Purpose: The study investigated the impact of dietary habits, specifically soda, milk kefir, water kefir, almond milk, and distilled water (control) consumption, on the microhardness of gingiva-coloured composite and ...Purpose: The study investigated the impact of dietary habits, specifically soda, milk kefir, water kefir, almond milk, and distilled water (control) consumption, on the microhardness of gingiva-coloured composite and acrylic denture bases. Methods: Materials included gingiva-coloured composite (Fusion Universal G1), acrylic (Imicryl), and subdivided Procryla group. Subgroups comprised 15 and 30-minute heat polymerized (Pro15, Pro30), and 1 wt% (Pro1Z) and 3 wt% (Pro3Z) zirconium added groups. Immersed in beverages for 1, 7, and 14 days, pH and microhardness were assessed. SEM examined random samples. Statistical analysis used repeated measures ANOVA, and post hoc tests (p Results: The gingiva-coloured composites displayed noteworthy time-associated microhardness changes (p 0.05). Despite variable pH levels in beverages, no substantial group interaction effects were observed (p > 0.05). Initial microhardness rankings shifted after a 14-day immersion. Conclusions: Gingiva-coloured composite exhibited the highest microhardness pre- and post-immersion, followed by Procryla30 and Imicryl groups. .展开更多
The paper presents laboratory test results on hydraulically bound road base materials containing high volume of steel slag and blast furnace slag waste dusts compared with control mixtures. These mixtures contain high...The paper presents laboratory test results on hydraulically bound road base materials containing high volume of steel slag and blast furnace slag waste dusts compared with control mixtures. These mixtures contain higher levels of (4mm-0.0 mm) dust, than would be the case in standard un bound road base mixtures. The combined influence of the steel slag and granulated blast furnace slag wastes content is to enhance the stiffness of the road base materials and save materials and cost during road construction. Triaxial repeated load tests were performed on the unbound and lightly bound materials to measure their resilient modulus. The test results show important improvements in the bond strength between the contents of road base materials. This offers the prospect of using these materials in road base materials to reduce the use of primary aggregates and thus minimize the cost of roads and highways construction.展开更多
In order to assess the responses of different skin types stimulated by tape stripping,after which two kinds of brand cosmetics of cream and hydrogel,were separately applied to evaluate the individual soothing effect o...In order to assess the responses of different skin types stimulated by tape stripping,after which two kinds of brand cosmetics of cream and hydrogel,were separately applied to evaluate the individual soothing effect of the product on different skin types.A total of 30 volunteers aged 18~65 years were recruited,which were divided into four groups(oily,dry,normal and combined)according to the self-oiling ability of facial and T zones.Four 3 cm×3 cm of skins on inner forearm of each volunteer were chosen and randomly marked as blank,negative control,soothing cream and soothing gel.The blank area was kept untreated,and the remaining areas were tape-stripped by 10 times(Transparent universal 1527C-1,3M China Co.,Ltd.,)to disrupt the skin corneum and induce erythema.Images,erythema index(EI)and transcutaneous water loss rate(TEWL)of the marked skin areas before and 5 min after tape-stripping were taken to assess the distinct responses of different skin type to the taping treatment;Ten minutes after tape-stripping,The soothing products were applied to the test area,the skin images,EI and TEWL at 20 min and 50 min(corresponding to 30 min and 60 min after tape-stripping,respectively)were measured after cosmetics application to compare and evaluate the soothing effects of cream and hydrogel on different skin types.Results showed that different skin displayed diverse reactions to the tape-stripping,and the oily skin was more sensitive with longer duration of erythema than other skin types.After the application of soothing products,both cream and hydrogel could relieve skin erythema,while the soothing effects are dependent both on skin types and the cosmetic base materials:Hydrogel has a better efficacy in alleviating erythema and TEWL of dry skin,while the cream was more effective on normal,oily and combined skin types.The results suggest that the modelling method for soothing evaluation should consider the skin types of the volunteers,and the cosmetics of different base materials might have the target skin types.展开更多
The shortage of fresh water in the world has brought upon a serious crisis to human health and economic development.Solar‐driven interfacial photothermal conversion water evaporation including evaporating seawater,la...The shortage of fresh water in the world has brought upon a serious crisis to human health and economic development.Solar‐driven interfacial photothermal conversion water evaporation including evaporating seawater,lake water,or river water has been recognized as an environmentally friendly process for obtaining clean water in a low‐cost way.However,water transport is restricted by itself by solar energy absorption capacity's limits,especially for finite evaporation rates and insufficient working life.Therefore,it is important to seek photothermal conversion materials that can efficiently absorb solar energy and reasonably design solar‐driven interfacial photothermal conversion water evaporation devices.This paper reviews the research progress of carbon‐based photothermal conversion materials and the mechanism for solar‐driven interfacial photothermal conversion water evaporation,as well as the summary of the design and development of the devices.Based on the research progress and achievements of photothermal conversion materials and devices in the fields of seawater desalination and photothermal electric energy generation in recent years,the challenges and opportunities faced by carbon‐based photothermal conversion materials and devices are discussed.The prospect of the practical application of solar‐driven interfacial photothermal conversion evaporation technology is foreseen,and theoretical guidance is provided for the further development of this technology.展开更多
