Molecular weight determination of a newly synthesized guanidinylated disulfide-containing poly(amido amine) by gel permeation chromatography

A cationic gene delivery vector, guanidinylated disulfide-containing poly(amido amine)(CARCBA), was synthesized by Michael addition reaction between N,N′-cystaminebisacrylamide(CBA) and guanidine hydrochloride(CAR). Gel permeation chromatography(GPC) was used to evaluate the molecular weight of synthesized CAR-CBA. Polyethyleneimine(PEI) with molecular weight of 25 kDa was adopted as a reference, and polyethylene glycols(PEG) with different molecular weights were used to establish a standard curve for determining the molecular weight of CAR-CBA. The effects of two critical factors, namely columns and eluents,on the molecular weight measurement of CAR-CBA were investigated to optimize the GPC quantitative method. The results showed that Ultrahydrogel columns(120, 250) and HAc–NaAc(0.5 M, pH 4.5) buffer solution were the optimal column and GPC eluent, respectively.The molecular weight of the synthesized CAR-CBA was analyzed by the optimized GPC method and determined to be 24.66 kDa.

Weighted Self-Adaptive Threshold Wavelets for Interpolation Point Selection Used in Interconnect MOR

As process technology development,model order reduction( MOR) has been regarded as a useful tool in analysis of on-chip interconnects. We propose a weighted self-adaptive threshold wavelet interpolation MOR method on account of Krylov subspace techniques. The interpolation points are selected by Haar wavelet using weighted self-adaptive threshold methods dynamically. Through the analyses of different types of circuits in very large scale integration( VLSI),the results show that the method proposed in this paper can be more accurate and efficient than Krylov subspace method of multi-shift expansion point using Haar wavelet that are no weighted self-adaptive threshold application in interest frequency range,and more accurate than Krylov subspace method of multi-shift expansion point based on the uniform interpolation point.

A Computational Synthesis Approach of Mechanical Conceptual Design Based on Graph Theory and Polynomial Operation

The design synthesis is the key issue in the mechanical conceptual design to generate the design candidates that meet the design requirements.This paper devotes to propose a novel and computable synthesis approach of mechanisms based on graph theory and polynomial operation.The graph framework of the synthesis approach is built firstly,and it involves:(1)the kinematic function units extracted from mechanisms;(2)the kinematic link graph that transforms the synthesis problem from mechanical domain into graph domain;(3)two graph representations,i.e.,walk representation and path representation,of design candidates;(4)a weighted matrix theorem that transforms the synthesis process into polynomial operation.Then,the formulas and algorithm to the polynomial operation are presented.Based on them,the computational flowchart to the synthesis approach is summarized.A design example is used to validate and illustrate the synthesis approach in detail.The proposed synthesis approach is not only supportive to enumerate the design candidates to the conceptual design of a mechanical system exhaustively and automatically,but also helpful to make that enumeration process computable.

Correlation between hydrocarbon distribution and water-hydrocarbon ratio in Fischer-Tropsch synthesis

In order to shorten the evaluation cycle of cobalt catalyst before the optimized catalyst is fixed on, a mathematical method is proposed to calculate weight percentage of C5＋ hydrocarbons. Based on the carbide polymerization mechanism and the main hydrocarbons being linear alkanes and α-olefins, the correlation between hydrocarbon distribution and the molecular mass ratio of water to hydrocarbons is discussed. The result shows the ratio was within the range of 1.125-1.286 and the lower the ratio, the more gaseous hydrocarbons were obtained. Moreover, a linear equation between the weight percentage of C5＋ hydrocarbons and the weight ratio of C5＋ hydrocarbons to the total water is established. These results are validated by corresponding experiments. The weight percentage of C5＋ hydrocarbons could be immediately calculated by this linear equation without detailed gas chromatography （GC） analysis of them.

