Development of a novel critical nitrogen concentration-cumulative transpiration curve for optimizing nitrogen management under varying irrigation conditions in winter wheat

Accurate nitrogen(N)nutrition diagnosis is essential for improving N use efficiency in crop production.The widely used critical N(Nc)dilution curve traditionally depends solely on agronomic variables,neglecting crop water status.With three-year field experiments with winter wheat,encompassing two irrigation levels(rainfed and irrigation at jointing and anthesis)and three N levels(0,180,and 270 kg ha1),this study aims to establish a novel approach for determining the Nc dilution curve based on crop cumulative transpiration(T),providing a comprehensive analysis of the interaction between N and water availability.The Nc curves derived from both crop dry matter(DM)and T demonstrated N concentration dilution under different conditions with different parameters.The equation Nc=6.43T0.24 established a consistent relationship across varying irrigation regimes.Independent test results indicated that the nitrogen nutrition index(NNI),calculated from this curve,effectively identifies and quantifies the two sources of N deficiency:insufficient N supply in the soil and insufficient soil water concentration leading to decreased N availability for root absorption.Additionally,the NNI calculated from the Nc-DM and Nc-T curves exhibited a strong negative correlation with accumulated N deficit(Nand)and a positive correlation with relative grain yield(RGY).The NNI derived from the Nc-T curve outperformed the NNI derived from the Nc-DM curve concerning its relationship with Nand and RGY,as indicated by larger R2 values and smaller AIC.The novel Nc curve based on T serves as an effective diagnostic tool for assessing winter wheat N status,predicting grain yield,and optimizing N fertilizer management across varying irrigation conditions.These findings would provide new insights and methods to improve the simulations of water-N interaction relationship in crop growth models.

基于CRITIC-加权灰色关联分析的年度洪涝灾情评估模型及应用

洪涝灾情评估能够直观呈现洪涝灾害强度和破坏程度,准确评估洪涝灾情是有针对性开展防洪减灾工作的基础。为充分表征洪涝灾害范围及深度,基于洪涝灾害的主要承灾体,从人口受灾、农作物受灾、房屋倒损、水利防洪设施损坏和经济损失5个洪涝灾害主要影响层面筛选洪涝灾情评估指标,分目标层、因子层、指标层构建全国及各地区年度洪涝灾情评估指标体系;基于年度洪涝灾害等级和年度洪涝灾害综合损失程度评估年度洪涝灾情,通过耦合CRITIC权重法和灰色关联分析模型构建CRITIC-加权灰色关联分析模型进行年度洪涝灾害等级评估,采用灾情指数法进行年度洪涝灾害综合损失程度评估;基于ArcGIS直观呈现空间数据的优势,将各地区年度洪涝灾害等级及综合损失程度采用区划图的形式展现。基于以上方法对2006-2021年全国及各地区进行年度洪涝灾情评估,结果表明:在全国年度洪涝灾情评估结果中,2010年为特大洪涝灾害,2013年和2016年为重大洪涝灾害;在各地区年度洪涝灾情评估结果中,湖南省2006年和2017年、河南省2021年年度洪涝灾害等级达到特大洪涝灾害;历年洪涝灾情较重且灾情频次较高的省份依次是四川省、湖南、湖北、江西、广东、海南;基于CRITIC-加权灰色关联分析模型和灾情指数法的年度洪涝灾情评估结果,可作为地区开展防洪减灾工作的依据。

基于CRITIC-TOPSIS模型的图书馆图书供应商评价研究

[目的/意义]旨在构建图书供应商的评价指标体系与评价模型,为图书馆优选图书供应商提供决策依据和方法。[方法/过程]以BSC模型为分析基础从供应商的影响力、供应能力、服务水平、价格、响应能力等维度形成了图书供应商的评价指标体系,构建了CRITIC-TOPSIS评价模型,以对图书供应商进行评价和选择。[结果/结论]该评价模型考虑了评价指标间的变异性和相关性,缓解了选择图书供应商时存在的主观不确定性,可以为图书馆选择优质图书供应商提供方法和指导。

Determination of critical nitrogen dilution curve based on leaf area index for winter wheat in the Guanzhong Plain, Northwest China

