A frequency ratio RatioXH associated with two carrier frequencies in ppm is introduced for achieving auto-offsetting and -referencing (AOR) in biomolecular NMR. Once the center of 1H is referenced, all the offsets in ...A frequency ratio RatioXH associated with two carrier frequencies in ppm is introduced for achieving auto-offsetting and -referencing (AOR) in biomolecular NMR. Once the center of 1H is referenced, all the offsets in other dimensions are automatically determined and the centers of the spectral widths provide accurate indirect references. Since the scale in ppm is independent of the magnetic field strength, the AOR does not require manually updating carrier frequencies from time to time, making the multidimensional NMR experiments greatly simplified and reliable. It is extremely valuable when molecules need to be run a large number of experiments at different times and the data (chemical shifts, for example) need to be compared with each other. In AOR, the error arising from improper referencing of 1H is handed down in the same amount to the other nuclei being referenced. This error-inheritance provides a measure of accuracy in indirect referencing. The temperature dependence of the frequency ratio of DSS is derived with the first-order approximation and it can be used for temperature dependent AOR. For nuclei other than 13C, certain frequency ratios regarding TMS need to be derived (rather than measured) based on the recommended frequency ratios of DSS, thus avoiding conflicts and unifying the two standards.展开更多
Traditional technique such nanoindenter（NI） can＇t measure the local elastic modulus at nano-scale（lateral）. Atomic force acoustic microscopy （AFAM） is a dynamic method, which can quantitatively determine indent...Traditional technique such nanoindenter（NI） can＇t measure the local elastic modulus at nano-scale（lateral）. Atomic force acoustic microscopy （AFAM） is a dynamic method, which can quantitatively determine indentation modulus by measuring the contact resonance spectra for high order modes of the cantilever. But there are few reports on the effect of experimental factors, such length of cantilever, contact stiffness on measured value. For three different samples, including copper（Cu） film with 110 nm thickness, zinc（Zn） film of 90 nm thickness and glass slides, are prepared and tested, using referencing approach in which measurements are performed on the test and reference samples （it＇s elastic modulus is known）, and their contact resonance spectra are measured used the AFAM system experimentally. According to the vibration theory, from the lowest two contact resonance frequencies, the tip-sample contact stiffness is calculated, and then the values for the elastic properties of test sample, such as the indentation modulus, are determined. Using AFAM system, the measured indentation modulus of copper nano-film, zinc nano-film and glass slides are 113.53 GPa, 87.92 GPa and 57.04 GPa, which are agreement with literature values Mcu--105-130 GPa, Mzn = 88.44 GPa and Molass = 50-90 GPa. Furthermore, the sensitivity of contact resonance frequency to contact stiffness is analyzed theoretically. The results show that for the cantilevers with the length 160 pm, 225 μm and 520 μm respectively, when contact stiffness increases from 400 N/m to 600 N/m, the increments of first contact resonance frequency are 126 kHz, 93 kHz and 0.6 kHz, which show that the sensitivity of the contact resonance frequency to the contact stiffness reduces with the length of cantilever increasing. The novel method presented can characterize elastic modulus of near surface for nano-film and bulk material, and local elasticity of near surface can be evaluated by optimizing the experimental parameters using the AFAM system.展开更多
The phase referencing Very Long Baseline Interferometry(VLBI)technique is a newly developed tool to measure the angular position of a deep space exploration probe in the plane-of-the-sky.Through alternating observatio...The phase referencing Very Long Baseline Interferometry(VLBI)technique is a newly developed tool to measure the angular position of a deep space exploration probe in the plane-of-the-sky.Through alternating observations between the probe and a nearby reference radio source,their accurate relative angular separation can be obtained from the radio images generated by this technique.To meet the requirements of the current orbit determination software,differential delay should be firstly derived from those radio images.A method to resolve the differential phase delay from the phase referencing VLBI technique is proposed in this paper,and as well the mathematical model for differential phase ambiguity resolution is established.This method is verified with practical measurement data from the Chang’E-3 mission.The differential phase delay between the Chang’E-3 lander and rover was derived from the phase referencing VLBI measurements,and was then imported into the Shanghai astronomical observatory Orbit Determination Program(SODP)to calculate the position of the rover relative to the lander on the lunar surface.The results are consistent with those acquired directly from radio images,indicating that the differential phase ambiguity has been correctly resolved.The proposed method can be used to promote applications of the phase referencing VLBI technique in future lunar or deep space explorations,and more accurate orbit determination becomes promising.展开更多
