The thermal-induced error is a very important sour ce of machining errors of machine tools. To compensate the thermal-induced machin ing errors, a relationship model between the thermal field and deformations was need...The thermal-induced error is a very important sour ce of machining errors of machine tools. To compensate the thermal-induced machin ing errors, a relationship model between the thermal field and deformations was needed. The relationship can be deduced by virtual of FEM (Finite Element Method ), ANN (Artificial Neural Network) or MRA (Multiple Regression Analysis). MR A is on the basis of a total understanding of the temperature distribution of th e machine tool. Although the more the temperatures measured are, the more accura te the MRA is, too more temperatures will hinder the analysis calculation. So it is necessary to identify the key temperatures of the machine tool. The selectio n of key temperatures decides the efficiency and precision of MRA. Because of th e complexities and multi-input and multi-output structure of the relationships , the exact quantitative portions as well as the unclear portions must be taken into consideration together to improve the identification of key temperatures. I n this paper, a fuzzy cluster analysis was used to select the key temperatures. The substance of identifying the key temperatures is to group all temperatures b y their relativity, and then to select a temperature from each group as the repr esentation. A fuzzy cluster analysis can uncover the relationships between t he thermal field and deformations more truly and thoroughly. A fuzzy cluster ana lysis is the cluster analysis based on fuzzy sets. Given U={u i|i=0,...,N}, in which u i is the temperature measured, a fuzzy matrix R can be obta ined. The transfer close package t(R) can be deduced from R. A fuzzy clu ster of U then conducts on the basis of t(R). Based on the fuzzy cluster analysis discussed above, this paper identified the k ey temperatures of a horizontal machining center. The number of the temperatures measured was reduced to 4 from 32, and then the multiple regression relationshi p models between the 4 temperatures and the thermal deformations of the spindle were drawn. The remnant errors between the regression models and measured deform ations reached a satisfying low level. At the same time, the decreasing of tempe rature variable number improved the efficiency of measure and analysis greatly.展开更多
Introduction There are big disputes on the uplift of the Tibetan Plateau. Some scientists believe the plateau uplifted to its highest elevation by 14Ma BP,and it decreased in elevation afterward. The second idea about...Introduction There are big disputes on the uplift of the Tibetan Plateau. Some scientists believe the plateau uplifted to its highest elevation by 14Ma BP,and it decreased in elevation afterward. The second idea about the uplift of the plateau was similar to the first one in tectonic theory, but they consider the time of C3 plant change to C4 in the South Asia, as the time when the plateau reached its highest elevation. This time is 8Ma BP. The third idea, the most Chinese scientists believed, the nearest uplift of the plateau took place since 3 4Ma BP. The occurrence of fault depression and gravel deposit with large thickness in the inner and the marge of the plateau represented the speed uplift. After the collision of the India plate and the Eurasia plateau by the 36Ma, the Tibetean area uplifted several times, but it had been planed to lower area. The plateau with 4500m elevation formed in the Quaternary. While our recent research in the Kunlun Pass area suggest , the nearest uplift occurred at the border of the Early and Middle Pleistocene, and before that time, the elevation of this area was no more than 1500 m.展开更多
Objective:Osteoarthritis(OA)and sarcopenia are significant health concerns in the elderly,substantially impacting their daily activities and quality of life.However,the relationship between them remains poorly underst...Objective:Osteoarthritis(OA)and sarcopenia are significant health concerns in the elderly,substantially impacting their daily activities and quality of life.However,the relationship between them remains poorly understood.This study aims to uncover common biomarkers and pathways associated with both OA and sarcopenia.Methods:Gene expression profiles related to OA and sarcopenia were retrieved from the Gene Expression Omnibus(GEO)database.Differentially expressed genes(DEGs)between disease and control groups were identified using R software.Common DEGs were extracted via Venn diagram analysis.Gene ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analyses were conducted to identify biological processes and pathways associated with shared DEGs.Protein-protein interaction(PPI)networks were constructed,and candidate hub genes were ranked using the maximal clique centrality(MCC)algorithm.Further validation of hub gene expression was performed using 2 independent datasets.Receiver operating characteristic(ROC)curve analysis was used to evaluate the predictive value of key genes for OA and sarcopenia.Mouse models of OA and sarcopenia were established.Hematoxylin-eosin and Safranin O/Fast Green staining were used to validate the OA model.The sarcopenia model was validated via rotarod testing and quadriceps muscle mass measurement.Real-time reverse transcription PCR(real-time RT-PCR)was employed to assess the mRNA expression levels