光纤编码器的研制

近年来随着光纤技术的发展,各种光纤传感器日臻完善。我们先后制作出光纤微压力传感器、光纤液位传感器、光纤高温传感器以及用于化学溶液的浓度测量等系列光纤传感器。由于社会和生产的需要,在我所过去研究工作的基础上,又研制出光纤编码器的实验样机。本文阐述研制的光纤编码器的工作原理、设计制作及技术指标。并对其应用范围进行讨论。     

Up-regulation of Na expression in the area postrema of total sleep deprived rats by TOF-SIMS analysis

Area postrema (AP) is a circumventricular organ plays an important role in sodium homeostasis and cardiovascular regulation. Since sleep deficiency will cause cardiovascular dysfunction, the present study aims to determine whether sodium level would significantly alter in AP following total sleep deprivation (TSD). Sodium level was investigated in vivo by time-of-flight secondary ion mass spectrometry (TOF-SIMS). Clinical manifestation of cardiovascular function was demonstrated by mean arterial pressure (MAP) values. Results indicated that in normal rats, TOF-SIMS spectrum revealed a major peak of sodium ion counting as 5.61 × 10⁵ at m/z 23. The sodium ions were homogeneous distributed in AP without specific localization. However, following TSD, the sodium intensity was relatively increased (6.73 × 10⁵) and the signal for sodium image was strongly expressed throughout AP with definite spatial distribution. MAP of TSD rats is 138 ± 5 mmHg, which is significantly higher than that of normal ones (121 ± 3 mmHg). Regarding AP is an important area for sodium sensation and development of hypernatremic related sympatho-excitation; up-regulation of sodium expression following TSD suggests that high sodium level might over-activate AP, through complex neuronal networks involving in sympathetic regulation, which could lead to the formation of TSD relevant cardiovascular diseases.     

Tuning the Product Spectrum of a Glycoside Hydrolase Enzyme by a Combination of Site-Directed Mutagenesis and Tyrosine-Specific Chemical Modification

Selective chemical modification of proteins plays a pivotal role for the rational design of enzymes with novel and specific functionalities. In this study, a strategic combination of genetic and chemical engineering paves the way for systematic construction of biocatalysts by tuning the product spectrum of a levansucrase from Bacillus megaterium (Bm-LS), which typically produces small levan-like oligosaccharides. The implementation of site-directed mutagenesis followed by a tyrosine-specific modification enabled control of the product synthesis: depending on the position, the modification provoked either enrichment of short oligosaccharides (up to 800 % in some cases) or triggered the formation of high molecular weight polymer. The chemical modification can recover polymerization ability in variants with defective oligosaccharide binding motifs. Molecular dynamic (MD) simulations provided insights into the effect of modifying non-native tyrosine residues on product specificity.     

The effect of dielectric exclusion on the rejection performance of inhomogeneously charged polyamide nanofiltration membranes

Journal of Nanoparticle Research - A green bioreduction method was used to prepare highly efficient supported TiO2 photocatalysts with bimetallic (Au-Ag) nanoparticles at room temperature using...     

Ab initio simulations of liquid electrolytes for energy conversion and storage

Understanding physicochemical properties of liquid electrolytes is essential for predicting and optimizing device performance for a wide variety of emerging energy technologies, including photoelectrochemical water splitting, supercapacitors, and batteries. In this work, we review recent progress and open challenges in predicting structural, dynamical, and electronic properties of the liquids using first-principles approaches. We briefly summarize the basic concepts of first-principles molecular dynamics (FPMD), and we discuss how FPMD methods have enriched our understanding of a number of liquids, including aqueous solutions, organic electrolytes and ionic liquids. We also discuss technical challenges in extending FPMD simulations to the study of liquid electrolytes in more complex environments, including the interface between electrolytes and electrodes, which is a key component in many energy storage and conversion systems.     

Some results on linear nabla Riemann-Liouville fractional difference equations

In this paper, we establish some criteria for boundedness, stability properties, and separation of solutions of autonomous nonlinear nabla Riemann-Liouville scalar fractional difference equations. To derive these results, we prove the variation of constants formula for nabla Riemann-Liouville fractional difference equations.     

Predicting 19F NMR Chemical Shifts: A Combined Computational and Experimental Study of a Trypanosomal Oxidoreductase–Inhibitor Complex

The absence of fluorine from most biomolecules renders it an excellent probe for NMR spectroscopy to monitor inhibitor–protein interactions. However, predicting the binding mode of a fluorinated ligand from a chemical shift (or vice versa) has been challenging due to the high electron density of the fluorine atom. Nonetheless, reliable ¹⁹F chemical-shift predictions to deduce ligand-binding modes hold great potential for in silico drug design. Herein, we present a systematic QM/MM study to predict the ¹⁹F NMR chemical shifts of a covalently bound fluorinated inhibitor to the essential oxidoreductase tryparedoxin (Tpx) from African trypanosomes, the causative agent of African sleeping sickness. We include many protein–inhibitor conformations as well as monomeric and dimeric inhibitor–protein complexes, thus rendering it the largest computational study on chemical shifts of ¹⁹F nuclei in a biological context to date. Our predicted shifts agree well with those obtained experimentally and pave the way for future work in this area.