For simplified processing, micro parts are handled as linked parts. The length of the frame structure of these linked parts can change during a multi-stage production process especially when forming is included. Hence...For simplified processing, micro parts are handled as linked parts. The length of the frame structure of these linked parts can change during a multi-stage production process especially when forming is included. Hence, the positions of individual parts are not constant within the linkage. An individual referencing of the parts becomes necessary in each production step. In this paper, a visual high-speed on-line part referencing system is presented and analyzed. Especially, the trade-off between the highest possible feed velocity and the demand of high accuracy in micro production is taken into account. In addition to this general characterization application related testing with stepwise positioning is performed.展开更多
Lowry's paper(1951,Journal of Biological Chemistry)is the most highly cited paper in the world up to 26th,December 2022.Laemmli's paper(1970,Nature)ranks second.These two papers are selected as our sample to c...Lowry's paper(1951,Journal of Biological Chemistry)is the most highly cited paper in the world up to 26th,December 2022.Laemmli's paper(1970,Nature)ranks second.These two papers are selected as our sample to compare respective dissemination networks of referencing errors.There are several types of referencing errors,and we focus on the so-called'double error",that is,the co-occurrence of a wrong volume number of a journal and a wrong beginning page number of a paper.Since the probability of a double error is extremely small,so that whenever double error occurs more than once,we can deduce definitely that there are some authors who copy references from the reference list of other publications.Based on the dissemination networks of the double errors of the above-mentioned two papers,three dissemination routes are confirmed.Route 1:copying references from another paper and citing that paper.Route 2:copying references from another paper without citing that paper.Route 3:Sharing at least one author with another paper which carries the same referencing error.Some suggestions are offered to reduce or eliminate the misconduct of copying references without any checking.展开更多
Soil classification is the foundation for exchange and extension of research findings in soil science and for modern management of soil resources. This study explained database and research methodology to create a cro...Soil classification is the foundation for exchange and extension of research findings in soil science and for modern management of soil resources. This study explained database and research methodology to create a cross-reference system for translating the Genetic Soil Classification of China (GSCC) into the Chinese Soil Taxonomy (CST). With the help of the CST keys, each of the 2 540 soil species in GSCC has been interpreted to its corresponding soil order, suborder, great group, and sub-group in CST. According to the methodology adopted, the assigned soil species have been linked one another to their corresponding polygons in the 1:1000000 digital soil map of China. Referencibility of each soil species between the GSCC and CST systems was determined statistically on the basis of distribution area of each soil species at a high taxon level of the two systems. The soils were then sorted according to their maximum referencibility and classified into three categories for discussion. There were 19 soil great groups in GSCC with maximum referencibility > 90% and 22 great groups between 60%-90%. These soil great groups could serve as cross-reference benchmarks. There were 19 great groups in GSCC with maximum referencibility < 60%, which could be used as cross-reference benchmarks until new and better results were available. For these soils, if the translation was made at a lower soil taxon level or on a regional basis, it would improve their referencibility enabling them to serve as new cross-reference benchmarks.展开更多
Terrain referenced navigation estimates an aircraft navigation status by utilizing a radar altimeter measuring a distance between the aircraft and terrain elevation. Accurate digital elevation map is essential to esti...Terrain referenced navigation estimates an aircraft navigation status by utilizing a radar altimeter measuring a distance between the aircraft and terrain elevation. Accurate digital elevation map is essential to estimate the aircraft states correctly. However, the elevation map cannot represent the real terrain perfectly and there exists map error between the estimated and the true maps. In this paper, an influence of the map error on measurement equation is analyzed and a technique to incorporate the error in the filter is proposed. The map error is divided into two sources, accuracy error and resolution error. The effectiveness of the suggested technique is verified by simulation results. The method modifies a sensor noise covariance only so there is no additional computational burden from the conventional filter.展开更多
The purpose of designing the assessment is to drive curriculum development and learning,and to promote students’inference making ability when reading at the college level.The focal construct of this study is inferenc...The purpose of designing the assessment is to drive curriculum development and learning,and to promote students’inference making ability when reading at the college level.The focal construct of this study is inference making based on text information and the reader’s background knowledge.Therefore,reading in the assignment means reading between the lines to learn the implied underlying meaning.This study applies a principled,theory-based approach to develop reading assessment.Test specification is made at the end.展开更多
