In recent years,blockchain technology integration and application has gradually become an important driving force for new technological innovation and industrial transformation.While blockchain technology and applicat...In recent years,blockchain technology integration and application has gradually become an important driving force for new technological innovation and industrial transformation.While blockchain technology and applications are developing rapidly,the emerging security risks and obstacles have gradually become prominent.Attackers can still find security issues in blockchain systems and conduct attacks,causing increasing losses from network attacks every year.In response to the current demand for blockchain application security detection and assessment in all industries,and the insufficient coverage of existing detection technologies such as smart contract detectiontechnology,this paper proposes a blockchain core technology security assessment system model,and studies the relevant detection and assessment key technologies and systems.A security assessment scheme based on a smart contract and consensus mechanism detection scheme is designed.And the underlying blockchain architecture supports the traceability of detection results using super blockchains.Finally,the functionality and performance of the system were tested,and the test results show that the model and solutions proposed in this paper have good feasibility.展开更多
A simple creep testing method is presented which involves using coiled specimens. With this method, a single experiment can give all the data required for a plot of strain rate versus stress. The value of the stress-e...A simple creep testing method is presented which involves using coiled specimens. With this method, a single experiment can give all the data required for a plot of strain rate versus stress. The value of the stress-expo-nent of room temperature steady-state creep a Pb-61. 5wt %Sn solder was measured in this way to be 1. 06,aselected from a diffusion creep mechanism.展开更多
The present research exploits diffusion brazing of mechanically alloyed Y 2O_3 dispersion strengthened nick-el-base MA760 and iron-base MA956 alloys using B-and P-containing thin foil and sputter coated interlayers.Mi...The present research exploits diffusion brazing of mechanically alloyed Y 2O_3 dispersion strengthened nick-el-base MA760 and iron-base MA956 alloys using B-and P-containing thin foil and sputter coated interlayers.Microstructures of diffission brazed interface before and after recrystallization annealing were investigated usingoptical metallography, electron microprobe analysis, and transmission electron microscopy. It has been foundthat B and P have a strons influence on the recrystallization behavior of these materials. Too high B or P levelsin the interlayers caused recrystallization of the base alloys during brazing process which was operated at temperatures below normal recrystallization points.展开更多
A differential-speed rolling(DSR) was applied to AZ31 magnesium alloy sample at different rolling temperatures of 473,523,573,and 623 K with 1-pass and 2-pass operations.The microstructural evolution and mechanical pr...A differential-speed rolling(DSR) was applied to AZ31 magnesium alloy sample at different rolling temperatures of 473,523,573,and 623 K with 1-pass and 2-pass operations.The microstructural evolution and mechanical properties of the deformed samples were investigated.The rolling temperature was found to be an important parameter affecting the microstructural development.After DSR at 473 K,the microstructure was more homogeneous than that obtained after deformation by equal-speed rolling(ESR).The fully recrystallized microstructures were generated after DSR at 573 and 623 K.As to mechanical properties,the yield strength(YS) and ultimate tensile strength(UTS) decreased monotonously with increasing rolling temperature.In contrast,the elongation of the DSR-deformed samples was improved as the rolling temperature increased.The strain hardening exponent(n) calculated by Hollomon equation increased with increasing the rolling temperature,which would explain an increase in the uniform elongation.展开更多
P507 solvent extraction is the main method to separate and purify the rare earth products.The emulsification may be caused by the impurities in process of extracting rare earths,and these result in huge economic loss ...P507 solvent extraction is the main method to separate and purify the rare earth products.The emulsification may be caused by the impurities in process of extracting rare earths,and these result in huge economic loss and decrease the quality of rare earth products.In recent researches,the extractant was prone to emulsification,and aluminum content of rare earth products also increased,while aluminum concentration of feed was higher.Pointing to this problem,the structural change of saponification P507 extracting aluminum and lanthanum was investigated by infrared spectroscopy,and the results showed that Al ions exchanged with H of P-O-H to become P-O-Al.Because aluminum held the characteristic of hydrophilic after extracted in the form of hydroxyl polymer ions and this provided conditions for the formation of micro emulsion.The organic phase and aqueous phase were investigated by polarizing microscope after aluminum was extracted.The results showed that the organic phase was clear when the extraction capacity of Al was less than 5 g/L.If the extraction capacity of Al exceeded 5 g/L,it formed W/O of ME(micro emulsion),leading to form emulsion of the organic phase.When Al concentration of feed was less than 1 g/L,the aqueous phase would form O/W of ME.If aluminum was extracted by saponification P507 firstly,then the the organic phase loading aluminum extracted rare earth continually,the organic and aqueous phase formed emulsification easily.展开更多
