基于数值模拟的等跨连续梁桥冲击系数研究

本文为确定等跨连续梁桥的冲击系数,根据结构静力分析,求取边跨及中跨跨中挠度静力响应;基于结构动力学原理,分别建立车辆与桥梁的动力方程,采用五轴十三自由度平面车辆模型,三跨连续梁桥模型,建立车桥耦合振动方程,采用ANSYS和MATLAB软件编译等跨连续梁桥车桥耦合分析模块,迭代求解边跨及中跨跨中挠度动力响应;再依据冲击系数计算公式求出边跨及中跨冲击系数,确定桥面不平整度、速度、基频和载重这4个因素为影响因素,利用SPSS (statistical package for the social sciences)数值分析软件进行逐步回归,得到了各参数对冲击系数的显著程度,给出等跨连续梁桥挠度冲击系数计算公式。结果表明:桥面不平整度与挠度冲击系数的相关性较好,而速度、基频和载重对挠度冲击系数的线性相关较为不显著;回归分析结果显示,桥面不平整度与冲击系数之间的标准化相关系数Beta达到0.908,表明桥面不平整度对连续梁桥的冲击系数具有重要影响。然而,现行规范未考虑到这一因素,因此建议在后续规范修订中纳入桥面不平整度的影响。

调控生鲜猪肉过冷保鲜的逐步降温循环程序构建

为实现生鲜猪肉在冰点以下稳定过冷贮藏,本研究分析了逐步降温过程中初始温度和降温时间间隔对生鲜猪肉过冷的影响,构建调控生鲜猪肉过冷的最佳逐步降温循环程序,并评估生鲜猪肉在此条件下贮藏12 d的保鲜效果。结果表明,降温时间间隔显著影响生鲜猪肉的过冷点和过冷度。相较于12和18 h降温时间间隔组,6 h降温时间间隔组样品的过冷点显著降低、过冷度显著升高。在此基础上确定初始温度-1.5℃、降温时间间隔6 h、最低温度-3.5℃的逐步降温循环为调控生鲜猪肉过冷的最佳程序,此程序下贮藏12 d时生鲜猪肉过冷率达100%。与-3.5℃组冻结样品相比,各逐步降温循环程序显著降低了贮藏12 d样品的汁液流失率,延缓了猪肉中结合水和不易流动水向自由水的转化,提高了猪肉的持水力。相比-1至-3.5℃组,更低温度的-1.5至-3.5℃、-2至-3.5℃逐步降温循环程序可有效抑制贮藏期间生鲜猪肉中微生物的生长,延缓蛋白质腐败降解、更好地保持样品的新鲜度,且上述两组样品的挥发性盐基氮(TVB-N)和硫代巴比妥酸反应物(TBARS)含量与-3.5℃组样品无显著差异。该研究可为高品质生鲜肉的新型贮藏保鲜技术开发和设备开发提供科学依据,进而促进我国生鲜肉冷链物流的发展。

基于渐进机器学习的中文问句匹配方法

问句匹配旨在判断不同问句的意图是否相近.近年来,随着大型预训练语言模型的发展,利用其挖掘问句对在语义层面隐含的匹配信息,取得了目前为止最好的性能.然而,由于基于独立同分布假设,在真实场景中,这些深度学习模型的性能仍然受制于训练数据的充足程度和目标数据与训练数据之间的分布漂移.本文提出一种基于渐进机器学习的中文问句匹配方法.该方法基于渐进机器学习框架,从不同角度提取问句特征,构建融合各类特征信息的因子图,然后通过迭代的因子推理实现从易到难的渐进学习.在特征建模中,设计并实现了两种类型特征的提取:(1)基于TF-IDF(Term frequency-inverse document frequency)的关键词特征;(2)基于DNN(Deep neural network)的深度语义特征.最后,通过通用的基准中文数据集LCQMC和BQ corpus验证了所提方法的有效性.实验表明,相比于单纯的深度学习模型,基于渐进机器学习的方法可以有效提升问句匹配的准确率,且其性能优势随着标签训练数据的减少而增大.

英语短语动词的三要素——以away组成的含gradually之义的短语动词为例

从语义的角度来对短语动词进行系统地认知是一种科学的新理念、新方法。以短语动词中的副词或介词为主线来进行纵向的组群亦是切实可行的一种好方法。然后在横向上辨析相关的同义的短语。以三者的有机结合所形成的复合思维来加以认知则更具特色。由away组成的短语动词可表数个意义。含“gradually”之义时,所表意义为动状关系。

