We demonstrate a home-built electrochemical scanning tunneling microscope （ECSTM）. The ECSTM exhibits highly stable performance. The drifting rates in XY and Z directions of the ECSTM are about 67 and 55.6 pm/min, r...We demonstrate a home-built electrochemical scanning tunneling microscope （ECSTM）. The ECSTM exhibits highly stable performance. The drifting rates in XY and Z directions of the ECSTM are about 67 and 55.6 pm/min, respectively. Moreover, a specially designed scanner unit successfully solves the well-known problem of large leakage current in high humidity atmosphere. The mechanical structure of the ECSTM is described in detail. The excellent performances of the system are demonstrated by the measured STM images （in copper sulfate solution）, including clean and well-ordered large area morphology of Au（111） and the atomically resolved image of highly oriented pyrolytic graphite.展开更多
Bismuth-based fluoride nanocrystalline materials are an emerging class of host matrixes for luminescent ions with promising applications in optoelectronic devices and medical diagnosis.However,rapid aqueous-phase synt...Bismuth-based fluoride nanocrystalline materials are an emerging class of host matrixes for luminescent ions with promising applications in optoelectronic devices and medical diagnosis.However,rapid aqueous-phase synthesis of highly stable bismuth-based fluoride nanocrystals at low temperature(room temperature∼90℃)is still a significant challenge.Herein we report an ultrafast(1 min only)and economical aqueous method to synthesize lanthanide-doped K_(0.3)Bi_(0.7)F_(2.4)upconversion nanocrystalline particles at low temperature.The resultant materials show exceptional upconversion luminescence performance under the excitation of a 980 nm near-infrared laser.More importantly,these fluoride nanocrystalline particles show excellent stability against high temperature up to 200℃,high excitation power density(80 W cm^(−2))and prolonged water soaking(60 days or more).The proposed simple synthesis route,rare-earth free fluoride matrix,commendable upconversion luminescence performance and excellent chemical and thermal stability opens the door to access these lanthanide-doped K0.3Bi0.7F2.4 upconversion nanocrystalline particles for anti-counterfeiting and other daily applications.展开更多
Coordination engineering can enhance the activity and stability of the catalyst in heterogeneous catalysis.However,the axial coordination engineering between different groups on the carbon carrier and molecular cataly...Coordination engineering can enhance the activity and stability of the catalyst in heterogeneous catalysis.However,the axial coordination engineering between different groups on the carbon carrier and molecular catalysts in the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR)has been studied rarely.Through coordination engineering strategy,a series of amino(NH_(2)),hydroxyl(OH),and carboxyl(COOH)groups functionalized carbon nanotubes(CNT)immobilized cobalt phthalocyanine(CoPc)catalysts are designed.Compared with no groups,OH groups and COOH groups,NH_(2)groups can effectively change the coordination environment of the central metal Co,thereby significantly increasing the turnover frequency(TOF)(31.4 s^(-1)at-0.6 V vs.RHE,CoPc/NH_(2)-CNT>CoPc/OH-CNT>CoPc/COOH-CN>CoPc/CNT).In the flow cell,the CoPc/NH_(2)-CNT catalyst has high carbon monoxide(CO)selectivity at high current density(~100%at-225 mA·cm^(-2),~96%at-351 mA·cm^(-2)).Importantly,the CoPc/NH_(2)-CNT catalyst can operate stably for 100 h at 225 mA·cm^(-2).Theoretical calculations reveal that CoPc/NH_(2)-CNT catalyst is beneficial to the formation of^(*)COOH and desorption of^(*)CO,thus promoting CO_(2)RR.This work provides an excellent platform for understanding the effect of coordination engineering on electrocatalytic performance and promotes a way to explore efficient and stable catalysts in other applications.展开更多
We modify the pulse-reference-based compensation technique and propose a low-noise and highly stable optical fiber temperature sensor based on a zinc telluride film-coated fiber tip. The system noise is measured to be...We modify the pulse-reference-based compensation technique and propose a low-noise and highly stable optical fiber temperature sensor based on a zinc telluride film-coated fiber tip. The system noise is measured to be 0.0005 dB, which makes it possible for the detection of the minor reflectivity change of the film at different temperatures. The temperature sensitivity is 0.0034 d B/℃, so the resolution can achieve 0.2℃. The maximum difference of the temperature output values of the sensor at 20℃ at different points in time is 0.39℃. The low cost, ultra-small size, high stability, and good repeatability of the sensor make it a promising temperature sensing device for practical application.展开更多
The development of economical and stable catalyst electrodes for industrial-scale seawater splitting is one of the cur-rent challenges in hydrogen production.The economical transition metals possess high electrical co...The development of economical and stable catalyst electrodes for industrial-scale seawater splitting is one of the cur-rent challenges in hydrogen production.The economical transition metals possess high electrical conductivity and offer the potential for designing electrodes with high intrinsic activity through appropriate modifications,thus holding promising applications in industrial contexts.Herein,a durable and economical self-supported bifunctional electrode(Fe@Ni)with high efficiency and large area is successfully constructed by one step in-situ deposition of iron on the porous structure of nickel foam(NF)via mild(298 K)electroplating method.Transition metals like iron and nickel offer high electrical conductivity and can be properly modified to achieve electrodes with high intrinsic activity.Due to the in-situ growth of cost-effective iron on the NF surface,the electrode surface morphology and electronic structure are reconstructed,which significantly improves the electrochemical activity surface area and electron transfer capabil-ity of the electrode.The hydrogen/oxygen evolution reaction(HER/OER)in simulated seawater(1 M KOH+0.5 M NaCl)require only 129 mV and 323 mV overpotentials to achieve a current density of 100 mA cm^(-2).Overall seawater splitting(OWS)achieves 10 mA cm^(-2) at a low voltage of 1.49 V and with a faradaic efficiency of nearly 100%.More importantly,the bifunctional electrodes remain stable at industrial-level current density(1.0 A cm^(-2))for more than 50 days.More attractively,this work realizes the universal construction of large-area electrode for multiple metals(e.g.,Fe,Cu,Al,etc.)with mild and simple process,which provides a new strategy for the current research of energy and materials.展开更多