The connotation of rural public goods is expounded.The rural public goods refer to the products and labors that satisfy the production and living of rural residents,economic growth and social progress.The rural public...The connotation of rural public goods is expounded.The rural public goods refer to the products and labors that satisfy the production and living of rural residents,economic growth and social progress.The rural public goods is characterized by non-excludability,non-competitiveness and indispensability of other general public goods.The supply situation of Chinese government to rural public goods is analyzed,as well as the demand situation of rural public goods,which includes farmers' demand on training,the assistance demand of rural weak groups,farmers' demand on comfortable living conditions and farmers' demand on "soft" public goods.The paths for innovating the supply mechanism of rural public goods are put forward,which cover perfecting the decision mechanism of public goods supply;scientifically distributing the supply responsibility of rural public goods;facilitating the reform of each supporting equipment and exploring the multiple capital collecting channels of rural public goods.展开更多
In the process of establishing the unified market of construction land between city and countryside,both of the market mechanism and the government mechanism are indispensable to the allocation of resources,but they a...In the process of establishing the unified market of construction land between city and countryside,both of the market mechanism and the government mechanism are indispensable to the allocation of resources,but they are both powerless in some ways. This paper starts from the related theory of economics,and draws a conclusion that the unified market of construction land between urban countryside will be established unless the market mechanism and the government mechanism work collaboratively. Finally,the paper puts forward the recommendations for ensuring the coordination between market mechanism and government mechanism: reforming the agricultural land property rights system; reforming the existing land law system; establishing the modern land tax system; transforming the government functions.展开更多
Using acridine dyes as sensitizers,the photoisomerization of three norbornadiene derivatives was investigated.The valence isomerization of nor- bornadiene derivatives(Ⅰ_a,Ⅰ_b,Ⅰ_c)gave their corresponding isomers of...Using acridine dyes as sensitizers,the photoisomerization of three norbornadiene derivatives was investigated.The valence isomerization of nor- bornadiene derivatives(Ⅰ_a,Ⅰ_b,Ⅰ_c)gave their corresponding isomers of quadri- cyclane(Ⅱ_a,Ⅱ_b,Ⅱ_c)operating with relatively high efficiency in an electron transfer mode.Their quantum yields of isomerization were determined and the reaction mechanism was discussed.展开更多
Involuntary resettlenment caused by project construction is a difficult problem over world. In the past, therestoration of livelihoods in the event of involuntary resettlementhas been based purely on providing compen...Involuntary resettlenment caused by project construction is a difficult problem over world. In the past, therestoration of livelihoods in the event of involuntary resettlementhas been based purely on providing compensation to those who are displaced. Evidence has shown that compensation-based involuntary resettlement can not realize the objective of restoring and improving resettlers＇ living standard. With a view to improve this outcome, the concept of Resettlement with Development （RwD） was envisaged and is now generally heralded as the means to mitigate catastrophic failures of the past. However, few developing countries have included the concept of RwD into th, ational policies and China is one of them. The Chinese government has taken resettlement as an opportunity to help resettlers restore and improve their living standards and develop economy in reservoir areas by implementing RwD olicy including giving compensation and subsidies at early stage and offering production assistance at late stage, citing up reservoir construction fund, initiating partnership programs and preferential policy as well as enhanc infrastruture construction. The preliminary experience from the TGP resettlement has verified that the transformation from compensation-based resettlement to RwD is a right policy, choice. Meanwhile. because ofthe changing political environment and the complexity of involuntary resettlement there is still room for china to improve its RwD policy.展开更多
