One of the most challenging factors affecting impression quality and good marginal fit is the gingival retraction method, which aims to separate the gingiva from the tooth to expose the finishing line of the prepared ...One of the most challenging factors affecting impression quality and good marginal fit is the gingival retraction method, which aims to separate the gingiva from the tooth to expose the finishing line of the prepared tooth. Bleeding and contamination from the crevicular fluid may compete for space with the impression material within the sulcus, leading to indistinct preparations and a lack of detail at the margin. In addition, such procedures might damage the PDL and cause permanent recession. Flowable composite cable, as opposed to traditional retraction cords, offers the proper marginal seal and visibility during the impression record because of its lower viscosity, improved adaptability, and elastic properties. The aim of this report is to present a brand-new, innovative method for controlling gingival hemorrhage in addition to the gingival retraction in restorative and prosthodontic treatment by utilizing a flowable composite during the final impression record procedure. In these case reports, the flowable composite cord technique is used instead of traditional gingival cords to modify and refine the gingival tissue before taking the traditional final impression or digital scan. Two cases were done for patients undergoing fixed prosthodontics and veneer treatment within a 2-year follow-up period. In addition, the flowable composite cord was used as temporary restoration before the final prosthetic cementation or under the provisional crowns. As a result, clean and healthy gingival tissues render cementation of the final prosthesis quicker and easier to perform. The patients in both cases claimed that their prosthodontic treatments, which involved the application of a flowable composite cord to temporarily retraction the gingiva, had produced good outcomes at the yearlong follow-up. In conclusion, the flowable composite cord technique is found to be a useful tool to improve the quality of impressions in fixed prosthodontics by providing excellent access for impression material to record fine details of the finish line of the prepared tooth structure, and to alter the inflamed tissue into a healthy tissue.展开更多
A dry flowable formulation of Clonostachys rosea with fungicidal activity against Sclerotinia sclerotiorum was prepared by spray drying. The formulation was optimized by a four-factor, three-level orthogonal experimen...A dry flowable formulation of Clonostachys rosea with fungicidal activity against Sclerotinia sclerotiorum was prepared by spray drying. The formulation was optimized by a four-factor, three-level orthogonal experiment to screen inert ingredients and spray-drying conditions. The optimal dry flowable formulation of C. rosea included 30% C. rosea （ratio of conidia powder and its fermentation broth is 1：3）, 3% Morwet EFW, 4% K12, 10% Morwet D425, 9% sodium salt of polynaphthalene sulphonic acid （NNO）, 5% croscarmellose sodium, 5% （NH4）2SO4, 0.5% carboxymethyl cellulose sodium （CMC-Na）, 1% oxalic acid and palygorskite （carrier） up to 100%. The formulation exhibited good physical characteristics, such as high dispersibility, viability and a long shelf life. Plate antagonism tests and pot trials indicated that the dry flowable formulation was very effective against S. sclerotiorum, with control efficiency of up to 88.30%. This dry flowable formulation of C. rosea is a new potential commercial fungicide for spray drying to control S. sclerotiorum.展开更多
为满足高校办公信息化的个性化需求,缩短流程业务办理时间,针对传统操作方式任务繁重、效率低下的现状,介绍了业务流程建模注解BPMN(Business Process Modeling Notation),提出通过Flowable工作流引擎实现业务流程中的逻辑处理。通过请...为满足高校办公信息化的个性化需求,缩短流程业务办理时间,针对传统操作方式任务繁重、效率低下的现状,介绍了业务流程建模注解BPMN(Business Process Modeling Notation),提出通过Flowable工作流引擎实现业务流程中的逻辑处理。通过请假申请流程对工作流的定义过程进行了分析,基于Flowable设计并实现了高校办公系统,使用表明能够满足高校办公需求。展开更多
This research investigated the use of wood ash to partially replace cement or sand in conventional concrete, roller compacted concrete (RCC), and flowable fill. The main focus was to determine how the wood ash additio...This research investigated the use of wood ash to partially replace cement or sand in conventional concrete, roller compacted concrete (RCC), and flowable fill. The main focus was to determine how the wood ash addition affected the main fresh and hardened properties of these materials. It was found that the wood ash could be successfully incorporated into the conventional concrete. In particular, the wood ash addition not only accelerated the setting, but also improved the early and the 28-day compressive strength of concrete that contained the blast furnace slag. It was also observed that the wood ash could be positively added into RCC to facilitate the compaction and reduce the risk of segregation. In addition, the wood ash can be beneficially introduced into the flowable fill mixtures to facilitate flow, to alleviate bleeding and subsidence, as well as to achieve controlled strength especially when combined with the class C or the class F fly ash.展开更多
