For a graph G,a vertex is said to be pendant if its neighborhood contains exactly one vertex.In this paper,we determine the extremal graphs among all n-vertex graphs with the minimum spectral radius andβpendant verti...For a graph G,a vertex is said to be pendant if its neighborhood contains exactly one vertex.In this paper,we determine the extremal graphs among all n-vertex graphs with the minimum spectral radius andβpendant vertices,whereβe{1,2,3,4,n-3,n-2,n-1}.展开更多
Polymer acceptor configuration and aggregation behavior are critical in determining the photovoltaic performance of all-polymer solar cells(all-PSCs).Effectively manipulating polymer self-aggregation through structura...Polymer acceptor configuration and aggregation behavior are critical in determining the photovoltaic performance of all-polymer solar cells(all-PSCs).Effectively manipulating polymer self-aggregation through structural design to optimize the blend morphology remains challenging.Herein,we present a simple yet effective design strategy to modulate the aggregation behavior of the Y-series-based polymer acceptor PY-V-γby introducing a pendant-fluorinated Y-series acceptor(Y2F-ET)into the main-conjugated backbone.Two random copolymer acceptors(PY-EY-5 and PY-EY-20)were synthesized with varying molar fractions of Y2F-ET pendant monomers.Our findings revealed that both the solution-phase and solid-state aggregation behaviors were progressively suppressed as the Y2F-ET content increased.Compared to the highly self-aggregating PY-V-γ-based all-PSCs,the more amorphous PY-EY-5 enabled devices to achieve an increased device efficiency from 17.31%to 18.45%,which is attributed to the slightly smaller polymer phase-separation domain sizes and reduced molecular aggregation in the PM6:PY-EY-5 blend.Moreover,the finely tuned blend morphology exhibited superior thermal stability,underscoring the significant advantages of the Y-series pendant random copolymerization approach.展开更多
The interest in curtailing environmental pollution issues through physical separation processes has inspired an extensive search for novel nanoporous materials with exceptional adsorption capabilities.Covalent triazin...The interest in curtailing environmental pollution issues through physical separation processes has inspired an extensive search for novel nanoporous materials with exceptional adsorption capabilities.Covalent triazine frameworks(CTFs),emerged as a class of crystalline covalent organic frameworks(COFs),have been widely examined for various separation applications,owing to their large porosity,high stability,and rich nitrogen(N)doping.The development of CTFs for efficient adsorption of mercury(Ⅱ)(Hg^(2+))is of great importance for the field,whereas it is rarely attempted,on account of limited synthetic strategies and unknown structural-property relations of conventional CTFs derived from ionothermal approaches.Herein,we report rational synthesis of a crystalline CTF with methylthio pendant arms for efficient removal of Hg^(2+)with an exceptional capacity of 751 mg·g^(-1),ranking at the top among previously-reported adsorbents.This work may open up new possibility in the synthesis of COFs for various separations.展开更多
Electron beam–directed energy deposition(EB–DED)has emerged as a promising wire-based metal additive manufacturing technique.However,the effects of EBs on pendant droplets at wire tips have not yet been determined.T...Electron beam–directed energy deposition(EB–DED)has emerged as a promising wire-based metal additive manufacturing technique.However,the effects of EBs on pendant droplets at wire tips have not yet been determined.The aim of this study is to enhance the understanding of this action by analyzing the mechanism of droplet oscillation.The pendant droplet oscillation phenomenon hinders the stable transfer of droplets to the molten pool and limits the feasibility of manufacturing complex lattice structures by EB–DED.Hence,another aim of this study is to create an oscillation suppression method.An escalating asymmetric amplitude is the main characteristic of droplet oscillation.The primary oscillationinducing force is the recoil force generated from the EB-acted local surface of the droplet.The physical mechanism of this force is the rapid increase and uneven distribution of the local surface temperature caused by the partial action of the EB.The prerequisites for droplet oscillation include vacuum conditions,high power densities,and bypass wire feeding processes.The proposed EB–dynamic surrounding melting(DSM)method can be applied to conveniently and effectively suppress oscillations,enable the accurate transfer of droplets to the molten pool,and achieve stable processes for preparing the strut elements of lattice structures.Lowering the temperature and improving the uniformity of its distribution are the mechanisms of oscillation suppression in EB–DSM.In this study,the physical basis for interpreting the mechanism by which EBs act on droplets and the technical basis for using EB–DED to prepare complex lattice structure parts are provided.展开更多
