摘要：A polymeric hydroxyl ferric phosphate(PHFP)was prepared by using a byproduct of titanium dioxide containing ferrous sulfate and phosphates under alkaline *** PHFP was used to immobilize lead(Pb)and cadmium(Cd)in *** transform infrared spectra,X-ray diffraction were applied to revealing the characteristics of PHFP,and the modified Tessier sequential extraction and column leaching experiment with simulated acid rain were used to assess the effectiveness of immobilization of Cd and Pb in soils by *** results showed that PHFP was indeed a polymer with complicated OH-Fe-P structure and consisted of Fe6(OH)5(H2O)4(PO4)4(H2O)2and Fe25(PO4)14(OH)***,the removal rates of DTPA-extractable Cd and Pb in soils reached up to33%and45%,and the water-soluble Cd and Pb decreased by56%and58%,respectively,when PHFP was added in soils at4%*** addition,the immobilization of Cd and Pb contributed to transforming water soluble,exchangeable and carbonate-bonded fractions to Fe and Mn oxides-bonded,organic-bonded and residual *** leaching with simulated acid rain,Cd and Pb release amount in PHFP amended soil declined by53%and52%,respectively,as compared with non-treated *** result implied that PHFP had a potential application for the remediation of Cd-and Pb-contaminated soils.

摘要：海洋脐带缆通常由不同的功能构件捆绑而成,而这些功能构件的力学性能差异很大,在外载荷的作用下,不合理的截面布局可能会导致较大的截面变形和构件间的接触压力,从而影响脐带缆服役寿命。本文首先利用最小化截面半径给出截面布局紧凑性的实现方法,通过基于截面构件的拉伸刚度引入虚拟重力指标来描述截面布局的对称性,同时提出可量化的指标描述易损构件钢管之间的疲劳磨损问题。然后考虑上述三个目标建立截面布局多目标优化模型,并引入遗传算法对上述模型进行求解优化,自动得到三种具有代表性的截面优化布局。最后,通过数值模拟对不同截面优化布局进行验证与分析评价,进而得到最优截面布局设计。本文所提出的脐带缆截面布局设计优化方法可提高全局最优解搜索能力,对脐带缆结构设计具有一定的指导意义。

摘要：A process was proposed for removing and stabilizing arsenic(As) from anode slime. The anode slime with high arsenic concentration was pretreated by circular alkaline leaching process. Then, the arsenic in the leaching solution can be further precipitated as a form of scorodite crystalline(FeAsO4·2H2O). In the precipitating arsenic reaction, in which ferrous ions were oxidized by air gas, the effects of acidity(p H), reaction temperature, air flow rate, initial concentration of arsenic and initial molar ratio of Fe(II) to As(V) on arsenic precipitation were investigated. The results showed that sufficiently stable crystal scorodite could be achieved under the condition of initial arsenic concentration of 10 g/L, pH 3.0-4.0, Fe/As molar ratio of 1.5, the temperature of 80-95 °C, and the air flow rate higher than 120 L/h. Under the optimal condition, more than 78% of arsenic could be precipitated as a form of scorodite crystalline. The As leaching concentration of the precipitates was less than 2.0 mg/L and the precipitates may be considered to be safe for disposal.

摘要：锂硫电池因理论能量密度高、生产成本低和环境友好等优点被认为是最有前途的下一代电化学储能装置之一。然而,硫和硫化锂的低导电性、严重的穿梭效应和缓慢的反应动力学等问题阻碍了锂硫电池的大规模商业化应用。炭材料因高比表面积,良好导电性与结构多样性而备受关注,然而非极性炭材料难以与极性多硫化物紧密结合,导致活性材料大量损失和严重的穿梭效应。金属氧化物具有极性强和丰富吸附位点的优点,将过渡金属氧化物与炭材料结合,有助于增强对多硫化物的化学吸附和电化学反应活性。本文首先介绍了锂硫电池的基本原理和存在的主要问题,然后讨论了近年来过渡金属氧化物/炭复合材料在合成方法和结构设计(1D,2D,3D)方面的研究进展。此外,详细介绍了异质结构设计、空位工程和晶面调控策略的代表性工作并讨论了其机理。最后,对过渡金属氧化物/炭复合材料用于锂硫电池中的发展进行了总结和展望。

摘要：针对空间天文、生物荧光、光谱测量等领域对高灵敏、大面阵探测器的应用需求,研制出基于感应读出方式的延迟线阳极光子计数成像探测器。该探测器由微通道板、延时线阳极以及读出电路组成,其中延时线阳极的性能直接影响探测器的成像质量。作为一种电荷感应读出延时线阳极,该阳极利用信号到达的时间差解码入射光子的位置,可获得高的探测灵敏度和大的成像面积,同时简化了工艺难度并提升了可靠性。设计了感应读出延时线阳极,理论分析了探测器不同设计参数及材料对感应电荷量的影响,提出了解决异层电极间感应电荷量难以平衡的方法。据此研制出了收集面积为40 mm×40 mm的位敏阳极。测试结果表明该阳极信号传输衰减小于10%,极间串扰小于3%。利用该阳极进行了光子计数成像实验,获得了优于150μm的空间分辨率,为研制可应用于天文紫外光谱测量的大面阵、高灵敏探测器提供了理论依据及实验指导。

