The use of additive manufacturing techniques in the development of unconventional materials can help reduce the environmental impact of traditional construction materials.In this paper,the properties of a 3D-printed b...The use of additive manufacturing techniques in the development of unconventional materials can help reduce the environmental impact of traditional construction materials.In this paper,the properties of a 3D-printed biocomposite were evaluated.Biofilaments obtained by mixing pulverized bamboo fibers with polylactic acid(PLA)resin were extruded during the manufacturing process.To assess the effect of incorporating plant fibers,an analysis was conducted on the morphology,elemental chemical composition,crystallinity index,principal functional groups,thermal stability,surface roughness,microhardness,density,tensile strength,elastic modulus,and strain percentage of reinforced samples.The results were comparedwith those obtained from the characterization of standard PLAfilaments(unreinforced).The fused deposition modeling(FDM)technique was employed to print biocomposite specimens.Additionally,the influence of the printing parameters(infill density,build orientation,and layer thickness)on the physical,tribological,andmechanical properties of the biocomposites was analyzed.These results were compared with those obtained for specimens printed with pure PLA.The findings indicate that incorporating 10%vegetable filler into PLA filaments enhanced the strength and stiffness of the biocomposite under axial loads.Finally,the strength of the biocomposite subjected to axial loads was compared with the standardized values for wood-plastic composites,demonstrating the feasibility of its use for non-structural purposes in civil construction.展开更多
Transparent sand is a special material to realize visualization of concealed work in geotechnical engineering. To investigate the dynamic characteristics of transparent sand, a series of undrained cyclic simple shear ...Transparent sand is a special material to realize visualization of concealed work in geotechnical engineering. To investigate the dynamic characteristics of transparent sand, a series of undrained cyclic simple shear tests were conducted on the saturated transparent sand composed of fused quartz and refractive index-matched oil mixture. The results reveal that an increase in the initial shear stress ratio significantly affects the shape of the hysteresis loop, particularly resulting in more pronounced asymmetrical accumulation. Factors such as lower relative density, higher cyclic stress ratios and higher initial shear stress ratio have been shown to accelerate cyclic deformation, cyclic pore water pressure and stiffness degradation. The cyclic liquefaction resistance curves decrease as the initial shear stress ratio increases or as relative density decreases. Booker model and power law function model were applied to predict the pore water pressure for transparent sand. Both models yielded excellent fits for their respective condition, indicating a similar dynamic liquefaction pattern to that of natural sands. Finally, transparent sand displays similar dynamic characteristics in terms of cyclic liquefaction resistance and Kα correction factor. These comparisons indicate that transparent sand can serve as an effective means to mimic many natural sands in dynamic model tests.展开更多
Fused silica(SiO_(2)glass),a key amorphous component of Earth’s silicate minerals,undergoes coordination and phase transformations under high pressure.Although extensive studies have been conducted,discrepancies betw...Fused silica(SiO_(2)glass),a key amorphous component of Earth’s silicate minerals,undergoes coordination and phase transformations under high pressure.Although extensive studies have been conducted,discrepancies between theoretical and experimental studies remain,particularly regarding strain rate effects during compression.Here,we examine strain rate influences on the shock-induced amorphous–amorphous phase transitions in fused silica by measuring its Hugoniot equation of state and longitudinal sound velocity(CL)up to 7 GPa at strain rates of 10^(6)–10^(7)s^(-1)using a one-stage light-gas gun.A discontinuity in the relationship between shock velocity(US)and particle velocity(UP)and a significant softening in C_(L)of fused silica were observed near~5 GPa under shock loading.Our results indicate that high strain rates restrict Si–O–Si rotation in fused silica,modifying their bonds and increasing silicon coordination.The transition pressure by shock compression is significantly higher than that under static high-pressure conditions(2–3 GPa),which agrees with some recent theoretical predictions with high compression rates,reflecting the greater pressure needed to overcome energy barriers with the strain rate increase.These findings offer insights into strain rate-dependent phase transitions in fused silica and other silicate minerals(e.g.,quartz,olivine,and forsterite),bridging gaps between theoretical simulations and experiments.展开更多
Acrylonitrile–butadiene–styrene(ABS)is the main material used in fused deposition modeling(FDM),which has good toughness and strength,but the single ABS material has poor heat resistance,which tends to cause warping...Acrylonitrile–butadiene–styrene(ABS)is the main material used in fused deposition modeling(FDM),which has good toughness and strength,but the single ABS material has poor heat resistance,which tends to cause warping and deformation during the printing process.Polycarbonate(PC)exhibits good performance in heat resistance,allowing it to maintain stable performance at higher temperatures.In this work,PC was used as a blending modifier to prepare five kinds of ABS/PC composite filaments,and the mechanical and thermal properties of the ABS/PC(Acrylonitrile-butadiene-styrene/Polycarbonate)composite filaments were studied and analyzed.Results showed that the glass transition temperature(Tg)of the blend increased continuously as the PC content increased.When the mass fraction of ABS/PC was 50/50,the glass transition temperature of the blend increased by 21.21%,and the tensile strength of the composites reached 40.23 MPa,which was an increase of 36.47% compared with that of pure ABS.However,the impact strength of the composites decreased with the addition of PC.Moreover,with the increase in the mass fraction of PC,the printing accuracy error increased from 0.02 to 0.18 mm.The results of this paper will promote the improvement of ABS printing performance and enrich the available materials for FDM.展开更多
