担载型镍催化剂上CH_4/CO_2重整反应的研究 Ⅱ.添加Co对Ni/Al_2O_3催化剂性能的影响

考察了ＣＯ助剂对Ｎｉ／Ａｌ２Ｏ３催化剂的活性和抗积炭性能的影响，发现添加少量Ｃo使催化剂 的抗积炭能力显著增强．ＴＰＲ、ＸＲＤ结果表明，Ｃo的添加降低了金属镍的分散度，并促进了尖晶石 ＮｉＡＩ２Ｏ４的生成．     

雾化喷射沉积成形中沉积体内的凝固过程（Ⅱ）——Al—Cu合金的计算

根据已知的喷射沉积成形沉积体内的凝固模型，地典型的Ａｌ－Ｃｕ合金进行了计算分析，结果表明，工艺参数和材料的热物性对沉积体内的凝固过程有明显影响，在沉积质力学条件（沉积前雾化锥的热力学状态）相同的情况下，沉积表面的温度随工艺参数和热物性发生显著变化。     

甚低频电磁波方法预报地磁暴

通过观察甚低频电磁波的相位变化,预测太阳耀斑的级别.当太阳耀斑爆发时,太阳表面首先会发出大量电磁辐射(主要是X射线),甚低频电磁波能很好地感应到此辐射;其次还喷射出大量带电低能粒子流,这会引起地磁暴,且通常在耀斑爆发1~2d之后到达地球.给出了一个预报地磁暴的实例.两事件的时间间隔约为28h,太阳风的速度约为1 484.1km/s.     

硅基SiC薄膜的制备及性能研究

文章采用电子束物理气相沉积法在单晶Si(100)基片上制备了单层SiC薄膜和Al2O3/SiC双层膜,然后在不同温度下经氩气保护退火。通过X射线衍射仪(XRD)、原子力显微镜(AFM)对所制备的薄膜进行了结构和表面形貌分析。研究表明:退火后SiC薄膜由非晶态转为晶态,随退火温度的升高,薄膜结晶更充分,薄膜表面平均粗糙度变小;双层膜与单层膜相比,其SiC衍射峰有所增强,薄膜表面更加平滑。     

Structure and magnetic properties of Ni50Mn35In15 thin film

Thin film of Ni50Mn35In15 Heusler alloy was prepared on Mg O(001) substrate by epitaxial growth in an ultra-high vacuum(UHV) chamber by a Pulsed Laser Deposition(PLD) method. The epitaxial growth process was monitored by in situ reflection high energy electron diffraction(RHEED) and the structure of the film was checked by ex situ X-ray diffraction(XRD), which indicates that high quality Ni50Mn35In15 single crystal film with a face-centered-cubic(fcc) structure could be stabilized on Mg O(001). Magnetic property measurement was also conducted at various temperatures by using physical property measurement system(PPMS). A significant exchange bias was observed for Ni50Mn35In15 film,and the strength of the exchange bias field(HEB) increases with the decrease of temperature. Such a behavior can be ascribed to the fact that the interfacial spin interaction between ferromagnetic(FM) and antiferromagnetic(AFM) cluster is enhanced with the decrease of temperature.     

Vertically aligned ZnO nanorods on porous silicon substrates: Effect of growth time

Vertically aligned ZnO nanorods were successfully grown on porous silicon(PS) substrates by chemical bath deposition at a low temperature.X-ray diffraction, field-emission scanning electron microscopy(FESEM), transmission electron microscopy(TEM), and photoluminescence(PL)analyses were carried out to investigate the effect of growth duration(2 h to 8 h) on the optical and structural properties of the aligned ZnO nanorods. Strong and sharp ZnO(0 0 2) peaks of the ZnO nanorods proved that the aligned ZnO nanorods were preferentially fabricated along the c-axis of the hexagonal wurtzite structure. FESEM images demonstrated that the Zn O nanorod arrays were well aligned along the c-axis and perpendicular to the PS substrates regardless of the growth duration. The TEM image showed that the top surfaces of the ZnO nanorods were round with a smooth curvature. PL spectra demonstrated that the ZnO nanorods grown for 5 h exhibited the sharpest and most intense PL peaks within the ultraviolet range among all samples.     