Excessive use of nitrogen (N) fertilizers in agricultural systems increases the cost of production and risk of environmental pollution. Therefore, determination of optimum N requirements for plant growth is necessary. Previous studies mostly established critical N dilution curves based on aboveground dry matter (DM) or leaf dry matter (LDM) and stem dry matter (SDM), to diagnose the N nutrition status of the whole plant. As these methods are time consuming, we investigated the more rapidly determined leaf area index (LAI) method to establish the critical nitrogen (Nc) dilution curve, and the curve was used to diagnose plant N status for winter wheat in Guanzhong Plain in Northwest China. Field experiments were conducted using four N fertilization levels (0, 105, 210 and 315 kg ha?1) applied to six wheat cultivars in the 2013–2014 and 2014–2015 growing seasons. LAI, DM, plant N concentration (PNC) and grain yield were determined. Data points from four cultivars were used for establishing the Nc curve and data points from the remaining two cultivars were used for validating the curve. The Nc dilution curve was validated for N-limiting and non-N-limiting growth conditions and there was good agreement between estimated and observed values. The N nutrition index (NNI) ranged from 0.41 to 1.25 and the accumulated plant N deficit (Nand) ranged from 60.38 to –17.92 kg ha?1 during the growing season. The relative grain yield was significantly affected by NNI and was adequately described with a parabolic function. The Nc curve based on LAI can be adopted as an alternative and more rapid approach to diagnose plant N status to support N fertilization decisions during the vegetative growth of winter wheat in Guanzhong Plain in Northwest China.

MULTIPLICITY OF POSITIVE SOLUTIONS FOR SINGULAR ELLIPTIC SYSTEMS WITH CRITICAL SOBOLEV-HARDY AND CONCAVE EXPONENTS

In this paper,we consider a singular elliptic system with both concave non-linearities and critical Sobolev-Hardy growth terms in bounded domains.By means of variational methods,the multiplicity of positive solutions to this problem is obtained.

SOLUTIONS FOR A NONHOMOGENEOUS ELLIPTIC PROBLEM INVOLVING CRITICAL SOBOLEV-HARDY EXPONENT IN R^N

For the following elliptic problem {-△u-μu/｜x｜^2=｜u｜^2^＊（s）-2u/｜x｜^s＋h（x）, on R^N u∈D^1,2（R^N）, N≥3, 0≤μ〈μ^-=（N-2）^2/4, 0≤s〈2, where 2^＊（s）=2（N-s）/N-2 is the critical Sobolev-Hardy exponent, h（x） ∈ （D^1,2（R^N））^＊, the dual space of （D^1,2（R^N））, with h（x）≥（≠）0. By Ekeland＇s variational principle, subsuper solutions and a Mountain Pass theorem, the authors prove that the above problem has at least two distinct solutions if ｜｜h｜｜＊〈CN,sAs^N-s/4-2s（1-μ/μ）^1/2, CN,s=4-2s/N-2（N-2/N＋2-2s）^N＋2-2s/4-2s and As = inf u∈D^1,2（R^N）／{0}∫R^N（｜△↓u｜^2-μu^2/｜x｜^2）dx/（∫R^N｜u｜^2^＊（s）/｜x｜^sdx）^2/2^＊（s）.

EXISTENCE OF MULTIPLE SOLUTIONS FOR SINGULAR QUASILINEAR ELLIPTIC SYSTEM WITH CRITICAL SOBOLEV-HARDY EXPONENTS AND CONCAVE-CONVEX TERMS

The main purpose of this paper is to establish the existence of multiple solutions for singular elliptic system involving the critical Sobolev-Hardy exponents and concave-convex nonlinearities. It is shown, by means of variational methods, that under certain conditions, the system has at least two positive solutions.

TWO DISJOINT AND INFINITE SETS OF SOLUTIONS FOR AN ELLIPTIC EQUATION INVOLVING CRITICAL HARDY-SOBOLEV EXPONENTS

In this paper,by an approximating argument,we obtain two disjoint and infinite sets of solutions for the following elliptic equation with critical Hardy-Sobolev exponents■whereΩis a smooth bounded domain in RN with 0∈?Ωand all the principle curvatures of?Ωat 0 are negative,a∈C1(Ω,R*+),μ>0,0<s<2,1<q<2 and N>2(q+1)/(q-1).By2*:=2N/(N-2)and 2*(s):(2(N-s))/(N-2)we denote the critical Sobolev exponent and Hardy-Sobolev exponent,respectively.

