Quantitative changes in main parameters of secondary xylem during aging process were studied in four trees of Pinus bungeana collected from two different sites.No marked difference was found in the width of heartwo...Quantitative changes in main parameters of secondary xylem during aging process were studied in four trees of Pinus bungeana collected from two different sites.No marked difference was found in the width of heartwood, transition zone and sapwood at four cardinal directions and a wider sapwood and a narrower heartwood were noted in fast grown trees than in slowly grown ones. Earlywood generally showed a higher percentage of aspirated pits than latewood regardless of the age and growth conditions of the trees in addition , the earliest dead cells and the last living cells in the marginal cells were found a bit earlier than those in the central cells. It thus seems appropriate to conclude that the death of cells results largely from decrease of fluid permeability as the number of aspirated pits increases during aging process.展开更多
Using wavelet analysis,regression analysis and the Mann-Kendall test,this paper analyzed time-series(1959-2006) weather data from 23 meteorological stations in an attempt to characterize the climate change in the Tari...Using wavelet analysis,regression analysis and the Mann-Kendall test,this paper analyzed time-series(1959-2006) weather data from 23 meteorological stations in an attempt to characterize the climate change in the Tarim River Basin of Xinjiang Uygur Autonomous Region,China.Major findings are as follows:1) In the 48-year study period,average annual temperature,annual precipitation and average annual relative humidity all presented nonlinear trends.2) At the 16-year time scale,all three climate indices unanimously showed a rather flat before 1964 and a detectable pickup thereafter.At the 8-year time scale,an S-shaped nonlinear and uprising trend was revealed with slight fluctuations in the entire process for all three indices.Incidentally,they all showed similar pattern of a slight increase before 1980 and a noticeable up-swing afterwards.The 4-year time scale provided a highly fluctuating pattern of periodical oscillations and spiral increases.3) Average annual relative humidity presented a negative correlation with average annual temperature and a positive correlation with annual precipitation at each time scale,which revealed a close dynamic relationship among them at the confidence level of 0.001.4) The Mann-Kendall test at the 0.05 confidence level demonstrated that the climate warming trend,as represented by the rising average annual temperature,was remarkable,but the climate wetting trend,as indicated by the rising annual precipitation and average annual relative humidity,was not obvious.展开更多
Reduction roasting-acid leaching process was utilized to process high-iron-content manganese oxide ore using black charcoal as reductant. The results indicate that, compared with the traditional reductant of anthracit...Reduction roasting-acid leaching process was utilized to process high-iron-content manganese oxide ore using black charcoal as reductant. The results indicate that, compared with the traditional reductant of anthracite, higher manganese extraction efficiency is achieved at lower roasting temperature and shorter residence time. The effects of roasting parameters on the leaching efficiency of Mn and Fe were studied, and the optimal parameters are determined as follows: roasting temperature is 650 °C, residence time is 40 min, and black charcoal dosage is 10%(mass fraction). Under these conditions, the leaching efficiency of Mn reaches 82.37% while that of Fe is controlled below 7%. XRD results show that a majority of MnO2 and Fe2O3 in the raw ore are reduced to MnO and Fe3O4, respectively.展开更多
Results of investigations into the CO2 content in tree disc rings by the method proposed here have shown that a considerable part of CO2 generated under cell respiration is found in tree stems. Besides, annual CO2 dis...Results of investigations into the CO2 content in tree disc rings by the method proposed here have shown that a considerable part of CO2 generated under cell respiration is found in tree stems. Besides, annual CO2 distribution in tree rings exhibits a well-defined cyclicity. Results obtained from investigations into long-term CO2 and H2O variations in tree discs performed by different methods are presented. Wavelet and spectral analyses of the relationship between CO2 and H2O variations in a Siberian stone pine disc and meteorological parameters were made. The CO2 annual distributions of seven spruce tree discs were examined by the Caterpiller-SSA method. Wood samples of Siberian stone pine and spruce trees were taken from the same site in Tomsk region （Siberia, Russia） that characterized by an optimum growth habitat. Conclusions are made regarding the response of the annual CO2 and H2O conifer disc tree ring distributions to different climatic factors.展开更多
