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排序方式: 共有595条查询结果,搜索用时 15 毫秒
1.
Corsaro MM Piaz FD Lanzetta R Naldi T Parrilli M 《Rapid communications in mass spectrometry : RCM》2004,18(8):853-858
The use of the electrospray ionization quadrupole time-of-flight tandem mass spectrometry (ESI-QTOFMS) technique for the structural determination of Lipid A from Pseudomonas corrugata is described. This technique appears to be more sensitive with respect to other commonly used tandem mass spectrometric approaches, and was very valuable in the structural determination of the highly heterogeneous Lipid A fractions. The Lipid A fraction consists mainly of a pentaacyl component in which 3-hydroxydecanoyl [10:0(3-OH)] and 3-hydroxydodecanoyl [12:0(3-OH)] are linked as primary acyl substituents to the classical bisphosphorylated beta-(1' --> 6)-linked D-glucosamine disaccharide. Secondary substitution of N-acyl fatty acids with dodecanoyl residues [12:0] and/or its 2-OH derivatives was also observed. 相似文献
2.
V Ascalone P Catalani L Dal Bo' N Deschamps P Guinebault 《Journal of chromatography. A》1987,414(1):101-108
A high-performance liquid chromatographic method has been developed for the simultaneous determination of alpidem and its metabolites in human plasma. The method involved a single extraction of the parent drug and metabolites into diethyl ether from alkalinized plasma, evaporation of the organic solution and chromatography of the extracts on a C18 column coupled to a fluorimetric detector. An internal standard was used for the quantitative determination of the compounds. The method was selective for alpidem and three of its metabolites and has a limit of detection of less than 1 ng ml-1 for all the compounds. Since the chromatographic run took more than 20 min, the chromatographic process was fully automated and performed overnight. 相似文献
3.
Gyeonghye Yim Seounghun Kang Hyungjun Kim Young‐Jin Kim Yeong‐Gyu Gil Young‐Kwan Kim Dal‐Hee Min Hongje Jang 《Advanced functional materials》2020,30(9)
The synthesis of nanostructures using homogeneous precursors in the solution phase is widely used to achieve uniformity and well‐defined morphological control. However, drawbacks such as the lack of diversity due to the limited reaction rate modulation exist. One‐step, core–shell nanorod formation using simultaneous covering synthesis using solid and ionic heterogeneous precursors is proposed in this study. A Te‐Bi2Te3/TeO2 core–shell structure is successfully synthesized by precisely controlling various influencing factors, including concentration, temperature, and pH, and its physicochemical and photochemical properties are thoroughly investigated. The proposed nanostructure overcomes the oxidation susceptibility of Te and can be applied to multipotent cancer theranostics in vitro and in vivo in combination with computed tomography imaging. 相似文献
4.
ZHANG Chang-ming LIAO Yi-tao LIU Yong-zhi DAI Ji-zhi 《光电子快报》2005,1(3):185-187
The structure of the optical waveguide of 2-bit electrooptic A/D converter with proton-exchange micro prisms is optimized by the finite-difference beam propagation method (FD-BPM) The electrode parameters of the converter are optimized by conformal mapping. The optimal parameters are a half- wave voltage of Vπ = 4.5 V and a bandwidth of △f = 1.4 GHz. A normalized transmitted power of 69.75% is obtained by FD-BMP and the output waveguide gap is 300 μm. 相似文献
5.
目的评价氩激光联合活血散瘀中药治疗视网膜分支静脉阻塞的临床疗效。方法氩激光联合活血散瘀中药治疗组40眼和单纯氩激光治疗组30眼,随访6~12月,观察视力、视网膜出血和黄斑水肿变化并行统计分析。结果联合中药治疗组患者和单纯氩激光光凝组治疗前后视力均有显著差异(P<0.05),治疗后两组最后视力比较差异显著(P<0.05),前者较后者视力进步明显。而且联合中药治疗出血吸收情况明显优于前组(P<0.05),并且两组黄斑水肿发生率治疗前后均有显著差异(P<0.05),虽然治疗6月后两组黄斑水肿发生率无显著差异(P>0.05),但后者较前者发生率低。结论氩激光光凝联合活血散瘀中药治疗更能促使视网膜分支静脉阻塞患者的出血吸收、黄斑水肿减轻及视功能的改善,在总体上取得了更好的治疗效果。 相似文献
6.