摘要：The traditional zinc hydro-metallurgy generates a large amount of zinc ferrite residue rich in valuable metals. The separation of iron is crucial for resource recycling of valuable metals in zinc ferrite residue. A novel selective reduction roasting？leaching process was proposed to separate zinc and iron from zinc leaching residue which contains zinc ferrite. The thermodynamic analysis was employed to determine the predominant range of Fe3O4 and ZnO during reduction roasting process of zinc ferrite. Based on the result of thermodynamic calculation, we found thatV（CO）/V（CO＋CO2） ratio is a key factor determining the phase composition in the reduction roasting product of zinc ferrite. In the range ofV（CO）/V（CO＋CO2） ratio between 2.68% and 36.18%, zinc ferrite is preferentially decomposed into Fe3O4 and ZnO. Based on thermogravimetric （TG） analysis, the optimal conditions for reduction roasting of zinc ferrite are determined as follows： temperature 700？750 °C, volume fraction of CO 6% and V（CO）/V（CO＋CO2） ratio 30%. Based on the above results, zinc leaching residue rich in zinc ferrite was roasted and the roasted product was leached by acid solution. It is found that zinc extraction rate in zinc leaching residue reaches up to 70% and iron extraction rate is only 18.4%. The result indicates that zinc and iron can be effectively separated from zinc leaching residue.

摘要：内涝风险较高是多数城镇面临的问题。以某感潮城镇片区为例,基于InfoWorks ICM建立的雨水管网-河段一二维耦合模型计算结果,利用地理信息系统(GIS)的栅格分析和邻域分析技术对孕灾环境危险性和易损性指标进行量化,最后运用GIS空间连接功能进行图层叠加。采用耦合熵权法和层次分析法计算各指标的组合权重,积水深度、积水流速、与幼儿园的距离、与医院的距离、GDP密度和人口密度的权重分别为0.365、0.177、0.084、0.088、0.084、0.202。构建基于主客观组合权重-TOPSIS-k-means++的内涝风险评估模型,并与主客观组合权重-加权评分-k-means++方法对比,验证了该方法的有效性。研究结果表明,综合考虑危险性和易损性指标,运用k-means++方法对风险等级进行聚类分析可为片区雨水管渠设计和内涝点整治提供综合性科学依据。

摘要：一种主要成分是脂质的白色不透明物质(WOS)会覆盖与癌症诊断有关的微观结构,但WOS的形态特征又与肿瘤分级有密切关系。为了给医生提供更多与脂质相关的可用信息,本文对脂质图像的分割方法进行了研究。首先,介绍了基于Retinex框架的脂质图像增强算法,并介绍了反光去除算法。然后,介绍了基于活动轮廓模型的脂质分割方法,该方法从校正后的色调值中提取局部信息,从强度值中提取全局信息,自适应地获得权重因子,并基于初始轮廓来分割脂质区域。最后,基于自研细胞内镜成像系统,设计了仿体实验来验证了该方法的有效性。实验结果表明,该分割方法的像素准确度、灵敏度、Dice系数均高于90%。该方法能够克服照明不均匀、反光等的影响,很好地反映脂质的形状,为医生提供可用的信息。

摘要：色氨酸羟化酶(TPH)可催化色氨酸羟化为5-羟基色氨酸(5-HTP),是5-HTP生物合成过程中的关键酶。为了提高大肠埃希菌细胞工厂合成5-HTP的效率,通过酶的理性设计和定点突变技术构建了人色氨酸羟化酶2(TPH2)的系列突变体,并在高产L-色氨酸且含有TPH辅酶四氢生物蝶呤(BH_(4))合成与再生模块的大肠埃希菌中表达。发现适当降低酶和色氨酸、酶和BH_(4)间结合的氢键数目有助于提高5-HTP产量;酶和底物色氨酸结合情况不变,辅酶BH_(4)与酶间氢键数目越多,5-HTP产量越低。5-HTP产量最高的细胞工厂是由突变酶V195A/V197I构建的,5-HTP产量较野生酶构建的细胞工厂产量提高54%,1 L补料摇床发酵48 h,5-HTP产量达16.17 g/L。理性设计是提高TPH2酶活,突破5-HTP合成限速步骤的有效途径,TPH2和底物色氨酸、辅酶BH_(4)间氢键连接太多或太少都不利于其催化活性的发挥。

摘要：面向基础科学与空间应用研究领域对小型化超快脉冲X射线发射源的需求,设计并研制了基于激光调制光源与光电阴极X射线管的超快脉冲X射线发生器,解决了传统X射线调制发射装置重复频率低、时间稳定性差、脉冲特性差等应用难题.本文主要开展了脉冲X射线发生器的超快调制控制模块研究,并利用基于预调制的激光控制光源实现了高时间精度、高时间稳定度的超快时变光子信号以及纳秒脉冲X射线产生.理论方面,建立了脉冲X射线发生器时间响应模型,分析了出射脉冲X射线的时域时间特性.实验方面,搭建了基于超快闪烁体探测器的脉冲X射线时间特性实验测试系统,测试了激光控制光源及脉冲X射线发射源的时间特性参数.实验结果表明脉冲X射线发生器可同时实现高重频(12.5 MHz)、超快脉冲(4 ns)、高时间稳定度(400 ps)特性,且与所建立的理论模型高度符合.相比于传统X射线调制方案,脉冲时间参数指标得到了大幅提升、应用场景获得了极大拓展,本项研究有望为实现超高时间稳定性、超快脉冲X射线发射源提供新思路.