Fluorinated fused azobenzene boron(FBAz)is a novel electron-deficient building block for polymer electron acceptors in all-polymer solar cells(all-PSC).The B←N bridging units impart a fixed configuration and low-lyin...Fluorinated fused azobenzene boron(FBAz)is a novel electron-deficient building block for polymer electron acceptors in all-polymer solar cells(all-PSC).The B←N bridging units impart a fixed configuration and low-lying LUMO/HOMO energy.Three polymer acceptor materials(P2f,P3f and P5f)with different fluorine substitution positions by copolymerizing FBAz with indacenodithiophene(IDT),are synthesized and investigated to study the influence of fluorinated forms on the all-polymer solar cell performance.The FBAz units are synthesized in just three steps,facilitating the straightforward production of polymer acceptors P2f,P3f,and P5f.These acceptors exhibit strong light absorption in the visible to near-infrared range of 500-1000nm and possess suitable LUMO/HOMO energy levels of-3.99/-5.66 eV which are very complementary to that(E_(LUMO/HOMO)=-3.59/-5.20 eV)of the widely-used polymer donor poly[(ethylhexylthiophenyl)-benzodithiophene-(ethylhexyl)-thienothiophene](PTB7-Th).All-polymer solar cells(all-PSCs)with PTB7-Th as electron donor and P3f as electron acceptor exhibits highest power conversion efficiencies(PCE)2.70%.When PC_(61)BM is added as the third component,the device efficiency can reach 5.36%.These preliminary results indicate that FBAz is a promising strong electron acceptor for the development of n-type polymer semiconductors,especially in organic photovoltaics(OPVs).To the best of our knowledge,this is the first example demonstrating the unique photovoltaic properties of the N=N double bond as an acceptor material.展开更多
We demonstrate a new polarization smoothing(PS)approach utilizing residual stress birefringence in fused silica to create a spatially random polarization control plate(SRPCP),thereby improving target illumination unif...We demonstrate a new polarization smoothing(PS)approach utilizing residual stress birefringence in fused silica to create a spatially random polarization control plate(SRPCP),thereby improving target illumination uniformity in inertial confinement fusion(ICF)laser systems.The fundamental operating mechanism and key fabrication techniques for the SRPCP are systematically developed and experimentally validated.The SRPCP converts a linearly polarized 3ω incident laser beam into an output beam with a spatially randomized polarization distribution.When combined with a continuous phase plate,the SRPCP effectively suppresses high-intensity speckles at all spatial frequencies in the focal spot.The proposed PS technique is specifically designed for high-fluence large-aperture laser systems,enabling novel polarization control regimes in laser-driven ICF.展开更多
Additive manufacturing(AM),also known as 3D printing,is a process of creating three-dimensional objects with complex geometries that is utilized in various engineering applications.Continuous carbon fiber(CCF)is a hig...Additive manufacturing(AM),also known as 3D printing,is a process of creating three-dimensional objects with complex geometries that is utilized in various engineering applications.Continuous carbon fiber(CCF)is a high-performance material that offers a range of benefits in terms of strength,weight,and durability.Fused filament fabrication(FFF)is a type of AM that uses a thermoplastic filament as a material with which to create a three-dimensional object,and it has been widely used in various applications,as it enables the faster,cheaper,and more customizable production of parts and products.Lightweight cellular composite structures consists of small,repeating unit cells that are interconnected to form a larger structure,and they are employed in high engineering applications.In this study,cellular composite structures were fabricated using FFF technology,considering two types of infill paths design(grid and triangular)manufactured at three infill density levels(20%,40%,and 60%).After the fabrication process,tensile and flexural properties were experimentally investigated,and the influence of the infill pattern and density on the cellular composite parts were studied.The achieved results demonstrated that the infill design pattern and its density had great influence on the mechanical properties of the cellular structure.The obtained results also showed that the lightweight cellular composite parts had great potential for use in structural applications.展开更多
A numerical model based on measured fictive temperature distributions is explored to evaluate the residual stress fields of CO_(2)laser-annealed mitigated fused silica damage sites.The proposed model extracts the resi...A numerical model based on measured fictive temperature distributions is explored to evaluate the residual stress fields of CO_(2)laser-annealed mitigated fused silica damage sites.The proposed model extracts the residual strain from the differences in thermoelastic contraction of fused silica with different fictive temperatures from the initial frozen-in temperatures to ambient temperature.The residual stress fields of mitigated damage sites for the CO_(2)laser-annealed case are obtained by a finite element analysis of equilibrium equations and constitutive equations.The simulated results indicate that the proposed model can accurately evaluate the residual stress fields of laser-annealed mitigated damage sites with a complex thermal history.The calculated maximum hoop stress is in good agreement with the reported experimental result.The estimated optical retardance profiles from the calculated radial and hoop stress fields are consistent with the photoelastic measurements.These results provide sufficient evidence to demonstrate the suitability of the proposed model for describing the residual stresses of mitigated fused silica damage sites after CO_(2)laser annealing.展开更多
