NITROGEN NUTRIENT MECHANISM IN SECONDARY SUCCESSION PROCESS OF THE MIXED BROAD-LEAVED/ KOREAN PINE (PINUS KORAIENSIS) FOREST

Chemical and biochemical analysis methods were used to monitor the vedations of nitrogen nutrient among the dominance trees species in secondary succession process of the mixed broad - leaved/Korean pine forest on Changbai Mountains, Northeast China. Amounts of total nitrogen, anunonium and NRA in soils of virgin broad-leaved/Korean pine forest which is in climax were higher than those of secondary birch forests those are in succession Stage. The amount of nitrate was in the other hand. In climax, dominance trees species are tolerant mesophytic trees such as Pinus Koraiensis, Tilia amurensis, Acer mono and also Fraxinus mandshurica, they are all ammonium + nitrate adapted species, but they show a preference for the anunonium rather than those of the pioneer trees species in secondary birch forest, such as Populus davidiava and Betula platyphylla. Because they have more ammonium in their leaves and roots, especially Pinus koraiensis. Populus davidvana and Betula plaaphlla are intolerant trees, amounts of nitrate and total nitrogen is higher in their leaves and roots and also NRA in their leaves, so they preference for the nitrate rather than the others.In secondary birch forest, the regeneration trees species adapt their nitroggn nutrient to the variation of nitrogen nutrient situation in soil, finally they could survival well and the secondary birch forest would succession to climax. In climax, dominance trees species adapt their Nitrogen nutrient to the situation in soil and there are not strong competition in nitrogen nutrient among them, so they can coexist well and keep the climax as stable vegetation.

Development of a Process for Formulating Infant Flours from the Almonds of <i>Treculia obovoidea, Terminalia catappa</i>Linne as well as <i>Ipomoea batatas</i>Lam Leaves

In response to the malnutrition problem affecting children in Congo Brazzaville, we made three cooking-type infant flours from Treculia obovoidea, Terminalia catappa L. almonds and Ipomoea batatas L. leaves. The nutritional quality of the three infant flours we developed indicates 11.07% - 12.47% protein content, 9.92% - 14.87% fat content, 58.85% - 68.06% carbohydrate content, 1.50% - 2.18% ash and an energy intake varying between 399.84 and 439.37 Kcal. Functionally, our prepared flours have a water absorption capacity between 219.05 and 317.86 mL/g, an oil absorption capacity of 0.19 mL/g, a water solubility index varying from 29.66 - 41.03 and a swelling capacity of 250% - 320%.

THE JOINT DISTRIBUTIONS OF SOME ACTUARIAL DIAGNOSTICS FOR THE JUMP-DIFFUSION RISK PROCESS

In this article, the joint distributions of several actuarial diagnostics which are important to insurers＇ running for the jump-diffusion risk process are examined. They include the ruin time, the time of the surplus process leaving zero ultimately （simply, the ultimately leaving-time）, the surplus immediately prior to ruin, the supreme profits before ruin, the supreme profits and deficit until it leaves zero ultimately and so on. The explicit expressions for their distributions are obtained mainly by the various properties of Levy process, such as the homogeneous strong Markov property and the spatial homogeneity property etc, moveover, the many properties for Brownian motion.

Some Applications of the Poisson Process

The Poisson process is a stochastic process that models many real-world phenomena. We present the definition of the Poisson process and discuss some facts as well as some related probability distributions. Finally, we give some new applications of the process.

基于改进YOLOv7-tiny的番茄叶片病虫害检测方法

为解决自然环境中番茄叶片病虫害检测场景复杂、检测精度较低,计算复杂度高等问题,该研究提出一种SLPYOLOv7-tiny的深度学习算法。首先,将主干特征提取网络中部分3×3的卷积Conv2D(2D convolution)改为分布偏移卷积DSConv2D(2D Depthwise Separable Convolution),以减少网络的计算量,并且使计算速度更快,占用内存更少;其次,将无参数注意力机制(parameter-free attention module,SimAM)融合到骨干特征提取网络中,加强模型对病虫害特征的有效提取能力和特征整合能力;最后,将原始YOLOv7-tiny的CIOU损失函数,更替为Focal-EIOU损失函数,加快模型收敛并降低损失值。试验结果表明,SLP-YOLOv7-tiny模型整体识别精准度、召回率、平均精度均值mAP_(0.5)(IOU阈值为0.5时的平均精度)、mAP_(0.5~0.95)(IOU阈值从0.5到0.95之间的平均精度)分别为95.9%、94.6%、98.0%、91.4%,与改进前YOLOv7-tiny相比,分别提升14.7、29.2、20.2、30个百分点,同时,计算量降低了62.6%。与YOLOv5n、YOLOv5s、YOLOv5m、YOLOv7、YOLOv7-tiny、Faster-RCNN、SSD目标检测模型相比,mAP_(0.5)分别提升了2.0、1.6、2.0、2.2、20.2、6.1和5.3个百分点,而计算量大小仅为YOLOv5s、YOLOv5m、YOLOv7、Faster-RCNN、SSD的31.5%、10.6%、4.9%、4.3%、3.8%。结果表明SLP-YOLOv7-tiny可以准确快速地实现番茄叶片病虫害的检测,且模型较小,可为番茄叶片病虫害的快速精准检测的发展提供一定的技术支持。

