BACKGROUND: There are few data on blood group(BG) types and types of pancreatic cancers. The aims of this study were to study BG types and BG-antigens in pancreatic intraductal papillary mucinous neoplasms(IPMNs). MET...BACKGROUND: There are few data on blood group(BG) types and types of pancreatic cancers. The aims of this study were to study BG types and BG-antigens in pancreatic intraductal papillary mucinous neoplasms(IPMNs). METHODS: BG type and tumor BG-antigen(glycoprotein) expression(studied by immunohistochemistry on tissue microarrays) were analyzed with regard to characteristics of 101 surgically resected pancreatic IPMNs. RESULTS: Non-O BG type predicted invasive carcinoma independently from high serum CA19-9 and male gender. BG type A was observed more frequently in women than in men. Chronic pancreatitis was more frequently seen in patients with BG type B or AB. Aberrant tumor expression(with regard to BG type) of loss of A antigen expression type occurred in 15.0% of IPMNs and of loss of B antigen expression type in 62.5% of IPMNs. Intraneoplasm BG-antigen expression was not related to dysplasia grade or invasion. CONCLUSION: The results of the study suggest that in pancreatic IPMN, non-O BG type predicted invasive carcinoma, whereas for intratumor BG-antigen expression no specific patterns were detected with regard to the progression of glandular epithelial dysplasia or invasion.展开更多
Motivated by the idea of M. Ledoux who brings out the connection between Sobolev embeddings and heat kernel bounds, we prove an analogous result for Kohn’s sub-Laplacian on the Heisenberg type groups. The main result...Motivated by the idea of M. Ledoux who brings out the connection between Sobolev embeddings and heat kernel bounds, we prove an analogous result for Kohn’s sub-Laplacian on the Heisenberg type groups. The main result includes features of an inequality of either Sobolev or Galiardo-Nirenberg type.展开更多
1 Introduction Sareke glutenite-type copper deposit is the large size copper deposit discovered in recent years,and it is located Sarekebayi intracontinental pull-apart basin in the western margin of the Tarim basin.C...1 Introduction Sareke glutenite-type copper deposit is the large size copper deposit discovered in recent years,and it is located Sarekebayi intracontinental pull-apart basin in the western margin of the Tarim basin.Conglomerate of展开更多
Let △ be full Laplacian on H-type group G. Then for every compact set D Ga local estimate of the Schrodinger maximal operator holds, that is,∫D^sup0〈t〈1｜e^it△f（x）｜^2dx≤｜｜f｜｜^2H^s,s〉1/2We also show that ...Let △ be full Laplacian on H-type group G. Then for every compact set D Ga local estimate of the Schrodinger maximal operator holds, that is,∫D^sup0〈t〈1｜e^it△f（x）｜^2dx≤｜｜f｜｜^2H^s,s〉1/2We also show that the above inequality fails when s 〈 1/4.展开更多
This article obtains an explicit expression of the heat kernels on H-type groups and then follow the estimate of heat kernels to deduce the Hardy＇s uncertainty principle on the nilpotent Lie groups.