In recent years, with the continuous progress of science and technology, the development of information technology has also begun to change. The popularity of the application of modern information technology in the fi...In recent years, with the continuous progress of science and technology, the development of information technology has also begun to change. The popularity of the application of modern information technology in the field of education is very high. College students can obtain the knowledge and content they need from the network. Teachers are no longer the only source of information for students, which promotes the improvement of students academic performance and cultivates students autonomous learning ability. As a university teacher, the author discusses how to motivate college students autonomous learning in the process of virtual project-based practical teaching, hoping that this paper can provide a certain direction for the future development of university education and guide college students to cultivate their autonomous learning ability.展开更多
Cross-coupling reactions between aryl halides and thiolates or selenolates typically require transition metals,photocatalysts,strong bases,or/and malodorous thiols/selenols,with various mechanisms proposed.This study ...Cross-coupling reactions between aryl halides and thiolates or selenolates typically require transition metals,photocatalysts,strong bases,or/and malodorous thiols/selenols,with various mechanisms proposed.This study aims to leverage a new application of neutral ChB to address these challenges and enable a very simple photoinduced cross-electrophile C—S/Se coupling using readily available chalcogen electrophiles.Mechanistic investigations have revealed the important role of neutral ChB in facilitating single electron transfer processes,thereby enabling the generation of thiolates/selenolates from stable chalcogen electrophiles andα-aminoalkyl radicals,which possess the capability to abstract halogen atoms from aryl iodides.Moreover,the study provided support for the radical nucleophilic substitution mechanism.展开更多
Egg recognition is a variable but common anti-parasitism defense among different species of birds with brood parasites.In contrast,nestling recognition is rare.Very few studies have found nestling recognition in brood...Egg recognition is a variable but common anti-parasitism defense among different species of birds with brood parasites.In contrast,nestling recognition is rare.Very few studies have found nestling recognition in brood parasite hosts and determined the rejection mechanism behind this behavior.Hosts may use the number of hatchling downfeathers to reject parasite nestlings.We tested whether hatchling down-feathers is a visual cue for the red-rumped swallow,a host that can recognize and reject parasite nestlings.Our results indicated that red-rumped swallows do not recognize foreign nestlings based on hatchling down-feathers.The closed nest structure and hatchling morph may explain the absence of such a mechanism.None of the rejection mechanisms found in previous studies could explain the nestling recognition in swallows.Olfactory cues,tactile cues,or other visual cues,except for single nestling or hatchling down-feathers,may provide nestling recognition in red-rumped swallows.More study is needed to evaluate these possibilities.展开更多
Sterile α motif and histidine/aspartic acid domain containing protein 1 (SAMHD1) is a deoxynucleoside triphosphate (dNTPs) triphosphohydrolase that can hydrolyze dNTPs into deoxynucleosides and triphosphates to keep ...Sterile α motif and histidine/aspartic acid domain containing protein 1 (SAMHD1) is a deoxynucleoside triphosphate (dNTPs) triphosphohydrolase that can hydrolyze dNTPs into deoxynucleosides and triphosphates to keep the balance of the intracellular dNTPs pool. Moreover, it has been reported that SAMHD1 plays a role in regulating cell proliferation and the cell cycle, maintaining genome stability and inhibiting innate immune responses. SAMHD1 activity is regulated by phosphorylation, oxidation, SUMOylation, and O-GlcNAcylation. SAMHD1 mutations have been reported to cause diseases, including chronic lymphocytic leukemia and mantle cell lymphoma. SAMHD1 expression in acute myeloid leukemia predicts inferior prognosis. Recently, it has been revealed that SAMHD1 mediates the resistance to anti-cancer drugs. This review will focus on SAMHD1 function and regulation, the association between SAMHD1 and hematological malignancies and will provide updated information on SAMHD1 mediating resistance to nucleoside analogue antimetabolites, topoisomerase inhibitors, platinum-derived agents and DNA hypomethylating agents. Furthermore, histone deacetylase inhibitors and tyrosine kinase inhibitors indirectly increase anti-cancer drug resistance by increasing SAMDH1 activity. We herein highlight the importance of the development of novel agents targeting SAMHD1 to overcome treatment resistance of hematological malignancies, which would be an opportunity to improve the outcome of patients with refractory hematological malignancies.展开更多
基金supported by Education and Scientific Research Special Project of Fujian Provincial Department of Finance(Research on the Application of Blockchain Technology in Prison Law Enforcement Management),Fujian Provincial Social Science Foundation Public Security Theory Research Project(FJ2023TWGA004).
