Free quenching of automotive leaf springs is a new technology that has gradually started to be applied in the industry in China in recent years.Only a few manufacturers are applying it in the industry.Through more tha...Free quenching of automotive leaf springs is a new technology that has gradually started to be applied in the industry in China in recent years.Only a few manufacturers are applying it in the industry.Through more than half a year of on-site practice,the changes in the hot forming of spring plates before free quenching have been explored,and finally a heat treatment process that meets the production requirements of our company has been developed,achieving normal production.展开更多
Objective] The research aimed to study the characteristics of nitrogen and phosphorus pollution of 30 natural outcrop springs in Wudalianchi, which provides a theoretical basis for the sustainable development and util...Objective] The research aimed to study the characteristics of nitrogen and phosphorus pollution of 30 natural outcrop springs in Wudalianchi, which provides a theoretical basis for the sustainable development and utilization and protection of Wudalianchi natural mineral resources. [Method] Choosing the 30 natural outcrop spring representatives in different regions, samples were collected in low water period, normal water period, wet period respectively, and the content of nitrogen, phosphorus and other contaminants in the samples were determined. Besides, the pollution characteristics of nitrogen and phosphorus in Wudalianchi natural outcrop spring were analyzed. [Result] The 30 natural outcrop spring in Wudalianchi area were seriously polluted by nitrogen. Total nitrogen and nitrate nitrogen were the main forms of nitrogen pollution. The content of total phosphorus and ammonia nitrogen were low. [Conclusion] The natural outcrop spring is mainly caused by agricultural non-point source pollution.展开更多
The paper had introduced geographic causes and types of hot springs, illustrated its disease-treating function and displayed its great vitality and widespread development prospect as tourist resources. By taking Shawa...The paper had introduced geographic causes and types of hot springs, illustrated its disease-treating function and displayed its great vitality and widespread development prospect as tourist resources. By taking Shawan Hot Spring in Xinjiang for example, the paper had analyzed its natural condition, hot springs and tourist economic development. And then, quantitative and qualitative analysis had been conducted on the quality of water environment resources in the research area. It had analyzed reasons for degeneration of water environment and studied exploitation and sustainable development of hot springs. It was considered that environment especially water environment quality had decreased since hot spring tourism development. In order to achieve sustainable development of hot springs and promotion of local tourism, it must be guided by environment treatment, and some strategies for sustainable development of hot springs had been proposed.展开更多
The Tengchong geothermal area,an active tectonic region with frequent earthquakes,is located in Yunnan Province of southwestern China.This area contains abundant active hot springs, which often display high metal conc...The Tengchong geothermal area,an active tectonic region with frequent earthquakes,is located in Yunnan Province of southwestern China.This area contains abundant active hot springs, which often display high metal concentrations and obvious mineralization phenomena.At 19:19 on 9 July 2009,an earthquake occurred in Yao'an,Chuxiong,Yunnan Province,which is 300 km to the northeast of the Tengchong geothermal area.We sampled water in the hot springs in the Tengchong area from 4 July to 9 July 2009 and from 10 July to 15 July 2009 to study the changes of elemental concentrations before and after the earthquake and discuss the influence of the earthquake on the mineralization of the hot springs.The concentrations of most trace elements increased slightly,but the concentration of REE(rare earth elements) decreased by 50%after the earthquake in the hot springs around a NS-trending fault.The elemental concentrations remained unchanged in Longtan and Suanshuigou,which are related to an inactive crater.The elemental concentrations in other springs controlled by superficial and small-scale faults decreased after the earthquake.The earthquake can stimulate the activity of deep faults and magma chambers,as is responsible for the increase of metal concentrations in the hot springs along the NS-trending deep fault;whereas it can decrease the porosity of permeable rocks,resulting in the decline of the flux of ore-bearing fluids and the corresponding mineralization in the hot springs related to superficial faults.展开更多