AIM:To study frequency of blood groups,prevalence of sickle-cell anemia trait and glucose-6-phosphate dehydrogenase deficiency(G6PD),among consanguineous Yansi tribe.METHODS:A total of 525 blood samples were collected...AIM:To study frequency of blood groups,prevalence of sickle-cell anemia trait and glucose-6-phosphate dehydrogenase deficiency(G6PD),among consanguineous Yansi tribe.METHODS:A total of 525 blood samples were collected,of which 256 among the Yansi population,and269 for the unrelated control group in the Bandunduprovince of Democratic Republic of Congo.Blood group antigens were determined in the following systems:ABO,Rh,Kell,Duffy,Kidd and MNS.Blood grouping and extended phenotype tests were performed according to standard immunohematological procedures.Spot tests and tandem mass spectrometry were used respectively for the assessment of G6PD and sickle-cell anemia trait.RESULTS:The frequency of ABO phenotypes conformed to the following order O>A>B>AB with notably 62.5%,23.8%,12.1%and 1.6%for the Yansi,and 54.6%,27.5%,14.1%and 3.7%for the unrelated control group,respectively(P=0.19).As for the Rh phenotypes,the most frequent were cc D.ee,cc D.Ee,Cc D.ee,corresponding to 71.5%,12.1%and 12.1%for the Yansi,and 70.6%,15.6%and 8.2%,for the unrelated control group(P=0.27).The frequency of MN and Ss phenotypes were statistically different between groups(P=0.0021 and P=0.0006).G6PD was observed in 11.3%of subjects in the Yansi group,and in 12.4%of controls(P=0.74).The sickle-cell anemia trait was present in 22.4%of Yansi subjects and 17.8%in the control group(P=0.24).Miscarriages and deaths in young age were more common among Yansi people.CONCLUSION:This study shows a significant difference in MNS blood group distribution between the Yansi tribe and a control population.The distribution of other blood groups and the prevalence of hemoglobinopathies did not differ in the Yansi tribe.展开更多
The Chinese mainland is divided into some tectonic blocks by nearly NE- and EW-orientated faults. Meanwhile strong earthquakes in the Chinese mainland usually cluster in time and space. We call earthquakes in groups. ...The Chinese mainland is divided into some tectonic blocks by nearly NE- and EW-orientated faults. Meanwhile strong earthquakes in the Chinese mainland usually cluster in time and space. We call earthquakes in groups. Tectonic blocks separated by faults and earthquakes in groups are prominent features of the tectonics of the Chi-nese mainland. Correlation between movement of tectonic blocks and groups of earthquakes is discussed in this paper. The results show that earthquakes in groups often occurred at one or several block boundary faults. The released elastic strain energy is built up in the same periods and around blocks. It means that strong earthquakes in groups are mainly caused by movement of blocks. Four types of block movement are identified based ongroup earthquakes: movement along a single boundary of a block (or a combined blocks), movement of a single block, movement of multi-blocks, and movement in block interiors. If we consider distribution of all strong earthquakes occurred in the Chinese mainland, the movement along a single boundary of a block is more popular one inducing strong earthquakes. But if we only consider earthquakes in groups rather than single earthquakesthe movement of a block dominates among four modes. Statistics with respect to group earthquakes show that the Taihangshan mountain and the North China block are much active in the eastern part of Chinese mainland, and in western part of Chinese mainland the active blocks are Sichuan-Yunnan and the Kunlun-Songpan ones.展开更多
In this work, we prove the existence and uniqueness of the solution of the generalized Schrödinger type homogeneous model in the periodic distributional space P’. Furthermore, we prove that the solution depends ...In this work, we prove the existence and uniqueness of the solution of the generalized Schrödinger type homogeneous model in the periodic distributional space P’. Furthermore, we prove that the solution depends continuously respect to the initial data in P’. Introducing a family of weakly continuous operators, we prove that this family is a group of operators in P’. Then, with this family of operators, we get a fine version of the existence and dependency continuous theorem obtained. Finally, we give some remarks derived from this study.展开更多
