In practical engineering applications,rock mass are often found to be subjected to a triaxial stress state.Concurrently,defects like joints and fractures have a notable impact on the mechanical behavior of rock mass.S...In practical engineering applications,rock mass are often found to be subjected to a triaxial stress state.Concurrently,defects like joints and fractures have a notable impact on the mechanical behavior of rock mass.Such defects are identified as crucial contributors to the failure and instability of the surrounding rock,subsequently impacting the engineering stability.The study aimed to investigate the impact of fracture geometry and confining pressure on the deformation,failure characteristics,and strength of specimens using sand powder 3D printing technology and conventional triaxial compression tests.The results indicate that the number of fractures present considerably influences the peak strength,axial peak strain and elastic modulus of the specimens.Confining pressure is an important factor affecting the failure pattern of the specimen,under which the specimen is more prone to shear failure,but the initiation,expansion and penetration processes of secondary cracks in different fracture specimens are different.This study confirmed the feasibility of using sand powder 3D printing specimens as soft rock analogs for triaxial compression research.The insights from this research are deemed essential for a deeper understanding of the mechanical behavior of fractured surrounding rocks when under triaxial stress state.展开更多
The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi（NO3）3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffr...The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi（NO3）3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffraction and transmission electron microscopy, respectively. The results show that under the optimum condition that 300g/L Bi（NO3）3 reacts at 90℃ for 2h, the Bi2O3 powders with 60nm on the average and 99.5% in purity are obtained. The prepared nano-Bi2O3 powders contain a mixed crystal structure of monoclinic and triclinic instead of traditional structure of monoclinic α-Bi2O3. And the mixed crystal structure is stable in air. The reason for the appearance of the mixed crystal structure may be that the ionic radius ratio of Bi 3+ to O 2- changes easily during the formation of nano-Bi2O3 particles by a chemical precipitation method.展开更多
Ultrafine alumina power was obtained by calcining the precursor at 1 200 ℃ for 2 h, which was prepared by homogeneous precipitation method using aluminium salts and urea as raw materials. The effects of anions on the...Ultrafine alumina power was obtained by calcining the precursor at 1 200 ℃ for 2 h, which was prepared by homogeneous precipitation method using aluminium salts and urea as raw materials. The effects of anions on the morphology, particle size, surface area and configuration of the precursors were studied. The results show that the reactions of urea with aluminium nitrate and aluminium chloride result in agglomerates gels with bad filtering performance, the morphology is fibrillar. Aluminium sulphate-urea reactions result in the direct formation of amorphous powders with good filtering performance, of which morphology are regular spherical particles with larger granularity and smaller surface area. The reaction of mutual compound of aluminium sulphate and aluminium nitrate with molar ratio of 40:60 with urea can produce precursor with good filtering performance, spherical morphology, and uniform granularity distribution in the particle size range of 2-3 μm.展开更多
OBJECTIVE The Ginkgo Leaf Extract and Armillariella Mellea Powders Oral(Yinxingmihuan Koufu Rongye,YXMH),a representative drug for"Treating both Brain and Heart",showed considerable clinical effects in isch⁃...OBJECTIVE The Ginkgo Leaf Extract and Armillariella Mellea Powders Oral(Yinxingmihuan Koufu Rongye,YXMH),a representative drug for"Treating both Brain and Heart",showed considerable clinical effects in isch⁃emic cardiovascular and cerebral vascular diseases.Recently,it is reported that YXMH has the potential for treating myocardial and cerebral ischemia related mental disorders,such as post stroke depression(PSD)and chronic heart disease(CHD)associated anxiety disorder.However,its mechanism has not been clearly elucidated.Meanwhile,increasing evidence revealed that there are close functional links between depression and habenular nucleus.The present study investigates the underlying mechanism of YXMH on attenuating the inflammation of microglia in habenular nucleus through CX3CL1-CX3CR1 axis in in a rat model of PSD.METHODS Rats were randomly devided into sham group,model group,Ginaton group(18 mg·kg^-1),Armillariella Mellea group(600 