As part of a better understanding of drying liquids within porous materials, measurements from 293 to 343 K of deionized water surface tension in air as a function of relative humidity are exposed. Experimental work w...As part of a better understanding of drying liquids within porous materials, measurements from 293 to 343 K of deionized water surface tension in air as a function of relative humidity are exposed. Experimental work was carried out using the pendant drop method coupled with image analysis within an adapted instrumented climatic chamber. Results show that surface tension linearly decreases when relative humidity increases. Although the effect of humidity is less compared to that of the temperature and even less compared to a surfactant impact, it must not be neglected and values have to be mentioned when dealing with water evaporation. Modifying surface tension also affects the pendant drop shape. The drying kinetics of the pendant drop volume and its outer shell are connected to this change of shape. Steam in the air can be assimilated to a wetting agent, hence a surfactant, and can be used in an environmental-friendly way to ease the drying stage. Indeed, the challenge is to limit the risk of cracking and damaging pieces during this crucial step in material processing.展开更多
In order to further improve the serial ports communication mode of the general Flex Pendant for industrial robot,a multiple serial communication mode is put forward. It is used to meet the stability of data transmissi...In order to further improve the serial ports communication mode of the general Flex Pendant for industrial robot,a multiple serial communication mode is put forward. It is used to meet the stability of data transmission,transmission distance,transmission speed,anti-interference and cost-effective. Using ADUM1201 single direction dual channel digital isolator,two pieces of MAX13487 E and a piece of MAX3232 chip to transmit data and files, and to control chip’ s electrical level. Selecting the RS232, RS422 and RS485 communication mode,the serial ports of the general Flex Pendant of industrial robot is optimized.展开更多
The fluorescence behaviours of a new polymer poly [oxy-2 (4-N, N-dimethylaminobenzyl) propane-1 , 3-diyloxy-terephthaloyl] (Ⅰ) in solution were studied. Inter-and intra -molecular exciplex is formed between the singl...The fluorescence behaviours of a new polymer poly [oxy-2 (4-N, N-dimethylaminobenzyl) propane-1 , 3-diyloxy-terephthaloyl] (Ⅰ) in solution were studied. Inter-and intra -molecular exciplex is formed between the singlet excited state of N, N- dimethylanilino group (abbreviated to DMA) and the ground state of terephthalate group (abbreviated to TP). The intensity ratio of the long wavelength exciplex fluorescence to the short wavelength emission of DMA group is used as an index for the inter-and intra-molecular interaction of chromophores. The results are compared with model polymer polyoxy-2-(4-N ,N-dimethylaminobenzyl) propanc-1 , 3-diyloxyadipoyl (Ⅱ), model monomer compound 4-N, N-dimethylaminobenzylmethyl terephthalate(Ⅲ) and diethyl 2-( 4-N, N-dimethylaminobenzyl) malonate (Ⅳ). Polymer association derived by electron donor and acceptor interaction (EDA) is further verified as a key role in the interpolymer exciplex formation . The fluorescence decay time of (Ⅰ) and monomer (Ⅲ) are measured in solutions.展开更多
Two new dioxo tetraamine ligands L1 and L2 have been synthesized and characterized by 1H NMR, IR, MS and elemental analysis,Their protonation eonstants and complex formation constants with Cu2+have been determined by ...Two new dioxo tetraamine ligands L1 and L2 have been synthesized and characterized by 1H NMR, IR, MS and elemental analysis,Their protonation eonstants and complex formation constants with Cu2+have been determined by potentiometric titration, The X-ray crystal structure of L1 has been determined.展开更多
In this paper, we determine the unique graph with the largest signless Laplacian spectral radius among all the tricyclic graphs with n vertices and k pendant vertices.
