Repair of Second-Generation Recycled Fine Aggregate of Waste Concrete from Freeze-Thaw Environment by Carbonation Treatment

The reuse of waste recycled concrete from harsh environments has become a research hotspot in the field of construction.This study investigated the repair effect of carbonation treatment on second-generation recycled fine aggregate(SRFA)obtained from recycled fine aggregate concrete(RFAC)subjected to freeze-thaw(FT)cycles.Before and after carbonation,the properties of SRFA were evaluated.Carbonated second-generation recycled fine aggregate(CSRFA)at five substitution rates(0%,25%,50%,75%,100%)to replace SRFA was used to prepare carbonated second-generation recycled fine aggregate concrete(CSRFAC).The water absorption,porosity and mechanical properties of CSRFAC were tested,and its frost-resisting durability was evaluated.The results showed after carbonation treatment,the physical properties of SRFA was improved and met the requirements of II aggregate.The micro-hardness of the interfacial transition zone and attached mortar in CSRFA was 50.5%and 31.2%higher than that in SRFA,respectively.With the increase of CSRFA replacement rate,the water absorption and porosity of CSRFAC gradually decreased,and the mechanical properties and frost resistance of CSRFAC were gradually improved.Carbonation treatment effectively repairs the damage of SRFA caused by FT cycles and improves its application potential.

Effect of High Temperature Curing on the Frost Resistance of Recycled Aggregate Concrete and the Physical Properties of Second-Generation Recycled Coarse Aggregate under Freeze-Thaw Cycles

With the emphasis on environmental issues,the recycling of waste concrete,even recycled concrete,has become a hot spot in the field of architecture.But the repeated recycling of waste concrete used in harsh environments is still a complex problem.This paper discusses the durability and recyclability of recycled aggregate concrete(RAC)as a prefabricated material in the harsh environment,the effect of high-temperature curing(60℃,80℃,and 100℃)on the frost resistance of RAC and physical properties of the second generation recycled coarse aggregate(RCA_(2))of RAC after 300 freeze-thaw cycles were studied.The frost resistance of RAC was characterized by compressive strength,relative dynamic elastic modulus,and mass loss.As the physical properties of RCA_(2),the apparent density,water absorption,and crushing value were measured.And the SEM images of RAC after 300 freeze-thaw cycles were shown.The results indicated that the frost resistance of RAC cured at 80℃ for 7 days was comparable to that cured in the standard condition(cured for 28 days at 20℃±2℃ and 95%humidity),and the RAC cured at 100℃ was slightly worse.However,the frost resistance of RAC cured at 60℃ deteriorated seriously.The RAC cured at 80℃ for 7 days is the best.Whether after the freeze-thaw cycle or not,the RCA that curd at 60℃,80℃,and 100℃ for 7 days can also meet the requirements of Grade III RCA and be used as the aggregate of non-bearing part of prefabricated concrete components.RCA_(2) which is cured at 80℃ for 7 days had the best physical properties.

Curvelet变换在人脸识别中的应用研究

针对小波只能反映信号的点奇异性,无法实现人脸图像面部轮廓和五官曲线信息的最优稀疏表示,提出了一种基于第2代Curvelet的人脸识别算法.通过对人脸图像进行第2代Curvelet变换,分解得到表征人脸基本信息的低频系数,再利用双向2维主成分分析((2D)2PCA)进行降维,并结合最近邻算法进行人脸识别.以ORL人脸数据库进行试验,结果表明:与基于小波变换的算法相比,该算法具有更高识别率和更短的识别时间.

基于非抽取Curvelet变换的图像去噪算法

原始的Curvelet变换在Radon域用正交小波变换得到Curvelet系数,然而正交小波不具有平移不变性,所以会产生Gibbs震荡现象.提出用非抽取小波变换代替原始的Curvelet变换中的正交小波变换.非抽取小波的平移不变性和Curvelet变换的高度方向敏感性使得新算法成为图像去噪的一个很好的选择.使用数字非抽取Curvelet变换对添加了高斯白噪声的标准图像进行去噪.实验结果表明,新算法无论从峰值信噪比还是从视觉效果上都要优于小波去噪,普通Curvelet图像去噪和Wiener2滤波.而且新方法在去除噪声的同时还较好地保留了图像的边缘信息.