目的:对部分D表型孕妇进行免疫血清学和RHD基因型分析。方法:采用常规血型血清学方法鉴定孕妇RhD血型,并进行血型特异性抗体筛查和鉴定;采用序列特异性引物聚合酶链反应(polymerase chain reactionsequence specific primer,PCR-SSP)鉴...目的:对部分D表型孕妇进行免疫血清学和RHD基因型分析。方法:采用常规血型血清学方法鉴定孕妇RhD血型,并进行血型特异性抗体筛查和鉴定;采用序列特异性引物聚合酶链反应(polymerase chain reactionsequence specific primer,PCR-SSP)鉴定孕妇RHD基因型;采用多重连接依赖的探针扩增技术(multiplex ligationdependent probe amplification,MLPA)对孕妇及其配偶和女儿的RhD血型抗原进行基因分型及遗传分析。结果:该孕妇血清中检测出IgG抗-D,其抗体效价为1∶8。PCR-SSP结果显示,该孕妇RHD基因第3-6外显子缺失,经鉴定该孕妇RHD基因型为DVI type 3型。MLPA分析显示,该孕妇只有1条RHD等位基因,且缺失3-6外显子,其基因型为CDVIe/cde,其配偶为CDe/CDe纯合子基因型,女儿为CDe/CDVIe基因型。结论:准确的RhD血型鉴定对制定安全有效的临床输血策略和对育龄妇女采取恰当措施及预防新生儿溶血病具有重要意义。展开更多
The segment erector is a key part of the shield machines for tunnel engineering. The available segment erectors are all of serial configuration which is suffering from the problems of low rigidity and accumulative mot...The segment erector is a key part of the shield machines for tunnel engineering. The available segment erectors are all of serial configuration which is suffering from the problems of low rigidity and accumulative motion errors. The current research mainly focuses on improving assembly accuracy and control performance of serial segment erectors. An innovative design method is proposed featuring motion group-decoupling, based on which a new type of segment erector is developed and investigated. Firstly, the segment installation manipulation is analyzed and decomposed into three motion groups that are decoupled. Then the type synthesis for the 4-DOF motion group is performed based on the general function（GF） set theory and a new configuration of （1T？1R？1PS3UPS） is attained according to the segment manipulation requirements. Consequently, the kinematic models are built and the reducibility and accuracy are analyzed. The dexterity is verified though numerical simulation and no singular points appear in the workspace. Finally, a positioning experiment is carried out by using the prototype developed in the lab that demonstrates a 13.1% improvement of positioning accuracy and the feasibility of the new segment erector. The presented group-decoupling design method is able to invent new type of hybrid segment erectors that avoid the accumulative motion error of erecting.展开更多
Based on Lie group theory and the integration of configuration, a class of 3T2 R(T denotes translation and R denotes rotation) parallel mechanisms with large output rotational angles is synthesized through a five degr...Based on Lie group theory and the integration of configuration, a class of 3T2 R(T denotes translation and R denotes rotation) parallel mechanisms with large output rotational angles is synthesized through a five degree of freedom single limb evolving into two five degree of freedom limbs and constraint coupling of each kinematics chain. A kind of 3T2 R parallel mechanisms with large rotational angles was selected from type synthesis of 3T2 R parallel mechanisms, inverse kinematics and velocity Jacobian matrix of the parallel mechanism are established. The performance indices including workspace, rotational capacity, singularity and dexterity of the parallel mechanism are analyzed. The results show that the parallel mechanism has not only large output rotational angles but also better dexterity.展开更多
The rhyolites in the upper Lüliang Group of Shanxi, China, are Paleoproterozoic weakly alkaline volcanic rocks. They are characterized by high SiO\-2, Na\-2O+K\-2O, Zr, Nb, Ga, Y and REE contents and large FeO\+*...The rhyolites in the upper Lüliang Group of Shanxi, China, are Paleoproterozoic weakly alkaline volcanic rocks. They are characterized by high SiO\-2, Na\-2O+K\-2O, Zr, Nb, Ga, Y and REE contents and large FeO\+*/MgO, Rb/Sr and Ga/Al ratios, and low CaO, Sr and Eu contents, and share much in common with the A type granitic rocks. They erupted in the rift setting at the continental margin. Chemical features and isotope data, as well as high Nd and low initial Sr ratios, suggest that the original granitic magma was derived from partial melting of Late Archean metamorphic rocks in the lower crust due to the influence of basaltic magma and hot fluid in response to rifting. The A type rhyolites were finally formed after the fractional crystallization of the dominant mineral feldspar.展开更多
We call a group A-simple,if it has no non-trivial normal abelian subgroup.We will present finiteness results in controlled topology via geometry on manifolds whose fundamental groups are A-simple.
Preyssler-type heteropoly acid is introduced as a new,mild and efficient catalyst for protection of a variety of carbonyl compounds with 1,3-propane dithiol.