目的:比较Fuji IX GP玻璃离子水门汀、3M ESPE Filtek^(TM) Bulk Fill Flowable树脂、VOCO Polofil Supra树脂及Beautiful Flow Plus F03树脂修复根面龋的临床疗效。方法:选取后牙根面龋患者128例(422颗患牙),按照充填修复材料分为A组(F...目的:比较Fuji IX GP玻璃离子水门汀、3M ESPE Filtek^(TM) Bulk Fill Flowable树脂、VOCO Polofil Supra树脂及Beautiful Flow Plus F03树脂修复根面龋的临床疗效。方法:选取后牙根面龋患者128例(422颗患牙),按照充填修复材料分为A组(Fuji IX GP玻璃离子水门汀修复)34例、B组(3M ESPE Filtek^(TM) Bulk Fill Flowable树脂修复)29例、C组(VOCO Polofil Supra树脂修复)35例、D组(Beautiful Flow Plus F03树脂修复)30例。手术治疗后随访6个月,比较4组患者牙髓活力、材料密合性、充填物表面磨损及充填物完好性情况。结果:术后6个月,4组患者牙髓活力均正常。A组、B组、C组、D组材料密合性好的患牙占比分别为75.49%、90.74%、88.57%、97.20%,A组低于B组、C组、D组,差异均有统计学意义(P<0.05);B组与D组、C组与D组比较,差异均有统计学意义(P<0.05),B、C组之间差异无统计学意义(P>0.05)。A组、B组、C组、D组充填物表面无磨损的患牙占比分别为77.45%、95.37%、94.29%、99.07%,A组占比低于B组、C组及D组,差异均有统计学意义(P<0.05);B组与C组、B组与D组、C组与D组间比较,差异均无统计学意义(P>0.05)。A组、B组、C组、D组充填物完好的患牙占比分别为91.18%、97.22%、97.14%、99.07%,A组占比低于D组,差异有统计学意义(P<0.05)。其他组之间比较,差异均无统计学意义(P>0.05)。结论:4种材料对牙髓活力均无影响,树脂类材料在密合性、表面磨损情况以及完好性上均优于Fuji IX GP玻璃离子水门汀。三种树脂类材料中Beautiful Flow Plus F03在密闭性方面优于其他两种树脂。展开更多
We present a short retrospective review of the existing literature about the dynamics of(dry)granular matter under the effect of vibrations.The main objective is the development of an integrated resource where vital i...We present a short retrospective review of the existing literature about the dynamics of(dry)granular matter under the effect of vibrations.The main objective is the development of an integrated resource where vital information about past findings and recent discoveries is provided in a single treatment.Special attention is paid to those works where successful synthetic routes to as-yet unknown phenomena were identified.Such landmark results are analyzed,while smoothly blending them with a history of the field and introducing possible categorizations of the prevalent dynamics.Although no classification is perfect,and it is hard to distillate general properties out of specific observations or realizations,two possible ways to interpret the existing results are defined according to the type of forcing or the emerging(ensuing)regime of motion.In particular,first results concerning the case where vibrations and gravity are concurrent(vertical shaking)are examined,then the companion situation with vibrations perpendicular to gravity(horizontal shaking)is described.Universality classes are introduced as follows:(1)Regimes where sand self-organizes leading to highly regular geometrical“pulsating”patterns(thin layer case);(2)Regimes where the material undergoes“fluidization”and develops an internal multicellular convective state(tick layers case);(3)Regimes where the free interface separating the sand from the overlying gas changes inclination or develops a kind a patterned configuration consisting of stable valleys and mountains or travelling waves;(4)Regimes where segregation is produced,i.e.,particles of a given size tend to be separated from the other grains(deep containers).Where possible,an analogy or parallelism is drawn with respect to the companion field of fluid-dynamics for which the assumption of“continuum”can be applied.展开更多
Aim of the present in vitro study is to evaluate the radiopacity levels of composite resins with various shades and viscosity.10 mm×2 mm discs were prepared from 7 condensable and 4 flowable composites(n=10).An a...Aim of the present in vitro study is to evaluate the radiopacity levels of composite resins with various shades and viscosity.10 mm×2 mm discs were prepared from 7 condensable and 4 flowable composites(n=10).An aluminum step wedge ranging from 2.0 to 10.0 mm in thickness was placed on the occlusal film.Digital radiographs were taken using a dental X-ray device and radiographic densities of each step of the aluminum wedge and the samples were recorded to the computer.Five readings were taken and means were calculated.One-Way Anova and Tamhane post hoc tests were performed.While G-eanial Posterior has the highest radiopacity value followed by Filtek Z550,Aelite Flo has the lowest radiopacity value.Posterior composites show higher radiopacity and flowable composites with higher filler loadings have superior radiopacity levels to condensable composites.Enamel and body shades of the composite brands have also statistically significant differences in radiopacity scores.Eventually,radiopacity level of a composite resin material is not affected by the size of fillers;however,the composition,shape and loading of the fillers can specify the radiodensity.展开更多