of candidate key genes in both models.Gene set enrichment analysis(GSEA)was conducted to identify pathways associated with the selected shared key genes in both diseases.Results:A total of 89 common DEGs were identified in the gene expression profiles of OA and sarcopenia,including 76 upregulated and 13 downregulated genes.These 89 DEGs were significantly enriched in protein digestion and absorption,the PI3K-Akt signaling pathway,and extracellular matrix-receptor interaction.PPI network analysis and MCC algorithm analysis of the 89 common DEGs identified the top 17 candidate hub genes.Based on the differential expression analysis of these 17 candidate hub genes in the validation datasets,AEBP1 and COL8A2 were ultimately selected as the common key genes for both diseases,both of which showed a significant upregulation trend in the disease groups(all P<0.05).The value of area under the curve(AUC)for AEBP1 and COL8A2 in the OA and sarcopenia datasets were all greater than 0.7,indicating that both genes have potential value in predicting OA and sarcopenia.Real-time RT-PCR results showed that the mRNA expression levels of AEBP1 and COL8A2 were significantly upregulated in the disease groups(all P<0.05),consistent with the results observed in the bioinformatics analysis.GSEA revealed that AEBP1 and COL8A2 were closely related to extracellular matrix-receptor interaction,ribosome,and oxidative phosphorylation in OA and sarcopenia.Conclusion:AEBP1 and COL8A2 have the potential to serve as common biomarkers for OA and sarcopenia.The extracellular matrix-receptor interaction pathway may represent a potential target for the prevention and treatment of both OA and sarcopenia.展开更多
The effect of key parameters on fatigue life of common metallic components, e.g. steel, aluminium alloy, has been analysed quantitatively. The influential coverage and degree of these parameters have been investigated...The effect of key parameters on fatigue life of common metallic components, e.g. steel, aluminium alloy, has been analysed quantitatively. The influential coverage and degree of these parameters have been investigated systematically, some phenomena which can′t be discovered with qualitative analysis method have been revealed, a series of valuable conclusions has been obtained, which would be very beneficial to fatigue resistant design and improvement of anti fatigue ability of metallic components.展开更多
Induction of tumor-specific cellular immune responseis very important in the cancer therapy. In this study,we used tumor antigen obtained by thaw of melanomacells to pulse M-CSF or/and IFN-γ gene-modificdmacrophages ...Induction of tumor-specific cellular immune responseis very important in the cancer therapy. In this study,we used tumor antigen obtained by thaw of melanomacells to pulse M-CSF or/and IFN-γ gene-modificdmacrophages before in viro infusion. Tumor membraneantigens could be phagocytosed by macrophages inculture. Antigen processing and mcxlulation of thepresentation can be achieved before macrophageinjection. The tumor antigens will be processedintracellularly by macrophages and thereafter展开更多
The French Society of Mineralogy and Crystallography is honoured to be invited to give a short presentation of its activity to the Chinese Society for Mineralogy,Petrology and Geochemistry.BRIEF HISTORY AND SOME FRENC...The French Society of Mineralogy and Crystallography is honoured to be invited to give a short presentation of its activity to the Chinese Society for Mineralogy,Petrology and Geochemistry.BRIEF HISTORY AND SOME FRENCH FOUNDERS OF展开更多
Aiming at the characteristics of multi-stage and(extremely)small samples of the identification problem of key effectiveness indexes of weapon equipment system-of-systems(WESoS),a Bayesian intelligent identification an...Aiming at the characteristics of multi-stage and(extremely)small samples of the identification problem of key effectiveness indexes of weapon equipment system-of-systems(WESoS),a Bayesian intelligent identification and inference model for system effectiveness assessment indexes based on dynamic grey incidence is proposed.The method uses multi-layer Bayesian techniques,makes full use of historical statistics and empirical information,and determines the Bayesian estima-tion of the incidence degree of indexes,which effectively solves the difficulties of small sample size of effectiveness indexes and difficulty in obtaining incidence rules between indexes.Sec-ondly,The method quantifies the incidence relationship between evaluation indexes and combat effectiveness based on Bayesian posterior grey incidence,and then identifies key system effec-tiveness evaluation indexes.Finally,the proposed method is applied to a case of screening key effectiveness indexes of a missile defensive system,and the analysis results show that the proposed method can fuse multi-moment information and extract multi-stage key indexes,and has good data extraction capability in the case of small samples.展开更多
Abstract:Doses of inhaled radionuclides received during evacuation might be correlated with amounts of those radionuclides on an evacuee's body surface. The purpose of the present study was to estimate thyroid equ...Abstract:Doses of inhaled radionuclides received during evacuation might be correlated with amounts of those radionuclides on an evacuee's body surface. The purpose of the present study was to estimate thyroid equivalent doses based on body surface contamination measured with a Geiger-Mueller survey meter on 2,087 evacuees from Tomioka, Okuma, Futaba, Naraha, Namie.展开更多
