空调系统多分散相颗粒悬浮扩散的数值模拟

为了研究多分散相颗粒在通风空调系统中悬浮扩散过程,采用CFD方法,根据力或力矩平衡原理,针对通风空调系统粘性底层中颗粒的悬浮运动进行了数值模拟;连续相采用Euler方法,离散相采用Lagarngian方法进行模拟;湍流流动采用标准k-ε模型进行求解.通风空调系统可悬浮颗粒在起始送风气流作用下分多次送入室内;相比较管道越长起始的送入量越少;在直管段上近端送风口的送出量大于远端送风口的送出量;在直管段上增加弯管后,送出量减少而沉降量增多.采用的数值模型合理,有效的捕捉了流场和颗粒运动规律.     

碳纳米管内包覆Fe/Co粒子的磁性能

采用自制的装置,通过阳极弧光放电法制备了内包覆Fe/Co磁性纳米粒子的碳纳米管(CNTs).利用透射电子显微镜(TEM)、拉曼散射光谱和X射线衍射(XRD)对其进行表征,用振动样品磁强计(VSM)检测得到其磁学性能参数.TEM测试表明,CNTs杂质少,管径均匀一致,CNTs内包覆的物质均匀、连续,且为Fe/Co粒子.磁学性质的测量表明, CNTs的磁学性能较包覆前有了很大的改善,其比饱和磁化强度ós为17.30A·m2·kg-1,比剩余磁化强度ór为3.96A·m2·kg-1,矫顽力Hc为31521.60A·m-1.     

可吸入颗粒污染物在下呼吸道运动和沉积规律的数值模拟

为研究受慢性阻塞性肺病影响的呼吸道内气固流动特性,建立了基于Weibel模型的5～8级三维肺部模型.气相采用标准k-ε湍流模型,颗粒相采用离散颗粒模型.三级呼吸道内模拟的气固流动特性与实验结果进行了对比验证.在呼吸强度为30,60和90 L/min条件下,模拟了稳态、非稳态吸气时第7级内侧呼吸道受慢性阻塞性肺病影响收缩...     

Receptor-rich intracellular membrane vesicles transporting asialotransferrin and insulin in liver

A wide range of receptors are located at the blood sinusoidal aspect of the hepatocyte plasma membrane. Many circulating ligands that bind to receptors on the cell surfaces are interiorized along two pathways. Asialoglycoproteins are transferred from the plasma membrane to lysosomes and degraded, whereas immunoglobulin A and bile acids are transported across the hepatocyte interior and released into bile. Asialotransferrin type 3 (ref. 6) follows a further pathway termed diacytosis. After binding to the asialoglycoprotein receptor, asialotransferrin is endocytosed and then returned to blood with a proportion of its carbohydrate side chains resialylated. We now describe in liver the properties of intracellular asialotransferrin-enclosing vesicles (diacytosomes) and show that they differ from Golgi, lysosome and plasma membrane fractions. Furthermore, we show that the asialoglycoprotein binding sites are located on the cytoplasmic (outer) surface of diacytosomes.     

磁性物体磁偶极子模型适用性的试验研究

磁偶极子模型是一种简单却有着广泛应用的磁性模型,尤其在磁性目标探测领域有着广泛的应用.针对磁偶极子模型的应用仅仅凭经验和对模型的应用原理没有清晰认识的情况,提出了利用试验研究得到模型应用条件的思路.在近场磁场测量的基础上,建立了通过考察等效磁矩收敛性和磁场相对误差得到磁偶极子模型适用条件的试验研究方法.在理论分析的基础上,对5种不同的磁性物体模型进行了试验研究.试验结果表明,在2.5倍物体长度以上的空间,磁性物体的等效磁矩收敛,并且磁场相对误差很小,可以把磁性物体视作磁偶极子处理,能够满足工程上的要求,为磁偶极子模型的合理应用提供了依据.     

Evidence for a charge-shift electrochromic mechanism in a probe of membrane potential.

