Liver‐Specific and Echogenic Hyaluronic Acid Nanoparticles Facilitating Liver Cancer Discrimination

With the increasing demand for instant real‐time ultrasound (US) imaging of a specific organ, target‐specific and long‐circulating ultrasound contrast agents are of special interest. A new species of echogenic hyaluronic acid nanoparticles is presented as an ultralong‐acting, liver‐specific, US contrast agent that is distinct from conventional gas‐filled microbubbles. Using an oil‐in‐water (O/W) emulsification method, bioinert and hydrophobic perfluoropentane (PFP) is encapsulated as an ultrasound gas precursor into hyaluronic acid nanoparticles (HANPs) using hydrophobic interactions. HANPs are formulated by self‐assembly, with amphiphilic hyaluronic acid‐5β‐cholanic acid (HA‐CA) conjugating in aqueous conditions. The resulting echogenic PFP‐encapsulated HANPs (Echo‐NPs) show solid nanostructures, differentiated from core‐empty conventional microbubbles, and exhibiting outstanding physical properties as an ultrasound contrast agent. They are more stable and robust echogenic solid bodies with an in vivo favorable hydrodynamic size and because PFPs vaporize gradually, their expansion process is very slow in body conditions. After several systemic circulations, echo‐NPs generated intense and ultralong echo signals for US imaging at the target site. The echogenic properties of Echo‐NPs show a significantly increased half‐life and echo persistence, compared with conventional microbubbles. The results clearly show that echo‐NPs outperform conventional microbubbles in terms of both physical and echogenic in vitro and in vivo properties.     

乌尔逊凹陷北部圈闭综合评价

应用人工神经网络方法和灰色系统关联分析方法对乌尔逊凹陷北部构造圈闭进行了评价。神经网络方法的优势在于能从复杂的圈闭含油气性与相关地质因素之间的关系中建立非线性预测网络,而不必考虑地质经验和模式;灰色关联分析则在地质经验的基础上,通过圈闭评价标准的建立,对圈闭进行描述和比较,进而确定圈闭评价级别。评价结果表明乌尔逊凹陷北部具有良好的含油气远景,黄旗庙构造带、苏仁诺尔构造带,以及乌中断裂附近各圈闭应该是勘探中的重点。研究结果显示,在油气田勘探的特定阶段,综合应用这两种方法评价圈闭是科学合理的。     

氮气弹簧密封可靠性设计要点及结构

为了保证氮气缸弹簧的使用寿命,对氮气缸设计的关键技术问题进行了阐述,提出了高压氮气缸的密封可靠性设计要点及适用于氮气弹簧的动态密封结构形式。     

蜂窝式通风器中油滴运动与分离效率计算

为研究转速、空气流量、蜂窝孔长度、对边距及空气温度对蜂窝式轴心通风器油气分离性能的影响,建立了基于质点运动学的蜂窝孔内滑油颗粒运动方程,采用龙格-库塔法求解得到颗粒运动轨迹,结合蜂窝结构几何特点给出颗粒分离判据,在给定颗粒直径分布的条件下求得蜂窝孔的分离效率,分析了各项参数对蜂窝孔分离效率的影响,并给出了分离效率与各参数之间拟合关系式。结果表明：孔长和对边距一定时,分离效率随着转速提高和通风流量减小而增加;转速和流量一定时,增大蜂窝孔长度和减小对边距均使分离效率提高;降低空气温度使分离效率提高,但影响微弱。     

焦点移动现象的规律及成因

指出高斯光束人射时国孔衍射场的一般规律．画了不同Nw时衍射场振幅随（H,Pm）变化的函数图形。找到振幅极大值点移动的原因及焦移量的计算公式．     

MEMS环形陀螺模态间刚度耦合频率调谐

MEMS陀螺结构的驱动和检测模态谐振频率差(Δf)是决定其机械灵敏度的主要因素,当Δf≈0时,陀螺处于频率调谐状态,此时陀螺的机械灵敏度达到最大值。本文针对一种电容式全对称S形弹性梁硅基环形波动陀螺,对其使用调频电压进行频率调谐过程中发现,模态间存在一定的刚度耦合。本文分析其模态间刚度耦合产生的原因是结构误差(环形谐振子的结构误差主要体现在两个振动参数,一个是频率,另一个是阻尼),由于调频电压改变的主要参数是刚度系数,所以本文仅对频率误差进行建模分析。首先,介绍了环形陀螺结构,同时以此结构为基础分析了静电负刚度原理。其次,分析了其频率误差产生的原因,并建模推导出调频电压对两个工作模态产生的影响。最后,结合理论模型和实验结果比对,验证理论推导的正确性,并通过实验验证频率调谐状态下对环形陀螺的灵敏度提升了2.7倍。     

二维参数化CAD系统XD-2DEM的开发

本文论述二维参数化设计系统X D-2DEM的设计原则,较详细地讨论了系统中各模块的功能,并介绍该系统所需的软硬件环境。     

共析轨钢塑性应变与应变疲劳关系的研究

用全反向恒应变幅试验方法,研究了C-Mn轨钢珠光体及回火索氏体的应变疲劳行为,探讨了塑性应变在应变疲劳中的作用。试验结果表明,轨钢的疲劳是塑性应变控制过程。大应变幅时,疲劳寿命的急剧缩短与塑性应变幅的快速增长有关,减小片间距会降低塑性应变幅在总应变幅中所占比例;抗拉强度相等时,因循环软化而致的塑性应变幅增大及较小的可允许应变范围是回火索氏体疲劳寿命低于珠光体的主要原因。     

THE RELATIONSHIP BETWEEN CONTENT, VALENCE STATE OF Fe AND COLOUR IN XIUYAN JADE

Having beautiful colours and fine features, Xiuyan jade is famous in the world. Mineralogically, Xiuyan jade is serpentine jade. XRD, IR and TEM studies indicate that the jade consists mainly of antigorite (m{Mg3(1-1/m)[Si2O5](OH)1+3(1-2/m}) with a minor amount of chrysotile. Two favourite samples (PxA, Px1-1), chosen for research on Fe Mossbauer spectra, are only antigorite. Studies indicate that: a. iron ion in antigorite enters the lattice as impurity; b. Fe2+ and Fe3+ substitute for Mg in the coordination octahedron; and c. the colour of jade is related to content of Fe, and Fe2+/Fe3+≤1 is favourite for colour-forming.