Heat shock protein 90 (Hsp90) is a major heatshock protein whose functions are necessary for livingorganisms, including both procaryotes and eucaryotes.Human Hsp90 consists of two forms, Hsp90α andHsp90β. Expression...Heat shock protein 90 (Hsp90) is a major heatshock protein whose functions are necessary for livingorganisms, including both procaryotes and eucaryotes.Human Hsp90 consists of two forms, Hsp90α andHsp90β. Expression of Hsp90α appears to be inducible bydifferent stimuli. Adenovirus EIA gene products andtransformation with the H-ras oncogene can induce aselective overexpression of Hsp90α. Hsp90α was展开更多
As the mission needs of the autonomous underwater vehicles(AUV) have become increasingly varied and complex,the AUVs are developing in the direction of systematism, multifunction, and clustering technology, which prom...As the mission needs of the autonomous underwater vehicles(AUV) have become increasingly varied and complex,the AUVs are developing in the direction of systematism, multifunction, and clustering technology, which promotes the progress of key technologies and proposes a series of technical problems. Therefore, it is necessary to make systemic analysis and in-depth study for the progress of AUV's key technologies and innovative applications. The multi-functional mission needs and its key technologies involved in complex sea conditions are pointed out through analyzing the domestic and foreign technical programs, functional characteristics and future development plans. Furthermore, the overall design of a multi-moving state AUV is proposed. Then, technical innovations of the key technologies, such as thrust vector, propeller design, kinematics and dynamics, navigation control, and ambient flow field characteristics, are made, combining with the structural characteristics and motion characteristics of the new multi-moving state AUV. The results verify the good performance of the multi-moving state AUV and provide a theoretical guidance and technical support for the design of new AUV in real complex sea conditions.展开更多
The Micius satellite was successfully launched on 16 August 2016,from Jiuquan,China,orbiting at an altitude of about 500 km.The main scientific goals,including satellite-to-ground quantum key distribution,satellite-ba...The Micius satellite was successfully launched on 16 August 2016,from Jiuquan,China,orbiting at an altitude of about 500 km.The main scientific goals,including satellite-to-ground quantum key distribution,satellite-based quantum entanglement distribution,ground-to-satellite quantum teleportation,and satellite relayed intercontinental quantum network,were achieved in 2017.As a starting point,the Micius satellite has become a platform for quantum science experiments at the space scale.Here,we introduce the latest experimental achievements(in 2018–2020)based on the Micius satellite.展开更多
Since the 1 960 s,many successful space missions have highlighted the advantages and necessity of humans in the exploration of space,but scientists have long worried about the adverse effects of spaceflight on Astrona...Since the 1 960 s,many successful space missions have highlighted the advantages and necessity of humans in the exploration of space,but scientists have long worried about the adverse effects of spaceflight on Astronaut.Space flight and models that create conditions similar to those that occur during space flight have been shown to deleteriously affect a variety of immunological responses.The mechanisms and biomedical consequences of these changes remain to be established.Conducting experiments in an environment of true microgravity requires a roundtrip ticket into space,a feat that is both expensive and challenging.Simulated microgravity(SMG)models allow scientists to gather preliminary data without the cost and logistical challenges of spaceflight.The objective of the present study was to evaluate the effects of SMG on immunity function of macrophages that exposed to RPM and RCCS separately.While many studies have demonstrated that alterations occur in the immune system as a result of space travel,the level at which these mechanisms exert their effect,at the level of the mature immune cell or earlier at the progenitor or stem cell stage is not known.In particular,macrophages,as one of the most important immune cells and play a key role in both specific and non-specific immunity,did not have received much attention.Therefore,in our study,we mainly study the influence of microgravity on the immune function of macrophages.In this study,we evaluated the immune dysfunction of macrophages under SMG.Firstly,we found that the morphology and structure of the macrophages were changed,specifically,we observed that there were more protrusions on cell surface and the cells were shrinking significantly after exposure to SMG.Secondly,we demonstrated that under simulated microgravity(SMG)conditions,the phagocytic and proliferative functions of macrophages were significantly reduced.Thirdly,several processes,including surface receptor expression,cytoskeleton,and cytokines secreted were investigated in macrophages under SMG.Phagocytosis is one of the important means for macrophages to exert immune function,and cell surface phagocytosis-related receptors play an important role.Here,we selected four common receptors(TLR2,FcyR1,CD11b and CD 18)to detect.The results