A stranded wires helical spring is formed of a multilayer and coaxial strand of several wires twisted together with the same direction of spiral. Compared with the conventional single wire spring, the stranded wires h...A stranded wires helical spring is formed of a multilayer and coaxial strand of several wires twisted together with the same direction of spiral. Compared with the conventional single wire spring, the stranded wires helical spring has the notable predominance in strength, damping and vibration reduction, which is usually used in aircraft engines, automatic weapons, etc. However, due to its complicated structure, the precise computation of its strength and rigidity need be a correct mathematical model, which then will be imported to finite element analysis software for solutions. Equations on solving geometric parameters, such as external diameters of strands and screw pitches of wires, are put forward in the paper. It also proposes a novel methodology on solving geometric parameters and establishing entity models of the stranded wires helical spring, which provides foundation of computing mechanical parameters by FEA. Then mathematical models on the centre line of the strand and the surface curve of each wire, after closing two ends in a spring, are proposed. Finally, geometric parameters are solved in a case study, and a 3D entity model of a spring with 3 layers and 16 wires is established, which has validated the accuracy of the proposed methodology and the 3D entity mathematical model. The method provides a new way to design stranded wire helical spring.展开更多
The dynamic behavior of the stranded wire helical spring is described by a modified Bouc-Wen model while the model parameters must be identified using an identification method and experimental data. Existing identific...The dynamic behavior of the stranded wire helical spring is described by a modified Bouc-Wen model while the model parameters must be identified using an identification method and experimental data. Existing identification methods usually relies either solely nonlinear iterative algorithms or manually trial and error. Therefore, the identification process can be rather time consuming and effort taking. As a result, these methods are not ideal for engineering applications. To come up with a more practical method, a three-stage identification method is proposed. Periodic loading and identification simulations are carried out to verify the effectiveness of the proposed method. Noises are added to the simulated data to test the performance of the proposed method when dealing with noise contaminated data. The simulation results indicate that the proposed method is able to give satisfying results when the noise levels are set to be 0.01, 0.03, 0.05 and 0.07. In addition, the proposed method is also applied to experimental data and compared with an existing method. The experimental data is acquired through a periodic loading test. The experiment results suggest that the proposed method features better accuracy compared with the existing method. An effective approach is proposed for identifying the model parameters of the stranded wire helical spring.展开更多
The microbial diversity in Wuli Area, Qinghai-Tibetan Plateau was investigated using 16S rRNA gene phylogenetic analyses. A total of 117 bacterial and 66 archaeal 16S rRNA gene clones were obtained from the Wuli cold ...The microbial diversity in Wuli Area, Qinghai-Tibetan Plateau was investigated using 16S rRNA gene phylogenetic analyses. A total of 117 bacterial and 66 archaeal 16S rRNA gene clones were obtained from the Wuli cold springs, The bacterial clones could be classified into Proteobacteria, Acid- obacteria, Deinococci, Sphingobacteria, Flavobacteria, Nitrospirae, Actinobacteria, Gemmatimona- detes, and unclassified-bacteria; and the archaeal clones could be classified into Crenarchaeota and Thaumarchaeota. Among the major groups, Proteobacteria and Crenarchaeota were dominant in the bacterial and archaeal 16S rRNA gene clone libraries, respectively. The clone sequences obtained in Wuli cold springs were closely related to those from cold habitats, such as snow/ice/soils on high mountains or at high latitude. Especially, the microbial community composition of Wuli Area was more similar to that in Tibetan glaciers than cold environments of other locations. The data presented in this study have impli- cations for a better understanding of microbial diversity in cold springs on the Qinghai-Tibetan Plateau.展开更多
