Construction of Anti-breaking Models of the Main Veins of Flue-cured Tobacco Leaves and Principal Component Analysis

[Objective] This study aimed to explore the related mechanisms of the breaking of flue-cured tobacco leaves. [Method] Anti-breaking models of the main veins of flue-cured tobacco leaves were constructed for principal component analysis on the anti-breaking index, leaf traits and cellulose contents. [Result] The results showed that the growth traits had certain relevance with the cellulose contents while the leaf weight assumed a significant negative correlation with the anti-breaking index, indicating that the heavier the leaf weight was, the weaker the anti-breaking capacity of flue-cured tobacco would be; the cross-sectional area of main veins and the cellulose contents had shown a positive correlation with the anti-breaking index, indicating that the thicker the main vein of flue-cured tobacco was, the higher the cellulose contents would be, and the stronger the anti-breaking capacity of flue-cured tobacco leaves would be. [Conclusion] This study provided theoretical basis and reference to improve tobacco production and enhance the quality of flue-cured tobacco.

Effects of acrous gramimeus and its main component alpha-asarone on the reactivity and convulsive threshold of immature rats to electric stimulation

BACKGROUND： The traditional Chinese medicine acrous gramimeus is the dry rhizome of Acrous gramimeus Soland, a kind of Araceae familial perennial herb, which has a sedation action, anticonvulsant and antiepileptic effect. Its effective component has not been known yet, and α-asarone, the major component of the volatile oil extracted from acrous gramineus, has been supposed to play a necessary role in it. OBJECTIVE： To explore the effects of acrous gramimeu and α-asarone on the reactivity and convulsive threshold to electric stimulation in immature rats, furthermore, attempt to definitize the anticonvulsant effect of α-asarone. DESIGN： A randomized controlled study.SETTINGS： Department of Pediatrics, First Hospital of Jilin University; Department of Histology and Embryology, School of Basic Medical Sciences of Jilin University; Department of Neurology, First Clinical Hospital affiliated to Harbin Medical University; Department of Internal Medicine, Children＇s Hospital of Changchun City. MATERIALS ： Seventy 3-week immature Wistar rats （either males or females） of 34-40 g were used. Acrous gramimeu （1 g/bag, the content of α-oasarone was 0.046 26%-0.070 16%） with the batch number of 0307113 was provided by Tianjiang Medicine Company Limited, Jiangyin City. α-asarone tablet （60 mg per tablet） with the batch number of 030219 was provided by Tianwei Pharmaceutical Factory, Shenyang City. α-asarone injectable preparation （2 mL per piece） with the batch number of 030105 was provided by Shuanghe Medicine Limited Company, Beijing City. METHODS ： The experiments were carried out in the Neurological Laboratory of the First Hospital of Jilin University between August and October in 2004.① The 70 rats were randomly divided into intragastric subset and intraperitoneal subset. The intragastric subset included four groups of control, phenobarbital sodium, acrous gramimeu and α-asarone; the intraperitoneal subset included three groups of control, phenobarbital sodium and α-asarone. There were 10 rats per group. ② In the intragastric subset, different group was treated with saline （1 mL for each time, phenobarbital sodium （18 mg/kg per day）, acrous gramineu （2 350 mg/kg per day） and α-asarone （29 mg/kg per day） respectively twice every day for 5 days. In the intraperitoneal subset, different group was treated with saline （0.5 mL）, phenobarbital sodium （29 mg/kg） and α-asarone （2.9 mg/kg） respectively. ③ Before and after administration for 5 days in the intragastric subset as well as before and after administration for about 1 hour in the intraperitoneal subset respectively, the rats were given electric stimulation with the NIHOM KOMDEM multifunctional electrophysiological recorder, and the reactivity and convulsive threshold to electric stimulation of the rats were recorded. MAIN OUTCOME MEASURES： The reactivity and convulsive threshold to electric stimulation in immature rats were compared. RESULTS： All the rats were involved in the analysis of results. ① Results for intragastric administration： Before intragastric administration, there were no obvious differences in the reactivity and convulsive threshold to electric stimulation among the groups （P 〉 0.05）. After intragastric administration for 5 days, the reactivity and convulsive threshold to the electric stimulation had no obvious changes in the control group, but those were significantly higher than before administration in the drug administration groups （t=-3.317-7.401, P 〈 0.01）, which were also obviously higher than those in the control group （t=3.027-8.941, P 〈 0.01）, and those in the acrous gramimeu group and α-asarone group were not markedly different from those in the phenobarbital sodium group. ② Results for intraperitoneal injection： Before intraperitoneal injection, the reactivity and convulsive threshold to the electric stimulation had no obvious differences among the groups. After the intraperitoneal injection for 1 hour, the reactivity and convulsive threshold to the electric stimulation had no obvious change in the control group, but those were significantly higher than before administration in the drug administration groups （P 〈 0.01）, which were also obviously higher than those in the control group （t=6.211-7.237, P 〈 0.01; t=4.085-5.633, P 〈 0.05）, and there was no marked difference between α-asarone group and phenobarbital sodium group （P 〉 0.05）.CONCLUSION ： ① As effective anticonvulsants, both acrous gramineu and α-asarone can enhance the reactivity and convulsive threshold of immature rats to electric stimulation. ② As one of the major effective components against convulsion of acrous gramineu, α-asarone is equivalent to phenobarbital sodium.

