轨道车辆垂向轮轨力时域识别对比及其机器学习修正

为了尽可能减小轨道车辆垂向轮轨力时域识别中存在的误差,以时域法为基础,开展了基于机器学习修正的轨道车辆垂向轮轨力识别研究.首先建立了车辆动力学仿真模型,获取了车辆在随机轨道激励下以250km/h速度行驶时的轴箱加速度响应和垂向轮轨力.其次,建立了Green函数法、状态空间法这2种时域法对应的动载荷识别模型,对状态空间法的初值误差进行了分析,并引入多项式拟合法修正其趋势项误差,进而对比分析了2种方法的计算精度和计算效率.然后,针对时域法存在的识别误差,提出采用NARX(nonlinear autoregressive models with exogenous inputs)模型对识别误差进行训练和预测,用于消减模型中存在的如响应观测不全与观测噪声等因素造成的影响,进而对时域法识别结果进行修正,提高识别精度.最后,通过一个10自由度轨道车辆垂向动力学模型,对方法的正确性进行了验证.研究结果表明:2种方法对轨道车辆垂向轮轨力均具有较高的识别精度,对于各轮对的识别精度各有优劣;在计算效率方面,状态空间法比Green函数法更优;经NARX模型修正的2种时域法对轨道车辆垂向轮轨力均具有很好的识别效果,识别值与正演值的Pearson相关系数大于0.99,为极强相关.基于NARX模型的机器学习误差修正方法可有效提高时域识别精度,可以为后续轨道车辆轮轨力预测提供参考,具有较强的工程运用价值.

水禽细小病毒SYBR Green Ⅰ荧光定量PCR检测方法的建立与应用

为了建立水禽细小病毒(WPV)快速检测方法,根据序列比对结果在水禽细小病毒NS基因SF3保守区域内设计特异性引物,建立SYBR Green Ⅰ荧光定量PCR通用检测方法。该方法的扩增效率(E)为90.0%,相关系数(R~2)=0.99,标准曲线方程为y=-3.607x+38.77;除WPV出现S形扩增曲线外,新城疫病毒(NDV)、H9亚型禽流感病毒(H9 AIV)、鸭坦布苏病毒(DTMUV)、鸭肝炎病毒(DHAV)、鸭肠炎病毒(DEV)、鸭呼肠孤病毒(DRV)样品均未出现S形阳性扩增曲线;批内变异系数(CV)为0.15%~0.23%,批间变异系数为0.09%~0.28%。结果表明,SYBR Green Ⅰ荧光定量PCR检测方法重复性好、灵敏度高和特异性强。临床样品检测结果表明,SYBR Green Ⅰ荧光定量PCR与普通PCR的符合率达98.4%,灵敏度是普通PCR的1 000倍。SYBR Green Ⅰ荧光定量PCR检测方法不仅能定性检测WPV,还可以进行定量检测,可用于种鸭场、种鹅场的WPV净化检测,也可用于WPV临床大量样品的快速检测。

盆底超声检查和Green分型诊断产妇产后早期盆底结构及压力性尿失禁

目的:探究盆底超声检查和Green分型在产妇产后早期盆底结构及压力性尿失禁(SUI)诊断中的价值。方法:选取2021年3月-2023年3月本院就诊经产妇204例,根据产后早期(6~8周)SUI发生情况分为SUI组(82例)和非SUI组(122例)。检查产妇静息和Valsalva动作状态下膀胱颈距耻骨联合下缘的距离(BSD)、膀胱尿道后角(PUA)、膀胱颈移动度(BND)和尿道旋转角(UR),对比Green分型;采用受试者工作特征(ROC)曲线分析相关参数诊断SUI价值。结果:静息状态下,两组盆底超声参数无差异(P>0.05);SUI组Valsalva动作状态下的BSD、PUA、BND和UR值均大于非SUI组,Green分型Ι型占比(25.6%)低于非SUI组(59.8%)(均P<0.05)。ROC曲线分析,Green分型曲线下面积(AUC)0.579,对SUI诊断价值不佳(P=0.057),Valsalva动作状态下BSD(AUC=0.758)、PUA(AUC=0.743)、BND(AUC=0.769)和UR(AUC=0.705)对SUI诊断价值良好(均P<0.05)。结论:盆底超声检查和Green分型能有效评估经产妇早期盆底结构状况,前者可诊断SUI。