From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exh...From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exhibits several advantages in the regulation of energetic properties,the nonaromatic heterocycles,assembling nitramino explosophores with simple alkyl bridges,still have prevailed in benchmark materials.The methylene bridge plays a pivotal role in the constructions of the classic nonaromatic heterocycle-based energetic compounds,e.g.,hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX)and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),whereas ethylene bridge is the core moiety of state-of-the-art explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20).In this context,it is of great interest to employ simple and practical bridges to assemble aromatic and nonaromatic nitrogen-rich heterocycles,thereby expanding the structural diversity of energetic materials,e.g.,bridged and fused nitrogen-rich poly-heterocycles.Furthermore,alkyl-bridged poly-heterocycles highlight the potential for the open chain type of energetic materials.In this review,the development of alkyl bridges in linking nitrogen-rich heterocycles is presented,and the perspective of the newly constructed energetic backbones is summarized for the future design of advanced energetic materials.展开更多
Near-infrared(NIR)responsive compounds with narrow bandgaps play a crucial role in enhancing the photovoltaic efficiency of organic solar cells(OSCs)by effectively capturing high-energy NIR photons,as well as improvin...Near-infrared(NIR)responsive compounds with narrow bandgaps play a crucial role in enhancing the photovoltaic efficiency of organic solar cells(OSCs)by effectively capturing high-energy NIR photons,as well as improving the NIR sensitivity of organic photodetectors(OPDs)through NIR light detection[1,2].The design principle based on electron-donating and accepting(D−A)structures has led to the development of numerous A−D−A or A−DA’D−A type NIR responsive molecules,such as ITIC and Y6.展开更多
Para-quinols(p-quinols)are a kind of cyclohexa-2,5-dienones,and are widely used as active synthons in organic synthesis,medicinal chemistry and materials science.Herein,the efficient synthesis of poly-substituted aren...Para-quinols(p-quinols)are a kind of cyclohexa-2,5-dienones,and are widely used as active synthons in organic synthesis,medicinal chemistry and materials science.Herein,the efficient synthesis of poly-substituted arenes and fused cyclic compounds from p-quinols has been summarized.The mecha-nisms and the key driving force of these efficient transformations have been discussed.展开更多
In Fused Filament Fabrication(FFF),the state of material flow significantly influences printing outcomes.However,online monitoring of these micro-physical processes within the extruder remains challenging.The flow sta...In Fused Filament Fabrication(FFF),the state of material flow significantly influences printing outcomes.However,online monitoring of these micro-physical processes within the extruder remains challenging.The flow state is affected by multiple parameters,with temperature and volumetric flow rate(VFR)being the most critical.The study explores the stable extrusion of flow with a highly sensitive acoustic emission(AE)sensor so that AE signals generated by the friction in the annular region can reflect the flow state more effectively.Nevertheless,the large volume and broad frequency range of the data present processing challenges.This study proposes a method that initially selects short impact signals and then uses the Fast Kurtogram(FK)to identify the frequency with the highest kurtosis for signal filtration.The results indicate that this approach significantly enhances processing speed and improves feature extraction capabilities.By correlating AE characteristics under various parameters with the quality of extruded raster beads,AE can monitor the real-time state of material flow.This study offers a concise and efficient method for monitoring the state of raster beads and demonstrates the potential of online monitoring of the flow states.展开更多
Based on analyzing the influences of a slicing scheme on stair-stepping effect, supporting structure, efficiency and deformation, etc. , analytical hierarchical process （AHP） combining with fuzzy synthetic evaluatio...Based on analyzing the influences of a slicing scheme on stair-stepping effect, supporting structure, efficiency and deformation, etc. , analytical hierarchical process （AHP） combining with fuzzy synthetic evaluation is introduced to make decision in slicing schemes for a processing part. The application in determining the slicing scheme for a computer mouse during prototyping shows that the method increases the rationality during decision- making and improves quality and efficiency for the prototyping part.展开更多
In 2008,around 596 000 t of aluminum dross was generated from secondary aluminum industry in China;however,it was not sufficiently recycled yet.Approximately 95% of the Al dross was land filled without innocent treatm...In 2008,around 596 000 t of aluminum dross was generated from secondary aluminum industry in China;however,it was not sufficiently recycled yet.Approximately 95% of the Al dross was land filled without innocent treatment.The purpose of this work is to investigate Al dross recycling by environmentally efficient and friendly methods.Two methods of Al dross recycling which could utilize Al dross efficiently were presented.High-quality aluminum-silicon alloys and brown fused alumina(BFA) were produced successfully by recycling Al dross.Then,life cycle assessment(LCA) was performed to evaluate environmental impact of two methods of Al dross recycling process.The results show that the two methods are reasonable and the average recovery rate of Al dross is up to 98%.As the LCA results indicate,they have some advantages such as less natural resource consumption and pollutant emissions,which efficiently relieves the burden on the environment in electrolytic aluminum and secondary aluminum industry.展开更多
