关于PA-250感应电机效率提高的研究

随着社会经济的飞速发展,对于节能环保的要求越来越高,传统的G/M代码已经成为现代先进制造技术的瓶颈。而基于STEP标准的STEP-NC将为现代CNC的高速和高精度加工提供条件。     

对-羟基苯甲酸对东北山樱桃叶绿素荧光参数的影响

以东北山樱桃(Cerasus sachalinensis Kom.)实生幼苗为试材,利用Hansatch PEA,采用叶绿素荧光诱导动力学理论和JIP-test数据分析方法,研究了对-羟基苯甲酸对叶片叶绿素荧光参数的影响。结果表明:幼苗在不同浓度对-羟基苯甲酸(0.1A、1A、10A)处理下的叶片光合性能指数(PIABS)、捕获的激子将电子传递到电子传递链中QA-下游的其他电子受体的概率(Ψo)、用于电子传递的量子产额(φEo)和单位面积有活性的反应中心数目(RC/CSm)较对照均有所下降;PSⅡ最大量子效率(φPo)、单位面积有活性的反应中心数目(RC/CS0)几乎没有变化;而PSⅡ受体侧的电子受体库容量(Sm)则高于对照,且呈"上升-下降"趋势。天线色素吸收的能量(ABS/RC)在低浓度下有小幅升高,反应中心捕获的能量(TRo/RC)、用于电子传递的能量(ETo/RC)及用于热耗散的能量(DIo/RC)则无明显变化。可见,对-羟基苯甲酸对东北山樱桃叶片光合结构的不同部位产生影响,进而降低光合性能,影响光合作用。     

Mapping soil salinity and pH across an estuarine and alluvial plain using electromagnetic and digital elevation model data

Increasing pressures from agriculture and urbanization have resulted in drainage of many floodplains along the eastern Australian coastline, which are underlain by sulphidic sediments, to lower water tables and reduce soil salinity. This leads to oxidation of the sediments with a rapid decline in pH and an increase in salinity. Accurately mapping soil salinity and pH in coastal acid sulphate soil (CASS) landscapes is therefore important. One required map is the extent of highly acidic (i.e. pH < 4.5) areas, so that the application of alkaline amendments (e.g. lime) to neutralize the acid produced can be specifically targeted to the variation in pH. One approach is to use digital soil mapping (DSM) using ancillary information, such as an EM38, digital elevation models (DEM – elevation) and trend surface parameters (east and north). We used an EM38 in the horizontal (EM38h) and vertical (EM38v) modes together with elevation data to develop multiple linear regressions (MLR) for predicting EC_1:5 and pH. For pH, best results were achieved when the EM38 EC_a data were log‐transformed. By comparing MLR models using REML analysis, we found that using all ancillary data was optimal for mapping EC_1:5, whereas the best predictors for pH were north, log‐EM38v and elevation. Using residual maximum likelihood (REML), the final EC_1:5 and pH maps produced were consistent with previously defined soil landscape units, particularly CASS. The DSM approach used is amenable for mapping saline soils and identifying areas requiring the application of lime to manage acidic soil conditions in CASS landscape.     

The Alleviating Effect of Elevated CO2 on Heat Stress Susceptibility of Two Wheat (Triticum aestivum L.) Cultivars

This study analysed the alleviating effect of elevated CO₂ on stress‐induced decreases in photosynthesis and changes in carbohydrate metabolism in two wheat cultivars (Triticum aestivum L.) of different origin. The plants were grown in ambient (400 μl l^?1) and elevated (800 μl l^?1) CO₂ with a day/night temperature of 15/10 °C. At the growth stages of tillering, booting and anthesis, the plants were subjected to heat stress of 40 °C for three continuous days. Photosynthetic parameters, maximum quantum efficiency of photosystem II (PSII) photochemistry (F_v/F_m) and contents of pigments and carbohydrates in leaves were analysed before and during the stress treatments as well as after 1 day of recovery. Heat stress reduced P_N and F_v/F_m in both wheat cultivars, but plants grown in elevated CO₂ maintained higher P_N and F_v/F_m in comparison with plants grown in ambient CO₂. Heat stress reduced leaf chlorophyll contents and increased leaf sucrose contents in both cultivars grown at ambient and elevated CO₂. The content of hexoses in the leaves increased mainly in the tolerant cultivar in response to the combination of elevated CO₂ and heat stress. The results show that heat stress tolerance in wheat is related to cultivar origin, the phenological stage of the plants and can be alleviated by elevated CO₂. This confirms the complex interrelation between environmental factors and genotypic traits that influence crop performance under various climatic stresses.     