The 218th amino acid change of Ser to Ala in TaAGPS-7A increases enzyme activity and grain weight in bread wheat

ADP-glucose pyrophosphorylase(AGPase)influences cereal productivity.There are few reports on the function of cytosolic AGPase small subunit in bread wheat(TaAGPS).In the present study,TaAGPS was preferentially expressed in developing endosperm during grain-filling stages in bread wheat.TaAGPS allelic variations were characterized in 143 wheat accessions by PacBio RS II sequencing.Two haplotypes(TaAGPS-7A-TG and TaAGPS-7A-CT)of TaAGPS-7A were identified and corresponding functional markers were developed,whereas no variants of TaAGPS-7B and TaAGPS-7D were detected.TaAGPS-7A was associated with thousand-kernel weight(TKW)by haplotype–trait association analysis in two populations.Near-isogenic lines(NILs)with TaAGPS-7A-TG showed higher TKW and total kernel starch content than those with TaAGPS-7A-CT,owing to the higher AGPase activity of TaAGPS-7A-TG than TaAGPS-7A-CT both in vitro and in vivo.Overexpression of TaAGPS-7A-TG in bread wheat doubled the transcription levels of TaAGPS and increased AGPase activity by 55.7%,resulting in a 3.0-g higher TKW than in the wild type(WT).Knockdown of TaAGPS led to reduced expression of TaAGPS,AGPase activity,and TKW than in the WT.Thus,owing to the 218th amino acid change of Ser to Ala in TaAGPS-7A,the favorable haplotype TaAGPS-7A-TG showed higher AGPase activity,resulting in higher kernel starch content and grain weight.This finding could be applied to increasing starch content and grain weight in bread wheat.

A New Synthesis Method for Sum and Difference Beam Pattern with Low Sidelobe

A new method for sum and difference beam pattern synthesis with low sidelobe is proposed.In the situation of phase taper weighting,it makes use of Fourier transform pair relationship existing between the array factor and the element excitations and uses a loop iterative way to derive the array element excitations according to given array factor.The iteration does not stop until the array element excitations meet the initial sidelobe requirements.The method overcomes the defects of traditional methods,such as more searching times,larger amount of calculation and poor robustness.In addition,it can also synthesize the low sidelobe pattern in case of element failures.Simulation verifies the effectiveness of the method.

联合傅里叶卷积与通道注意力的光场角度重建

光场相机能够同时捕获光线的强度和方向信息,但由于成像传感器尺寸的限制,无法同时获得高空间和角度分辨率的光场图像。提出了一种联合傅里叶卷积和通道注意力的光场角度重建方法,通过使用稀疏光场图像4个边角位置的参考视图,可以间接地重建出密集光场图像。考虑到光场数据的内在4D结构,采用通道级密集快速傅里叶残差卷积块,在空域和频域对光场图像的空间和角度相关性进行建模,然后采用基于全局响应归一化的通道注意块,以实现通道间的自适应融合。此外,还提出了一种改进的视点加权间接合成方法,通过为每个参考视图分配一个置信图,为参考视图之间建立联系以合成更真实的新视图。实验结果表明,相比于现有先进的光场角度重建算法IRVAE,所提方法的重建光场图像质量在自然光场数据集30Scenes,Occlusion和Reflective上的平均PSNR分别提高了0.08,0.13和0.13 dB。所提方法在保证光场角度一致性的前提下取得了清晰的重建结果。

多模式低副瓣阵列方向图综合方法

本文面向阵列天线低副瓣的实际应用需求,利用空时编码的思路设计加权矢量,分别提出序贯快速傅里叶变换(fast Fourier transform,FFT)方法、约束方程计算方法和优化函数求解方法,对应多脉冲低副瓣方向图综合时加权矢量时变、不变和奇偶交替变的3种不同工作模式。理论分析和仿真实验表明,序贯FFT和约束方程计算方法均能实现超低副瓣方向图(优于-50 dB),而优化函数求解方法在实现低副瓣的同时仍能保持方向图主瓣的良好性能,避免了传统方向图综合方法无法同时兼顾主副瓣性能的缺点。另外,从计算复杂度、随机幅相误差、干扰抑制等各方面综合分析了不同方法的优缺点,可为实际阵列天线的工程应用提供理论指导和技术参考。