约束Green函数与非线性地基梁模态分析

在生物和医学领域,微机电系统(MEMS)中的微梁结构在植入人体的使用时,由于体内的细胞环境类似于水凝胶,在这种环境下工作,设备和仪器的精度和稳定性很大程度上受到细胞弹性的影响.为了分析此类地基梁的动力学问题,本文建立了非线性基础上的梁振动模型,研究了任意位置弹簧和非线性弹簧基础上的梁模态.通过Laplace变换和线性叠加原理,得到了一种约束Green函数,利用数值计算验证方案的有效性,并研究了各种重要物理参数的影响,发现弹簧位置向跨中移动时,模态对称性被打破,弹簧刚度增加,模态阶数改变.

猪流行性腹泻病毒SYBR Green I实时荧光定量PCR检测方法的建立

为了建立高效、灵敏的猪流行性腹泻病毒(PEDV)检测方法,本研究从GenBank数据库中获取PEDV N基因序列,扩增出PEDV N基因标准质粒,并在N基因的保守区域内设计了一对特异性荧光定量引物,成功建立了SYBR Green I实时荧光定量PCR检测方法。经过一系列试验表明,该检测方法线性关系良好,R^(2)值为0.99;特异性强,敏感性高,最低可检测至2.23 copies/μL,比普通PCR灵敏约100倍;重复性好,组内变异系数为0.25%~0.43%,组间变异系数为0.67%~0.97%;对于各地区96份临床样品检测出PEDV阳性率为25%。本研究建立的实时荧光定量PCR检测方法为PEDV的临床诊断、流行病学调查以及定量研究提供了有效的检测工具。

美洲鳗鲡腺瘤病毒(AEAdoV)普通PCR和SYBR Green I实时荧光定量PCR检测方法的建立及应用

为建立美洲鳗鲡腺瘤病毒(AEAdoV)的检测方法,根据AEAdoV福建株(AEAdoVFJ)的superfamily 3 helicases(S3H)序列,设计引物,建立了AEAdoV的普通PCR和qPCR检测方法;进一步评价检测方法的灵敏性、特异性及重复性,利用2种方法对美洲鳗鲡“出血性烂鳃”病料进行了检测,并对美洲鳗鲡体内不同组织的病毒含量进行分析。结果显示,普通PCR扩增的目的片段长度约300 bp,利用其构建的qPCR质粒标准品,其拷贝数与qPCR阈值循环数(C_(t))线性关系良好,线性范围广,标准曲线相关系数(R2)达到0.999,扩增效率为105.067%。建立的普通PCR法和qPCR的最低检测AEAdoV拷贝数分别为100个和10个。2种方法均可特异性检测AEAdoV,而对蛙虹彩病毒(RGV)、鳗鲡疱疹病毒(AngHV)、鲤疱疹病毒(KHV)、对虾白斑综合征病毒(WSSV)、日本鳗鲡内皮细胞坏死病毒(JEAdoV)和花鳗鲡腺瘤病毒(MEAdoV)均无扩增反应。qPCR法的组内和组间变异系数均小于2%,表明其重复性良好。临床应用结果显示,35份美洲鳗鲡“出血性烂鳃”病料,采用普通PCR法的AEAdoV检出率为82.8%,而qPCR法的AEAdoV检出率为97%。对美洲鳗鲡不同组织的病毒含量分析结果显示,心脏、肝脏、鳃、鳍的AEAdoV相对含量较高,而黏液、皮肤和脾脏的病毒含量相对较低。研究表明,建立的AEAdoV的灵敏度高、特异性强的普通PCR和qPCR检测方法,证实AEAdoV与美洲鳗鲡“出血性烂鳃”病密切相关,且在感染鳗鲡主要组织中都存在。实验结果对于研究AEAdoV的致病性,开展其流行情况和病原学情况分析具有重要意义。