文摘In recent years,blockchain technology integration and application has gradually become an important driving force for new technological innovation and industrial transformation.While blockchain technology and applications are developing rapidly,the emerging security risks and obstacles have gradually become prominent.Attackers can still find security issues in blockchain systems and conduct attacks,causing increasing losses from network attacks every year.In response to the current demand for blockchain application security detection and assessment in all industries,and the insufficient coverage of existing detection technologies such as smart contract detectiontechnology,this paper proposes a blockchain core technology security assessment system model,and studies the relevant detection and assessment key technologies and systems.A security assessment scheme based on a smart contract and consensus mechanism detection scheme is designed.And the underlying blockchain architecture supports the traceability of detection results using super blockchains.Finally,the functionality and performance of the system were tested,and the test results show that the model and solutions proposed in this paper have good feasibility.
文摘A simple creep testing method is presented which involves using coiled specimens. With this method, a single experiment can give all the data required for a plot of strain rate versus stress. The value of the stress-expo-nent of room temperature steady-state creep a Pb-61. 5wt %Sn solder was measured in this way to be 1. 06,aselected from a diffusion creep mechanism.
文摘The present research exploits diffusion brazing of mechanically alloyed Y 2O_3 dispersion strengthened nick-el-base MA760 and iron-base MA956 alloys using B-and P-containing thin foil and sputter coated interlayers.Microstructures of diffission brazed interface before and after recrystallization annealing were investigated usingoptical metallography, electron microprobe analysis, and transmission electron microscopy. It has been foundthat B and P have a strons influence on the recrystallization behavior of these materials. Too high B or P levelsin the interlayers caused recrystallization of the base alloys during brazing process which was operated at temperatures below normal recrystallization points.
基金supported by the research grant funded by the national research foundation(NRF-2014R1A1A2059004)
文摘A differential-speed rolling(DSR) was applied to AZ31 magnesium alloy sample at different rolling temperatures of 473,523,573,and 623 K with 1-pass and 2-pass operations.The microstructural evolution and mechanical properties of the deformed samples were investigated.The rolling temperature was found to be an important parameter affecting the microstructural development.After DSR at 473 K,the microstructure was more homogeneous than that obtained after deformation by equal-speed rolling(ESR).The fully recrystallized microstructures were generated after DSR at 573 and 623 K.As to mechanical properties,the yield strength(YS) and ultimate tensile strength(UTS) decreased monotonously with increasing rolling temperature.In contrast,the elongation of the DSR-deformed samples was improved as the rolling temperature increased.The strain hardening exponent(n) calculated by Hollomon equation increased with increasing the rolling temperature,which would explain an increase in the uniform elongation.