Unstable Zn interface caused by rampant dendrite growth and parasitic side reactions always hinders the practical application of aqueous zinc metal batteries(AZMBs),Herein,tyrosine(Tyr)with high molecular polarity was...Unstable Zn interface caused by rampant dendrite growth and parasitic side reactions always hinders the practical application of aqueous zinc metal batteries(AZMBs),Herein,tyrosine(Tyr)with high molecular polarity was introduced into aqueous electrolyte to modulate the interfacial electrochemistry of Zn anode.In AZMBs,the positively charged side of Tyr can be well adsorbed on the surface of Zn anode to form a water-poor layer,and the exposed carboxylate side can be easily coordinated with Zn^(2+),favoring inducing uniform plating of Zn^(2+)and inhibiting the occurrence of water-induced side reactions.These in turn enable the achievement of highly stable Zn anode.Accordingly,the Zn anodes achieve outstanding cyclic stability(3000 h at 2 mA cm^(-2),2 mA h cm^(-2)and 1300 h at 5 mA cm^(-2),5 mA h cm^(-2)),high average Coulombic efficiency(99.4%over 3200 cycles),and high depth of discharge(80%for 500 h).Besides,the assembled Zn‖NaV_(3)O_(8)·1.5H_(2)O full cells deliver remarkable capacity retention and ultra-long lifetime(61.8%over 6650 cycles at 5 A g^(-1))and enhanced rate capability(169 mA h g^(-1)at 5 A g^(-1)).The work may promote the design and deep understanding of electrolyte additives with high molecular polarity for high-performance AZMBs.展开更多
Highly efficient and stable hybrid white organic light-emitting diodes （HWOLEDs） with a mixed bipolar interlayer between fluorescent blue and phosphorescent yellow emitting layers are demonstrated. The bipolar inter...Highly efficient and stable hybrid white organic light-emitting diodes （HWOLEDs） with a mixed bipolar interlayer between fluorescent blue and phosphorescent yellow emitting layers are demonstrated. The bipolar interlayer is a mixture of p-type diphenyl （l0-phenyl-lOH-spiro [acridine-9,9＇-fluoren]-3Lyl） phosphine oxide and n-type 2＇,2- （1,3,5-benzinetriyl）-tris（1-phenyl-l-H-benzimidazole）. The electroluminance and Commission Internationale de l＇Eclairage （CIE1931） coordinates＇ characteristics can be modulated easily by adjusting the ratio of the hole- predominated material to the electron-predominated material in the interlayer. The hybrid WOLED with a p-type：n-type ratio of 1：3 shows a maximum current efficiency and power efficiency of 61.1 ed/A and 55.8 lm/W, respectively, with warm white CIE coordinates of （0.34, 0.43）. The excellent efficiency and adaptive CIE coordi- nates are attributed to the mixed interlayer with improved charge carrier balance, optimized exciton distribution, and enhanced harvesting of singlet and triplet excitons.展开更多
The membrane,one of the key components of flow batteries,ideally has high selectivity,conductivity,and stability.However,porous membranes prepared by conventional non-solvent-induced phase separation(NIPS)commonly suf...The membrane,one of the key components of flow batteries,ideally has high selectivity,conductivity,and stability.However,porous membranes prepared by conventional non-solvent-induced phase separation(NIPS)commonly suffer from low selectivity and poor mechanical stability.Here,we used rigid naphthalene-containing polybenzimidazole(NPBI)to prepare a porous membrane with unique egg-shaped pores by adjusting solvent/non-solvent exchange in NIPS.The dense pores with a size of 3.6Åarranged dispersedly between egg-shaped pores.The rigid NPBI and 3.6-Åsmall pores enabled the membrane high mechanical strength.The thickness was thus decreased to 1.4μm,which exhibited an ultrahigh tensile strength of 463.54 MPa.The dense pores were also smaller than hydrated vanadium ions,achieving a low permeability of 2.28×10^(-7)cm^(2)/h,indicating high selectivity.This is the first time to prepare such a highly selective and mechanically stable ultrathin porous membrane by NIPS.Importantly,the ion-transport pathways in the 1.4μm membrane were shortened,decreasing the area resistance to as low as 0.015Ωcm 2.Demonstrated in a vanadium flow battery,its coulombic efficiency was 98.57%and energy efficiency reached 81.72%at 200 mA/cm 2.This study proposes an effective strategy to prepare highperformance ultrathin porous membranes for flow batteries.展开更多
High efficiency, stable organic light-emitting diodes （OLEDs） based on 2-pheyl-4＇-carbazole-9-H-Thioxanthen-9- one-10, 10-dioxide （TXO-PhCz） with different doping concentration are constructed. The stability of t...High efficiency, stable organic light-emitting diodes （OLEDs） based on 2-pheyl-4＇-carbazole-9-H-Thioxanthen-9- one-10, 10-dioxide （TXO-PhCz） with different doping concentration are constructed. The stability of the encap- sulated devices are investigated in detail. The devices with the 10 wt% doped TXO-PhCz emitter layer （EML） show the best performance with a current efficiency of 52.1 cd/A, a power efficiency of 32.71re^W, and an external quantum efficiency （EQE） of 17.7%. The devices based on the lOwt%-doped TXO-PhCz EML show the best operational stability with a half-life time （LTSO） of 8Oh, which is 8 h longer than that of the reference devices based on fac-tris（2-phenylpyridinato）iridium（ Ⅲ） （Ir（ppy）a）. These indicate excellent stability of TXO-PhCz for redox and oxidation processes under electrical excitation and TXO-PhCz can be potentially used as the emitters for OLEDs with high efficiency and excellent stability. The high-performance device based on TXO-PhCz with high stability can be further improved by the optimization of the encapsulation technology and the development of a new host for TXO-PhCz.展开更多
This paper mainly introduces an output control method with high stable precision of a large power IGBT arc welding inverter. Experiments indicate that this kind of control mode can effectively improve the static and d...This paper mainly introduces an output control method with high stable precision of a large power IGBT arc welding inverter. Experiments indicate that this kind of control mode can effectively improve the static and dynamic characteristics and stability of power supply system. And it can decrease the spatters in the welding process apparently. This power supply is especially suitable to automatic robot welding assembly line. It will be the developing direction of robot welding supply in the future.展开更多