水貂圆环病毒实时荧光定量PCR检测方法的建立与应用

为快速检测水貂圆环病毒(MiCV),本试验根据MiCV Cap基因序列设计合成特异性引物,建立了水貂圆环病毒SYBR Green II实时荧光定量PCR检测方法。结果显示,该方法在模板浓度为1.0×10^(6)~1.0×10^(1) copies/μL范围内呈良好线性关系,相关系数为0.9983。本试验建立的检测方法对水貂阿留申病毒、猪圆环病毒2型、水貂肠炎病毒、犬瘟热病毒和猪伪狂犬病毒进行检测均无特异性扩增,批内和批间CV均小于2%,对重组阳性质粒的检测下限为1.0×10^(1) copies/μL,比普通PCR的敏感度高100倍,对阳性样品DNA的检测下限为2.38×10^(-2) pg/μL,比普通PCR的敏感度高1000倍。应用该方法对吉林省部分毛皮动物养殖场的水貂、狐狸、貉和环境样品进行检测,结果其阳性率分别为57.23%、48.42%、39.71%和68.48%。上述结果表明,本研究建立的实时荧光定量PCR检测方法具有良好的灵敏性、特异性和重复性,为MiCV的诊断及流行病学调查提供技术支持。

香辛料SYBR GREENⅠ染料实时聚合酶链式反应检测方法的建立及应用

目的:本研究致力于建立香辛料真实性成分的分子鉴定方法,为香辛料的掺假提供有效的鉴定和检测方法,在不同的使用条件下分别实现定性或半定量分析,为建立相关标准提供一定的基础技术支撑。方法:研究采用SYBR GREENⅠ染料实时聚合酶链式反应(polymerase chain reaction,PCR)方法,通过设计特异性引物成功建立了特异性检测八角、茴香、胡椒和花椒的分析技术。结果:该方法能够特异性检测出八角、茴香、胡椒、花椒,Ct值在标准品体积分数0.001%~10%范围内线性关系良好。针对八角标准品,检测限为1%;针对茴香、花椒、胡椒标准品,最检测限均为0.001%。利用该方法对5份实际样本进行检测,分别在样本1中未检测出八角、茴香、胡椒、花椒;样本2、3、5中检测出八角、茴香、胡椒;样本4中检测出八角、茴香、胡椒、花椒。结论:本实验建立的SYBR GREENⅠ染料实时PCR方法灵敏度高、重复性好,可应用于实际样品的检测。

小反刍兽疫LAMP反应结果可视化检测方法比较研究

环介导等温扩增(loop-mediated isothermal amplification,LAMP)技术是一种可应用于各种病原体检测、基因分型等领域的等温扩增技术。该技术所需设备简单且易于操作,因此具有较大的发展潜力。根据目前已经存在的判定LAMP结果的可视化方法,以可能对野生小反刍动物造成威胁的小反刍兽疫病毒(Peste des petits ruminants virus,PPRV)cDNA为检测对象,选择合适的引物组,比较评估均可在日光或紫外光下区分阴阳性结果的SYBR Green I、SYBR Safe Stain和羟基萘酚蓝(hydroxy naphthol blue,HNB)3种指示剂方法的适用性与灵敏度。结果表明:3种方法的灵敏度都很高,均与琼脂糖凝胶电泳相当。其中,SYBR Green I结果区分度高、不受体系成分影响且无须额外设备,但成本较高;SYBR Safe Stain具有良好的结果区分度,成本相对较低,但需要额外的紫外照射设备;HNB成本最低,但颜色区分度较低,且易受多种因素影响。建议在选择LAMP指示剂时,综合考虑成本、使用便利性、结果准确性及实验条件,通过充分的体系优化和验证,确保LAMP检测的准确性和可靠性。研究结果突显了不同方法的特征和适用场景,为研究人员根据不同场所与条件选择高效、便捷的LAMP反应结果可视化方法提供参考。

风力机叶片强迫振动的格林函数解

利用Euler-Bernoulli梁模型和Greenberg表达式构建了风力机叶片弯曲-弯曲-扭转耦合强迫振动方程。基于振动方程将位移分解为准静态位移和动态位移,通过Laplace变换和叠加原理得到风力机叶片强迫振动的Fredholm积分方程组,通过对方程组离散,最终求得风力机叶片弯曲-弯曲-扭转耦合强迫振动的Green函数半解析解。通过数值计算,将所得的解与现有文献的解进行比较,验证了解的准确性。研究表明,无量纲阻尼系数的大小只对叶片一阶固有频率峰值影响较大,并且叶片在挥舞振动下的隔振区域出现在二阶固有频率之后,而摆振下的隔振区域出现在一阶和二阶固有频率之间;叶片的入流角和转速对叶片振动响应的影响不容忽视,叶片的耦合振动会导致叶片的准静态位移显著增加。