Poly（3-alkyl）pyrroles containing phosphonic acid groups with different alkyl segment lengths were chemical synthesized and the properties were measured by FTIR and UV-Vis spectroscopy. FTIR and UV-Vis results showed...Poly（3-alkyl）pyrroles containing phosphonic acid groups with different alkyl segment lengths were chemical synthesized and the properties were measured by FTIR and UV-Vis spectroscopy. FTIR and UV-Vis results showed that the synthesized polymers were in a low doping level through chemical polymerization. By spin-coating on the surface of substrates, the polymer can be used as a humidity sensor. The change of DC electric current of the polypyrroles varies with the chain length of the alkyl substituents. The capacitance increases with the increase of the humidity and resistance decreases with the increase of humidity. This result is different from that ofpolypyrrole without alkyl substituents due to the influence of the phosphonic acid group. The sensor showed the resistive-type at high relative humidity, and the capacitive- type at the low relative humidity. The sensor exhibited very fast response to the change of environment humidity.展开更多
Finding damage inside pipes is important for the inspection of complex pipes used in nuclear power plants and chemical plants. A number of studies have investigated the mechanisms of an actuator with an electric cable...Finding damage inside pipes is important for the inspection of complex pipes used in nuclear power plants and chemical plants. A number of studies have investigated the mechanisms of an actuator with an electric cable to provide locomotion through various devices in complex pipes. An in-pipe robot capable of movement in narrow complex pipes has not yet been developed. In the present paper, we propose a globular magnetic actuator group that exhibits a very high thrust force and is capable of free reversible motion in complex pipes. Two actuators of the same size and characteristics are coupled by the magnetic connection method, which generates almost no mechanical loss. The globular magnetic actuator group capable of reversible motion through elongation and contraction of eight shape-memory-alloy (SMA) coils was fabricated. Experimental results indicate that the prototype actuator group is able to climb at a rate of 29 mm/s in a straight pipe while pulling a load mass of 48 g. In addition, the average speeds for two patterns of movement in a complex pipe with several curved sections and step sections were measured. The prototype actuator group is able to move in a complex pipe at an average speed of over 30 mm/s. This actuator group has several possible applications, including inspection using a micro-camera and pipe maintenance.展开更多
Clinical trials are usually long term studies and it seems impossible to reach all required subjects at the same time. Performing interim analyses and monitoring results may provide early termination of trial after ob...Clinical trials are usually long term studies and it seems impossible to reach all required subjects at the same time. Performing interim analyses and monitoring results may provide early termination of trial after obtaining significant results. The aim of this study is comparing group sequential tests in respect to advantage of sample size reduction and early termination. In this study, 4 test types used in group sequential designs were compared with fixed sample size design test and each other. Comparisons were done according to two-sided tests for comparing two treatments. In this sense, 1080 models were performed. In models, 2 different Type I errors, 2 different powers, 5 different analysis groups, 6 different effect sizes and 9 different variances selections were considered. All test types increased the maximum sample size in different manner, compared with fixed sample size design. Each test had different critical values to reject H0 hypothesis, at the same type I error rate and number of analyses conditions. Selection of test type used in group sequential designs depends on a few characteristics, as reducing sample size, early termination and detecting minimal effect size. Test performance is highly related with selected Type I error rate, power and number of analyses. In addition to these statistical characteristics, researchers should decide test type with respect to other trial conditions as the issue of trial, reaching subjects easy or not and importance of early termination.展开更多