<span style="font-family:;" "=""><span style="font-family:Verdana;">In this paper, it was introduced that </span><i><span style="font-family:Verdana;&...<span style="font-family:;" "=""><span style="font-family:Verdana;">In this paper, it was introduced that </span><i><span style="font-family:Verdana;">Coix lacryma-jobi</span></i><span style="font-family:Verdana;"> is a traditional dual-</span></span><span style="font-family:;" "=""><span style="font-family:Verdana;">use edible and medicine crops in China, and the nutritional components and medicinal value of </span><i><span style="font-family:Verdana;">Coix lacryma-jobi</span></i><span style="font-family:Verdana;"> were described. Based on the published literature at home and abroad, a variety of chemical components found in </span><i><span style="font-family:Verdana;">Coix lacryma jobi</span></i><span style="font-family:Verdana;"> and their medicinal effects were reviewed. At the same time,</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">the problems existing in the production of </span><i><span style="font-family:Verdana;">Coix lacryma jobi</span></i><span style="font-family:Verdana;"> were put forward. With the improvement of people’s living standards, the nutritional and health care value of </span><i><span style="font-family:Verdana;">Coix lacryma-jobi</span></i><span style="font-family:Verdana;"> has been paid more and more attention.</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">The problems of </span><i><span style="font-family:Verdana;">Coix lacryma-jobi</span></i><span style="font-family:Verdana;"> in production were analyzed.</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">Some biological characteristics of </span><i><span style="font-family:Verdana;">Coix lacryma-jobi</span></i><span style="font-family:Verdana;">, especially its hygrophyte characteristics, were re-recognized, which is very important to increase the yield of </span><i><span style="font-family:Verdana;">Coix lacryma jobi</span></i><span style="font-family:Verdana;">. In the paper, the key cultivation techniques for high and stable yield of </span><i><span style="font-family:Verdana;">Coix lacryma-jobi</span></i><span style="font-family:Verdana;"> were also summarized. In order to obtain high quality, high and stable yield, we should adopt the new technical methods of “two wet, two dry and two water” in water management. At </span></span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">same time, if artificial pollination is applied in the peak of flowering period, the seed setting rate and the yield will be increased.</span>展开更多
This paper analyzes and studies the problems of frequent system crash, high internal cremation rate and low efficiency in the electric dust control room of Liaoning Diaobingshan Gangue Power Generation Co., Ltd., upgr...This paper analyzes and studies the problems of frequent system crash, high internal cremation rate and low efficiency in the electric dust control room of Liaoning Diaobingshan Gangue Power Generation Co., Ltd., upgrades the control system, replaces the rapping beam, adjusts the spacing between the substrate and the pole line, and increases the efficiency of electric dust removal. At the same time, it can save energy and reduce consumption.展开更多
We investigate strong stability preserving(SSP)implicit-explicit(IMEX)methods for partitioned systems of differential equations with stiff and nonstiff subsystems.Conditions for order p and stage order q=p are derived...We investigate strong stability preserving(SSP)implicit-explicit(IMEX)methods for partitioned systems of differential equations with stiff and nonstiff subsystems.Conditions for order p and stage order q=p are derived,and characterization of SSP IMEX methods is provided following the recent work by Spijker.Stability properties of these methods with respect to the decoupled linear system with a complex parameter,and a coupled linear system with real parameters are also investigated.Examples of methods up to the order p=4 and stage order q—p are provided.Numerical examples on six partitioned test systems confirm that the derived methods achieve the expected order of convergence for large range of stepsizes of integration,and they are also suitable for preserving the accuracy in the stiff limit or preserving the positivity of the numerical solution for large stepsizes.展开更多
In this study,we successfully designed and synthesized a pyridine-modified tris(2,4,6-trichlorophenyl)methyl radical(PyTTM).PyTTM exhibited notably rapid single-crystal formation in acetone.Single-crystal X-ray analys...In this study,we successfully designed and synthesized a pyridine-modified tris(2,4,6-trichlorophenyl)methyl radical(PyTTM).PyTTM exhibited notably rapid single-crystal formation in acetone.Single-crystal X-ray analysis revealed that molecular planarity and multidimensional intermolecular non-covalent interactions were key factors driving its fast crystallization.Compared to TTM,PyTTM showed significantly enhanced photostability.The introduction of the pyridine group endowed PyTTM with reversible acid-base responsiveness and excellent cycling stability.Furthermore,the triangular radical ligand was able to self-assemble with temed-Pd(NO_(3))_(2) into a one-dimensional macrocyclic chain.This work offers a promising design strategy for novel luminescent radicals that combine high stability,rapid crystallization,and acid-base stimulus responsiveness.展开更多
The vertical sections of the La−Fe−B system were investigated using electron probe microanalysis and differential thermal analysis.Based on the microstructures and phase compositions of the as-cast and equilibrium all...The vertical sections of the La−Fe−B system were investigated using electron probe microanalysis and differential thermal analysis.Based on the microstructures and phase compositions of the as-cast and equilibrium alloys,together with their heat flow−temperature curves,phase diagrams for three vertical sections were drawn:La_(x)Fe_(82)B_(y)(x+y=18),La_(x)Fe_(70)B_(y)(x+y=30)and La_(x)Fe_(53)B_(y)(x+y=47),where x and y represent mass fraction of La and B,respectively,%.Additionally,according to the phase diagrams,the compound La2Fe14B was identified as a stable phase at high temperatures.It was found to be stable between 926.2 and 792.6℃;at low temperatures,however,it decomposed into α-La,α-Fe and LaFe_(4)B_(4),according to the reaction La_(2)Fe_(14)B→α-Fe+α-La+LaFe_(4)B_(4).展开更多
