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.

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。

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-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。

Orientation-enhanced nonlinear optical properties and phase-conjugate reflective system of a novel Azobenzene doped polymer film

This paper reports that the nonlinear refractive index of a novel organic optical storage film doped azodiphenylamine polymer is measured by using the Z-scan technique. The nonlinear refractive index up to 3.7× 10^-6 cm^2/W induced by thermo-optical effect is obtained. It indicates that the sample has excellent optical non- linear properties. The physical mechanism of the great nonlinear optical effect is analysed and the optical conjugate characteristic is also discussed with degenerate four-wave-mixing. The phase conjugate wave diffracted from the formative refractive index grating in the sample is acquired and its equivalent reflectivity reaches about 22%. On this basis, the reflective wave phase-conjugated mirror system was designed, and the image aberration experienced in propagation in the storage experiment is corrected by using the system.

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.

Measuring Criticality of Raw Materials: An Empirical Approach Assessing the Supply Risk Dimension of Commodity Criticality

Providing a sustainable and reliable supply of raw materials at economic prices has become essential to industrialized economies. Therefore, the need for both economical and sustainable methods and strategies for the management of raw materials has been postulated to enable companies and economies to counteract dramatic effects of supply disruptions, or at least to provide early warnings. The relevant studies assign generic weights to different driving factors and therefrom derive criticality indexes. However, it often remains open how to interpret the resulting measures and how to apply them practically. Here we show that based on current commodity key figures, it is possible to empirically determine the risk for future price increases and fluctuations. Thus, we can identify future supply risks and incorporate their patterns into an empirically calibrated criticality measurement. To this end, we apply the well-known compounding framework used by many companies for their financial planning, calculating net present values and volatility from the predicted future price development. To calibrate each resource specific model, we perform extended regression analyses on our compounded criticality index from time series of 42 (out of about 60 industrially relevant) chemical elements. The analysis thereby covers 9 driving factors for criticality and a 40-year time span. Our results suggest a fundamental modification of current practices for criticality assessment, in particular by scaling the criticality measure to correspond with the net present value of future commodity expenses and future volatility.

The Criticality Indices of Activities in PERT

In this paper, we present a direct computing method of the Criticality Index (CI) of the activities in PERT networks. The method is no needed for determining CI of all the paths in a PERT network, and the CI of all the activities can be estimated by computing CI of a small portion of the activities. We give the series of conclusions and computation formulas for computing the CI of activities, and the computing algorithm for the above mentioned conclusions has been applied to large size PERT network. The results are found to be very close to those obtained by extensive Monte Carlo sampling.

Identification of Critical Lines in Power System Based on Optimal Load Shedding

Based on risk theory, considering the probability of an accident and the severity of the sequence, combining N-1 and N-2 security check, this paper puts forward a new risk index, which uses the amount of optimal load shedding as the severity of an accident consequence to identify the critical lines in power system. Taking IEEE24-RTS as an example, the simulation results verify the correctness and effectiveness of the proposed index.

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。

Nutrient Loss from Farmland:Research on and Application of Phosphorus Index Method

Phosphorus index method is an effective method to assess the risk of phosphorus loss,identify the critical source areas and reasonably control the agricultural non-point source pollution.The researches on phosphorus index assessment method have been started earlier in foreign countries.Currently,phosphorus index assessment method has been widely used in the United States and European countries through continuous development and improvement.However,the domestic research on non-point source phosphorus pollution assessment has just started,and the phosphorus index method that is suitable for the characteristics of agriculture in China has not yet been established.This paper summarizes and analyzes systematically the related research advances in phosphorus index method at home and abroad,and illustrates the issues presented in phosphorus index method.In addition,the researches on and application of phosphorus index method in China are discussed.

基于AHP-CRITIC的电梯安全性评估

针对电梯安全评估方法中指标权重主观性大的问题,为提高评估结果的科学性,综合AHP法、CRITIC法和模糊综合评价理论,建立了电梯安全性评估模型。从设备情况、使用情况、人员管理3个方面出发,构建了电梯安全性评估指标体系。采用AHP法,根据专家经验构造判断矩阵,得到指标的主观权重。采用CRITIC法,计算同一指标的对比强度和指标间的冲突性,得到指标的客观权重。通过加权求和的方式,兼顾主客观权重,得到指标的综合权重。基于模糊综合评价法,应用"升半梯形分布"对各级指标构造模糊评估矩阵,并量化评估结果向量。以南京市某电梯为实例,应用该模型得出此电梯的安全值为68.8,安全等级为"较安全",与此电梯的实际情况相符;并与其他方法所得的评估结果进行比较,进一步验证了该模型的正确性和有效性。

基于CRITIC赋权法的细支烟物理指标综合质量评价研究

目的为建立细支烟物理指标综合质量评价方法,以客观评价细支烟卷制过程中的质量稳定性。方法以某细支卷烟质量、圆周、长度、吸阻和总通风率为基础,利用CRITIC赋权法计算各物理指标的客观权重,并结合其技术标准,计算出每支细支烟的综合得分以及各班组、机台生产细支烟的综合得分和过程绩效指数,建立细支烟物理指标综合质量评价方法。结果基于CRITIC赋权法计算,细支烟质量、圆周、长度、吸阻和总通风率权重系数分别为0.152、0.147、0.243、0.182和0.276,合格烟支的综合得分≥60分,不合格烟支的综合得分<60分,班组抽检烟支的综合得分与合格率呈线性正相关(R2=0.9569),客观地反映了细支烟主观扣分偏好和物理质量的整体水平。结论基于CRITIC赋权法建立的细支烟物理指标综合质量评价方法,能客观评价班组和机台的卷烟卷制综合质量水平,及时发现细支烟卷接包装过程中存在的质量问题。

基于CRITIC权的污染指数法在清潩河水质评价中的应用

根据污染指数法进行水质评价的基本流程和CRITIC法确定指标权重的原理,构建了基于CRITIC权污染指数法的河流水质评价模型,并以清潩河流域许昌段断面的河流水质评价为例,根据流域断面实测水质数据,选取COD和氨氮作为代表性评价因子进行水质评价,得到2011~2014年清潩河流域东城区107国道断面总污染指数的变化趋势以及四个断面的污染指数评价等级。结果表明,清潩河流域许昌段断面水质状况不容乐观,东城区107国道断面污染指数总体呈上升趋势,主要干流断面水质均为劣Ⅴ等级。

基于AHP-CRITIC权重分析法结合正交设计法优选降脂方冲泡条件的研究

目的:研究降脂方代茶饮的最佳冲泡条件。方法:以总黄酮、总生物碱、蒽醌类成分的含量以及浸膏得率作为评价指标,采用AHP-CRITIC混合加权法确定各指标权重系数以得出综合评分,结合正交试验优选降脂方冲泡条件中的冲泡时间、次数及加水量,并加以验证。结果:以AHP-CRITIC混合加权法确定的权重系数较为合理,优选的冲泡条件为20倍量的沸水冲泡3次,每次40 min。验证试验综合评分均值为97.788,RSD为1.09%(n=3)。结论:AHP-CRITIC混合加权法可用于降脂方冲泡条件优选多指标权重的建立,优选的冲泡条件经验证,合理、稳定,重复性好。