In the last decade, parametric and generative design techniques become quite popular for form-finding strategies or for pushing automation in design processes. Nevertheless, these techniques could be applied in engine...In the last decade, parametric and generative design techniques become quite popular for form-finding strategies or for pushing automation in design processes. Nevertheless, these techniques could be applied in engineering processes as well in order to improve the effectiveness and the efficiency of manufacturing processes in BI （building industry）. Focusing on the case study of GLT （glued-laminated timber）, this paper shows the procedure of programming a parametric algorithm adopted by authors that pursues two specific design intents： reducing the usage of unneeded high-quality raw material and improving the efficiency of production processes by producing DF （digital fabrication） contents for standard production systems of GLT. According to different European and international standards, thanks to FEM （finite element model） simulations and curvature analysis, the algorithm allows saving at least 33% of high-quality raw material and, according to early first surveys on a standard production system, 30% of operation time among product engineering-processes.展开更多
Studied the changes of heat physical parameters, gas concentration of O_2, CO,CH_4 and H_2, and temperature through full scale wood fire experiments in a tunnel and simulationby FLUNET, a kind of computational fluid d...Studied the changes of heat physical parameters, gas concentration of O_2, CO,CH_4 and H_2, and temperature through full scale wood fire experiments in a tunnel and simulationby FLUNET, a kind of computational fluid dynamics software.The results showthat the wood fire experiment and simulation are both oxygen-enriched combustions,which show that the simulation results coincide with the experiment.The results also provethat it is difficult for oxygen-enriched combustion to cause secondary disasters.Somesuggestions were put forward to prevent the occurrence of secondary disasters effectively.展开更多
The discussed topic of isolating certain parameters which describe the timbre in connection with bocals of bassoons is of major interest for manufacturers and artist likewise since a reduction in the overall shear str...The discussed topic of isolating certain parameters which describe the timbre in connection with bocals of bassoons is of major interest for manufacturers and artist likewise since a reduction in the overall shear stress of these kinds of technical diffusors is very helpful but not sufficient. The timbre seen from the side of the musician has to be the same. Up to now two criteria have been isolated which have a deep influence on the easier blowing of the bassoon and on the comparable timbre due to geometrical reasons. If the geometrical outer contour is designed carefully, it is possible to modify the shape and preserve the timbre.展开更多
文摘Quantitative changes in main parameters of secondary xylem during aging process were studied in four trees of Pinus bungeana collected from two different sites.No marked difference was found in the width of heartwood, transition zone and sapwood at four cardinal directions and a wider sapwood and a narrower heartwood were noted in fast grown trees than in slowly grown ones. Earlywood generally showed a higher percentage of aspirated pits than latewood regardless of the age and growth conditions of the trees in addition , the earliest dead cells and the last living cells in the marginal cells were found a bit earlier than those in the central cells. It thus seems appropriate to conclude that the death of cells results largely from decrease of fluid permeability as the number of aspirated pits increases during aging process.
基金Under the auspices of the Second-stage Knowledge Innovation Programs of Chinese Academy of Sciences (No KZCX2-XB2-03,KZCX2-YW-127)National Natural Science Foundation of China (No 40671014)Shanghai Academic Discipline Project (Human Geography) (No B410)
文摘Using wavelet analysis,regression analysis and the Mann-Kendall test,this paper analyzed time-series(1959-2006) weather data from 23 meteorological stations in an attempt to characterize the climate change in the Tarim River Basin of Xinjiang Uygur Autonomous Region,China.Major findings are as follows:1) In the 48-year study period,average annual temperature,annual precipitation and average annual relative humidity all presented nonlinear trends.2) At the 16-year time scale,all three climate indices unanimously showed a rather flat before 1964 and a detectable pickup thereafter.At the 8-year time scale,an S-shaped nonlinear and uprising trend was revealed with slight fluctuations in the entire process for all three indices.Incidentally,they all showed similar pattern of a slight increase before 1980 and a noticeable up-swing afterwards.The 4-year time scale provided a highly fluctuating pattern of periodical oscillations and spiral increases.3) Average annual relative humidity presented a negative correlation with average annual temperature and a positive correlation with annual precipitation at each time scale,which revealed a close dynamic relationship among them at the confidence level of 0.001.4) The Mann-Kendall test at the 0.05 confidence level demonstrated that the climate warming trend,as represented by the rising average annual temperature,was remarkable,but the climate wetting trend,as indicated by the rising annual precipitation and average annual relative humidity,was not obvious.
