单磁芯可控饱和电抗器控制量研究

提出了在常规单磁芯可控饱和电抗器的结构中增加一个检测绕组。当磁芯中存在直流偏磁磁势时,分析检测绕组输出端电压与直流偏磁磁势之间的物理关系。研究得出,当磁芯中存在正偏磁时,检测绕组输出端电压的负峰值与直流偏磁磁势是线性关系;当磁芯中存在负偏磁时,检测绕组输出端电压的正峰值与直流偏磁磁势是线性关系;且检测线圈输出端电压的峰峰值、有效值和正负半波有效值之差与直流偏磁磁势有关但均不是线性关系。试制了样机,实验结果验证了理论分析的正确性。在常规单磁芯可控饱和电抗器的结构中增加检测绕组,是可以研究当有直流偏磁磁势作用时磁芯的工作特性的,并且证明了检测绕组输出端电压的一些特征电压量如峰峰值、有效值和正负半波有效值之差均可以作为反馈控制量。

Elemental characteristics of lacustrine oil shale and its controlling factors of palaeo-sedimentary environment on oil yield： a case from Chang 7 oil layer of Triassic Yanchang Formation in southern Ordos Basin

As an important unconventional resource, oil shale has received widespread attention. The oil shale of the Chang 7 oil layer from Triassic Yanchang Formation in Ordos Basin represents the typical lacustrine oil shale in China. Based on analyzing trace elements and oil yield from boreholes samples, characteristics and paleo-sedi- mentary environments of oil shale and relationship between paleo-sedimentary environment and oil yield were studied. With favorable quality, oil yield of oil shale varies from 1.4% to 9.1%. Geochemical data indicate that the paleo-redox condition of oil shale＇s reducing condition from analyses of V/Cr, V/（V ＋ Ni）, U/Th, δU, and authi genic uranium. Equivalent Boron, Sp, and Sr/Ba illustrate that paleosalinity of oil shale is dominated by fresh water. The paleoclimate of oil shale is warm and humid by calculating the chemical index of alteration and Sr/Cu. Fe/Ti and （Fe ＋ Mn）/Ti all explain that there were hot water activities during the sedimentary period of oil shale. In terms of Zr/Rb, paleohydrodynamics of oil shale is weak. By means of Co abundance and U/Th, paleo-water-depth of oil shale is from 17.30 to 157.26 m, reflecting sedimentary environment which is mainly in semi deep-deep lake facies. Correlation analyses between oil yield and six paleoenvironmental factors show that the oil yield of oil shale is mainly controlled by paleo-redox conditions, paleoclimate, hot water activities, and depth of water.Paleosalinity and paleohydrodynamics have an inconspicuous influence on oil yield.

Data organization and management of mine typical object spectral libraries

With the development of mining industry,people have obtained profits from it,but they are facing environmental damages.In order to monitor these environmental changes,a spectral library is set up for the spectrum data organization and management of mine typical objects.Most of the spectrum data come from the long-term field measuring in mining area and other spectral libraries.For the data quality control and error detection in the measuring data,an inner precision calculation method is presented and a series of interactive graphical controls are developed for the spectrum visualization and analysis.Through extracting and saving spectrum characters for the mine typical objects,realizs spectrum matching and classification for new measured spectrum samples are realized by using Euclidean distance,Aitchison distance,Pearson correlation coefficient and vector angular cosine methods.Based on the matching result,this work is able to gather dynamically physicochemical environment parameters from the library and gives an early warning for the mine environmental changes.

Control characteristics of D + A combined multi-pump controlled system

In order to solve the flow mismatch problem between pumping source output and workload demand,a novel configuration of D + A combined multi-pump controlled hydraulic system,similar to a pump-controlled system,is proposed for a large power hydraulic system in this study. This novel configuration consists of several parallel fixed displacement pumps of different sizes and proportional variable displacement pumps,which is controlled by digital signal( on/off) and analog signal respectively( D + A pumps). The system flow is divided into two parts,one is the total flow from fixed displacement pumps,and the other is the rest desired flow supplied by variable displacement pumps to smooth and improve the demand flow. First,basic design principles and evaluation indicators of the proposed system are introduced. Then,a flow state matrix of the binary-coding digital pumps( 1: 2: 4) is obtained to provide the control signals of pumps. Experimental results show that the system output flow tracks well with acceptable flow deviation,though a little lag behind input signal.

mRNA enrichment protocols determine the quantification characteristics of external RNA spike-in controls in RNA-Seq studies

RNA-Seq promises to be used in clinical settings as a gene-expression profiling tool;however,questions about its variability and biases remain and need to be addressed.Thus,RNA controls with known concentrations and sequence identities originally developed by the External RNA Control Consortium(ERCC) for microarray and qPCR platforms have recently been proposed for RNA-Seq platforms,but only with a limited number of samples.In this study,we report our analysis of RNA-Seq data from 92 ERCC controls spiked in a diverse collection of 447 RNA samples from eight ongoing studies involving five species(human,rat,mouse,chicken,and Schistosoma japonicum) and two mRNA enrichment protocols,i.e.,poly(A) and RiboZero.The entire collection of datasets consisted of 15650143175 short sequence reads,131603796(i.e.,0.84%) of which were mapped to the 92 ERCC references.The overall ERCC mapping ratio of 0.84% is close to the expected value of 1.0% when assuming a 2.0% mRNA fraction in total RNA,but showed a difference of 2.8-fold across studies and 4.3-fold among samples from the same study with one tissue type.This level of fluctuation may prevent the ERCC controls from being used for cross-sample normalization in RNA-Seq.Furthermore,we observed striking biases of quantification between poly(A) and RiboZero which are transcript-specific.For example,ERCC-00116 showed a 7.3-fold under-enrichment in poly(A) compared to RiboZero.Extra care is needed in integrative analysis of multiple datasets and technical artifacts of protocol differences should not be taken as true biological findings.

Comparative study on main compounds in Ginkgo biloba L. base on mathematical statistics

In this paper,an HPLC-DAD-ELSD method was developed to determine main 20 components of Ginkgo biloba L.leaves from different ages and sources,including six flavonol glycosides,five terpene lactones and nine organic acids.Using statistics method and establishing relevant mathematics models,the measured data has proceeded correlation analysis,principal component analysis,and regression statistics and the results showed generality and specific characteristics.We defined p-hydroxybenzoic acid,catechinic,KRcG and ginkgolide A as characteristic indexes representing commonness and speciality of Ginkgo biloba L.leaf.The four characteristic indexes can reflect the quality of Ginkgo biloba L.leaf,and the intermal relations between them are significant.The contents of other compounds could define the quantity relation with characteristic markers.It simplified the approach of quality control,and provided a basis for quality control of Ginkgo biloba L.

Matrix perturbation based approach for sensitivity analysis of eigen-solutions in a microgrid

Sensitivities of eigen-solutions to control variables play an important role in microgrid studies,such as coordinated optimal design of controllers and parameters,robust stability analysis on control variables,oscillation modes analysis on a system,etc.Considering the importance of sensitivities and the complexity of state matrix in a microgrid,parameter perturbations are utilized in this paper to analyze the construction characteristics of state matrix.Then,the sensitivities of eigenvalues and eigenvectors to control variables are obtained based on the first-order matrix perturbation theory,which makes the complex derivations of sensitivity formulas and repeated solutions of eigenvalue problem unnecessary.Finally,the effectiveness of the matrix perturbation based approach for sensitivity calculation in a microgrid is verified by a numerical example on a low-voltage microgrid prototype.