STRUCTURE OF MAIN COMPONENT IN PERFUME "ISO-E-SUPER"

Addition of myrcene and 3-methyl-3-penten-2-one followed by cyclization afforded perfume 'Iso-E-Super' with 2(?)-acetyl-2β,3β,8,8-tetramethyl-1,2,3,4,5,6,7,8-octalin as main component on the basis of its spectroscopic data.

Loss-of-Main Monitoring and Detection for Distributed Generations Using Dynamic Principal Component Analysis

In this paper, our previous work on Principal Component Analysis (PCA) based fault detection method is extended to the dynamic monitoring and detection of loss-of-main in power systems using wide-area synchrophasor measurements. In the previous work, a static PCA model was built and verified to be capable of detecting and extracting system faulty events;however the false alarm rate is high. To address this problem, this paper uses a well-known ‘time lag shift’ method to include dynamic behavior of the PCA model based on the synchronized measurements from Phasor Measurement Units (PMU), which is named as the Dynamic Principal Component Analysis (DPCA). Compared with the static PCA approach as well as the traditional passive mechanisms of loss-of-main detection, the proposed DPCA procedure describes how the synchrophasors are linearly auto- and cross-correlated, based on conducting the singular value decomposition on the augmented time lagged synchrophasor matrix. Similar to the static PCA method, two statistics, namely T2 and Q with confidence limits are calculated to form intuitive charts for engineers or operators to monitor the loss-of-main situation in real time. The effectiveness of the proposed methodology is evaluated on the loss-of-main monitoring of a real system, where the historic data are recorded from PMUs installed in several locations in the UK/Ireland power system.