Started with 100 workers and staff, the Guangdong based Huabao Electrical Appliances Factory has now made 500 products in 50 categories. It boasts 2,000 staff and fixed assets worth RMB80 million. In 1988, the factory...Started with 100 workers and staff, the Guangdong based Huabao Electrical Appliances Factory has now made 500 products in 50 categories. It boasts 2,000 staff and fixed assets worth RMB80 million. In 1988, the factory was cited as an advanced enterprise in earning foreign exchange among light industries nationwide, by the Ministry of Light Industry; and Huabao electrical appliances were named high quality products in an appraisal sponsored by the Ministry of Light Industry.展开更多
Maltose-pendant polymer/mica nanocomposites were prepared by a solution intercalation method. For organic composite part, 1) maltose-pendant polymer (homopolymer) and 2) the copolymer of maltose-pendant monomer and a ...Maltose-pendant polymer/mica nanocomposites were prepared by a solution intercalation method. For organic composite part, 1) maltose-pendant polymer (homopolymer) and 2) the copolymer of maltose-pendant monomer and a small amount of N,N-Dimethylamino propylacrylamide, methyl chloride quartenary were used. The morphological studies (XRD and FE-SEM) revealed that the hybrid of maltose-pendant polymer was a conventional phase separated composite. On the other hand, the hybrid using the copolymer exhibited exfoliated structure. Both the conventional composite of maltose-pendant polymer and the nanocomposite of copolymer were applied to a coating material for oxygen gas barrier layer on a nylon-6 film, and oxygen transmission rates of the films were evaluated. Maltose-pendant polymer had a good oxygen barrier property under dry condition, and the barrier property under wet condition was improved by the hybridization with mica. In contrast, the barrier property of copolymer was slightly inferior to that of maltosependant polymer. However, under dry condition, it can be seen that the nanocomposite of copolymer improves the barrier property more effectively than the case of conventional composite of maltose-pendant polymer.展开更多
Background:Reviewing historical evidence in the various schools of traditional medicine shows that numerous methods have been used to maintain human good health and treatment of diseases.Persian medicine(PM)scholars h...Background:Reviewing historical evidence in the various schools of traditional medicine shows that numerous methods have been used to maintain human good health and treatment of diseases.Persian medicine(PM)scholars have been employed different methods to prescribe medications,which can be classified into two main groups:internal uses,including oral,parenteral,and anal,and also external uses such as topical,transdermal,and applying pendants.In this study,we aim to introduce some of the therapeutic pendants.Methods:We reviewed the most famous PM textbooks and current evidence in relevant databases such as PubMed,Science Direct,Scopus,Google scholar and SID related to the topic.Results:In this study,about 100 traditional therapeutic substances were found and finally,thirty-two of them were represented.They were often stones,and some of them were other materials such as metals,gums,and herbs.According to the PM,the utilization of pendants,in addition to cosmetic purposes,has been considered to maintain the health and treatment of some diseases.Therapeutic pendants can be considered as a kind of external medication use in which therapeutic materials are hung on the body surface.The external use of pendants could have curative effects with their close contact to the body surface.Conclusion:Pendant therapy may probably be considered as a non-invasive and easy-to-use treatment with unnoticeable side effects that can be utilized along with other therapies.展开更多