The free vibration analysis of cylindrical helical springs is carried out by means of an analytical study. In the governing equations of the motion of the springs, all displacement functions are defined at the centroi...The free vibration analysis of cylindrical helical springs is carried out by means of an analytical study. In the governing equations of the motion of the springs, all displacement functions are defined at the centroid axis and also the effects of the rotational inertia, axial and shear deformations are included in the proposed model. Explicit analytical expressions which give the vibrating mode shapes are derived by rigorous application of the symbolic computing package MATHEMATICA and a process of searching is used to determine the exact natural frequencies. Numerical examples are provided for fixed-fixed boundary conditions. The free vibrational pa- rameters are chosen as the number of coils (n = 4- 14), the helix pitch angle (a = 5 - 30°) and as the ratio of the diameters of the cylinder and the wire (D/d = 4 - 18) in a wide range. Validation of the proposed model has been achieved through comparison with a finite element model using two-node standard beam elements and the results available in published literature, which in these cases indicates a very good correlation.展开更多
Based on their genesis, springs are commonly classified as depression spring, contact spring, overflow spring and fault spring, etc. In addition, a kind of springs, i.e., up-flow spring, can be found in the field. An ...Based on their genesis, springs are commonly classified as depression spring, contact spring, overflow spring and fault spring, etc. In addition, a kind of springs, i.e., up-flow spring, can be found in the field. An aquifer is overlain by poorly-permeable unconsolidated sediments or relatively impervious formations. If the hydraulic head of the aquifer is higher than the land surface, groundwater may flow up to the ground surface through the local portion of the overlying aquicludes where the permeability is relatively good, and emerges as an up-flow spring. The common characteristics of an up-flow spring are discussed and summarized in this paper, and some examples of the up-flow springs are also given. Up-flow springs can flow up through local permeable zones in the overlying aquicludes rather than permeable faults. Although they cannot be found as frequently as depression springs, contact springs, overflow springs and fault springs etc., yet up-flow springs may occur in the form of normal-temperature springs, hot springs and salt springs.展开更多
Microbial mats, mainly dominated by filamentous algae Calothrix and Oscillatoria, are well developed in Tibetan hot springs. A great number of fossil microorganisms, which existed as algae lamination in thermal deposi...Microbial mats, mainly dominated by filamentous algae Calothrix and Oscillatoria, are well developed in Tibetan hot springs. A great number of fossil microorganisms, which existed as algae lamination in thermal depositional cesium-bearing geyserite in this area, are identified as Calothrix and Oscillatoria through microexamination and culture experiments. These microbial mats show the ability to accumulate cesium from spring water to the extent of cesium concentration of 0.46-1.03% cell dry weight, 900 times higher than that in water, and capture large numbers of cesium-bearing opal grain. Silicon dioxide colloid in spring water replaces and fills with the organism and deposits on it to form algae laminated geyserite after dehydration and congelation. Cesium in the microbial mats and opal grain is then reserved in the geyserite. Eventually, cesium-bearing algae laminated geyserite is formed. Study on cesium distribution in geyserite also shows that cesium content in algae lamination, especially in heavily compacted algae lamination, is higher than in the opal layer. For geyserite with no algae lamination or other organism structure, which is generally formed in spring water with low silicon content, cesium accumulation and cesium-bearing opal grain assembled by the microbial mats are also indispensable. After the microbial mats accumulating cesium from spring water, silicon dioxide colloid poorly replaces and fills with the organism to form opal grain-bearing tremellose microbial mats. The shape and structure of the organisms are then destroyed, resulting in cesium-bearing geyserite with no algae lamination structure after dehydration and congelation. It is then concluded that microbial mats in the spring area contribute to the enrichment of cesium in the formation of cesium-bearing geyserite, and a biological genesis of the geyserite, besides of the physical and chemical genesis, is likely.展开更多
