Raman intensity enhancement of molecules adsorbed onto HfS flakes up to 200 layers.

Newly emerging two-dimensional transition metal dichalcogenide HfS2 has received considerable attention recently due to its ultrahigh photoresponsivity, well-balanced carrier mobility and an appropriate band gap which offer potential in electronic and optoelectronic devices. In this work, HfS2 flakes up to 200 layers with varying color contrasts are fabricated and transferred on a SiO2/Si substrate. The Raman intensities of HfS2 flakes and Raman intensities of molecules adsorbed on HfS2 flakes are quantitatively studied both theoretically and experimentally by considering an optical interference effect.

[Morphology and Spectral Properties Study of LaCeF3:Tb Microcrystalline].

LaCeF3:Tb microcrystalline was synthesized by microemulsion method, oleic acid-assisted solvothermal method, ultrasonic-assisted solvothermal method separately. LaCeF₃:Tb microcrystalline synthesized by ultrasonic-assisted solvothermal method is rarely reported. Using X-ray diffraction (XRD), scanning electron microscope (SEM), fluorescence spectroscopy (PL) method such as the crystal phase, morphology and luminescence properties of the samples have been characterized.

[The Different Phase, Morphology Controllable Synthesis and Luminescent Properties Investigation of NaYF⁴: Yb, Er].

Using sodium fluoride and rare earth nitrate as raw materials and sodium citrate as surfactant, micron grade NaYF4 upconversion luminescent materials were prepared by hydrothermal method. By X-ray diffraction(XRD), scanning electron microscope(SEM) and fluorescence spectrometer, the crystal phase, morphology and luminescent characteristics of the prepared samples were investigated. The results showed that the phase of the samples could generate a transition from cubic phase to hexagonal phase by adjusting the proportion (5, 6, 7, 8, 9, 11) of NaF/RE , and the X ray diffraction peaks for the cubic and hexagonal phase of samples exactly matched with those of the standard card of PDF# 77-2042 and PDF# 16-0334, respectively.

[The Synthesis, Luminescence and Energy Transmission of NaLa(MoO4) 2 : Eu3+/Tb3+/Tm3+ Materials].

A series of Eu3+ /Tb3+ /Tm3+ single/co-doped NaLa(MoO4)2 (NLM) phosphors have been synthesized by microemulsion-hydrothermal method. Phosphor crystal structure, morphology and luminescent properties were tested and studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectroscopy. The results show that the prepared samples are all tetragonal single crystals.

[Detection of Plasmodium falciparum by using magnetic nanoparticles separation-based quantitative real-time PCR assay].

Objective: To establish a magnetic nanoparticles separation-based quantitative real-time PCR (RT-PCR) assay for fast and accurate detection of Plasmodium falciparum and providing a technical support for improving the control and prevention of imported malaria.

Methods: According to the conserved sequences of the P. falciparum genome 18SrRNA, the species-specific primers and probe were designed and synthetized.

[Study of fast pretreatment method in detection of melamine in liquid milk using liquid chromatography and Raman spectroscopy].

The present paper proposed for the first time the flocculation-filtration method for separation of interfering substances in milk, such as fat. In this method only two steps were carried out. Firstly, aluminum chloride (PAC, Al2 (OH)nCl6-n,) is used to flocculate the milk; Secondly, water filter was used to filter the mixture.

[Color-tunable nano-material alpha-NaYF4 : Yb, Er, Tm prepared by microemulsion-hydrothermal method].

NaYF4 : Yb3+, Er3+, Tm3+ nanoparticles were prepared by microemulsion-hydrothermal method. Crystal phase, morphology and structure of the samples were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The luminescence properties were studied by up-conversional fluorescence spectroscopy.

[Influence of Bi3+ doping on properties of CaMoO4 : Eu3+ phosphors].

Europium doped CaMoO4 and bismuth co-doped CaMoO4 : Eu3+ phosphors were prepared via microemulsion-hydrothermal method. The structure, morphology and luminescence properties of samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and fluorescence spectroscopy, respectively. The XRD patterns of as-prepared samples were in agreement with the PDF # 29-0351 of CaMoO4, which indicated that the phosphor possessed tetragonal crystal structure.

[Research progress in Raman spectra and its test sample pretreatment].

It is generally accepted that Raman spectroscopy is an advanced method with simple operation, small amount of specimens needed as well as rapid on-line screening, detection and identification. However, in the technology of determination, sample preparation is also an significant factor during analysis process. It would affect the accuracy and precision of the results, and normally involved complicated procedure.

An immunosensor based on magnetic relaxation switch and polystyrene microparticle-induced immune multivalency enrichment system for the detection of Pantoea stewartii subsp. Stewartii.

A rapid, sensitive, and simple immunosensor has been developed for the detection of Pantoea stewartii subsp. Stewartii (Pss). This immunosensor combines magnetic relaxation switch (MRS) assay with polystyrene microparticle-induced immune multivalency enrichment system.

Immunosensor based on magnetic relaxation switch and biotin-streptavidin system for the detection of Kanamycin in milk.

A rapid, sensitive, and simple immunosensor was developed for the detection of Kanamycin (KM) in milk. This immunosensor is based on magnetic relaxation switch (MRS) assay and biotin-streptavidin system (B-SA system). The target analyte (KM) competed with those on the surface of the superparamagnetic iron oxide (SPIO) nanoparticles and hence affected the formation of SPIO aggregates.

[Quality analysis of olive oil and quantification detection of adulteration in olive oil by near-infrared spectrometry and chemometrics].

Discriminant analysis was used to classify 20 olive oil samples based on their near-infrared (NIR) spectra. The samples were successfully classified into two categories which are consistent with extra virgin olive oil and ordinary olive oil defined in the products. The NIR spectra of olive-oil mixtures containing colza oil, corn oil, peanut oil, camellia oil, sunflower oil, and poppy seed oil were collected, respectively.

Rapid authentication of olive oil adulteration by Raman spectrometry.

The authentication of olive oil and its adulteration with lower priced oils are still serious problems in the olive oil industry. In this study, a method based on the intensity ratio of the Raman spectroscopy vibration bands, especially on the intensity ratio of the cis ( ==C-H) and cis (C=C) bonds normalized by the band at 1441 cm(-1) (CH(2)), was established to authenticate genuine/fake olive oil. These intensity ratios of the vibration bands given in the form of a two-dimensional chart allow first the discrimination between the various grades of olive oil and the seed oils and then the detection of olive oil fraud by the line of y = 0.

A rapid and facile method for hydrothermal synthesis of CdTe nanocrystals under mild conditions.

By using a novel procedure, a new kind of water-soluble CdTe nanocrystals (NCs) is synthesized in aqueous solutions at the temperature of 100 degrees C. In this procedure, tripeptide thiol glutathione was used as stabilizing agent, CdTe NCs with controllable photoluminescence wavelength from 500 nm to 680 nm were prepared within two hours. Compared with CdTe NCs prepared with thiohydracrylic acid as stabilizing agent, as-prepared NCs show much narrower photoluminescence FWHM, more symmetrical emission peak and higher photoluminescence quantum yield.