High performance aluminosilicate based cementitious materials were produced using calcined gangue as one of the major raw materials. The gangue was calcined at 500℃. The main constituent was calcined gangue, fly ash ...High performance aluminosilicate based cementitious materials were produced using calcined gangue as one of the major raw materials. The gangue was calcined at 500℃. The main constituent was calcined gangue, fly ash and slag, while alkali-silicate solutions were used as the diagenetic agent. The structure of gangue-containing aluminosilicate based cementitious materials was studied by the methods of IR, NMR and SEM. The results show that the mechanical properties are affected by the mass ratio between the gangue, slag and fly ash, the kind of activator and additional salt. For 28-day curing time, the compressive strength of the sample with a mass proportion of 2:1:1 (gangue: slag: fly ash) is 58.9 MPa, while the compressive strength of the sample containing 80wt% gangue can still be up to 52.3 MPa. The larger K^+ favors the formation of large silicate oligomers with which AI(OH)4- prefers to bind. Therefore, in Na-K compounding activator solutions more oligomers exist which result in a stronger compressive strength of aluminosilicate-based cementitious materials than in the case of Na-containing activator. The reasons for this were found through IR and NMR analysis. Glauber's salt reduces the 3-day compressive strength of the paste, but increases its 7-day and 28-day compressive strengths.展开更多
Combined with DTG analysis, X-Ray diffraction analysis (XRD) and field emission scanning electron microscopy analysis (FSEM) affiliated with energy dispersive spectrometer analysis (EDS), the early hydration and...Combined with DTG analysis, X-Ray diffraction analysis (XRD) and field emission scanning electron microscopy analysis (FSEM) affiliated with energy dispersive spectrometer analysis (EDS), the early hydration and carbonation behavior of cement paste compacts incorporated with 30% of dolomite powder at low water to cement ratio (0.15) was investigated. The results showed that early carbonation curing was capable of developing rapid early strength. It is noted that the carbonation duration should be strictly controlled otherwise subsequent hydration might be hindered. Dolomite powder acted as nuclei of crystallization, resulting in acceleration of products formation and refinement of products crystal size. Therefore, as for cement-based material, it was found that early carbonation could reduce cement dosages to a large extent and promote rapid strength gain resulting from rapid formation of products, supplemental enhancement due to water release in the reaction of carbonation, and formation ofnanometer CaCO3 skeleton network at early age.展开更多
High lattice match growth of InAsSb based materials on GaSb substrates is demonstrated. The present results indicate that a stable substrate temperature and the optimal flux ratios are of critical importance in achiev...High lattice match growth of InAsSb based materials on GaSb substrates is demonstrated. The present results indicate that a stable substrate temperature and the optimal flux ratios are of critical importance in achieving a homogeneous InAsSb based material composition throughout the growth period. The quality of these epilayers is assessed using a high-resolution x-ray diffraction and atomic force microscope. The mismatch between the GaSb substrate and InAsSb alloy achieves almost zero, and the rms surface roughness of InAsSb alloy achieves around 1.7A over an area of 28μm × 28μm. At the same time, the mismatches between GaSb and InAs/InAs0.73Sb0.27 superlattices (SLs) achieve approximately 100 arcsec (75 periods) and zero (300 periods), with the surface rms roughnesses of InAs/InAs0.73Sb0.27 SLs around 1.8 A (75 periods) and 2.1A (300 periods) over an area of 20 μm×20 μm, respectively. After fabrication and characterization of the devices, the dynamic resistance of the n-barrier-n InAsSb photodetector near zero bias is of the order of 10^6Ω·cm^2. At 77K, the positive-intrinsic-negative photodetectors are demonstrated in InAsSb and InAs/InAsSb SL (75 periods) materials, exhibiting fifty-percent cutoff wavelengths of 3.8μm and 5.1μm, respectively.展开更多