Analysis on Main Traits of Spring Wheat Landraces in Tibet

In this study, 9 main traits of 774 spring wheat landraces in Tibet were investigated and analyzed. The results show that spring wheat landraces in Tibet have high plant height （with an average of 126.1 cm） and long growth period （with an average of 135.2 d）, with an average spike length of 9.5 cm, average effective tiller number per plant of 5.9, average spikelet number per spike of 19.9, average kernel number per spikelet of 3.5, average spikelet number per spike of 51.8, aver- age kernel weight per spike of 2.0 g, and average 1 000-grain weight of 38.1 g. Specifically, kernel number per spikelet of 2 landraces is larger than 6.0, spikelet number per spike of 2 landraces is larger than 100, kernel weight per spike of 2 landraces is larger than 4.0 g, 1 000-grain weight of 11 tandraces is larger than 50 g. There is abundant genetic diversity in those traits except in growth period, and the coefficient variation of 9 traits is in a decreasing order of effective tiller number per plant 〉 kernel weight per spike 〉 kernel number per spike 〉 spike length 〉 kernel number per spikelet 〉 1 000-grain weight 〉 plant height 〉 spikelet number per spike 〉 growth period. There is different relevance among different traits. Growth period is extremely significantly positively related to yield traits; grain number traits are extremely significantly positively relative to plant height and spike length, but ex- tremely significantly negatively relative to effective tiller number per plant; kernel number per spike is extremely significantly positively relative to kernel weight per spike, but extremely significantly negatively related to 1 000-grain weight; 1 000-grain weight is extremely significantly positively related to kernel weight per spike. Based on principal component analysis, these 9 traits could be included by 5 principal com- ponents （grain number, grain weight, spike length, tiller number and growth period）. According to the comprehensive evaluation values of these five principal components, 50 landraces including ZM019573, ZM019849, ZM019730, ZM018745, ZM019657, ZM019891, ZM020533, ZM018508, 7M019074 and ZM020026 have good performance.

九蒸九制槐角炮制过程主要成分、物性参数及颜色的相关性分析

目的研究九蒸九制槐角炮制过程中主要成分含量、物性参数、颜色的相关性。方法采用高效液相色谱法(HPLC)同时测定槐角苷、染料木苷、芦丁和5-羟甲基糠醛的含量,紫外分光光度法测定多糖的含量;通过测定物性参数和颜色指标(L*、a*、b*),结合系统聚类分析(HCA)、主成分分析(PCA)和偏最小二乘法(PLS)研究主要成分、物性参数及颜色的相关性;采用基于指标相关性的指标权重确定(CRITIC)法对槐角九蒸九制过程的影响进行综合评价。结果含量测定及色度测量方法准确可靠,精密度、稳定性、重复性试验均良好。HCA和PCA结果均表明,槐角饮片炮制过程中一蒸一制至四蒸四制聚为一类,五蒸五制至九蒸九制聚为一类。PLS相关性分析表明,多糖、芦丁的含量与物性参数、颜色均呈显著性相关;吸水膨胀度、相对密度与颜色均呈显著性相关。综合评价显示九蒸九制槐角炮制品最佳。结论九蒸九制槐角炮制过程中主要成分含量、物性参数、颜色的总体变化具有一定规律性,将其内在成分含量与颜色、物性参数结合为揭示槐角九蒸九制炮制机理提供了依据。

改扩建高速公路桥梁可用性评判与延寿准则

针对高速公路改扩建工程中既有桥梁是否能继续使用问题,综合考虑总体技术状况、承载力状况、剩余耐久年限状况3个层次,创建了以桥梁构件类别的外观耐久状态为一级指标、以剩余耐久年限为二级指标的评判方法,提出了表征构件剩余耐久年限的寿命系数和可用寿命系数,建立了既有桥梁的延寿准则和延寿策略,探讨了可用寿命系数与目标使用年限、单次延寿的有效保护年限、拟采取的维护措施类型数量的相互关系。以京沪高速改扩建工程为研究背景,选取9座既有桥梁为典型桥梁,按100 a目标使用年限,计算得到构件主筋和箍筋的剩余耐久年限,给出了典型桥梁主体构件剩余耐久年限。根据可用评判方法,计算得到了在相同延寿措施下的延寿年限、延寿费用及可用寿命系数,按经济最优原则提出了从A级到E级共计5种延寿方式。研究表明,京沪高速改扩建工程典型桥梁按箍筋计算得到构件耐久寿命比按主筋计算值低,建议构件年限按箍筋计算值取用;目标使用年限为100 a时,主梁构件可正常使用比例为94%,墩柱单元、盖梁单元、桥台单元的可正常使用比例分别为67%,11%,44%。实际工程表明,采用该评判方法的评判结果与结构实际状态基本相符,与工程实际采取的处置措施基本相当,验证了该方法的合理性。