indicate that SMG(RPM and RCCS)have a great influence on the expression of surface phagocytosis-related receptors,which may be one of the main reasons for the decline of immune function ofmacrophages.Macrophages exert immune function through phagocytosis,and the cytoskeleton plays an important role in the process of phagocytosis.The results indicate that SMG(RPM and RCCS)have a great influence on the expression of cytoskeleton-related proteins,which provides me with a new idea that SMG may regulate immunity of macrophage by affecting the cytoskeleton.Immune-related cytokines play an important role in macrophage immune process.Here,we selected four common immunocytokine(TNF-α,IL-1β,IL-6 and IL-10)to detect.The change of these four immunocytokine further demonstrate that SMG significantly decline the immunity of macrophage,we must pay enough attention to the impact of SMG on macrophage.The above factors such as the changes of morphology and structure of the macrophages and the decreased expression of Arp2/3 complex related proteins,cytokine secretion,and cell surface receptors may be responsible for the immune dysfunction of macrophages under SMG.展开更多
Group key distribution is faced with two important problems, i.e. reliability and scalability, to support security multicast for large and dynamic groups. With group member increasing, traditional reliable multicast p...Group key distribution is faced with two important problems, i.e. reliability and scalability, to support security multicast for large and dynamic groups. With group member increasing, traditional reliable multicast protocol can not deal with them fully. Gossip-based group key distribution idea for wide-area dissemination was provided. It is based on an gossip-based loss recovery control mechanism. It can provide a probabilistic reliable guarantee for a information dissemination to reach every group member, which can achieve scalability and reliability. To achieve full reliability, three layers protocol model in group key distribution was provided. One is best effect layer, which provides unreliable dissemination. Other is gossip-based loss recovery layer, which provides probabilistic reliable guarantee. Last is vsync-based layer, which provide deterministic loss recovery. We integrate probabilistic loss recovery method with deterministic one. The model possess scalability that probabilistic method has and full reliability prosthesis by vsync-based. To evaluate the effectiveness of gossip technique in scalable and reliable multicast protocols. We have compared gossip protocol with other reliable multicast protocols. Experimental result shows that gossip protocol has better scalability than other.展开更多
In the 21st century,a new round of scientifi c and technological revolution represented by digitalization,networking and intelligence has caused a change in the scientific research paradigm,and the research of complex...In the 21st century,a new round of scientifi c and technological revolution represented by digitalization,networking and intelligence has caused a change in the scientific research paradigm,and the research of complex systems has become the main driving force for the change of the scientific research paradigm.展开更多
文摘The thermal-induced error is a very important sour ce of machining errors of machine tools. To compensate the thermal-induced machin ing errors, a relationship model between the thermal field and deformations was needed. The relationship can be deduced by virtual of FEM (Finite Element Method ), ANN (Artificial Neural Network) or MRA (Multiple Regression Analysis). MR A is on the basis of a total understanding of the temperature distribution of th e machine tool. Although the more the temperatures measured are, the more accura te the MRA is, too more temperatures will hinder the analysis calculation. So it is necessary to identify the key temperatures of the machine tool. The selectio n of key temperatures decides the efficiency and precision of MRA. Because of th e complexities and multi-input and multi-output structure of the relationships , the exact quantitative portions as well as the unclear portions must be taken into consideration together to improve the identification of key temperatures. I n this paper, a fuzzy cluster analysis was used to select the key temperatures. The substance of identifying the key temperatures is to group all temperatures b y their relativity, and then to select a temperature from each group as the repr esentation. A fuzzy cluster analysis can uncover the relationships between t he thermal field and deformations more truly and thoroughly. A fuzzy cluster ana lysis is the cluster analysis based on fuzzy sets. Given U={u i|i=0,...,N}, in which u i is the temperature measured, a fuzzy matrix R can be obta ined. The transfer close package t(R) can be deduced from R. A fuzzy clu ster of U then conducts on the basis of t(R). Based on the fuzzy cluster analysis discussed above, this paper identified the k ey temperatures of a horizontal machining center. The number of the temperatures measured was reduced to 4 from 32, and then the multiple regression relationshi p models between the 4 temperatures and the thermal deformations of the spindle were drawn. The remnant errors between the regression models and measured deform ations reached a satisfying low level. At the same time, the decreasing of tempe rature variable number improved the efficiency of measure and analysis greatly.