The ternary-element storage and flow concept for shale oil reservoirs in Jiyang Depression of Bohai Bay Basin,East China,was proposed based on the data of more than 10000 m cores and the production of more than 60 hor...The ternary-element storage and flow concept for shale oil reservoirs in Jiyang Depression of Bohai Bay Basin,East China,was proposed based on the data of more than 10000 m cores and the production of more than 60 horizontal wells.The synergy of three elements(storage,fracture and pressure)contributes to the enrichment and high production of shale oil in Jiyang Depression.The storage element controls the enrichment of shale oil;specifically,the presence of inorganic pores and fractures,as well as laminae of lime-mud rocks,in the saline lake basin,is conducive to the storage of shale oil,and the high hydrocarbon generating capacity and free hydrocarbon content are the material basis for high production.The fracture element controls the shale oil flow;specifically,natural fractures act as flow channels for shale oil to migrate and accumulate,and induced fractures communicate natural fractures to form complex fracture network,which is fundamental to high production.The pressure element controls the high and stable production of shale oil;specifically,the high formation pressure provides the drive force for the migration and accumulation of hydrocarbons,and fracturing stimulation significantly increases the elastic energy of rock and fluid,improves the imbibition replacement of oil in the pores/fractures,and reduces the stress sensitivity,guaranteeing the stable production of shale oil for a long time.Based on the ternary-element storage and flow concept,a 3D development technology was formed,with the core techniques of 3D well pattern optimization,3D balanced fracturing,and full-cycle optimization of adjustment and control.This technology effectively guides the production and provides a support to the large-scale beneficial development of shale oil in Jiyang Depression.展开更多
A recent research reports on chip-fiber-chip quantum teleportation of time-bin-encoded qubits over a 12.3 km optical fiber link within a star-topology quantum network,composed of an on-chip accommodated user node,rela...A recent research reports on chip-fiber-chip quantum teleportation of time-bin-encoded qubits over a 12.3 km optical fiber link within a star-topology quantum network,composed of an on-chip accommodated user node,relay node and a central node.An active feedback optimization scheme is embedded to ensure highly stable Bell state measurements.展开更多
The growing demand for surface-enhanced Raman scattering sensors in biochemical detection,environmental monitoring,microfluidics,and other fields has promoted the development of highly sensitive and stable substrates....The growing demand for surface-enhanced Raman scattering sensors in biochemical detection,environmental monitoring,microfluidics,and other fields has promoted the development of highly sensitive and stable substrates.Femtosecond laser-fabricated surfaces with controlled wettability,unique micro/nanostructure designs,and tunable extreme wetting properties can significantly enhance the signal amplification and reproducibility of surface-enhanced Raman scattering techniques.In this review,we offer a comprehensive overview of recent advancements in surface-enhanced Raman scattering techniques based on superwetting surfaces fabricated by femtosecond laser processing,including fully superhydrophobic surfaces,hybrid wettability surfaces,and visual localization surfaces.The main research areas,such as pattern optimization,dynamic measurements,hot spot enhancement,and stability improvement,are highlighted.We also summarize the practical applications of surface-enhanced Raman scattering in chemical detection,microfluidic control,medical diagnosis,and food safety evaluation.Finally,the current challenges and limitations in the development of femtosecond laser-processed superwetting substrates for surface-enhanced Raman scattering are described.展开更多
The design and synthesis of stable metal–organic frameworks(MOFs)have been a core obstacle in the widespread application of these functional crystalline porous materials,because of the stability limitations of MOFs u...The design and synthesis of stable metal–organic frameworks(MOFs)have been a core obstacle in the widespread application of these functional crystalline porous materials,because of the stability limitations of MOFs under harsh operating conditions.Herein,a highly stable microporous MOF based on the Fe_(3)O cluster(PCN-678)has been synthesized using a tetracarboxylate ligand.Utilizing symmetry reduced tetratopic carboxylate ligand,a mesoporous MOF(PCN-668)could be obtained in which nanoscale cage-like building units and one-dimensional(1D)channels coexist.The neighboring cages were mutual diastereomers in PCN-668 due to the further reduction of the Cs symmetry of the free ligand to C1 symmetry after self-assembly.Furthermore,the acid stability of this mesoporous MOF was improved via postsynthetic metal exchange to chromium(PCN-668-Cr).The PCN-668-Cr exhibited very high stability in both acidic and basic aqueous solutions(pH=1–11).Additionally,the mesoporous MOF showed a high total gravimetric methane uptake(∼500 cm^(3) g^(−1) at 100 bar),while the microporous MOF showed a high volumetric methane storage capacity of 147 cm3 cm−3 at room temperature.展开更多
文摘We demonstrate a home-built electrochemical scanning tunneling microscope （ECSTM）. The ECSTM exhibits highly stable performance. The drifting rates in XY and Z directions of the ECSTM are about 67 and 55.6 pm/min, respectively. Moreover, a specially designed scanner unit successfully solves the well-known problem of large leakage current in high humidity atmosphere. The mechanical structure of the ECSTM is described in detail. The excellent performances of the system are demonstrated by the measured STM images （in copper sulfate solution）, including clean and well-ordered large area morphology of Au（111） and the atomically resolved image of highly oriented pyrolytic graphite.