镁合金基HA材料生物相容性及生物活性的研究

采用电泳沉积法制备了镁合金基羟基磷灰石表面涂层生物复合材料.利用动物体内埋植实验和SBF浸泡实验分别对复合材料生物相容性及生物活性进行研究.将SD大鼠分为对照组和植入组,植入一定的时间后,取植入物周围组织进行切片、HE染色和组织分析;将复合材料恒温浸泡于SBF溶液四周后取出,通过检测复合材料表面生长磷灰石的能力作为评价该材料的生物活性.实验结果是植入物周围出现组织增生,有结缔组织及新生血管的形成,未见明显的组织炎症反应,无多核的巨细胞、淋巴细胞和中性粒细胞等炎细胞的浸润;复合材料浸泡于SBF溶液后,复合材料表面形成一层类骨磷灰石.表明镁合金基羟基磷灰石生物复合材料无细胞毒性,不引起机体免疫反应,能诱导磷灰石的形成,具有良好的生物相容性及生物活性.     

山西宁武-静乐盆地侏罗系砂岩碎屑组分及物源分析

通过沉积相特征识别、砂体宏观特征观察、古流向分析、砂岩镜下骨架颗粒统计,并结合沉积速率法、镜质组反射率法、Dickinson图解等方法探讨宁武—静乐盆地物源区的位置、母岩组合及其构造背景。研究结果表明:宁武—静乐盆地侏罗系砂岩类型主要为石英砂岩、长石砂岩和岩屑长石砂岩;砂岩骨架颗粒类型及其量比关系表明其物源区主要为大面积的花岗质侵入岩(细粒花岗岩、闪长花岗岩等)广泛出露,并有一定量的变质岩(云母片岩、千枚岩、石英岩等)和沉积岩(砂岩、富含燧石结核或条带的碳酸盐)分布;砂体中古流向数据均值介于158°~204°,反映了物源区是位于该盆地以北的阴山—燕山一带;Dickinson三角图解结果表明物源区总体上处于华北板块北缘陆内隆升的构造背景,且中侏罗世晚期可能伴随有火山作用;天池河组地层原始沉积厚度为269.4~308.0 m,155 Ma左右,区域地层抬升遭受剥蚀,其剥蚀厚度为148.1~207.0 m,剥蚀速率为1.8~2.1 m/Ma,结合镜质组反射率法,侏罗系地层最大埋深时该地区古地温梯度明显偏高,反映了宁武—静乐一带受到燕山运动构造热事件的显著影响。     

氮添加对亚热带常绿阔叶林土壤有机碳及土壤呼吸的影响

以福建省武夷山亚热带常绿阔叶米槠林为研究对象, 开展氮添加实验。采用4个氮添加梯度(CK, N50, N100和N150, 分别表示氮添加0, 50, 100和150 kg/(hm²·a))模拟自然氮沉降变化, 探究氮添加对土壤有机碳及土壤呼吸的影响。结果表明, 氮添加对表层土壤(0~20 cm)总有机碳的影响不显著, 对颗粒态有机碳(POC)和矿物结合态有机碳(MAOC)两种不同碳组分含量的影响不同。其中, N100和N150处理分别使土壤POC含量显著上升110.7%和147.9% (p₁ = 0.024, p₂ < 0.001); 土壤MAOC含量则随氮添加量升高呈下降趋势, 但差异不显著。土壤呼吸速率的年际波动呈单峰式, 且在不同观测时间内, 各样地土壤呼吸速率对氮添加的响应不同。通过土壤呼吸速率与土壤温度的拟合方程计算, 得到2018—2020年CK, N50, N100和N150样地土壤呼吸年均碳排放量分别为1205.31, 1191.56, 1287.56和1128.61 g C/m²。其中, N50样地与CK样地无显著差异, N100样地显著上升6.82% (p<0.001), N150显著下降 6.8% (p<0.001), 即N100可以促进土壤呼吸年碳排放, 而N150对土壤呼吸年碳排放有抑制作用。     

La0.67Sr0.33MnO3/PbZr0.4Ti0.6O3/La0.67Sr0.33MnO3外延铁电电容器物理性能

采用脉冲激光沉积法制备La_0.67Sr_0.33MnO₃(LSMO)薄膜,溶胶-凝胶法制备PbZr_0.4Ti_0.6O₃(PZT)薄膜,在SrTiO₃(STO)基片上制备了LSMO/PZT/LSMO异质结电容器.X线衍射(XRD)研究表明LSMO和PZT薄膜在STO基片上实现了外延生长.LSMO/PZT/LSMO电容器具有良好的铁电性能,在5 V测试电压下,剩余极化强度为26.9 μC/cm²,矫顽电压为2.5 V,LSMO/PZT/LSMO电容器显示出了良好的抗疲劳性能.5 V电压下电容器的漏电流密度为7.4×10^-6 A/cm²,在0~2.9 V为欧姆导电机制,2.9~5 V满足空间电荷限制电流(SCLC)导电机制.