禽源沙门氏菌荧光定量PCR方法的构建及应用

试验旨在建立一种快速检测禽源沙门氏菌SYBR Green Ⅰ荧光定量PCR(qPCR)的方法,即根据沙门氏菌invA基因的保守序列设计引物,利用普通PCR方法扩增沙门氏菌invA基因保守基因片段,将其克隆到pMD18-T载体上,将获得的重组质粒pMD18-T-invA作为标准阳性模板。经qPCR条件优化后,进行特异性、灵敏性和重复性试验。结果显示,所建立的SYBR Green Ⅰ qPCR方法的Ct值与标准品在1.4~1.4×10^(10)拷贝/μL范围内呈良好的线性关系,R2为0.9963,扩增效率为95%,检测下限为1.4拷贝/μL;与大肠埃希菌、金黄色葡萄球菌、链球菌、痢疾志贺菌、多杀性巴氏杆菌无交叉反应;该方法组内变异系数和组间变异系数均小于2.5%;对44份粪便样本和132份蛋液样本进行qPCR方法和常规PCR方法检测,结果显示该qPCR方法的阳性检出率分别为22.7%(10/44)、0.8%(1/132),常规PCR的阳性检出率分别为9.1%(4/44),0%(0/132)。结果表明:试验成功建立禽源沙门氏菌qPCR检测方法,可为禽源沙门氏菌的快速检测提供技术支撑。

和美乡村视角下的苏南农田“GREEN”水环境治理模式应用研究

随着中国宜居宜业和美乡村建设的不断深入,乡村水环境的治理与保护作为乡村生态文明建设的重要组成部分日益受到社会的重视和关注。在以往大规模灰色基础设施建设的背景下,乡村忽略了对于水生态绿色基础设施的构建,生态格局趋于破碎。农田空间作为农业面源污染的重要源头,结合多学科视角探索农田水环境污染治理新模式具有高度的必要性。立足于苏南地区独特的农田水网体系,紧密结合农业空间生产属性,研究现有农田水环境治理理论方法与实际建设,提炼以“源头绿色—过程净化—末端吸收—生态保育—循环回用”的苏南农田“GREEN”水环境治理模式,探索风景园林学科水治理方法在农田沟渠、河道及湿地等乡村空间的运用路径,并以常州市中天黄金大农场总体规划为例进行实践应用。推动风景园林学科于乡村生产空间的应用模式探索,为未来农业面源污染防治提供参考借鉴。

Does Green Food Certification promote agri-food export quality?Evidence from China

The construction of a food certification system plays a vital role in upgrading export quality, which previous studies have largely overlooked. We match China's industry-level data of Green Food Certification with its HS6-digit export data of agri-food products to quantify the impact of Green Food Certification on export quality. We identify the significant and positive effect of Green Food Certification on export quality. The 2SLS estimation based on instrumental variables and a range of robustness checks confirm the validity and robustness of the benchmark conclusions. Further analysis discloses that Green Food Certification improves export quality by raising agricultural production efficiency and brand premiums. Heterogeneity analysis shows that the effect of Green Food Certification varies across regions, notably improving the quality of agri-food products exported to developed regions and regions with high levels of import supervision. Furthermore, among various product types, Green Food Certification significantly improves the export quality of primary products and products vulnerable to non-tariff measures. The above findings could guide the future development of agri-food quality certification systems, potentially leading to a transformation and promotion of the agri-food trade.

Green Synthesis of Iron(Ⅱ,Ⅲ)-polyphenol Nanoparticles and Their Adsorption of Malachite Green

Three kinds of iron nanoparticles(FeNPs)were prepared via green route based on pomegranate(PG),green tea(GT),and mulberry(ML)extracts under ambient conditions.The obtained materials were characterized by scanning electron microscopy(SEM),transmission electronic microscopy(TEM),X-ray energy-dispersive spectrometer(EDS),X-ray diffraction(XRD),fourier transform infrared spectroscopy(FTIR),and X-ray photoelectron spectroscopy(XPS)techniques.The experimental results show that FeNPs were in the form of amorphous iron(Ⅱ,Ⅲ)-polyphenol complex with different dispersity and morphologies.GT-Fe has the smallest size range of 25-35 nm,PG-Fe has a moderate size-distribution of 30-40 nm,while ML-Fe formed a tuberous net-type with a sheeting structure.PG-Fe displays the highest removal efficiency of 90.2%in 20 min towards cationic dye of malachite green(16.6%by ML-Fe and 69.3%by GT-Fe),which is attributed to its highest polyphenol content,lowest zeta potential,as well as the most Fe^(2+)on the surface of FeNPs.The removal mechanism was mainly induced by electrostatic adsorption based on pH and zeta potential tests.