基金support from the National Natural Science Foundation of China(grant no.51902184)the Shandong Provincial Natural Science Foundation(grant no.ZR2019BEM028)+2 种基金the“Qi-Lu Young Scholar Fund”(grant no.31370088963167)from Shandong Universitysupport from the Major Basic Research Projects of Shandong Natural Science Foundation(ZR2018ZB0104)supported by the National Natural Science Foundation of China(grant no.21805111)and the Taishan Scholar Fund.
文摘Bismuth-based fluoride nanocrystalline materials are an emerging class of host matrixes for luminescent ions with promising applications in optoelectronic devices and medical diagnosis.However,rapid aqueous-phase synthesis of highly stable bismuth-based fluoride nanocrystals at low temperature(room temperature∼90℃)is still a significant challenge.Herein we report an ultrafast(1 min only)and economical aqueous method to synthesize lanthanide-doped K_(0.3)Bi_(0.7)F_(2.4)upconversion nanocrystalline particles at low temperature.The resultant materials show exceptional upconversion luminescence performance under the excitation of a 980 nm near-infrared laser.More importantly,these fluoride nanocrystalline particles show excellent stability against high temperature up to 200℃,high excitation power density(80 W cm^(−2))and prolonged water soaking(60 days or more).The proposed simple synthesis route,rare-earth free fluoride matrix,commendable upconversion luminescence performance and excellent chemical and thermal stability opens the door to access these lanthanide-doped K0.3Bi0.7F2.4 upconversion nanocrystalline particles for anti-counterfeiting and other daily applications.
基金This work was supported by the National Natural Science Foundation of China(Nos.51772162,22001143,and 52072197)Youth Innovation and Technology Foundation of Shandong Higher Education Institutions,China(No.2019KJC004)+4 种基金Outstanding Youth Foundation of Shandong Province,China(No.ZR2019JQ14)Taishan Scholar Young Talent Program,China(Nos.tsqn201909114 and tsqn201909123)Natural Science Foundation of Shandong Province,China(No.ZR2020YQ34)Major Scientific and Technological Innovation Project,China(No.2019JZZY020405)Major Basic Research Program of Natural Science Foundation of Shandong Province,China(No.ZR2020ZD09).
文摘Coordination engineering can enhance the activity and stability of the catalyst in heterogeneous catalysis.However,the axial coordination engineering between different groups on the carbon carrier and molecular catalysts in the electrocatalytic carbon dioxide reduction reaction(CO_(2)RR)has been studied rarely.Through coordination engineering strategy,a series of amino(NH_(2)),hydroxyl(OH),and carboxyl(COOH)groups functionalized carbon nanotubes(CNT)immobilized cobalt phthalocyanine(CoPc)catalysts are designed.Compared with no groups,OH groups and COOH groups,NH_(2)groups can effectively change the coordination environment of the central metal Co,thereby significantly increasing the turnover frequency(TOF)(31.4 s^(-1)at-0.6 V vs.RHE,CoPc/NH_(2)-CNT>CoPc/OH-CNT>CoPc/COOH-CN>CoPc/CNT).In the flow cell,the CoPc/NH_(2)-CNT catalyst has high carbon monoxide(CO)selectivity at high current density(~100%at-225 mA·cm^(-2),~96%at-351 mA·cm^(-2)).Importantly,the CoPc/NH_(2)-CNT catalyst can operate stably for 100 h at 225 mA·cm^(-2).Theoretical calculations reveal that CoPc/NH_(2)-CNT catalyst is beneficial to the formation of^(*)COOH and desorption of^(*)CO,thus promoting CO_(2)RR.This work provides an excellent platform for understanding the effect of coordination engineering on electrocatalytic performance and promotes a way to explore efficient and stable catalysts in other applications.
基金supported by the National Natural Science Foundation of China(Nos.11574397,61775238,61705262,and 61705263)the Scientific Research Project of National University of Defense Technology(No.JC15-11-02)
文摘We modify the pulse-reference-based compensation technique and propose a low-noise and highly stable optical fiber temperature sensor based on a zinc telluride film-coated fiber tip. The system noise is measured to be 0.0005 dB, which makes it possible for the detection of the minor reflectivity change of the film at different temperatures. The temperature sensitivity is 0.0034 d B/℃, so the resolution can achieve 0.2℃. The maximum difference of the temperature output values of the sensor at 20℃ at different points in time is 0.39℃. The low cost, ultra-small size, high stability, and good repeatability of the sensor make it a promising temperature sensing device for practical application.
基金funding support from the Natural Science Foundation of Shanghai(23ZR1443900)National Natural Science Foundation of China(Grant No.22109098).
文摘The development of economical and stable catalyst electrodes for industrial-scale seawater splitting is one of the cur-rent challenges in hydrogen production.The economical transition metals possess high electrical conductivity and offer the potential for designing electrodes with high intrinsic activity through appropriate modifications,thus holding promising applications in industrial contexts.Herein,a durable and economical self-supported bifunctional electrode(Fe@Ni)with high efficiency and large area is successfully constructed by one step in-situ deposition of iron on the porous structure of nickel foam(NF)via mild(298 K)electroplating method.Transition metals like iron and nickel offer high electrical conductivity and can be properly modified to achieve electrodes with high intrinsic activity.Due to the in-situ growth of cost-effective iron on the NF surface,the electrode surface morphology and electronic structure are reconstructed,which significantly improves the electrochemical activity surface area and electron transfer capabil-ity of the electrode.The hydrogen/oxygen evolution reaction(HER/OER)in simulated seawater(1 M KOH+0.5 M NaCl)require only 129 mV and 323 mV overpotentials to achieve a current density of 100 mA cm^(-2).Overall seawater splitting(OWS)achieves 10 mA cm^(-2) at a low voltage of 1.49 V and with a faradaic efficiency of nearly 100%.More importantly,the bifunctional electrodes remain stable at industrial-level current density(1.0 A cm^(-2))for more than 50 days.More attractively,this work realizes the universal construction of large-area electrode for multiple metals(e.g.,Fe,Cu,Al,etc.)with mild and simple process,which provides a new strategy for the current research of energy and materials.