The properties of road base course materials of granular soils stabilized by AGS granular soil stabilizing cement were studied.The AGS cement has an expansibility to a certain degree,so the dry shrinkage of AGS cemen...The properties of road base course materials of granular soils stabilized by AGS granular soil stabilizing cement were studied.The AGS cement has an expansibility to a certain degree,so the dry shrinkage of AGS cement paste and AGS stabilized granular is much lower than that of Portland slag cement.AGS has a good suitability to granular soils.Granular soils stabilized by AGS have a much higher strength than that of soils stabilized by P S cement.The same strength can be reached with 20% reduction of cement dosage for AGS cement.And their elastic and resilient modulus are similar,but the former has a much higher tensile splitting strength,so the AGS stabilized granular has a much better anti-cracking performance than that of the P S stabilized granular.The reduced value of the strength and the density with the retard time for the granular soils stabilized by AGS is lower than that for P S cement.展开更多
ZnFe 2O 4 and ZnFe 2O 4 based materials were tested to obtain the electrical conductivity and corrosion resistance in melting bath for aluminum electrolysis. The results proved that adequate additives, such as Ni 2O 3...ZnFe 2O 4 and ZnFe 2O 4 based materials were tested to obtain the electrical conductivity and corrosion resistance in melting bath for aluminum electrolysis. The results proved that adequate additives, such as Ni 2O 3 CuO, Cu, ZnO and CeO 2 would increase the electrical conductivity, and the ZnFe 2O 4 based anodes with these additives were of good corrosion resistance. The current density on anode, the mole ratio of NaF/AlF 3 (MR) and the content of alumina in the bath effect the anode corrosion rate in different way.展开更多
A New method,named atmospheric pressure plasma polishing,for the ultra-smooth machining of the silicon based materials is introduced.By inputting the CF4 gas into the atmospheric pressure plasma flame,high density rea...A New method,named atmospheric pressure plasma polishing,for the ultra-smooth machining of the silicon based materials is introduced.By inputting the CF4 gas into the atmospheric pressure plasma flame,high density reactive radicals will be generated,which will then react with the silicon based materials.The reaction product is the vaporization of the SiF4,which can be easily processed.In this way,the atomic scale material removal can be realized and the defect free ultra-smooth surface can be obtained.An experimental setup is built up,and the SiC polishing experiment is carried out.The AFM test result shows that the finished surface roughness (Ra) can be improved from 4.529 nm to 0.926 nm in 3 minutes.展开更多
Material growth and device fabrication of the first 1.3μm quantum well (QW) edge emitting laser diodes in China are reported. Through the optimization of the molecular beam epitaxy (MBE) growth conditions and the...Material growth and device fabrication of the first 1.3μm quantum well (QW) edge emitting laser diodes in China are reported. Through the optimization of the molecular beam epitaxy (MBE) growth conditions and the tuning of the indium and nitrogen composition of the GalnNAs QWs, the emission wavelengths of the QWs can be tuned to 1.3μm. Ridge geometry waveguide laser diodes are fabricated. The lasing wavelength is 1.3μm under continuous current injection at room temperature with threshold current of 1kA/cm^2 for the laser diode structures with the cleaved facet mirrors. The output light power over 30mW is obtained.展开更多
Poly (methyl methacrylate) is widely used as denture base material. During fabrication of a denture, the physical and mechanical properties are influenced by cure condition. Each cure cycle or fabrication technique ...Poly (methyl methacrylate) is widely used as denture base material. During fabrication of a denture, the physical and mechanical properties are influenced by cure condition. Each cure cycle or fabrication technique is attempts to optimize the properties for a given application. The aim of this study was to compare two types of commercially available denture base materials (heat-cure and self-cure) in their mechanical properties. The samples were prepared according to the daily routine work for sample preparation in dental laboratories. After reaching dough stage the mix packed into dumbbell shaped of stainless steel mould and pressed in a hydraulic bench press for 25 mins at room temperature. For heat cure the polymerization cycle was carried out using water bath, while self cure was done at room temperature. The impact strength was evaluated using Charpy impact test. The hardness test was conducted using a calibrated Vickers hardness tester machine. The lowest impact strength was observed in self-cure denture base material (self cure material 6.2 kJ/m^2 while heat cure 12.69 kJ/m^2. It appears that the tendency of heat cure to fracture was lower than self-cure denture base materials. Heat cure denture base material has significantly higher hardness test values than self-cure denture base material. The observed VHN value of the heat-cure was 20.09 g/mm^2 while the self-cure value was 12.7 g/mm^2. This is may be due to the plasticizer effect of residual monomer which was higher in self curing material as reported in previous work. Generally, the heat cure material showed better properties compared to self cure material.展开更多
Competitive absorption processes, i.e. condensation, of water and essential oils (EO) are predominantly controlled by extent of condensation of diffusing water and EO molecules with marginal influence of porose ligno-...Competitive absorption processes, i.e. condensation, of water and essential oils (EO) are predominantly controlled by extent of condensation of diffusing water and EO molecules with marginal influence of porose ligno-cellulosic matter and a sort of EO. With increase of absorption the diffusion is depressed and vice versa. Diffusion of water molecules through porose system is usually slower in comparison with other molecules. It was discovered that a presence of EO decreases paper web humidity with increasing influence in environment with high relative air humidity. Likely, fast diffusing EO molecules decrease the ability of water molecules condensed in all accessible pores particularly in the non-penetrable pores.展开更多
