Hydrogen production from electrochemical water splitting is a promising strategy to generate green energy,which requires the development of efficient and stable electrocatalysts for the hydrogen evolution reaction and...Hydrogen production from electrochemical water splitting is a promising strategy to generate green energy,which requires the development of efficient and stable electrocatalysts for the hydrogen evolution reaction and the oxygen evolution reaction(HER and OER).Ionic liquids(ILs)or poly(ionic liquids)(PILs),containing heteroatoms,metal-based anions,and various structures,have been frequently involved as precursors to prepare electrocatalysts for water splitting.Moreover,ILs/PILs possess high conductivity,wide electrochemical windows,and high thermal and chemical stability,which can be directly applied in the electrocatalysis process with high durability.In this review,we focus on the studies of ILs/PILs-derived electrocatalysts for HER and OER,where ILs/PILs are applied as heteroatom dopants and metal precursors to prepare catalysts or are directly utilized as the electrocatalysts.Due to those attractive properties,IL/PIL-derived electrocatalysts exhibit excellent performance for electrochemical water splitting.All these accomplishments and developments are systematically summarized and thoughtfully discussed.Then,the overall perspectives for the current challenges and future developments of ILs/PILs-derived electrocatalysts are provided.展开更多
Polyethylene terephthalate (PET) as one of non-degradable wastes has become a huge threat to the environment and human health.Chemical Recycle of PET is a sustainable way to release 1,4-benzenedicarboxylic acid (BDC) ...Polyethylene terephthalate (PET) as one of non-degradable wastes has become a huge threat to the environment and human health.Chemical Recycle of PET is a sustainable way to release 1,4-benzenedicarboxylic acid (BDC) the monomer of PET as common used organiclinker for synthesis of functional Metal–organic-frameworks (PET-derived MOFs) such as UiO-66, MIL-101, etc. This sustainable and costeffective“Waste-to-MOFs” model is of great significant to be intensively investigated in the past years. Attributes of substantial porosity, specificsurface area, exposed metal centers, uniform structure, and flexible morphology render PET-derived MOFs are well-suited for applications inadsorption, energy storage, catalysis, among others. Herein, in the present work, we have summarized recent advances in synthesis of PETderived MOFs using ex-situ and in-situ methods for typical applications of adsorption, catalysis and energy storage. Despite those improvementsin synthesis methods and potential applications, challenges still remain in development of green and economical routes to fully utilize waste PETfor massive manufacture of valuable MOF materials and chemicals. This review provides insights into the conversion of non-degradable PETwaste to value-added MOF materials, and further suggests promising perspectives to develop the sustainable “Waste-to-MOFs” model inaddressing environmental pollution and energy crises.展开更多
Objective: To explore the application effect of oral glucose combined with short-term intravenous nutrition in preventing postoperative hypoglycemia after painless endoscopic gastric polyp resection, and to provide gu...Objective: To explore the application effect of oral glucose combined with short-term intravenous nutrition in preventing postoperative hypoglycemia after painless endoscopic gastric polyp resection, and to provide guidance for better management of patients undergoing such procedures. Methods: A total of 886 patients who underwent painless endoscopic gastric polyp resection in the Department of Gastroenterology, the First Affiliated Hospital of Yangtze University, from January 2020 to December 2021, were selected as the study subjects. According to the random number table method, they were divided into an experimental group and a control group, with 443 cases in each group. Patients in the control group were subjected to routine fasting and water restriction for 8 hours before surgery, and routine fasting for 24 hours after surgery. Short-term intravenous nutrition support was provided through fluid supplementation, and finger blood glucose levels were monitored at 1 hour, 4 hours, and 8 hours after completion of intravenous infusion, or when symptoms such as palpitations and cold sweats occurred. The experimental group received oral administration of 5% glucose solution (500 ml) 2 hours before surgery based on the procedures of the control group. The incidence of preoperative discomfort (hunger, thirst, and fatigue), residual gastric fluid volume, and postoperative hypoglycemia were compared between the two groups. Results: The incidence of postoperative blood glucose Conclusion: Based on the study population, oral glucose combined with short-term intravenous nutrition can effectively prevent the incidence of hypoglycemia in patients undergoing painless endoscopic gastric polyp resection. However, due to the limitations of a single-center study and a small number of cases, its feasibility needs to be further validated with more data from multi-center and large-sample cases.展开更多