Towards the insights into the deactivation behavior of acetylene hydrogenation catalyst

A series of model catalysts were obtained by treating commercial fresh and spent catalysts unloaded from the factory with different methods, including green oil dipping, extraction and high-temperature regeneration;finally, the deactivation behavior of the commercial catalyst for acetylene hydrogenation were studied. The influence of various possible deactivation factors on the catalytic performance was elucidated via detailed structural characterization, surface composition analysis, and activity evaluation.The results showed that green oil, carbon deposit and sintering of active metal were the main reasons for deactivation, among which green oil and carbon deposit led to rapid deactivation, while the activity could be recovered after regeneration by high-temperature calcination. The sintering of active metal components was attributed to the high-temperature regeneration in hydrothermal conditions, which was slow but irreversible and accounted for permanent deactivation. Thus, optimizing the regeneration is expected to extend the service life of the commercial catalyst.

Deep eutectic solvents:Green multi-task agents for sustainable super green hydrogen technologies

While reliance on renewable energy resources has become a reality, there is still a need to deploy greener and more sustainable methods in order to achieve sustainable development goals. Indeed, green hydrogen is currently believed to be a reliable solution for global warming and the pollution challenges arising from fossil fuels, making it the resilient fuel of the future. However, the sustainability of green hydrogen technologies is yet to be achieved. In this context, generation of green hydrogen with the aid of deep eutectic solvents(DESs) as green mixtures has been demonstrated as a promising research area. This systematic review article covers green hydrogen generation through water splitting and biomass fermentation when DESs are utilized within the generation process. It also discusses the incorporation of DESs in fuel cell technologies. DESs can play a variety of roles such as solvent, electrolyte, or precursor;colloidal suspension and reaction medium;galvanic replacement, shape-controlling, decoration, or extractive agent;finally oxidant. These roles are relevant to several methods of green hydrogen generation, including electrocatalysis, photocatalysis, and fermentation. As such, it is of utmost importance to screen potential DES formulations and determine how they can function in and contribute throughout the green hydrogen mobility stages. The realization of super green hydrogen generation stands out as a pivotal milestone in our journey towards achieving a more sustainable form of development;DESs have great potential in making this milestone achievable. Overall, incorporating DESs in hydrogen generation constitutes a promising research area and offers potential scalability for green hydrogen production, storage,transport, and utilization.

A green cross-linking method for the preparation of renewable threedimensional graphene sponges for efficient adsorption of Congo red dye

Graphene-based materials possess significant potential for the treatment of dye wastewater due to their exceptional adsorption properties toward stubborn pollutants.However,their utilization is hindered by high preparation costs,low yields,environmental pollution during synthesis,and challenges in regenerating the adsorbent.This study proposes a novel approach to address these limitations by developing nitrogen-doped three-dimensional(3D)polyvinyl alcohol(PVA)crosslinked graphene sponges(N-PGA)using a cross-linking method with ammonium carbonate.This method offers a relatively mild,environmentally friendly approach.Ammonium carbonate serves as both a reducing and modifying agent,facilitating the formation of the intrinsic structure of N-PGA and acting as a nitrogen source.Meanwhile,PVA is utilized as the cross-linking agent.The results demonstrate that N-PGA exhibits a favorable internal 3D hierarchical porous structure and possesses robust mechanical properties.The measured specific surface area(BET)of N-PGA was as high as406.538 m^(2)·g^(-1),which was favorable for its efficient adsorption of Congo red(CR)dye molecules.At an initial concentration of 50 mg·L^(-1),N-PGA achieved an impressive removal rate of 89.6%and an adsorption capacity of 112 mg·g^(-1)for CR dye.Furthermore,it retained 79%of its initial adsorption capacity after 10 cycles,demonstrating excellent regeneration performance.In summary,the synthesized N-PGA displays remarkable efficacy in the adsorption of CR dye in wastewater,opening up new possibilities for utilizing 3D porous graphene nanomaterials as efficient adsorbents in wastewater treatment.