Lithium ion battery (LIB) is one of the promising power storage devices in today’s world. Lithium ion battery like other types of electrochemical cell has anodic and cathodic electrode in which lithium ion is interca...Lithium ion battery (LIB) is one of the promising power storage devices in today’s world. Lithium ion battery like other types of electrochemical cell has anodic and cathodic electrode in which lithium ion is intercalated and deinterclated during charging and discharging process respectively. The capacity of lithium ion battery is improved by the development of innovative kinds of electrode. Carbon, metal/semiconductor, metal oxides and metal phosphides/ nitrides/sulfides based nanomaterials improve the capability of LIBs due to their high surface area, low diffusion distance, high electrical and ionic conductivity. Nanostructured materials represent a rapidly growing area in the field of Li-ion batteries because of their substantial advantages in terms of mass transport. In this review anode nanomaterials classified based on type of transition metal/semiconductor such as carbon, silicon, titanium and tin based nanomaterials are discussed. Additionally, different electrochemical reactions, comparative influence of anode materials on LIBs and their applications are widely explained.展开更多
The interaction of Si anions with Al sites during the hydration process was observed by NMR, IR and SEM to understand the reaction mechanism of the hydrates formation mixed with oil shale calcined at different tempera...The interaction of Si anions with Al sites during the hydration process was observed by NMR, IR and SEM to understand the reaction mechanism of the hydrates formation mixed with oil shale calcined at different temperatures. As the reaction progressed, the coordination of Al (Ⅳ, Ⅴ, and Ⅵ) changed almost completely to Ⅳ, when mixed with oil shale calcined at 700 ℃. However, when mixed with oil shale calcined at 400 ℃, some 6-coordination of Al still remained in the hydrates. Under the function of alkaline solutions, which were produced with the hydration of clinker, a certain amount of Si and Al atoms dissolved or hydrolyzed from aluminosilicate, formed geomonomers in solutions, and then polycondensed to form networks.展开更多
Statement of problem: Many processes have been applied to improve the fracture resistance of acrylic resin dentures by reinforcing them. The maximum goal of any denture repair is to restore the main strength of the de...Statement of problem: Many processes have been applied to improve the fracture resistance of acrylic resin dentures by reinforcing them. The maximum goal of any denture repair is to restore the main strength of the denture and to avoid further fracture. Purpose: This study investigated the ability of self-curing acrylic resin to be strength and deflection of repaired acrylic resin joints reinforced with various reinforcement materials to resist fracture. Material and methods: Transverse strength of polymethyl methacrylate acrylic resin reinforced with glass fiber mesh, metal mesh, and metal wire was evaluated with a 3-point load test on 40 intact specimens (n = 10 for control group) (n = 10 per each reinforcement material group). Fractured joint margins were rounded, a 4-mm gap was placed between them, and then they were repaired with autopolymerizing acrylic resin and retested. Results: Transverse strength for the polymethyl methacrylate acrylic resin samples has showed fracture at the side of sample rather than in the middle area of reinforcement materials and some other samples showed bending statue rather than fracture. Conclusion: Reinforcement with glass fiber mesh, metal mesh, and metal wire produced transverse strength in the side area of resin denture base material rather than in the middle of reinforcement area with bending samples rather than fracture response.展开更多
The evolution of self organized Ge quantum dots structure is investigated by scanning tunneling microscopy and atomic force microscopy during annealing treatment up to 700℃ in an ultra high vacuum(UHV) system.When t...The evolution of self organized Ge quantum dots structure is investigated by scanning tunneling microscopy and atomic force microscopy during annealing treatment up to 700℃ in an ultra high vacuum(UHV) system.When the sample temperature rises to 630℃,a great amount of new dots emerge on the wetting layer,which are believed to be incoherent islands compared with the dislocation free coherent islands formed during molecular beam epitaxy growth.展开更多
More than 4000 papers in the field of Mg and Mg alloys were published and indexed in Web of Science(WoS)Core Collection database in 2021.The bibliometric analyses indicate that the microstructure,mechanical properties...More than 4000 papers in the field of Mg and Mg alloys were published and indexed in Web of Science(WoS)Core Collection database in 2021.The bibliometric analyses indicate that the microstructure,mechanical properties,and corrosion of Mg alloys still are the main research focus.Mg ion batteries and hydrogen storage Mg materials have attracted much attention.Significant contributions to the research and development of magnesium alloys were made by Chongqing University,Shanghai Jiaotong University,and Chinese Academy of Sciences in China,Helmholtz Zentrum Hereon in Germany,Ohio State University in the United States,the University of Queensland in Australia,Kumanto University in Japan,and Seoul National University in Korea,University of Tehran in Iran,etc..This review is aimed to summarize the progress in the development of structural and functional Mg and Mg alloys in 2021.Based on the issues and challenges identified here,some future research directions are suggested.展开更多
