液相色谱-质谱用于卵巢肿瘤中磷脂轮廓的分析

卵巢肿瘤日益影响女性的健康和生活质量,其中的卵巢癌是女性三大恶性肿瘤之一,死亡率高居三者之首。因此卵巢肿瘤尤其卵巢癌是目前的一个研究热点。本研究利用液相色谱-质谱(LC-MS)联用技术对卵巢肿瘤进行磷脂轮廓分析,研究良性卵巢肿瘤(B)和卵巢癌(M)的患者血清中磷脂代谢的差异情况。首先用LC-MS采集血清中磷脂的指纹图谱,通过峰识别、峰匹配等得到峰表,然后利用正交校正的偏最小二乘法(OSC-PLS)进行多种分型,根据模型的变量重要因子(VIP)、VIP值的置信区间、S图和显著性差异检验结果等筛选有差异的磷脂。结果显示: M组和B组与正常对照(N)组比较都存在明显的磷脂代谢差异,发生改变的磷脂主要为缩醛磷脂酰乙醇胺、磷脂酰胆碱、缩醛磷脂酰胆碱、鞘磷脂和溶血磷脂酰胆碱。     

GaN hexagonal pyramids formed by a photo-assisted chemical etching method

A series of experiments were conducted to systematically study the effects of etching conditions on GaN by a con-venient photo-assisted chemical （PAC） etching method. The solution concentration has an evident influence on the surface morphology of GaN and the optimal solution concentrations for GaN hexagonal pyramids have been identified. GaN with hexagonal pyramids have higher crystal quality and tensile strain relaxation compared with as-grown GaN. A detailed anal- ysis about evolution of the size, density and optical property of GaN hexagonal pyramids is described as a function of light intensity. The intensity of photoluminescence spectra of GaN etched with hexagonal pyramids significantly increases compared to that of as-grown GaN due to multiple scattering events, high quality GaN with pyramids and the Bragg effect.     

Synthesis and infrared and fluorescence spectra of new europium and terbium polynuclear complexes with an amide-based 1,10-phenanthroline derivative

An amide-based 1,10-phenanthroline (phen) derivative and its complexes with europium(III) and terbium(III) ions were synthesized. The complexes were characterized by elemental analysis, infrared spectra and conductivity. The europium and terbium ions were coordinated by O atoms of C=O, Ar-O-C and N atoms of phen. The fluorescence properties of the complexes in THF, dioxane, MeCN and DMF were investigated. Under the excitation of UV light, these complexes exhibited characteristic fluorescence of europium and terbium ions. The solvent factors influencing the fluorescent intensity were discussed.     

SBT-memristor-based crossbar memory circuit

Implementing memory using nonvolatile, low power, and nano-structure memristors has elicited widespread interest. In this paper, the SPICE model of Sr_0.95Ba_0.05TiO₃ (SBT)-memristor was established and the corresponding characteristic was analyzed. Based on an SBT-memristor, the process of writing, reading, and rewriting of the binary and multi-value memory circuit was analyzed. Moreover, we verified the SBT-memristor-based 4×4 crossbar binary and multi-value memory circuits through comprehensive simulations, and analyzed the sneak-path current and memory density. Finally, we apply the 8×8 crossbar multi-value memory circuits to the images memory.     

Approach to Single-Mode Dominated Resonant Emission in Ga N-Based Square Microdisks on Si

Square microdisks with round corners are fabricated using a standard GaN-based blue LED on Si substrates.Whispering gallery-like inodes in the square microdisks are investigated by finite-difference time-domain simulation.The simulation results reveal that the round corners in square microdisks can substantially suppress the number of light propagation paths and further reduce the number of optical modes.A con focal microphotoluminescence is performed to analyze the optical properties of the squ...     

Human fibrinogen adsorption onto single-walled carbon nanotube films

The adsorption behavior of human fibrinogen (Hfg) on single-walled carbon nanotube (SWNT) films was investigated using scanning electron microscopy (SEM) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. It was shown in the SEM images that fibrinogen was adsorbed strongly on the surface of SWNT when the samples were incubated in the Hfg solutions for 10 min. The dependence of adsorption on the concentration of fibrinogen was also investigated and it was found that adsorption increased with increasing concentration. In order to further explore the adsorption of fibrinogen on SWNT surface, NEXAFS spectra were obtained at the N K-edge and the C K-edge. The results confirmed the conclusion regarding the dependence of adsorption on fibrinogen concentration. It is demonstrated that, due to its high sensitivity to the surface elements, NEXAFS spectroscopy is a powerful tool to investigate the adsorption of fibrinogen on SWNT films.     

High-field-induced electron detrapping in An AlGaN/GaN high electron mobility transistor

A step stress test is carried out to study the reliability characteristics of an AlGaN/GaN high electron mobility transistor(HEMT).An anomalous critical drain-to-gate voltage with a negative temperature coefficient is observed in the stress sequence,beyond which the HEMT device starts to recover from degradation induced by early lower voltage stress.While the performance degradation featuring the drain current slump stems from electron trapping in the surface or bulk states during low-to-medium bias stress,the recovery is attributed to high field induced electron detrapping.The carrier detrapping mechanism could be helpful for lessening the trapping-related performance degradation of a GaN-based HEMT.     

利用金属有机物化学气相沉积技术生长的a面GaN表面形貌和位错的研究

采用金属有机物化学气相淀积技术在r面蓝宝石衬底上制备了a面GaN薄膜,用熔融的KOH在400 ℃对样品分别腐蚀1.0,1.5和2.0 min.用扫描电镜、原子力显微镜、X射线衍射谱和阴极射线荧光对腐蚀前后的表面形貌进行分析.研究表明,400 ℃下腐蚀1.5 min后出现了长平行四边形的条纹状,这是由于无极化的a面GaN表面极性各向异性,c向与m向上N原子悬挂键密度不同,同时稳定性不同,对OH^-离子的吸附能力不同造成的,其中沿c方向易于腐蚀.同时,a面GaN腐蚀后出现了六角突起.我们认为这与穿透位错有关,而其形貌则与GaN薄膜的位错局部极性有关. 关键词： a面GaN')" href="#">a面GaN 堆垛层错 极性     

GaN1-xPx薄膜的结构特性研究

用金属有机物化学气相沉积技术在蓝宝石衬底上外延了高P组分的GaN1-xPx 薄膜.利用x射线衍射仪和拉曼光谱仪研究了P对GaN1-xPx晶体结构的影响.研究结果表明:随着P组分比的增加,GaN1-xPx(0002)衍射峰逐渐向小角度移动,即晶格常数变大;与非掺杂GaN相比,GaN1-xPx薄膜的拉曼光谱中出现了4个新的振动模式,将它们分别归因于P族团引起的准局部振动模式、Ga-P键振动引起的间隙模,以及来自缺陷引起的无序激活散射.同时,随着P组分比的增加,A1(LO)模式的频率向低频方向移动,这种红移现象起因于合金化和应变的影响.     

GaN1-xPx薄膜的结构特性研究

用金属有机物化学气相沉积技术在蓝宝石衬底上外延了高P组分的GaN_1-xP _x 薄膜.利用x射线衍射仪和拉曼光谱仪研究了P对GaN_1-xP_x晶体结构 的影响.研究结果表明：随着P组分比的增加，GaN_1-xP_x（0002）衍射 峰逐渐向小角度移动，即晶格常数变大；与非掺杂GaN相比，GaN_1-xP_x薄 膜的拉曼光谱中出现了4个新的振动模 关键词： 1-xP_x')" href="#">GaN_1-xP_x 金属有机物化学气相沉积 x射线衍射 拉曼光谱