早老素-1基因启动子区-48C/T位点多态性与LOAD的遗传相关性

目的 研究早老素 - 1基因启动子区 - 4 8C/T位点的多态性与迟发性AD(LOAD)的相关性。方法 用常规方法从人外周血白细胞中抽提基因组DNA ,PCR扩增出包含 - 4 8C/T多态性位点的基因片段 ,利用PCR -RFLP技术对 -4 8C/T多态性位点进行基因分型 ,χ2 检验分析 - 4 8C/T多态性位点基因型分布和等位基因频率。结果 以 33例AD病例和32例对照样品的外周血白细胞基因组DNA为模板 ,PCR扩增出了长度为 344bp的包含 - 4 8C/T多态性位点的基因片段。基因分型结果表明 ,33例散发型AD的C和T等位基因频率分别为 4 7%和 5 3% ,C/T和T/T基因型频率分别为 94 %和 6 %。而 32例正常对照的C和T等位基因频率分别为 4 8%和 5 2 % ,C/T和T/T基因型频率分别为 97%和 3%。χ2 检验结果显示 ,病例 -对照样品间C和T等位基因频率及C/C、C/T和T/T基因型的分布均无显著性差异 (χ2 值分别为 0 4 4 3和 0 318,P>0 .0 5 )。结论 在我们研究的群体中 ,早老素 - 1基因启动子区 - 4 8C/T位点的多态性与LOAD无显著的遗传相关性。

Topology optimization of 3D structures with design-dependent loads

Topology optimization of continuum structures with design-dependent loads has long been a challenge. In this paper, the topology optimization of 3D structures subjected to design-dependent loads is investigated. A boundary search scheme is proposed for 3D problems, by means of which the load surface can be identified effectively and efficiently, and the difficulties arising in other approaches can be overcome. The load surfaces are made up of the boundaries of finite elements and the loads can be directly applied to corresponding element nodes, which leads to great convenience in the application of this method. Finally, the effectiveness and efficiency of the proposed method is validated by several numerical examples.

Numerical study on wave loads and motions of two ships advancing in waves by using three-dimensional translating-pulsating source

A frequency domain analysis method based on the three-dimensional translating-pulsating （3DTP） source Green function is developed to investigate wave loads and free motions of two ships advancing on parallel course in waves. Two experiments are carried out respectively to mea- sure the wave loads and the free motions for a pair of side-by- side arranged ship models advancing with an identical speed in head regular waves. For comparison, each model is also tested alone. Predictions obtained by the present solution are found in favorable agreement with the model tests and are more accurate than the traditional method based on the three dimensional pulsating （3DP） source Green function. Numer- ical resonances and peak shift can be found in the 3DP pre- dictions, which result from the wave energy trapped in the gap between two ships and the extremely inhomogeneous wave load distribution on each hull. However, they can be eliminated by 3DTP, in which the speed affects the free sur- face and most of the wave energy can be escaped from the gap. Both the experiment and the present prediction show that hydrodynamic interaction effects on wave loads and free motions are significant. The present solver may serve as a validated tool to predict wave loads and motions of two ves- sels under replenishment at sea, and may help to evaluate the hydrodynamic interaction effects on the ships safety in replenishment operation.

Large deflections of non-prismatic nonlinearly elastic cantilever beams subjected to non-uniform continuous load and a concentrated load at the free end

This work studies large deflections of slen- der, non-prismatic cantilever beams subjected to a combined loading which consists of a non-uniformly distributed con- tinuous load and a concentrated load at the free end of the beam. The material of the cantilever is assumed to be non- linearly elastic. Different nonlinear relations between stress and strain in tensile and compressive domain are considered. The accuracy of numerical solutions is evaluated by com- paring them with results from previous studies and with a laboratory experiment.

