for 4000 h and 3 mA cm^(-2) with a capacity of3 mA h cm^(-2) for 1000 h.The Ex-SEM analysis reveals that lithiophilic property is different at the bottom,top,or channel in the structu re,which can regulate a bottom-up uniform Li deposition behavior.Full cells paired with LFP show a stable capacity of 155 mA h g^(-1) under a current density of 0.5C.The pouch cell can keep powering light-emitting diode even under 180°bending,suggesting its good flexibility and great practical applications.
文摘In the past decades, several iron ore occurrences have been discovered in the Precambrian Belt of southern Cameroon, with focus on their economic potential, and little attention on the deposit type. However, few studies have been geared towards understanding the different deposit types within this region. This paper seeks to provide new insight on the different styles of iron ore mineralisation of two potential, yet least studied iron ore deposits in this region in addition to enhancing exploration efforts within the different prospects. Petrology and geochemistry of rock samples from the Binga and Djadom iron prospects in southern Cameroon are investigated. The structural disposition of the prospects was mapped and cores described, sampled and subsequently analysed to enhance the understanding of the alteration mineralogy, ore mineralogy and textural features of the iron-bearing lithologies. Polished thin sections were studied by standard microscopy while the bulk rock geochemistry was determined by X-ray fluorescence (XRF) for major and trace elements. At Binga, the main rock types are magnetite gneisses, amphibolites, quartz-biotite gneisses, and mafic intrusions, while the main rocks encountered at Djadom are magnetite gneisses, amphibolitic BIFs, quartz-biotite gneisses, amphibolites and fault rocks. At both prospects, the target lithology for iron ore is the magnetite gneiss. The magnetite gneisses at the Binga prospect are weakly to moderately foliated, but strongly foliated at Djadom, and both contain fractures that are healed by irregular magnetite. Magnetite is anhedral to euhedral in outline and it is closely associated with amphibole, garnet and pyroxene. Iron content of the magnetite gneisses ranges from 17.44 - 33.40 wt% (at Binga) and 27.73 - 43.39 wt% (at Djadom) and the ore enrichment process involved progressive loss of silica and aluminium. Trace element concentrations show high contents of Ba, Zn, Cu and V but lower abundances of Sr and Zr, as well as low values for Ti in both prospects. At the Binga iron ore prospect, TiO<sub>2</sub> and Al<sub>2</sub>O<sub>3</sub> display a linear co-variation with Zr, while in the Djadom prospect, TiO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub> and MgO display a negative co-variation with Zr. The origin of the former could be linked to a magmatic fluid-related process, while the genesis of the later is tied to both skarn formation and hydrothermal enrichment.
文摘Special geographical location,topography and landform in Xinzhou region decide different climate characteristics in the area under its jurisdiction.Different change characteristics of temperature increase its forecast difficulty.To understand occurrence time of daily highest and lowest temperature,Xinfu District was taken as research area,and actual lowest and highest temperature at automatic station of Xinfu District in 2014 was used.Analytic results showed that occurrence time of daily highest and lowest temperature was different in different seasons,and distribution characteristics of daily highest and lowest temperature were also different in each region.Moreover,forecast method and idea were proposed.
文摘The multilayer of polyethylenimine (PEI) and carrageenan (k, i, l) formed by layer-by-layer assembly was investigated for its antibacterial activity against Enterobacter cloaceae, Staphylococcus aureus and Enterococcus faecalis 29505 for potential use as coating on biomaterial surface. All the multilayers exhibited growth inhibition. PEI/Iota carrageenan multilayer was effective in inhibiting the growth of the E. cloaceae, S. aureus and E. faecalis while PEI/Lambda carrageenan was effective in inhibiting the growth of E. cloaceae. Results of the paper strip test for combined action of carrageenan and PEI showed synergism with regards to bacterial growth inhibition. The multilayers had also contact-killing effect with the test organisms. The multilayer was also characterized by atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS) and biomolecular interaction analysis.