基金Project(2013JSJJ028)supported by the Teachers’Research Fund of Central South University,ChinaProject supported by Co-Innovation Center for Clean and Efficient Utilization of Strategic Mineral Resources,China
文摘Reduction roasting-acid leaching process was utilized to process high-iron-content manganese oxide ore using black charcoal as reductant. The results indicate that, compared with the traditional reductant of anthracite, higher manganese extraction efficiency is achieved at lower roasting temperature and shorter residence time. The effects of roasting parameters on the leaching efficiency of Mn and Fe were studied, and the optimal parameters are determined as follows: roasting temperature is 650 °C, residence time is 40 min, and black charcoal dosage is 10%(mass fraction). Under these conditions, the leaching efficiency of Mn reaches 82.37% while that of Fe is controlled below 7%. XRD results show that a majority of MnO2 and Fe2O3 in the raw ore are reduced to MnO and Fe3O4, respectively.
文摘Results of investigations into the CO2 content in tree disc rings by the method proposed here have shown that a considerable part of CO2 generated under cell respiration is found in tree stems. Besides, annual CO2 distribution in tree rings exhibits a well-defined cyclicity. Results obtained from investigations into long-term CO2 and H2O variations in tree discs performed by different methods are presented. Wavelet and spectral analyses of the relationship between CO2 and H2O variations in a Siberian stone pine disc and meteorological parameters were made. The CO2 annual distributions of seven spruce tree discs were examined by the Caterpiller-SSA method. Wood samples of Siberian stone pine and spruce trees were taken from the same site in Tomsk region （Siberia, Russia） that characterized by an optimum growth habitat. Conclusions are made regarding the response of the annual CO2 and H2O conifer disc tree ring distributions to different climatic factors.
文摘In the last decade, parametric and generative design techniques become quite popular for form-finding strategies or for pushing automation in design processes. Nevertheless, these techniques could be applied in engineering processes as well in order to improve the effectiveness and the efficiency of manufacturing processes in BI （building industry）. Focusing on the case study of GLT （glued-laminated timber）, this paper shows the procedure of programming a parametric algorithm adopted by authors that pursues two specific design intents： reducing the usage of unneeded high-quality raw material and improving the efficiency of production processes by producing DF （digital fabrication） contents for standard production systems of GLT. According to different European and international standards, thanks to FEM （finite element model） simulations and curvature analysis, the algorithm allows saving at least 33% of high-quality raw material and, according to early first surveys on a standard production system, 30% of operation time among product engineering-processes.
基金Supported by the National"Eleventh Five-Year"Key Scientific and Technological Support Program Project(2007BAK22B04)2008 Independent Task(SKLCRSM08B12)
文摘Studied the changes of heat physical parameters, gas concentration of O_2, CO,CH_4 and H_2, and temperature through full scale wood fire experiments in a tunnel and simulationby FLUNET, a kind of computational fluid dynamics software.The results showthat the wood fire experiment and simulation are both oxygen-enriched combustions,which show that the simulation results coincide with the experiment.The results also provethat it is difficult for oxygen-enriched combustion to cause secondary disasters.Somesuggestions were put forward to prevent the occurrence of secondary disasters effectively.
文摘The discussed topic of isolating certain parameters which describe the timbre in connection with bocals of bassoons is of major interest for manufacturers and artist likewise since a reduction in the overall shear stress of these kinds of technical diffusors is very helpful but not sufficient. The timbre seen from the side of the musician has to be the same. Up to now two criteria have been isolated which have a deep influence on the easier blowing of the bassoon and on the comparable timbre due to geometrical reasons. If the geometrical outer contour is designed carefully, it is possible to modify the shape and preserve the timbre.