文摘Introduction There are big disputes on the uplift of the Tibetan Plateau. Some scientists believe the plateau uplifted to its highest elevation by 14Ma BP,and it decreased in elevation afterward. The second idea about the uplift of the plateau was similar to the first one in tectonic theory, but they consider the time of C3 plant change to C4 in the South Asia, as the time when the plateau reached its highest elevation. This time is 8Ma BP. The third idea, the most Chinese scientists believed, the nearest uplift of the plateau took place since 3 4Ma BP. The occurrence of fault depression and gravel deposit with large thickness in the inner and the marge of the plateau represented the speed uplift. After the collision of the India plate and the Eurasia plateau by the 36Ma, the Tibetean area uplifted several times, but it had been planed to lower area. The plateau with 4500m elevation formed in the Quaternary. While our recent research in the Kunlun Pass area suggest , the nearest uplift occurred at the border of the Early and Middle Pleistocene, and before that time, the elevation of this area was no more than 1500 m.
基金supported by the National Natural Science Foundation of China(82060418).
文摘Objective:Osteoarthritis(OA)and sarcopenia are significant health concerns in the elderly,substantially impacting their daily activities and quality of life.However,the relationship between them remains poorly understood.This study aims to uncover common biomarkers and pathways associated with both OA and sarcopenia.Methods:Gene expression profiles related to OA and sarcopenia were retrieved from the Gene Expression Omnibus(GEO)database.Differentially expressed genes(DEGs)between disease and control groups were identified using R software.Common DEGs were extracted via Venn diagram analysis.Gene ontology(GO)and Kyoto Encyclopedia of Genes and Genomes(KEGG)enrichment analyses were conducted to identify biological processes and pathways associated with shared DEGs.Protein-protein interaction(PPI)networks were constructed,and candidate hub genes were ranked using the maximal clique centrality(MCC)algorithm.Further validation of hub gene expression was performed using 2 independent datasets.Receiver operating characteristic(ROC)curve analysis was used to evaluate the predictive value of key genes for OA and sarcopenia.Mouse models of OA and sarcopenia were established.Hematoxylin-eosin and Safranin O/Fast Green staining were used to validate the OA model.The sarcopenia model was validated via rotarod testing and quadriceps muscle mass measurement.Real-time reverse transcription PCR(real-time RT-PCR)was employed to assess the mRNA expression levels of candidate key genes in both models.Gene set enrichment analysis(GSEA)was conducted to identify pathways associated with the selected shared key genes in both diseases.Results:A total of 89 common DEGs were identified in the gene expression profiles of OA and sarcopenia,including 76 upregulated and 13 downregulated genes.These 89 DEGs were significantly enriched in protein digestion and absorption,the PI3K-Akt signaling pathway,and extracellular matrix-receptor interaction.PPI network analysis and MCC algorithm analysis of the 89 common DEGs identified the top 17 candidate hub genes.Based on the differential expression analysis of these 17 candidate hub genes in the validation datasets,AEBP1 and COL8A2 were ultimately selected as the common key genes for both diseases,both of which showed a significant upregulation trend in the disease groups(all P<0.05).The value of area under the curve(AUC)for AEBP1 and COL8A2 in the OA and sarcopenia datasets were all greater than 0.7,indicating that both genes have potential value in predicting OA and sarcopenia.Real-time RT-PCR results showed that the mRNA expression levels of AEBP1 and COL8A2 were significantly upregulated in the disease groups(all P<0.05),consistent with the results observed in the bioinformatics analysis.GSEA revealed that AEBP1 and COL8A2 were closely related to extracellular matrix-receptor interaction,ribosome,and oxidative phosphorylation in OA and sarcopenia.Conclusion:AEBP1 and COL8A2 have the potential to serve as common biomarkers for OA and sarcopenia.The extracellular matrix-receptor interaction pathway may represent a potential target for the prevention and treatment of both OA and sarcopenia.