MULTIPLICITY OF POSITIVE SOLUTIONS FOR A NONLOCAL ELLIPTIC PROBLEM INVOLVING CRITICAL SOBOLEV-HARDY EXPONENTS AND CONCAVE-CONVEX NONLINEARITIES

In this article,we study the following critical problem involving the fractional Laplacian:{(−Δ)^α/2u−γu/|x|^α=λ|u|^q−2/|x|^s+|u|^2^∗α^(t)−2u/|x|^t in Ω,u=0 in R^N∖Ω,whereΩ⊂R^N(N>α)is a bounded smooth domain containing the origin,α∈(0,2),0≤s,t<α,1≤q<2,λ>0,2α^*(t)=2(N-t)/N-αis the fractional critical Sobolev-Hardy exponent,0≤γ<γH,and γH is the sharp constant of the Sobolev-Hardy inequality.We deal with the existence of multiple solutions for the above problem by means of variational methods and analytic techniques.

INFINITELY MANY SOLUTIONS FOR A SINGULAR ELLIPTIC EQUATION INVOLVING CRITICAL SOBOLEV-HARDY EXPONENTS IN R^N

In this article, we study the existence of multiple solutions for the singular semilinear elliptic equation involving critical Sobolev-Hardy exponents -△μ-μ｜x｜^2^-μ=α｜x｜^s^-｜μ｜^2＊（s）-2u＋βα（x）｜u｜^r-2u,x∈R^n. By means of the concentration-compactness principle and minimax methods, we obtain infinitely many solutions which tend to zero for suitable positive parameters α,β.

EXISTENCE OF POSITIVE SOLUTIONS TO QUASI-LINEAR EQUATION INVOLVING CRITICAL SOBOLEV-HARDY EXPONENT

This paper is concerned with the quasi-linear equation with critical Sobolev-Hardy exponent whereΩ(?)RN(N(?)3)is a smooth bounded domain,0∈Ω,0(?)s<p,1<p<N,p(s):=p(N-s)/N-p is the critical Sobolev-Hardy exponent,λ>0,p(?)r<p,p:=Np/N-p is the critical Sobolev exponent,μ>,0(?)t<p,p(?)q<p(t)=p(N-t)/N-p.The existence of a positive solution is proved by Sobolev-Hardy inequality and variational method.

基于改进Critic权重法的冲击地压危险等级预测方法

屯宝煤矿WⅡ02040501工作面受断层构造影响,回采期间大能量微震事件频发,为提高工作面采掘期间大能量微震事件的预警准确率,通过多元Logistic回归模型,从微震日能量/频次等监测指标中筛选出了微震日频次、频次变化量、日平均能量3个关键预警指标,基于Critic改进权重法建立了各预警指标与冲击地压危险等级的耦合公式,并在WⅡ02040501工作面进行了工程验证。研究结果表明:基于微震能量四分位数间距法划分的微震“大能量”事件临界值,可有效判识具有诱冲危险性的大能量微震事件;基于日频次、频次变化量、日平均能量3个预警指标确定的耦合公式,对大能量微震预警准确率达到了80%,可提高冲击地压防治措施的针对性和有效性。