A new method is presented to describe and analyze the spatial compliance ofcoiled springs using screw theory. After an abbreviated description for the deformation of a beamelement using screw theory, the spatial compl...A new method is presented to describe and analyze the spatial compliance ofcoiled springs using screw theory. After an abbreviated description for the deformation of a beamelement using screw theory, the spatial compliance density for a beam element is derived based onthe fundamental material theory and reasonable assumptions, and the spatial compliance of the beamwith finite length is obtained by integral. The spatial compliance of coiled springs is furtheranalyzed using the spatial compliance density of the beam element. By calculating theeigencompliance and Ball's principle screws for the whole compliance of system, the complianceproperties varying with the basic physical parameters of the system are illustrated in detail. Thebasic ideas can be used for the design and application of the coiled springs and the other compliantmechanisms with spatial compliant beam element.展开更多
Isoprenoidal glycerol dialkyl glycerol tetraethers (iGDGTs) from the Gulu hot springs (23--83.6 ℃, pH 〉 7) and Yangbajing hot springs (80-128 ℃, pH 〉 7) were analyzed in order to investigate the distribution...Isoprenoidal glycerol dialkyl glycerol tetraethers (iGDGTs) from the Gulu hot springs (23--83.6 ℃, pH 〉 7) and Yangbajing hot springs (80-128 ℃, pH 〉 7) were analyzed in order to investigate the distribution of archaeal lipids among different hot springs in Tibet. A soil sample from Gulu was incubated at different temperatures and analyzed for changes in iGDGTs to help evaluate whether surrounding soil may contribute to the iGDGTs in hot springs. The sources of bacterial GDGTs (bGDGTs) in these hot springs were also investigated. The results revealed different profiles ofiGDGTs between Gulu and Yangbajing hot springs. Core iGDGTs and polar iGDGTs also presented different patterns in each hot spring. The PCA analysis showed that the structure of polar iGDGTs can be explained by three factors and suggested multiple sources of these compounds. Bivariate correlation analysis showed significant positive correlations between polar and core bGDGTs, suggesting the in situ production of bGDGTs in the hot springs. Furthermore, in the soil incubation experiment, temperature had the most significant influence on concentration of bGDGTs rather than iGDGTs, and polar bGDGTs had greater variability than core bGDGTs with changing temperature. Our results indicated that soil input had little influence on the composition of GDGTs in Tibetan hot springs.展开更多
文摘Free quenching of automotive leaf springs is a new technology that has gradually started to be applied in the industry in China in recent years.Only a few manufacturers are applying it in the industry.Through more than half a year of on-site practice,the changes in the hot forming of spring plates before free quenching have been explored,and finally a heat treatment process that meets the production requirements of our company has been developed,achieving normal production.
基金Supported by Basic Scientific Research Program of Heilongjiang Province~~
文摘Objective] The research aimed to study the characteristics of nitrogen and phosphorus pollution of 30 natural outcrop springs in Wudalianchi, which provides a theoretical basis for the sustainable development and utilization and protection of Wudalianchi natural mineral resources. [Method] Choosing the 30 natural outcrop spring representatives in different regions, samples were collected in low water period, normal water period, wet period respectively, and the content of nitrogen, phosphorus and other contaminants in the samples were determined. Besides, the pollution characteristics of nitrogen and phosphorus in Wudalianchi natural outcrop spring were analyzed. [Result] The 30 natural outcrop spring in Wudalianchi area were seriously polluted by nitrogen. Total nitrogen and nitrate nitrogen were the main forms of nitrogen pollution. The content of total phosphorus and ammonia nitrogen were low. [Conclusion] The natural outcrop spring is mainly caused by agricultural non-point source pollution.
基金Supported by Natural Science Foundation of China (40961008)~~
文摘The paper had introduced geographic causes and types of hot springs, illustrated its disease-treating function and displayed its great vitality and widespread development prospect as tourist resources. By taking Shawan Hot Spring in Xinjiang for example, the paper had analyzed its natural condition, hot springs and tourist economic development. And then, quantitative and qualitative analysis had been conducted on the quality of water environment resources in the research area. It had analyzed reasons for degeneration of water environment and studied exploitation and sustainable development of hot springs. It was considered that environment especially water environment quality had decreased since hot spring tourism development. In order to achieve sustainable development of hot springs and promotion of local tourism, it must be guided by environment treatment, and some strategies for sustainable development of hot springs had been proposed.
