Gamma-Irradiated Gelatin-Based Films Modified by HEMA for Medical Application

The present article describes the synthesis and characterization of bi-component polymer systems based on gelatin films incorporated with 2-hydroxyethyl methacrylate (HEMA) monomer, developed for medical application. Gelatin films were prepared by the addition of HEMA of different concentrations (0–30 wt.%) and irradiated with various radiation doses (0–5 kGy). Tensile strength and tear strength of the irradiated gelatin films were found to increase with increasing HEMA up to 20 wt.% as well as radiation doses (1 kGy) as optimized. The maximum tensile and tear strengths of irradiated gelatin films with HEMA were found to be 79.1 MPa and 83.2 N/mm, respectively, at the optimum conditions, and these values were about double that of a reference film prepared without additives. In addition, morphological analysis was done by scanning electron microscopy (SEM) and showed how HEMA cemented and was covered with gelatin in the blend. Thermomechanical analysis was carried out to investigate the shifting of glass transition temperature (T_g) towards higher temperature due to HEMA addition, and the effect of this film was tested on the human body in order to determine whether it can be applied for medical purposes.     

Rapid identification of trimethyl and triethyl amines using sulphonic acidic ionic liquids: A time-of-flight secondary ion mass spectrometry study of fragmentation reactions

The time-of-flight secondary ion mass spectrometry (TOF-SIMS) has emerged as a powerful tool for the unswerving detection of biomolecules, in particular, proteins and peptides. To date, there is very little information available on the direct determination of trimethyl/triethyl amines using TOF-SIMS. One major hurdle in this regard is an ultrahigh vacuum system, usually needed in TOF-SIMS, which hampers its usability to trimethyl/triethyl amines owing to their high evaporation rate. We designed an efficient and sensitive protocol for rapid identification and sensitive determination of tertiaryalkyl amines using TOF-SIMS. The amines were derivatized by reaction with 1,4-butane sultone and sulphuric acid sequentially to afford the corresponding sulphonic acidic ionic liquids (ILs). The TOF-SIMS analysis of these task-specific ILs (TSILs) was carried out in both positive and negative polarity. The positive ion mass spectra of TSILs showed sharp fragmented peaks for tertiaryalkyl amines at typical level and up to 10 ppm. The possible mechanism for different fragmentation pathways in positive polarity was discussed.     

计算机辅助装调与传统基准传递技术相结合实现三镜消像散系统的装调

为满足复杂航天光学系统对精度的要求,克服传统基准传递技术与计算机辅助装调技术对多于3片反射镜的复杂光学系统进行装调时存在的局限性,提出了两种技术相结合的装调方法。采用提出的方法对三镜消像散(TMA)空间相机进行了装调,结果显示:三镜在Y向和Z向的失调量分别由18.651和9.879 mm降低到1.036和0.102 mm,系统波前差达到全视场平均值1/14λ(RMS)。结果证明:此方法能有效缩短装调时间并达到系统要求的精度指标,对于多镜复杂光学系统装调具有指导和参考价值。     

离轴三反测绘相机调焦机构的设计

针对测绘相机对相机成像质量和内方位元素稳定性的要求,在分析3种调焦方式特点的基础上,确定了符合离轴三反测绘相机需要的调焦方式。设计了滚珠丝杠驱动的直线导轨式调焦机构,计算得到调焦机构的灵敏度为0.2μm。对该调焦机构进行了精度检测和试验验证,结果显示其指向精度〈2″,定位精度〈3μm。得到的结果表明：该空间调焦机构具有结构紧凑、刚度高、位移精度好等特点,能够满足离轴三反测绘相机的调焦要求。     

Bearings-Only Target Motion Analysis Using a Dual-Waveband Infrared System

Infrared systems are widely used for target detection, designation and tracking. For example, an Infrared Search and Track (IRST) system, as a typical airborne or shipboard detecting device, is widely equipped for the remote target detection and tracking. In recent years, the problem of target motion analysis (TMA) and tracking has been studied increasingly extensively. In an airborne infrared system, the problem becomes more difficult due to absence of range information. In this paper, the infrared model and motion model of typical aerial targets are described. An airborne dual-waveband IRST system, which is quite familiar nowadays, is choosed for implementation of target motion analysis. Based on the above, a novel and more practical algorithm of target tracking via bearings-only measurements is formed and the major parameters are defined according to a typical airborne dual-waveband IRST system. Finally, data simulation is implemented, and the results demonstrate the new algorithm has a better performance than before for bearings-only target tracking.     