基于改进CRITIC-VIKOR法的地铁车站运营韧性评价方法

地铁车站运营韧性具有多维性和复杂性。为了准确可靠地评价地铁车站运营韧性水平,提出了1种基于改进CRITIC-VIKOR法的评价方法。基于韧性理论和地铁车站运营特点,明确了地铁车站运营韧性的概念,并阐述了其压力、状态、响应3个维度的内涵。分析地铁车站运营中人、机、环、管这4个方面的关键要素,构建了8个一级指标。通过文献分析,建立了26个二级评价指标。通过采用标准差系数法衡量评价指标,并计算相关系数的绝对值,对CRITIC法进行改进,从而更加合理地给评价指标赋权,并结合VIKOR方法,提出了1种新的地铁车站运营韧性评价模型。对江苏省苏州市地铁4号线的同里站、流虹站、南门站进行实证分析,通过李克特量表收集相关数据,计算得到了26个评价指标的权重和3个车站的群体效用值、个体遗憾值、决策指标值,从而对地铁车站运营韧性进行量化分析和排序。与优序图法、层次分析法、熵值法等赋权方法相比,改进CRITIC法的偏差范围最小,为2%~40%,26个指标累计偏差最小,为553%。研究结果表明:在3个维度韧性中,压力韧性、状态韧性和响应韧性的权重分别为59.74%,21.48%,18.78%。在3个车站中,流虹站的运营韧性最高,其次是同里站和南门站。本文构建的评价模型能够为更加准确地评价地铁车站运营韧性提供理论支持。

基于动态CRITIC赋权的中国金融压力指数构建与金融风险识别

合理测度和准确识别金融市场风险,对于稳定经济、有效防范金融风险意义重大。依据中国金融市场特征,本文采用动态CRITIC法计算权重并建立金融压力指数测度模型,通过非参数统计核密度法和B-N数据分解法对金融压力指数的分布和金融风险状态进行估计与识别,采用马尔科夫区制转换模型检验高低风险转换概率,并与基于确定项进行识别的结果进行对比分析。研究表明:基于动态CRITIC赋权的金融压力指数更能反映金融市场的极端值和金融风险,随机冲击是影响我国金融压力指数的重要因素,两种金融风险识别方法均可识别金融风险状态且各有优势,研究中可以互为补充。今后应建立更加完善的风险测度指标体系,进一步完善监管制度,加强对金融风险的宏观审慎管理和防范。

NONTRIVIAL SOLUTION FOR A CLASS OF SEMILINEAR BIHARMONIC EQUATION INVOLVING CRITICAL EXPONENTS

In this article, the authors prove the existence and the nonexistence of nontrivial solutions for a semilinear biharmonic equation involving critical exponent by virtue of Mountain Pass Lemma and Sobolev-Hardy inequality.

Impact of disease severity on gastric residual volume in critical patients

AIM: To investigate whether illness severity has an impact on gastric residual volume (GRV) in medical critically ill patients. METHODS: Medical intensive care unit (ICU) patients requiring nasogastric feeding were enrolled. Sequential Organ Failure Assessment (SOFA) score was assessed immediately preceding the start of the study. Acute Physiology and Chronic Health Evaluation (APACHE) Ⅱ scores were recorded on the first, fourth, seventh, and fourteenth day of the study period. GRV was measured every 4 h during enteral feeding. The relationship be-tween mean daily GRV and SOFA scores and the correlation between mean daily GRV and mean APACHE Ⅱ score of all patients were evaluated and compared. RESULTS: Of the 61 patients, 43 patients were survivors and 18 patients were non-survivors. The mean daily GRV increased as SOFA scores increased (P < 0.001, analysis of variance). Mean APACHE Ⅱ scores of all patients correlated with mean daily GRV (P = 0.011, Pearson correlation) during the study period. Patients with decreasing GRV in the first 2 d had better survival than patients without decreasing GRV (P = 0.017, log rank test). CONCLUSION: GRV is higher in more severely ill medical ICU patients. Patients with decreasing GRV had lower ICU mortality than patients without decreasing GRV.

Determining nitrogen status and quantifying nitrogen fertilizer requirement using a critical nitrogen dilution curve for hybrid indica rice under mechanical pot-seedling transplanting pattern