基金supported by the Major State Basic Research Development Program of the People's Republic of China(973 project)(No.2009CB421008)the 111 Project(No.B07011)+2 种基金the National Natural Science Foundation of China(No.40234051)the Program for Changjiang Scholars and Innovative Research Team in University(No.IRT0755)the Special Plans of Science and Technology of Land Resource Department(No. 20010103)
文摘The Tengchong geothermal area,an active tectonic region with frequent earthquakes,is located in Yunnan Province of southwestern China.This area contains abundant active hot springs, which often display high metal concentrations and obvious mineralization phenomena.At 19:19 on 9 July 2009,an earthquake occurred in Yao'an,Chuxiong,Yunnan Province,which is 300 km to the northeast of the Tengchong geothermal area.We sampled water in the hot springs in the Tengchong area from 4 July to 9 July 2009 and from 10 July to 15 July 2009 to study the changes of elemental concentrations before and after the earthquake and discuss the influence of the earthquake on the mineralization of the hot springs.The concentrations of most trace elements increased slightly,but the concentration of REE(rare earth elements) decreased by 50%after the earthquake in the hot springs around a NS-trending fault.The elemental concentrations remained unchanged in Longtan and Suanshuigou,which are related to an inactive crater.The elemental concentrations in other springs controlled by superficial and small-scale faults decreased after the earthquake.The earthquake can stimulate the activity of deep faults and magma chambers,as is responsible for the increase of metal concentrations in the hot springs along the NS-trending deep fault;whereas it can decrease the porosity of permeable rocks,resulting in the decline of the flux of ore-bearing fluids and the corresponding mineralization in the hot springs related to superficial faults.
基金supported by National Natural Science Foundation for Distinguished Young Scholar of China (Grant No. 50925518)National Natural Science Foundation of China (Grant No. 50775226)+1 种基金Key Project of Ministry of Education of China(Grant No. 109129)Chongqing Municipal Key Scientific and Technological Project of China (Grant No. CSTC2009AC3049)
文摘A stranded wires helical spring is formed of a multilayer and coaxial strand of several wires twisted together with the same direction of spiral. Compared with the conventional single wire spring, the stranded wires helical spring has the notable predominance in strength, damping and vibration reduction, which is usually used in aircraft engines, automatic weapons, etc. However, due to its complicated structure, the precise computation of its strength and rigidity need be a correct mathematical model, which then will be imported to finite element analysis software for solutions. Equations on solving geometric parameters, such as external diameters of strands and screw pitches of wires, are put forward in the paper. It also proposes a novel methodology on solving geometric parameters and establishing entity models of the stranded wires helical spring, which provides foundation of computing mechanical parameters by FEA. Then mathematical models on the centre line of the strand and the surface curve of each wire, after closing two ends in a spring, are proposed. Finally, geometric parameters are solved in a case study, and a 3D entity model of a spring with 3 layers and 16 wires is established, which has validated the accuracy of the proposed methodology and the 3D entity mathematical model. The method provides a new way to design stranded wire helical spring.
基金Supported by National Natural Science Foundation of China(Grant Nos.51375508,51375517)the Key Technologies R&D Program of China(Grant No.2012BAF12B09)the Program for Changjiang Scholars and Innovative Research Team in University of Ministry of Education of China(Grant No.IRT1196)
文摘The dynamic behavior of the stranded wire helical spring is described by a modified Bouc-Wen model while the model parameters must be identified using an identification method and experimental data. Existing identification methods usually relies either solely nonlinear iterative algorithms or manually trial and error. Therefore, the identification process can be rather time consuming and effort taking. As a result, these methods are not ideal for engineering applications. To come up with a more practical method, a three-stage identification method is proposed. Periodic loading and identification simulations are carried out to verify the effectiveness of the proposed method. Noises are added to the simulated data to test the performance of the proposed method when dealing with noise contaminated data. The simulation results indicate that the proposed method is able to give satisfying results when the noise levels are set to be 0.01, 0.03, 0.05 and 0.07. In addition, the proposed method is also applied to experimental data and compared with an existing method. The experimental data is acquired through a periodic loading test. The experiment results suggest that the proposed method features better accuracy compared with the existing method. An effective approach is proposed for identifying the model parameters of the stranded wire helical spring.
