大型火箭起飞横向漂移测量系统研究

本文论及了大型火箭发射起飞段横向漂移量的近距离高速摄影测量系统和数据处理方法。     

直流电机的数字同步锁相

在某高速摄影机中,我们采用了同步数字锁相环路,本文叙述该机中直流电机的数字同步锁相原理及其所用数字相位误差积分器线路的构成。     

Signature invariants of covering links

We apply the theory of signature invariants of links in rational homology spheres to covering links of homology boundary links. From patterns and Seifert matrices of homology boundary links, we derive an explicit formula to compute signature invariants of their covering links. Using the formula, we produce fused boundary links that are positive mutants of ribbon links but are not concordant to boundary links. We also show that for any finite collection of patterns, there are homology boundary links that are not concordant to any homology boundary links admitting a pattern in the collection.

     

Spectroscopic Observation of the Hydroxy Position in Butanol Hydrates and Its Effect on Hydrate Stability

In this study, we investigate the crystal structures and phase equilibria of butanols+CH₄+H₂O systems to reveal the hydroxy group positioning and its effects on hydrate stability. Four clathrate hydrates formed by structural butanol isomers are identified with powder X‐ray diffraction (PXRD). In addition, Raman spectroscopy is used to analyze the guest distributions and inclusion behaviors of large alcohol molecules in these hydrate systems. The existence of a free OH indicates that guest molecules can be captured in the large cages of structure II hydrates without any hydrogen‐bonding interactions between the hydroxy group of the guests and the water‐host framework. However, Raman spectra of the binary (1‐butanol+CH₄) hydrate do not show the free OH signal, indicating that there could be possible hydrogen‐bonding interactions between the guests and hosts. We also measure the four‐phase equilibrium conditions of the butanols+CH₄+H₂O systems.     

自紧身管临界裂纹尺寸的概率断裂力学研究

基于概率断裂力学理论和Mome Caflo模拟方法，本文进行了自紧身管临界裂纹尺寸的可靠性研究。自紧身管内表面的疲劳裂纹考虑为半椭圆形式。裂纹尖端处的应力强度因子由内压和自紧残余应力共同产生。自紧残余应力采用了符合身管材料具有强化和包辛格效应性能推导的公式计算，它产生的应力强度因子通过权函数方法得到。根据断裂准则，可计算出自紧身管的临界裂纹尺寸。实例分析表明，对数正态分布为临界裂纹尺寸的最佳分布，同时给出了在各种置信度和可靠度下自紧身管的临界裂纹尺寸。     

Antioxidant encapsulated porous poly(lactide-co-glycolide) microparticles for developing long acting inhalation system

The purpose of this study was to fabricate porous poly(lactide-co-glycolide) (PLGA) microparticles for efficient pulmonary deposition and increased therapeutic duration of the antioxidant anthocyanin (ATH). These microparticles were prepared by a water-in-oil-in-water (W(1)/O/W(2)) multi-emulsion method with vaporizing ammonium bicarbonate (AB) as a porogen and starch as a viscous additive. High porosity achieved by the decomposition reaction of AB to the base of ammonia, carbon dioxide, and water vapor at 50°C enabled efficient deposition of ATH throughout the entire lung in BALB/c mice. In addition, the porous microparticles incorporating starch showed sustained ATH release characteristics (up to 5 days) and protracted antioxidant activity (up to 5 days) for 2,2-diphenyl-1-pikryl-hydrazyl (DPPH) radicals, which was comparable to that of the porous microparticles without starch which completely released ATH in 2h. Furthermore, these porous microparticles incorporating starch led to longer ATH residence (up to 20 days) in in vivo lung epithelium. We believe that this system has great pharmaceutical potential as a long-acting antioxidant for continuously relieving oxidative stress in pulmonary diseases like chronic obstructive pulmonary disease (COPD).     

Microbiosensors based on DNA modified single-walled carbon nanotube and Pt black nanocomposites

Glucose and ATP biosensors have important applications in diagnostics and research. Biosensors based on conventional materials suffer from low sensitivity and low spatial resolution. Our previous work has shown that combining single-walled carbon nanotubes (SWCNTs) with Pt nanoparticles can significantly enhance the performance of electrochemical biosensors. The immobilization of SWCNTs on biosensors remains challenging due to the aqueous insolubility originating from van der Waals forces. In this study, we used single-stranded DNA (ssDNA) to modify SWCNTs to increase solubility in water. This allowed us to explore new schemes of combining ssDNA-SWCNT and Pt black in aqueous media systems. The result is a nanocomposite with enhanced biosensor performance. The surface morphology, electroactive surface area, and electrocatalytic performance of different fabrication protocols were studied and compared. The ssDNA-SWCNT/Pt black nanocomposite constructed by a layered scheme proved most effective in terms of biosensor activity. The key feature of this protocol is the exploitation of ssDNA-SWCNTs as molecular templates for Pt black electrodeposition. The glucose and ATP microbiosensors fabricated on this platform exhibited high sensitivity (817.3 nA/mM and 45.6 nA/mM, respectively), wide linear range (up to 7 mM and 510 μM), low limit of detection (1 μM and 2 μM) and desirable selectivity. This work is significant to biosensor development because this is the first demonstration of ssDNA-SWCNT/Pt black nanocomposite as a platform for constructing both single-enzyme and multi-enzyme biosensors for physiological applications.     

Microproteomic analysis of 10,000 laser captured microdissected breast tumor cells using short-range sodium dodecyl sulfate-polyacrylamide gel electrophoresis and porous layer open tubular liquid chromatography tandem mass spectrometry

Precise proteomic profiling of limited levels of disease tissue represents an extremely challenging task. Here, we present an effective and reproducible microproteomic workflow for sample sizes of only 10,000 cells that integrates selective sample procurement via laser capture microdissection (LCM), sample clean-up and protein level fractionation using short-range SDS-PAGE, followed by ultrasensitive LC-MS/MS analysis using a 10 μm i.d. porous layer open tubular (PLOT) column. With 10,000 LCM captured mouse hepatocytes for method development and performance assessment, only 10% of the in-gel digest, equivalent to ～1000 cells, was needed per LC-MS/MS analysis. The optimized workflow was applied to the differential proteomic analysis of 10,000 LCM collected primary and metastatic breast cancer cells from the same patient. More than 1100 proteins were identified from each injection with >1700 proteins identified from three LCM samples of 10,000 cells from the same patient (1123 with at least two unique peptides). Label free quantitation (spectral counting) was performed to identify differential protein expression between the primary and metastatic cell populations. Informatics analysis of the resulting data indicated that vesicular transport and extracellular remodeling processes were significantly altered between the two cell types. The ability to extract meaningful biological information from limited, but highly informative cell populations demonstrates the significant benefits of the described microproteomic workflow.