基金the financial support from the Foshan Talents Special Foundation(BKBS202003).
文摘Unstable Zn interface caused by rampant dendrite growth and parasitic side reactions always hinders the practical application of aqueous zinc metal batteries(AZMBs),Herein,tyrosine(Tyr)with high molecular polarity was introduced into aqueous electrolyte to modulate the interfacial electrochemistry of Zn anode.In AZMBs,the positively charged side of Tyr can be well adsorbed on the surface of Zn anode to form a water-poor layer,and the exposed carboxylate side can be easily coordinated with Zn^(2+),favoring inducing uniform plating of Zn^(2+)and inhibiting the occurrence of water-induced side reactions.These in turn enable the achievement of highly stable Zn anode.Accordingly,the Zn anodes achieve outstanding cyclic stability(3000 h at 2 mA cm^(-2),2 mA h cm^(-2)and 1300 h at 5 mA cm^(-2),5 mA h cm^(-2)),high average Coulombic efficiency(99.4%over 3200 cycles),and high depth of discharge(80%for 500 h).Besides,the assembled Zn‖NaV_(3)O_(8)·1.5H_(2)O full cells deliver remarkable capacity retention and ultra-long lifetime(61.8%over 6650 cycles at 5 A g^(-1))and enhanced rate capability(169 mA h g^(-1)at 5 A g^(-1)).The work may promote the design and deep understanding of electrolyte additives with high molecular polarity for high-performance AZMBs.
基金Supported by the National Natural Science Foundation of China under Grant No 91441201
文摘Highly efficient and stable hybrid white organic light-emitting diodes （HWOLEDs） with a mixed bipolar interlayer between fluorescent blue and phosphorescent yellow emitting layers are demonstrated. The bipolar interlayer is a mixture of p-type diphenyl （l0-phenyl-lOH-spiro [acridine-9,9＇-fluoren]-3Lyl） phosphine oxide and n-type 2＇,2- （1,3,5-benzinetriyl）-tris（1-phenyl-l-H-benzimidazole）. The electroluminance and Commission Internationale de l＇Eclairage （CIE1931） coordinates＇ characteristics can be modulated easily by adjusting the ratio of the hole- predominated material to the electron-predominated material in the interlayer. The hybrid WOLED with a p-type：n-type ratio of 1：3 shows a maximum current efficiency and power efficiency of 61.1 ed/A and 55.8 lm/W, respectively, with warm white CIE coordinates of （0.34, 0.43）. The excellent efficiency and adaptive CIE coordi- nates are attributed to the mixed interlayer with improved charge carrier balance, optimized exciton distribution, and enhanced harvesting of singlet and triplet excitons.
基金supported by the National Key R&D Program of China(No.2022YFB3805302)the National Natural Science Foundation of China(No.22379141)+2 种基金CAS Strategic Leading Science&Technology Program(A)(No.XDA0400201)Dalian Science and Technology Star Program(No.2022RQ014)Youth Innovation Promotion Association CAS(No.2022184).
文摘The membrane,one of the key components of flow batteries,ideally has high selectivity,conductivity,and stability.However,porous membranes prepared by conventional non-solvent-induced phase separation(NIPS)commonly suffer from low selectivity and poor mechanical stability.Here,we used rigid naphthalene-containing polybenzimidazole(NPBI)to prepare a porous membrane with unique egg-shaped pores by adjusting solvent/non-solvent exchange in NIPS.The dense pores with a size of 3.6Åarranged dispersedly between egg-shaped pores.The rigid NPBI and 3.6-Åsmall pores enabled the membrane high mechanical strength.The thickness was thus decreased to 1.4μm,which exhibited an ultrahigh tensile strength of 463.54 MPa.The dense pores were also smaller than hydrated vanadium ions,achieving a low permeability of 2.28×10^(-7)cm^(2)/h,indicating high selectivity.This is the first time to prepare such a highly selective and mechanically stable ultrathin porous membrane by NIPS.Importantly,the ion-transport pathways in the 1.4μm membrane were shortened,decreasing the area resistance to as low as 0.015Ωcm 2.Demonstrated in a vanadium flow battery,its coulombic efficiency was 98.57%and energy efficiency reached 81.72%at 200 mA/cm 2.This study proposes an effective strategy to prepare highperformance ultrathin porous membranes for flow batteries.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61420106002,51373189,61178061,and 61227008the Hundred Talents Program of the Chinese Academy of Sciences,the National Basic Research Program of China under Grant No 2014CB932600the Start-Up Fund of the Technical Institute of Physics and Chemistry of the Chinese Academy of Sciences
文摘High efficiency, stable organic light-emitting diodes （OLEDs） based on 2-pheyl-4＇-carbazole-9-H-Thioxanthen-9- one-10, 10-dioxide （TXO-PhCz） with different doping concentration are constructed. The stability of the encap- sulated devices are investigated in detail. The devices with the 10 wt% doped TXO-PhCz emitter layer （EML） show the best performance with a current efficiency of 52.1 cd/A, a power efficiency of 32.71re^W, and an external quantum efficiency （EQE） of 17.7%. The devices based on the lOwt%-doped TXO-PhCz EML show the best operational stability with a half-life time （LTSO） of 8Oh, which is 8 h longer than that of the reference devices based on fac-tris（2-phenylpyridinato）iridium（ Ⅲ） （Ir（ppy）a）. These indicate excellent stability of TXO-PhCz for redox and oxidation processes under electrical excitation and TXO-PhCz can be potentially used as the emitters for OLEDs with high efficiency and excellent stability. The high-performance device based on TXO-PhCz with high stability can be further improved by the optimization of the encapsulation technology and the development of a new host for TXO-PhCz.
