面向江豚生境需求的长江干流(铜陵段)生态流量过程研究

长江江豚是长江水生态系统健康的重要指示物种,满足其生境需求的生态流量过程是长江干流生态需水研究的关键。为科学明确保障长江江豚适宜生境的流量需求,采用水文改变指标法和变化范围法评价长江干流(铜陵段)水文情势变化。以水深、流速为限制因子,通过栖息地模拟法获得适宜江豚栖息的生态流量范围,耦合水文学法结果,推荐月尺度的生态流量方案;结合流量组分特征进行高流量脉冲设计,综合确定生态流量过程。结果表明:1)长江干流(铜陵段)水文情势改变度达49.74%,为中度改变,且流量事件主要以枯水流量和高流量脉冲为主,环境流量事件趋向单一化;2)长江江豚栖息地适宜流量范围为19000~31100 m^(3)/s,最佳适宜流量范围为22500~28500 m^(3)/s;丰水期适宜范围为27000~31000 m^(3)/s、35000~45000 m^(3)/s、60000~62000 m^(3)/s;高流量脉冲事件为流量值高于39100 m^(3)/s时,其持续时间至少在3 d以上,并以高流量脉冲峰值上限48000 m^(3)/s作为小洪水发生的初始值。本研究成果可为长江干流江豚生境保护和生态调度提供科学数据支撑,为切实推进长江大保护提供技术支撑。

Ni-Al-Cr原子间近邻作用势及沉淀过程的相场法模拟

基于微观相场理论研究了不同原子间近邻作用势(W)对Ni-Al-Cr合金析出过程和微观结构的影响。根据原子间近邻作用势与长程序参数方程的L10、L12和D022相的原子间近邻作用势公式,计算出Ni-Al-Cr合金的L10、L12和D022相的不同原子间近邻作用势。结果表明:随着温度的增长/减小,原子间近邻作用势近似呈线性增长/减小;随着溶质原子浓度的增长以及长程序参数的增大,原子间近邻作用势均呈上升趋势;Ni-Al、Ni-Cr、Cr-Al原子间近邻作用势的变化对L10、L12和D022析出相的沉淀形貌和体积分数的影响也各不相同:Ni-Al的第二近邻作用势的变化对于沉淀形貌和体积分数几乎无影响,而Ni-Cr第四近邻作用势的变化对沉淀形貌和体积分数的影响非常大。同时发现与其他方法相比,所得不同原子间近邻作用势结果近似,且沉淀形貌与实验结果吻合。

卤素水分仪测定推进剂燃烧催化剂水分的研究

通过卤素水分仪和烘箱法测定了推进剂燃烧催化剂的水分含量,研究了影响卤素水分仪测定推进剂燃烧催化剂水分含量的因素,并与传统烘箱法进行了对比。结果表明,干燥时间对卤素水分仪测定推进剂燃烧催化剂水分含量影响较小,样品质量、干燥温度、质量损失率是影响卤素水分仪测定推进剂燃烧催化剂水分的重要因素;卤素水分仪测试结果与烘箱法结果基本一致,测量结果重复性好,试验相对标准偏差小,极大的缩短了检测时间。

一类具ψ-Caputo导数的分数阶微分方程边值问题解的存在性

分数阶微分方程的研究可以解决数学、空气动力学、经济学、聚合物流变学等多个领域的复杂问题;在一类具ψ-Caputo导数的分数阶微分方程边值问题中,其中边值条件包含多点和积分,首先由ψ-Caputo导数的定义和性质获得解的等价积分方程形式,接着该边值问题解的唯一性与存在性分别由Banach压缩映像原理和Schauder不动点定理获得,最后,通过一个实例说明了结果的应用性。

Effect of Grain Boundary on Spinodal Decomposition Using the Phase Field Crystal Method

Spinodal decomposition (SD) with different grain boundaries (GBs) is investigated on the atomic scale using the novel phase field crystal model.It is demonstrated that the decomposition process is initiated by precipitating one phase with a larger lattice constant in the tension region at the GBs and the other one with a smaller lattice constant in the compression region.As the phase separation proceeds,the dislocations comprising the low-angle GBs migrate toward the compositional domain boundaries to relieve the coherent strain energy,and eventually become randomly distributed in the coarsening regime of SD,which leads to the disappearance of the low-angle GBs.For high-angle GBs,the location of GBs remains unchanged,while the atoms rearrange along the GBs to fit the stress field arising from compositional inhomogeneity.