Fuqin Zheng Wanfu Zhang Xiaoxia Zhang Youlin Zhang Wei Chen 《Advanced functional materials》2021,31(43):2103318
Water oxidation is a critical process for electrochemical water splitting due to its inherent sluggish kinetics. In spite of the high catalytic activities of noble metal-based electrocatalysts for water oxidation, their high cost, rare reserves, and low stabilities drive researchers to exploit efficient but low-cost electrocatalysts. Ultrathin 2D nanomaterials are considered efficient electrocatalysts for oxygen evolution reaction (OER) in water splitting. Herein, a facile strategy is proposed to fabricate 2D FeNi layered double hydroxide (FeNi-LDH) nanosheets packed with the in situ produced 1D sword-like FeNi-MOFs by using FeNi-LDH as a semi-sacrificial template. In the composite, the thickness of the formed nanosheets is only 1.34 nm, much thinner than that of most previously reported 2D materials. The 1D porous sword-like MOF nanorods have a long length of around 1.3 µm. Due to the unique 2D/1D combined structure, the as-prepared FeNi LDH/MOF is directly used as electrocatalyst for the OER displays enhanced OER electrocatalytic performance with a low overpotential of 272 mV@100 mA cm–2, a small Tafel slope of 34.1 mV dec–1, high long-term durability. This work provides a new way to fabricate integrated ultrathin 2D nanosheets and MOFs as advanced catalysts for electrochemical energy conversion. 相似文献
7.
Jong-Sik Lim Young-Taek Lee Chul-Soo Kim Dal Ahn Sangwook Nam 《Microwave and Wireless Components Letters, IEEE》2002,12(12):479-481
The microstrip and coplanar waveguide transmission lines combined by a vertically periodic defected ground structure (VPDGS) are proposed. The slow-wave effect, equivalent circuit, and the performances are shown. As an application example, VPDGS is adopted in the matching networks of an amplifier for size-reduction. Two series microstrip lines in input and output matching networks of the amplifier are reduced to 38.5% and 44.4% of the original lengths, respectively, due to the increased slow-wave effects, while the amplifier performances are preserved. 相似文献
8.
9.
Summary We study integral functionals of the formF(u, )=
f(u)dx, defined foru C1(;R
k), R
n
. The functionf is assumed to be polyconvex and to satisfy the inequalityf(A) c0¦(A)¦ for a suitable constant c0 > 0, where (A) is then-vector whose components are the determinants of all minors of thek×n matrixA. We prove thatF is lower semicontinuous onC
1(;R
k) with respect to the strong topology ofL
1(;R
k). Then we consider the relaxed functional , defined as the greatest lower semicontinuous functional onL
1(;R
k
) which is less than or equal toF on C1(;R
k). For everyu BV(;R
k) we prove that (u,)
f(u)dx+c0¦Dsu¦(), whereDu=u dx+Dsu is the Lebesgue decomposition of the Radon measureDu. Moreover, under suitable growth conditions onf, we show that (u,)=
f(u)dx for everyu W1,p(;R
k), withp min{n,k}. We prove also that the functional (u, ) can not be represented by an inte- gral for an arbitrary functionu BVloc(R
n;R
k). In fact, two examples show that, in general, the set function (u, ) is not subadditive whenu BVloc(R
n;R
k), even ifu W
loc
1,p
(R
n;R
k) for everyp < min{n,k}. Finally, we examine in detail the properties of the functionsu BV(;R
k) such that (u, )=
f(u)dx, particularly in the model casef(A)=¦(A)¦. 相似文献
10.