广东省名中医陈国成教授峻药缓投经验分析

峻猛药物治疗疑难杂病有其独特的效果,但同时易损伤人体,故古代医家提出峻药缓投概念。陈国成教授是广东省名中医,擅长中风、肩手综合征等疑难病症的治疗。陈教授长期从事中医药临床实践和科研工作,凭借深厚的中医药理论功底和丰富的临床经验,融合中医经典理论和现代医学思想,积累了丰富的峻药缓投的治疗经验,陈教授在此基础上探索出峻药制丸服用、峻药外用等缓投方式。笔者总结其抵当丸化裁抗栓丸和冰麝液经鼻吸入治疗缺血性中风、星夏止痛膏贴敷治疗肩手综合征的经验,表明峻药缓投理论在中医药临床中的应用方式多样,不仅包括内服、外敷等传统方式,还可配合现代手段治疗,并在中风病及其并发症中多有应用,疗效显著,今后可进一步探索其在其他疑难杂病上的应用,以求拓宽慢性疑难病治疗的思路。

Gradual solution heat treatment of AlSiCuMg cast alloys

The microstructure characteristics of AlSiCuMg cast alloys were studied withdifferent Cu content and the gradual solution treatment by DSC, SEM, TEM and mechanical method. Themelting point of alpha (Al) + Si decreases and polynary eutectic phases with low melting point formwith increase of Cu content. Gradual solution treatment includes two steps: solution treating nearthe melting point of polynary eutectic phase to take it dissolve first, and then increasing solutiontemperature to take the remainder copper intermetallics dissolved into alpha (Al). Grain boundariesmelting can be avoided by gradual solution treatment, even the maximum solution temperature isabove final solidification point, and the age hardening response increases correspondingly

A gradually descent method for discrete global optimization

In this paper, a new method named as the gradually descent method was proposed to solve the discrete global optimization problem. With the aid of an auxiliary function, this method enables to convert the problem of finding one discrete minimizer of the objective function f to that of finding another at each cycle. The auxiliary function can ensure that a point, except a prescribed point, is not its integer stationary point if the value of objective function at the point is greater than the scalar which is chosen properly. This property leads to a better minimizer of f found more easily by some classical local search methods. The computational results show that this algorithm is quite efficient and reliable for solving nonlinear integer programming problems.

ANALYSIS MODEL ON GRADUAL CHANGE PRINCIPLE OF EFFECT ZONES OF LAYER FACE FOR ROLLED CONTROL CONCRETE DAM

The effect zones of layer face for RCC （rolled control concrete） dam have gradual change characteristics. Based on the analysis thought of complex material, a model was built to analyze above principle of RCC dam by use of series-wound and shunt-wound connection. Some methods were proposed to determine the instantaneous Young＇s modulus, delayed Young＇s modulus and viscosity coefficient of effect zones of layer face. Above models and methods were used to mine the principle of gradual change of key calculation parameters which can response the characteristics of effect zones. The principle of gradual change was described. A model was established to analyze the threedimensional viscoelastic problem of RCC dam. Above programs were developed. The examples show that the proposed models and methods to determine the key calculation parameters of effect zones can reflect the status of RCC dam accurately.

Gradual Clamping Reduced Ischemia-Reperfusion Injury in an Isolated Rat Heart Model

Objectives: We hypothesized that the organisms and their organs or tissues could adapt themselves to the gradual changes of environment for surviving or reducing damage. This study explored whether gradual clamping (GC) could reduce myocardial ischemia-reperfusion (IR) injury in rat heart. Methods: Twelve rats were randomized to IR group and GC group, then the hearts were isolated and perfused with Langendorff apparatus. Before cardioplegia, the perfusion was stopped abruptly in IR group while slowly with 5-minute in GC group. The hearts were subjected to 30-minute ischemia and 60-minute reperfusion. The left ventricular develop pressure (LVDP) and systolic pressure (LVSP), the maximal rate of the increase and decrease of left ventricular pressure (+dp/dtmax, ﹣dp/dtmax) were measured by polygraph system at different time points. The recovery of the variables was expressed as the ratio of these values at individual time point after reperfusion to the baseline respectively. Results: The recovery of LVDP after reperfusion was better than that in IR group (P = 0.034). No significant difference in the recovery of LVSP, +dp/dtmax and ﹣dp/dtmax between groups was observed. Conclusions: Gradual clamping could improve the recovery of LVDP after IR, suggesting that gradual clamping could reduce myocardial IR injury.