Alternating-current losses in two-layer superconducting cables consisting of second-generation superconductors coated by U-shaped ferromagnetic materials

Alternating-current losses in a two-layer superconducting cable, each layer being composed of 15 closely-spaced rectangular wires made up of second-generation superconductors when the ends of wires are coated by either a non-magnetic or strong ferromagnetic material having a U profile is numerically investigated. Computations are carried out through the finite-element method. The alternating-current losses do not increase significantly if the relative permeability of the coating is increased three orders of magnitude, provided that the current amplitude is less than half of the critical current in a superconducting wire. However, the losses are much higher for ferromagnetic coating if the amplitude of the applied current oscillating at 50 Hz is close to the critical current. The ferromagnetic coating is seen to accumulate the magnetic field lines normally on its surfaces, while the field lines are parallel to the long axes of the wires, leading to more significant flux penetration in the coated regions. This facilitates a uniform low-loss current flow in the uncoated regions of the wires. In contrast, coating with a non-magnetic material gives rise to a considerably smaller current flow in the uncoated regions, whereas the low-loss flow is maintained in the coated regions. Moreover, the current flows in opposite directions in the coated and uncoated regions, where the direction in each region is converse for the two materials.

Mutagenic Effects of Spaceflight Treatment on the Second-Generation Seeds of Alfalfa

[ Objective] To explore the effects of spaceflight on the second-generation seeds of alfalfa and provide a theoretical basis for mutation breeding. [Method] The seeds of Medicago stavia L. lines no. 1, no. 2 and no. 4 were carried into space by the Shijian-8 seed breeding satellite for a 15-d spaceflight treatment. After returning to the ground, seedlings were transplanted to field. Traits of the second-generation seeds of alfalfa were evaluated. [Result] The 1 000-grain weight of the second-generation seeds were 5% -9% significantly higher than that the control （P 〈 0.05）. The germination rate, seedling weight, shoot length and root length were significantly increased （P 〈 0.05）. The hard seed rate and the rate of moldy seeds were significantly decreased （ P 〈 0.05）. However, the rate of dead seeds was increased. [ Conclusion] Spaceflight treatment has positive mutagenic effects on the second-generation seeds of alfalfa.

Role of Second-Generation Drug-Eluting Stents and Bypass Grafting in Coronary Artery Disease:A Systematic Review and Meta-analysis

Background:The safety and efficacy of coronary artery bypass grafting(CABG)and second-generation drug-eluting stents(DESs)in patients with coronary artery disease(CAD)remain controversial.Therefore we aimed to compare the outcomes of CAD patients treated with CABG and second-generation DESs.Methods:We systematically searched the PubMed,Cochrane Library,Ovid,and Elsevier databases.Studies comparing second-generation DESs with CABG in CAD patients were included.RevMan 5.3 was used to extract and pool the data from the applicable studies.Results:Six trials(N=6604 participants)were included in this meta-analysis.Among all of the CAD patients,second-generation DESs were associated with no differences in the risks of all-cause death[risk ratio(RR)1.18,95% confi dence interval(CI)0.98–1.43,P=0.09],cardiovascular death(RR 1.14,95% CI 0.81–1.59,P=0.45),myocardial infarction(RR 1.22,95% CI 0.98–1.54,P=0.08),and stroke(RR 0.83,95% CI 0.59–1.17,P=0.29),but increased the risks of revascularization(RR 1.95,95% CI 1.66–2.30,P<0.001)and major adverse cardiac and cerebrovascular events(RR 1.72,95% CI:1.31–2.26,P<0.001)when compared with CABG.Conclusions:In the treatment of CAD patients,second-generation DESs was not associated with increased risks of all-cause death,cardiovascular death,myocardial infarction,and stroke,but increased the risks of revascularization and major adverse cardiac and cerebrovascular events when compared with CABG.

Thirty years of scientific research on second-generation antipsychotic drugs in Japan: A bibliometric analysis

Aims:Research on second-generation antipsychotic drugs (SGAs) has experienced great development in last decades.We did a bibliometric study on the scientific publications on SGAs in Japan.Methods: With theEMBASEandMEDLINEdatabases, we chose papers published from Japan with SGA descriptors. Price’s law and Bradford’s law has been used as bibliometric indicators for quantitating production and dispersion, respectively, of published papers on SGAs. We also calculated the participation index of different countries, and correlated those bibliometric data with some social and health data from Japan (such as totalper capitaexpenditure on health and gross domestic expenditure on research and development). Results: A sum of 669 original documents were published from Japan from 1982 to 2011. Those results fulfilled Price’s law, with scientific production on SGAs showing exponential growth (correlation coefficientr= 0.9261, as against anr= 0.8709 after linear adjustment). The most studied SGAs in Japan wererisperidone (n= 192), aripiprazole (n= 109), and olanzapine (n= 106). Division of documents into Bradford zones yielded a nucleus occupied exclusively by theProgress in Neuro-Psychopharmacology and Biological Psychiatry(49 articles). Those publications were in 157 different journals. Seven of the first 10 frequently used journals had an impact factor of being greater than 3. Conclusions: The SGA publications in Japan have been through exponential growth over the studied period, without evidence of reaching a saturation point.