The flowability of five kinds of microencapsulation powders,with differentβ-carotene contents and by two alternative particle-forming technologies i.e.spray-drying and starch-catching beadlet technology,was meas- ure...The flowability of five kinds of microencapsulation powders,with differentβ-carotene contents and by two alternative particle-forming technologies i.e.spray-drying and starch-catching beadlet technology,was meas- ured.The actual flow properties of the five powders were compared based on bin-flow test,and three flow indexes (Hausner ratio,repose angle and flow index)were measured.It was found that the repose angle is the most suitable index to reflect the flowability of these powders for the particle properties would not be altered due to compaction or tapping during the measuring process.Particle size and particle size distribution play most important roles in the flowability of these granular materials,which was also influenced by other factors like shape,surface texture,sur- face roughness,etc.Microcapsules with wall material of gelatin and a layer of modified starch absorbed on the sur- face showed excellent flowabilities and good mechanical properties,and they are favorable for tabletting to supply β-carotene.展开更多
Effects of calcined coal gangue （CG） aggregates treated by the surface thermal activation on the flowability and strength, and paste-CG aggregate interfaces of the cement-based material were investigated. The experi...Effects of calcined coal gangue （CG） aggregates treated by the surface thermal activation on the flowability and strength, and paste-CG aggregate interfaces of the cement-based material were investigated. The experimental results show that the compressive and flexural strength of the cement-based material with the calcined CG aggregates is much higher than that of the material with the natural CG aggregates, but the flowability of the material with calcined CG is significantly reduced with the calcined time. The strength of the material with the calcined CG aggregates only increases little with the calcined time at the same w/c ratio, but is reduced with the calcined time at the same flowability. The CG aggregates calcined by the surface thermal activation obviously overcomes the disadvantages of fully calcined CG.展开更多
Ti-6 Al-4 V alloy powder was processed by electrode induction melting gas atomization(EIGA)at high gas pressure(5.5-7.0 MPa).The effects of atomizing gas pressure on the powder characteristics and the microstructure,a...Ti-6 Al-4 V alloy powder was processed by electrode induction melting gas atomization(EIGA)at high gas pressure(5.5-7.0 MPa).The effects of atomizing gas pressure on the powder characteristics and the microstructure,along with the mechanical properties of the as-fabricated block by laser melting deposition(LMD),were investigated.The results indicate that the diameters of powders are distributed in a wide range of sizes from 1 to 400μm,and the median powder size(d50)decreases with increasing gas pressure.The powders with a size fraction of 100-150μm obtained at gas pressures of 6.0 and 6.5 MPa have better flowability.The oxygen content is consistent with the change trend of gas pressure within a low range of 0.06%-0.20%.Specimens fabricated by LMD are mainly composed ofα+βgrains with a fine lamellar Widmanstatten structures and have the ultimate tensile strength(UTS)and yield strength of approximately 1100 and 1000 MPa,respectively.Furthermore,the atomized powders have a favorable 3 D printing capability,and the mechanical properties of Ti-6 Al-4 V alloys manufactured by LMD typically exceed those of their cast or wrought counterparts.展开更多
Spherical tungsten and titanium powders were prepared by radio frequency inductively coupled plasma torch with irregular shaped tungsten and titanium hydride （TiH2） powders, respectively. The effect of the feed rate...Spherical tungsten and titanium powders were prepared by radio frequency inductively coupled plasma torch with irregular shaped tungsten and titanium hydride （TiH2） powders, respectively. The effect of the feed rate on spheroidization efficiency was investigated. The phase composition, oxygen content, morphology, and particle size distribution of the powders before and after spheroidization were characterized by X-ray diffraction （XRD）, nitrogen/oxygen analyzer, scanning electron microscopy （SEM）, and laser micron sizer （LMS）. The results show that both kinds of plasma-processed powders have good dispersity, smooth surface, and single phase. A maximum of 100 % of spheroidization efficiency can be achieved at a lower feed rate. The spherical titanium powder obtained by the plasma treatment consists of particles with mean diameter of 33.34 gin, while the mean diameter of ori- ginal Till2 powder is 136.56 μm. The apparent density and flowability of the spherical tungsten powder are 6.3 g.cm-3 and 0.16 s.g-1, respectively. The apparent density and flowability of the spherical titanium powder are 2.8 g.cm-3 and 0.52 s.g-1, respectively. With the increase of the feed rate, the sphemidization efficiency of raw powders drops gradually.展开更多