Effect of Mild-calcined Coal Gangue Additionon Hot Strength and Refractoriness Under Loadof Ultra Low Cement Castablesin Al_2O_3-SiO_2 System

This work explored the way to improve hot modulus q/＇ rupture （HMOR） and refractoriness under load （RUL） by adding mild-calcined coal gangue （MCG） in Al2O3 -SiO2 ultra low cement （ULC） castables, making use of the in-situ effect of the MCG during heating-up. The influence of respective additions of 5%, 10% and 1.5% of the MCG powders calcined at 700℃ was investigated on HMOR at 1400 ℃ and RUL of the castables. With increased addition of the MCG, HMOR and RUL become significantly enhanced. At 10% of the MCG addition, HMOR reaches 3 MPa, as compared to 0. 3 MPa in the case of no MCG addition. RUL of the specimens dried at 110 ℃for 24 h can be increased by some 270 ℃ with 10% of the MCG addition. RUL 0.11 the specimens preheated at 1 500℃ for 3 h maintains the growth trend with the MCG addition increasing. The microstructure of the heated castable samples was investigated by means of SEM. The in-situ formed needle-like and interlaced mullite in the matrix is contributive to the tmprovement.

Non-stationary Buffeting Response Analysis of Long Span Suspension Bridge Under Strong Wind Loading

The non-stationary buffeting response of long span suspension bridge in time domain under strong wind loading is computed. Modeling method for generating non-stationary fluctuating winds with probabilistic model for non-stationary strong wind fields is first presented. Non-stationary wind forces induced by strong winds on bridge deck and tower are then given a brief introduction. Finally,Non-stationary buffeting response of Pulite Bridge in China,a long span suspension bridge,is computed by using ANSYS software under four working conditions with different combination of time-varying mean wind and time-varying variance. The case study further confirms that it is necessity of considering non-stationary buffeting response for long span suspension bridge under strong wind loading,rather than only stationary buffeting response.

DL/T645-2007《多功能电能表通信协议》的技术特点和创新

介绍了DL/T 645-2007《多功能电能表通信协议》制订中考虑的主要问题,以及《多功能电能表通信协议》各部分主要变化和技术创新,同时讨论了兼容问题的对策。

基于Haar小波变换和ARIMA-RBF的天然气时负荷预测

针对天然气时负荷预测问题,提出了一种基于Haar小波变换和ARIMA-RBF的天然气时负荷组合预测模型。首先,对天然气时负荷数据样本时间序列进行小波分解,采用Mallat快速算法,母小波为Haar小波,对分解出来的高频分量进行ARIMA预测,低频分量进行RBF预测;其次,对高频分量预测结果和低频分量预测结果进行Haar小波重构;最后,以某市实际采集的天然气时负荷为例进行研究,并与自组织特征映射(Self-organizing Feature Map,SOFM)网络和多层感知器(Multilayer Perceptron,MLP)网络(SOFM+MLP)组合预测模型进行对比分析。结果表明,组合预测模型较SOFM+MLP预测模型的MAPE值指标高出2.593 2%,预测精度显著提高,为实际工程的在线应用提供了有益参考。

燃气三联供-热泵容量优化匹配分析方法

园区级综合能源系统中,燃气三联供和热泵在供冷(热)时均可优先选用,确定二者最佳的匹配容量是综合能源系统规划设计的重点之一。文中提出了一种通过解析法确定燃气三联供和热泵最佳匹配容量的方法。该方法基于各类设备单位装机容量在考察期内净现值的计算式,结合各负荷区间出现的频数统计,得到不同容量匹配方案下燃气三联供和热泵设备的年等效满负荷运行时数及相应的收益,通过比较考察期内系统总的净现值确定最优容量匹配方案。结合案例对本文所提出的分析方法进行了验证,指出推导分析法的优势在于可将最优结果产生的过程呈现,便于各参与方相机决策。

Interactive effects of irrigation and exponential fertilization on nutritional characteristics in Populus 3 euramericana cv. ‘74/76' cuttings in an open-air nursery in Beijing, China