文摘A frequency ratio RatioXH associated with two carrier frequencies in ppm is introduced for achieving auto-offsetting and -referencing (AOR) in biomolecular NMR. Once the center of 1H is referenced, all the offsets in other dimensions are automatically determined and the centers of the spectral widths provide accurate indirect references. Since the scale in ppm is independent of the magnetic field strength, the AOR does not require manually updating carrier frequencies from time to time, making the multidimensional NMR experiments greatly simplified and reliable. It is extremely valuable when molecules need to be run a large number of experiments at different times and the data (chemical shifts, for example) need to be compared with each other. In AOR, the error arising from improper referencing of 1H is handed down in the same amount to the other nuclei being referenced. This error-inheritance provides a measure of accuracy in indirect referencing. The temperature dependence of the frequency ratio of DSS is derived with the first-order approximation and it can be used for temperature dependent AOR. For nuclei other than 13C, certain frequency ratios regarding TMS need to be derived (rather than measured) based on the recommended frequency ratios of DSS, thus avoiding conflicts and unifying the two standards.
基金supported by National Natural Science Foundation of China(Grant No. 50775005)General Program of Science and Technology Development Project of Beijing Municipal Education Commission(Grant No. KM201110015009)
文摘Traditional technique such nanoindenter（NI） can＇t measure the local elastic modulus at nano-scale（lateral）. Atomic force acoustic microscopy （AFAM） is a dynamic method, which can quantitatively determine indentation modulus by measuring the contact resonance spectra for high order modes of the cantilever. But there are few reports on the effect of experimental factors, such length of cantilever, contact stiffness on measured value. For three different samples, including copper（Cu） film with 110 nm thickness, zinc（Zn） film of 90 nm thickness and glass slides, are prepared and tested, using referencing approach in which measurements are performed on the test and reference samples （it＇s elastic modulus is known）, and their contact resonance spectra are measured used the AFAM system experimentally. According to the vibration theory, from the lowest two contact resonance frequencies, the tip-sample contact stiffness is calculated, and then the values for the elastic properties of test sample, such as the indentation modulus, are determined. Using AFAM system, the measured indentation modulus of copper nano-film, zinc nano-film and glass slides are 113.53 GPa, 87.92 GPa and 57.04 GPa, which are agreement with literature values Mcu--105-130 GPa, Mzn = 88.44 GPa and Molass = 50-90 GPa. Furthermore, the sensitivity of contact resonance frequency to contact stiffness is analyzed theoretically. The results show that for the cantilevers with the length 160 pm, 225 μm and 520 μm respectively, when contact stiffness increases from 400 N/m to 600 N/m, the increments of first contact resonance frequency are 126 kHz, 93 kHz and 0.6 kHz, which show that the sensitivity of the contact resonance frequency to the contact stiffness reduces with the length of cantilever increasing. The novel method presented can characterize elastic modulus of near surface for nano-film and bulk material, and local elasticity of near surface can be evaluated by optimizing the experimental parameters using the AFAM system.
基金the National Natural Science Foundation of China(Grant Nos.42030110,61603008 and U1831132)the Innovation Group of Natural Fund of Hubei Province(2018CFA087)。
文摘The phase referencing Very Long Baseline Interferometry(VLBI)technique is a newly developed tool to measure the angular position of a deep space exploration probe in the plane-of-the-sky.Through alternating observations between the probe and a nearby reference radio source,their accurate relative angular separation can be obtained from the radio images generated by this technique.To meet the requirements of the current orbit determination software,differential delay should be firstly derived from those radio images.A method to resolve the differential phase delay from the phase referencing VLBI technique is proposed in this paper,and as well the mathematical model for differential phase ambiguity resolution is established.This method is verified with practical measurement data from the Chang’E-3 mission.The differential phase delay between the Chang’E-3 lander and rover was derived from the phase referencing VLBI measurements,and was then imported into the Shanghai astronomical observatory Orbit Determination Program(SODP)to calculate the position of the rover relative to the lander on the lunar surface.The results are consistent with those acquired directly from radio images,indicating that the differential phase ambiguity has been correctly resolved.The proposed method can be used to promote applications of the phase referencing VLBI technique in future lunar or deep space explorations,and more accurate orbit determination becomes promising.