基于变权模糊综合法与人工神经网络的地铁车辆转向架系统健康状态评价

[目的]相较于现代地铁车辆普遍采用的计划修和故障修的维修模式,状态修可以在优化维修策略和成本的同时,把握车辆系统的健康状态和运行情况。为实现状态修,需对车辆系统健康状态进行准确评价。[方法]以地铁车辆转向架系统为对象,对其健康状态的评价方法进行深入研究。依据转向架系统组成具有层次性的特点,以劣化度为依据,将层次分析法和变权理论相结合,根据模糊综合评判思路,建立基于劣化度的地铁车辆转向架健康状态变权模糊综合评价模型,提出建模流程;通过选取的地铁车辆转向架系统健康状态评价指标对其进行健康状态评估,获得样本数据;利用样本数据对BP神经网络、支持向量机和随机森林三种不同的人工神经网络进行训练,利用实际测试数据判断三种不同类型人工神经网络的评价效果。[结果及结论]随机森林模型对地铁车辆转向架系统健康状态的识别能力最强,可实现对地铁车辆转向架系统的智能化健康评估。

提升杭州城市国际化水平的对策研究——基于指数测评

为全面了解杭州城市国际化进程,本文题运用线性加权综合法从经济发展水平、城市产业结构、基础设施水平、城市产业发展、对外交流5大维度进行指数测算。通过定性与定量研究分析,全面评价杭州市城市国际化进程中的优势和短板,提出加速推进杭州城市国际化的建议。

改进层次分析法-熵权法在周口市地下水资源承载力评价上的应用

地下水资源承载力是衡量当地社会、经济可持续发展及生态环境良性发展的重要指标,现如今对我国地下水资源承载力综合评价的需求迫在眉睫。目前地下水资源承载力评价方法多样,成果众多,但仍没有最优评价方法。周口市水资源丰富,但人均占有量少,污水排放较多,水体污染严重且水资源承载力研究十分匮乏。针对以上问题,选取适合研究区域地下水资源评价的主要指标,采用层次分析法和熵权法分别确定指标权重,利用乘法合成计算出组合权重,最后通过模糊综合评价法对周口市水资源承载力进行评价。结果表明,周口市地下水资源承载力处于良好状态,其承载力总体处于上升趋势。

非穿透型齿根裂纹应力强度因子权函数法求解

齿轮齿根是具有非穿透性的三维裂纹,其应力强度因子计算求解难度大且过程复杂。对此应用片条合成权函数法将三维裂纹问题转化为一系列“等效的”薄片单元二维裂纹问题。根据作用在薄片单元上的法向力按照其啮合刚度进行分配,求出作用于每个薄片单元上的法向力,再运用二维裂纹权函数法计算每个薄片单元裂纹应力强度因子。其求解结果与有限元法计算结果十分吻合,最大误差为3.9%。

N,N'-二(4,6-二氨基酸基-1,3,5-三嗪基)-己二胺的合成及缓蚀性能

以三聚氯氰为母体,接入氨基酸(2-氨基乙酸、3-氨基丙酸、4-氨基丁酸、6-氨基己酸)和1,6-己二胺,设计、合成了N,N’-二[4,6-二(2-氨基乙酸基)-1,3,5-三嗪基]-己二胺(TFYJ)、N,N’-二[4,6-二(3-氨基丙酸基)-1,3,5-三嗪基]-己二胺(TFBJ)、N,N’-二[4,6-二(4-氨基丁酸基)-1,3,5-三嗪基]-己二胺(TFDJ)、N,N’-二[4,6-二(6-氨基己酸基)-1,3,5-三嗪基]-己二胺(TFJJ)4个缓蚀剂。利用FTIR、1HNMR、MS对其结构进行了表征。通过静态失重法、电化学法测试了45#碳钢在1mol/L盐酸中的缓蚀性能,量化计算了TFJJ的最高占据分子轨道能量值、最低未占据分子轨道能量值、Fukui指数,分析了缓蚀机理。结果表明,4个目标缓蚀剂在1 mol/L盐酸中对45#碳钢表现出优异的缓蚀效果。20℃下,质量浓度为100 mg/L的TFJJ缓蚀率达到了98.37%(失重法)。制备的缓蚀剂是以阴极为主的混合型缓蚀剂。TFJJ符合Langmuir等温吸附方程,是以化学吸附为主的自发过程,其缓蚀作用发生在三嗪环和氨基上的N原子及羧酸基团上的C、O原子上。与市售缓蚀剂NEUF485相比,合成的产品缓蚀率提高了5.90%~10.62%,TFJJ在质量浓度为600 mg/L的硬水下仍具有良好的耐硬水性。

