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促进学生体验和理解化工流程——从草木灰中提取粗碳酸钾的微型实验

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化学教育(中英文) 2025年第3期46卷 81-85页

作者：伍强黄荣霞湖北省天门中学天门市实验高级中学

对从草木灰中提取粗碳酸钾的实验进行了改进，设计了可代替酒精灯使用的微型炭炉，设计了微型电动搅拌器，设计了浸取压滤一体装置，极大缩短了实验时间，使得该实验更易推广。有目的地挖掘了各种商业成品的新用途，并应用在化学实验中... 详细信息

对从草木灰中提取粗碳酸钾的实验进行了改进，设计了可代替酒精灯使用的微型炭炉，设计了微型电动搅拌器，设计了浸取压滤一体装置，极大缩短了实验时间，使得该实验更易推广。有目的地挖掘了各种商业成品的新用途，并应用在化学实验中，使实验设备具有成本低、易搬运、节能、绿色化、普适性强等特点。

关键词：草木灰提取碳酸钾实验设计

A Neighborhood Union Condition for Fractional ID-[a, b]-factor-critical Graphs

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Acta Mathematicae Applicatae Sinica 2018年第4期34卷 775-781页

作者： Yuan YUAN rong-xia HAO Department of Mathematics Beijing Jiaotong University

Let a, b, r be nonnegative integers with 1 ≤ a ≤ b and r ≥ 2. Let G be a graph of order n with n 〉（a＋2 b）（r（a＋b）-2）/*** this paper, we prove that G is fractional ID-[a, b]-factor-critical if δ（G）≥bn/a＋2 b＋a（r-1）and ｜NG（x1） ∪ NG（x2） ∪…∪ NG（xr）｜ ≥（a＋b）n/（a＋2 b） for any independent subset {x1,x2,…,xr} in G. It is a generalization of Zhou et al.＇s previous result [Discussiones Mathematicae Graph Theory, 36： 409-418（2016）]in which r = 2 is discussed. Furthermore, we show that this result is best possible in some sense.

关键词： graph minimum degree neighborhood fractional [a b]-factor fractional ID-[a b]-factor-critical

A Note on Directed Genera of Some Tournaments

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Acta Mathematicae Applicatae Sinica 2018年第3期34卷 478-484页

作者： Jian-bing LIU rong-xia HAO Department of Mathematics Beijing Jiaotong University

An embedding of a digraph in an orientable surface is an embedding as the underlying graph and arcs in each region force a directed cycle. The directed genus is the minimum genus of surfaces in which the digraph can be directed embedded. Bonnington, Conder, Morton and McKenna [J. Cornbin. Theory Ser. B,85（2002） 1-20] gave the problem that which tournaments on n vertices have the directed genus [（n-3）（n-4）/12]the genus of Kn. In this paper, we use the current graph method to show that there exists a tournament, whichhas the directed genus[（n-3）（n-4）/12], on n vertices if and only if n = 3 or 7 （mod 12）.

关键词： digraph directed embedding directed genus surfaces

On the Inertia Index of a Mixed Graph in Terms of the Matching Number

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Acta Mathematicae Applicatae Sinica 2023年第3期39卷 591-604页

作者： Sheng-jie HE rong-xia HAO Ai-mei YU School of Mathematics and Statistics Beijing Jiaotong UniversityBeijing 100044China

A mixed graph G^(-) is obtained by orienting some edges of G, where G is the underlying graph of G^(-) . The positive inertia index, denoted by p~+( G), and the negative inertia index, denoted by n~-(G^(-) ), of a mixed graph G^(-) are the integers specifying the numbers of positive and negative eigenvalues of the Hermitian adjacent matrix of G^(-) , respectively. In this paper, the positive and negative inertia indices of the mixed unicyclic graphs are studied. Moreover, the upper and lower bounds of the positive and negative inertia indices of the mixed graphs are investigated, and the mixed graphs which attain the upper and lower bounds are characterized respectively.

关键词： Inertia index Mixed graph Matching number

Tomato Growth and Organic Acid Changes in Response to Partial Replacement of NO_3^--N by NH_4^+-N

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Pedosphere 2004年第2期14卷 159-164页

作者： DONGCai-xia SHENQi-rong WANGGe CollegeofResourcesandEnvironmentalSciences NanjingAgriculturalUniversityNanjing210095（China）／E-mail：cxdong@***

A hydroponic experiment was conducted to study the effect of partial replacement of NO-3-N by NH4+-N on the seedling growth and organic acid content of tomato (Lycopersicon esculentum Mill.). A completely randomized design was established with three replications and five treatments, i.e., NO-3-N/NH4+-N of 100/0, 75/25, 50/50, 25/75 and 0/100. Results showed that 25% replacement of NO3--N by NH4+-N significantly (P = 0.05) improved fresh and dry weight, revealing that a proper percentage of NH4+-N was important for tomato nitrogen nutrition. This could increase the plant growth even though tomato was a crop that preferred nitrate nutrition. Also an increase in the proportion of NH4+-N in the nutrient solution led to a significant decrease (P = 0.05) in malate, citrate and fumarate. However, the 25% NH4+-N plus 75% NO3--N treatment had no significant effect (P = 0.05) on the 2-ketoglutarate, succinate or oxalic acid content, showing that only some organic acids in tomato plants were affected. Only pyruvate increased significantly (P = 0.05), and it only increased for 25% and 50% replacement of NO3--N by NH4+-N. Metabolism of these organic acids, especially malate, citrate and fumarate, should be further studied at the molecular level in vegetables applied with different nitrogen forms.