A series of new macrocyclic dioxo 13 aneN 4 bearing various functional pendants, 2 methylfuran (LF), 2 methylthiophene (LT), 2 methylpyridine (LP), have been synthesized and characterized, where dioxo 13 aneN ...A series of new macrocyclic dioxo 13 aneN 4 bearing various functional pendants, 2 methylfuran (LF), 2 methylthiophene (LT), 2 methylpyridine (LP), have been synthesized and characterized, where dioxo 13 aneN 4 is 1,4,7,10 tetraazacyclotridecane 11,13 dione. The solution behaviours of the nickel(Ⅱ) complexes have been studied by Uv vis, cyclic voltammetric techniques. The red shifts were observed for the absorption band maxima of the electronic spectra from NiLR 1 to NiLR 2 (R=2 methylfuran, 2 methylthiophene, 2 methylpyridine). The value of E 1/2 of the NiLR 2 is less than NiLR 1 and both of them are lower than that of the nickel(Ⅱ) complex of the unsubstituted ligand, and these reasons are discussed.展开更多
This paper examines how polymer-coated nanoparticles(PNPs)affect interfacial tension(IFT)and their possible use in oil recovery(EOR).In particular,the paper investigates how the IFT between brine and dead oil can be l...This paper examines how polymer-coated nanoparticles(PNPs)affect interfacial tension(IFT)and their possible use in oil recovery(EOR).In particular,the paper investigates how the IFT between brine and dead oil can be lowered with the help of PNPs prepared with Arabic gum and silica nanoparticles at different temperatures and salinity.IFT was measured at pressures of 25 to 1900 psi and temperatures varying between 25℃and 55℃using the pendant drop technique.They demonstrate a continuous decline of IFT with temperature(the highest observed one is at 55℃).Furthermore,elevated salinity(NaCl)resulted in reduced IFT,but it resulted more at high concentrations.High IFT further was reduced by the presence of silica nanoparticles and Arabic gum with the largest IFT reduction of about 46%potentially occurring in the brine-oil system with nanoparticles.These results indicate that PNPs may provide an attractive solution to enhancing EOR due to their ability to lower IFT,improve the efficiency of oil displacement transport in more difficult reservoirs.The research prepares the ground of additional studies regarding the use of nanotechnology in EOR processes.展开更多
Natural surfactants that are present in complex crude oil may induce spontaneous emulsification in the oil and brine phases that co-exist in rock pores.This process is known to be affected by the salinity of brine.How...Natural surfactants that are present in complex crude oil may induce spontaneous emulsification in the oil and brine phases that co-exist in rock pores.This process is known to be affected by the salinity of brine.However,the role of salinity in water-oil micro-emulsification is not fully understood.In this paper,we report on our experimental studies of the effect of salinity on spontaneous emulsification in a“mixture”of dodecane and brine.The dodecane contains SPAN 80 surfactant and brine with different salinity values,varying from 0.2%to 20%(by weight).For our observations,we use dynamic light scattering(DLS)technique to capture nano-scale emulsion formation and pendant drop method to observe micro-scale emulsion dynamics.The DLS experiments show that small(2.2 nm)and medium-sized emulsions(100 nm)are formed at low salinities,while at higher salinities only smaller droplets are formed and emulsification is reduced.In pendant drop experiments,dodecane and heptane systems were tested over 13 h.Heptane exhibited faster emulsification at water-oil interfaces in the cases with pure water and low salinity brine(0.2%),where the changes at interfacial area occurring within two hours and significant droplet shrinkage by 13 h.Lower salinity enhances micelle activity and emulsification,while higher salinities(2%,5%,and 20%)stabilize the oil-water interface and suppress emulsion formation.Dodecane exhibits a similar trend in emulsification but forms more stable emulsions and maintains a more stable water-oil interface compared to heptane.Additionally,we present the theory of reverse micelle exclusion through a theoretical derivation,providing a deeper understanding of the emulsification mechanism.Four distinct scenarios are schematically presented to explain the influence of salinity on spontaneous emulsification,illustrating how varying salinity levels affect micelle formation and emulsion behaviour.This study provides valuable insights into optimizing salinity levels in enhanced oil recovery.展开更多
