At present, selective laser melting (SLM) 3D printing technology can accurately control the internal pore structure and complex cell shape. Three types of reticulated meshes with cubic, G7 and composite structure cell shapes were fabricated by the SLM 3D printing technology using Ti-6Al-4V alloy powders. The bone stresses around the implant and the stresses in the implant were analyzed by ANSYS finite element software, which comprehensively evaluated the effect of porous dental implants with different spatial porosity characteristics on osseointegration. The results show that porous dental implants with composite structure of pore characteristics have improved mechanical and biological properties and can better promote the growth and integration of bone tissue.

The optimized manufacturing route of selective laser melting (SLM) for Ti6Al4V alloy was simulated by Simufact Additive software through orthogonal experiment. The results show that laser power 200 W, scanning speed 1200 mm/s, spot diameter 0.1 mm and powder thickness 0.03 mm are the optimal processing parameters. Samples with different pore structures were fabricated by SLM according to the optimized parameters, and scanning electron microscopy images show that the porous structures processed by this process have better fidelity. The compressive strength and elastic modulus of solid and different pore structures were compared and analyzed through compression experiments. It is concluded that the composite structure as the structural model of the implant can better meet the requirement for mechanical properties of the implant.

江汉盆地是我国典型的内陆盐湖盆地,位于其中部的潜江凹陷发育盐间细粒沉积,近期油气勘探取得突破.为研究其沉积特征及其对页岩合油性的控制,本文基于岩心和多种测试方法将盐间细粒沉积划分出8种岩相,分别是舍灰泥质云岩、云质混合细粒岩、泥质混合细粒岩、灰质混合细粒岩、灰质泥岩/泥岩、云质泥岩、硫酸盐质混合细粒岩和云质/泥质钙芒硝岩.岩相组合有A和B两种:A类岩相组合为含灰泥质云岩、云质混合细粒岩和泥质混合细粒岩,夹少量灰质混合细粒岩、云质泥岩、硫酸盐质混合细粒岩和云质/泥质钙芒硝岩;B类岩相组合为云质泥岩、硫酸盐质混合细粒岩、云质/泥质钙芒硝岩,夹少量灰质泥岩/泥岩和泥质混合细粒岩.A类岩相组合富集碳酸盐质矿物且有机质含量高,岩心上表现为灰黑色泥质岩(泥质混合细粒岩和灰质混合细粒岩)与黄褐色云质岩(含灰泥质云岩和云质混合细粒岩)频繁更替,其中夹有白色硫酸盐质岩,呈透镜体状或层状产出,说明当时环境的盐度较低,镜下纹层大部分呈较为连续的微波状或水平状.其沉积特征反映了A类岩相组合的形成环境为还原性较好、盐度较低的深水区.B类岩相组合硫酸盐矿物含量和有机质含量较低,岩心上表现为白色高硫酸盐质岩夹有黑色泥质层或黄褐色云质层,镜下观察为呈菱形片状钙芒硝,常见穿插双晶,可见明显的粒序变化,云质含量高的薄片镜下为无纹层特征.其沉积特征反映了B类岩相组合形成环境为还原性较弱、盐度较高的较浅水域.本研究将V/(V+Ni)、(S1+S2)/TOC、Sr/Ba和Ga/C31H指数等地化参数与岩相特征相结合,进一步佐证了上述观点,并且补充说明了A类岩相组合形成于气候湿润的环境,而B类岩相组合形成环境较为干旱,且将盐间沉积划分为B、A、B三个阶段,对其进行了沉积模式的研究.结果 表明:第一、三阶段气候干旱且水深较浅,湖水析出大量盐类,主要发育B类岩相组合,且硫酸盐矿物的增加使硫酸盐还原菌氧化有机质,不利于有机质富集;第二阶段降雨增加,大量淡水注入致使水体淡化且深度变深,这时水体分层性较好,还原性较强,发育A类岩相组合,有机质的保存条件好.由此可见,矿物组分上为灰泥质或云质含量高且岩心具有水平层理、镜下纹层特征明显的岩相,以及湿润气候下的还原性较强、盐度适宜且水体分层性好的深水环境等沉积特征,有助于形成含油性较好的页岩.因此,低TOC含量的B类岩相组合不是油气富集的主要岩相,富集的硫酸盐矿物会稀释有机质浓度,岩相所处的高盐度环境也会减缓微生物活动;而高TOC含量的A类岩相组合为油气富集的主要岩相,频繁的降雨稀释水体盐度,为可以产生有机质的浮游微生物创造了良好的环境,且所含云质纹层矿物间孔隙发育,有利于烃类的存储,所以成为该区内的优质烃源岩,是油气勘探开发的有利岩相.

潜江凹陷位于江汉盆地,其古近系潜江组以含有由富有机质白云岩和蒸发岩组成的193个韵律层为特征.然而,潜江凹陷古近系潜江组白云石的成因一直存在争议,限制了进一步对非常规油气的勘探工作.根据盐间层岩相与矿物特征研究潜江组盐间层富白云石岩相的沉积成因.根据沉积特征观测(岩心和薄片)和矿物组分数据,可识别出3种主要的岩相结合:薄层-纹层状泥晶白云岩、纹层状含云泥晶灰岩和夹钙芒硝层状泥晶白云岩.研究发现前两种岩相组合纹层特征明显,可见有机质纹层与无机纹层交互现象,说明形成于水体较深的还原环境.白云石与方解石晶体含有有机质降解孔,且白云石与黄铁矿和有机质薄膜共生,说明其成因与微生物诱导活动有关.浮游微生物和底栖藻分别控制了方解石和白云石的沉淀.这些岩相组合含有较高的有机质含量.最后一种岩相组合具有较高的蒸发矿物含量和陆源碎屑物质,说明其形成于相对浅水环境.高盐度和强烈陆源输入不利于有机质的保存.此次研究发现盐湖内白云石的形成受微生物活动和蒸发环境控制,不同的成因对岩相沉积特征和有机质富集产生重要影响.