德州市制造业企业物流成本核算分析下的主辅分离实践研究

物流被视为企业第三利润源,从制造业企业微观视角出发构建物流成本核算分析体系,有助于企业精准控制物流成本,推进主辅分离实现降本增效。文章通过对德州市制造业企业基于物流成本核算分析下的主辅分离工作进行实证研究,总结介绍了制造业企业构建物流核算体系,利用物流成本数据进行成本结构分析,开展企业物流运作管理优化的典型经验,以期为推动制造业企业实施主辅分离,提高区域产业链供应链水平,实现区域物流业与制造业深入融合发展,优化区域经济产业结构提供参考和借鉴。

江汉平原稻田主要害虫与天敌关系分析

【目的】本研究旨在调查分析江汉平原稻田节肢动物群落的物种组成以及主要害虫与天敌相互作用的关系,为制定水稻害虫绿色防控技术体系提供科学依据。【方法】2019-2020年通过吸虫器法和扫网法在水稻的分蘖期、孕穗期、齐穗期调查江汉平原监利市、潜江市、江陵县等市(县)28块稻田节肢动物物种种类与个体数量,采用主成分分析和灰色关联度分析法分析了各主成分对稻田节肢动物群落的影响以及主要害虫与天敌种群数量之间的关系。【结果】2019-2020年调查的江汉平原稻田节肢动物种类共169种,按照营养取食关系,将稻田节肢动物群落划分为4个亚群落,其中植食类6目33科57种,捕食类7目30科50种,寄生类2目15科44种,中性类5目16科18种。稻田节肢动物群落中对第1主成分贡献大的是白背飞虱Sogatella furcifera和黑尾叶蝉Nephotettix bipunctatus;对第2主成分贡献大的是淡翅小花蝽Orius tantillus和青翅蚁形隐翅虫Paederus fuscipes;对第3主成分贡献大的是稻纵卷叶螟Cnaphalocrocis medinalis和灰飞虱Laodelphax striatellus。与主要害虫稻纵卷叶螟种群数量关联度大的前3位天敌依次为:草间钻头蛛Hylyphantes graminicola>拟环纹豹蛛Pardosa pseudoannulata>三突花蛛Misumenops tricuspidatus。与主要害虫白背飞虱种群数量关联度大的前3位天敌依次为:华丽肖蛸Tetragnatha nitens>黑肩绿盲蝽Cyrtorhinus lividipennis>拟环纹豹蛛。【结论】稻田节肢动物群落构成差异主要是由优势植食性昆虫和优势捕食性天敌数量决定的。捕食动物草间钻头蛛种群数量与稻纵卷叶螟种群数量追随关系最为密切,对稻纵卷叶螟具有一定控制作用,华丽肖蛸的种群数量与白背飞虱种群数量追随关系最为密切,对白背飞虱具有一定控制作用。

影响湖南省空气质量指数的主要气象因子分析

为了落实《湖南省大气污染防治攻坚行动工作方案》对空气质量预报精细化的要求,本研究基于湖南省主要城市2015—2022年间的空气质量数据和气象要素数据,采用统计分析、相关分析、主成分分析法(PCA)等方法,分析了湖南省空气质量指数(AQI)与气象条件之间的关系,提取了影响湖南省不同等级AQI的主要气象因子,并分析了不同等级污染天气的主要气象影响因子。结果显示:(1)在研究期内,湖南空气质量优良天数优于全国平均水平,污染天数分布存在显著的区域差异,部分城市没有出现过严重污染天气。(2)多个气象要素组合构成的气象因子共同对AQI产生影响,影响湖南省AQI的主要气象因子包括气温、水汽与日照组合、平均风速以及降水量;除严重污染天气外,气温因子是影响湖南AQI的首要因子。(3)单个气象要素与AQI之间的相关性较弱。(4)地形的影响使气象条件分布更复杂,而且主要影响AQI的气象因子存在区域差异,增加了AQI精细化预报的难度。