Objective: To investigate the effect of oral glucose combined with short-term intravenous nutrition on the prevention of hypoglycemia after endoscopic colorectal polypectomy and to provide guidance for better manageme...Objective: To investigate the effect of oral glucose combined with short-term intravenous nutrition on the prevention of hypoglycemia after endoscopic colorectal polypectomy and to provide guidance for better management of such patients. Methods: 860 patients who underwent endoscopic colorectal polypectomy for colorectal polyps in the Department of Gastroenterology of the First Affiliated Hospital of Yangtze University from January 2020 to December 2021 were selected for the study. The patients were divided into experimental and control groups according to the random number table method, with 430 patients in each group. In the control group, 3 L of polyethylene glycol electrolyte dispersion was used for preoperative intestinal preparation and postoperative fasting was performed routinely for 24 h. Short-term intravenous nutrition support was provided by rehydration, and finger blood glucose was monitored at 1, 4, and 8 h after intravenous infusion or when there were symptoms such as panic and cold sweat;in the experimental group, oral glucose intervention was implemented on the basis of the control group. The incidence of postoperative hypoglycemia, quality of bowel preparation, and tolerance of patients during bowel preparation were compared between the 2 groups. Results: The incidence of postoperative blood glucose Conclusion: Based on the present study population, oral glucose combined with short-term intravenous nutrition can effectively prevent the incidence of hypoglycemia in patients after endoscopic colorectal polypectomy;however, this was limited to a single-center study and the number of cases was small.展开更多
Converting low-grade thermal energy into electricity through ther-mogalvanic cells offers a promising approach to addressing environ-mental challenges[1].However,thermogalvanic cells face obstacles,due to limited ther...Converting low-grade thermal energy into electricity through ther-mogalvanic cells offers a promising approach to addressing environ-mental challenges[1].However,thermogalvanic cells face obstacles,due to limited thermopower,connected to differences in solvent-dependent entropy(ΔS)among redox anions and varying concentration ratios(ΔC)between hot and cold sides[2,3].A typical strategy to enhance the thermopower involves the improvement ofΔS of the redox anions.Un-fortunately,ΔC tends to approach zero spontaneously due to the ther-modynamic instability and redox ion diffusion.Thus,the challenge is to maintain significantΔC for both redox ions and unravel the intricate modulation mechanisms[4].展开更多
Very recently,two-dimensional quantum dots(2D QDs)have been pioneeringly investigated as lubricant additives,which exhibit superior friction-reducing and wear resistance.Compared with 2D nanoparticles,2D QDs possess s...Very recently,two-dimensional quantum dots(2D QDs)have been pioneeringly investigated as lubricant additives,which exhibit superior friction-reducing and wear resistance.Compared with 2D nanoparticles,2D QDs possess small size(~10 nm)and abundant active groups.These distinguished advantages enable them to quickly disperse into common lube mediums and maintain long-term storage stability.The good dispersion stability of 2D QDs not only effectively improves their embedding capacity,but also enables continuous supplements of lubricants during the sliding process.Therefore,2D QDs are attracting increasing research interest as efficient lubricants with desirable service life.In this review,we focus on the latest studies of 2D QDs as liquid lubricant additives(both in polar and nonpolar mediums),self-lubricating solid coatings and gels,etc.Various advanced strategies for synthesis and modification of 2D QDs are summarized.A comprehensive insight into the tribological behavior of a variety of 2D QDs together with the associated mechanism is reviewed in detail.The superior lubricating performances of 2D QDs are attributed to various mechanisms,including rolling effect,self-mending performance,polishing effect,tribofilm formation,nanostructure transfer and synergistic effects,etc.Strategies for friction modulation of 2D QDs,including internal factors(surface modification,elemental doping)and extrinsic factors(counter surfaces,test conditions)are discussed,special attentions for achieving intelligent tribology toward superlubricity and bio-engineering,are also included.Finally,the future challenges and research directions regarding QDs as lubricants conforming to the concept of“green tribology”toward a sustainable society are discussed.展开更多
Based on the difference of the Y-terminal functional group of the silane coupling agent(Y-Si(X)_(3)),four different silane coupling agents were employed to pretreat the surface of the NdFeB powders.The effects of sila...Based on the difference of the Y-terminal functional group of the silane coupling agent(Y-Si(X)_(3)),four different silane coupling agents were employed to pretreat the surface of the NdFeB powders.The effects of silane coupling agents on the flowability and compressibility of compounds for preparing bonded NdFeB magnets were studied.It is indicated that compounds pretreated by silane coupling agents have weaker friction and meshing force.The apparent density is increased by 0.3 g/cm^(3 )compared with the compound without silane coupling agent,and the radial crushing strength is significantly increased by about 3-4 times.In addition,the epoxy resin is more evenly distributed on the surface of the compounds treated by silane coupling agents observed by scanning electron microscopy,and some agglomerated particles are produced.Also,the compressibility of compounds with silane coupling agents is significantly improved due to the fact that hardening exponents are reduced.However,the addition of silane coupling agents has almost no effect on the magnetic properties of bonded magnets.The special energy was used to manifest the flowability of magnetic powder particles representing the macroscopic performance of the force between powder particles,providing a new direction for the study of the interface compatibility of two-phase or multiphase composite materials.展开更多