智能化技术在电气工程自动化控制中的应用

随着人类社会科技水平不断提高,智能化技术的应用范围越来越广泛。对于电气工程自动化控制工作来说,使用智能化技术可以有效弥补电气工程自动化控制过程中传统方法所带来的不足,提高工作效率,同时相对地也面临着实际操作过程中的困难和挑战。文中对电气工程自动化控制中智能化技术的应用进行了分析,可以在更全面认识到智能化技术为电气工程自动化控制工作带来的巨大革新的同时,也认识到工作过程中面临的技术挑战等。

基于大型底栖动物完整性指数的河湖生态系统健康评价——以安徽铜陵为例

大型底栖动物是河湖水系生态健康的重要指示。2020年8月和11月在沿江城市铜陵市开展了典型河湖水系的大型底栖动物调查,构建了大型底栖生物完整性指数(Benthic Index of Biological Integrity,B-IBI),并进行了生态健康评估。根据铜陵市河湖生态系统43个底栖动物样点(8个参照点和35个受损点)数据,对46个候选参数进行了分布范围、判别能力和相关性分析,从中筛选出总分类单元数、腹足纲单元数、Margalef丰富度指数和撕食者单元数,构成大型底栖动物生物完整性指数的核心参数,采用比值法计算各指标的分值和评价标准。评价结果表明,铜陵河湖水系的B-IBI平均得分为1.47,整体处于亚健康状态。在43个采样点中9个处于健康状态,14个处于亚健康状态,5个处于一般状态,7个处于差状态,8个处于极差状态。研究可为沿江城市河湖水系生态健康评价和河湖管理提供科学依据。

Protection of human islets from induction of apoptosis and improved islet function with HO-1 gene transduction

Background Islet transplantation represents an ideal therapeutic approach for treatment of type 1 diabetes but islet function and regeneration may be influenced by necrosis or apoptosis induced by oxidative stress and other insults. Heme oxygenase-1 （HO-1） is the rate-limiting enzyme in the catabolism of heme into biliverdin, releasing free iron and carbon monoxide. It has also been reported to be an antioxidant enzyme which can improve the function of grafted islets by cytoprotection via free radical scavenging and apoptosis prevention. In the present study, we investigated whether transduction of HO-1 genes into human islets with an adenovirus vector has cytoprotective action on islets cultured in vitro and discuss this method of gene therapy for clinical islet transplantation. Methods Cadaveric pancreatic islets were isolated and purified in vitro. Transduction efficiency of islets was determined by infecting islets with adenovirus vector containing the enhanced green fluorescent protein gene （Ad-EGFP） at multiplicities of infection （MOI） of 2, 5, 10, or 20. Newly isolated islets were divided into three groups： EGFP group, islets transduced with Ad-EGFP using MOI=20; HO-1 group, transduced with adenovirus vectors containing the human HO-1 gene using MOI=20; and control group, mock transduced islets. Insulin release after glucose stimulation of the cell lines was determined by a radioimmunoassay kit and the stimulation index was calculated. Flow cytometry was used to detect apoptotic cells in the HO-1 group and in the control group after induction by recombinant human tumor necrosis factor-α （rTNFα） and cycloheximide （CHX） for 48 hours. Results Adenovirus vectors have a high efficiency of gene transduction into adult islet cells. Transduction of islets with the Ad-EGFP was most successful at MOI 20, at which MOI fluorescence was very intense on day 7 after transduction and EGFP was expressed in cultured islet cells for more than four weeks in vitro. The insulin release in the control group was （182.36 ± 58.96） mIU/L after stimulation by high glucose media （16.7 mmol/L）,while insulin release from the HO-1 group and the EGFP group were （270.09±89.37） mlU/L and （ 175.95 ± 75.05） mlU/L respectively. Compared to the control group and the EGFP group, insulin release in the HO-1 group increased significantly （P〈0.05）. After treatment with rTNFα and CHX the apoptotic ratio of islet cells was （63.09 ± 10.86）% in the HO-1 group, significantly lower than （90.86 ± 11.25）% in the control group （P〈0.05）. Conclusions Transduction of human islets with Ad-HO-1 can protect against TNF-α and CHX mediated cytotoxicity. The HO-1 gene also appears to facilitate insulin release from human islets. Transduction of donor islets with the adenovirus vector containing an HO-1 gene might have potential value in clinical islet transplantation.