The Upper Sinian bedded cherts are widely distributed on the southeast continental margin of the Yangtze plate, with a total thickness ranging from 20 to 150 m. The cherts are very simple in chemical composition, with...The Upper Sinian bedded cherts are widely distributed on the southeast continental margin of the Yangtze plate, with a total thickness ranging from 20 to 150 m. The cherts are very simple in chemical composition, with the contents of siliceous minerals exceeding 90% and those of other mineral species being very low. The total content of trace elements is considerably variable. The contents of most trace elements are low as compared with their crust clarke values. But these cherts are very rich in the trace elements Ba, As, Ab, Ag and U, coupled with relatively high contents of Fe, Mn and low contents of Al, Ti, and Mg. It can be identified as the cherts of hydrothermal origin in terms of the values of Fe/Ti, (Fe+Mn)/Ti, Al/(Al+Fe+Mn) and U/Th. In the Al\|Fe\|Mn, and Fe\|Mn\|(Cu+Ni+Co)×10 diagrams and lg \\|lg\, Cr\|Zr diagrams, all the samples from the area studied fall within the hydrothermal sediment field. All these characteristics show that the cherts are mainly the product of hydrothermal processes. The fact that the \{δ\{\}\+\{30\}Si\} values of the chert range from 0.0‰ to \{0.7‰\} with \{δ\{\}\+\{18\}O\} from 20.1‰ to 23.6‰ clearly manifests that the submarine hydrothermal water is the main source of silica.\;\;展开更多
Based on the wave radiation and diffraction theory, this paper investigates a new type breakwater with upper arcshaped plate by using the boundary element method(BEM). By comparing with other three designs of plate ty...Based on the wave radiation and diffraction theory, this paper investigates a new type breakwater with upper arcshaped plate by using the boundary element method(BEM). By comparing with other three designs of plate type breakwater(lower arc-shaped plate, single horizontal plate and double horizontal plate), this new type breakwater has been proved more effective. The wave exiting force, transmission and reflection coefficients are analyzed and discussed. In order to reveal the wave elimination mechanism of this type of breakwater, the velocity field around the breakwater is obtained. It is shown that:(1) The sway exciting force is minimal.(2) When the ratio of the submergence and wave amplitude is 0.05, the wave elimination effect will increase by 50% compared with other three types of breakwater.(3) The obvious backflow is found above the plate in the velocity field analysis.展开更多
In this paper, the method of relaxed boundary conditions is applied to rectangular plates with edges which are a sort of the mixture of simply supported portions and clamped portions, so that the lower limit of fundam...In this paper, the method of relaxed boundary conditions is applied to rectangular plates with edges which are a sort of the mixture of simply supported portions and clamped portions, so that the lower limit of fundamental frequency of such plates is evaluated. A kind of polynomial satisfying the displacement boundary conditions is designed, os that it is enabled to evaluate the upper limit of fundamental frequency by Ritz' method. The practical calculation examples solved by these methods have given satisfactory results. At the end of this paper, it is pointed out that the socalled exact solution of such plates usually evaluated by the force superposition method is essentially a kind of lower limit of solution, if the truncated error of series which occurs in actual calculation is considered.展开更多
为满足5.8 GHz雷达系统的需要,在HLMC55LP工艺中设计了一款12 bit SAR ADC,ADC的采样率为500 kHz/250 kHz两档可调,采用单调电容开关时序,且在电容阵列的高位部分加上2个冗余位设计,该冗余位对高位的CDAC建立误差,比较器误差都有一定的...为满足5.8 GHz雷达系统的需要,在HLMC55LP工艺中设计了一款12 bit SAR ADC,ADC的采样率为500 kHz/250 kHz两档可调,采用单调电容开关时序,且在电容阵列的高位部分加上2个冗余位设计,该冗余位对高位的CDAC建立误差,比较器误差都有一定的容忍能力,可以带来ADC性能上的提升。系统采用上极板采样,可以在采样周期结束的瞬间就开始逐位比较过程,省去了采用底极板采样第一拍CDAC建立的过程,提高了转换速度,相对于底极板采样也节省了一定的开关功耗。后仿结果表明,模拟输入20 kHz差分中频信号,在500 kHz采样频率,3.3 V电源电压下,ADC的有效位数为11.56 bit,SNR为71.04 dB,SFDR为80.37 dBc,功耗约为2 mW。展开更多
The free vibration problem of rectangular thin plates is rewritten as a new upper triangular matrixdifferential system.For the associated operator matrix,we find that the two diagonal block operators are Hamiltonian.M...The free vibration problem of rectangular thin plates is rewritten as a new upper triangular matrixdifferential system.For the associated operator matrix,we find that the two diagonal block operators are Hamiltonian.Moreover,the existence and completeness of normed symplectic orthogonal eigenfunction systems of these two blockoperators are demonstrated.Based on the completeness,the general solution of the free vibration of rectangular thinplates is given by double symplectic eigenfunction expansion method.展开更多
Objective:To evaluate the orthopedic effects of a new method to treat skeletal crossbite in the early mixed dentition.Methods:Twenty cases(5.8-7.5 years old)with skeletal crossbite were treated by bonding the bite pla...Objective:To evaluate the orthopedic effects of a new method to treat skeletal crossbite in the early mixed dentition.Methods:Twenty cases(5.8-7.5 years old)with skeletal crossbite were treated by bonding the bite plate combined with the face mask protracting the upper jaw.Cephalometric radio- graphs were taken and analyzed before and after treatments.Results:On average,in all 20 cases the max- illa was moved by 2.06 mm forward;the mandible was turned 2.45°downward and backward;the skeletal crossbites were corrected and the facial profiles were improved satisfactorily.The period of treatment was conducted for 1.7 months on average.Conclusion:A good effect can be achieved by bonding bite plate combined with the face mask protracting the upper jaw to treat skeletal crossbite in the early mixed denti- tion,which will benefit the craniofacial growth and the development of young children.展开更多