三种荒漠植物叶绿素荧光参数日变化特征

利用Photosynq MultiseQ多功能植物测量仪测定塔克拉玛干沙漠腹地3种主要防护林植物头状沙拐枣、多枝柽柳和梭梭的叶绿素荧光参数日变化,探讨其与环境因子的关系,以揭示3种植物对极端环境的适应策略,为沙漠公路防护林的管护提供理论依据。结果表明：1）3种土壤都呈碱性;0~30 cm土层中的电导率（EC）远高于30 cm以下的土层。1 m内梭梭土层中的含水量高于多枝柽柳高于头状沙拐枣。2）3种植物的光合有效辐射（PAR）、叶片温度和线性电子传递（LEF）及植物周围的大气温度日变化均先升后降,且都在14：00达到最高;而大气湿度、实际光化学效率Y_（II）日变化均呈‘V’型。3）PAR基本上与3种植物的LEF、非光化学淬灭系数（NPQ）、调节性能量耗散量子产量Y_（NPQ）、非调节性能量耗散量子产量Y_（NO）呈显著正相关,与实际光化学效率Y_（II）呈显著负相关;3种植物的Y_（II）与Y_（NPQ）、Y_（NO） 均呈极显著负相关。3种植物的LEF、Y_（II）、Y_（NPQ）的日均值差异不显著,但梭梭与多枝柽柳的NPQ和Y_（NO）日均值差异显著。4）在3种植物的叶绿素荧光参数中,梭梭和头状沙拐枣的LEF、NPQ和Y_（II）要高于多枝柽柳;而多枝柽柳的Y_（NO）要显著高于头状沙拐枣和梭梭。因此,高温和高光均对3种植物造成了不同程度的影响,通过主成分分析表明,3种植物的抗逆性强弱顺序分别为梭梭>头状沙拐枣>多枝柽柳。     

基于非洲猪瘟病毒标准物质的荧光PCR检测试剂盒初步评价

为探究非洲猪瘟病毒(African swine fever virus,ASFV)标准物质作为试剂盒评价体系的可行性,比较了市场上5种主流品牌ASFV荧光PCR检测试剂盒的检测性能。使用ASFV P72基因核酸标准物质作为模板,根据5种试剂盒说明书分别进行相应的荧光定量PCR检测,结合扩增曲线、Ct值,分析不同试剂盒的敏感性、可重复性以及所需反应时间。结果显示:5种试剂盒的阴性、阳性对照均成立,最低检测限均为5.9×10^-1拷贝/μL;4个厂家的试剂盒线性关系R2>0.98,其中最优的R²=0.994,离散度最小;各试剂盒的实际反应耗时与理论反应耗时均有一定差异(0.20~0.96 h)。结果表明,各生产厂家使用P72基因作为靶基因研制的ASFV荧光PCR检测试剂盒都可以使用ASFV标准物质作为评价体系,来评判试剂盒的检测性能。本试验为各实验室不同样品检测的ASFV荧光PCR检测试剂盒选择提供了一种可用的评价方法。     

返青期休牧对退化高寒草地植被特征及优势种光合生理的影响

为探讨返青期休牧对退化高寒草地植被特征及优势种光合生理的影响,本研究在祁连山区选择已实施返青期休牧6年的高寒草甸开展了植被特征及优势种光合生理相关指标的调查研究。结果表明：返青期休牧6年后,高寒草甸的植被盖度、地上生物量、地下生物量和土壤含水量较未休牧区分别增加了38.44%,985.00%,209.56%和62.62%,其优势禾草垂穗披碱草（Elymus nutans）株高、叶片净光合速率、光化学量子效率、呼吸速率、叶面积、相对叶绿素含量和叶片氮含量分别提高了965.77%,139.86%,4.92%,269.37%,254.13%,197.02%和96.24%（P<0.05）,其地上地下生物量与除叶温和光化学猝灭系数外的指标显著相关,叶片净光合速率与除叶温外的指标显著相关。因此,返青期休牧可显著增强高寒草地优势禾草的光合作用和呼吸作用,促进植物生长及退化草地的恢复。本研究为推广实施返青期休牧这一措施来恢复退化高寒草地植被提供了理论基础。     