rt-PA静脉溶栓对AIS患者机械取栓后血栓面积及病理成分的影响

目的探讨重组组织型纤溶酶原激活剂(rt-PA)静脉溶栓对急性缺血性脑卒中(AIS)患者机械取栓后血栓面积及病理成分的影响。方法选取2022年1-12月该院卒中中心进行机械取栓手术的120例AIS患者作为研究对象,根据治疗方式分为桥接治疗组(62例)和单纯机械取栓组(58例),桥接治疗组接受rt-PA静脉溶栓+机械取栓治疗,单纯机械取栓组仅接受机械取栓治疗。收集两组患者的一般资料,比较两组美国国立卫生研究院卒中量表(NIHSS)评分及改良Rankin量表(mRS)评分,并对所有机械取栓收集的血栓标本进行处理,分析两组患者血栓特征。结果两组基线资料比较,差异均无统计学意义(P>0.05)。两组治疗前NIHSS与mRS评分比较,差异均无统计学意义(P>0.05);治疗后,两组NIHSS、mRS评分均较治疗前降低,差异均有统计学意义(P<0.05),但两组间比较,差异均无统计学意义(P>0.05)。两组术后血管成功再通率及90 d预后良好率比较,差异均无统计学意义(P>0.05)。两组血栓中的红细胞占比、纤维蛋白/血小板占比、白细胞占比比较,差异均无统计学意义(P>0.05),但桥接治疗组的血栓总面积、红细胞面积、纤维蛋白/血小板面积、白细胞面积明显小于单纯机械取栓组,差异均有统计学意义(P<0.05)。结论rt-PA静脉溶栓可明显减少AIS患者机械取栓后的血栓面积,同时对血栓主要病理成分的面积也有缩减作用,但对血栓主要病理成分的占比不构成影响。

多元热流体开发效果模拟及影响因素关联分析

多元热流体在稠油开发中得到了广泛的应用,但是由于其增油机理较为复杂,因此对其注入参数进行合理设计较为困难。利用数值模拟技术分析了多元热流体开发与蒸汽吞吐的作用效果差异,印证多元热流体增油机理的同时,研究了不同注入温度、注入速率以及焖井时间条件下多元热流体对开发效果的影响。结果表明,这些注入参数存在一个最佳的数值范围。进一步结合现场多元热流体应用井的实际生产数据对其开发效果的主控因素进行分析,得到注入强度、注入速度和注入温度是影响多元热流体开发效果的主要因素。研究结果为多元热流体开发工艺参数设计提供了指导。

陕西省葡萄主产区土壤养分状况分析初报

为探明陕西省葡萄主产区果园土壤养分状况,以主产区渭南、西安、咸阳和宝鸡的葡萄园土壤为研究对象,分别测定0~20、20~40、40~60 cm土层土壤理化性质和营养成分。结果表明:陕西省葡萄主产区内,总体上土壤pH值为强碱性,土壤容重大,土壤过于紧实,有机质含量偏低;氮含量偏低,而磷、钾含量较高,且含量在土壤垂直水平上分布不均匀,除速效氮含量随着土层深度的增加而增加外,全氮、全磷、全钾、速效磷、速效钾含量均随着土层深度的增加而降低;Cu含量丰富,Fe、Mn含量缺乏,Zn含量除在0~20 cm土层丰富外,在更深的两个土层含量急剧下降,处于一种缺乏的状态,Fe、Mn、Zn、Cu含量均随着土层深度的增加而降低。