Hydrogenated amorphous silicon carbide (a-SixC1-x:H) films were grown on Si substrate by plasma-enhanced chemical vapor deposition. Fixed flow rate of H2 and different flow ratio of SiHJCH4 were used. Er-doped a-Si...Hydrogenated amorphous silicon carbide (a-SixC1-x:H) films were grown on Si substrate by plasma-enhanced chemical vapor deposition. Fixed flow rate of H2 and different flow ratio of SiHJCH4 were used. Er-doped a-SixC1-x : H (a-SixC1-x-H :Er) films were prepared by implanting Er into the a- Si,C1-x-H host materials followed by annealing at different temperatures. The structure properties of the films were characterized by X-ray photoelectron spectroscopy (XPS), Raman spectra. infrared absorption Photoluminescence spectra (IR) and (PL) intensities depending on flow rates and annealing temperatures were studied. High annealing temperature is not favorable for PL because of C-surface segregation. It is shown that thermal quenching of this material is small by comparing the PL intensities of a-SixC1-x-H: Er at room temperature and low temperature.展开更多
文摘Purpose: The study investigated the impact of dietary habits, specifically soda, milk kefir, water kefir, almond milk, and distilled water (control) consumption, on the microhardness of gingiva-coloured composite and acrylic denture bases. Methods: Materials included gingiva-coloured composite (Fusion Universal G1), acrylic (Imicryl), and subdivided Procryla group. Subgroups comprised 15 and 30-minute heat polymerized (Pro15, Pro30), and 1 wt% (Pro1Z) and 3 wt% (Pro3Z) zirconium added groups. Immersed in beverages for 1, 7, and 14 days, pH and microhardness were assessed. SEM examined random samples. Statistical analysis used repeated measures ANOVA, and post hoc tests (p Results: The gingiva-coloured composites displayed noteworthy time-associated microhardness changes (p 0.05). Despite variable pH levels in beverages, no substantial group interaction effects were observed (p > 0.05). Initial microhardness rankings shifted after a 14-day immersion. Conclusions: Gingiva-coloured composite exhibited the highest microhardness pre- and post-immersion, followed by Procryla30 and Imicryl groups. .
文摘The paper presents laboratory test results on hydraulically bound road base materials containing high volume of steel slag and blast furnace slag waste dusts compared with control mixtures. These mixtures contain higher levels of (4mm-0.0 mm) dust, than would be the case in standard un bound road base mixtures. The combined influence of the steel slag and granulated blast furnace slag wastes content is to enhance the stiffness of the road base materials and save materials and cost during road construction. Triaxial repeated load tests were performed on the unbound and lightly bound materials to measure their resilient modulus. The test results show important improvements in the bond strength between the contents of road base materials. This offers the prospect of using these materials in road base materials to reduce the use of primary aggregates and thus minimize the cost of roads and highways construction.
文摘In order to assess the responses of different skin types stimulated by tape stripping,after which two kinds of brand cosmetics of cream and hydrogel,were separately applied to evaluate the individual soothing effect of the product on different skin types.A total of 30 volunteers aged 18~65 years were recruited,which were divided into four groups(oily,dry,normal and combined)according to the self-oiling ability of facial and T zones.Four 3 cm×3 cm of skins on inner forearm of each volunteer were chosen and randomly marked as blank,negative control,soothing cream and soothing gel.The blank area was kept untreated,and the remaining areas were tape-stripped by 10 times(Transparent universal 1527C-1,3M China Co.,Ltd.,)to disrupt the skin corneum and induce erythema.Images,erythema index(EI)and transcutaneous water loss rate(TEWL)of the marked skin areas before and 5 min after tape-stripping were taken to assess the distinct responses of different skin type to the taping treatment;Ten minutes after tape-stripping,The soothing products were applied to the test area,the skin images,EI and TEWL at 20 min and 50 min(corresponding to 30 min and 60 min after tape-stripping,respectively)were measured after cosmetics application to compare and evaluate the soothing effects of cream and hydrogel on different skin types.Results showed that different skin displayed diverse reactions to the tape-stripping,and the oily skin was more sensitive with longer duration of erythema than other skin types.After the application of soothing products,both cream and hydrogel could relieve skin erythema,while the soothing effects are dependent both on skin types and the cosmetic base materials:Hydrogel has a better efficacy in alleviating erythema and TEWL of dry skin,while the cream was more effective on normal,oily and combined skin types.The results suggest that the modelling method for soothing evaluation should consider the skin types of the volunteers,and the cosmetics of different base materials might have the target skin types.