文摘This paper mainly introduces an output control method with high stable precision of a large power IGBT arc welding inverter. Experiments indicate that this kind of control mode can effectively improve the static and dynamic characteristics and stability of power supply system. And it can decrease the spatters in the welding process apparently. This power supply is especially suitable to automatic robot welding assembly line. It will be the developing direction of robot welding supply in the future.
文摘<span style="font-family:;" "=""><span style="font-family:Verdana;">In this paper, it was introduced that </span><i><span style="font-family:Verdana;">Coix lacryma-jobi</span></i><span style="font-family:Verdana;"> is a traditional dual-</span></span><span style="font-family:;" "=""><span style="font-family:Verdana;">use edible and medicine crops in China, and the nutritional components and medicinal value of </span><i><span style="font-family:Verdana;">Coix lacryma-jobi</span></i><span style="font-family:Verdana;"> were described. Based on the published literature at home and abroad, a variety of chemical components found in </span><i><span style="font-family:Verdana;">Coix lacryma jobi</span></i><span style="font-family:Verdana;"> and their medicinal effects were reviewed. At the same time,</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">the problems existing in the production of </span><i><span style="font-family:Verdana;">Coix lacryma jobi</span></i><span style="font-family:Verdana;"> were put forward. With the improvement of people’s living standards, the nutritional and health care value of </span><i><span style="font-family:Verdana;">Coix lacryma-jobi</span></i><span style="font-family:Verdana;"> has been paid more and more attention.</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">The problems of </span><i><span style="font-family:Verdana;">Coix lacryma-jobi</span></i><span style="font-family:Verdana;"> in production were analyzed.</span></span><span style="font-family:;" "=""> </span><span style="font-family:;" "=""><span style="font-family:Verdana;">Some biological characteristics of </span><i><span style="font-family:Verdana;">Coix lacryma-jobi</span></i><span style="font-family:Verdana;">, especially its hygrophyte characteristics, were re-recognized, which is very important to increase the yield of </span><i><span style="font-family:Verdana;">Coix lacryma jobi</span></i><span style="font-family:Verdana;">. In the paper, the key cultivation techniques for high and stable yield of </span><i><span style="font-family:Verdana;">Coix lacryma-jobi</span></i><span style="font-family:Verdana;"> were also summarized. In order to obtain high quality, high and stable yield, we should adopt the new technical methods of “two wet, two dry and two water” in water management. At </span></span><span style="font-family:Verdana;">the </span><span style="font-family:Verdana;">same time, if artificial pollination is applied in the peak of flowering period, the seed setting rate and the yield will be increased.</span>
文摘This paper analyzes and studies the problems of frequent system crash, high internal cremation rate and low efficiency in the electric dust control room of Liaoning Diaobingshan Gangue Power Generation Co., Ltd., upgrades the control system, replaces the rapping beam, adjusts the spacing between the substrate and the pole line, and increases the efficiency of electric dust removal. At the same time, it can save energy and reduce consumption.
文摘We investigate strong stability preserving(SSP)implicit-explicit(IMEX)methods for partitioned systems of differential equations with stiff and nonstiff subsystems.Conditions for order p and stage order q=p are derived,and characterization of SSP IMEX methods is provided following the recent work by Spijker.Stability properties of these methods with respect to the decoupled linear system with a complex parameter,and a coupled linear system with real parameters are also investigated.Examples of methods up to the order p=4 and stage order q—p are provided.Numerical examples on six partitioned test systems confirm that the derived methods achieve the expected order of convergence for large range of stepsizes of integration,and they are also suitable for preserving the accuracy in the stiff limit or preserving the positivity of the numerical solution for large stepsizes.
基金funded by National Nature Science Foundation of China(No.22422105)M.W.acknowledges the ECNU Academic Innovation Promotion Program for Excellent Doctoral Students(YBNLTS2024-005)。
文摘In this study,we successfully designed and synthesized a pyridine-modified tris(2,4,6-trichlorophenyl)methyl radical(PyTTM).PyTTM exhibited notably rapid single-crystal formation in acetone.Single-crystal X-ray analysis revealed that molecular planarity and multidimensional intermolecular non-covalent interactions were key factors driving its fast crystallization.Compared to TTM,PyTTM showed significantly enhanced photostability.The introduction of the pyridine group endowed PyTTM with reversible acid-base responsiveness and excellent cycling stability.Furthermore,the triangular radical ligand was able to self-assemble with temed-Pd(NO_(3))_(2) into a one-dimensional macrocyclic chain.This work offers a promising design strategy for novel luminescent radicals that combine high stability,rapid crystallization,and acid-base stimulus responsiveness.
基金financially supported by the Natural Science Foundation of China(No.51761007)the Guangxi Natural Science Foundation,China(Nos.2019GXNSFAA245003,2018GXNSFAA294069,2020GXNSFFA297004,2021GXNSFDA075009)+5 种基金the Guangxi Project of Science and Technology,China(Nos.AD19110078,AA18242023-1)the Scientific Research Foundation of Guilin University of Electronic Technology,China(No.UF18016)the Guangxi Key Laboratory of Processing for Non-ferrous Metals and Featured Materials(No.2019GXYSOF08),Chinathe Guangxi Key Laboratory of Information Materials,China(No.191012-Z)the National Key R&D Program of China(No.2016YFB0700901)financial support from the foundation for Guangxi Bagui scholars,China。
文摘The vertical sections of the La−Fe−B system were investigated using electron probe microanalysis and differential thermal analysis.Based on the microstructures and phase compositions of the as-cast and equilibrium alloys,together with their heat flow−temperature curves,phase diagrams for three vertical sections were drawn:La_(x)Fe_(82)B_(y)(x+y=18),La_(x)Fe_(70)B_(y)(x+y=30)and La_(x)Fe_(53)B_(y)(x+y=47),where x and y represent mass fraction of La and B,respectively,%.Additionally,according to the phase diagrams,the compound La2Fe14B was identified as a stable phase at high temperatures.It was found to be stable between 926.2 and 792.6℃;at low temperatures,however,it decomposed into α-La,α-Fe and LaFe_(4)B_(4),according to the reaction La_(2)Fe_(14)B→α-Fe+α-La+LaFe_(4)B_(4).
