Multifunctional core–shell nanoparticles: superparamagnetic,mesoporous, and thermosensitive

Multifunctional core–shell composite nanoparticles (NPs) have been developed by the combination of three functionalities into one entity, which is composed of a single Fe₃O₄ NP as the magnetic core, mesoporous silica (mSiO₂) with cavities as the sandwiched layer, and thermosensitive poly(N-isopropylacrylamide-co-acrylamide) (P(NIPAAm-co-AAm)) copolymer as the outer shell. The mSiO₂-coated Fe₃O₄ NPs (Fe₃O₄@mSiO₂) are monodisperse and the particle sizes were varied from 25 to 95 nm by precisely controlling the thickness of mSiO₂-coating layer. The P(NIPAAm-co-AAm) were then grown onto surface-initiator-modified Fe₃O₄@mSiO₂ NPs through free radical polymerization. These core–shell composite NPs (designated as Fe₃O₄@mSiO₂@P(NIPAAm-co-AAm)) were found to be superparamagnetic with high r ₂ relaxivity. To manipulate the phase transition behavior of these thermosensitive polymer-coated NPs for future in vivo applications, the characteristic lower critical solution temperature (LCST) was subtly tuned by adjusting the composition of the monomers to be around the human body temperature (i.e. 37 °C), from ca. 34 to ca. 42 °C. The thermal response of the core–shell composite NPs to the external magnetic field was also demonstrated. Owing to their multiple functionality characteristics, these porous superparamagnetic and thermosensitive NPs may prove valuable for simultaneous magnetic resonance imaging (MRI), temperature-controlled drug release, and temperature-programed magnetic targeting and separation applications.     

Continuous-wave fiber cavity ring-down measurements using frequency-shifted interferometry

We present a spatial-domain fiber cavity ring-down (CRD) technique that does not require optical pulses for time-resolved detection. Instead of measuring the intensity decay rate of an optical pulse in the time domain as in conventional CRD experiments, we measure the decay rate of a CW signal in a ring-down cavity (RDC) using frequency-shifted interferometry in the spatial domain, as a function of distance traveled by the light. As a proof-of-concept demonstration, we measured fiber bend loss in a loop RDC using this technique, and a cavity loss change as low as 0.0135 dB induced by every fiber turn on a mandrel was unambiguously discerned.     

Teleportation of a two-atom entangled state via cavity decay

This paper proposes a scheme for teleporting a two-atom entangled state using leaky cavities. It uses resonant atom--cavity interaction to map the atomic state onto the cavity field. Then it utilizes the interference of polarized photons to establish the correlation between the distant sender and receiver. The advantage of the scheme is that the fidelity is independent of the cavity decay rate, atomic decay and detection efficiency.     

The luminescence of CaYBO4:RE (REEu, Gd, Tb, Ce) in VUV-visible region

Phosphors CaYBO₄:RE³⁺ (RE=Eu, Gd, Tb, Ce) were synthesized with the method of solid-state reaction at high temperature, and their vacuum ultraviolet (VUV)-visible luminescent properties in VUV-visible region were studied at 20 K. In CaYBO₄, it is confirmed that there are two types of lattice sites that can be substituted by rare-earth ions. The host excitation and emission peaks of undoped CaYBO₄ are very weak, which locate at about 175 and 350-360 nm, respectively. The existence of Gd³⁺ can efficiently enhance the utilization of host absorption energy and result in a strong emission line at 314 nm. In CaYBO₄, Eu³⁺ has typical red emission with the strongest peak at 610 nm; Tb³⁺ shows characteristic green emission, of which the maximum emission peak is located at 542 nm. The charge transfer band of CaYBO₄:Eu³⁺ was observed at 228 nm; the co-doping of Gd³⁺ and Eu³⁺ can obviously sensitize the red emission of Eu³⁺. The fluorescent spectra of CaYBO₄:Ce³⁺ is very weak due to photoionization; the co-addition of Ce³⁺-Tb³⁺ can obviously quench the luminescence of Tb³⁺.     

Generation of a four-qubit cluster state for atoms in a thermal cavity

We propose two schemes for generating a four-atom cluster state in a thermal cavity. With the assistant of a strong classical field the photon-number-dependent parts in the effective Hamiltonian are canceled. Thus the schemes are insensitive to the thermal field. The schemes can also be used to generate the cluster state for the trapped ions in thermal motion.     

第二代测序序列比对方法综述

使用聚合酶合成技术的Illumina和454平台以及使用连接酶合成测序技术的SOLiD平台是目前三种主流的第二代测序平台.对第二代测序平台产生的高通量序列片段进行比对的方法一般分为两步：①预处理,②序列比对.预处理方法有两类,即基于哈希表的方法和基于后缀trie的Burrows-Wheeler转换思想.序列比对方法也可分为两类,一是空位种子片段索引,二是Smith-Waterman动态规划算法.本文使用Illumina和SOLiD两种平台产生的数据对常用的比对软件SHRiMP,MAQ,BFAST,BWA,BOWTIE等进行了单机测试,结果显示：BOW-TIE在对Illumina平台数据进行比对时,在内存使用、比对速度以及准确性等方面表现比其他几种好,BWA比较适合用于比对SOLiD平台产生的数据.在处理第二代以及以纳米孔技术为标志的第三代测序平台高通量数据时,第二代比对技术仍不能完全满足要求,本文认为以云计算为基础的新序列比对方法是未来研究和发展的一个重要方向.     

光学自由曲面数控化加工方法

在光学系统中，为了满足特殊的成像要求，需要使用自由曲面光学零件，但由于自由曲面是一类非常复杂的曲面，用传统的光学加工方法很难加工。本文概要介绍了光学非球面的多种加工方法，探索了这些方法加工光学自由曲面的可能性，提出了用数控化加工方法加工光学自由曲面，并利用这种方法加工了一块自由曲面透镜。     

水溶性维生素核磁共振定量分析的研究

药物核磁共振定量分析法,操作简便,样品用量少,定性鉴定和定量分析同步完成,无须被测物的标准对照品,只须一般内标即可完成定量分析,分析速度和精密度可以达到或接近HPLC法. 作为药物的水溶性维生素,中国药典中还没有核磁共振定量分析方法. 实验数据表明,用核磁共振定量分析法与中国药典中提供的水溶性维生素分析法的分析结果十分吻合,可以达到药品市场监管的要求.     

Long pulse duration of the UV laser with a multi-reflected cavity: Experiment and modeling

The long pulse operation of ultraviolet (UV) laser attributed to multi-reflection is presented on an acousto-optic (AO) Q-switched ultraviolet laser system blocking green light inside a cavity. The ultraviolet laser with the highest average power of 456 mW is obtained with 20 kHz repetition-rate. The numerical simulation of UV pulse broadening was studied using Gaussian curve approximation. The conclusion suggests that the short multi-reflected cavity and high incident pump power will be beneficial to alleviate the width broadening effect. The results, for the first time, would provide the technology for controlling the pulse width of an AO Q-switched DUV laser.