Nutritional characteristics determine tree stock quality to a considerable extent. Exponential fertilization can induce nutrient reserves within juvenile trees, but its validity on poplar is contingent on interaction with a scientific irrigation regime due to limited water resources under global warming. In the present study, we raised 3200 Populus 9 euramericana cv. ＇74/76＇ cuttings under four irrigation regimes of 0（I0）, 60 %（I60）, 80 %（I80）, and100 %（I100） of field capacity for soil moisture content with or without（control） the employment of nitrogen（N） addition delivered as exponential fertilization at the rate of 8 g N cutting^（-1）（E8） in an open-air nursery in Beijing, China. Both height and diameter increased with the increment of soil moisture ratio or in response to exponential fertilization（EF） without any interactive effects. In general, concentrations of N, phosphorus（P）,and potassium（K） declined with time in stem but foliar N concentration did not change. Under the I100 regime, EF increased foliar N concentration relative to the control but failed to affect N concentration in stem in September, when both N concentration and N content were increased by EF under the I80 regime. Stem-K content and concentration by EF under the I80 regime also increased in September,therefore EF-treated cuttings had a higher ratio of K content in stem to that in whole plant（%ANAR）. Vector diagnosis for nutritional status indicated that EF resulted in dilution of K concentration but induced a steady-state P uptake in leaves under all irrigation regimes. Therefore, EF of N addition could promote N uptake to leaves of P. 9 euramericana cv. ＇74/76＇ cuttings, but it had a null effect on N and P reserves in stem and impaired K reserves.In conclusion, the irrigation regime of 80 % field capacity of soil moisture content was suggested for the culture of juvenile P. 9 euramericana cv. ＇74/76＇ cuttings. As the interactive meaning, EF was also suggested for its excellent promotion on both N and K uptakes.

Effects of fundamental structure parameters on dynamic responses of submerged floating tunnel under hydrodynamic loads

This paper investigates the effects of structure parameters on dynamic responses of submerged floating tunnel （SFT） under hydrodynamic loads. The structure parameters includes buoyancy-weight ratio （BWR）, stiffness coefficients of the cable systems, tunnel net buoyancy and tunnel length. First, the importance of structural damp in relation to the dynamic responses of SPT is demonstrated and the mechanism of structural damp effect is discussed. Thereafter, the fundamental structure parameters are investigated through the analysis of SFT dynamic responses under hydrodynamic loads. The results indicate that the BWR of SFT is a key structure parameter. When BWR is 1.2, there is a remarkable trend change in the vertical dynamic response of SFT under hydrodynamic loads. The results also indicate that the ratio of the tunnel net buoyancy to the cable stiffness coefficient is not a characteristic factor affecting the dynamic responses of SFT under hydrodynamic loads.

Influence of Thermal Load on Mechanical Property of Cemented Carbide Material and Heavy Cemented Carbide Inserts Life

A large amount of cutting heat is produced during the heavy cutting process,and insert life is restricted by the effect of thermal load.The thermal load experiment of cemented carbide SCS,WF and YT15 is carried out,and the results show that the bending strength and fracture toughness of cemented carbide material decrease obviously under cyclic thermal load,while in the cooling process,the material mechanical property changes worse suddenly.The high-temperature mechanical property of SCS is the most stable,and that of YT15 is the worst.Further,a relation model among cutting temperature,cutting parameters and insert life is established.Finally,the measures to improve heavy cemented carbide inserts life are summarized from the aspects of cutting parameters selection,insert optimization design and TiCN,Al2O3,TiN complex insert coating.The research results are expected to provide support and reference for heavy cutting technology and insert technology.

