The Decay of Swirling Flows in a Type of Cross-Section-Varying Pipes

ＩｎｔｒｏｄｕｃｔｉｏｎＳｗｉｒｌｉｎｇｆｌｏｗ (ｏｒｓｐｉｒａｌｆｌｏｗ )ｉｓｗｉｄｅｌｙｕｓｅｄｉｎｉｎｄｕｓｔｒｙ ,ｅ.ｇ .ｉｎｊｅｔｔｅｃｈｎｏｌｏｇｙ ;ｃｏｍｂｕｓｔｉｏｎｔｅｃｈｎｏｌｏｇｙ ;ｃｙｃｌｏｎｅ/ｈｙｄｒｏｃｙｃｌｏｎｅｓｅｐａｒａｔｏｒｓ;ｐｎｅｕｍａｔｉｃｔｒａｎｓｐｏｒｔａｔｉｏｎｅｔｃ .Ｓｗｉｒｌｉｓｃｏｍｍｏｎｌｙｉｍｐａｒｔｅｄｔｏｆｌｏｗｓｅｎｔｅｒｉｎｇｆｕｒｎａｃｅｓａｎｄｃｏｍｂｕｓｔｏｒｓｉｎｏｒｄｅｒｔｏｅｎｈａｎｃｅｆｌａｍｅｓｔａｂｉｌｉｔｙａｎ…     

Absorption and Capture of Methane into Ionic Liquid

A reversible storage-release process switched by a temperature difference of 10℃around room temperature can be realized. This fast, recyclable, energy efficient, low cost and green system within a wide range of temperature and pressure is reported here for the first time. The system is believed to open up a new route for the storage and homogeneous utilization of methane.     

Biological applications of scanning electrochemical microscopy: chemical imaging of single living cells and beyond

Recent applications of scanning electrochemical microscopy (SECM) to studies of single biological cells are reviewed. This scanning probe microscopic technique allows the imaging of an individual cell on the basis of not only its surface topography but also such cellular activities as photosynthesis, respiration, electron transfer, single vesicular exocytosis and membrane transport. The operational principles of SECM are also introduced in the context of these biological applications. Recent progress in techniques for high-resolution SECM imaging are also reviewed. Future directions, such as single-channel detection by SECM, high-resolution imaging with nanometer-sized probes, and combined SECM techniques for multidimensional imaging are also discussed.     

阴离子Gemini表面活性剂和阳离子传统表面活性剂混合体系双水相中囊泡形貌的转变

通过电子显微镜观察了阴离子gemini表面活性剂C₁₁- p-PhCNa和阳离子传统表面活性剂DTAB混合体系双水相中囊泡形貌随体系组成和浓度的转变。结果表明,双水相较浓的一相中形成了多层囊泡,囊泡的大小和壁厚随相的组成和浓度而改变,两组分等电荷混合有利于形成较大且壁较厚的囊泡。分析表明, gemini表面活性剂在聚集体中采取的反式构象可能是其容易形成厚壁多层囊泡的重要原因,C₁₁- p-PhCNa联接链上的苯氧基与DTA⁺之间的p-阳离子相互作用以及两组分相反电性头基之间的静电吸引使囊泡壁的多层结构更加稳定。     

Actively mode-locked dual-wavelength fiber laser with close wavelength spacing using a fiber Bragg grating

A simple actively mode-locked fiber ring laser is proposed and successfully demonstrated to generate dual-wavelength picosecond pulses with close wavelength spacing using one Bragg grating in standard single-mode fiber. The proposed laser can be made to operate in stable dual-wavelength at room temperature, due to the birefringence characteristic of the FBG induced by transverse strain. Transverse strain loading on the FBG allows the wavelength spacing to be controlled. Generation of stable dual-wavelength pulses with a pulsewidth of 212–234 ps and a tunable wavelength separation from 0.2 to 0.44 nm at a pulse rate of 1.05 GHz was demonstrated.     