Dose requirement and cardiopulmonary effects of diluted and undiluted propofol for induction of anaesthesia in dogs

ObjectiveTo compare the dose, cardiopulmonary effects and quality of anaesthetic induction in dogs using propofol (10 mg mL^–1) and diluted propofol (5 mg mL^–1).Study designRandomized, blinded, clinical study.AnimalsA total of 28 client-owned dogs (12 males/16 females).MethodsFollowing intramuscular acepromazine (0.02 mg kg^–1) and methadone (0.2 mg kg^–1), propofol (UP, 10 mg mL^–1) or diluted propofol (DP, 5 mg mL^–1) was administered intravenously (0.2 mL kg^–1 minute^–1) by an anaesthetist unaware of the allocated group to achieve tracheal intubation. Sedation, intubation and induction quality were scored from 0 to 3. Pre- and post-induction pulse rate (PR), respiratory rate (f_R) and systolic (SAP), mean (MAP) and diastolic (DAP) arterial blood pressure were compared. Time to first breath and induction dose were recorded. Data were analysed for normality and Mann–Whitney U or Student t tests were performed where appropriate. Significance was set at p < 0.05. Data are presented as mean ± standard deviation or median (range).ResultsThe propofol dose administered to achieve induction was lower in the DP group (2.62 ± 0.48 mg kg^–1) than in the UP group (3.48 ± 1.17 mg kg^–1) (p = 0.021). No difference was observed in pre- and post-induction PR, SAP, MAP, DAP and f_R between groups. The differences between post-induction and pre-induction values of these variables were also similar between groups. Time to first breath did not differ between groups. Sedation scores were similar between groups. Quality of tracheal intubation was marginally better with UP 0 (0–1) than with DP 1 (0–2) (p = 0.036), but overall quality of induction was similar between groups [UP 0 (0–1) and DP 0 (0–1), p = 0.549].Conclusion and clinical relevanceDiluting propofol reduced the dose to induce anaesthesia without significantly altering the cardiopulmonary variables.     

猪圆环病毒2型灭活疫苗中病毒抗原含量实时荧光定量PCR检测方法的建立

依据GenBank公布的猪圆环病毒2型Cap基因序列,在保守区域设计特异性引物和TaqMan探针,优化反应体系,建立评价猪圆环病毒2型灭活疫苗中病毒含量的实时荧光定量PCR检测方法,对方法的特异性、敏感性和重复性进行试验,并验证灭活剂用量和灭活时间对检测结果的影响。结果显示：该方法只对猪圆环病毒2型基因有特异性扩增,其他3种对照病毒基因的扩增结果均为阴性;检测灵敏度达到10^2.0 TCID₅₀/mL,比普通PCR方法高100倍;方法的重复性好,对同一样品进行10次检测,变异系数为2.28%;不同灭活剂用量和灭活时间对结果的影响较小,不会因各厂家使用的灭活剂用量和灭活时间不同,影响疫苗对比实验的公平性。该研究成功建立了一种评价猪圆环病毒2型灭活疫苗中病毒含量的实时荧光定量PCR检测方法,用于猪圆环病毒2型灭活疫苗样品中病毒抗原含量的定量,其结果可以反映不同猪圆环病毒2型灭活疫苗样品中抗原含量差异,为研究猪圆环病毒2型灭活疫苗病毒抗原含量评估方法提供了新的思路。     

薄壳山核桃疮痂病菌TaqMan荧光定量PCR检测方法的建立及应用

疮痂病是薄壳山核桃上最具毁灭性的病害,带菌植物材料是传播疮痂病的重要来源。准确、灵敏、快速的检测方法可为该病害流行规律调查和防控提供有力的依据。本文通过比较薄壳山核桃疮痂病菌Venturia effusa及其近似种之间的ITS序列差异,设计了特异性引物和TaqMan探针,建立了薄壳山核桃疮痂病菌的荧光定量PCR检测方法。特异性检测结果表明,该方法可以检测不同地区的薄壳山核桃疮痂病菌菌株,而对其近似种以及薄壳山核桃上的其他真菌均没有信号。本研究建立的检测方法对薄壳山核桃疮痂病菌DNA的最低检测限可达0.5 pg/μL。该方法用于田间样品检测时,检测时间仅需1 h,远快于常规的分离培养法。本研究建立的基于TaqMan探针的荧光定量PCR检测方法为薄壳山核桃疮痂病菌的快速检测和监测提供了有力工具。