The existing research about ductile grinding of fused silica glass was mainly focused on how to carry out ductile regime material removal for generating very ＂smoothed＂ surface and investigate the machining-induced ...The existing research about ductile grinding of fused silica glass was mainly focused on how to carry out ductile regime material removal for generating very ＂smoothed＂ surface and investigate the machining-induced damage in the grinding in order to reduce or eliminate the subsurface damage.The brittle/ductile transition behavior of optical glass materials and the wear of diamond wheel are the most important factors for ductile grinding of optical glass.In this paper,the critical brittle/ductile depth,the influence factors on brittle/ductile transition behavior,the wear of diamond grits in diamond grinding of ultra pure fused silica（UPFS） are investigated by means of micro/nano indentation technique,as well as single grit diamond grinding on an ultra-stiff machine tool,Tetraform ＂C＂.The single grit grinding processes are in-process monitored using acoustic emission（AE） and force dynamometer simultaneously.The wear of diamond grits,morphology and subsurface integrity of the machined groves are examined with atomic force microscope（AFM） and scanning electron microscope（SEM）.The critical brittle/ductile depth of more than 0.5 μm is achieved.When compared to the using roof-like grits,by using pyramidal diamonds leads to higher critical depths of scratch with identical grinding parameters.However,the influence of grit shapes on the critical depth is not significant as supposed.The grinding force increased linearly with depth of cut in the ductile removal regime,but in brittle removal regime,there are large fluctuations instead of forces increase.The SEM photographs of the cross-section profile show that the median cracks dominate the crack patterns beneath the single grooves.Furthermore,The SEM photographs show multi worn patterns of diamond grits,indicating an inhomogeneous wear mechanism of diamond grits in grinding of fused silica with diamond grinding wheels.The proposed research provides the basal technical theory for improving the ultra-precision grinding of UPFS.展开更多
The densities of CO2 inclusions in minerals are commonly used to determine the crystallizing conditions of the host minerals. However, conventional microthermometry is difficult to apply for inclusions of small size ...The densities of CO2 inclusions in minerals are commonly used to determine the crystallizing conditions of the host minerals. However, conventional microthermometry is difficult to apply for inclusions of small size （〈 5-10 μm） or low density. Raman analysis is an alternative method for determining CO2 density, provided that the CO2 density-Raman shift relation is known. This study aims to establish this CO2 density-Raman shift relation by using CO2 inclusions synthesized in fused silica capillaries. By using this newly-developed synthetic technique, we formed pure CO2 inclusions, and their densities were determined by microthermometry. The Raman analysis showed that the relation between CO2 density （D in g/cm^3） and the separations （△ in cm^-1） between the two main bands （i.e. Fermi diad bands） in CO2 Raman spectra can be represented by a cubic equation： D （g/cm^3）=0.74203（-0.019^3＋5.90332△^2-610.79472△＋21050.30165）-3.54278 （r^2=0.99920）. Our calculated D value for a given A is between those obtained from two previously-reported equations, which were derived from different experimental methods. An example was given in this study to demonstrate that the densities of natural CO2 inclusions that could not be derived from microthermometry could be determined by using our method.展开更多
Rare earth gangue, which mainly consists of mixtures of light rare earths such as lanthana, ceria, neodymium oxide and praseodymium oxide, was used as the promoter of fused iron catalysts for ammonia synthesis. The re...Rare earth gangue, which mainly consists of mixtures of light rare earths such as lanthana, ceria, neodymium oxide and praseodymium oxide, was used as the promoter of fused iron catalysts for ammonia synthesis. The result showed that the activity of the catalyst promoted with rare earth gangue was comparable with those of commercial iron catalysts with high amount of cobalt. The role of rare earths was owed to their advantages for favoring the deep reduction of the main composite in catalyst, i.e., iron oxide. This fmding indicated that the use of rare earth gangue could decrease the content of cobalt or even completely replace cobalt, which was used to be regarded as unsub- stitutable promoters for high performance ammonia catalyst; therefore, the cost of fused iron catalysts would decrease significantly.展开更多
Inhomogeneity and low efficiency are two important factors that limit the application of laser-induced periodic surface structures(LIPSSs),especially on glass surfaces.In this study,two-beam interference(TBI)of femtos...Inhomogeneity and low efficiency are two important factors that limit the application of laser-induced periodic surface structures(LIPSSs),especially on glass surfaces.In this study,two-beam interference(TBI)of femtosecond lasers was used to produce large-area straight LIPSSs on fused silica using cylindrical lenses.Compared with those produced us-ing a single circular or cylindrical lens,the LIPSSs produced by TBI are much straighter and more regular.Depending on the laser fluence and scanning velocity,LIPSSs with grating-like or spaced LIPSSs are produced on the fused silica sur-face.Their structural colors are blue,green,and red,and only green and red,respectively.Grating-like LIPSS patterns oriented in different directions are obtained and exhibit bright and vivid colors,indicating potential applications in surface coloring and anti-counterfeiting logos.展开更多
基金a derivative product of the project INV-ING-3788 financed by the Vicerectory of Research of the Universidad Militar Nueva Granada,validity 2023.