Nanoparticles reinforced steels have many advantaged mechanical properties.Additive manufacturing offers a new method for fabricating nanoparticles reinforced high performance metal components.In this work,we report t...Nanoparticles reinforced steels have many advantaged mechanical properties.Additive manufacturing offers a new method for fabricating nanoparticles reinforced high performance metal components.In this work,we report the application of low energy ball milling in mixing nanoparticles and micron 316 L powder.With this method,0.3 and 1.0 wt% Y2 O3 nanoparticles can be uniformly distributed on the surface of 316 L powder with the parameters of ball-to-powder ratio at 1:1,speed at 90 rpm and 7 h of mixing.The matrix 316 L powders remain spherical in shape after the mixing process.In the meantime,the effect of low energy ball milling and the addition of Y2 O3 nanoparticles on the powder characteristics(flowability,apparent density and tap density) are also studied.Results show that the process of low energy ball milling itself can slightly decrease the flowability and apparent density of the 316 L powder.The addition of 0.3 and 1.0 wt% Y2 O3 nanoparticles can also decrease the flowability,the tap density and the apparent density compared with the original 316 L powder.All of these changes result from the rough surface of the mixed powder produced by ball milling and the addition of Y2 O3 nanoparticles.The powder’s rough surface can increase the coefficient of friction of powders.The mixture of 316 L powder and Y2 O3 nanoparticles can be successfully used for selective laser melting(SLM).The relative density of SLM 316 L-Y2 O3 is measured at 99.5%.However,Y2 O3 agglomerations were observed which is due to the poor wettability between 316 L and Y2 O3.展开更多
Circulating fluidized bed combustion （CFBC） ash can be potentially used as supplementary cementitious materials for concrete production due to its desirable pozzolanic activity. The adsorption properties of CFBC ash...Circulating fluidized bed combustion （CFBC） ash can be potentially used as supplementary cementitious materials for concrete production due to its desirable pozzolanic activity. The adsorption properties of CFBC ash-cement pastes were studied, and ordinary pulverized coal combustion （PCC） fly ash-cement pastes were used as control. The water-adsorption and superplasticizer （SP）-adsorption properties of the pastes were evaluated by water demand and UV-visible absorption spectroscopy respectively. The results show that CFBC ash-cement system has greater compressive strength as compared with PCC fly ash-cement system at a given curing age, although the water demand of the former is significantly higher than that of the latter. CFBC ash-cement pastes possess higher adsorption ability of aliphatic SP than PCC fly ash-cement pastes and the adsorption amount increases with an increase in ash replacement ratio. CFBC ash- cement pastes exhibit lower workability with higher slump loss. It is concluded that CFBC ash can be potentially used as supplementary cementitious material in concrete production, but the mix design of CFBC ash concrete needs to be appropriately adjusted. It is suggested that CFBC ash is used for the production of the concrete needing low flowability.展开更多
Thermal behavior and physical properties of castables during curing and drying-out are associated with their binding system. In this work, five alumina based （ Al2O3 〉 87% ） castables with different combinations of...Thermal behavior and physical properties of castables during curing and drying-out are associated with their binding system. In this work, five alumina based （ Al2O3 〉 87% ） castables with different combinations of binding materials, i. e. , （ 1 ） CA cement （CA） ＋ Reactive alumina （ RA ） ＋ H2O ; （ 2 ） high level addi- tion of CA ＋ Microsilica （MS） ＋ H2O ; （ 3 ） low level addition of CA ＋ MS ＋ H2O ; （4） MS ＋ Hydratable alumina ＋ H20 and （ 5 ） MS ＋ Magnesia ＋ H2O, respectively, have been investigated on the flowability and thermal behavior during curing at room temperature, drying at 110% and heating from 200℃ to 1000℃ at an interval of 100℃ , in terms of water addition, vibration flow value, porosity, dehydration, explosion resistance, cold and hot bending strengths. Differences in dehydrating behavior and the mentioned properties have been revealed and correlated to the binding system.展开更多
This paper investigated the effects of pre-heating treatment temperatures(T_(pre))on the flowability and wax deposition characteristics of a typical waxy crude oil after adding wax inhibitors.It is found that there is...This paper investigated the effects of pre-heating treatment temperatures(T_(pre))on the flowability and wax deposition characteristics of a typical waxy crude oil after adding wax inhibitors.It is found that there is little difference in wax precipitation exothermic characteristics of crude oils at different T_(pre),as well as the wax crystal solubility coefficient in the temperature range of 25-30℃.For the undoped crude oil,the flowability after wax precipitation gets much improved and the wax deposition is alleviated as T_(pre)increasing.At T_(pre)=50℃,the viscosity and wax deposition rate of crude oil adding wax inhibitors are higher than those of the undoped crude oil.When the T_(pre)increases to 60,70,and 80℃,the flowability of the doped crude oil are largely improved and the wax deposition is suppressed with the T_(pre)increase,but the wax content of wax deposit increases gradually.It is speculated that,on the one hand,the T_(pre)increase helps the dispersion of asphaltenes into smaller sizes,which facilitates the co-crystallization with paraffin waxes and generates more aggregated wax crystal flocs.This weakens the low-temperature gel structure and increases the solid concentration required for the crosslink to form the wax deposit.On the other hand,the decrease in viscosity increases the diffusion rate of wax molecules and accelerates the aging of wax deposits.The experimental results have important guiding significance for the pipeline transportation of doped crude oils.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