Feature extraction of welding defect based on machine vision

There are many flaws in welding images such as noise, low contrast, and blurred edges, which affect feature extraction from welding defect regions and impede classification and recognition of welding defects. To deal with the complexity of welding defect images, this paper proposes an effective method for extracting the features of welding defect regions. Firstly, image preprocessing, image segmentation and image background removal are carried out to a welding image in order to extract welding defect region; and then an 8-connected-component labeling method is used to mark defect regions. Finally, it extracts geometric characteristic parameters including perimeter, area, circularity and others. The experimental result shows that the method proposed in the paper can accurately extract the features of welding defect regions. It has good adaptability and practicability.

Orthogonal Test Optimization of Extraction Technology of Total Fla-vonoids from Fruits and Leaves of Prunus mume Sieb. et Zucc. and Its in Vitro Anti-oxidation Activity

[Objectives]To optimize the extraction technology of total flavonoids component,and investigate its in vitro anti-oxidation activity.[Methods]The single factor was inspected firstly. By orthogonal experiment,the best extraction conditions of total flavonoids from fruits and leaves of P. mume Sieb. et Zucc. were determined,and reducing ability of the extracted total flavonoids and its DPPH and ABTS scavenging abilities were explored. [Results] The best extraction technology conditions: solid-liquid ratio of 1∶ 50,ethanol concentration of 50%,extraction time of 2. 5 h,extraction temperature of 85 ℃,two-time extraction. By detecting DPPH and ABTS scavenging abilities of total flavonoids,the anti-oxidation activity of the total flavonoids from fruits and leaves of P. mume Sieb. et Zucc. was analyzed and evaluated. [Conclusions]Fruits and leaves of P. mume Sieb. et Zucc. had a certain in vitro anti-oxidation activity,and heat reflux extraction method of its total flavonoids had high extraction rate and simple and convenient operation,which had some practical value.

Evolutionary artificial neural network approach for predicting properties of Cu-15Ni-8Sn-0.4Si alloy

A novel data mining approach,based on artificial neural network(ANN) using differential evolution(DE) training algorithm,was proposed to model the non-linear relationship between parameters of aging processes and mechanical and electrical properties of Cu-15Ni-8Sn-0.4Si alloy.In order to improve predictive accuracy of ANN model,the leave-one-out-cross-validation (LOOCV) technique was adopted to automatically determine the optimal number of neurons of the hidden layer.The forecasting performance of the proposed global optimization algorithm was compared with that of local optimization algorithm.The present calculated results are consistent with the experimental values,which suggests that the proposed evolutionary artificial neural network algorithm is feasible and efficient.Moreover,the experimental results illustrate that the DE training algorithm combined with gradient-based training algorithm achieves better convergence performance and the lowest forecasting errors and is therefore considered to be a promising alternative method to forecast the hardness and electrical conductivity of Cu-15Ni-8Sn-0.4Si alloy.

Optimization of Extraction Technology and Determination of Content of Total Phenols of Leaves in Acanthopanax giraldii Harms

[Objectives] To determine the optimum extraction technology for total phenols of leaves in Acanthopanax giraldii Harms.[Methods]The single factor test and orthogonal design were adopted to study the extraction technology for total phenols of leaves in Acanthopanax giraldii Harms. [Results]The optimum extraction conditions were determined as follows: extraction solvent( 70% methanol),solid-liquid ratio( 1∶ 35),and reflux extraction time( 60 min). Under these conditions,the yield of crude extract from total phenols of leaves in Acanthopanax giraldii Harms was 38. 67 mg/g.[Conclusions] The technology was simple,and of low cost and high extraction rate,suitable for the extraction of total phenols of leaves in Acanthopanax giraldii Harms.