OBJECTIVE： To observe the effect of tonifying liver and kidney-essence herbs on expression of a nerve regeneration inhibitor, Nogo for neuron A （No- go-A）, and its associated signaling molecule, low-af- finity neur...OBJECTIVE： To observe the effect of tonifying liver and kidney-essence herbs on expression of a nerve regeneration inhibitor, Nogo for neuron A （No- go-A）, and its associated signaling molecule, low-af- finity neurotrophin receptor p75 （p75TR）, in rats with cerebral ischemic stroke （CIS）, with the aim of exploring the possible mechanism of tonifying liver and kidney-essence herbs in recovery following in- jury to the central nervous system. METHODS： A cerebral ischemic stroke model in SD rats was established with the suture-occlusion method. Successful model rats were divided into placebo and herb groups at random; sham-operat- ed and control groups were set up simultaneously.Each of these groups was divided into six sub- groups at random. Expression of Nogo-A and p75TR was evaluated with immunofluorescence microsco- py at days 3, and weeks1, 2, 3, 4 and 8 after adminis- tration. RESULTS： Tonifying liver and kidney-essence herbs suppressed the expression of Nogo-A and p75T （P〈0.05 and P〈0.01, respectively）. CONCLUSION： Suppressing the expression of No- go-A and p75NTR is possibly one of the mechanisms underlying the ability of tonifying liver and kid- ney-essence herbs to promote recovery of the in- jured central nervous system.展开更多
N-Heterocyclic carbene (NHC) enabled the highly efficient catalytic hydroboration of a wide range of ketones and aldehydes under mild conditions,and a new mechanism of catalytic hydroboration reaction which involves d...N-Heterocyclic carbene (NHC) enabled the highly efficient catalytic hydroboration of a wide range of ketones and aldehydes under mild conditions,and a new mechanism of catalytic hydroboration reaction which involves direct hydride transfer is proposed.展开更多
Anisotropic NdFeB/SmFeN hybrid bonded magnets were prepared by warm compaction process under an orientation magnetic field of 22 kOe,mixing with anisotropic SmFeN powders in different addition and HDDR-NdFeB powders i...Anisotropic NdFeB/SmFeN hybrid bonded magnets were prepared by warm compaction process under an orientation magnetic field of 22 kOe,mixing with anisotropic SmFeN powders in different addition and HDDR-NdFeB powders in different coercivity.With the addition of 20 wt% SmFeN,the density and remanence of hybrid magnets increase from 5.58 g/cm~3,8.4 kGs to 6.02 g/cm~3,9.0 kGs,respectively.And as the addition amount of SmFeN powders varies from 20 wt% to 40 wt%,the maximum energy product changes less than 0.5 MGOe.In addition,the magnetization process and the interactions between two powders were studied.It is found that the magnetization process of anisotropic NdFeB powders shows distinction in different initial states.The addition of SmFeN powders promotes the rotation of NdFeB powders together with applied field,which is beneficial to the degree of alignment of NdFeB powders.Because of the micron-sized long range coupling effect,the coercivity of hybrid magnets decreases slowly with the increase of low coercivity SmFeN.Meanwhile,the magnetization process of hybrid magnets is different from pure magnets,it increases rapidly at low field and then slowly,next leads to rapidity again and achieves the saturation magnetization finally.展开更多
The significance of exosomes has emerged in a variety of physiological processes and diseases.Pancreatic cancer remains one of the most lethal diseases at present.Recently,increasing evidence has suggested that exosom...The significance of exosomes has emerged in a variety of physiological processes and diseases.Pancreatic cancer remains one of the most lethal diseases at present.Recently,increasing evidence has suggested that exosomes are vital for mediating the elaborate interaction of highly heterogeneous cell clusters within the pancreatic tumor microenvironment,contributing to activating pancreatic stellate cells and cancer-associated fibroblasts,compromising immune cells,and enhancing angiogenesis.Besides their natural and intrinsic roles,exosomes may provide a novel potential way for pancreatic cancer management and therapy as well.Thus,exosomes not only mediate cellular communication during pancreatic cancer progression but also serve as a promising player in precise pancreatic cancer management and treatment.To comprehensively summarize the role of exosomes in pancreatic cancer,we searched the PubMed database and reviewed all relevant original studies.展开更多
Chirality, as one of the ubiquitous properties in nature, has aroused striking attention in the fields of physics and materials sciences. For tailoring of light with more degree of freedom, circular dichroism has been...Chirality, as one of the ubiquitous properties in nature, has aroused striking attention in the fields of physics and materials sciences. For tailoring of light with more degree of freedom, circular dichroism has been considered as the auxiliary dimension to improving such an issue. Inspired by the Born-Kuhn plasmonic oscillation model, we demonstrate and discuss a chiral resonator to reveal reverse circular dichroism within two separate frequency bands in the microwave regime. The underlying physical mechanisms of bonding and anti-bounding modes are analyzed via transmission/reflection spectra and surface current distributions for different chiral enantiomers. To leverage the proposed paradigm to the application levels, especially for metaholography, we conduct the numerical simulation and experimental demonstration of two proofs of principles. Based on the Pancharatnam-Berry phase/amplitude modulation and complex-amplitude manipulation, respectively, the meta-holograms with independent targets of reconstructing images in full-space and reflected regions are achieved. Significantly, our paradigm may promise further applications in spin-controlled meta-devices for image processing, information encryption, anti-counterfeiting,remote sensing, and radar systems.展开更多