基金TheFoundationforScholarsReturnedfromOverseaCNNC! (No .970 48 2 )
文摘The effect of key parameters on fatigue life of common metallic components, e.g. steel, aluminium alloy, has been analysed quantitatively. The influential coverage and degree of these parameters have been investigated systematically, some phenomena which can′t be discovered with qualitative analysis method have been revealed, a series of valuable conclusions has been obtained, which would be very beneficial to fatigue resistant design and improvement of anti fatigue ability of metallic components.
文摘Induction of tumor-specific cellular immune responseis very important in the cancer therapy. In this study,we used tumor antigen obtained by thaw of melanomacells to pulse M-CSF or/and IFN-γ gene-modificdmacrophages before in viro infusion. Tumor membraneantigens could be phagocytosed by macrophages inculture. Antigen processing and mcxlulation of thepresentation can be achieved before macrophageinjection. The tumor antigens will be processedintracellularly by macrophages and thereafter
文摘The French Society of Mineralogy and Crystallography is honoured to be invited to give a short presentation of its activity to the Chinese Society for Mineralogy,Petrology and Geochemistry.BRIEF HISTORY AND SOME FRENCH FOUNDERS OF
基金supported by the National Natural Science Foundation of China(72271124,72071111).
文摘Aiming at the characteristics of multi-stage and(extremely)small samples of the identification problem of key effectiveness indexes of weapon equipment system-of-systems(WESoS),a Bayesian intelligent identification and inference model for system effectiveness assessment indexes based on dynamic grey incidence is proposed.The method uses multi-layer Bayesian techniques,makes full use of historical statistics and empirical information,and determines the Bayesian estima-tion of the incidence degree of indexes,which effectively solves the difficulties of small sample size of effectiveness indexes and difficulty in obtaining incidence rules between indexes.Sec-ondly,The method quantifies the incidence relationship between evaluation indexes and combat effectiveness based on Bayesian posterior grey incidence,and then identifies key system effec-tiveness evaluation indexes.Finally,the proposed method is applied to a case of screening key effectiveness indexes of a missile defensive system,and the analysis results show that the proposed method can fuse multi-moment information and extract multi-stage key indexes,and has good data extraction capability in the case of small samples.
文摘Abstract:Doses of inhaled radionuclides received during evacuation might be correlated with amounts of those radionuclides on an evacuee's body surface. The purpose of the present study was to estimate thyroid equivalent doses based on body surface contamination measured with a Geiger-Mueller survey meter on 2,087 evacuees from Tomioka, Okuma, Futaba, Naraha, Namie.
文摘Heat shock protein 90 (Hsp90) is a major heatshock protein whose functions are necessary for livingorganisms, including both procaryotes and eucaryotes.Human Hsp90 consists of two forms, Hsp90α andHsp90β. Expression of Hsp90α appears to be inducible bydifferent stimuli. Adenovirus EIA gene products andtransformation with the H-ras oncogene can induce aselective overexpression of Hsp90α. Hsp90α was
基金Project(ZR2014EEP019) supported by the Natural Science Foundation of Shandong Province,ChinaProject(51505491) supported by the National Natural Science Foundation of China
文摘As the mission needs of the autonomous underwater vehicles(AUV) have become increasingly varied and complex,the AUVs are developing in the direction of systematism, multifunction, and clustering technology, which promotes the progress of key technologies and proposes a series of technical problems. Therefore, it is necessary to make systemic analysis and in-depth study for the progress of AUV's key technologies and innovative applications. The multi-functional mission needs and its key technologies involved in complex sea conditions are pointed out through analyzing the domestic and foreign technical programs, functional characteristics and future development plans. Furthermore, the overall design of a multi-moving state AUV is proposed. Then, technical innovations of the key technologies, such as thrust vector, propeller design, kinematics and dynamics, navigation control, and ambient flow field characteristics, are made, combining with the structural characteristics and motion characteristics of the new multi-moving state AUV. The results verify the good performance of the multi-moving state AUV and provide a theoretical guidance and technical support for the design of new AUV in real complex sea conditions.