文摘One of the most challenging factors affecting impression quality and good marginal fit is the gingival retraction method, which aims to separate the gingiva from the tooth to expose the finishing line of the prepared tooth. Bleeding and contamination from the crevicular fluid may compete for space with the impression material within the sulcus, leading to indistinct preparations and a lack of detail at the margin. In addition, such procedures might damage the PDL and cause permanent recession. Flowable composite cable, as opposed to traditional retraction cords, offers the proper marginal seal and visibility during the impression record because of its lower viscosity, improved adaptability, and elastic properties. The aim of this report is to present a brand-new, innovative method for controlling gingival hemorrhage in addition to the gingival retraction in restorative and prosthodontic treatment by utilizing a flowable composite during the final impression record procedure. In these case reports, the flowable composite cord technique is used instead of traditional gingival cords to modify and refine the gingival tissue before taking the traditional final impression or digital scan. Two cases were done for patients undergoing fixed prosthodontics and veneer treatment within a 2-year follow-up period. In addition, the flowable composite cord was used as temporary restoration before the final prosthetic cementation or under the provisional crowns. As a result, clean and healthy gingival tissues render cementation of the final prosthesis quicker and easier to perform. The patients in both cases claimed that their prosthodontic treatments, which involved the application of a flowable composite cord to temporarily retraction the gingiva, had produced good outcomes at the yearlong follow-up. In conclusion, the flowable composite cord technique is found to be a useful tool to improve the quality of impressions in fixed prosthodontics by providing excellent access for impression material to record fine details of the finish line of the prepared tooth structure, and to alter the inflamed tissue into a healthy tissue.
基金supported by grants from the Fundamental Research Funds for the Central Universities, China (2572016DA02)the National Natural Science Foundation of China (31570642)the Science and Technology Innovation and Entrepreneurship Projects of Returned Overseas Personnel in Jilin Province, China (2013-36)
文摘A dry flowable formulation of Clonostachys rosea with fungicidal activity against Sclerotinia sclerotiorum was prepared by spray drying. The formulation was optimized by a four-factor, three-level orthogonal experiment to screen inert ingredients and spray-drying conditions. The optimal dry flowable formulation of C. rosea included 30% C. rosea （ratio of conidia powder and its fermentation broth is 1：3）, 3% Morwet EFW, 4% K12, 10% Morwet D425, 9% sodium salt of polynaphthalene sulphonic acid （NNO）, 5% croscarmellose sodium, 5% （NH4）2SO4, 0.5% carboxymethyl cellulose sodium （CMC-Na）, 1% oxalic acid and palygorskite （carrier） up to 100%. The formulation exhibited good physical characteristics, such as high dispersibility, viability and a long shelf life. Plate antagonism tests and pot trials indicated that the dry flowable formulation was very effective against S. sclerotiorum, with control efficiency of up to 88.30%. This dry flowable formulation of C. rosea is a new potential commercial fungicide for spray drying to control S. sclerotiorum.
文摘为满足高校办公信息化的个性化需求,缩短流程业务办理时间,针对传统操作方式任务繁重、效率低下的现状,介绍了业务流程建模注解BPMN(Business Process Modeling Notation),提出通过Flowable工作流引擎实现业务流程中的逻辑处理。通过请假申请流程对工作流的定义过程进行了分析,基于Flowable设计并实现了高校办公系统,使用表明能够满足高校办公需求。
文摘This research investigated the use of wood ash to partially replace cement or sand in conventional concrete, roller compacted concrete (RCC), and flowable fill. The main focus was to determine how the wood ash addition affected the main fresh and hardened properties of these materials. It was found that the wood ash could be successfully incorporated into the conventional concrete. In particular, the wood ash addition not only accelerated the setting, but also improved the early and the 28-day compressive strength of concrete that contained the blast furnace slag. It was also observed that the wood ash could be positively added into RCC to facilitate the compaction and reduce the risk of segregation. In addition, the wood ash can be beneficially introduced into the flowable fill mixtures to facilitate flow, to alleviate bleeding and subsidence, as well as to achieve controlled strength especially when combined with the class C or the class F fly ash.