The gradual subduction-collision evolution model of Proto-South China Sea and its control on oil and gas

This study involved outcrop,drilling,seismic,gravity,and magnetic data to systematically document the geological records of the subduction process of Proto-South China Sea(PSCS)and establish its evolution model.The results indicate that a series of arc-shaped ophiolite belts and calcalkaline magmatic rocks are developed in northern Borneo,both of which have the characteristics of gradually changing younger from west to east,and are direct signs of subduction and collision of PSCS.At the same time,the subduction of PSCS led to the formation of three accretion zones from the south to the north in Borneo,the Kuching belt,Sibu belt,and Miri belt.The sedimentary formation of northern Borneo is characterized by a three-layer structure,with the oceanic basement at the bottom,overlying the deep-sea flysch deposits of the Rajang–Crocker group,and the molasse sedimentary sequence that is dominated by river-delta and shallow marine facies at the top,recording the whole subduction–collision–orogeny process of PSCS.Further,seismic reflection and tomography also confirmed the subduction and collision of PSCS.Based on the geological records of the subduction and collision of PSCS,combined with the comprehensive analysis of segmented expansion and key tectonic events in the South China Sea,we establish the“gradual”subduction-collision evolution model of PSCS.During the late Eocene to middle Miocene,the Zengmu,Nansha,and Liyue–Palawan blocks were separated by West Baram Line and Balabac Fault,which collided with the Borneo block and Kagayan Ridge successively from the west to the east,forming several foreland basin systems,and PSCS subducted and closed from the west to the east.The subduction and extinction of PSCS controlled the oil and gas distribution pattern of southern South China Sea(SSCS)mainly in three aspects.First,the“gradual”closure process of PSCS led to the continuous development of many large deltas in SSCS.Second,the deltas formed during the subduction–collision of PSCS controlled the development of source rocks in the basins of SSCS.Macroscopically,the distribution and scale of deltas controlled the distribution and scale of source rocks,forming two types of source rocks,namely,coal measures and terrestrial marine facies.Microscopically,the difference of terrestrial higher plants carried by the delta controlled the proportion of macerals of source rocks.Third,the difference of source rocks mainly controlled the distribution pattern of oil and gas in SSCS.Meanwhile,the difference in the scale of source rocks mainly controlled the difference in the amount of oil and gas discoveries,resulting in a huge amount of oil and gas discoveries in the basin of SSCS.Meanwhile,the difference of macerals of source rocks mainly controlled the difference of oil and gas generation,forming the oil and gas distribution pattern of“nearshore oil and far-shore gas”.

Gradual Band Energy to Passivate the Window Layer in Solar Cells

The passivation layers at the front of the cell are often referred as to the window layer because it must be transparent so as the solar cell has a high efficiency. In this work, numerical simulation has been proposed to study the effect of the AlGaAs gradual and normal windows on the cell sensitivity to the electron irradiation so as to passivate the solar cell. To expect the effect of gradual window layers, the J-V and P-V characteristics are confirmed better energy conversion performance of the illuminated solar cells after irradiation. The short circuit current Jsc and the open circuit voltage Voc are evaluated for different electron irradiation fluencies. The results show how the gradual window layer improves resistance to electron irradiation through its own parameters.

On the Gradualness by the Narrative Ambiguity in The Sound and The Fury

How to disambiguate the four narrators'narratives is the critical step to understand the whole work of The Sound and The Fury. With the gradualness produced by the ambiguous narrators'narration of juxtaposition of modern and traditional narration,another synchronized gradualness of Caddy is discovered,too. On the basis of deconstruction and psycho - analyses,rich and deep significance is illustrated by elucidation of narrative gradualness,as a new way to disambiguate the narrators'narration.

Gradual Bedside Reduction of Gastroschisis in a Resource Constrained Setting: Preliminary Results from 32 Cases

Introduction: Gastroschisis is one of the neonatal pathologies with bad prognosis in developing countries due to a lack of equipment. We aim to report one way of managing this malformation that could be practised everywhere, constituting an alternative approach to surgery in poor areas. Patients and Methods: This observational and descriptive study included newborn babies with gastroschisis who underwent gradual bedside reduction at the Paediatric Surgery Department of the Yaounde Central Hospital. Results: Our cohort was constituted by 32 newborn babies with a mean age of 18.12 hours on admission. The Lefort type 2 was the most frequent in 81.25% of cases. The mean time for oral feeding after complete reduction was 17.4 days and the duration of hospital stay was 24.91 days. Survival rates were at 40.63%, with a residual hernia after healing in 38.46% of cases. Conclusion: Despite the high rate of mortality, gradual reduction of gastroschisis at the bedside seems to be an opportunity for resource constrained areas and can be an alternative solution to surgery.