基金Natural Science Foundation of Shandong Province,Grant/Award Number:ZR2019MB019National Natural Science Foundation of China,Grant/Award Numbers:22075122,52071295Research Foundation for Talented Scholars of Linyi University,Grant/Award Number:Z6122010。
文摘The shortage of fresh water in the world has brought upon a serious crisis to human health and economic development.Solar‐driven interfacial photothermal conversion water evaporation including evaporating seawater,lake water,or river water has been recognized as an environmentally friendly process for obtaining clean water in a low‐cost way.However,water transport is restricted by itself by solar energy absorption capacity's limits,especially for finite evaporation rates and insufficient working life.Therefore,it is important to seek photothermal conversion materials that can efficiently absorb solar energy and reasonably design solar‐driven interfacial photothermal conversion water evaporation devices.This paper reviews the research progress of carbon‐based photothermal conversion materials and the mechanism for solar‐driven interfacial photothermal conversion water evaporation,as well as the summary of the design and development of the devices.Based on the research progress and achievements of photothermal conversion materials and devices in the fields of seawater desalination and photothermal electric energy generation in recent years,the challenges and opportunities faced by carbon‐based photothermal conversion materials and devices are discussed.The prospect of the practical application of solar‐driven interfacial photothermal conversion evaporation technology is foreseen,and theoretical guidance is provided for the further development of this technology.
基金This work was supported by the National High-Tech Research and Development Program of China (No.2003AA332020), the Nation-al Natural Science Foundation of China (No.50474002) and the Key Project of the Ministry of Education of China (No.104231).
文摘High performance aluminosilicate based cementitious materials were produced using calcined gangue as one of the major raw materials. The gangue was calcined at 500℃. The main constituent was calcined gangue, fly ash and slag, while alkali-silicate solutions were used as the diagenetic agent. The structure of gangue-containing aluminosilicate based cementitious materials was studied by the methods of IR, NMR and SEM. The results show that the mechanical properties are affected by the mass ratio between the gangue, slag and fly ash, the kind of activator and additional salt. For 28-day curing time, the compressive strength of the sample with a mass proportion of 2:1:1 (gangue: slag: fly ash) is 58.9 MPa, while the compressive strength of the sample containing 80wt% gangue can still be up to 52.3 MPa. The larger K^+ favors the formation of large silicate oligomers with which AI(OH)4- prefers to bind. Therefore, in Na-K compounding activator solutions more oligomers exist which result in a stronger compressive strength of aluminosilicate-based cementitious materials than in the case of Na-containing activator. The reasons for this were found through IR and NMR analysis. Glauber's salt reduces the 3-day compressive strength of the paste, but increases its 7-day and 28-day compressive strengths.
基金Funded by the National Key Research Program(973 Program)(No.2013CB035901)the National Natural Science Foundation of China(No.51379163)
文摘Combined with DTG analysis, X-Ray diffraction analysis (XRD) and field emission scanning electron microscopy analysis (FSEM) affiliated with energy dispersive spectrometer analysis (EDS), the early hydration and carbonation behavior of cement paste compacts incorporated with 30% of dolomite powder at low water to cement ratio (0.15) was investigated. The results showed that early carbonation curing was capable of developing rapid early strength. It is noted that the carbonation duration should be strictly controlled otherwise subsequent hydration might be hindered. Dolomite powder acted as nuclei of crystallization, resulting in acceleration of products formation and refinement of products crystal size. Therefore, as for cement-based material, it was found that early carbonation could reduce cement dosages to a large extent and promote rapid strength gain resulting from rapid formation of products, supplemental enhancement due to water release in the reaction of carbonation, and formation ofnanometer CaCO3 skeleton network at early age.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11474248,61176127,61006085,61274013 and 61306013the Key Program for International S&T Cooperation Projects of China under Grant No 2011DFA62380the Ph.D. Programs Foundation of the Ministry of Education of China under Grant No 20105303120002
文摘High lattice match growth of InAsSb based materials on GaSb substrates is demonstrated. The present results indicate that a stable substrate temperature and the optimal flux ratios are of critical importance in achieving a homogeneous InAsSb based material composition throughout the growth period. The quality of these epilayers is assessed using a high-resolution x-ray diffraction and atomic force microscope. The mismatch between the GaSb substrate and InAsSb alloy achieves almost zero, and the rms surface roughness of InAsSb alloy achieves around 1.7A over an area of 28μm × 28μm. At the same time, the mismatches between GaSb and InAs/InAs0.73Sb0.27 superlattices (SLs) achieve approximately 100 arcsec (75 periods) and zero (300 periods), with the surface rms roughnesses of InAs/InAs0.73Sb0.27 SLs around 1.8 A (75 periods) and 2.1A (300 periods) over an area of 20 μm×20 μm, respectively. After fabrication and characterization of the devices, the dynamic resistance of the n-barrier-n InAsSb photodetector near zero bias is of the order of 10^6Ω·cm^2. At 77K, the positive-intrinsic-negative photodetectors are demonstrated in InAsSb and InAs/InAsSb SL (75 periods) materials, exhibiting fifty-percent cutoff wavelengths of 3.8μm and 5.1μm, respectively.