文摘The use of additive manufacturing techniques in the development of unconventional materials can help reduce the environmental impact of traditional construction materials.In this paper,the properties of a 3D-printed biocomposite were evaluated.Biofilaments obtained by mixing pulverized bamboo fibers with polylactic acid(PLA)resin were extruded during the manufacturing process.To assess the effect of incorporating plant fibers,an analysis was conducted on the morphology,elemental chemical composition,crystallinity index,principal functional groups,thermal stability,surface roughness,microhardness,density,tensile strength,elastic modulus,and strain percentage of reinforced samples.The results were comparedwith those obtained from the characterization of standard PLAfilaments(unreinforced).The fused deposition modeling(FDM)technique was employed to print biocomposite specimens.Additionally,the influence of the printing parameters(infill density,build orientation,and layer thickness)on the physical,tribological,andmechanical properties of the biocomposites was analyzed.These results were compared with those obtained for specimens printed with pure PLA.The findings indicate that incorporating 10%vegetable filler into PLA filaments enhanced the strength and stiffness of the biocomposite under axial loads.Finally,the strength of the biocomposite subjected to axial loads was compared with the standardized values for wood-plastic composites,demonstrating the feasibility of its use for non-structural purposes in civil construction.
基金Project(U2268213) supported by the National Natural Science Foundation of ChinaProject(2024YFHZ0121) supported by the Sichuan Science and Technology Program,China。
文摘Transparent sand is a special material to realize visualization of concealed work in geotechnical engineering. To investigate the dynamic characteristics of transparent sand, a series of undrained cyclic simple shear tests were conducted on the saturated transparent sand composed of fused quartz and refractive index-matched oil mixture. The results reveal that an increase in the initial shear stress ratio significantly affects the shape of the hysteresis loop, particularly resulting in more pronounced asymmetrical accumulation. Factors such as lower relative density, higher cyclic stress ratios and higher initial shear stress ratio have been shown to accelerate cyclic deformation, cyclic pore water pressure and stiffness degradation. The cyclic liquefaction resistance curves decrease as the initial shear stress ratio increases or as relative density decreases. Booker model and power law function model were applied to predict the pore water pressure for transparent sand. Both models yielded excellent fits for their respective condition, indicating a similar dynamic liquefaction pattern to that of natural sands. Finally, transparent sand displays similar dynamic characteristics in terms of cyclic liquefaction resistance and Kα correction factor. These comparisons indicate that transparent sand can serve as an effective means to mimic many natural sands in dynamic model tests.
基金supported by the National Natural Science Foundation of China(Grant Nos.42422201,12175211,and 12350710177)the Sichuan Science and Technology Program(Grant No.2023NSFSC1910).
文摘Fused silica(SiO_(2)glass),a key amorphous component of Earth’s silicate minerals,undergoes coordination and phase transformations under high pressure.Although extensive studies have been conducted,discrepancies between theoretical and experimental studies remain,particularly regarding strain rate effects during compression.Here,we examine strain rate influences on the shock-induced amorphous–amorphous phase transitions in fused silica by measuring its Hugoniot equation of state and longitudinal sound velocity(CL)up to 7 GPa at strain rates of 10^(6)–10^(7)s^(-1)using a one-stage light-gas gun.A discontinuity in the relationship between shock velocity(US)and particle velocity(UP)and a significant softening in C_(L)of fused silica were observed near~5 GPa under shock loading.Our results indicate that high strain rates restrict Si–O–Si rotation in fused silica,modifying their bonds and increasing silicon coordination.The transition pressure by shock compression is significantly higher than that under static high-pressure conditions(2–3 GPa),which agrees with some recent theoretical predictions with high compression rates,reflecting the greater pressure needed to overcome energy barriers with the strain rate increase.These findings offer insights into strain rate-dependent phase transitions in fused silica and other silicate minerals(e.g.,quartz,olivine,and forsterite),bridging gaps between theoretical simulations and experiments.
基金the Natural Science Foundation of Shandong Province(grant no.ZR2020KF024)Yantai City Science and Technology Plan Project(grant no.2022ZDCX016)+1 种基金the University Research Project of Shandong Province(grant no.J17KB007)Natural Science Foundation of Shandong Jiaotong University(grant no.Z201937).