China's Science Gradually Strengthened

In order to ensure the steady development of our science, the Chinese government has continuously increased input in the last ten years. Information from the State Statistics Bureau shows that by the end of 1994, the national institutions and enterprises boasted 18.659 million technical experts, 4.3 times the number in 1978, or 1258 technical experts every ten thousand people, redoubling that of 1978. The whole country has 5860 independent scientific research and development (R & D) institutions,

Effects of Gradual Water Deficit Stress on Phenological and Morphological Traits in Chickpea （Cicer arietinum L.）

The aims of this study were to investigate the effect of gradual water deficit stress on some phonological and morphological traits and grain yield of desi and kabuli chickpea cultivars. This study was carried out in 2007 and 2008, to evaluate responses of three chickpea cultivars （Hashem and Arman from kabuli and Pirooz from desi type） under well watering （I1： 70mm evaporation from class A pan）, gradual water deficit （12 and 13： 70→90→ 110→130 and 70→100→130mm evaporation from class A pan, respectively） and severe water stress （14： 130mm evaporation from class A pan）. Result showed that days to flowering and plant height were decreased, as water limitation increased. This reduction was significant under gradual water stress （I2 and I3） and Severe water deficit （I4）, compared with control （I1）. There were no significant differences in grain filling period and grain yield among I~, I2 and I3 irrigation treatments. No significant differences in days to physiologic maturity and number of sub branches were recorded among irrigation treatments. Interactions of year×cultivar for days to physiologic maturity, grain filling period and grain yield （P≤0.01） and for days to flowering and plant height （P≤0.05） were significant. The superiority of Arman in producing comparatively greater grain yield could be attributed to higher grain filling period of this cultivar in both years.

行政法典化的渐进主义路径

行政法典是规范行政权和保护公民合法权益的最高级别的规范形式。法典化反映的是编纂法典的动态的发展趋势,其表现形式可以是多元化的,构造可以是多层次的,发展可以是渐进的、多阶段的。行政法典的理论构想包含行政法总则、行政基本法、行政程序法三种模式。行政法典化受行政法体系、立法成果、行政法理论以及文化等因素影响。从目标定位来看,要降低理想型、高级形态行政法典的预期,采取一种更为务实的局部性、适应性、渐进性、阶段性为特征的适度法典化的路径。在功能主义与渐进主义的双重视角下,把行政程序法作为行政基本法典的实现路径,更具有可行性和操作性。

基于“扶放有度”模式的“随机过程”项目式教学方法探索

该文利用“扶放有度”教学模式,结合项目式教学方法,对“随机过程”课程的教学方法进行了探索。以“随机过程”课程中的“平稳时间序列的预报”为例,将教学分为教师示证、教师辅导、同伴协作和独立表现四个阶段,在每个阶段对教学任务进行了精心设计,并且结合项目式教学方法在每个阶段增加了教学任务项目化环节,不但培养了学生的自主学习能力,还补充了学生的实践训练,实现了以学生为中心的教育理念,对于提高学生独立开展科学研究的能力具有重要作用。最后,该文还列出了几种提高研究生教学效果的方法。

大豆冠层叶片氮含量检测研究——基于无人机多光谱图像

为快速获取大豆冠层叶片氮素含量(Leaf Nitrogen Content,LNC)信息,采用无人机获取大豆冠层LNC多光谱影像光谱特征,通过分析光谱变量与LNC的相关性,选出对大豆冠层LNC敏感的光谱变量。利用逐步回归分析方法建立黑河43、龙垦310、龙垦3401在3个关键生育时期(R1、R3、R5)大豆LNC估测模型。研究结果表明:①在3个品种的3个生育期,除R5时期龙垦3401品种外,NDVI与LNC具有高度相关性,说明NDVI可以较好地进行大豆冠层LNC的反演。②在建模的过程中发现,在R1时期龙垦3401、黑河43、龙垦310所建模型的R2和RMSE依次为0.857、0.133,0.845、0.156,0.821、0.187;在R3时期龙垦3401、黑河43、龙垦310所建模型的R2和RMSE依次为0.835、0.204,0.881、0.113,0.849、0.162;在R5时期龙垦3401、黑河43、龙垦310所建模型的R2和RMSE依次为0.835、0.208,0.814、0.215,0.836、0.211。由此表明,利用无人机多光谱遥感图像数据可以很好地监测大豆LNC的空间分布情况。

小区尺度雨洪过程模拟及径流分配特性研究

为了研究小区尺度地表径流各组分占比随不同重现期降雨的变化规律,以西咸新区天福和园小区为研究对象,采用GAST-SWMM耦合模型,以模拟时长及地形边界条件为变量进行研究分析。研究表明:经两场实测降雨过程验证,模型确定性系数分别为0.83和0.82,表明构建的一二维耦合模型精度较高;在本文设置的两种工况下,小区地表径流外排率和管网排水率均随降雨重现期增大而以渐进曲线形式增大,土壤下渗占比和地表填洼率随降雨重现期增大而减小;小区地表径流外排和管网排水主要发生在降雨期间,分别占各自排水总量的94.88%和94.36%;小区地形边界条件对径流过程模拟的影响不容忽视,在有围墙及无围墙工况下平均地表径流外排率分别为9.42%、22.55%。本研究可为地势相对四周较低区域的排水防涝设计提供参考。