合成润滑油广泛应用于各类制冷与热泵设备,其热物理性质是分析热力学能效、换热性能和沿程压降的基础数据,对评价和优化系统结构具有重要意义。本文研制了一套低温、高压悬滴法表面张力实验测量系统,并使用振动管密度计与悬滴法表面张...合成润滑油广泛应用于各类制冷与热泵设备,其热物理性质是分析热力学能效、换热性能和沿程压降的基础数据,对评价和优化系统结构具有重要意义。本文研制了一套低温、高压悬滴法表面张力实验测量系统,并使用振动管密度计与悬滴法表面张力实验系统开展了基础润滑油(POE、PVE和PAG)的液相密度和表面张力实验研究,测量的温度范围为243.15~363.15 K,液相密度和表面张力测量的扩展不确定度分别在0.2%和0.1 m N·m^(-1)以内。实验结果表明:基础润滑油的液相密度和表面张力均随温度的增大而减小,关联方程的计算值与实验值的绝对平均偏差分别小于0.04%和0.5%。展开更多
文摘For a graph G,a vertex is said to be pendant if its neighborhood contains exactly one vertex.In this paper,we determine the extremal graphs among all n-vertex graphs with the minimum spectral radius andβpendant vertices,whereβe{1,2,3,4,n-3,n-2,n-1}.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.22279094 and 22409149)Hubei Provincial Natural Science Foundation(No.2024 AFB068)Fundamental Research Funds for the Central Universities。
文摘Polymer acceptor configuration and aggregation behavior are critical in determining the photovoltaic performance of all-polymer solar cells(all-PSCs).Effectively manipulating polymer self-aggregation through structural design to optimize the blend morphology remains challenging.Herein,we present a simple yet effective design strategy to modulate the aggregation behavior of the Y-series-based polymer acceptor PY-V-γby introducing a pendant-fluorinated Y-series acceptor(Y2F-ET)into the main-conjugated backbone.Two random copolymer acceptors(PY-EY-5 and PY-EY-20)were synthesized with varying molar fractions of Y2F-ET pendant monomers.Our findings revealed that both the solution-phase and solid-state aggregation behaviors were progressively suppressed as the Y2F-ET content increased.Compared to the highly self-aggregating PY-V-γ-based all-PSCs,the more amorphous PY-EY-5 enabled devices to achieve an increased device efficiency from 17.31%to 18.45%,which is attributed to the slightly smaller polymer phase-separation domain sizes and reduced molecular aggregation in the PM6:PY-EY-5 blend.Moreover,the finely tuned blend morphology exhibited superior thermal stability,underscoring the significant advantages of the Y-series pendant random copolymerization approach.
基金The National Natural Science Foundation of China(22078349,22005319,52170109)Self-deployment Program from Lanzhou Institute of Chemical Physics(E30159SQ).
文摘The interest in curtailing environmental pollution issues through physical separation processes has inspired an extensive search for novel nanoporous materials with exceptional adsorption capabilities.Covalent triazine frameworks(CTFs),emerged as a class of crystalline covalent organic frameworks(COFs),have been widely examined for various separation applications,owing to their large porosity,high stability,and rich nitrogen(N)doping.The development of CTFs for efficient adsorption of mercury(Ⅱ)(Hg^(2+))is of great importance for the field,whereas it is rarely attempted,on account of limited synthetic strategies and unknown structural-property relations of conventional CTFs derived from ionothermal approaches.Herein,we report rational synthesis of a crystalline CTF with methylthio pendant arms for efficient removal of Hg^(2+)with an exceptional capacity of 751 mg·g^(-1),ranking at the top among previously-reported adsorbents.This work may open up new possibility in the synthesis of COFs for various separations.
基金supported by the National Natural Science Foundation of China(52375349)the Beijing Municipal Natural Science Foundation(3222008).