文摘Acrylonitrile–butadiene–styrene(ABS)is the main material used in fused deposition modeling(FDM),which has good toughness and strength,but the single ABS material has poor heat resistance,which tends to cause warping and deformation during the printing process.Polycarbonate(PC)exhibits good performance in heat resistance,allowing it to maintain stable performance at higher temperatures.In this work,PC was used as a blending modifier to prepare five kinds of ABS/PC composite filaments,and the mechanical and thermal properties of the ABS/PC(Acrylonitrile-butadiene-styrene/Polycarbonate)composite filaments were studied and analyzed.Results showed that the glass transition temperature(Tg)of the blend increased continuously as the PC content increased.When the mass fraction of ABS/PC was 50/50,the glass transition temperature of the blend increased by 21.21%,and the tensile strength of the composites reached 40.23 MPa,which was an increase of 36.47% compared with that of pure ABS.However,the impact strength of the composites decreased with the addition of PC.Moreover,with the increase in the mass fraction of PC,the printing accuracy error increased from 0.02 to 0.18 mm.The results of this paper will promote the improvement of ABS printing performance and enrich the available materials for FDM.
基金supported by the National Natural Science Foundation of China(No.22375123)the Shuguang Program of Shanghai Education Development Foundation,the Shanxi-Zheda Institute of Advanced Materials and Chemical Engineering(No.2022SXTD012)。
文摘Fluorinated fused azobenzene boron(FBAz)is a novel electron-deficient building block for polymer electron acceptors in all-polymer solar cells(all-PSC).The B←N bridging units impart a fixed configuration and low-lying LUMO/HOMO energy.Three polymer acceptor materials(P2f,P3f and P5f)with different fluorine substitution positions by copolymerizing FBAz with indacenodithiophene(IDT),are synthesized and investigated to study the influence of fluorinated forms on the all-polymer solar cell performance.The FBAz units are synthesized in just three steps,facilitating the straightforward production of polymer acceptors P2f,P3f,and P5f.These acceptors exhibit strong light absorption in the visible to near-infrared range of 500-1000nm and possess suitable LUMO/HOMO energy levels of-3.99/-5.66 eV which are very complementary to that(E_(LUMO/HOMO)=-3.59/-5.20 eV)of the widely-used polymer donor poly[(ethylhexylthiophenyl)-benzodithiophene-(ethylhexyl)-thienothiophene](PTB7-Th).All-polymer solar cells(all-PSCs)with PTB7-Th as electron donor and P3f as electron acceptor exhibits highest power conversion efficiencies(PCE)2.70%.When PC_(61)BM is added as the third component,the device efficiency can reach 5.36%.These preliminary results indicate that FBAz is a promising strong electron acceptor for the development of n-type polymer semiconductors,especially in organic photovoltaics(OPVs).To the best of our knowledge,this is the first example demonstrating the unique photovoltaic properties of the N=N double bond as an acceptor material.
基金supported by the National Natural Science Foundation of China(Grant No.62275235).
文摘We demonstrate a new polarization smoothing(PS)approach utilizing residual stress birefringence in fused silica to create a spatially random polarization control plate(SRPCP),thereby improving target illumination uniformity in inertial confinement fusion(ICF)laser systems.The fundamental operating mechanism and key fabrication techniques for the SRPCP are systematically developed and experimentally validated.The SRPCP converts a linearly polarized 3ω incident laser beam into an output beam with a spatially randomized polarization distribution.When combined with a continuous phase plate,the SRPCP effectively suppresses high-intensity speckles at all spatial frequencies in the focal spot.The proposed PS technique is specifically designed for high-fluence large-aperture laser systems,enabling novel polarization control regimes in laser-driven ICF.
文摘Additive manufacturing(AM),also known as 3D printing,is a process of creating three-dimensional objects with complex geometries that is utilized in various engineering applications.Continuous carbon fiber(CCF)is a high-performance material that offers a range of benefits in terms of strength,weight,and durability.Fused filament fabrication(FFF)is a type of AM that uses a thermoplastic filament as a material with which to create a three-dimensional object,and it has been widely used in various applications,as it enables the faster,cheaper,and more customizable production of parts and products.Lightweight cellular composite structures consists of small,repeating unit cells that are interconnected to form a larger structure,and they are employed in high engineering applications.In this study,cellular composite structures were fabricated using FFF technology,considering two types of infill paths design(grid and triangular)manufactured at three infill density levels(20%,40%,and 60%).After the fabrication process,tensile and flexural properties were experimentally investigated,and the influence of the infill pattern and density on the cellular composite parts were studied.The achieved results demonstrated that the infill design pattern and its density had great influence on the mechanical properties of the cellular structure.The obtained results also showed that the lightweight cellular composite parts had great potential for use in structural applications.
基金Project supported by the National Natural Science Foundation of China(Grant No.62275235).
文摘A numerical model based on measured fictive temperature distributions is explored to evaluate the residual stress fields of CO_(2)laser-annealed mitigated fused silica damage sites.The proposed model extracts the residual strain from the differences in thermoelastic contraction of fused silica with different fictive temperatures from the initial frozen-in temperatures to ambient temperature.The residual stress fields of mitigated damage sites for the CO_(2)laser-annealed case are obtained by a finite element analysis of equilibrium equations and constitutive equations.The simulated results indicate that the proposed model can accurately evaluate the residual stress fields of laser-annealed mitigated damage sites with a complex thermal history.The calculated maximum hoop stress is in good agreement with the reported experimental result.The estimated optical retardance profiles from the calculated radial and hoop stress fields are consistent with the photoelastic measurements.These results provide sufficient evidence to demonstrate the suitability of the proposed model for describing the residual stresses of mitigated fused silica damage sites after CO_(2)laser annealing.
