Compared with sintered silicon carbides(SiC),highly-orientated 3C-SiC by CVD methods boast out-of-plane orientation uniformity,which ensures that such materials produce lower surface damage.Through the electrolytic in...Compared with sintered silicon carbides(SiC),highly-orientated 3C-SiC by CVD methods boast out-of-plane orientation uniformity,which ensures that such materials produce lower surface damage.Through the electrolytic in-process dressing(ELID)grinding technique,the differences in grinding behaviors between<110>and<111>-orientated 3C-SiC were investigated.Both highly-orientated 3C-SiC exhibited a grinding surface where brittle and ductile removal coexisted.Specifically,brittle removal regions were observed at grain boundaries,while ductile removal regions were observed within the grains.Further indentation experiments between the two 3C-SiC show that<111>-oriented 3C-SiC displays a larger critical cut depth of 28.99 nm,with 1.5 times higher than that of<110>-oriented 3C-SiC.The larger critical depth of cut contributes to more ductile removal regions with only a few brittle pits in the<111>-oriented 3C-SiC grinding surface.In addition,the subsurface deformation of<110>-oriented 3C-SiC was characterized by the presence of amorphous zones,dislocations and stacking faults.In contrast to the<111>-oriented,the<110>-oriented 3C-SiC tends to exhibit a brittle removal mode dominated by pits and cracks at the twin boundaries,as its pre-existing twins hinder the dislocation glide,resulting in stress concentration and thus forming cracks.展开更多
Laser etching and laser chemical vapor deposition(LCVD)techniques were proposed for the rapid preparation of high-purity,strongly bonded SiC porous micro-nano-coatings on quartz substrates.The laser serves as an exter...Laser etching and laser chemical vapor deposition(LCVD)techniques were proposed for the rapid preparation of high-purity,strongly bonded SiC porous micro-nano-coatings on quartz substrates.The laser serves as an external driving force for the vertical growth of SiC whiskers,facilitating the formation of a porous nanostructure that resembles coral models found in the macroscopic biological world.The porous nanostructures are beneficial for reducing thermal expansion mismatch and relieving residual stress.It is capable of eliminating the cracks on the surface of SiC coatings as well as enhancing the bonding of SiC coatings with quartz substrates to avoid coating detachment.展开更多
为评价不同生育时期早熟与晚熟燕麦(Avena sativa)的营养价值,本研究应用净碳水化合物−蛋白质体系(cornell net carbohydrate and protein system,CNCPS)对燕麦蛋白质和碳水化合物营养成分进行了细化测定,分析了燕麦各个生育时期各成分...为评价不同生育时期早熟与晚熟燕麦(Avena sativa)的营养价值,本研究应用净碳水化合物−蛋白质体系(cornell net carbohydrate and protein system,CNCPS)对燕麦蛋白质和碳水化合物营养成分进行了细化测定,分析了燕麦各个生育时期各成分的含量。处于灌浆期时两个品种的可利用蛋白比例最高,在开花期时结构性碳水化合物比例达到最大,但在灌浆期时可降解纤维含量最高。比较两个品种各生育时期的组分含量,发现晚熟燕麦中易降解蛋白质含量与早熟燕麦相比更为丰富,而不可降解蛋白质含量则较低,晚熟燕麦的可利用碳水化合物含量也要高于早熟燕麦。综上所述,两个品种燕麦在灌浆期时进行收获具有更高的利用价值,对于牧草饲喂及粗饲料的调制,晚熟燕麦的品质要优于早熟燕麦。展开更多
基金the Central Guidance on Local Science and Technology Development Fund of Hubei Province(No.2022BFE002)the Independent Innovation Projects of the Hubei Longzhong Laboratory(No.2022ZZ-06)the National Natural Science Foundation of China(Nos.52002075 and 62204179)。
文摘Compared with sintered silicon carbides(SiC),highly-orientated 3C-SiC by CVD methods boast out-of-plane orientation uniformity,which ensures that such materials produce lower surface damage.Through the electrolytic in-process dressing(ELID)grinding technique,the differences in grinding behaviors between<110>and<111>-orientated 3C-SiC were investigated.Both highly-orientated 3C-SiC exhibited a grinding surface where brittle and ductile removal coexisted.Specifically,brittle removal regions were observed at grain boundaries,while ductile removal regions were observed within the grains.Further indentation experiments between the two 3C-SiC show that<111>-oriented 3C-SiC displays a larger critical cut depth of 28.99 nm,with 1.5 times higher than that of<110>-oriented 3C-SiC.The larger critical depth of cut contributes to more ductile removal regions with only a few brittle pits in the<111>-oriented 3C-SiC grinding surface.In addition,the subsurface deformation of<110>-oriented 3C-SiC was characterized by the presence of amorphous zones,dislocations and stacking faults.In contrast to the<111>-oriented,the<110>-oriented 3C-SiC tends to exhibit a brittle removal mode dominated by pits and cracks at the twin boundaries,as its pre-existing twins hinder the dislocation glide,resulting in stress concentration and thus forming cracks.
基金Funded by the International Science&Technology Cooperation Program of Hubei Province of China(No.2022EHB024)the National Key Research and Development Plan(Nos.2018YFE0103600 and 2021YFB3703100)+1 种基金the National Natural Science Foundation of China(Nos.51872212,51972244,52002075,and 52102066)the 111 Project(No.B13035)。
文摘Laser etching and laser chemical vapor deposition(LCVD)techniques were proposed for the rapid preparation of high-purity,strongly bonded SiC porous micro-nano-coatings on quartz substrates.The laser serves as an external driving force for the vertical growth of SiC whiskers,facilitating the formation of a porous nanostructure that resembles coral models found in the macroscopic biological world.The porous nanostructures are beneficial for reducing thermal expansion mismatch and relieving residual stress.It is capable of eliminating the cracks on the surface of SiC coatings as well as enhancing the bonding of SiC coatings with quartz substrates to avoid coating detachment.
文摘为评价不同生育时期早熟与晚熟燕麦(Avena sativa)的营养价值,本研究应用净碳水化合物−蛋白质体系(cornell net carbohydrate and protein system,CNCPS)对燕麦蛋白质和碳水化合物营养成分进行了细化测定,分析了燕麦各个生育时期各成分的含量。处于灌浆期时两个品种的可利用蛋白比例最高,在开花期时结构性碳水化合物比例达到最大,但在灌浆期时可降解纤维含量最高。比较两个品种各生育时期的组分含量,发现晚熟燕麦中易降解蛋白质含量与早熟燕麦相比更为丰富,而不可降解蛋白质含量则较低,晚熟燕麦的可利用碳水化合物含量也要高于早熟燕麦。综上所述,两个品种燕麦在灌浆期时进行收获具有更高的利用价值,对于牧草饲喂及粗饲料的调制,晚熟燕麦的品质要优于早熟燕麦。