关键词： NH_4^+-N nitrogen forms NO_3^--N organic acid tomato (Lycopersiconesculentum Mill.)

Interdecadal variability of the large-scale extreme hot event frequency over the middle and lower reaches of the Yangtze River basin and its related atmospheric patterns

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Atmospheric and Oceanic Science Letters 2018年第1期11卷 63-70页

作者： LI rong-xia SUN Jian-Qi Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijingChina Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science and TechnologyNanjingChina College of Earth Science University of Chinese Academy of SciencesBeijingChina

Based on daily maximum temperature data from Chinese weather stations for the period 1960- 2013, the characteristics of the interdecadal variability of large-scale extreme hot event （EHE） frequency over the middle and lower reaches of the Yangtze River basin （MLYR） are analyzed. It is found that the frequency of large-scale EHE over the MLYR experiences two significant interdecadal changes, around the early 1970s and early 2000s, having a more-less-more variability shape during the past half century. Furthermore, the EHE frequency interdecadal variability-related atmospheric circulation patterns are diagnosed. The results indicate the western Pacific subtropical high could not be the dominant atmospheric circulation associated with the interdecadal variability of the large-scale EHE frequency over the MLYR. In contrast, the dominant teleconnection pattern over the Eurasian continent, which is represented by the second empirical orthogonal function mode of the 200 hPa geopotential height, is closely related to the interdecadal variability of the EHE frequency over the MLYR. The results of this study deepen our understanding of the variability of the EHE frequency over the MLYR and its possible mechanism.

关键词： Extreme hot event decadalvariability teleconnection EOF

Evaluation of packet loss impairment on streaming video

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第z1期7卷 131-136页

作者： RUI Hua-xia LI Chong-rong QIU Sheng-ke Network Research Center Tsinghua University Beijing 100084 China Network Research Center Tsinghua University Beijing 100084 China Network Research Center Tsinghua University Beijing 100084 China

Video compression technologies are essential in video streaming application because they could save a great amount of network resources. However compressed videos are also extremely sensitive to packet loss which is inevitable in today's best effort IP network. Therefore we think accurate evaluation of packet loss impairment on compressed video is very important. In this work, we develop an analytic model to describe these impairments without the reference of the original video (NR) and propose an impairment metric based on the model, which takes into account both impairment length and impairment strength. To evaluate an impaired frame or video, we design a detection and evaluation algorithm (DE algorithm) to compute the above metric value. The DE algorithm has low computational complexity and is currently being implemented in the real-time monitoring module of our HDTV over IP system. The impairment metric and DE algorithm could also be used in adaptive system or be used to compare diffeient error concealment strategies.

关键词： Packet loss, Video streaming, MPEG-2 video, Video quality, No-Reference

Neighbor Connectivity of Two Kinds of Cayley Graphs

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Acta Mathematicae Applicatae Sinica 2018年第2期34卷 386-397页

作者： Yi-jie SHANG rong-xia HAO Mei-mei GU Mathematics Beijing Jiaotong University

In this paper, we determine the neighbor connectivity κNB of two kinds of Cayley graphs： alter- nating group networks ANn and star graphs Sn; and give the exact values of edge neighbor connectivity λNB of ANn and Cayley graphs generated by transposition trees Fn. Those are κNB（ANn） = n-1, λNB（ANn） = n-2 and κNB（Sn） = λNB（Гn） = n - 1.

关键词： neighbor connectivity edge neighbor connectivity Cayley graphs

Acoustic dipole radiation model for magnetoacoustic tomography with magnetic induction

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Chinese Physics B 2011年第8期20卷 263-270页

作者： Li Yi-Ling Ma Qing-Yu Zhang Dong xia rong-Min Department of Educational Technology Nanjing Normal University Nanjing 210097 China Key Laboratory of Optoelectronics of Jiangsu Province School of Physics and Technology Nanjing Normal University Nanjing 210046 China Institute of Acoustics Nanjing University Nanjing 210093 China University of Arkansas for Medical Science Little Rock AR 72205 USA

An acoustic dipole radiation model for magnetoacoustic tomography with magnetic induction （MAT-MI） is pro- posed, based on the analyses of one-dimensional tissue vibration, three-dimensional acoustic dipole radiation and acoustic waveform detection with a planar piston transducer. The collected waveforms provide information about the conductiv- ity boundaries in various vibration intensities and phases due to the acoustic dipole radiation pattern. Combined with the simplified back projection algorithm, the conductivity configuration of the measured layer in terms of shape and size can be reconstructed with obvious border stripes. The numerical simulation is performed for a two-layer cylindrical phantom model and it is also verified by the experimental results of MAT-MI for a tissue-like sample phantom. The proposed model suggests a potential application of conductivity differentiation and provides a universal basis for the further study of conductivity reconstruction for MAT-MI.

关键词： magnetoacoustic tomography with magnetic induction acoustic dipole radiation beampattern biological tissues