文摘Electron beam–directed energy deposition(EB–DED)has emerged as a promising wire-based metal additive manufacturing technique.However,the effects of EBs on pendant droplets at wire tips have not yet been determined.The aim of this study is to enhance the understanding of this action by analyzing the mechanism of droplet oscillation.The pendant droplet oscillation phenomenon hinders the stable transfer of droplets to the molten pool and limits the feasibility of manufacturing complex lattice structures by EB–DED.Hence,another aim of this study is to create an oscillation suppression method.An escalating asymmetric amplitude is the main characteristic of droplet oscillation.The primary oscillationinducing force is the recoil force generated from the EB-acted local surface of the droplet.The physical mechanism of this force is the rapid increase and uneven distribution of the local surface temperature caused by the partial action of the EB.The prerequisites for droplet oscillation include vacuum conditions,high power densities,and bypass wire feeding processes.The proposed EB–dynamic surrounding melting(DSM)method can be applied to conveniently and effectively suppress oscillations,enable the accurate transfer of droplets to the molten pool,and achieve stable processes for preparing the strut elements of lattice structures.Lowering the temperature and improving the uniformity of its distribution are the mechanisms of oscillation suppression in EB–DSM.In this study,the physical basis for interpreting the mechanism by which EBs act on droplets and the technical basis for using EB–DED to prepare complex lattice structure parts are provided.
文摘As part of a better understanding of drying liquids within porous materials, measurements from 293 to 343 K of deionized water surface tension in air as a function of relative humidity are exposed. Experimental work was carried out using the pendant drop method coupled with image analysis within an adapted instrumented climatic chamber. Results show that surface tension linearly decreases when relative humidity increases. Although the effect of humidity is less compared to that of the temperature and even less compared to a surfactant impact, it must not be neglected and values have to be mentioned when dealing with water evaporation. Modifying surface tension also affects the pendant drop shape. The drying kinetics of the pendant drop volume and its outer shell are connected to this change of shape. Steam in the air can be assimilated to a wetting agent, hence a surfactant, and can be used in an environmental-friendly way to ease the drying stage. Indeed, the challenge is to limit the risk of cracking and damaging pieces during this crucial step in material processing.
基金supported by the National Key Technology R&D Program(2015BAK06B04)the key technologies R&D Program of Tianjin(14ZCZDSF00022)
文摘In order to further improve the serial ports communication mode of the general Flex Pendant for industrial robot,a multiple serial communication mode is put forward. It is used to meet the stability of data transmission,transmission distance,transmission speed,anti-interference and cost-effective. Using ADUM1201 single direction dual channel digital isolator,two pieces of MAX13487 E and a piece of MAX3232 chip to transmit data and files, and to control chip’ s electrical level. Selecting the RS232, RS422 and RS485 communication mode,the serial ports of the general Flex Pendant of industrial robot is optimized.
文摘The fluorescence behaviours of a new polymer poly [oxy-2 (4-N, N-dimethylaminobenzyl) propane-1 , 3-diyloxy-terephthaloyl] (Ⅰ) in solution were studied. Inter-and intra -molecular exciplex is formed between the singlet excited state of N, N- dimethylanilino group (abbreviated to DMA) and the ground state of terephthalate group (abbreviated to TP). The intensity ratio of the long wavelength exciplex fluorescence to the short wavelength emission of DMA group is used as an index for the inter-and intra-molecular interaction of chromophores. The results are compared with model polymer polyoxy-2-(4-N ,N-dimethylaminobenzyl) propanc-1 , 3-diyloxyadipoyl (Ⅱ), model monomer compound 4-N, N-dimethylaminobenzylmethyl terephthalate(Ⅲ) and diethyl 2-( 4-N, N-dimethylaminobenzyl) malonate (Ⅳ). Polymer association derived by electron donor and acceptor interaction (EDA) is further verified as a key role in the interpolymer exciplex formation . The fluorescence decay time of (Ⅰ) and monomer (Ⅲ) are measured in solutions.