We estimate the influenza force according to the virus type in the USA (United States of America) for the season 2010/11 to 2019/20. For these we use the data available from CDC (Centers for Disease Control and Preven...We estimate the influenza force according to the virus type in the USA (United States of America) for the season 2010/11 to 2019/20. For these we use the data available from CDC (Centers for Disease Control and Prevention) related to Public Health Laboratory Virologic Age Surveillance and The Burden Estimates presented by CDC yearly.展开更多
Three novel redox-active percec-type dendrons were synthesized by mucleophilic substitution reaction of 11-bromoundecyl ferrocene and substituted benzoate.All the resultant ferrocenyl-modified dendrons were confirmed ...Three novel redox-active percec-type dendrons were synthesized by mucleophilic substitution reaction of 11-bromoundecyl ferrocene and substituted benzoate.All the resultant ferrocenyl-modified dendrons were confirmed through FT-IR,NMR,and elemental analysis,etc.Furthermore,the thermal properties and electrochemical behavior of these dendrons were monitored with thermogravimetry analysis（TG）,differential scanning calorimetry（DSC）,polarized optical microscope（POM）,and cyclic voltammetry（CV）. Abound phase behavior and reversible electrochemical redox reaction process in the DMF solution of these dendrons was observed.展开更多
In this paper, we investigate Kazhdan’s relative Property (T) for pairs , where is a topological group and is any subset of . We show that the pair has Property (FH) and every function conditionally of negative type ...In this paper, we investigate Kazhdan’s relative Property (T) for pairs , where is a topological group and is any subset of . We show that the pair has Property (FH) and every function conditionally of negative type on is X-bounded if the pair has relative Property (T). We also prove that has Property (T) whenis a s -compact locally compact group generated by its subgroups and the pair has relative Property (T) for all .展开更多
文摘BACKGROUND: There are few data on blood group(BG) types and types of pancreatic cancers. The aims of this study were to study BG types and BG-antigens in pancreatic intraductal papillary mucinous neoplasms(IPMNs). METHODS: BG type and tumor BG-antigen(glycoprotein) expression(studied by immunohistochemistry on tissue microarrays) were analyzed with regard to characteristics of 101 surgically resected pancreatic IPMNs. RESULTS: Non-O BG type predicted invasive carcinoma independently from high serum CA19-9 and male gender. BG type A was observed more frequently in women than in men. Chronic pancreatitis was more frequently seen in patients with BG type B or AB. Aberrant tumor expression(with regard to BG type) of loss of A antigen expression type occurred in 15.0% of IPMNs and of loss of B antigen expression type in 62.5% of IPMNs. Intraneoplasm BG-antigen expression was not related to dysplasia grade or invasion. CONCLUSION: The results of the study suggest that in pancreatic IPMN, non-O BG type predicted invasive carcinoma, whereas for intratumor BG-antigen expression no specific patterns were detected with regard to the progression of glandular epithelial dysplasia or invasion.
基金supported by National Science Foundation of China (10771175)
文摘Motivated by the idea of M. Ledoux who brings out the connection between Sobolev embeddings and heat kernel bounds, we prove an analogous result for Kohn’s sub-Laplacian on the Heisenberg type groups. The main result includes features of an inequality of either Sobolev or Galiardo-Nirenberg type.
基金supported by the metallogenic regularities and prediction of glutenite type Cu-Pb-Zn deposit in Tarim west margin(201511016-1)the special mapping techniques and its application demonstration in Sareke overall-exploration area in Xinjiang(12120114081501)
文摘1 Introduction Sareke glutenite-type copper deposit is the large size copper deposit discovered in recent years,and it is located Sarekebayi intracontinental pull-apart basin in the western margin of the Tarim basin.Conglomerate of
基金supported by National Nature Science Foundation of China(11371036)
文摘Let △ be full Laplacian on H-type group G. Then for every compact set D Ga local estimate of the Schrodinger maximal operator holds, that is,∫D^sup0〈t〈1｜e^it△f（x）｜^2dx≤｜｜f｜｜^2H^s,s〉1/2We also show that the above inequality fails when s 〈 1/4.
基金supported by National Science Foundation of China (10571044)
文摘This article obtains an explicit expression of the heat kernels on H-type groups and then follow the estimate of heat kernels to deduce the Hardy＇s uncertainty principle on the nilpotent Lie groups.