基金supported by grants from National Science Foundation of China(Grant Nos.41030211 and 41002123)the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Edncation Ministry,Research Fund for the Doctoral Program of Higher Education of China(Grant No. 20100022120009)+1 种基金the Fundamental Research Funds for the Central Universities(Grant Nos.2010ZY16 and 2011YXL03)the Teaching Laboratory Funds from China University of Geosciences,Beijing
文摘The microbial diversity in Wuli Area, Qinghai-Tibetan Plateau was investigated using 16S rRNA gene phylogenetic analyses. A total of 117 bacterial and 66 archaeal 16S rRNA gene clones were obtained from the Wuli cold springs, The bacterial clones could be classified into Proteobacteria, Acid- obacteria, Deinococci, Sphingobacteria, Flavobacteria, Nitrospirae, Actinobacteria, Gemmatimona- detes, and unclassified-bacteria; and the archaeal clones could be classified into Crenarchaeota and Thaumarchaeota. Among the major groups, Proteobacteria and Crenarchaeota were dominant in the bacterial and archaeal 16S rRNA gene clone libraries, respectively. The clone sequences obtained in Wuli cold springs were closely related to those from cold habitats, such as snow/ice/soils on high mountains or at high latitude. Especially, the microbial community composition of Wuli Area was more similar to that in Tibetan glaciers than cold environments of other locations. The data presented in this study have impli- cations for a better understanding of microbial diversity in cold springs on the Qinghai-Tibetan Plateau.
基金supported by the National Natural Science Foundation of China (No.10572105)the Shanghai Leading Academic Discipline Project (No.B302)
文摘The free vibration analysis of cylindrical helical springs is carried out by means of an analytical study. In the governing equations of the motion of the springs, all displacement functions are defined at the centroid axis and also the effects of the rotational inertia, axial and shear deformations are included in the proposed model. Explicit analytical expressions which give the vibrating mode shapes are derived by rigorous application of the symbolic computing package MATHEMATICA and a process of searching is used to determine the exact natural frequencies. Numerical examples are provided for fixed-fixed boundary conditions. The free vibrational pa- rameters are chosen as the number of coils (n = 4- 14), the helix pitch angle (a = 5 - 30°) and as the ratio of the diameters of the cylinder and the wire (D/d = 4 - 18) in a wide range. Validation of the proposed model has been achieved through comparison with a finite element model using two-node standard beam elements and the results available in published literature, which in these cases indicates a very good correlation.
基金supported by the Natural Science Foundation of China(41572223,41172227)the Natural Science Foundation of Beijing(8152026)+1 种基金the Fundamental Research Funds for the Central Universities of China(2652015244,2652015245,2652015426)the National Key Project of Foundational Research and Development of China(973 Project)(2011CB403005)
文摘Based on their genesis, springs are commonly classified as depression spring, contact spring, overflow spring and fault spring, etc. In addition, a kind of springs, i.e., up-flow spring, can be found in the field. An aquifer is overlain by poorly-permeable unconsolidated sediments or relatively impervious formations. If the hydraulic head of the aquifer is higher than the land surface, groundwater may flow up to the ground surface through the local portion of the overlying aquicludes where the permeability is relatively good, and emerges as an up-flow spring. The common characteristics of an up-flow spring are discussed and summarized in this paper, and some examples of the up-flow springs are also given. Up-flow springs can flow up through local permeable zones in the overlying aquicludes rather than permeable faults. Although they cannot be found as frequently as depression springs, contact springs, overflow springs and fault springs etc., yet up-flow springs may occur in the form of normal-temperature springs, hot springs and salt springs.