文摘Two new dioxo tetraamine ligands L1 and L2 have been synthesized and characterized by 1H NMR, IR, MS and elemental analysis,Their protonation eonstants and complex formation constants with Cu2+have been determined by potentiometric titration, The X-ray crystal structure of L1 has been determined.
基金Supported by the National Natural Science Foundation of China(Grant Nos.1087120461170311)the Fundamental Research Funds for the Central Universities(Grant No.09CX04003A)
文摘In this paper, we determine the unique graph with the largest signless Laplacian spectral radius among all the tricyclic graphs with n vertices and k pendant vertices.
文摘Started with 100 workers and staff, the Guangdong based Huabao Electrical Appliances Factory has now made 500 products in 50 categories. It boasts 2,000 staff and fixed assets worth RMB80 million. In 1988, the factory was cited as an advanced enterprise in earning foreign exchange among light industries nationwide, by the Ministry of Light Industry; and Huabao electrical appliances were named high quality products in an appraisal sponsored by the Ministry of Light Industry.
文摘Maltose-pendant polymer/mica nanocomposites were prepared by a solution intercalation method. For organic composite part, 1) maltose-pendant polymer (homopolymer) and 2) the copolymer of maltose-pendant monomer and a small amount of N,N-Dimethylamino propylacrylamide, methyl chloride quartenary were used. The morphological studies (XRD and FE-SEM) revealed that the hybrid of maltose-pendant polymer was a conventional phase separated composite. On the other hand, the hybrid using the copolymer exhibited exfoliated structure. Both the conventional composite of maltose-pendant polymer and the nanocomposite of copolymer were applied to a coating material for oxygen gas barrier layer on a nylon-6 film, and oxygen transmission rates of the films were evaluated. Maltose-pendant polymer had a good oxygen barrier property under dry condition, and the barrier property under wet condition was improved by the hybridization with mica. In contrast, the barrier property of copolymer was slightly inferior to that of maltosependant polymer. However, under dry condition, it can be seen that the nanocomposite of copolymer improves the barrier property more effectively than the case of conventional composite of maltose-pendant polymer.
文摘Background:Reviewing historical evidence in the various schools of traditional medicine shows that numerous methods have been used to maintain human good health and treatment of diseases.Persian medicine(PM)scholars have been employed different methods to prescribe medications,which can be classified into two main groups:internal uses,including oral,parenteral,and anal,and also external uses such as topical,transdermal,and applying pendants.In this study,we aim to introduce some of the therapeutic pendants.Methods:We reviewed the most famous PM textbooks and current evidence in relevant databases such as PubMed,Science Direct,Scopus,Google scholar and SID related to the topic.Results:In this study,about 100 traditional therapeutic substances were found and finally,thirty-two of them were represented.They were often stones,and some of them were other materials such as metals,gums,and herbs.According to the PM,the utilization of pendants,in addition to cosmetic purposes,has been considered to maintain the health and treatment of some diseases.Therapeutic pendants can be considered as a kind of external medication use in which therapeutic materials are hung on the body surface.The external use of pendants could have curative effects with their close contact to the body surface.Conclusion:Pendant therapy may probably be considered as a non-invasive and easy-to-use treatment with unnoticeable side effects that can be utilized along with other therapies.
文摘A series of new macrocyclic dioxo 13 aneN 4 bearing various functional pendants, 2 methylfuran (LF), 2 methylthiophene (LT), 2 methylpyridine (LP), have been synthesized and characterized, where dioxo 13 aneN 4 is 1,4,7,10 tetraazacyclotridecane 11,13 dione. The solution behaviours of the nickel(Ⅱ) complexes have been studied by Uv vis, cyclic voltammetric techniques. The red shifts were observed for the absorption band maxima of the electronic spectra from NiLR 1 to NiLR 2 (R=2 methylfuran, 2 methylthiophene, 2 methylpyridine). The value of E 1/2 of the NiLR 2 is less than NiLR 1 and both of them are lower than that of the nickel(Ⅱ) complex of the unsubstituted ligand, and these reasons are discussed.
