青楷槭不定根形成的解剖学研究

以青楷槭2 a生插条为材料,采用石蜡切片法对其不定根形成过程进行解剖学观察.结果表明:青楷槭茎的结构由表皮、皮层和次生维管组织组成;不定根生成方式属于诱导型,维管形成层和皮层的愈伤组织形成根原基;插条基部皮层的愈伤组织数量多,分布均匀,可形成不定根;切口部位愈伤组织不分化形成不定根.     

京津冀协同视角下区域大气污染现状及综合防治研究

京津冀区域大气污染已成为全国空气污染的重灾区,目前京津冀区域大气污染合作治理共识已基本形成。本文在对京津冀大气污染区域合作治理现状进行系统研究的基础上,以SO2、NO2、PM10、PM2.5四种污染物为指标,对京津冀目前大气质量状况以及15年来的大气质量变化趋势做了全面梳理分析。对存在的问题进行了探讨,并针对当前京津冀区域大气污染防治措施提出了建议,以期为破解区域大气污染治理困境提供借鉴参考。     

TTAC-HPMo/SiO_2催化剂的表征及其氧化脱硫性能分析

以十四烷基三甲基氯化铵(TTAC)为模板剂,正硅酸乙酯(TEOS)为硅源,采用溶胶-凝胶法制备TTAC-HPMo/SiO_2催化剂,利用FTIR、XRD、SEM和N_2吸附-脱附等技术对其进行表征,并分析催化剂制备条件和反应条件对模型油氧化脱硫性能的影响。结果表明,在m(HPMo)/m(SiO_2)=15%、焙烧温度为400℃条件下所制TTAC-HPMo/SiO_2催化剂,其孔隙结构发达、氧化脱硫性能最佳;对于10mL以二苯并噻吩(DBT)为目标含硫化合物的模型油(硫含量为400μg/g),当m(TTAC-HPMo/SiO_2)/m(模型油)=0.43%、V(H_2O_2)/V(模型油)=0.2%、反应温度为60℃、反应时间为14min时,所制TTAC-HPMo/SiO_2催化剂对模型油中DBT的脱除率达到100%。     

Nanoindentation response analysis of TiN-Cu coating deposited by magnetron sputtering

To investigate the change of the mechanical properties of soft metals doped PVD(Physical Vapor Deposition)coatings after the migration of soft metal to the surface, TiN-Cu coating was deposited on Si(100) by magnetron sputtering. The microstructure and mechanical properties at room temperature and after vacuum heat treatment at 300 ℃ were investigated. The results showed that the grains were clustered and the microstructure was porous for TiN-Cu coating at room temperature, while many micro-and nano-sized Cu particles were observed on the surface after vacuum heat treatment at 300 ℃. The elastic properties of the TiN-Cu coating after vacuum heat treatment at 300℃ degraded compared with that at room temperature. The hardness and elasticity modulus of TiN-Cu coating kept constant(3.7 GPa and 125.0 GPa, respectively) with the increase of nano-indentation depth, while the hardness and elasticity modulus of TiN-Cu coating after vacuum heat treatment at 300 ℃ increased gradually.     

Study on the hydrogen storage property of (TiZr0.1)xCr1.7-yFeyMn0.3 (1.05

Jigang Li  Li Xu  Xiaojing Jiang  Xingguo Li 《自然科学进展(英文版)》2018,28(4):470-477

Novel multiferroicity in orthorhombic SmCrO3

This paper reports the ferroelectricity in antiferromagnetic SmCrO_3 with a reasonably large value of spontaneous electric polarization(70μC/cm~2mC cm~(-2)at 50 K)based on the measurement of pyroelectric current.The experimental results showed that the temperature of the onset of polar order was evidently higher(about220 K)than the Neel temperature(T_N=197 K)in the magnetodielectric studies.The calculated magnetodielectric effect(MDE)value was explicitly negative with maximum|MDE|values of about 3.6%around 230 K.The absence of a convincing signature in MDE at antiferromagnetic ordering temperature T_Nindicated the absence of magnetoelectric coupling around this temperature regime.The results further confirmed that the onset of polar order can be attributed to the structural distortion,rather than the canted noncollinear magnetic structure.     