棉蚜种群数量动态模型

本文以棉蚜为例,提出了蚜虫种群数量动态的通用模型,指出蚜虫在一年的生活周期中,从数量动态上可分为几个小周期.每个小周期皆由一个上升段及一个下降段构成,并且上升段是由逻辑斯蒂方程来描述,下降段是由反逻辑斯蒂方程来描述.最后用实际数据进行了拟合,说明其正确性与普遍性.

北京油鸡胚胎肝脏间充质干细胞的生物学特性

从7日龄北京油鸡胚胎肝脏中分离间充质干细胞,原代培养并传代至15代,免疫荧光法检测造血祖细胞/肝卵圆细胞的表面标志物CD34、CK19呈阴性表达;RT-PCR检测CD29、CD44、CD71、CD73呈阳性表达。尝试不同培养条件对细胞生长曲线的影响,选取最佳培养方案,同时对细胞进行细胞周期测定。肝脏间充质干细胞通过不同诱导液被成功诱导分化成脂肪细胞、心肌细胞,结果表明,从鸡胎肝中分离获得的间充质干细胞具有和人类间充质干细胞相似的生物学特性及分化潜能,其所具有多向分化的潜能,为今后临床广泛应用提供了可能。

基于恒定空间的地物演化规律

在地图制图中必须把三维空间中的地物投影到二维平面上。不同性质的地物之间存在着边界。地物的边界在二维平面上的投影为约当闭曲线。在时空中存在的地物具有演化的特性。地物的演化表现为地物的缩小、扩大、消失和新生。地物的演化可以通过边界的变换来实现。演化空间的恒定性是地物演化的普遍规律。

流曲线概念及造型方法

定义了一种可用于造型、具有明确流体力学意义的功能曲线——流曲线·将直匀流绕物面作二维无旋不可压缩定常流动时的流函数表达为曲面后,利用流函数曲面控制边界与流曲线的对应关系,采用拉普拉斯方程第一边值逆问题的数值解法,提出了来流为直匀流的流曲线造型方法并给出了实例·结果表明:流曲线定义及造型方法可用于与流体有关的平面曲线造型,可反映流场信息并对曲线的流体力学性能进行初步评估·

一种计算测井曲线齿中线的算法

齿中线是用于判定沉积相的比较重要的方法.首先提出了当数列中连续多个值相等且为极大值/极小值时,求中间极大值/极小值点的算法;然后提出了用于计算和判断齿中线形态的算法,该算法包括求曲线极大值和极小值、计算齿中线倾角、判决齿中线形态等步骤.经过在仿真数据上测试,表明改方法能够降低曲线中的噪声,并能够准确地检测到各个极大值和极小值点,在计算各个极值点的齿中线倾角后,能够判断齿中线的收敛类型.

工业用及服用PET纤维的模量-应变曲线及其分析

文章针对拉伸实验测试的高模低缩型PET工业丝和服用PET长丝的负荷-伸长曲线,进行计算转换得到纤维的模量-应变曲线。通过声速法和X射线衍射实验测试纤维的取向和结晶,结合纤维结构及纤维应用讨论了两种PET纤维的模量-应变曲线特点。

Long-term Outcomes of Primary Percutaneous Coronary Intervention with Second-generation Drug-eluting Stents in ST-elevation Myocardial Infarction Patients Caused by Very Late Stent Thrombosis

