脱乙酰基对天然魔芋葡甘聚糖分子形貌的影响

通过原子力显微镜直接观察魔芋葡甘聚糖（KGM）分子的三维结构形貌，KGM水溶液铺展在经Ca^2 处理的云母片上，干燥固定后，可获得稳定，重复的图像，实验结果表明，稀溶液中KGM分子具有伸展的螺旋链状结构，单股的长度达200－400nm，厚度为1．0nm，宽度为35．0－35．2nm，脱乙酰后分子链卷曲成直径约40－50nm,厚3．5－5．0nm的弹性圆台状。     

Review of near-field optical microscopy

This review has introduced a new near-field optical microscope (NOM)—atomic force microscope combined with photon scanning tunneling microscope (AF / PSTM). During scanning, AF/PSTM could get two optical images of refractive index image and transmissivity image, and two AFM images of topography image and phase image. A reflected near-field optical microscope (AF/RSNOM) has also been developed on AF/PSTM platform. The NOM has been reviewed in this paper and the comparison between AF/PSTM & RSNOM and the commercial A-SNOM & RNOM has also been discussed. The functions of AF/PSTM & RSNOM are much better than A-SNOM & RNOM.     

辣根过氧化物酶活性膜结构及生物电催化性能

通过分子沉积法研究了在聚对苯二甲酸乙二醇酯（PET）表面及金电极表面组装辣根过氧化物酶（HRP）/聚对苯乙烯磺酸钠（PSS）多层生物活性膜，用原子力显微镜(AFM)研究了组装膜的表面形貌，并研究了组装膜的形貌、粗糙度和活性关系.应用循环伏安法（CV）研究了组装HRP膜后电极对H2O2的电化学催化还原作用.实验发现，采用亚甲基蓝（MB）溶液为介质，在H2O2浓度为0.2～5.0 mmol•L－1时，其响应电流对H2O2浓度变化基本呈线性.     

Subject Index to Volume 33

This paper reports the investigation of microdroplet sample preparation for phosphate, strontium and rubidium using X-ray fluorescence. Sample filter papers were prepared by drying under several different conditions and the front and the back sides of the filter papers were measured using X-ray fluorescence (XRF), scanning electron microscopy (SEM), X-ray diffraction (XRD), and electron-probe microanalysis (EPMA).

It was reported by Murata and Murokado that the elemental distribution difference between the front and the back sides after drying the filter paper led to erratic data.¹ It has been found that the intensity difference between the front and the back sides was due to the condensation of the material of interest on the surface of the filter papers and the amount of the condensed material on the filter paper was related to the temperature at which the filter paper was dried.

Optimum temperature at which a filter paper is dried and an appropriate internal standard are essential to reproducible measurements.     

人体胆结石难溶物的扫描电镜观察和红外光谱研究

用傅里叶变换红外光谱仪和扫描电镜研究了胆色素型和混合型胆结石经氯仿、乙醇、乙醚、盐酸等溶剂溶解剩余的主要组分和微观结构。结果表明，胆红素盐、蛋白质、脂肪酸盐、碳酸钙等为难溶物；棕色色素胆石中的蛋白质的二级结构似a-螺旋为主。扫描电镜观察显示，在色素型和混合型胆石难溶物中都出现了可能为蛋白质的薄膜带状物，讨论了难溶物与结石形成的关系。     

Thermodynamic Performance Characteristics of a Brownian MicroscopicHeat Engine Driven by Discrete and Periodic Temperature Field

A Brownian microscopic heat engine with a particle hopping on a one-dimensional lattice driven by a discrete and periodic temperature field in a periodic sawtooth potential is investigated. In order to clarify the underlying physical pictures of the heat engine, the heat flow via the potential energy and the kinetic energy of the particles are considered simultaneously. Based on describing the jumps among the three states, the expressions of theefficiency and power output of the heat engine are derived analytically. The general performance characteristic curves are plotted by numerical calculation. It is found that the power output-efficiency curve is a loop-shaped one, which is similar to one for a real irreversible heat engine. The influence of the ratioof the temperature of the hot and cold reservoirs and the sawtooth potential on the maximum efficiency and power output is analyzed forsome given parameters. When the heat flows via the kinetic energy isneglected, the power output-efficiency curve is an open-shaped one,which is similar to one for an endroeversible heat engine.     

原子力显微术轻敲模式中探针样品接触过程及相位衬度研究

借助简单的有阻尼受迫振子模型，研究了原子力显微术轻敲模式中探针与样品接触时间t_c、样品的表面形变D_z和相位衬度对探针设置高度z_c及样品杨氏模量E_s的依赖关系.结果发现,t_c与D_z均随E_s及z_c的增大而减小，同时探针与样品作用过程伴随很小的能量耗散.对轻敲过程中相移量φ的研究表明，E_s较大的样品有较小的φ，且φ随 关键词： 原子力显微术 轻敲模式 相位衬度     

Nano-crater formation on a Si(1 1 1)-(7 × 7) surface by slow highly charged ion-impact

Using scanning tunneling microscopy (STM) and time of flight secondary ion mass spectrometry (TOF/SIMS), we observed radiation effects on a Si(1 1 1)-(7 × 7) surface in the collision of a single highly charged ion (HCI) with a charge state q up to q = 50. The STM observation with atomic resolution revealed that a nanometer sized crater-like structure was created by a single HCI impact, where the size increased rapidly with q. The secondary ion yields also increased with q in which multiply charged Si ions (Siⁿ⁺) were clearly observed in higher q HCI-collisions. The sputtering mechanism is briefly discussed, based on the so-called Coulomb explosion model.     

Ionic liquid–modified cellulosic hydrogels for loading and sustained release of selenourea: an ensuing inhibition of tyrosinase activity

Cellulose-based hydrogel materials were prepared and modified with tannic acid and l-methionine using ionic liquid as the solvent. The gels were prepared to develop a sustained release medium for selenourea (SeU). The drug delivery characteristics of selenourea-loaded cellulose (CSeU), selenourea-loaded tannic acid-modified cellulose (CTSeU), and selenourea-loaded L-methionine-modified cellulose (CMSeU) were investigated in aqueous media and simulated gastric fluid (SGF) media. This modified gel beads have been characterized using field emission scanning electron microscope, X-ray energy-dispersive spectroscopy, Fourier transform infrared spectroscopy, thermogravimetry–differential thermal analysis and swelling properties and compared with those of the unmodified ones. We also investigated the inhibitory effects of SeU released from these gels on the activity of mushroom tyrosinase. Out of all the gel materials, CTSeU showed maximum SeU release both in water and SGF media. However, tyrosinase inhibitory action in PBS medium was comparable for all the three gel materials.     

铸态Mg-Zn-Gd合金中准晶相的应变速率敏感性研究

利用纳米压痕仪、原子力显微镜以及电子显微镜等性能与显微结构分析手段对镁基二十面体准晶的应变速率敏感性问题进行了研究.在室温下对铸态Mg79.4-Zn18.5-Gd2.1(at.%)合金中形成的网状准晶相进行纳米压入测试,比较了不同压入应变速率下压痕的压入曲线、表面形貌差异,并据此对准晶相的压入变形行为进行了研究.结果表明,准晶相的室温硬度对应变速率敏感,其变形行为与常规金属及合金相比具有特殊性.结合准晶原子团簇摩擦变形理论,对反映准晶特性的压入实验现象进行了分析和讨论.