基于BIM技术的高层建筑工程施工安全评估方法研究

现有的高层建筑工程施工安全评估忽略了不同施工阶段评估指标的变化情况,本文提出基于BIM技术的高层建筑工程施工安全评估方法研究。选取REVIT软件结合高层建筑工程施工的特征,确定BIM建模标准,构建高层建筑工程施工模型,选取施工安全评估指标,基于博弈组合赋权法确定评估指标的常权权重,采用变权综合法,动态修正常权权重,获得评估指标的变权权重,构造施工安全综合评估方程,确定施工安全评估等级,从而实现高层建筑工程施工安全的评估。通过实验获得的施工安全评估结果与实验项目实际情况相符,证明提出方法具备可行性与实用性。

TabHLH95-TaNF-YB1 module promotes grain starch synthesis in bread wheat

Starch is the most abundant substance in wheat(Triticum aestivum L.)endosperm and provides the major carbohydrate energy for human daily life.Starch synthesis-related(SSR)genes are believed to be spatiotemporally specific,but their transcriptional regulation remains unclear in wheat.Here,we investigate the role of the basic helix-loop-helix(bHLH)transcription factor TabHLH95 in starch synthesis.TabHLH95 is preferentially expressed in the developing grains in wheat and encodes a nucleus localized protein without autoactivation activity.The Tabhlh95 knockout mutants display smaller grain size and less starch content than wild type,whereas overexpression of TabHLH95 enhances starch accumulation and significantly improves thousand grain weight.Transcriptome analysis reveals that the expression of multiple SSR genes is significantly reduced in the Tabhlh95 mutants.TabHLH95 binds to the promoters of ADP-glucose pyrophosphorylase large subunit 1(AGPL1-1D/-1B),AGPL2-5D,and isoamylase(ISA1-7D)and enhances their transcription.Intriguingly,TabHLH95 interacts with the nuclear factor Y(NF-Y)family transcription factor TaNF-YB1,thereby synergistically regulating starch synthesis.These results suggest that the TabHLH95-TaNF-YB1 complex positively modulates starch synthesis and grain weight by regulating the expression of a subset of SSR genes,thus providing a good potential approach for genetic improvement of grain productivity in wheat.

基于熵权模糊综合法的建筑工程造价风险管理研究

随着我国建筑业的蓬勃发展,建设工程项目的数量与日俱增。由于工程项目在建设过程中的诸多不可预见性,工程风险无处不在,因此将风险管理应用于造价管理中就显得尤为重要。本文从建筑工程的决策阶段、设计阶段、发承包阶段、施工阶段及竣工阶段出发,对全过程造价中存在的风险进行分析,并依据熵权模糊综合法构建风险评价模型。最后对工程实例进行风险评价,识别出了对工程造价影响的关键阶段,为建设单位进行造价风险管理提供参考。

基于非对称泰勒综合的平面阵列低副瓣设计

根据平面相控阵高灵活性低副瓣的需求,提出了一种基于非对称泰勒综合的平面阵列加权方法。相比于现存的主流方法,该方法适用于任意阵元排布的平面阵列,可对辐射方向图进行非对称的副瓣控制,还具有天线增益损失较小、幅度和相位同时加权、算法为非迭代算法等优点。给出了对称和非对称的泰勒加权公式,以及在不同阵面排布下的降副瓣效果。仿真结果表明该方法速度快,灵活度高,性能稳定。

基于MADM与模糊综合评价的异构无线网络选择算法

针对接入网选择中出现的负载不均衡和失序问题,提出了一种基于MADM与模糊综合评价的异构无线网络选择算法,算法基于不同类型用户群的业务和偏好,利用MADM中的熵权法和层次分析法分别计算四种业务类型下的主客观权重,当用户以服务质量为优先选网策略时,采用乘法合成法融合权重;当用户以价格为偏好时,利用线性加权法进行组合赋权。最后通过模糊综合评价计算四种业务类型下基于两种用户偏好的网络得分,进行接入网决策。仿真结果表明,采用不同的权重组合策略去满足不同的用户选网偏好,与单一的权重融合方法相比,能够较好地均衡网络负载;与TOPSIS排序法相比,提出的模糊综合评价算法准确率更高,均衡负载的性能更好,且避免了接入网选择过程中产生的失序问题。