文摘AIM:To study frequency of blood groups,prevalence of sickle-cell anemia trait and glucose-6-phosphate dehydrogenase deficiency(G6PD),among consanguineous Yansi tribe.METHODS:A total of 525 blood samples were collected,of which 256 among the Yansi population,and269 for the unrelated control group in the Bandunduprovince of Democratic Republic of Congo.Blood group antigens were determined in the following systems:ABO,Rh,Kell,Duffy,Kidd and MNS.Blood grouping and extended phenotype tests were performed according to standard immunohematological procedures.Spot tests and tandem mass spectrometry were used respectively for the assessment of G6PD and sickle-cell anemia trait.RESULTS:The frequency of ABO phenotypes conformed to the following order O>A>B>AB with notably 62.5%,23.8%,12.1%and 1.6%for the Yansi,and 54.6%,27.5%,14.1%and 3.7%for the unrelated control group,respectively(P=0.19).As for the Rh phenotypes,the most frequent were cc D.ee,cc D.Ee,Cc D.ee,corresponding to 71.5%,12.1%and 12.1%for the Yansi,and 70.6%,15.6%and 8.2%,for the unrelated control group(P=0.27).The frequency of MN and Ss phenotypes were statistically different between groups(P=0.0021 and P=0.0006).G6PD was observed in 11.3%of subjects in the Yansi group,and in 12.4%of controls(P=0.74).The sickle-cell anemia trait was present in 22.4%of Yansi subjects and 17.8%in the control group(P=0.24).Miscarriages and deaths in young age were more common among Yansi people.CONCLUSION:This study shows a significant difference in MNS blood group distribution between the Yansi tribe and a control population.The distribution of other blood groups and the prevalence of hemoglobinopathies did not differ in the Yansi tribe.
基金Foundation item: State Key Basic Research Planning Project (G199804070401).
文摘The Chinese mainland is divided into some tectonic blocks by nearly NE- and EW-orientated faults. Meanwhile strong earthquakes in the Chinese mainland usually cluster in time and space. We call earthquakes in groups. Tectonic blocks separated by faults and earthquakes in groups are prominent features of the tectonics of the Chi-nese mainland. Correlation between movement of tectonic blocks and groups of earthquakes is discussed in this paper. The results show that earthquakes in groups often occurred at one or several block boundary faults. The released elastic strain energy is built up in the same periods and around blocks. It means that strong earthquakes in groups are mainly caused by movement of blocks. Four types of block movement are identified based ongroup earthquakes: movement along a single boundary of a block (or a combined blocks), movement of a single block, movement of multi-blocks, and movement in block interiors. If we consider distribution of all strong earthquakes occurred in the Chinese mainland, the movement along a single boundary of a block is more popular one inducing strong earthquakes. But if we only consider earthquakes in groups rather than single earthquakesthe movement of a block dominates among four modes. Statistics with respect to group earthquakes show that the Taihangshan mountain and the North China block are much active in the eastern part of Chinese mainland, and in western part of Chinese mainland the active blocks are Sichuan-Yunnan and the Kunlun-Songpan ones.
文摘In this work, we prove the existence and uniqueness of the solution of the generalized Schrödinger type homogeneous model in the periodic distributional space P’. Furthermore, we prove that the solution depends continuously respect to the initial data in P’. Introducing a family of weakly continuous operators, we prove that this family is a group of operators in P’. Then, with this family of operators, we get a fine version of the existence and dependency continuous theorem obtained. Finally, we give some remarks derived from this study.