We investigated the coexistence of superconductivity and antiferromagnetic order in the compound Er_(2)O_(2)Bi with anti-ThCr_(2)Si_(2)-type structure through resistivity,magnetization,specific heat measurements and f...We investigated the coexistence of superconductivity and antiferromagnetic order in the compound Er_(2)O_(2)Bi with anti-ThCr_(2)Si_(2)-type structure through resistivity,magnetization,specific heat measurements and first-principle calculations.The superconducting transition temperature Tc of 1.23 K and antiferromagnetic transition temperature TN of 3 K are observed in the sample with the best nominal composition.The superconducting upper critical field H_(c2)(0)and electron-phonon coupling constantλe−ph in Er_(2)O_(2)Bi are similar to those in the previously reported non-magnetic superconductor Y_(2)O_(2)Bi with the same structure,indicating that the superconductivity in Er_(2)O_(2)Bi may have the same origin as in Y_(2)O_(2)Bi.The first-principle calculations of Er_(2)O_(2)Bi show that the Fermi surface is mainly composed of the Bi 6p orbitals both in the paramagnetic and antiferromagnetic state,implying minor effect of the 4f electrons on the Fermi surface.Besides,upon increasing the oxygen incorporation in Er_(2)O_(x)Bi,Tc increases from 1 to 1.23 K and TN decreases slightly from 3 K to 2.96 K,revealing that superconductivity and antiferromagnetic order may compete with each other.The Hall effect measurements indicate that hole-type carrier density indeed increases with increasing oxygen content,which may account for the variations of Tc and TN with different oxygen content.展开更多
The significance of exosomes has emerged in a variety of physiological processes and diseases.Pancreatic cancer remains one of the most lethal diseases at present.Recently,increasing evidence has suggested that exosom...The significance of exosomes has emerged in a variety of physiological processes and diseases.Pancreatic cancer remains one of the most lethal diseases at present.Recently,increasing evidence has suggested that exosomes are vital for mediating the elaborate interaction of highly heterogeneous cell clusters within the pancreatic tumor microenvironment,contributing to activating pancreatic stellate cells and cancer-associated fibroblasts,compromising immune cells,and enhancing angiogenesis.Besides their natural and intrinsic roles,exosomes may provide a novel potential way for pancreatic cancer management and therapy as well.Thus,exosomes not only mediate cellular communication during pancreatic cancer progression but also serve as a promising player in precise pancreatic cancer management and treatment.To comprehensively summarize the role of exosomes in pancreatic cancer,we searched the PubMed database and reviewed all relevant original studies.展开更多
An improved large signal model for InP HEMTs is proposed in this paper.The channel current and charge model equations are constructed based on the Angelov model equations.Both the equations for channel current and gat...An improved large signal model for InP HEMTs is proposed in this paper.The channel current and charge model equations are constructed based on the Angelov model equations.Both the equations for channel current and gate charge models were all continuous and high order drivable,and the proposed gate charge model satisfied the charge conservation.For the strong leakage induced barrier reduction effect of InP HEMTs,the Angelov current model equations are improved.The channel current model could fit DC performance of devices.A 2×25μm×70 nm InP HEMT device is used to demonstrate the extraction and validation of the model,in which the model has predicted the DC I–V,C–V and bias related S parameters accurately.展开更多
基金supported by the Natural Science Founda-tion of Chongqing(cstc2021jcyj-msxmX0420)Natural Science Foundation of Sichuan(2023NSFSC0088)。
文摘Hydrogen production from electrochemical water splitting is a promising strategy to generate green energy,which requires the development of efficient and stable electrocatalysts for the hydrogen evolution reaction and the oxygen evolution reaction(HER and OER).Ionic liquids(ILs)or poly(ionic liquids)(PILs),containing heteroatoms,metal-based anions,and various structures,have been frequently involved as precursors to prepare electrocatalysts for water splitting.Moreover,ILs/PILs possess high conductivity,wide electrochemical windows,and high thermal and chemical stability,which can be directly applied in the electrocatalysis process with high durability.In this review,we focus on the studies of ILs/PILs-derived electrocatalysts for HER and OER,where ILs/PILs are applied as heteroatom dopants and metal precursors to prepare catalysts or are directly utilized as the electrocatalysts.Due to those attractive properties,IL/PIL-derived electrocatalysts exhibit excellent performance for electrochemical water splitting.All these accomplishments and developments are systematically summarized and thoughtfully discussed.Then,the overall perspectives for the current challenges and future developments of ILs/PILs-derived electrocatalysts are provided.