文摘The properties of road base course materials of granular soils stabilized by AGS granular soil stabilizing cement were studied.The AGS cement has an expansibility to a certain degree,so the dry shrinkage of AGS cement paste and AGS stabilized granular is much lower than that of Portland slag cement.AGS has a good suitability to granular soils.Granular soils stabilized by AGS have a much higher strength than that of soils stabilized by P S cement.The same strength can be reached with 20% reduction of cement dosage for AGS cement.And their elastic and resilient modulus are similar,but the former has a much higher tensile splitting strength,so the AGS stabilized granular has a much better anti-cracking performance than that of the P S stabilized granular.The reduced value of the strength and the density with the retard time for the granular soils stabilized by AGS is lower than that for P S cement.
文摘ZnFe 2O 4 and ZnFe 2O 4 based materials were tested to obtain the electrical conductivity and corrosion resistance in melting bath for aluminum electrolysis. The results proved that adequate additives, such as Ni 2O 3 CuO, Cu, ZnO and CeO 2 would increase the electrical conductivity, and the ZnFe 2O 4 based anodes with these additives were of good corrosion resistance. The current density on anode, the mole ratio of NaF/AlF 3 (MR) and the content of alumina in the bath effect the anode corrosion rate in different way.
文摘A New method,named atmospheric pressure plasma polishing,for the ultra-smooth machining of the silicon based materials is introduced.By inputting the CF4 gas into the atmospheric pressure plasma flame,high density reactive radicals will be generated,which will then react with the silicon based materials.The reaction product is the vaporization of the SiF4,which can be easily processed.In this way,the atomic scale material removal can be realized and the defect free ultra-smooth surface can be obtained.An experimental setup is built up,and the SiC polishing experiment is carried out.The AFM test result shows that the finished surface roughness (Ra) can be improved from 4.529 nm to 0.926 nm in 3 minutes.
文摘Material growth and device fabrication of the first 1.3μm quantum well (QW) edge emitting laser diodes in China are reported. Through the optimization of the molecular beam epitaxy (MBE) growth conditions and the tuning of the indium and nitrogen composition of the GalnNAs QWs, the emission wavelengths of the QWs can be tuned to 1.3μm. Ridge geometry waveguide laser diodes are fabricated. The lasing wavelength is 1.3μm under continuous current injection at room temperature with threshold current of 1kA/cm^2 for the laser diode structures with the cleaved facet mirrors. The output light power over 30mW is obtained.
文摘Poly (methyl methacrylate) is widely used as denture base material. During fabrication of a denture, the physical and mechanical properties are influenced by cure condition. Each cure cycle or fabrication technique is attempts to optimize the properties for a given application. The aim of this study was to compare two types of commercially available denture base materials (heat-cure and self-cure) in their mechanical properties. The samples were prepared according to the daily routine work for sample preparation in dental laboratories. After reaching dough stage the mix packed into dumbbell shaped of stainless steel mould and pressed in a hydraulic bench press for 25 mins at room temperature. For heat cure the polymerization cycle was carried out using water bath, while self cure was done at room temperature. The impact strength was evaluated using Charpy impact test. The hardness test was conducted using a calibrated Vickers hardness tester machine. The lowest impact strength was observed in self-cure denture base material (self cure material 6.2 kJ/m^2 while heat cure 12.69 kJ/m^2. It appears that the tendency of heat cure to fracture was lower than self-cure denture base materials. Heat cure denture base material has significantly higher hardness test values than self-cure denture base material. The observed VHN value of the heat-cure was 20.09 g/mm^2 while the self-cure value was 12.7 g/mm^2. This is may be due to the plasticizer effect of residual monomer which was higher in self curing material as reported in previous work. Generally, the heat cure material showed better properties compared to self cure material.
基金supported by the Ministry of Culture of the Czech Republic under the Research Projects NAKI DF11P01OVV028.
文摘Competitive absorption processes, i.e. condensation, of water and essential oils (EO) are predominantly controlled by extent of condensation of diffusing water and EO molecules with marginal influence of porose ligno-cellulosic matter and a sort of EO. With increase of absorption the diffusion is depressed and vice versa. Diffusion of water molecules through porose system is usually slower in comparison with other molecules. It was discovered that a presence of EO decreases paper web humidity with increasing influence in environment with high relative air humidity. Likely, fast diffusing EO molecules decrease the ability of water molecules condensed in all accessible pores particularly in the non-penetrable pores.