主观题自动评判算法研究综述

在教育教学中,试卷评判是教师获取学生知识点掌握情况的重要途径。然而,试题评分是一个耗时的过程,主观题的评判更需要阅卷人认真、投入、细致地审阅,需要耗费大量精力。要减轻教师工作压力,提高主观题评判的效率,基于人工智能的自动评判技术非常重要,其中主观题的自动评判是难点。随着机器学习和深度学习等技术在自然语言处理领域的发展,主观题自动评判技术有了较大进展。文中将主观题分为常规型和开放型两类进行文献梳理,总结主观题自动评价的标准和公开数据集,归纳涉及的方法和技术路线,并对主观题自动评判技术未来的研究方向进行总结和展望。

辽东楤木叶总皂苷提取工艺研究

以总皂苷提取率、两种质量标志性皂苷成分的提取率为指标探索辽东楤木叶药材中皂苷的提取工艺。分别考察药材浸泡达饱和的时间、回流提取时乙醇溶液用量、提取时间、提取次数以及乙醇溶液浓度对辽东楤木叶皂苷提取率的影响,并采用正交实验法对辽东楤木叶总皂苷的提取工艺进行优化。结果表明,药材经乙醇水溶液浸泡3h以上达到吸收饱和;加8倍量的70%乙醇水溶液回流提取3次,每次2.5h,所得的辽东楤木叶总皂苷提取率及两种指标性皂苷提取率均较高。

响应面法对金银花叶总黄酮与绿原酸同步萃取工艺的优化

采用响应面法,对加压辅助溶剂同步萃取金银花叶总黄酮和绿原酸的工艺进行了优化。在单因素试验的基础上,综合评价总黄酮和绿原酸的得率“OD值”作为因变量,通过响应面法优化了液料比、萃取压力、溶剂体积分数、萃取温度和萃取时间。结果表明,优化后的加压辅助溶剂同步萃取工艺参数为:液料比26.5 mL/g,萃取压力3.1 MPa,溶剂体积分数60.5%,萃取温度90.3℃,萃取时间32 min。该工艺条件下,从金银花叶中萃取总黄酮得率为205.3 mg/g,绿原酸得率为24.5 mg/g, OD值与理论预测值的相对误差为1.0%。

沙棘叶中提取黄酮类化合物工艺影响因素研究

本文以乙醇/水溶液作为提取剂对沙棘叶中的黄酮类化合物进行提取,考察了乙醇浓度、提取温度、提取时间对提取效率的影响,并对实验数据进行了化学动力学模型拟合。实验结果表明,脱脂沙棘叶粉末中黄酮类化合物提取的最佳条件为乙醇质量分数60%,提取温度65℃,提取时间60 min,此条件下黄酮类化合物的提取效率最高为4.12%(质量分数)。化学动力学拟合结果表明,二级动力学模型与黄酮类化合物提取工艺数据的拟合度较高,平均相对偏差为±3%。本研究能为推动沙棘提取黄酮类化合物的产业化提供基础的数据支持。

不同润叶和复烤强度对上部烟叶质量的影响

以云烟87上部烟叶为研究对象,以颜色深浅度、色度、均匀度、油分、常规化学成分和感官质量为评价指标,开展了不同润叶和复烤强度对上部烟叶质量的影响研究。结果表明,随着润叶强度的增加,润叶后烟叶颜色逐渐加深,色度偏向深橘黄,均匀度逐渐变差,油分增加;复烤后烟叶颜色变浅,色度向柠檬黄转变,均匀度提升,油分降低,较高温度复烤的烟叶均匀度和油分优于低温复烤;随润叶强度增加烟叶烟碱和总糖含量逐渐升高,复烤后其含量逐渐下降;随润叶强度增加润叶后的感官质量逐渐降低,低水分润叶下随复烤温度增加感官质量提升,高水分润叶下随复烤温度增加感官质量下降。综合来看,低水分润叶(W15%)和较高温度复烤(T 70℃)更有利于上部烟叶质量的形成。

艾叶总黄酮提取工艺优化和抗氧化活性的初步探究

本试验运用正交试验法对优化艾叶黄酮的提取工艺及抗氧化活性进行了初步探究。经过试验得出,艾叶黄酮的最佳提取工艺为80%乙醇溶液浸取1∶25(g/mL)料液比的艾叶粉末4 h并超声提取50 min,提取率为3.53%。艾叶黄酮提取液浓度与总还原能力呈正相关关系,当艾叶黄酮质量浓度为1 mg/mL时,对DPPH·和·OH的清除率分别为96.35%和97.49%,具有较强的抗氧化活性。

一测多评法同时测定连翘和连翘叶中多种成分

目的:建立同时测定连翘和连翘叶中绿原酸、芦丁、连翘酯苷B、连翘酯苷A、松脂醇-β-D-葡萄糖苷、连翘苷和连翘酯素7种成分的一测多评(QAMS)方法。方法:采用HPLC法,以连翘苷为内参物,分别建立连翘苷与其余6种成分的相对校正因子(RCF),并计算含量,实现一测多评;同时采用外标法测定该7种成分的含量,比较两种方法的差异,验证QAMS的准确性和可行性。结果:在不同实验条件下,RCF重现性良好,13批样品中该7种成分的一测多评值和外标法测定值无显著差异。结论:QAMS法可用于连翘和连翘叶的定量分析。