基金supported by the National Natural Science Foundation of China(21902105,52274172)Shenzhen Science and Technology Program(JCYJ20210324094000001)Guangdong Basic and Applied Basic Research Foundation(2020A1515010471).
文摘Polyethylene terephthalate (PET) as one of non-degradable wastes has become a huge threat to the environment and human health.Chemical Recycle of PET is a sustainable way to release 1,4-benzenedicarboxylic acid (BDC) the monomer of PET as common used organiclinker for synthesis of functional Metal–organic-frameworks (PET-derived MOFs) such as UiO-66, MIL-101, etc. This sustainable and costeffective“Waste-to-MOFs” model is of great significant to be intensively investigated in the past years. Attributes of substantial porosity, specificsurface area, exposed metal centers, uniform structure, and flexible morphology render PET-derived MOFs are well-suited for applications inadsorption, energy storage, catalysis, among others. Herein, in the present work, we have summarized recent advances in synthesis of PETderived MOFs using ex-situ and in-situ methods for typical applications of adsorption, catalysis and energy storage. Despite those improvementsin synthesis methods and potential applications, challenges still remain in development of green and economical routes to fully utilize waste PETfor massive manufacture of valuable MOF materials and chemicals. This review provides insights into the conversion of non-degradable PETwaste to value-added MOF materials, and further suggests promising perspectives to develop the sustainable “Waste-to-MOFs” model inaddressing environmental pollution and energy crises.
文摘Objective: To explore the application effect of oral glucose combined with short-term intravenous nutrition in preventing postoperative hypoglycemia after painless endoscopic gastric polyp resection, and to provide guidance for better management of patients undergoing such procedures. Methods: A total of 886 patients who underwent painless endoscopic gastric polyp resection in the Department of Gastroenterology, the First Affiliated Hospital of Yangtze University, from January 2020 to December 2021, were selected as the study subjects. According to the random number table method, they were divided into an experimental group and a control group, with 443 cases in each group. Patients in the control group were subjected to routine fasting and water restriction for 8 hours before surgery, and routine fasting for 24 hours after surgery. Short-term intravenous nutrition support was provided through fluid supplementation, and finger blood glucose levels were monitored at 1 hour, 4 hours, and 8 hours after completion of intravenous infusion, or when symptoms such as palpitations and cold sweats occurred. The experimental group received oral administration of 5% glucose solution (500 ml) 2 hours before surgery based on the procedures of the control group. The incidence of preoperative discomfort (hunger, thirst, and fatigue), residual gastric fluid volume, and postoperative hypoglycemia were compared between the two groups. Results: The incidence of postoperative blood glucose Conclusion: Based on the study population, oral glucose combined with short-term intravenous nutrition can effectively prevent the incidence of hypoglycemia in patients undergoing painless endoscopic gastric polyp resection. However, due to the limitations of a single-center study and a small number of cases, its feasibility needs to be further validated with more data from multi-center and large-sample cases.