文摘Lithium ion battery (LIB) is one of the promising power storage devices in today’s world. Lithium ion battery like other types of electrochemical cell has anodic and cathodic electrode in which lithium ion is intercalated and deinterclated during charging and discharging process respectively. The capacity of lithium ion battery is improved by the development of innovative kinds of electrode. Carbon, metal/semiconductor, metal oxides and metal phosphides/ nitrides/sulfides based nanomaterials improve the capability of LIBs due to their high surface area, low diffusion distance, high electrical and ionic conductivity. Nanostructured materials represent a rapidly growing area in the field of Li-ion batteries because of their substantial advantages in terms of mass transport. In this review anode nanomaterials classified based on type of transition metal/semiconductor such as carbon, silicon, titanium and tin based nanomaterials are discussed. Additionally, different electrochemical reactions, comparative influence of anode materials on LIBs and their applications are widely explained.
基金Supported by the National Science and Technology (2006BAE03A11)the National Natural Science Foundation of China(50674062)
文摘The interaction of Si anions with Al sites during the hydration process was observed by NMR, IR and SEM to understand the reaction mechanism of the hydrates formation mixed with oil shale calcined at different temperatures. As the reaction progressed, the coordination of Al (Ⅳ, Ⅴ, and Ⅵ) changed almost completely to Ⅳ, when mixed with oil shale calcined at 700 ℃. However, when mixed with oil shale calcined at 400 ℃, some 6-coordination of Al still remained in the hydrates. Under the function of alkaline solutions, which were produced with the hydration of clinker, a certain amount of Si and Al atoms dissolved or hydrolyzed from aluminosilicate, formed geomonomers in solutions, and then polycondensed to form networks.
文摘Statement of problem: Many processes have been applied to improve the fracture resistance of acrylic resin dentures by reinforcing them. The maximum goal of any denture repair is to restore the main strength of the denture and to avoid further fracture. Purpose: This study investigated the ability of self-curing acrylic resin to be strength and deflection of repaired acrylic resin joints reinforced with various reinforcement materials to resist fracture. Material and methods: Transverse strength of polymethyl methacrylate acrylic resin reinforced with glass fiber mesh, metal mesh, and metal wire was evaluated with a 3-point load test on 40 intact specimens (n = 10 for control group) (n = 10 per each reinforcement material group). Fractured joint margins were rounded, a 4-mm gap was placed between them, and then they were repaired with autopolymerizing acrylic resin and retested. Results: Transverse strength for the polymethyl methacrylate acrylic resin samples has showed fracture at the side of sample rather than in the middle area of reinforcement materials and some other samples showed bending statue rather than fracture. Conclusion: Reinforcement with glass fiber mesh, metal mesh, and metal wire produced transverse strength in the side area of resin denture base material rather than in the middle of reinforcement area with bending samples rather than fracture response.
文摘The evolution of self organized Ge quantum dots structure is investigated by scanning tunneling microscopy and atomic force microscopy during annealing treatment up to 700℃ in an ultra high vacuum(UHV) system.When the sample temperature rises to 630℃,a great amount of new dots emerge on the wetting layer,which are believed to be incoherent islands compared with the dislocation free coherent islands formed during molecular beam epitaxy growth.
基金support from the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030006)National Natural Science Foundation of China(NSFC)(No.52071036)+1 种基金Key Research and Development Program of Zhejiang Province(No.2021C01086)the Fundamental Research Funds for the Central Universities Project(Nos.2021CDJCGJ009,SKLMT-ZZKT-2021M11)is also gratefully acknowledged.
文摘More than 4000 papers in the field of Mg and Mg alloys were published and indexed in Web of Science(WoS)Core Collection database in 2021.The bibliometric analyses indicate that the microstructure,mechanical properties,and corrosion of Mg alloys still are the main research focus.Mg ion batteries and hydrogen storage Mg materials have attracted much attention.Significant contributions to the research and development of magnesium alloys were made by Chongqing University,Shanghai Jiaotong University,and Chinese Academy of Sciences in China,Helmholtz Zentrum Hereon in Germany,Ohio State University in the United States,the University of Queensland in Australia,Kumanto University in Japan,and Seoul National University in Korea,University of Tehran in Iran,etc..This review is aimed to summarize the progress in the development of structural and functional Mg and Mg alloys in 2021.Based on the issues and challenges identified here,some future research directions are suggested.
文摘Hydrogenated amorphous silicon carbide (a-SixC1-x:H) films were grown on Si substrate by plasma-enhanced chemical vapor deposition. Fixed flow rate of H2 and different flow ratio of SiHJCH4 were used. Er-doped a-SixC1-x : H (a-SixC1-x-H :Er) films were prepared by implanting Er into the a- Si,C1-x-H host materials followed by annealing at different temperatures. The structure properties of the films were characterized by X-ray photoelectron spectroscopy (XPS), Raman spectra. infrared absorption Photoluminescence spectra (IR) and (PL) intensities depending on flow rates and annealing temperatures were studied. High annealing temperature is not favorable for PL because of C-surface segregation. It is shown that thermal quenching of this material is small by comparing the PL intensities of a-SixC1-x-H: Er at room temperature and low temperature.