血清BNP、D-D水平及24 h室性期前收缩负荷对心力衰竭患者心源性不良事件发生的预测价值研究

目的探讨血清脑钠肽(BNP)、D-二聚体(D-D)水平及24 h室性期前收缩(PVC)负荷对心力衰竭患者心源性不良事件发生的预测价值。方法将该院2017年7月至2020年12月收治的82例心力衰竭患者作为观察组,同期50例入院排除心力衰竭的患者作为对照组。检测患者血清BNP和D-D水平,行24 h心电图检查,记录24 h PVC负荷。比较观察组与对照组、发生心源性不良事件与未发生心源性不良事件心力衰竭患者的BNP、D-D水平及24 h PVC负荷,分析血清BNP、D-D水平及24 h PVC负荷与心源性不良事件发生的关系及其预测心源性不良事件发生的价值。结果观察组血清BNP、D-D水平及24 h PVC负荷均明显高于对照组(P<0.05);发生心源性不良事件心力衰竭患者血清BNP、D-D水平及24 h PVC负荷均明显高于未发生心源性不良事件者(P<0.05);心力衰竭患者血清BNP、D-D水平及24 h PVC负荷与心源性不良事件发生均呈正相关(r=0.743、0.611、0.658,P<0.05);BNP、D-D及24 h PVC负荷联合检测预测心源性不良事件发生的灵敏度、特异度及曲线下面积均明显高于各项指标单独检测(P<0.05)。结论联合分析BNP、D-D水平及24 h PVC负荷变化可有效预测心力衰竭患者心源性不良事件的发生,具有较高的临床应用价值。

Obtaining vehicle parameters from bridge dynamic response:a combined semi-analytical and particle filtering approach

Dynamic load imposed on the bridge by mov- ing vehicle depends on several bridge-vehicle parameters with various uncertainties. In the present paper, particle filter technique based on conditional probability has been used to identify vehicle mass, suspension stiffness, and damping including tyre parameters from simulated bridge accelerations at different locations. A closed-form expres- sion is derived to generate independent response samples for the idealized bridge-vehicle coupled system consider- ing spatially non-homogeneous pavement unevenness. Thereafter, it is interfaced with the iterative process of particle filtering algorithm. The generated response sam- ples are contaminated by adding artificial noise in order to reflect field condition. The mean acceleration time history is utilized in particle filtering technique. The vehicle- imposed dynamic load is reconstructed with the identified parameters and compared with the simulated results. The present identification technique is examined in the presence of different levels of artificial noise with bridge response simulated at different locations. The effect of vehicle velocity, bridge surface roughness, and choice of prior probability density parameters on the efficiency of the method is discussed.

基于K-均值聚类算法的大客户用电行为分析

为掌握大客户的用电习惯和用电特征、满足不断变化的客户用电需求、逐步提升大客户领域供电服务水平,本文采用K-均值聚类算法、二八定律、归一化算法等统计分析方法,运用SPSS等数学分析工具,从行业特点、客户价值、用电需求、成长性等方面刻画用电客户群体特征,挖掘大客户用电数据中的隐藏数据和潜在价值,得出五类典型的大客户用电负荷特征曲线,建立对应的五类典型用户分类,得到了五类用电行为特征的结果,通过结果分析得出半数以上用户的用电特点、同类型的船舶制造业仍然具有不同的用电特点、电能紧张时优先对建筑业和采矿业实施有序用电可以取得较好效果,最终对企业的电力营销和调度进行决策支撑,为用电需求侧管理、优化客户服务管理规范提供辅助决策。

Investigation of the factors affecting the consistency of short-period traffic counts

The main intent of this study is to investigate the accuracy of short-duration traffic counts conducted during winter months. The investigation is based on 11-year sample data collected using permanent traffic counters at various locations in Alberta, Canada. Four types of road sites： commuter, regional commuter, rural long-distance, and recreational sites are studied. The sample data consti- tute six different durations of counts （12-, 24-, 48-, 72-, 96-h, and 1 week） taken during summer and winter months. The coefficient of variation （CV） is used as the relative measure of deviation for counts of different dura- tions to measure the accuracy of short-period traffic counts. The study results indicate that 48-h count seems to be the most cost-effective counting interval during both summer and winter months. It is also found that the lowest values of CV result for counts taken at commuter sites, and the highest values are observed for recreational sites. Frequent changes in temperature and other weather events cause significant variation in traffic volume, which results in an increase in CV values for counts taken during winter months. The application of an adjustment factor to remove the effect of cold and snow from short-period counts is also included in this study. Introduced adjustment factors can reduce the values of CV for all counts taken during winter months. The findings of this study can lead highway agencies to improve the cost-effectiveness of their short- period traffic counting programs.