文摘The Upper Sinian bedded cherts are widely distributed on the southeast continental margin of the Yangtze plate, with a total thickness ranging from 20 to 150 m. The cherts are very simple in chemical composition, with the contents of siliceous minerals exceeding 90% and those of other mineral species being very low. The total content of trace elements is considerably variable. The contents of most trace elements are low as compared with their crust clarke values. But these cherts are very rich in the trace elements Ba, As, Ab, Ag and U, coupled with relatively high contents of Fe, Mn and low contents of Al, Ti, and Mg. It can be identified as the cherts of hydrothermal origin in terms of the values of Fe/Ti, (Fe+Mn)/Ti, Al/(Al+Fe+Mn) and U/Th. In the Al\|Fe\|Mn, and Fe\|Mn\|(Cu+Ni+Co)×10 diagrams and lg \\|lg\, Cr\|Zr diagrams, all the samples from the area studied fall within the hydrothermal sediment field. All these characteristics show that the cherts are mainly the product of hydrothermal processes. The fact that the \{δ\{\}\+\{30\}Si\} values of the chert range from 0.0‰ to \{0.7‰\} with \{δ\{\}\+\{18\}O\} from 20.1‰ to 23.6‰ clearly manifests that the submarine hydrothermal water is the main source of silica.\;\;
基金financially supported by the National Key Basic Research Program of China(Grant No.2013CB036101)the National Natural Science Foundation of China(Grant No.11702054)
文摘Based on the wave radiation and diffraction theory, this paper investigates a new type breakwater with upper arcshaped plate by using the boundary element method(BEM). By comparing with other three designs of plate type breakwater(lower arc-shaped plate, single horizontal plate and double horizontal plate), this new type breakwater has been proved more effective. The wave exiting force, transmission and reflection coefficients are analyzed and discussed. In order to reveal the wave elimination mechanism of this type of breakwater, the velocity field around the breakwater is obtained. It is shown that:(1) The sway exciting force is minimal.(2) When the ratio of the submergence and wave amplitude is 0.05, the wave elimination effect will increase by 50% compared with other three types of breakwater.(3) The obvious backflow is found above the plate in the velocity field analysis.
文摘In this paper, the method of relaxed boundary conditions is applied to rectangular plates with edges which are a sort of the mixture of simply supported portions and clamped portions, so that the lower limit of fundamental frequency of such plates is evaluated. A kind of polynomial satisfying the displacement boundary conditions is designed, os that it is enabled to evaluate the upper limit of fundamental frequency by Ritz' method. The practical calculation examples solved by these methods have given satisfactory results. At the end of this paper, it is pointed out that the socalled exact solution of such plates usually evaluated by the force superposition method is essentially a kind of lower limit of solution, if the truncated error of series which occurs in actual calculation is considered.
基金Supported by the National Natural Science Foundation of China under Grant No.10962004the Natural Science Foundation of Inner Mongolia under Grant No.2009BS0101+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education of China under Grant No.20070126002the Cultivation of Innovative Talent of "211 Project"of Inner Mongolia University
文摘The free vibration problem of rectangular thin plates is rewritten as a new upper triangular matrixdifferential system.For the associated operator matrix,we find that the two diagonal block operators are Hamiltonian.Moreover,the existence and completeness of normed symplectic orthogonal eigenfunction systems of these two blockoperators are demonstrated.Based on the completeness,the general solution of the free vibration of rectangular thinplates is given by double symplectic eigenfunction expansion method.
文摘Objective:To evaluate the orthopedic effects of a new method to treat skeletal crossbite in the early mixed dentition.Methods:Twenty cases(5.8-7.5 years old)with skeletal crossbite were treated by bonding the bite plate combined with the face mask protracting the upper jaw.Cephalometric radio- graphs were taken and analyzed before and after treatments.Results:On average,in all 20 cases the max- illa was moved by 2.06 mm forward;the mandible was turned 2.45°downward and backward;the skeletal crossbites were corrected and the facial profiles were improved satisfactorily.The period of treatment was conducted for 1.7 months on average.Conclusion:A good effect can be achieved by bonding bite plate combined with the face mask protracting the upper jaw to treat skeletal crossbite in the early mixed denti- tion,which will benefit the craniofacial growth and the development of young children.