氮素形态配比对镉污染下小白菜生长及碳氮积累的影响

以小白菜为材料,设置4个镉(Cd)浓度水平以及3个氮素形态配比,分析镉-氮相互作用对小白菜生长及碳氮代谢相关指标的影响,结果表明:Cd的物质的量浓度为5μmol·L~(-1)时,对小白菜地上部分鲜重、总氮含量影响不显著;当Cd的物质的量浓度为50、100μmol·L~(-1)时,小白菜鲜重和总氮含量显著降低.无论是否添加Cd,硝铵比3/7处理的小白菜鲜重显著低于硝铵比10/0(全硝)和硝铵比7/3处理;100μmol L~(-1)Cd处理时小白菜地上硝酸盐的含量显著低于对照组,其余处理与对照差异不显著;不同Cd浓度处理均降低了小白菜的游离氨基酸含量,提高了其可溶性蛋白质含量.相对于全硝处理,以硝铵比7/3为氮源可提高50μmol·L~(-1)Cd处理时小白菜的总氮含量、游离氨基酸含量及100μmol·L~(-1)Cd处理的小白菜地上部分硝态氮含量.当以全硝及硝铵比7/3为氮源时,小白菜地上部分总碳含量随Cd浓度的增加而增加,而可溶性糖含量仅在100μmol·L~(-1)Cd处理时显著高于无镉对照组.小白菜地上部分总Cd含量随Cd处理浓度的增加而增加,但在全硝和硝铵比7/3处理间差异不显著.综上,不同硝铵比影响镉胁迫下小白菜的生长和碳氮积累,适宜硝铵配比有助于提高小白菜对镉的耐受性.     

何作霖先生最早发现莱芜铁矿是接触变质矿床——读《山东博山莱芜间地质矿产》有感

1949年8月,何作霖受山东省政府工矿部的邀请,在博山莱芜间进行地质调查,查明莱芜有三处铁矿。尤其是莱芜矿山地区的接触变质磁铁矿的发现,为以后寻找和勘探莱芜铁矿提供了可靠线索及依据。同时何作霖还预测了莱芜与吐丝口间煤田的存在。     

Ground demonstration system based on in-orbit assembly oriented manipulator flexible force control

To eliminate the load weight limit of carrier rockets and reduce the burden on support struc-tures,in-orbit assembly is a key technology to make design of scattering a large diameter telescope into submirror modules, which requires smooth operation of assembly robots, and flexible force con-trol technology is necessary.A ground demonstration system is presented for in-orbit assembly focu-sing on flexible force control.A six-dimensional force/torque sensor and its data acquisition system are used to compensate for gravity.For translation and rotation, an algorithm for flexible control is proposed.A ground transportation demonstration verifies accuracy and smoothness of flexible force control, and the transportation and assembly task is completed automatically.The proposed system is suitable for the development of in-orbit assembly robots.     

基于数值积分与功率损耗测试的冷轧电机功率模型

为提高冷轧电机功率的计算精度,提出了一种新型的电机功率在线计算模型,模型中将电机功率分为轧制功率和机械功率损耗.其中,轧制功率采用基于简易有限元的数值积分方法计算获得,而电机机械功率损耗采用实验测试回归方法获得.基于本文设计的测试方案和模型结构,通过对某1 450 mm五机架冷连轧机组的现场测试,回归得到了功率损耗模型中的系数,并将其应用到了该机组中.现场实际应用表明该电机功率模型的计算偏差可控制在±5%以内,证明该模型具有较高的计算精度,符合现场控制要求,具有广泛的应用前景.