mg·kg-1),Fluoxetine group(10 mg·kg^-1),YXMH high-dose group(618 mg·kg^-1)and YXMH low-dose group(309 mg·kg^-1).The PSD model was induced by transarterial microembolization combined with sleep deprivation(2-Chloro-D-phenylalanine,PCPA,IH,200 mg·kg^-1,for 3 times,before the behavior test)in SD male rats.Then rats were treated with corresponding medicaments through gavage once a day until 3 weeks later,followed by body mass measurement,neurological deficit score evaluation,gripping strength and thermal withdrawl latency measurement,as well as depression related behavioral indicators,the open field test(OFT)and sucrose preference test.The pathological morphological changes of habenular nucleus was observed by HE staining,the expression of IBA-1 was measured and analyzed by immunohistochemistry staining,and alterations of proteins and genes related to the CX3CL1-CX3CR1 axis were analyzed using Western blotting(CX3CL1,CX3CR1)and real-time polymerase chain reaction(PCR)(CX3CL1,CX3CR1).RESULTS Compared with the sham group,rats in the model group manifested as decreased body mass,deficient neurological behavior and gripping strength,reduced loco⁃motor activity and sugar water consumption,as well as elevated thermal withdrawl latency(P<0.05,P<0.01).Mean⁃while,the pathological morphology of the habenular nucleus on the ischemic hemisphere showed significant neuronal degeneration,microglial proliferation,inflammatory cells and glia cells infiltration,together with up-regualted expression of IBA-1,CX3CL1,CX3CR1 protein and CX3CL1,CX3CR1 mRNA.YXMH attenuated inflammation of microglia in habenular nucleus through improving pathological morphology,inhibiting IBA-1 activation,down-regulating the expres⁃sion of CX3CL1 and CX3CR1 proteins and genes,and thus improved the behavior performance of ischemic injury and depression.CONCLUSION YXMH ameliorates neurological deficit and depressive behavior in rat model of PSD induced by transarterial microembolization combined with sleep deprivation,and the mechanism is probably related to attenu⁃ating inflammation of microglia in habenular nucleus through CX3CL1-CX3CR1 axis.展开更多
基金Project(2021YFC2900600)supported by the Young Scientist Project of National Key Research and Development Program of ChinaProject(52074166)supported by the National Natural Science Foundation of China+1 种基金Projects(ZR2021YQ38,ZR2020QE121)supported by the Natural Science Foundation of Shandong Province,ChinaProject(2022KJ101)supported by the Science and Technology Support Plan for Youth Innovation of Colleges and Universities in Shandong Province,China。
文摘In practical engineering applications,rock mass are often found to be subjected to a triaxial stress state.Concurrently,defects like joints and fractures have a notable impact on the mechanical behavior of rock mass.Such defects are identified as crucial contributors to the failure and instability of the surrounding rock,subsequently impacting the engineering stability.The study aimed to investigate the impact of fracture geometry and confining pressure on the deformation,failure characteristics,and strength of specimens using sand powder 3D printing technology and conventional triaxial compression tests.The results indicate that the number of fractures present considerably influences the peak strength,axial peak strain and elastic modulus of the specimens.Confining pressure is an important factor affecting the failure pattern of the specimen,under which the specimen is more prone to shear failure,but the initiation,expansion and penetration processes of secondary cracks in different fracture specimens are different.This study confirmed the feasibility of using sand powder 3D printing specimens as soft rock analogs for triaxial compression research.The insights from this research are deemed essential for a deeper understanding of the mechanical behavior of fractured surrounding rocks when under triaxial stress state.
文摘The nano-Bi2O3 powders were prepared by a chemical precipitation method with Bi（NO3）3, HNO3 and NaOH as reactants. The structural characteristics and morphology of nano-Bi2O3 powders were investigated by X-ray diffraction and transmission electron microscopy, respectively. The results show that under the optimum condition that 300g/L Bi（NO3）3 reacts at 90℃ for 2h, the Bi2O3 powders with 60nm on the average and 99.5% in purity are obtained. The prepared nano-Bi2O3 powders contain a mixed crystal structure of monoclinic and triclinic instead of traditional structure of monoclinic α-Bi2O3. And the mixed crystal structure is stable in air. The reason for the appearance of the mixed crystal structure may be that the ionic radius ratio of Bi 3+ to O 2- changes easily during the formation of nano-Bi2O3 particles by a chemical precipitation method.