文摘For simplified processing, micro parts are handled as linked parts. The length of the frame structure of these linked parts can change during a multi-stage production process especially when forming is included. Hence, the positions of individual parts are not constant within the linkage. An individual referencing of the parts becomes necessary in each production step. In this paper, a visual high-speed on-line part referencing system is presented and analyzed. Especially, the trade-off between the highest possible feed velocity and the demand of high accuracy in micro production is taken into account. In addition to this general characterization application related testing with stepwise positioning is performed.
基金the National Natural Science Foundation of China(Grant Number 71603073).
文摘Lowry's paper(1951,Journal of Biological Chemistry)is the most highly cited paper in the world up to 26th,December 2022.Laemmli's paper(1970,Nature)ranks second.These two papers are selected as our sample to compare respective dissemination networks of referencing errors.There are several types of referencing errors,and we focus on the so-called'double error",that is,the co-occurrence of a wrong volume number of a journal and a wrong beginning page number of a paper.Since the probability of a double error is extremely small,so that whenever double error occurs more than once,we can deduce definitely that there are some authors who copy references from the reference list of other publications.Based on the dissemination networks of the double errors of the above-mentioned two papers,three dissemination routes are confirmed.Route 1:copying references from another paper and citing that paper.Route 2:copying references from another paper without citing that paper.Route 3:Sharing at least one author with another paper which carries the same referencing error.Some suggestions are offered to reduce or eliminate the misconduct of copying references without any checking.
基金Project supported by the National Natural Science Foundation of China (No. 40471081)the Frontal Field Project of the Chinese Academy of Sciences (No. ISSASIP0201) the Key Innovation Project of Chinese Academy of Sciences (No.KZCX3-SW-427).
文摘Soil classification is the foundation for exchange and extension of research findings in soil science and for modern management of soil resources. This study explained database and research methodology to create a cross-reference system for translating the Genetic Soil Classification of China (GSCC) into the Chinese Soil Taxonomy (CST). With the help of the CST keys, each of the 2 540 soil species in GSCC has been interpreted to its corresponding soil order, suborder, great group, and sub-group in CST. According to the methodology adopted, the assigned soil species have been linked one another to their corresponding polygons in the 1:1000000 digital soil map of China. Referencibility of each soil species between the GSCC and CST systems was determined statistically on the basis of distribution area of each soil species at a high taxon level of the two systems. The soils were then sorted according to their maximum referencibility and classified into three categories for discussion. There were 19 soil great groups in GSCC with maximum referencibility > 90% and 22 great groups between 60%-90%. These soil great groups could serve as cross-reference benchmarks. There were 19 great groups in GSCC with maximum referencibility < 60%, which could be used as cross-reference benchmarks until new and better results were available. For these soils, if the translation was made at a lower soil taxon level or on a regional basis, it would improve their referencibility enabling them to serve as new cross-reference benchmarks.
文摘Terrain referenced navigation estimates an aircraft navigation status by utilizing a radar altimeter measuring a distance between the aircraft and terrain elevation. Accurate digital elevation map is essential to estimate the aircraft states correctly. However, the elevation map cannot represent the real terrain perfectly and there exists map error between the estimated and the true maps. In this paper, an influence of the map error on measurement equation is analyzed and a technique to incorporate the error in the filter is proposed. The map error is divided into two sources, accuracy error and resolution error. The effectiveness of the suggested technique is verified by simulation results. The method modifies a sensor noise covariance only so there is no additional computational burden from the conventional filter.
文摘The purpose of designing the assessment is to drive curriculum development and learning,and to promote students’inference making ability when reading at the college level.The focal construct of this study is inference making based on text information and the reader’s background knowledge.Therefore,reading in the assignment means reading between the lines to learn the implied underlying meaning.This study applies a principled,theory-based approach to develop reading assessment.Test specification is made at the end.