芹椒酱制作工艺优化及品质分析

为了提高芹菜叶的利用率,开发一种新的蔬菜酱制品。以新鲜芹菜叶、青红椒等作为主要原料,辅以大蒜、薄荷等进行芹椒酱的研制。在单因素试验的基础上,采用模糊数学感官评定法和响应面优化法对影响芹椒酱的白砂糖添加量、盐添加量、鸡精添加量和植物油添加量进行优化。结果表明,在矿泉水25%、芹菜叶30%、青椒20%、红椒10%、大蒜12.5%和薄荷叶2.5%的基础配方上,当白砂糖添加量5.5%、盐添加量3.5%、鸡精添加量1.5%、植物油添加量35%时,芹椒酱的感官评分最高,达到95.21分。此时芹椒酱的蛋白质、氨基酸态氮、维生素含量分别为8.64 g/100 g、4.96 g/100 g、67.24 mg/100 g,微生物检测结果符合国家标准要求。该研究为酱制品的开发提供了一定理论依据。

响应面法优化碱法提取狐臭柴叶多糖工艺及生物活性研究

优化狐臭柴叶碱溶性多糖(PLAP)提取工艺,探讨PLAP的体外抗氧化和抗肿瘤活性。采用狐臭柴叶经酸提取法提取的残渣为原料,在单因素基础上,利用响应面优化PLAP的提取工艺,通过抗氧化实验和抗肿瘤实验对PLAP的体外生物活性进行研究。结果表明:PLAP最佳提取工艺为:料液比1∶50 g/mL、NaOH浓度为0.25 mmol/L、提取时间110 min、此条件下PLAP提取率为(11.80±0.50)%。PLAP有较强的抗氧化活性,对DPPH自由基、羟基自由基和ABTS自由基清除率IC 50值分别为12.38、3.22和0.18 mg/mL。同时细胞实验表明,PLAP在一定范围内抑制A549细胞和HepG2细胞的增殖与迁移,呈现剂量效应关系。本文为狐臭柴资源的充分开发、临床应用提供理论依据。

桑叶抑制脂肪酶活性组分提取工艺优化及其成分分析

本文在单因素实验的基础上,结合响应面分析法考察原料质量浓度、乙醇体积分数、超声功率、提取温度和提取时间等因素对桑叶提取物抑制脂肪酶活性的影响,优化桑叶抑制脂肪酶活性组分的超声波辅助提取工艺,并采用超高效液相色谱-四级杆-飞行时间高分辨质谱技术(Ultra-high Performance Liquid Chromatography-Quadrupole-Time of Flight High Resolution Mass Spectrometry,UPLC-Q-TOF HRMS)对桑叶提取物活性成分进行检测分析。结果表明,桑叶抑制脂肪酶活性组分的最佳提取工艺参数为原料质量浓度0.05 g/mL、乙醇体积分数70%、超声功率195 W、提取温度31℃、提取时间40 min,在此条件下测得桑叶提取物脂肪酶抑制率为39.68%。共鉴定出了1067种化合物,其中黄酮和酚酸类占比最高,分别含有203和201种化合物,这些化合物可能是桑叶提取物抑制脂肪酶活性的物质基础。本研究优化桑叶超声波辅助提取工艺,针对性地提高桑叶抑制脂肪酶活性组分的提取效率,并分析桑叶抑制脂肪酶活性的主要成分,可为桑叶在改善脂质代谢方面的功能性应用及健康食品研发提供参考。

黄芩茎叶葡萄糖醛酸水解酶提取工艺、酶学性质、实际应用研究

目的研究黄芩茎叶葡萄糖醛酸水解酶(sbslGUS)提取工艺、酶学性质、实际应用。方法在单因素试验基础上,以粒度、加水量、提取时间、提取次数为影响因素,酶活性为评价指标,正交试验优化提取工艺。分析底物(黄芩苷)浓度与酶解速度的关系,计算V_(max)、K_(m),考察pH值、温度、金属离子对酶活性的影响,评价pH稳定性、热稳定性。sbslGUS酶解黄芩苷以制备黄芩素,考察pH值、温度、反应时间、底物初始浓度、加酶量对转化率的影响。结果最优提取工艺为粒度40目,加水量10倍,提取时间15 min,提取次数3次。酶解符合酶促反应动力学,K_(m)为0.0063 mol/L,V_(max)为70.42μmol/h,在pH值6.0、温度45℃、金属离子100 mmol/L Cu2+下酶活性最强,sbslGUS在pH值4.0~7.0、温度4~30℃范围内稳定性良好。最优制备工艺为pH值6.0,温度45℃,反应时间12 h以上,底物初始浓度67.2 mmol/L,加酶量1 mL/0.269 mmol黄芩苷,转化率为97.83%。结论sbslGUS酶解效率高,条件温和,可为获取黄芩素提供简便的制备方法,并且拓展了黄芩茎叶应用途径。