文摘Objective: To investigate the effect of oral glucose combined with short-term intravenous nutrition on the prevention of hypoglycemia after endoscopic colorectal polypectomy and to provide guidance for better management of such patients. Methods: 860 patients who underwent endoscopic colorectal polypectomy for colorectal polyps in the Department of Gastroenterology of the First Affiliated Hospital of Yangtze University from January 2020 to December 2021 were selected for the study. The patients were divided into experimental and control groups according to the random number table method, with 430 patients in each group. In the control group, 3 L of polyethylene glycol electrolyte dispersion was used for preoperative intestinal preparation and postoperative fasting was performed routinely for 24 h. Short-term intravenous nutrition support was provided by rehydration, and finger blood glucose was monitored at 1, 4, and 8 h after intravenous infusion or when there were symptoms such as panic and cold sweat;in the experimental group, oral glucose intervention was implemented on the basis of the control group. The incidence of postoperative hypoglycemia, quality of bowel preparation, and tolerance of patients during bowel preparation were compared between the 2 groups. Results: The incidence of postoperative blood glucose Conclusion: Based on the present study population, oral glucose combined with short-term intravenous nutrition can effectively prevent the incidence of hypoglycemia in patients after endoscopic colorectal polypectomy;however, this was limited to a single-center study and the number of cases was small.
基金support from the Program from Guangdong Introducing Innovative and Enterpreneurial Teams(2019ZT08L101 and RCTDPT-2020-001)the University Development Fund(UDF01001159)+4 种基金the National Natural Science Foundation of China(No.1805234,22075240,and 21972065)the Young Scientists Fund of the National Natural Science Foundation of China(No,52202306)the Shenzhen Key Laboratory of Eco-materials and Renewable Energy(ZDSYS20200922160400001)the Shenzhen Natural Science Foundation(GXWD20201231105722002-20200824163747001)the NSF of Jiangsu Province(No.BK20220006).
文摘Converting low-grade thermal energy into electricity through ther-mogalvanic cells offers a promising approach to addressing environ-mental challenges[1].However,thermogalvanic cells face obstacles,due to limited thermopower,connected to differences in solvent-dependent entropy(ΔS)among redox anions and varying concentration ratios(ΔC)between hot and cold sides[2,3].A typical strategy to enhance the thermopower involves the improvement ofΔS of the redox anions.Un-fortunately,ΔC tends to approach zero spontaneously due to the ther-modynamic instability and redox ion diffusion.Thus,the challenge is to maintain significantΔC for both redox ions and unravel the intricate modulation mechanisms[4].
基金This work was supported by the National Natural Science Foundation of China(No.52075264).
文摘Very recently,two-dimensional quantum dots(2D QDs)have been pioneeringly investigated as lubricant additives,which exhibit superior friction-reducing and wear resistance.Compared with 2D nanoparticles,2D QDs possess small size(~10 nm)and abundant active groups.These distinguished advantages enable them to quickly disperse into common lube mediums and maintain long-term storage stability.The good dispersion stability of 2D QDs not only effectively improves their embedding capacity,but also enables continuous supplements of lubricants during the sliding process.Therefore,2D QDs are attracting increasing research interest as efficient lubricants with desirable service life.In this review,we focus on the latest studies of 2D QDs as liquid lubricant additives(both in polar and nonpolar mediums),self-lubricating solid coatings and gels,etc.Various advanced strategies for synthesis and modification of 2D QDs are summarized.A comprehensive insight into the tribological behavior of a variety of 2D QDs together with the associated mechanism is reviewed in detail.The superior lubricating performances of 2D QDs are attributed to various mechanisms,including rolling effect,self-mending performance,polishing effect,tribofilm formation,nanostructure transfer and synergistic effects,etc.Strategies for friction modulation of 2D QDs,including internal factors(surface modification,elemental doping)and extrinsic factors(counter surfaces,test conditions)are discussed,special attentions for achieving intelligent tribology toward superlubricity and bio-engineering,are also included.Finally,the future challenges and research directions regarding QDs as lubricants conforming to the concept of“green tribology”toward a sustainable society are discussed.
基金Project supported by Beijing Youth Top-notch Team Support Project of China(2018000021223TD10)Hebei Province Fund for Transformation of Major Science and Technology Achievements of China(19041029Z)Hebei Province International Science and Technology Cooperation Base Construction Project of China(20591002D)。
文摘Based on the difference of the Y-terminal functional group of the silane coupling agent(Y-Si(X)_(3)),four different silane coupling agents were employed to pretreat the surface of the NdFeB powders.The effects of silane coupling agents on the flowability and compressibility of compounds for preparing bonded NdFeB magnets were studied.It is indicated that compounds pretreated by silane coupling agents have weaker friction and meshing force.The apparent density is increased by 0.3 g/cm^(3 )compared with the compound without silane coupling agent,and the radial crushing strength is significantly increased by about 3-4 times.In addition,the epoxy resin is more evenly distributed on the surface of the compounds treated by silane coupling agents observed by scanning electron microscopy,and some agglomerated particles are produced.Also,the compressibility of compounds with silane coupling agents is significantly improved due to the fact that hardening exponents are reduced.However,the addition of silane coupling agents has almost no effect on the magnetic properties of bonded magnets.The special energy was used to manifest the flowability of magnetic powder particles representing the macroscopic performance of the force between powder particles,providing a new direction for the study of the interface compatibility of two-phase or multiphase composite materials.