Background： The ST-segment elevation myocardial inthrction （STEMI） patients due to stent thrombosis （ST） remain a therapeutic challenge for a clinician. Till date, very few researches have been conducted regarding the safety and effectiveness of primary percutaneous coronary intervention （PCI） with second-generation drug-eluting stents （DES） for STEMI caused by very late ST （VLST）. This retrospective study evaluated the safety, efficacy, and outcomes of primary PCI with second-generation DES for STEM1 due to VLST compared with primary PCI for STEM1 due to de novo lesion. Methods： Between January 2007 and December 2013, STEMI patients with primary PCI in Fuwai Hospital had only second-generation DES implanted for de novo lesion （558 patients） and VLST （50 patients） were included in this retrospective study. The primary end points included cardiac death and reinfarction. The secondary end points included cardiac death, reinfarction, and target lesion revascularization. Continuous variables were expressed as mean （standard deviation） or median （interquartile range） and compared by Student＇s t-test or Mann-Whitney U-test as appropriate. Categorical variables were expressed as counts and percentages, and comparison of these variables was performed with Chi-square or Fisher＇s exact test. A two-tailed value of P 〈 0.05 was considered statistically significant for all comparisons. Statistical analyses were performed by SAS software （version 9.4, SAS Institute Inc., Cary, USA） for Windows. Results： In-hospital primary end point and the secondary end point were no significant differences between two groups （P = 1.000 and P = 1.000, respectively）. No significant differences between two groups were observed according to the long-term primary end point and the secondary end point. Kaplan-Meier survival curves showed no significant difference between the two groups in the primary end point and the secondary end point at 2 years （P- 0.340 and P = 0,243, respectively）. According to Cox analysis, female, intra-aortic balloon pump support, and postprocedural thrombolysis in myocardial infarction flow 3 were found to be independent predictors fbr long-term follow-up. Conclusion： Primary PCI with second-generation DES is a reasonable choice for STEMI patients caused by VLST.

Systematic Synthesis on Pathological Models of CCCII and Modified CCCII

According to the equivalent view for the terminal current-voltage constraint relationship between pathological elements and the various second-generation current-controlled convegors （CCCIIs）, four patholo- gical models for the CCCII are first derived by means of the nodal admittance matrix expansion in this paper. Moreover, 48 new pathological models for the modified CCCII are also synthesized. The derived pathological models for the various CCCIIs are expected to be useful in circuit analysis and synthesis.

聚苯胺修饰不锈钢电极防腐性能的研究

采用循环伏安法,通过在312型不锈钢电极上电化学聚合苯胺制备修饰不锈钢电极,并应用极化曲线、腐蚀电位时效分析以及交流阻抗对所得电极进行防腐性能的探讨.结果表明,与未修饰不锈钢电极相比,修饰后的不锈钢电极的腐蚀电位上升了160mV,腐蚀电流降低了20倍.腐蚀电位的时效分析证实,聚苯胺膜修饰的不锈钢电极可以在3%NaCl溶液中保持13 000min而不被腐蚀.通过等效电路拟合交流阻抗谱得到了不锈钢电极上的聚苯胺膜的电化学参数,并分析和探讨了聚苯胺修饰不锈钢电极耐蚀机理和失效机理.

氯化银比浊法测定水样中氯离子

目的建立氯化银比浊法测定水样中氯离子的方法。方法用硝酸调节溶液pH,加入硝酸银溶液,使之与氯离子反应,生成氯化银悬浊液,利用分光光度法测定吸光度,通过工作曲线确定浓度。结果氯离子浓度为0~6μg/mL时线性方程为Y=0.0473X-0.0004,相关系数为0.9995,线性关系较好,相对标准偏差为2.0%,回收率范围为96.89%~108.25%。结论此方法检测效率高,适合测定氯离子含量较小的样品。

De-Noising Stochastic Noise in FOG Based on Second-Generation DB4 Wavelet and SURE-Threshold

An effective de-noising method for fiber optic gyroscopes （FOGs） is proposed. This method is based on second-generation Daubechies D4 （DB4） wavelet transform （WT） and level-dependent threshold estimator called Stein＇s unbiased risk estimator （SURE）. The whole approach consists of three critical parts： wavelet decomposition module, parameters estimation module and SURE de-noising module. First, DB4 wavelet is selected as lifting base of the second-generation wavelet in the decomposition module. Second, in the parameters estimation module, maximum likelihood estimation （MLE） is used for stochastic noise parameters estimation. Third, combined with soft threshold de-noising technique, the SURE de-noising module is designed. For comparison, both the traditional universal threshold wavelet and the second-generation Harr wavelet method are also investigated. The experiment results show that the computation cost is 40% less than that of the traditional wavelet method. The standard deviation of de-noised FOG signal is 0.012 and the three noise terms such as angle random walk, bias instability and quantization noise are reduced to 0.007 2°/√h, 0.004 1° / h, and 0.008 1°, respectively.

Progress of the satellite laser ranging system TROS1000

The mobile satellite laser ranging system TROS1000, successfully developed in 2010, achieves a high repetition rate and enables daytime laser ranging. Its measurement range has reached up to 36000 km with an accuracy as precise as 1 cm. Using recent observations in Wuhan, Jiufeng, Xianning, and Rongcheng, Shandong, we introduce the progress made using this mobile observation system.