Eutrophication of Jiangsu Coastal Water and Its Role in the Formation of Green Tide

Since 2007,the large-scale green tide caused by Ulva prolifera(U.prolifera)have occurred as a recurrent phenomenon in the southern Yellow Sea of China.Field surveys and satellite remote sensing showed that the small scattered patches of green tide algae were first observed along the Porphyra agriculture area of the Subei Shoal in late April.In this study,we attempted to identify the role of eutrophication in the origin of the green tide in the Subei Shoal and its adjacent area.Subei Shoal and its adjacent area are characterized by rich nutrients,especially NO_(3)^(-)-N,NH_(4)^(+)-N,PO_(4)^(3-)-P,and other bioavailable components(such as urea-N and amino acids).In the spring of 2017,the average concentrations of NO_(3)^(-)-N were 19.01±11.01μmolL^(-1),accounting for 86.68%of the dis-solved inorganic nitrogen(DIN).In addition,the average concentration of NH4^(+)-N was 2.51±1.60μmolL^(-1).PO_(4)^(3-)-P had an average concentration of 0.14±0.13μmolL-1.The average concentrations of urea-N and total hydrolyzed amino acids(THAA)were 1.73±1.36μmolL^(-1)and 1.33±0.80μmolL^(-1),respectively.Rich nutritive substances play a key role in the rapid production of U.prolifera and make the Jiangsu coastal water an incubator for green tide.

Making the Complicated Simple:A Minimizing Carrier Strategy on Innovative Nanopesticides

The flourishing progress in nanotechnology offers boundless opportunities for agriculture,particularly in the realm of nanopesticides research and development.However,concerns have been raised regarding the human and environmental safety issues stemming from the unrestrained use of non-therapeutic nanomaterials in nanopesticides.It is also important to consider whether the current development strategy of nanopesticides based on nanocarriers can strike a balance between investment and return,and if the complex material composition genuinely improves the efficiency,safety,and circularity of nanopesticides.Herein,we introduced the concept of nanopesticides with minimizing carriers(NMC)prepared through prodrug design and molecular self-assembly emerging as practical tools to address the current limitations,and compared it with nanopesticides employing non-therapeutic nanomaterials as carriers(NNC).We further summarized the current development strategy of NMC and examined potential challenges in its preparation,performance,and production.Overall,we asserted that the development of NMC systems can serve as the innovative driving force catalyzing a green and efficient revolution in nanopesticides,offering a way out of the current predicament.

Exploring nitrogen reduction reaction mechanisms in electrocatalytic ammonia synthesis:A comprehensive review

The electrochemical nitrogen reduction reaction(eNRR)holds significant promise as a sustainable alternative to the conventional large-scale Haber Bosch process,offering a carbon footprint-free approach for ammonia synthesis.While the process is thermodynamically feasible at ambient temperature and pressure,challenges such as the competing hydrogen evolution reaction,low nitrogen solubility in electrolytes,and the activation of inert dinitrogen(N_(2))gas adversely affect the performance of ammonia production.These hurdles result in low Faradaic efficiency and low ammonia production rate,which pose obstacles to the commercialisation of the process.Researchers have been actively designing and proposing various electrocatalysts to address these issues,but challenges still need to be resolved.A key strategy in electrocatalyst design lies in understanding the underlying mechanisms that govern the success or failure of the electrocatalyst in driving the electrochemical reaction.Through mechanistic studies,we gain valuable insights into the factors affecting the reaction,enabling us to propose optimised designs to overcome the barriers.This review aims to provide a comprehensive understanding of the various mechanisms involved in eNRR on the electrocatalyst surface.It delves into the various mechanisms such as dissociative,associative,Mars-van Krevelen,lithium-mediated nitrogen reduction and surface hydrogenation mechanisms of nitrogen reduction.By unravelling the intricacies of eNRR mechanisms and exploring promising avenues,we can pave the way for more efficient and commercially viable ammonia synthesis through this sustainable electrochemical process by designing an efficient electrocatalyst.