基金Suppored by Special Project on Traditional Chinese Medicine Science and Technology of State Administration of Traditional Chinese Medicine of the PRC(No.06-07LB21)
文摘OBJECTIVE： To observe the effect of tonifying liver and kidney-essence herbs on expression of a nerve regeneration inhibitor, Nogo for neuron A （No- go-A）, and its associated signaling molecule, low-af- finity neurotrophin receptor p75 （p75TR）, in rats with cerebral ischemic stroke （CIS）, with the aim of exploring the possible mechanism of tonifying liver and kidney-essence herbs in recovery following in- jury to the central nervous system. METHODS： A cerebral ischemic stroke model in SD rats was established with the suture-occlusion method. Successful model rats were divided into placebo and herb groups at random; sham-operat- ed and control groups were set up simultaneously.Each of these groups was divided into six sub- groups at random. Expression of Nogo-A and p75TR was evaluated with immunofluorescence microsco- py at days 3, and weeks1, 2, 3, 4 and 8 after adminis- tration. RESULTS： Tonifying liver and kidney-essence herbs suppressed the expression of Nogo-A and p75T （P〈0.05 and P〈0.01, respectively）. CONCLUSION： Suppressing the expression of No- go-A and p75NTR is possibly one of the mechanisms underlying the ability of tonifying liver and kid- ney-essence herbs to promote recovery of the in- jured central nervous system.
基金This work was supported by the National Natural Science Foundation of China (Nos. 21632006 and 21472098).
文摘N-Heterocyclic carbene (NHC) enabled the highly efficient catalytic hydroboration of a wide range of ketones and aldehydes under mild conditions,and a new mechanism of catalytic hydroboration reaction which involves direct hydride transfer is proposed.
基金supported by the National Key Research and Development Program of China (2021YFB3500202,2021YFB3500201)the Beijing Youth Top-notch Team Support Project of China (2018000021223TD10)+2 种基金the Beijing NOVA Program (Z211100002121092)the Natural Science Foundation of Hebei Province (E2021103006)the Hebei Province International Science and Technology Cooperation Base Construction Project of China (20591002D)。
文摘Anisotropic NdFeB/SmFeN hybrid bonded magnets were prepared by warm compaction process under an orientation magnetic field of 22 kOe,mixing with anisotropic SmFeN powders in different addition and HDDR-NdFeB powders in different coercivity.With the addition of 20 wt% SmFeN,the density and remanence of hybrid magnets increase from 5.58 g/cm~3,8.4 kGs to 6.02 g/cm~3,9.0 kGs,respectively.And as the addition amount of SmFeN powders varies from 20 wt% to 40 wt%,the maximum energy product changes less than 0.5 MGOe.In addition,the magnetization process and the interactions between two powders were studied.It is found that the magnetization process of anisotropic NdFeB powders shows distinction in different initial states.The addition of SmFeN powders promotes the rotation of NdFeB powders together with applied field,which is beneficial to the degree of alignment of NdFeB powders.Because of the micron-sized long range coupling effect,the coercivity of hybrid magnets decreases slowly with the increase of low coercivity SmFeN.Meanwhile,the magnetization process of hybrid magnets is different from pure magnets,it increases rapidly at low field and then slowly,next leads to rapidity again and achieves the saturation magnetization finally.
基金National Natural Science Foundation of China Grants(No.81773215,82173074)CAMS Innovation Fund for Medical Sciences(CIFMS)(No.2021-I2M-1-002).
文摘The significance of exosomes has emerged in a variety of physiological processes and diseases.Pancreatic cancer remains one of the most lethal diseases at present.Recently,increasing evidence has suggested that exosomes are vital for mediating the elaborate interaction of highly heterogeneous cell clusters within the pancreatic tumor microenvironment,contributing to activating pancreatic stellate cells and cancer-associated fibroblasts,compromising immune cells,and enhancing angiogenesis.Besides their natural and intrinsic roles,exosomes may provide a novel potential way for pancreatic cancer management and therapy as well.Thus,exosomes not only mediate cellular communication during pancreatic cancer progression but also serve as a promising player in precise pancreatic cancer management and treatment.To comprehensively summarize the role of exosomes in pancreatic cancer,we searched the PubMed database and reviewed all relevant original studies.