文摘目的:对部分D表型孕妇进行免疫血清学和RHD基因型分析。方法:采用常规血型血清学方法鉴定孕妇RhD血型,并进行血型特异性抗体筛查和鉴定;采用序列特异性引物聚合酶链反应(polymerase chain reactionsequence specific primer,PCR-SSP)鉴定孕妇RHD基因型;采用多重连接依赖的探针扩增技术(multiplex ligationdependent probe amplification,MLPA)对孕妇及其配偶和女儿的RhD血型抗原进行基因分型及遗传分析。结果:该孕妇血清中检测出IgG抗-D,其抗体效价为1∶8。PCR-SSP结果显示,该孕妇RHD基因第3-6外显子缺失,经鉴定该孕妇RHD基因型为DVI type 3型。MLPA分析显示,该孕妇只有1条RHD等位基因,且缺失3-6外显子,其基因型为CDVIe/cde,其配偶为CDe/CDe纯合子基因型,女儿为CDe/CDVIe基因型。结论:准确的RhD血型鉴定对制定安全有效的临床输血策略和对育龄妇女采取恰当措施及预防新生儿溶血病具有重要意义。
基金supported by National Natural Science Foundation of China(Grant No. 51275284)Program for New Century Excellent Talents in University of China(Grant No. NCET-10-0567)the Research Fund of State Key Lab of Mechanical Systems and Vibration(Grant No.MSV-ZD-2010-02)
文摘The segment erector is a key part of the shield machines for tunnel engineering. The available segment erectors are all of serial configuration which is suffering from the problems of low rigidity and accumulative motion errors. The current research mainly focuses on improving assembly accuracy and control performance of serial segment erectors. An innovative design method is proposed featuring motion group-decoupling, based on which a new type of segment erector is developed and investigated. Firstly, the segment installation manipulation is analyzed and decomposed into three motion groups that are decoupled. Then the type synthesis for the 4-DOF motion group is performed based on the general function（GF） set theory and a new configuration of （1T？1R？1PS3UPS） is attained according to the segment manipulation requirements. Consequently, the kinematic models are built and the reducibility and accuracy are analyzed. The dexterity is verified though numerical simulation and no singular points appear in the workspace. Finally, a positioning experiment is carried out by using the prototype developed in the lab that demonstrates a 13.1% improvement of positioning accuracy and the feasibility of the new segment erector. The presented group-decoupling design method is able to invent new type of hybrid segment erectors that avoid the accumulative motion error of erecting.
基金supported by Fundamental Research Funds for the Central Universities (No. 2018JBZ007)
文摘Based on Lie group theory and the integration of configuration, a class of 3T2 R(T denotes translation and R denotes rotation) parallel mechanisms with large output rotational angles is synthesized through a five degree of freedom single limb evolving into two five degree of freedom limbs and constraint coupling of each kinematics chain. A kind of 3T2 R parallel mechanisms with large rotational angles was selected from type synthesis of 3T2 R parallel mechanisms, inverse kinematics and velocity Jacobian matrix of the parallel mechanism are established. The performance indices including workspace, rotational capacity, singularity and dexterity of the parallel mechanism are analyzed. The results show that the parallel mechanism has not only large output rotational angles but also better dexterity.
文摘The rhyolites in the upper Lüliang Group of Shanxi, China, are Paleoproterozoic weakly alkaline volcanic rocks. They are characterized by high SiO\-2, Na\-2O+K\-2O, Zr, Nb, Ga, Y and REE contents and large FeO\+*/MgO, Rb/Sr and Ga/Al ratios, and low CaO, Sr and Eu contents, and share much in common with the A type granitic rocks. They erupted in the rift setting at the continental margin. Chemical features and isotope data, as well as high Nd and low initial Sr ratios, suggest that the original granitic magma was derived from partial melting of Late Archean metamorphic rocks in the lower crust due to the influence of basaltic magma and hot fluid in response to rifting. The A type rhyolites were finally formed after the fractional crystallization of the dominant mineral feldspar.
基金the author Rong at Capital Normal University,which was partially supported by NSFC Grant 11821101,Beijing Natural Science Foundation Z19003,and a research fund from Capital Normal University.
文摘We call a group A-simple,if it has no non-trivial normal abelian subgroup.We will present finiteness results in controlled topology via geometry on manifolds whose fundamental groups are A-simple.
文摘Preyssler-type heteropoly acid is introduced as a new,mild and efficient catalyst for protection of a variety of carbonyl compounds with 1,3-propane dithiol.