文摘目的:比较Fuji IX GP玻璃离子水门汀、3M ESPE Filtek^(TM) Bulk Fill Flowable树脂、VOCO Polofil Supra树脂及Beautiful Flow Plus F03树脂修复根面龋的临床疗效。方法:选取后牙根面龋患者128例(422颗患牙),按照充填修复材料分为A组(Fuji IX GP玻璃离子水门汀修复)34例、B组(3M ESPE Filtek^(TM) Bulk Fill Flowable树脂修复)29例、C组(VOCO Polofil Supra树脂修复)35例、D组(Beautiful Flow Plus F03树脂修复)30例。手术治疗后随访6个月,比较4组患者牙髓活力、材料密合性、充填物表面磨损及充填物完好性情况。结果:术后6个月,4组患者牙髓活力均正常。A组、B组、C组、D组材料密合性好的患牙占比分别为75.49%、90.74%、88.57%、97.20%,A组低于B组、C组、D组,差异均有统计学意义(P<0.05);B组与D组、C组与D组比较,差异均有统计学意义(P<0.05),B、C组之间差异无统计学意义(P>0.05)。A组、B组、C组、D组充填物表面无磨损的患牙占比分别为77.45%、95.37%、94.29%、99.07%,A组占比低于B组、C组及D组,差异均有统计学意义(P<0.05);B组与C组、B组与D组、C组与D组间比较,差异均无统计学意义(P>0.05)。A组、B组、C组、D组充填物完好的患牙占比分别为91.18%、97.22%、97.14%、99.07%,A组占比低于D组,差异有统计学意义(P<0.05)。其他组之间比较,差异均无统计学意义(P>0.05)。结论:4种材料对牙髓活力均无影响,树脂类材料在密合性、表面磨损情况以及完好性上均优于Fuji IX GP玻璃离子水门汀。三种树脂类材料中Beautiful Flow Plus F03在密闭性方面优于其他两种树脂。
文摘We present a short retrospective review of the existing literature about the dynamics of(dry)granular matter under the effect of vibrations.The main objective is the development of an integrated resource where vital information about past findings and recent discoveries is provided in a single treatment.Special attention is paid to those works where successful synthetic routes to as-yet unknown phenomena were identified.Such landmark results are analyzed,while smoothly blending them with a history of the field and introducing possible categorizations of the prevalent dynamics.Although no classification is perfect,and it is hard to distillate general properties out of specific observations or realizations,two possible ways to interpret the existing results are defined according to the type of forcing or the emerging(ensuing)regime of motion.In particular,first results concerning the case where vibrations and gravity are concurrent(vertical shaking)are examined,then the companion situation with vibrations perpendicular to gravity(horizontal shaking)is described.Universality classes are introduced as follows:(1)Regimes where sand self-organizes leading to highly regular geometrical“pulsating”patterns(thin layer case);(2)Regimes where the material undergoes“fluidization”and develops an internal multicellular convective state(tick layers case);(3)Regimes where the free interface separating the sand from the overlying gas changes inclination or develops a kind a patterned configuration consisting of stable valleys and mountains or travelling waves;(4)Regimes where segregation is produced,i.e.,particles of a given size tend to be separated from the other grains(deep containers).Where possible,an analogy or parallelism is drawn with respect to the companion field of fluid-dynamics for which the assumption of“continuum”can be applied.
文摘Aim of the present in vitro study is to evaluate the radiopacity levels of composite resins with various shades and viscosity.10 mm×2 mm discs were prepared from 7 condensable and 4 flowable composites(n=10).An aluminum step wedge ranging from 2.0 to 10.0 mm in thickness was placed on the occlusal film.Digital radiographs were taken using a dental X-ray device and radiographic densities of each step of the aluminum wedge and the samples were recorded to the computer.Five readings were taken and means were calculated.One-Way Anova and Tamhane post hoc tests were performed.While G-eanial Posterior has the highest radiopacity value followed by Filtek Z550,Aelite Flo has the lowest radiopacity value.Posterior composites show higher radiopacity and flowable composites with higher filler loadings have superior radiopacity levels to condensable composites.Enamel and body shades of the composite brands have also statistically significant differences in radiopacity scores.Eventually,radiopacity level of a composite resin material is not affected by the size of fillers;however,the composition,shape and loading of the fillers can specify the radiodensity.
基金Supported by the National-Natural Science Foundation of China （No.20576118） and National High Technology Research and Development Program of China （863 Program, No.2006AA02Z210）.