基金supported by the National Key Research and Development Program of China (Grant No. 2021YFA1401200)the National Natural Science Foundation of China (Grant Nos. 61971437, 92050117, and U21A20140)+2 种基金the Beijing Outstanding Young Scientist Program (Grant No.BJJWZYJH01201910007022)the Natural Science Foundation of Shaanxi Province (Grant Nos. 2020JM-342, and 2022JM-352)the Beijing Institute of Technology Research Fund Program for Young Scholars (Grant No. XSQD-201904005)。
文摘Chirality, as one of the ubiquitous properties in nature, has aroused striking attention in the fields of physics and materials sciences. For tailoring of light with more degree of freedom, circular dichroism has been considered as the auxiliary dimension to improving such an issue. Inspired by the Born-Kuhn plasmonic oscillation model, we demonstrate and discuss a chiral resonator to reveal reverse circular dichroism within two separate frequency bands in the microwave regime. The underlying physical mechanisms of bonding and anti-bounding modes are analyzed via transmission/reflection spectra and surface current distributions for different chiral enantiomers. To leverage the proposed paradigm to the application levels, especially for metaholography, we conduct the numerical simulation and experimental demonstration of two proofs of principles. Based on the Pancharatnam-Berry phase/amplitude modulation and complex-amplitude manipulation, respectively, the meta-holograms with independent targets of reconstructing images in full-space and reflected regions are achieved. Significantly, our paradigm may promise further applications in spin-controlled meta-devices for image processing, information encryption, anti-counterfeiting,remote sensing, and radar systems.
基金This work was supported by the National Key R&D Projects of China(Grant Nos.2019YFA0308602 and 2016YFA0300402)the National Natural Science Foundation of China(Grant No.11774305)the Fundamental Research Funds for the Central Universities of China.
文摘We investigated the coexistence of superconductivity and antiferromagnetic order in the compound Er_(2)O_(2)Bi with anti-ThCr_(2)Si_(2)-type structure through resistivity,magnetization,specific heat measurements and first-principle calculations.The superconducting transition temperature Tc of 1.23 K and antiferromagnetic transition temperature TN of 3 K are observed in the sample with the best nominal composition.The superconducting upper critical field H_(c2)(0)and electron-phonon coupling constantλe−ph in Er_(2)O_(2)Bi are similar to those in the previously reported non-magnetic superconductor Y_(2)O_(2)Bi with the same structure,indicating that the superconductivity in Er_(2)O_(2)Bi may have the same origin as in Y_(2)O_(2)Bi.The first-principle calculations of Er_(2)O_(2)Bi show that the Fermi surface is mainly composed of the Bi 6p orbitals both in the paramagnetic and antiferromagnetic state,implying minor effect of the 4f electrons on the Fermi surface.Besides,upon increasing the oxygen incorporation in Er_(2)O_(x)Bi,Tc increases from 1 to 1.23 K and TN decreases slightly from 3 K to 2.96 K,revealing that superconductivity and antiferromagnetic order may compete with each other.The Hall effect measurements indicate that hole-type carrier density indeed increases with increasing oxygen content,which may account for the variations of Tc and TN with different oxygen content.
基金This work was supported by the National Natural Science Foundation of China Grants(No.81773215,82173074)CAMS Innovation Fund for Medical Sciences(CIFMS)(No.2021-I2M-1-002).
文摘The significance of exosomes has emerged in a variety of physiological processes and diseases.Pancreatic cancer remains one of the most lethal diseases at present.Recently,increasing evidence has suggested that exosomes are vital for mediating the elaborate interaction of highly heterogeneous cell clusters within the pancreatic tumor microenvironment,contributing to activating pancreatic stellate cells and cancer-associated fibroblasts,compromising immune cells,and enhancing angiogenesis.Besides their natural and intrinsic roles,exosomes may provide a novel potential way for pancreatic cancer management and therapy as well.Thus,exosomes not only mediate cellular communication during pancreatic cancer progression but also serve as a promising player in precise pancreatic cancer management and treatment.To comprehensively summarize the role of exosomes in pancreatic cancer,we searched the PubMed database and reviewed all relevant original studies.
基金Project supported by the National Natural Science Foundation of China(No.61331006)
文摘An improved large signal model for InP HEMTs is proposed in this paper.The channel current and charge model equations are constructed based on the Angelov model equations.Both the equations for channel current and gate charge models were all continuous and high order drivable,and the proposed gate charge model satisfied the charge conservation.For the strong leakage induced barrier reduction effect of InP HEMTs,the Angelov current model equations are improved.The channel current model could fit DC performance of devices.A 2×25μm×70 nm InP HEMT device is used to demonstrate the extraction and validation of the model,in which the model has predicted the DC I–V,C–V and bias related S parameters accurately.