基金Supported by Sinopec Key Science and Technology Research Project(P21060)。
文摘The ternary-element storage and flow concept for shale oil reservoirs in Jiyang Depression of Bohai Bay Basin,East China,was proposed based on the data of more than 10000 m cores and the production of more than 60 horizontal wells.The synergy of three elements(storage,fracture and pressure)contributes to the enrichment and high production of shale oil in Jiyang Depression.The storage element controls the enrichment of shale oil;specifically,the presence of inorganic pores and fractures,as well as laminae of lime-mud rocks,in the saline lake basin,is conducive to the storage of shale oil,and the high hydrocarbon generating capacity and free hydrocarbon content are the material basis for high production.The fracture element controls the shale oil flow;specifically,natural fractures act as flow channels for shale oil to migrate and accumulate,and induced fractures communicate natural fractures to form complex fracture network,which is fundamental to high production.The pressure element controls the high and stable production of shale oil;specifically,the high formation pressure provides the drive force for the migration and accumulation of hydrocarbons,and fracturing stimulation significantly increases the elastic energy of rock and fluid,improves the imbibition replacement of oil in the pores/fractures,and reduces the stress sensitivity,guaranteeing the stable production of shale oil for a long time.Based on the ternary-element storage and flow concept,a 3D development technology was formed,with the core techniques of 3D well pattern optimization,3D balanced fracturing,and full-cycle optimization of adjustment and control.This technology effectively guides the production and provides a support to the large-scale beneficial development of shale oil in Jiyang Depression.
文摘A recent research reports on chip-fiber-chip quantum teleportation of time-bin-encoded qubits over a 12.3 km optical fiber link within a star-topology quantum network,composed of an on-chip accommodated user node,relay node and a central node.An active feedback optimization scheme is embedded to ensure highly stable Bell state measurements.
基金National Natural Science Foundation of China,Grant/Award Number:6240032084Natural Science Foundation of Shaanxi Province,Grant/Award Number:2023-JC-QN-0711+1 种基金Fundamental Research Funds for the Central Universities111 Project。
文摘The growing demand for surface-enhanced Raman scattering sensors in biochemical detection,environmental monitoring,microfluidics,and other fields has promoted the development of highly sensitive and stable substrates.Femtosecond laser-fabricated surfaces with controlled wettability,unique micro/nanostructure designs,and tunable extreme wetting properties can significantly enhance the signal amplification and reproducibility of surface-enhanced Raman scattering techniques.In this review,we offer a comprehensive overview of recent advancements in surface-enhanced Raman scattering techniques based on superwetting surfaces fabricated by femtosecond laser processing,including fully superhydrophobic surfaces,hybrid wettability surfaces,and visual localization surfaces.The main research areas,such as pattern optimization,dynamic measurements,hot spot enhancement,and stability improvement,are highlighted.We also summarize the practical applications of surface-enhanced Raman scattering in chemical detection,microfluidic control,medical diagnosis,and food safety evaluation.Finally,the current challenges and limitations in the development of femtosecond laser-processed superwetting substrates for surface-enhanced Raman scattering are described.
基金supported by the Center for Gas Separations,an Energy Frontier Research Center funded by the U.S.Department of Energy,Office of Science,Office of Basic Energy Sciences(no.DESC0001015)Structural analyses were supported by the Robert A.Welch Foundation through a Welch Endowed Chair to H.-C.Z.(A-0030)+3 种基金The National Science Foundation Graduate Research Fellowship(DGE:1252521)is gratefully acknowledged.The authors also acknowledge the financial support of the U.S.Department of Energy Office of Fossil Energy,National Energy Technology Laboratory(no.DE-FE0026472)and National Science Foundation Small Business Innovation Research(NSFSBIR)under grant no.(1632486)the financial support of the Strategic Priority Research Program of the Chinese Academy of Sciences(no.XDB20000000)National Nature Science Foundation of China(no.21871266),CAS(no.QYZDY-SSWSLH025),and Youth Innovation Promotion Association CAS.
文摘The design and synthesis of stable metal–organic frameworks(MOFs)have been a core obstacle in the widespread application of these functional crystalline porous materials,because of the stability limitations of MOFs under harsh operating conditions.Herein,a highly stable microporous MOF based on the Fe_(3)O cluster(PCN-678)has been synthesized using a tetracarboxylate ligand.Utilizing symmetry reduced tetratopic carboxylate ligand,a mesoporous MOF(PCN-668)could be obtained in which nanoscale cage-like building units and one-dimensional(1D)channels coexist.The neighboring cages were mutual diastereomers in PCN-668 due to the further reduction of the Cs symmetry of the free ligand to C1 symmetry after self-assembly.Furthermore,the acid stability of this mesoporous MOF was improved via postsynthetic metal exchange to chromium(PCN-668-Cr).The PCN-668-Cr exhibited very high stability in both acidic and basic aqueous solutions(pH=1–11).Additionally,the mesoporous MOF showed a high total gravimetric methane uptake(∼500 cm^(3) g^(−1) at 100 bar),while the microporous MOF showed a high volumetric methane storage capacity of 147 cm3 cm−3 at room temperature.