文摘The flowability of five kinds of microencapsulation powders,with differentβ-carotene contents and by two alternative particle-forming technologies i.e.spray-drying and starch-catching beadlet technology,was meas- ured.The actual flow properties of the five powders were compared based on bin-flow test,and three flow indexes (Hausner ratio,repose angle and flow index)were measured.It was found that the repose angle is the most suitable index to reflect the flowability of these powders for the particle properties would not be altered due to compaction or tapping during the measuring process.Particle size and particle size distribution play most important roles in the flowability of these granular materials,which was also influenced by other factors like shape,surface texture,sur- face roughness,etc.Microcapsules with wall material of gelatin and a layer of modified starch absorbed on the sur- face showed excellent flowabilities and good mechanical properties,and they are favorable for tabletting to supply β-carotene.
基金Funded by the Major State Basic Research Development Program of China('973'Project,2001CB610705)
文摘Effects of calcined coal gangue （CG） aggregates treated by the surface thermal activation on the flowability and strength, and paste-CG aggregate interfaces of the cement-based material were investigated. The experimental results show that the compressive and flexural strength of the cement-based material with the calcined CG aggregates is much higher than that of the material with the natural CG aggregates, but the flowability of the material with calcined CG is significantly reduced with the calcined time. The strength of the material with the calcined CG aggregates only increases little with the calcined time at the same w/c ratio, but is reduced with the calcined time at the same flowability. The CG aggregates calcined by the surface thermal activation obviously overcomes the disadvantages of fully calcined CG.
基金Project(2017YFB0305801)supported by the National Key R&D Program of ChinaProject(U1508213)supported by the Joint-Fund of NSFC-Liaoning,ChinaProject(51771051)supported by the National Natural Science Foundation of China.
文摘Ti-6 Al-4 V alloy powder was processed by electrode induction melting gas atomization(EIGA)at high gas pressure(5.5-7.0 MPa).The effects of atomizing gas pressure on the powder characteristics and the microstructure,along with the mechanical properties of the as-fabricated block by laser melting deposition(LMD),were investigated.The results indicate that the diameters of powders are distributed in a wide range of sizes from 1 to 400μm,and the median powder size(d50)decreases with increasing gas pressure.The powders with a size fraction of 100-150μm obtained at gas pressures of 6.0 and 6.5 MPa have better flowability.The oxygen content is consistent with the change trend of gas pressure within a low range of 0.06%-0.20%.Specimens fabricated by LMD are mainly composed ofα+βgrains with a fine lamellar Widmanstatten structures and have the ultimate tensile strength(UTS)and yield strength of approximately 1100 and 1000 MPa,respectively.Furthermore,the atomized powders have a favorable 3 D printing capability,and the mechanical properties of Ti-6 Al-4 V alloys manufactured by LMD typically exceed those of their cast or wrought counterparts.
基金financially supported by the National Natural Science Foundation of China(No.51274039)the Research Fund for the Doctoral Program of Higher Education of China(No.20120006110007)
文摘Spherical tungsten and titanium powders were prepared by radio frequency inductively coupled plasma torch with irregular shaped tungsten and titanium hydride （TiH2） powders, respectively. The effect of the feed rate on spheroidization efficiency was investigated. The phase composition, oxygen content, morphology, and particle size distribution of the powders before and after spheroidization were characterized by X-ray diffraction （XRD）, nitrogen/oxygen analyzer, scanning electron microscopy （SEM）, and laser micron sizer （LMS）. The results show that both kinds of plasma-processed powders have good dispersity, smooth surface, and single phase. A maximum of 100 % of spheroidization efficiency can be achieved at a lower feed rate. The spherical titanium powder obtained by the plasma treatment consists of particles with mean diameter of 33.34 gin, while the mean diameter of ori- ginal Till2 powder is 136.56 μm. The apparent density and flowability of the spherical tungsten powder are 6.3 g.cm-3 and 0.16 s.g-1, respectively. The apparent density and flowability of the spherical titanium powder are 2.8 g.cm-3 and 0.52 s.g-1, respectively. With the increase of the feed rate, the sphemidization efficiency of raw powders drops gradually.