文摘This paper examines how polymer-coated nanoparticles(PNPs)affect interfacial tension(IFT)and their possible use in oil recovery(EOR).In particular,the paper investigates how the IFT between brine and dead oil can be lowered with the help of PNPs prepared with Arabic gum and silica nanoparticles at different temperatures and salinity.IFT was measured at pressures of 25 to 1900 psi and temperatures varying between 25℃and 55℃using the pendant drop technique.They demonstrate a continuous decline of IFT with temperature(the highest observed one is at 55℃).Furthermore,elevated salinity(NaCl)resulted in reduced IFT,but it resulted more at high concentrations.High IFT further was reduced by the presence of silica nanoparticles and Arabic gum with the largest IFT reduction of about 46%potentially occurring in the brine-oil system with nanoparticles.These results indicate that PNPs may provide an attractive solution to enhancing EOR due to their ability to lower IFT,improve the efficiency of oil displacement transport in more difficult reservoirs.The research prepares the ground of additional studies regarding the use of nanotechnology in EOR processes.
基金the funding from National Natural Science Foundation of China(Grant No.52474105).
文摘Natural surfactants that are present in complex crude oil may induce spontaneous emulsification in the oil and brine phases that co-exist in rock pores.This process is known to be affected by the salinity of brine.However,the role of salinity in water-oil micro-emulsification is not fully understood.In this paper,we report on our experimental studies of the effect of salinity on spontaneous emulsification in a“mixture”of dodecane and brine.The dodecane contains SPAN 80 surfactant and brine with different salinity values,varying from 0.2%to 20%(by weight).For our observations,we use dynamic light scattering(DLS)technique to capture nano-scale emulsion formation and pendant drop method to observe micro-scale emulsion dynamics.The DLS experiments show that small(2.2 nm)and medium-sized emulsions(100 nm)are formed at low salinities,while at higher salinities only smaller droplets are formed and emulsification is reduced.In pendant drop experiments,dodecane and heptane systems were tested over 13 h.Heptane exhibited faster emulsification at water-oil interfaces in the cases with pure water and low salinity brine(0.2%),where the changes at interfacial area occurring within two hours and significant droplet shrinkage by 13 h.Lower salinity enhances micelle activity and emulsification,while higher salinities(2%,5%,and 20%)stabilize the oil-water interface and suppress emulsion formation.Dodecane exhibits a similar trend in emulsification but forms more stable emulsions and maintains a more stable water-oil interface compared to heptane.Additionally,we present the theory of reverse micelle exclusion through a theoretical derivation,providing a deeper understanding of the emulsification mechanism.Four distinct scenarios are schematically presented to explain the influence of salinity on spontaneous emulsification,illustrating how varying salinity levels affect micelle formation and emulsion behaviour.This study provides valuable insights into optimizing salinity levels in enhanced oil recovery.
文摘合成润滑油广泛应用于各类制冷与热泵设备,其热物理性质是分析热力学能效、换热性能和沿程压降的基础数据,对评价和优化系统结构具有重要意义。本文研制了一套低温、高压悬滴法表面张力实验测量系统,并使用振动管密度计与悬滴法表面张力实验系统开展了基础润滑油(POE、PVE和PAG)的液相密度和表面张力实验研究,测量的温度范围为243.15~363.15 K,液相密度和表面张力测量的扩展不确定度分别在0.2%和0.1 m N·m^(-1)以内。实验结果表明:基础润滑油的液相密度和表面张力均随温度的增大而减小,关联方程的计算值与实验值的绝对平均偏差分别小于0.04%和0.5%。