基金Project(5JJ3010) supported by the Natural Science Foundation of Hunan Province, China
文摘Ultrafine alumina power was obtained by calcining the precursor at 1 200 ℃ for 2 h, which was prepared by homogeneous precipitation method using aluminium salts and urea as raw materials. The effects of anions on the morphology, particle size, surface area and configuration of the precursors were studied. The results show that the reactions of urea with aluminium nitrate and aluminium chloride result in agglomerates gels with bad filtering performance, the morphology is fibrillar. Aluminium sulphate-urea reactions result in the direct formation of amorphous powders with good filtering performance, of which morphology are regular spherical particles with larger granularity and smaller surface area. The reaction of mutual compound of aluminium sulphate and aluminium nitrate with molar ratio of 40:60 with urea can produce precursor with good filtering performance, spherical morphology, and uniform granularity distribution in the particle size range of 2-3 μm.
基金National Natural Science Foundation of China(8187304081403141)
文摘OBJECTIVE The Ginkgo Leaf Extract and Armillariella Mellea Powders Oral(Yinxingmihuan Koufu Rongye,YXMH),a representative drug for"Treating both Brain and Heart",showed considerable clinical effects in isch⁃emic cardiovascular and cerebral vascular diseases.Recently,it is reported that YXMH has the potential for treating myocardial and cerebral ischemia related mental disorders,such as post stroke depression(PSD)and chronic heart disease(CHD)associated anxiety disorder.However,its mechanism has not been clearly elucidated.Meanwhile,increasing evidence revealed that there are close functional links between depression and habenular nucleus.The present study investigates the underlying mechanism of YXMH on attenuating the inflammation of microglia in habenular nucleus through CX3CL1-CX3CR1 axis in in a rat model of PSD.METHODS Rats were randomly devided into sham group,model group,Ginaton group(18 mg·kg^-1),Armillariella Mellea group(600 mg·kg-1),Fluoxetine group(10 mg·kg^-1),YXMH high-dose group(618 mg·kg^-1)and YXMH low-dose group(309 mg·kg^-1).The PSD model was induced by transarterial microembolization combined with sleep deprivation(2-Chloro-D-phenylalanine,PCPA,IH,200 mg·kg^-1,for 3 times,before the behavior test)in SD male rats.Then rats were treated with corresponding medicaments through gavage once a day until 3 weeks later,followed by body mass measurement,neurological deficit score evaluation,gripping strength and thermal withdrawl latency measurement,as well as depression related behavioral indicators,the open field test(OFT)and sucrose preference test.The pathological morphological changes of habenular nucleus was observed by HE staining,the expression of IBA-1 was measured and analyzed by immunohistochemistry staining,and alterations of proteins and genes related to the CX3CL1-CX3CR1 axis were analyzed using Western blotting(CX3CL1,CX3CR1)and real-time polymerase chain reaction(PCR)(CX3CL1,CX3CR1).RESULTS Compared with the sham group,rats in the model group manifested as decreased body mass,deficient neurological behavior and gripping strength,reduced loco⁃motor activity and sugar water consumption,as well as elevated thermal withdrawl latency(P<0.05,P<0.01).Mean⁃while,the pathological morphology of the habenular nucleus on the ischemic hemisphere showed significant neuronal degeneration,microglial proliferation,inflammatory cells and glia cells infiltration,together with up-regualted expression of IBA-1,CX3CL1,CX3CR1 protein and CX3CL1,CX3CR1 mRNA.YXMH attenuated inflammation of microglia in habenular nucleus through improving pathological morphology,inhibiting IBA-1 activation,down-regulating the expres⁃sion of CX3CL1 and CX3CR1 proteins and genes,and thus improved the behavior performance of ischemic injury and depression.CONCLUSION YXMH ameliorates neurological deficit and depressive behavior in rat model of PSD induced by transarterial microembolization combined with sleep deprivation,and the mechanism is probably related to attenu⁃ating inflammation of microglia in habenular nucleus through CX3CL1-CX3CR1 axis.