Extrinsic optical probes have become important tools for monitoring membrane potential, with probes now available for many tissue or cell suspension systems. In each case that has been studied in detail, it seems that the mechanism involves a shift in the equilibrium population of the probe from one chemical environment to another in response to the transmembrane potential; the environments perturb the probe's spectrum differently. As this indirect mechanism involves a redistribution of dye between chemical environments that are likely to vary if a given probe is transferred from one membrane to another, a potential probe that is effective and calibrated for all membrane systems has not been realised. We present here evidence for a direct response of a probe chromophore to the electric field across membrane systems. The results suggest it might be possible to develop a universal set of membrane probes.     

磁性药物微球的药物释放规律及磁定向规律研究

磁性药物微球的组成直接影响其药物释放速度。当微球中固化白蛋白含量接近时,药物含量越高,微球的通透性越好;药物含量相同时,固化白蛋白含量越高,药物的通透性越差。磁性药物微球的水悬浮液通过外磁场时的定位量随着介质流速的减小、外磁场的增强和微球中Fe_3O_4含量的增加而增加。增加分散介质粘度时,微球的定位量减小。     

磁性药物微球的药物释放规律及磁定向规律研究

磁性药物微球的组成直接影响其药物释放速度。当微球中固化白蛋白含量近接时，药物含量越高，微球的能性越好；药物含量相同时，固化白蛋白含量越高，药物的通透性越差。磁性药物微球的水悬浮液通过外磁场时的定位量随着介质流速的减小，外磁场的增强和微球中Ｆｅ３Ｏ４含量的产加而增加。增加分散质度时，球的定位量减小。     

复印技术中磁辊磁场的仿真

本文论述用积分方程法计算复印机磁辊磁场的分布，引入了磁场耦合系数并考虑磁性材料的各向异性，从磁场基本方程出发推导了磁位的积分解式。计算结果与实测的磁场数值符合较好。本文方法可用于磁辊生产中控制加工、装配尺寸误差及材料磁性离散度等影响质量的因素。     

空间载流线圈的磁矩及其在均匀磁场中的磁力矩

文中导出了任意形状空间的载流线圈磁矩的计算公式及其在均匀磁场中所受磁力矩的计算公式，结果表明本文的结论与电磁不理论的有关知识是相全的。     

E&AMode:一种新的基于引擎粒子系统的图像渲染模式

本文分析了图像引擎粒子系统的传统实现方法的优劣,提出了一种称为发射源&影响者(E&AMode)的图像渲染模式,该模式实现了粒子系统模拟效果的多样性,粒子运动状态的动态性和结构设计的灵活性.本文介绍了新模式的基本结构、算法思想和实现方法.试验结果表明,发射源&影响者模式能够实现粒子属性的灵活设置,粒子运动状态的动态改变和模拟效果的多样性.     

有限长通电螺线管内部空间磁场的模拟

利用叠加原理 ,用计算机模拟计算出有限长通电螺线管内部空间的磁场分布 .结果表明 ,除了螺线管两端之外 ,其内部为非常好的均匀磁场分布 .通过与实验测量结果的比较 ,说明该模拟方法是正确的     

Controlled surface charging as a depth-profiling probe for mesoscopic layers

Probing the structure of material layers just a few nanometres thick requires analytical techniques with high depth sensitivity. X-ray photoelectron spectroscopy (XPS) provides one such method, but obtaining vertically resolved structural information from the raw data is not straightforward. There are several XPS depth-profiling methods, including ion etching, angle-resolved XPS (ref. 2) and Tougaard's approach, but all suffer various limitations. Here we report a simple, non-destructive XPS depth-profiling method that yields accurate depth information with nanometre resolution. We demonstrate the technique using self-assembled multilayers on gold surfaces; the former contain 'marker' monolayers that have been inserted at predetermined depths. A controllable potential gradient is established vertically through the sample by charging the surface of the dielectric overlayer with an electron flood gun. The local potential is probed by measuring XPS line shifts, which correlate directly with the vertical position of atoms. We term the method 'controlled surface charging' and expect it to be generally applicable to a large variety of mesoscopic heterostructures.