基金National Natural Science Foundation of China(Grant Nos.22075023,22205022,and 22235003)to provide fund for conducting experiments。
文摘From the standpoint of chemical structures,the organic backbones of energetic materials can be classified into aromatic rings,nonaromatic rings,and open chains.Although the category of aromatic energetic compounds exhibits several advantages in the regulation of energetic properties,the nonaromatic heterocycles,assembling nitramino explosophores with simple alkyl bridges,still have prevailed in benchmark materials.The methylene bridge plays a pivotal role in the constructions of the classic nonaromatic heterocycle-based energetic compounds,e.g.,hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX)and octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),whereas ethylene bridge is the core moiety of state-of-the-art explosive 2,4,6,8,10,12-hexanitro-2,4,6,8,10,12-hexaazaisowurtzitane(CL-20).In this context,it is of great interest to employ simple and practical bridges to assemble aromatic and nonaromatic nitrogen-rich heterocycles,thereby expanding the structural diversity of energetic materials,e.g.,bridged and fused nitrogen-rich poly-heterocycles.Furthermore,alkyl-bridged poly-heterocycles highlight the potential for the open chain type of energetic materials.In this review,the development of alkyl bridges in linking nitrogen-rich heterocycles is presented,and the perspective of the newly constructed energetic backbones is summarized for the future design of advanced energetic materials.
基金supported by the National Natural Science Foundation of China (52263019)the Yunnan Fundamental Research Projects (202301AT070313).
文摘Near-infrared(NIR)responsive compounds with narrow bandgaps play a crucial role in enhancing the photovoltaic efficiency of organic solar cells(OSCs)by effectively capturing high-energy NIR photons,as well as improving the NIR sensitivity of organic photodetectors(OPDs)through NIR light detection[1,2].The design principle based on electron-donating and accepting(D−A)structures has led to the development of numerous A−D−A or A−DA’D−A type NIR responsive molecules,such as ITIC and Y6.
基金supported by the Department of Science and Technology of Jilin Province(20220402046GH,20220101066JC).
文摘Para-quinols(p-quinols)are a kind of cyclohexa-2,5-dienones,and are widely used as active synthons in organic synthesis,medicinal chemistry and materials science.Herein,the efficient synthesis of poly-substituted arenes and fused cyclic compounds from p-quinols has been summarized.The mecha-nisms and the key driving force of these efficient transformations have been discussed.
文摘In Fused Filament Fabrication(FFF),the state of material flow significantly influences printing outcomes.However,online monitoring of these micro-physical processes within the extruder remains challenging.The flow state is affected by multiple parameters,with temperature and volumetric flow rate(VFR)being the most critical.The study explores the stable extrusion of flow with a highly sensitive acoustic emission(AE)sensor so that AE signals generated by the friction in the annular region can reflect the flow state more effectively.Nevertheless,the large volume and broad frequency range of the data present processing challenges.This study proposes a method that initially selects short impact signals and then uses the Fast Kurtogram(FK)to identify the frequency with the highest kurtosis for signal filtration.The results indicate that this approach significantly enhances processing speed and improves feature extraction capabilities.By correlating AE characteristics under various parameters with the quality of extruded raster beads,AE can monitor the real-time state of material flow.This study offers a concise and efficient method for monitoring the state of raster beads and demonstrates the potential of online monitoring of the flow states.
基金Supported by the Science and Technology Support Key Project of Jiangsu Province (DE2008365)~~
文摘Based on analyzing the influences of a slicing scheme on stair-stepping effect, supporting structure, efficiency and deformation, etc. , analytical hierarchical process （AHP） combining with fuzzy synthetic evaluation is introduced to make decision in slicing schemes for a processing part. The application in determining the slicing scheme for a computer mouse during prototyping shows that the method increases the rationality during decision- making and improves quality and efficiency for the prototyping part.
基金Project(07dz12028) supported by the Science Program of Science and Technology Commission of Shanghai Municipality,China
文摘In 2008,around 596 000 t of aluminum dross was generated from secondary aluminum industry in China;however,it was not sufficiently recycled yet.Approximately 95% of the Al dross was land filled without innocent treatment.The purpose of this work is to investigate Al dross recycling by environmentally efficient and friendly methods.Two methods of Al dross recycling which could utilize Al dross efficiently were presented.High-quality aluminum-silicon alloys and brown fused alumina(BFA) were produced successfully by recycling Al dross.Then,life cycle assessment(LCA) was performed to evaluate environmental impact of two methods of Al dross recycling process.The results show that the two methods are reasonable and the average recovery rate of Al dross is up to 98%.As the LCA results indicate,they have some advantages such as less natural resource consumption and pollutant emissions,which efficiently relieves the burden on the environment in electrolytic aluminum and secondary aluminum industry.