基于超微消解结合电感耦合等离子体质谱法的核桃产地溯源

目的探究6种产地来源核桃中20种矿物质元素与种植区域的相关性,实现产地溯源。方法样品经超微消解仪处理后,利用电感耦合等离子体质谱仪测定20种矿物质元素含量,对数据进行主成分分析,筛选出特征元素,并对特征元素与种植区域的相关性进行系统聚类分析。结果核桃样品中20种矿物质元素检测方法的线性关系良好,相关系数大于0.99,检出限为0~24.23μg/L,该方法的精密度、稳定性的相对标准偏差均小于7.4%,样品加标回收率为80.4%~119.3%、相对标准偏差为2.1%~7.9%(n=3)。6种产地来源核桃样品中,常量元素由高到低是K、Mg、Ca,大部分样品微量元素含量由高到低为Mn、Fe、Zn、Cu。主成分分析确定Na、Sr、Mn、Cu、Rb、Ni、Zn、Al和Cs 9种元素为甘肃徽县、陕西商南县、四川盐边县、云南漾濞县、新疆喀什及阿克苏地区共36批核桃中矿物质元素的特征成分。结论主成分分析和特征元素分析发现不同产区核桃元素含量的差异较大,本研究可以应用在核桃产地鉴定中,为核桃的产地溯源体系建设提供参考和技术支持。

基于X射线数字成像的GIS设备缺陷无损检测方法

GIS设备的安全性和可靠性对电力体系的平稳运行具有重要意义;因此,为提高对GIS设备缺陷的检测效果、提高设备运行的安全性,在X射线数字成像的基础上,提出一种针对GIS设备的缺陷无损检测方法;通过X射线数字成像的方式采集GIS设备图像,并对图像中存在的泊松噪声实施去噪处理,以提高图像质量;针对处理后的图像,利用二维主成分分析法,通过将复杂的图像数据转换为简单的主成分来表示原始数据,提取出最具代表性的特征;将提取结果输入到BP神经网络分类器中,通过特征分类完成对GIS设备缺陷的无损检测;实验结果表明:应用该方法后,图像识别清晰度较高,对不同类型缺陷的检测效果良好;该方法的优势在于使用先进的图像处理和机器学习技术,能够有效地识别和定位GIS设备中存在的缺陷,通过及时发现并修复这些缺陷,可以提高GIS设备的安全性和可靠性,从而确保电力系统的平稳运行。

基于多特征参数融合降维的主轴承故障识别方法

针对航空发动机主轴承故障信号传输路径复杂、不稳定和故障特征提取困难的特点,提出了一种基于时域特征参数、频域特征参数和本征模态函数(intrinsic mode function,IMF)能量矩特征参数融合降维的故障识别方法。首先,分别选取60组轴承滚动体故障、内圈故障、外圈故障和正常轴承数据,提取时域特征、频域特征及能量矩特征。由于3种参数组成的融合向量维度过大、数据量庞大和信息冗余,利用主成分分析方法(principal component analysis,PCA)对3种数据进行融合降维,根据主成分累积贡献率提取有效的主成分分量。最后,将降维后的特征向量输入支持向量机(support vector machine,SVM)中进行模式识别,诊断不同类型的轴承故障。结果表明,相对于使用单一特征参数等模型的故障识别正确率,该方法能够在复杂的信号中提取出有效的故障特征向量,之后运用故障特征向量准确地对故障类型进行识别分类,故障识别率达到98.75%。