Temperature Calibration of TMAs Using Modulated Temperature and Curie Temperature Reference Standards

This article presents the concept of calibrating temperature in thermomechanical analyzers (TMA) using reference standard magnetic materials whose Curie temperatures are well-known. This concept has not been tested experimentally to the best of the author's knowledge. Electrical current applied to a unifilarly wound furnace results in the furnace acting as an electrical inductor. A magnetic material sample located within such a furnace practically constitutes a solenoid core. A modulated temperature program directly results in a corresponding varying force exerted by the sample against the TMA probe, if the probe's axis and the central induced magnetic field line of force are coaxial, and, furthermore, if the direction of the central magnetic field line of force and the expansion direction of the probe are identical. If a sample undergoes a Curie transition, then the force which the sample exerts against the probe will diminish to zero as the transition goes to completion. Using a modulated temperature program throughout this phase transition allows determination of transition completion, by observation of the point at which the force required to maintain the sample's physical position reaches a steady state from it's previously non-steady state. This revised version was published online in August 2006 with corrections to the Cover Date.     

Thermal study of irradiated polyacetylene films

Polyacetylene films irradiated by-rays up to 100 MRad were studied by means of TMA, DTG and DSC methods.It is shown that as the irradiation dose increases the concentration of topological branching knots into the polymer chains and theT _g values decrease, the total mass loss and the enthalpy of the thermal isomerization reaction also decrease.     

Morphological and structural change of nano-pored alumina membrane above 1200 K

The transition and the change in pore morphology of a porous alumina membrane prepared by anodically oxidizing aluminum in sulfuric acid were studied mainly by TG-DTA, TMA, dilatometry and TEM. At ca. 1243 K, TMA showed an expansion followed by contraction; the CO₂ and SO₂ gases were quickly discharged, and the pore morphology of the as-prepared porous membrane (ca 150 mm-t, with pores ca 25 nm in diameter and containing ca 11% by mass of SO₂) showed an abrupt change, but the pores were retained to ca. 1573 K. Sulfur incorporated in the membrane was lost in two stages, i.e., at ca 1243 K and in a range up to 1373 K. Isothermal measurements revealed the complex crystallization of the amorphous phase into polycrystalline phase. This revised version was published online in August 2006 with corrections to the Cover Date.     

Industrial standardization of thermal analysis in Japan

To satisfy the needs for industrial standards for thermal analysis in the Japanese polymer industry, round-robin tests of differential scanning calorimetry (DSC), thermogravimetry (TG), thermomechanical analysis (TMA) and thermodilatometry (TD) have been carried out recently. The results are discussed in this short review. The DSC applications tested were not only for determination of transition temperature but also for measurements of the transition heat and heat capacity. The TG task group did not aim at longterm thermal endurance studies, but relative thermal stability in molding and estimation of filler content, residual solvent content, etc. TMA was found to be a useful tool for measuring softening temperature and heat distortion temperature, especially for high-temperature engineering plastics, instead of the Vicat test which has temperature limitations. For temperature calibration of DSC and TG, ICTA-NIST certified reference materials were used together with other potential temperature standards; some inorganic substances and alloys were not found to be preferable to pure metals. For TMA and TD metal plates were found to be very useful for temperature calibration. Analysis of the round-robin test results also clarified present status of practical applications of thermal analysis, such as reproducibility and causes of errors. Plenary lecture     

Thermal And Structural Characterization of Commercial α-, β-, and γ-Cyclodextrins

α-, β-, and γ-cyclodextrins (CDs) marketed by five different companies were characterized from the thermal and structural point of view. Three αCD samples showed two-step DSC dehydration profiles and their XRD patterns were characteristic for αCD⋅6H₂O form I, whereas one brand with an apparent three-step DSC dehydration behaviour was a mixture of αCD⋅6H₂O form I and anhydrous αCD. The differences in the DSC profiles after dehydration and EGA onset decomposition temperatures recorded for the five βCD brands were attributed to different manufacturing and purification processes. The five γCDs brands showed a common thermal behaviour and very similar XRD patterns. The patterns did not match the idealized pattern of γCD⋅14.1H₂O, indicating the occurrence of two different hydrated crystal structures. This revised version was published online in August 2006 with corrections to the Cover Date.