Evaluation of the Third 90 of the 90-90-90 Cascade for the Period 2019-2020 in the Central African Republic

Introduction In Central-African Republic, according to UNAIDS in 2019, out of approximately 100,000 people living with HIV, 70% (72,000) knew their HIV status and 47,000 (46%) were on ARV therapy;however, there is a paucity of data on viral load suppression in people on ARV therapy. The objective of this study was to assess the third 90 of the UNAIDS strategy for the years 2019 and 2020 in the CAR. Methods We analyzed the available viral load data extracted from the data base of the medical analysis laboratory (SYSLAM) of the Institut Pasteur of Bangui for the years 2019 and 2020. The viral loads were determined based on plasma collected in an EDTA tube with Cepheid’s GeneXpert® 16-module controllers. Viral load data were extracted from SYSLAM, converted to Excel format, and analyzed with STATA version 14 software. The significance threshold for the statistical tests was set at 5%. Results This study included 22,895 patients, of who 72% were female. The average age was 40.82 years, and the majority of the patients (80%) came from the city of Bangui. Regarding the virological parameters associated with this study, 66% of the patients had significant viral load suppression according to the WHO recommendations and 34% were in virological failure. Patients over 50 years of age (71.85%) and age group 40 - 49 years (69.25%) recorded significant levels of viral load suppression. On the other hand, 63.45% of patients under 18 years of age had virological failure. All of these results were statistically significant (p < 0.005). Conclusion There should be a concerted effort, to make viral load accessible and available to all patients receiving ARV treatment in the CAR and the management of HIV/AIDS infection of children and adolescents should be given special attention.

EXACT SOLUTION FOR RECTANGULAR SLAB WITH THREE EDGES SIMPLY-SUPPORTED AND OTHER FREE

In this paper,we give all-sided pastic analysis of the rectangular slab with three edges simply-supported and other free.Here we discuss the following four cases:(1)The uniformly distributedload over the area a slab.(2).A concentrated load act at midpoint of free edges slab.(3)A concen-trated load act at the center a slab.(4)The line load act along free edge of slab.

解析IEC 60601-1-3在加载状态下泄露辐射的测量要求和测量方法

本文先介绍了IEC 60601-1-3,Ed.2.0,12.4章对诊断X射线设备在加载状态下的泄漏辐射的测量要求和测量方法,然后针对该标准的12.4章的测试要求和测试方法中容易忽视或搞错,但又影响测量结果的要点进行了解析,最后通过一个例子归纳总结了IEC 60601-1-3对诊断X射线设备加载状态下的泄露辐射的测量方法,也指出了正确测量诊断X射线设备在加载状态下的泄露辐射的重要意义。

基于PVsyst软件模拟发电量数据的光伏电站电能损耗的分析方法研究

电能损耗是光伏电站非常重要的综合性指标,对其进行分析可以为光伏电站能效管理提供数据支持。在电能损耗的计算过程中,最大负荷损耗小时数的选取非常关键。提出了一种基于PVsyst软件模拟所得的发电量数据来分析光伏电站电能损耗的方法,结合工程实际情况给出了精确计算年最大负荷损耗小时数的改进算法数学模型,并对采用不同算法得到的年最大负荷损耗小时数进行了比较分析;以山西省大同市鸦儿崖乡100 MW光伏电站为算例,对其电气设备及线缆的电能损耗进行详细分析,验证了所提出光伏电站电能损耗分析方法的正确性。研究结果表明:1)由于光伏电站容配比的影响,应分别计算光伏电站直流侧和交流侧的年最大负荷损耗小时数,直流侧和交流侧的电能损耗也需要分别计算。2)该方法基于PVsyst软件模拟得到的光伏电站全年各小时的发电量数据,可准确计算出光伏电站的年最大负荷损耗小时数,在数学逻辑上合理,可以提高光伏电站电能损耗计算的准确度。该方法也可应用于其他实际运行的发电项目的电能损耗分析。