基金supported by the Fundamental Research Funds for the Central Universities,China(No.GK 200902008)
文摘Poly（3-alkyl）pyrroles containing phosphonic acid groups with different alkyl segment lengths were chemical synthesized and the properties were measured by FTIR and UV-Vis spectroscopy. FTIR and UV-Vis results showed that the synthesized polymers were in a low doping level through chemical polymerization. By spin-coating on the surface of substrates, the polymer can be used as a humidity sensor. The change of DC electric current of the polypyrroles varies with the chain length of the alkyl substituents. The capacitance increases with the increase of the humidity and resistance decreases with the increase of humidity. This result is different from that ofpolypyrrole without alkyl substituents due to the influence of the phosphonic acid group. The sensor showed the resistive-type at high relative humidity, and the capacitive- type at the low relative humidity. The sensor exhibited very fast response to the change of environment humidity.
文摘Finding damage inside pipes is important for the inspection of complex pipes used in nuclear power plants and chemical plants. A number of studies have investigated the mechanisms of an actuator with an electric cable to provide locomotion through various devices in complex pipes. An in-pipe robot capable of movement in narrow complex pipes has not yet been developed. In the present paper, we propose a globular magnetic actuator group that exhibits a very high thrust force and is capable of free reversible motion in complex pipes. Two actuators of the same size and characteristics are coupled by the magnetic connection method, which generates almost no mechanical loss. The globular magnetic actuator group capable of reversible motion through elongation and contraction of eight shape-memory-alloy (SMA) coils was fabricated. Experimental results indicate that the prototype actuator group is able to climb at a rate of 29 mm/s in a straight pipe while pulling a load mass of 48 g. In addition, the average speeds for two patterns of movement in a complex pipe with several curved sections and step sections were measured. The prototype actuator group is able to move in a complex pipe at an average speed of over 30 mm/s. This actuator group has several possible applications, including inspection using a micro-camera and pipe maintenance.
文摘Clinical trials are usually long term studies and it seems impossible to reach all required subjects at the same time. Performing interim analyses and monitoring results may provide early termination of trial after obtaining significant results. The aim of this study is comparing group sequential tests in respect to advantage of sample size reduction and early termination. In this study, 4 test types used in group sequential designs were compared with fixed sample size design test and each other. Comparisons were done according to two-sided tests for comparing two treatments. In this sense, 1080 models were performed. In models, 2 different Type I errors, 2 different powers, 5 different analysis groups, 6 different effect sizes and 9 different variances selections were considered. All test types increased the maximum sample size in different manner, compared with fixed sample size design. Each test had different critical values to reject H0 hypothesis, at the same type I error rate and number of analyses conditions. Selection of test type used in group sequential designs depends on a few characteristics, as reducing sample size, early termination and detecting minimal effect size. Test performance is highly related with selected Type I error rate, power and number of analyses. In addition to these statistical characteristics, researchers should decide test type with respect to other trial conditions as the issue of trial, reaching subjects easy or not and importance of early termination.
文摘We estimate the influenza force according to the virus type in the USA (United States of America) for the season 2010/11 to 2019/20. For these we use the data available from CDC (Centers for Disease Control and Prevention) related to Public Health Laboratory Virologic Age Surveillance and The Burden Estimates presented by CDC yearly.
基金The financial support from the NSFC(No.50873037)China Postdoctoral Science Foundation(No.20100470908, 201104349)the NSF of Guangdong Province(No.10451064101005118) is gratefully acknowledged
文摘Three novel redox-active percec-type dendrons were synthesized by mucleophilic substitution reaction of 11-bromoundecyl ferrocene and substituted benzoate.All the resultant ferrocenyl-modified dendrons were confirmed through FT-IR,NMR,and elemental analysis,etc.Furthermore,the thermal properties and electrochemical behavior of these dendrons were monitored with thermogravimetry analysis（TG）,differential scanning calorimetry（DSC）,polarized optical microscope（POM）,and cyclic voltammetry（CV）. Abound phase behavior and reversible electrochemical redox reaction process in the DMF solution of these dendrons was observed.
文摘In this paper, we investigate Kazhdan’s relative Property (T) for pairs , where is a topological group and is any subset of . We show that the pair has Property (FH) and every function conditionally of negative type on is X-bounded if the pair has relative Property (T). We also prove that has Property (T) whenis a s -compact locally compact group generated by its subgroups and the pair has relative Property (T) for all .