Field experiments of nitrogen(N)treatment at five different application rates(0,75,150,225,and 300 kg ha^(-1))were conducted under pot-seedling mechanical transplanting(PMT)in 2018 and 2019.Two high-quality and high-yielding hybrids of indica rice,Huiliangyou 898 and Y Liangyou 900,were used in this study.The N nutrition index(NNI)and accumulated N deficit(N_(and)),used to assess the N nutrition status in real-time,were calculated for the indica cultivars under PMT with a critical nitrogen concentration(N_(c))dilution model based on shoot dry matter(DM)during the whole rice growth stage.The relationships between NNI and N_(and) with relative yield(RY)were determined,and accurate N application schemes were developed for hybrids indica rice under PMT.The results indicated that high application rate of N-fertilizer significantly increased the concentrations of shoot DM and N in aboveground organs during the observed stages in the two cultivars for two years(P<0.05).The N_(c) dilution model of hybrid indica cultivars was N_(c)=4.02 DM^(-0.42)(R^(2)=0.97)combining the two cultivars under PMT.Root-mean-square error and normalized root-mean-square error of the curve verification were 0.23 and 10.61%,respectively.The NNI and Nand ranged from 0.58 to 1.31 and 109 to–55 kg ha^(-1),respectively,in the two cultivars for all N treatments.NNI showed a linear relationship with Nand during the entire growth stage(0.53<R^(2)<0.99,P<0.01).In addition,NNI showed a linear-plateau relationship with RY(0.73<R<0.92,P<0.01)throughout the observed stages.These results suggest that the models can accurately diagnose the N-nutrition status and support effective N-fertilizer management in real-time for hybrid indica rice under PMT.

基于CRITIC-VIKOR法的云南省水资源承载力综合评价

为衡量云南省经济、社会、生态发展协调程度,针对云南省水资源综合开发利用程度构建涵盖水资源、生态环境、经济社会的水资源承载力评价指标体系,采用CRITIC-VIKOR法对2004-2018年云南省和2018年云南省各地级市(自治州)水资源承载力进行综合评价。结果表明:2004-2018年云南省综合水资源承载力有所增大且具有改善潜力,水资源子系统和生态环境子系统的水资源承载力总体呈增大趋势,经济社会子系统水资源承载力最稳定且有明显提升空间;2018年云南省红河州、普洱市、丽江市、玉溪市、大理州的综合水资源承载力在各市(州)中位于前5位,综合水资源承载力评价值分别为0.0575、0.1019、0.1133、0.2076和0.2815;怒江州、临沧市、昭通市、保山市水资源综合承载力位于后4位,综合水资源承载力评价值分别为0.6345、0.8144、0.9081和0.9182。该研究对云南省水资源综合开发利用和保护具有参考意义。

Critical Value of CO of Forecasting Coal Spontaneous Combustion

CO has been used widely in the production process of colliery as an index gas to predict spontaneous combustion of coal. But in some collieries there are CO gas in the upper corner of the face all the times, sometime CO gas even exceeds the regulated critical index. This phenomenon is much more obvious in the fully-mechanized longwall face and fully-mechanized longwall and top-coal caving face. Although many measures of fire-proof and fire-extinguishing have been adopted, the flowing amount of CO gas can be only decreasd, but can not be eliminated completely. Using the different kinds of coal, the experiment of coal oxidation was made at the low temperature. The experiment indicates that some kinds of coal can produce CO under the condition of normal temperature oxidation, sometime the CO consistency is very high, and the intension of CO can be decreased with oxidation time prolonging. Selecting rational critical value of CO is the kev to predicting spontaneous combustion of coal correctly and reliably. The problem of selecting retional critical value of CO was studied. Finally, the amount of CO gas released by different kinds of coal was obtained under normal temperature condition.

Network Structure-Based Critical Bus Identification for Power System Considering Line Voltage Stability Margin

Voltage security assessment of power system is an important and all-inclusive aspect of power system operation and preventive control actions. Fast and accurate detection of critical components of the power system is one essential approach for preventing the occurrence of voltage collapse phenomenon. Over the years, several approaches for voltage collapse point identification and prevention have been widely studied using the continuous power flow approach, minimum singular value of eigenvalues, Jacobian matrices, and power transfer concept. In this work, critical node (bus) identification based on power system network structure is proposed. In this approach, the power system is treated as a multidimensional graph with several nodes (buses) linked together by the transmission lines. An improved line voltage stability margin estimator which is based on active and reactive power changes in a power system is used as the weight of each transmission line and an adaptation of the degree of centrality approach is used to determine the criticality of the system buses. A comparative analysis with other bus voltage stability indices is presented to test the suitability of the proposed approach using the IEEE 14, 30, 57 and 118 bus test systems.