基金co-supported by the National Key Project on Basic Research(2011CB403006)the Special Fund for Scientific Research of Central-leveled Academy(K2007-3-2)National Geological Survey(1212010818057,1212011120046)
文摘Microbial mats, mainly dominated by filamentous algae Calothrix and Oscillatoria, are well developed in Tibetan hot springs. A great number of fossil microorganisms, which existed as algae lamination in thermal depositional cesium-bearing geyserite in this area, are identified as Calothrix and Oscillatoria through microexamination and culture experiments. These microbial mats show the ability to accumulate cesium from spring water to the extent of cesium concentration of 0.46-1.03% cell dry weight, 900 times higher than that in water, and capture large numbers of cesium-bearing opal grain. Silicon dioxide colloid in spring water replaces and fills with the organism and deposits on it to form algae laminated geyserite after dehydration and congelation. Cesium in the microbial mats and opal grain is then reserved in the geyserite. Eventually, cesium-bearing algae laminated geyserite is formed. Study on cesium distribution in geyserite also shows that cesium content in algae lamination, especially in heavily compacted algae lamination, is higher than in the opal layer. For geyserite with no algae lamination or other organism structure, which is generally formed in spring water with low silicon content, cesium accumulation and cesium-bearing opal grain assembled by the microbial mats are also indispensable. After the microbial mats accumulating cesium from spring water, silicon dioxide colloid poorly replaces and fills with the organism to form opal grain-bearing tremellose microbial mats. The shape and structure of the organisms are then destroyed, resulting in cesium-bearing geyserite with no algae lamination structure after dehydration and congelation. It is then concluded that microbial mats in the spring area contribute to the enrichment of cesium in the formation of cesium-bearing geyserite, and a biological genesis of the geyserite, besides of the physical and chemical genesis, is likely.
基金This project is supported by National Natural Science Foundation of China(No.50075009) and SRF for ROCS, SEM.
文摘A new method is presented to describe and analyze the spatial compliance ofcoiled springs using screw theory. After an abbreviated description for the deformation of a beamelement using screw theory, the spatial compliance density for a beam element is derived based onthe fundamental material theory and reasonable assumptions, and the spatial compliance of the beamwith finite length is obtained by integral. The spatial compliance of coiled springs is furtheranalyzed using the spatial compliance density of the beam element. By calculating theeigencompliance and Ball's principle screws for the whole compliance of system, the complianceproperties varying with the basic physical parameters of the system are illustrated in detail. Thebasic ideas can be used for the design and application of the coiled springs and the other compliantmechanisms with spatial compliant beam element.
基金supported by the National Natural Science Foundation of China(Grant No.40972211)the US National Science Foundation(Grant Nos.ETBC-1024614 and OISE- 0968421 )
文摘Isoprenoidal glycerol dialkyl glycerol tetraethers (iGDGTs) from the Gulu hot springs (23--83.6 ℃, pH 〉 7) and Yangbajing hot springs (80-128 ℃, pH 〉 7) were analyzed in order to investigate the distribution of archaeal lipids among different hot springs in Tibet. A soil sample from Gulu was incubated at different temperatures and analyzed for changes in iGDGTs to help evaluate whether surrounding soil may contribute to the iGDGTs in hot springs. The sources of bacterial GDGTs (bGDGTs) in these hot springs were also investigated. The results revealed different profiles ofiGDGTs between Gulu and Yangbajing hot springs. Core iGDGTs and polar iGDGTs also presented different patterns in each hot spring. The PCA analysis showed that the structure of polar iGDGTs can be explained by three factors and suggested multiple sources of these compounds. Bivariate correlation analysis showed significant positive correlations between polar and core bGDGTs, suggesting the in situ production of bGDGTs in the hot springs. Furthermore, in the soil incubation experiment, temperature had the most significant influence on concentration of bGDGTs rather than iGDGTs, and polar bGDGTs had greater variability than core bGDGTs with changing temperature. Our results indicated that soil input had little influence on the composition of GDGTs in Tibetan hot springs.