2D Minimum Compliance Topology Optimization Based on a Region Partitioning Strategy

This paper presents an extended sequential element rejection and admission(SERA)topology optimizationmethod with a region partitioning strategy.Based on the partitioning of a design domain into solid regions and weak regions,the proposed optimizationmethod sequentially implements finite element analysis(FEA)in these regions.After standard FEA in the solid regions,the boundary displacement of the weak regions is constrained using the numerical solution of the solid regions as Dirichlet boundary conditions.This treatment can alleviate the negative effect of the material interpolation model of the topology optimization method in the weak regions,such as the condition number of the structural global stiffness matrix.For optimization,in which the forward problem requires nonlinear structural analysis,a linear solver can be applied in weak regions to avoid numerical singularities caused by the over-deformedmesh.To enhance the robustness of the proposedmethod,the nonmanifold point and island are identified and handled separately.The performance of the proposed method is verified by three 2D minimum compliance examples.

Heavy metals in sediments of Yellow Sea and East China Sea: Chemical speciation,distribution,influence factor,and contamination

Metal species and the degree of environmental pollution are related to the hydrogen sulfide(H_(2)S),an important product of early diagenesis that can react with metals to form stable compounds.To investigate the eff ects of H_(2)S to metals and evaluate metal environment eff ect in the sediments of the East China Sea(ECS)and Yellow Sea(YS),geochemical characteristic and spatial distribution of nine heavy metals and H_(2)S profile were studied.Higher H_(2)S content and lower metal content was observed in the sediments 10 cm in depth in the North Yellow Sea and the west coast of South Korea.The pollution load index(I_(pl))indicates that the southern coast of Shandong Peninsula underwent moderate pollution(I_(pl)=1)of heavy metals and no heavy metal pollution appeared in other areas(I_(pl)<1).To some extents,the ecological risk of Cd and As enrichment was moderately severe in all stations.The chance of heavy metal combination to be toxic in ECS and YS during summer was 21%.In addition,correlation between H_(2)S content and metals in both solid and porewater phases was obvious,corroborating important eff ect of H_(2)S on metal distribution.Moreover,H_(2)S could aff ect the spatial distributions of heavy metals in porewater directly and be indicative of potential biological eff ects of combined toxicant groups in the study region.

4.8 nm Concave {M_(72)}(M=Co,Ni,Fe) metal-organic polyhedra capped by 18 calixarenes

Three 4.8 nm isostructural{M_(72)}(M=Co^(Ⅱ) for CIAC-128,Ni^(Ⅱ) for CIAC-129,Fe^(Ⅱ) for CIAC-130) metal-organic polyhedra(MOPs) are constructed by eighteen M_(4)-p-tert-butylthiacalix[4]arene (M_(4)-TC4A) units bridged via sixteen four-connected 5,5′-(1H-1,2,4-triazole-3,5-diyl) diisophthalic acid (H_(4)TADIPA) linkers.These MOPs are featured with a rarely reported concave coordination cage,which can be simplified as a squeezed double-decker hexagonal prism pressed from the top and bottom hexagonal faces.Furthermore,CIAC-128,CIAC-129 and CIAC-130 are the highest nuclearity discrete clusters of Co,Ni and Fe reported so far.CIAC-128 has higher separation selectivity of C_(3)H_(8) than CH_(4) under ambient conditions,and also exhibits separation selectivity for C_(2)H_(6)/CH_(4),C_(2)H_(2)/CH_(4),and C_(2)H_(4)/CH_(4).In addition,CIAC-128 can provide the cavity for the confined synthesis of noble metal nanoclusters such as Pd nanoclusters and the resulting Pd@CIAC-128 hybrids show higher electrocatalytic activity than commercial Pt/C towards hydrogen evolution reaction (HER).

康柏西普治疗早产儿视网膜病变患儿屈光状态改变的临床研究

目的:观察玻璃体腔注射康柏西普(IVC)治疗早产儿视网膜病变(ROP)患儿后的屈光状态改变,探讨ROP患儿屈光状态与注药次数、孕周、出生体质量、眼轴、视网膜血管发育情况之间的相关性。方法:前瞻性临床研究。选取2017年4月至2021年6月就诊于潍坊眼科医院并诊断为“2型ROP阈值前病变”的患儿64例(127眼)。根据其病情严重程度按需行IVC治疗,以治疗次数分为注药0次(A组)共22例(43眼)、注药1次(B组)共30例(53眼)、注药2次(C组)共18例(31眼),在其矫正胎龄3、6、12个月时,观察屈光状态,记录等效球镜度(SE)、散光、眼轴、视网膜血管分区等情况。3组SE比较采用单因素方差分析,散光比较采用Kruskal-Wallis非参数检验,SE与孕周、出生体质量、眼轴及视网膜血管分区的关系采用Pearson及Spearman相关性分析。结果:矫正胎龄3个月和6个月时,3组SE及散光差异均无统计学意义;矫正胎龄12个月时,3组SE及散光差异均有统计学意义(F=6.59,P=0.002;H=7.39,P=0.025)。进一步两两比较,A组与B组、A组与C组之间SE差异有统计学意义(P=0.006;P=0.007),A组与C组散光差异有统计学意义(P=0.020)。矫正胎龄12个月时,3组屈光不正发生率、近视率差异无统计学意义,散光发生率差异有统计学意义(χ^(2)=8.96,P=0.011)。进一步两两比较,A组与C组、B组与C组差异有统计学意义(χ^(2)=7.08,P=0.008;χ^(2)=6.82,P=0.009)。矫正胎龄3个月时,SE与孕周(r=-0.18,P=0.043)、出生体质量(r=-0.19,P=0.032)、眼轴(r=-0.26,P=0.003)、视网膜血管分区(r=-0.20,P=0.023)均呈负相关;矫正胎龄6个月、12个月时,SE与眼轴呈负相关(r=-0.30,P=0.001)。结论:矫正胎龄12个月时,IVC治疗后ROP患儿远视储备低于自发消退的ROP患儿,重复注药对ROP患儿短期屈光状态无显著影响。