基金Project supported by the National Natural Science Foundation of China (50974042)Scientific Research Special Foundation of Doctor Subject of Chinese Universities (20090042120015)the Fundamental Research Funds for the Central Universities (N090302007)
文摘P507 solvent extraction is the main method to separate and purify the rare earth products.The emulsification may be caused by the impurities in process of extracting rare earths,and these result in huge economic loss and decrease the quality of rare earth products.In recent researches,the extractant was prone to emulsification,and aluminum content of rare earth products also increased,while aluminum concentration of feed was higher.Pointing to this problem,the structural change of saponification P507 extracting aluminum and lanthanum was investigated by infrared spectroscopy,and the results showed that Al ions exchanged with H of P-O-H to become P-O-Al.Because aluminum held the characteristic of hydrophilic after extracted in the form of hydroxyl polymer ions and this provided conditions for the formation of micro emulsion.The organic phase and aqueous phase were investigated by polarizing microscope after aluminum was extracted.The results showed that the organic phase was clear when the extraction capacity of Al was less than 5 g/L.If the extraction capacity of Al exceeded 5 g/L,it formed W/O of ME(micro emulsion),leading to form emulsion of the organic phase.When Al concentration of feed was less than 1 g/L,the aqueous phase would form O/W of ME.If aluminum was extracted by saponification P507 firstly,then the the organic phase loading aluminum extracted rare earth continually,the organic and aqueous phase formed emulsification easily.
文摘The connotation of rural public goods is expounded.The rural public goods refer to the products and labors that satisfy the production and living of rural residents,economic growth and social progress.The rural public goods is characterized by non-excludability,non-competitiveness and indispensability of other general public goods.The supply situation of Chinese government to rural public goods is analyzed,as well as the demand situation of rural public goods,which includes farmers' demand on training,the assistance demand of rural weak groups,farmers' demand on comfortable living conditions and farmers' demand on "soft" public goods.The paths for innovating the supply mechanism of rural public goods are put forward,which cover perfecting the decision mechanism of public goods supply;scientifically distributing the supply responsibility of rural public goods;facilitating the reform of each supporting equipment and exploring the multiple capital collecting channels of rural public goods.
基金Supported by National Social Science Fund Project(13BJY095)
文摘In the process of establishing the unified market of construction land between city and countryside,both of the market mechanism and the government mechanism are indispensable to the allocation of resources,but they are both powerless in some ways. This paper starts from the related theory of economics,and draws a conclusion that the unified market of construction land between urban countryside will be established unless the market mechanism and the government mechanism work collaboratively. Finally,the paper puts forward the recommendations for ensuring the coordination between market mechanism and government mechanism: reforming the agricultural land property rights system; reforming the existing land law system; establishing the modern land tax system; transforming the government functions.
基金the authors thank the help of professor Liang Xiao-guangZhang Bao-wen and Tung Chen-ho of our Institute
文摘Using acridine dyes as sensitizers,the photoisomerization of three norbornadiene derivatives was investigated.The valence isomerization of nor- bornadiene derivatives(Ⅰ_a,Ⅰ_b,Ⅰ_c)gave their corresponding isomers of quadri- cyclane(Ⅱ_a,Ⅱ_b,Ⅱ_c)operating with relatively high efficiency in an electron transfer mode.Their quantum yields of isomerization were determined and the reaction mechanism was discussed.
文摘Involuntary resettlenment caused by project construction is a difficult problem over world. In the past, therestoration of livelihoods in the event of involuntary resettlementhas been based purely on providing compensation to those who are displaced. Evidence has shown that compensation-based involuntary resettlement can not realize the objective of restoring and improving resettlers＇ living standard. With a view to improve this outcome, the concept of Resettlement with Development （RwD） was envisaged and is now generally heralded as the means to mitigate catastrophic failures of the past. However, few developing countries have included the concept of RwD into th, ational policies and China is one of them. The Chinese government has taken resettlement as an opportunity to help resettlers restore and improve their living standards and develop economy in reservoir areas by implementing RwD olicy including giving compensation and subsidies at early stage and offering production assistance at late stage, citing up reservoir construction fund, initiating partnership programs and preferential policy as well as enhanc infrastruture construction. The preliminary experience from the TGP resettlement has verified that the transformation from compensation-based resettlement to RwD is a right policy, choice. Meanwhile. because ofthe changing political environment and the complexity of involuntary resettlement there is still room for china to improve its RwD policy.
