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[en] Radioisotope microball tracer which was produced by new process is applicable to injection profiling in low injection rate wells. Five-parameter combo logging tools were developed, which enhance accuracy and reliability of log by integrating interpreting flowrates inside tubing, shut-in and flowing well temperatures and tracing results. Reliable impulse oxygen-activation logging tools and a tracer logging method with correlation arithmetic were developed to meet the need of profiling polymer injectors. These new techniques are widely used in injection profile logging at Daqing oilfield. (authors)
[en] Nitrogen-doped single-walled carbon nanohorns (N-SWCNHs) have been synthesized by a flowing nitrogen assisted arc discharge method at atmospheric pressure in a tubular reactor. X-ray diffraction and thermogravimetric analysis have revealed their high quality. Scanning electron microscopy and transmission electron microscopy examinations have shown that N-SWCNHs have typical spherical structure with a diameter of 40–80 nm. Oxidation treatment suggests the opening of cone-shaped caps of N-SWCNHs. The FT-IR and X-ray photoelectron spectroscopy analysis indicate that most of the nitrogen atoms are in N-6, N-5, and triple-bonded -CN bonding configuration present at the defect sites or the edges of graphene layers.
[en] This study explored a simple and fast method utilizing ultraviolet (UV) irradiation to synthesize CdTe/CdS/ZnS QDs in aqueous solution. Based on the reaction of photolysis and chemical deposition, the CdS and ZnS shell can be successively deposited around the thiol-capped CdTe cores through the interaction of Cd2+/Zn2+ and S2− produced by UV irradiation. The effect of the UV irradiation time, the ratios of thioglycolic acid (TGA)/Cd and TGA/Zn on the shell formation, shell stability, and the photoluminescence (PL) intensity of the QDs, was systematically investigated. Keeping the ratio of TGA/Cd, increasing UV irradiation time from 30 to 120 s, the blue-shift of the fluorescence emission peak position of CdTe/CdS QDs was observed. As the irradiation time increased continuously from 120 to 300 s, the red-shift of the emission peak position was observed. In the total irradiation time, the PL intensity of all the samples was enhanced. By applying 300 s irradiation on the samples, the emission peak was blue-shifted at a fixed TGA/Cd ratio of 1:1 and red-shifted at the ratios of 2:1, 4:1, 8:1, and 13:1. The PL intensity reached its highest value at the ratio of 2:1. The effect of TGA/Zn ratio on ZnS shell formation showed a similar progress. Under an optimum synthesized reaction condition, the particle sizes of CdTe core, CdTe/CdS core–shell and CdTe/CdS/ZnS core–shell–shell QDs were 2.6 nm, 3.4 nm, and 4.6 nm respectively. This study confirmed that with the core–shell–shell structure, CdTe/CdS/ZnS QDs had high anti-oxidability, photostability, and low toxicity. Therefore they can be further used in cell imaging efficiently. (paper)
[en] A novel quantum dots-based multifunctional nanovehicle (DOX-QD-PEG-FA) was designed for targeted drug delivery, fluorescent imaging, tracking, and cancer therapy, in which the GSH–CdTe quantum dots play a key role in imaging and drug delivery. To exert curative effects, the antineoplastic drug doxorubicin hydrochloride (DOX) was loaded on the GSH–CdTe quantum dots through a condensation reaction. Meanwhile, a polyethylene glycol (PEG) shell was introduced to wrap the DOX-QD, thus stabilizing the structure and preventing clearance and drug release during systemic circulation. To actively target cancer cells and prevent the nanovehicles from being absorbed by normal cells, the nanoparticles were further decorated with folic acid (FA), allowing them to target HeLa cells that express the FA receptor. The multifunctional DOX-QD-PEG-FA conjugates were simply prepared using the ‘one pot’ method. In vitro study demonstrated that this simple, multifunctional nanovehicle can deliver DOX to the targeted cancer cells and localize the nanoparticles. After reaching the tumor cells, the FA on the DOX-QD-PEG surface allowed folate receptor recognition and increased the drug concentration to realize a higher curative effect. This novel, multifunctional DOX-QD-PEG-FA system shows great potential for tumor imaging, targeting, and therapy. (papers)