文摘The Micius satellite was successfully launched on 16 August 2016,from Jiuquan,China,orbiting at an altitude of about 500 km.The main scientific goals,including satellite-to-ground quantum key distribution,satellite-based quantum entanglement distribution,ground-to-satellite quantum teleportation,and satellite relayed intercontinental quantum network,were achieved in 2017.As a starting point,the Micius satellite has become a platform for quantum science experiments at the space scale.Here,we introduce the latest experimental achievements(in 2018–2020)based on the Micius satellite.
文摘Since the 1 960 s,many successful space missions have highlighted the advantages and necessity of humans in the exploration of space,but scientists have long worried about the adverse effects of spaceflight on Astronaut.Space flight and models that create conditions similar to those that occur during space flight have been shown to deleteriously affect a variety of immunological responses.The mechanisms and biomedical consequences of these changes remain to be established.Conducting experiments in an environment of true microgravity requires a roundtrip ticket into space,a feat that is both expensive and challenging.Simulated microgravity(SMG)models allow scientists to gather preliminary data without the cost and logistical challenges of spaceflight.The objective of the present study was to evaluate the effects of SMG on immunity function of macrophages that exposed to RPM and RCCS separately.While many studies have demonstrated that alterations occur in the immune system as a result of space travel,the level at which these mechanisms exert their effect,at the level of the mature immune cell or earlier at the progenitor or stem cell stage is not known.In particular,macrophages,as one of the most important immune cells and play a key role in both specific and non-specific immunity,did not have received much attention.Therefore,in our study,we mainly study the influence of microgravity on the immune function of macrophages.In this study,we evaluated the immune dysfunction of macrophages under SMG.Firstly,we found that the morphology and structure of the macrophages were changed,specifically,we observed that there were more protrusions on cell surface and the cells were shrinking significantly after exposure to SMG.Secondly,we demonstrated that under simulated microgravity(SMG)conditions,the phagocytic and proliferative functions of macrophages were significantly reduced.Thirdly,several processes,including surface receptor expression,cytoskeleton,and cytokines secreted were investigated in macrophages under SMG.Phagocytosis is one of the important means for macrophages to exert immune function,and cell surface phagocytosis-related receptors play an important role.Here,we selected four common receptors(TLR2,FcyR1,CD11b and CD 18)to detect.The results indicate that SMG(RPM and RCCS)have a great influence on the expression of surface phagocytosis-related receptors,which may be one of the main reasons for the decline of immune function ofmacrophages.Macrophages exert immune function through phagocytosis,and the cytoskeleton plays an important role in the process of phagocytosis.The results indicate that SMG(RPM and RCCS)have a great influence on the expression of cytoskeleton-related proteins,which provides me with a new idea that SMG may regulate immunity of macrophage by affecting the cytoskeleton.Immune-related cytokines play an important role in macrophage immune process.Here,we selected four common immunocytokine(TNF-α,IL-1β,IL-6 and IL-10)to detect.The change of these four immunocytokine further demonstrate that SMG significantly decline the immunity of macrophage,we must pay enough attention to the impact of SMG on macrophage.The above factors such as the changes of morphology and structure of the macrophages and the decreased expression of Arp2/3 complex related proteins,cytokine secretion,and cell surface receptors may be responsible for the immune dysfunction of macrophages under SMG.
文摘Group key distribution is faced with two important problems, i.e. reliability and scalability, to support security multicast for large and dynamic groups. With group member increasing, traditional reliable multicast protocol can not deal with them fully. Gossip-based group key distribution idea for wide-area dissemination was provided. It is based on an gossip-based loss recovery control mechanism. It can provide a probabilistic reliable guarantee for a information dissemination to reach every group member, which can achieve scalability and reliability. To achieve full reliability, three layers protocol model in group key distribution was provided. One is best effect layer, which provides unreliable dissemination. Other is gossip-based loss recovery layer, which provides probabilistic reliable guarantee. Last is vsync-based layer, which provide deterministic loss recovery. We integrate probabilistic loss recovery method with deterministic one. The model possess scalability that probabilistic method has and full reliability prosthesis by vsync-based. To evaluate the effectiveness of gossip technique in scalable and reliable multicast protocols. We have compared gossip protocol with other reliable multicast protocols. Experimental result shows that gossip protocol has better scalability than other.
文摘In the 21st century,a new round of scientifi c and technological revolution represented by digitalization,networking and intelligence has caused a change in the scientific research paradigm,and the research of complex systems has become the main driving force for the change of the scientific research paradigm.
文摘The moditication of tumor cells or effcor cellsusing cytokine genes as a strategy to enhance hostantitumor immunity has been studied intensively over