文摘Mild hydrochloric acid hydrolysis of i-carrageenan from Eucheuma spinosum yielded two oligosaccharides of sulfated tetrasaccharide structure. These were characterized by Fourier Transform Infrared Spectroscopy (FT-IR), Nuclear Magnetic Resonance (NMR) and Electrospray Ionization Mass Spectrometry (ESIMS). Both oligosaccharides have structure of b-D-galactopyranose(Galp)4S-(1→4)-α-D-AnGalp2S-(1→3)-b-D-galactopyranose Galp)4S-(1→4)-α-D-AnGalp2S-(1→3). Application of the resulting oligosaccharides on protein delivery system in terms of encapsulation efficiency was performed.
文摘Manufactured nanomaterials are expected to enter the environment due to the increasing number of productions which results in anthropological discharges coming from different effluents and seepages.This event poses potential threat to the environment especially in the aquatic systems.TiO2(titanium dioxide)and AgNPs(silver nanoparticles)have significant potential in antibacterial and antiparasitic applications,but despite their significant potential,the toxicity of metal oxide nanoparticles such as TiO2 and AgNPs restricts their use especially in humans due to their toxicity.In this study,the behavior and toxicity of TiO2 and AgNPs were investigated in aquatic system using Artemia franciscana nauplii and Daphnia magna.Nauplii and Daphnia were exposed to TiO2 and AgNP dispersions at different concentrations.The mortality rates of the nauplii and daphnia were monitored at 6,24,and 48 h after its exposure.Saltwater results showed that AgNP is highly toxic to the test organisms while TiO2 was non-toxic after 48 h of exposure.For freshwater,100%mortality rate on neonates was obtained from the AgNPs dispersion during the first 6 h of exposure while the mortality rate in TiO2 dispersion was 85%at 100 ppm after 48 h of exposure.
文摘The application of HVAC system is of great significance to the adjustment of indoor temperature, so as to meet peoples daily life needs and the quality of construction, but also determines whether people can obtain a better quality of life. This paper mainly introduces the specific principles of HVAC installation as well as the current main existing problems, and further puts forward the means of improving the construction quality control of building HVAC engineering, hoping to put forward more reference significance for the construction of HVAC engineering, to ensure the safe and stable operation of HVAC engineering.
文摘With the development and expansion of state-owned enterprises, in the process of modernization, the human resource management of state-owned enterprises has always been the most important research content, because the personnel of state-owned enterprises will have a great influence on national development and social construction, and even the improvement of national security and stability. Considering the new characteristics of human resources management in state-owned enterprises, it is necessary to continuously adjust and improve the mechanism.
文摘The crystal structure, electrical and optical properties of ZnSe thin films deposited on an In203 ：Sn （ITO） substrate are evaluated for their suitability as the window layer of CdTe thin film solar cells. ZnSe thin films of 80, 90, and 100 nm thickness were deposited by a physical vapor deposition method on Indium tin oxide coated glass substrates. The lattice parameters are increased to 5.834 A when the film thickness was 100 rim, which is close to that of CdS. The crystallite size is decreased with the increase of film thickness. The optical transmission analysis shows that the energy gap for the sample with the highest thickness has also increased and is very close to 2.7 eV. The photo decay is also studied as a function of ZnSe film thickness.
基金supported by the Beijing Natural Science Foundation (2172051)State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, Donghua University,the Open Funds of the State Key Laboratory of Electroanalytical Chemistry SKLEAC201708)
文摘Iron and nitrogen co-doped carbon(Fe-N-C)materials are promising oxygen reduction reaction(ORR)catalysts due to its considerable catalytic performance[1–4].Currently,the catalytic activity of the Fe-N-C materials still cannot match the performance of commercial Pt/C electrocatalysts due to its low density of active sites.Atomic dispersion of catalytic active sites is a promising method for improving catalytic efficiency,and making
文摘10Gbit/s time-spread/wavelength-hop optical code generation and decoding are performed by dispersion-compensating fiber Bragg grating (FBG) en/decoder pair. Error-free 10km single mode fiber (SMF) transmission of 10Gbit/s optical code division multiplexing (OCDM) has been experimentally demonstrated.