基金supported by A*STAR Industrial Additive Manufacturing Program:The A*STAR Additive Manufacturing Centre(AMC)Initiative:Work Package 1(High Temperature Mate-rials Development for 3D Additive Manufacturing,Grant No.1426800088)financial support from Nanyang Technological University。
文摘Nanoparticles reinforced steels have many advantaged mechanical properties.Additive manufacturing offers a new method for fabricating nanoparticles reinforced high performance metal components.In this work,we report the application of low energy ball milling in mixing nanoparticles and micron 316 L powder.With this method,0.3 and 1.0 wt% Y2 O3 nanoparticles can be uniformly distributed on the surface of 316 L powder with the parameters of ball-to-powder ratio at 1:1,speed at 90 rpm and 7 h of mixing.The matrix 316 L powders remain spherical in shape after the mixing process.In the meantime,the effect of low energy ball milling and the addition of Y2 O3 nanoparticles on the powder characteristics(flowability,apparent density and tap density) are also studied.Results show that the process of low energy ball milling itself can slightly decrease the flowability and apparent density of the 316 L powder.The addition of 0.3 and 1.0 wt% Y2 O3 nanoparticles can also decrease the flowability,the tap density and the apparent density compared with the original 316 L powder.All of these changes result from the rough surface of the mixed powder produced by ball milling and the addition of Y2 O3 nanoparticles.The powder’s rough surface can increase the coefficient of friction of powders.The mixture of 316 L powder and Y2 O3 nanoparticles can be successfully used for selective laser melting(SLM).The relative density of SLM 316 L-Y2 O3 is measured at 99.5%.However,Y2 O3 agglomerations were observed which is due to the poor wettability between 316 L and Y2 O3.
基金the National Nature Science Foundation of China （51272222）.
文摘Circulating fluidized bed combustion （CFBC） ash can be potentially used as supplementary cementitious materials for concrete production due to its desirable pozzolanic activity. The adsorption properties of CFBC ash-cement pastes were studied, and ordinary pulverized coal combustion （PCC） fly ash-cement pastes were used as control. The water-adsorption and superplasticizer （SP）-adsorption properties of the pastes were evaluated by water demand and UV-visible absorption spectroscopy respectively. The results show that CFBC ash-cement system has greater compressive strength as compared with PCC fly ash-cement system at a given curing age, although the water demand of the former is significantly higher than that of the latter. CFBC ash-cement pastes possess higher adsorption ability of aliphatic SP than PCC fly ash-cement pastes and the adsorption amount increases with an increase in ash replacement ratio. CFBC ash- cement pastes exhibit lower workability with higher slump loss. It is concluded that CFBC ash can be potentially used as supplementary cementitious material in concrete production, but the mix design of CFBC ash concrete needs to be appropriately adjusted. It is suggested that CFBC ash is used for the production of the concrete needing low flowability.
文摘Thermal behavior and physical properties of castables during curing and drying-out are associated with their binding system. In this work, five alumina based （ Al2O3 〉 87% ） castables with different combinations of binding materials, i. e. , （ 1 ） CA cement （CA） ＋ Reactive alumina （ RA ） ＋ H2O ; （ 2 ） high level addi- tion of CA ＋ Microsilica （MS） ＋ H2O ; （ 3 ） low level addition of CA ＋ MS ＋ H2O ; （4） MS ＋ Hydratable alumina ＋ H20 and （ 5 ） MS ＋ Magnesia ＋ H2O, respectively, have been investigated on the flowability and thermal behavior during curing at room temperature, drying at 110% and heating from 200℃ to 1000℃ at an interval of 100℃ , in terms of water addition, vibration flow value, porosity, dehydration, explosion resistance, cold and hot bending strengths. Differences in dehydrating behavior and the mentioned properties have been revealed and correlated to the binding system.
基金The authors thank the financial support from the National Natural Science Foundation of China(51904327,U19B2012)China University of Petroleum Innovation Project(22CX06050A).
文摘This paper investigated the effects of pre-heating treatment temperatures(T_(pre))on the flowability and wax deposition characteristics of a typical waxy crude oil after adding wax inhibitors.It is found that there is little difference in wax precipitation exothermic characteristics of crude oils at different T_(pre),as well as the wax crystal solubility coefficient in the temperature range of 25-30℃.For the undoped crude oil,the flowability after wax precipitation gets much improved and the wax deposition is alleviated as T_(pre)increasing.At T_(pre)=50℃,the viscosity and wax deposition rate of crude oil adding wax inhibitors are higher than those of the undoped crude oil.When the T_(pre)increases to 60,70,and 80℃,the flowability of the doped crude oil are largely improved and the wax deposition is suppressed with the T_(pre)increase,but the wax content of wax deposit increases gradually.It is speculated that,on the one hand,the T_(pre)increase helps the dispersion of asphaltenes into smaller sizes,which facilitates the co-crystallization with paraffin waxes and generates more aggregated wax crystal flocs.This weakens the low-temperature gel structure and increases the solid concentration required for the crosslink to form the wax deposit.On the other hand,the decrease in viscosity increases the diffusion rate of wax molecules and accelerates the aging of wax deposits.The experimental results have important guiding significance for the pipeline transportation of doped crude oils.
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.