盐酸甲氧氯普胺注射液中有关物质检测方法研究

目的:建立高效液相色谱-加校正因子的主成分自身对照法测定盐酸甲氧氯普胺注射液中的有关物质,为该产品的质量控制和评价提供数据支持。方法:采用赛分Sepax Amethyst C_(18)-H色谱柱(4.6 mm×250 mm,5μm),流动相A为0.02 mol·L^(-1)磷酸溶液(加三乙胺调pH至3.8),流动相B为乙腈,梯度洗脱,流速1.0 mL·min^(-1),柱温35℃,检测波长275 nm,进样量为20μL。结果:主成分峰与各杂质色谱峰分离良好,甲氧氯普胺及各杂质在各自质量浓度范围内与峰面积呈良好线性关系(r=1.0000,n=6),检测限在0.03~0.05μg·mL^(-1),定量限在0.10~0.16μg·mL^(-1),杂质1~5的校正因子分别0.71、0.79、1.10、0.96和0.67;平均回收率为98.7%~100.6%(n=9),重复性、精密度和稳定性均符合相关要求。2家企业6批次的盐酸甲氧氯普胺注射液采用加校正因子的主成分自身对照法测定的结果与对照品外标法基本一致。与国内外药典方法比较,本方法对单杂质、总杂质和特定杂质均进行了控制,且分离效能、检出的杂质个数和杂质量均高于其他药典方法。结论:建立的高效液相色谱-加校正因子的主成分自身对照法可用于盐酸甲氧氯普胺注射液的有关物质测定,为其有关物质质量控制方法的改进提供了数据支持。

电子鼻结合HS-SPME-GC-MS技术解析贵州主产区红酸汤香气成分

利用电子鼻结合顶空固相微萃取-气质联用(HS-SPME-GC-MS)技术检测红酸汤样品的挥发性风味成分,通过测色仪测定红酸汤的颜色参数,采用正交偏最小二乘法判别分析(OPLS-DA)构建模型,研究贵州主产区红酸汤的香气成分构成及差异。基于气味活度值(OAV)和变量投影重要性(VIP)值筛选关键风味物质(OAV>1)和关键差异风味物质(OAV>1且VIP>1)。结果表明,4种红酸汤样品的L^(*)值、a^(*)值、b^(*)值存在显著差异(P<0.05)。电子鼻分析结果表明,4种红酸汤样品具有相似的风味轮廓,但其挥发性风味物质有所差异,对硫化物、芳香类化合物电子鼻响应值最高,基于电子鼻响应值的主成分分析(PCA)及线性判别分析(LDA)能够有效区分不同产区红酸汤样品。通过HS-SPME-GC-MS从4种红酸汤样品中共检测出132种挥发性风味物质,其中3个及以上红酸汤样品共有的香气物质26种。红酸汤样品中筛选出9种关键风味物质和2种关键差异风味物质。

基于KPCA-IPOA-BiGRU的联合循环余热锅炉主蒸汽参数预测

余热锅炉主蒸汽参数对于联合循环机组的健康运行判断至关重要。针对余热锅炉运行参数非线性和时延性导致主蒸汽参数预测精度低的问题,提出了一种联合循环余热锅炉主蒸汽参数预测模型。首先,采集燃机电厂的SIS运行数据,通过灰色相关性分析法确定输入变量;其次,通过核主成分分析(kernel principal component analysis,KPCA)提取输入参数的特征信息,并根据主成分贡献率选取输入维度;最后,利用改进的鹈鹕优化算法(improved pelican optimization algorithm,IPOA)优化双向门控循环神经网络(bi-directional gated recirculation neural network,BiGRU),并构建KPCA-IPOA-BiGRU进行三压余热锅炉主蒸汽参数的预测测验。结果表明,现场采集的10000组数据点,其中8000组用作训练集,2000组用作测试集,提出的模型将28维输入参数降低至8维,可准确预测3个压力级的蒸汽参数,且R2均大于98%,为预测时延性的联合循环余热锅炉主蒸汽参数提供了技术支持。

鱼胶的种类、成分及功效研究进展

鱼胶是一种食药两用的滋补佳品,因突出的补充胶原蛋白、美容养颜、调节内分泌、提高免疫力等功效而备受消费者青睐。然而,目前国内外对鱼胶的研究较少且缺乏对消费者所关注问题的研究。为促进我国鱼胶产业持续发展,本文对市面上流行鱼胶的种类及特征,鱼胶的主要成分及功效,鱼胶产业发展所面临的问题进行系统综述,提出应加强对鱼胶的鉴别分类、功效、质量标准的研究,以期为鱼胶科学食用及产品开发提供参考。