基金supported by National Key Science and Technology Projects of China (Grant No. 2009ZX04001-101, Grant No. 2009ZX01001-151)New Century Excellent Talents in University,China (GrantNo. NCET-07-0246)National Natural Science Foundation of China(Grant No. 50675051)
文摘The existing research about ductile grinding of fused silica glass was mainly focused on how to carry out ductile regime material removal for generating very ＂smoothed＂ surface and investigate the machining-induced damage in the grinding in order to reduce or eliminate the subsurface damage.The brittle/ductile transition behavior of optical glass materials and the wear of diamond wheel are the most important factors for ductile grinding of optical glass.In this paper,the critical brittle/ductile depth,the influence factors on brittle/ductile transition behavior,the wear of diamond grits in diamond grinding of ultra pure fused silica（UPFS） are investigated by means of micro/nano indentation technique,as well as single grit diamond grinding on an ultra-stiff machine tool,Tetraform ＂C＂.The single grit grinding processes are in-process monitored using acoustic emission（AE） and force dynamometer simultaneously.The wear of diamond grits,morphology and subsurface integrity of the machined groves are examined with atomic force microscope（AFM） and scanning electron microscope（SEM）.The critical brittle/ductile depth of more than 0.5 μm is achieved.When compared to the using roof-like grits,by using pyramidal diamonds leads to higher critical depths of scratch with identical grinding parameters.However,the influence of grit shapes on the critical depth is not significant as supposed.The grinding force increased linearly with depth of cut in the ductile removal regime,but in brittle removal regime,there are large fluctuations instead of forces increase.The SEM photographs of the cross-section profile show that the median cracks dominate the crack patterns beneath the single grooves.Furthermore,The SEM photographs show multi worn patterns of diamond grits,indicating an inhomogeneous wear mechanism of diamond grits in grinding of fused silica with diamond grinding wheels.The proposed research provides the basal technical theory for improving the ultra-precision grinding of UPFS.
基金funded by Basic Outlay of Scientific Research Work from the Ministry of Science and Technology of China *J0723 to Song Yucai)China Postdoctoral Science Foundation(20070420418 to Song Yucai)National Natural Science Foundation of China (40673040 to Hu Wenxuan),and Energy Program of the USGS(to Chou I-Ming)
文摘The densities of CO2 inclusions in minerals are commonly used to determine the crystallizing conditions of the host minerals. However, conventional microthermometry is difficult to apply for inclusions of small size （〈 5-10 μm） or low density. Raman analysis is an alternative method for determining CO2 density, provided that the CO2 density-Raman shift relation is known. This study aims to establish this CO2 density-Raman shift relation by using CO2 inclusions synthesized in fused silica capillaries. By using this newly-developed synthetic technique, we formed pure CO2 inclusions, and their densities were determined by microthermometry. The Raman analysis showed that the relation between CO2 density （D in g/cm^3） and the separations （△ in cm^-1） between the two main bands （i.e. Fermi diad bands） in CO2 Raman spectra can be represented by a cubic equation： D （g/cm^3）=0.74203（-0.019^3＋5.90332△^2-610.79472△＋21050.30165）-3.54278 （r^2=0.99920）. Our calculated D value for a given A is between those obtained from two previously-reported equations, which were derived from different experimental methods. An example was given in this study to demonstrate that the densities of natural CO2 inclusions that could not be derived from microthermometry could be determined by using our method.
基金the National Natural Science Foundation of China (20576021)Science & Technology Priority Project of Fujian Province (2005HZ01-2)National Key Technology R&D Program of China (2007BAE08B02)
文摘Rare earth gangue, which mainly consists of mixtures of light rare earths such as lanthana, ceria, neodymium oxide and praseodymium oxide, was used as the promoter of fused iron catalysts for ammonia synthesis. The result showed that the activity of the catalyst promoted with rare earth gangue was comparable with those of commercial iron catalysts with high amount of cobalt. The role of rare earths was owed to their advantages for favoring the deep reduction of the main composite in catalyst, i.e., iron oxide. This fmding indicated that the use of rare earth gangue could decrease the content of cobalt or even completely replace cobalt, which was used to be regarded as unsub- stitutable promoters for high performance ammonia catalyst; therefore, the cost of fused iron catalysts would decrease significantly.
文摘Inhomogeneity and low efficiency are two important factors that limit the application of laser-induced periodic surface structures(LIPSSs),especially on glass surfaces.In this study,two-beam interference(TBI)of femtosecond lasers was used to produce large-area straight LIPSSs on fused silica using cylindrical lenses.Compared with those produced us-ing a single circular or cylindrical lens,the LIPSSs produced by TBI are much straighter and more regular.Depending on the laser fluence and scanning velocity,LIPSSs with grating-like or spaced LIPSSs are produced on the fused silica sur-face.Their structural colors are blue,green,and red,and only green and red,respectively.Grating-like LIPSS patterns oriented in different directions are obtained and exhibit bright and vivid colors,indicating potential applications in surface coloring and anti-counterfeiting logos.