文摘In recent years, with the continuous progress of science and technology, the development of information technology has also begun to change. The popularity of the application of modern information technology in the field of education is very high. College students can obtain the knowledge and content they need from the network. Teachers are no longer the only source of information for students, which promotes the improvement of students academic performance and cultivates students autonomous learning ability. As a university teacher, the author discusses how to motivate college students autonomous learning in the process of virtual project-based practical teaching, hoping that this paper can provide a certain direction for the future development of university education and guide college students to cultivate their autonomous learning ability.
基金financial support from the National Natural Science Foundation of China(Nos.22173103,52063008)the Academic Talent Plan of Guizhou Normal University(No.Qian Shi Xin Miao[2021]27)the Fundamental Research Funds for the Central Universities and Beijing National Laboratory for Molecular Sciences(BNLMS2023014).
文摘Cross-coupling reactions between aryl halides and thiolates or selenolates typically require transition metals,photocatalysts,strong bases,or/and malodorous thiols/selenols,with various mechanisms proposed.This study aims to leverage a new application of neutral ChB to address these challenges and enable a very simple photoinduced cross-electrophile C—S/Se coupling using readily available chalcogen electrophiles.Mechanistic investigations have revealed the important role of neutral ChB in facilitating single electron transfer processes,thereby enabling the generation of thiolates/selenolates from stable chalcogen electrophiles andα-aminoalkyl radicals,which possess the capability to abstract halogen atoms from aryl iodides.Moreover,the study provided support for the radical nucleophilic substitution mechanism.
基金the National Natural Science Foundation of China(Nos.31672303 to C.Y.and 31772453 to W.L.)the current laws of China.Fieldwork was carried out under permission from Zhalong National Nature Reserve,P.R.China.
文摘Egg recognition is a variable but common anti-parasitism defense among different species of birds with brood parasites.In contrast,nestling recognition is rare.Very few studies have found nestling recognition in brood parasite hosts and determined the rejection mechanism behind this behavior.Hosts may use the number of hatchling downfeathers to reject parasite nestlings.We tested whether hatchling down-feathers is a visual cue for the red-rumped swallow,a host that can recognize and reject parasite nestlings.Our results indicated that red-rumped swallows do not recognize foreign nestlings based on hatchling down-feathers.The closed nest structure and hatchling morph may explain the absence of such a mechanism.None of the rejection mechanisms found in previous studies could explain the nestling recognition in swallows.Olfactory cues,tactile cues,or other visual cues,except for single nestling or hatchling down-feathers,may provide nestling recognition in red-rumped swallows.More study is needed to evaluate these possibilities.
基金supported by the funding of National Natural Science Foundation of China (No. 81770209).
文摘Sterile α motif and histidine/aspartic acid domain containing protein 1 (SAMHD1) is a deoxynucleoside triphosphate (dNTPs) triphosphohydrolase that can hydrolyze dNTPs into deoxynucleosides and triphosphates to keep the balance of the intracellular dNTPs pool. Moreover, it has been reported that SAMHD1 plays a role in regulating cell proliferation and the cell cycle, maintaining genome stability and inhibiting innate immune responses. SAMHD1 activity is regulated by phosphorylation, oxidation, SUMOylation, and O-GlcNAcylation. SAMHD1 mutations have been reported to cause diseases, including chronic lymphocytic leukemia and mantle cell lymphoma. SAMHD1 expression in acute myeloid leukemia predicts inferior prognosis. Recently, it has been revealed that SAMHD1 mediates the resistance to anti-cancer drugs. This review will focus on SAMHD1 function and regulation, the association between SAMHD1 and hematological malignancies and will provide updated information on SAMHD1 mediating resistance to nucleoside analogue antimetabolites, topoisomerase inhibitors, platinum-derived agents and DNA hypomethylating agents. Furthermore, histone deacetylase inhibitors and tyrosine kinase inhibitors indirectly increase anti-cancer drug resistance by increasing SAMDH1 activity. We herein highlight the importance of the development of novel agents targeting SAMHD1 to overcome treatment resistance of hematological malignancies, which would be an opportunity to improve the outcome of patients with refractory hematological malignancies.