Results of L-[1-13C]phenylalanine breath test with air isotope ratio mass spectrometry can reflect the activity of phenylalanine hydroxylase in cirrhotic rat liver

The L-[1-13C]phenylalanine breath test (PheBT) could potentially advance the evaluation of hepatocyte function and liver functional reserve. However, because the factors influencing PheBT results have not been clarified, the clinical application of the test has been limited. This study investigated the relationship between the parameters of PheBT, performed with air isotope ratio mass spectrometry, and the activity of phenylalanine hydroxylase (PAH), the phenylalanine metabolism rate-limiting enzyme, in rat liver, and proposes valid parameters for the assessment of liver function. Chronic injury to the liver was induced by the administration of CCl4 to male Sprague-Dawley rats for either 8 or 12 weeks. Livers from rats in the two cirrhotic groups were discolored, enlarged and roughly textured, with cells filled with fat granules of various sizes, pseudolobuli formations, and regenerated tubercles. Of the 12 parameters tested, only the unit liver weight (LW) breath test parameters, including the maximum abundance of 13C in breath (13Cmax/LW), 13C abundance in breaths 2 and 7 min after administration of L-[1-(13)C]phenylalanine (13C-phe) (13C2/LW and 13C7/LW), cumulative 13C excretion 10 and 30 min after 13C-phe administration (AUC10/LW and AUC30/LW), and the 13C excretion rate constant (PheBT-k/LW) were significantly affected in the chronic liver injury groups. There was no significant difference in the total PAH activity in liver among the three groups, but there was significant difference in unit LW PAH activity. Total PAH activity in the liver was significantly correlated with 13Cmax, 13C2, 13C7, AUC10, AUC30 and PheBT-k, while the unit LW PAH activity was significantly correlated with 13Cmax/LW, 13C2/LW, 13C7/LW, AUC10/LW, AUC30/LW and PheBT-k/LW. PheBT-k/LW was also correlated with biochemical indices that are used to assess liver function. The present findings indicate that the PheBT results based on air isotope ratio mass spectrometry can quantitatively reflect the change in total PAH activity in the livers of chronically injured rats. PheBT-k and PheBT-k/LW are the most sensitive among the test parameters, and can be used to assess liver functional reserve and hepatocyte damage at the molecular level.     

喹唑啉类衍生物的合成及抗菌活性研究进展

喹唑啉类化合物具有广泛的生物活性,在农药和医药领域受到了人们越来越多的关注.将不同药效团引入到喹唑啉骨架中,经结构修饰后能产生一系列具有抗菌活性的喹唑啉类化合物.本工作对近年来该类化合物的研究进行了综述,并对其发展前景进行了展望.     

The amperometric determination of indole-3-acetic acid based on CeCl<Subscript>3</Subscript>-DHP film modified gold electrode

An amperometric sensor for the determination of indole-3-acetic acid (IAA) based on the CeCl₃-DHP film modified gold electrode was developed. CeCl₃ was dissolved into water in the presence of dihexadecyl hydrogen phosphate (DHP). The IAA sensor was prepared via evaporating solvent of the CeCl₃-DHP dispersion on the gold electrode surface. The amperometric response of IAA on the CeCl₃-DHP film modified gold electrode was investigated. The experimental results indicate that the passivation of the electrode due to the adsorption of the oxidation product of IAA decreases significantly at the CeCl₃-DHP film modified gold electrode, in contrast to that at the bare and the DHP modified gold electrode. The experimental parameters were optimized and an electrochemical method for the determination of IAA was established. The oxidation peak current is linearly with the concentration of IAA from 1 × 10⁻⁷ to 2 × 10⁻⁵ mol l⁻¹ and the detection limit is 3 × 10⁻⁸ mol l⁻¹. The relative standard deviation of eight measurements is 3.2% for 5 × 10⁻⁷ mol l⁻¹ IAA. The IAA in plant leaves were extracted and determined by the IAA sensor.     

Ba_3(PO_4)_2:Ce~(3+),Dy~(3+)荧光粉的组成与发光特性研究

在活性炭还原气氛下高温固相法合成了Ba3(PO4)2:Ce3+,Dy3+紫外发射荧光粉。XRD图谱表明,烧结温度为1100℃时保温处理3 h,样品为单相的Ba3(PO4)2型六方晶系结构。荧光光谱显示:单掺Ce3+样品中,Ce3+掺杂浓度为8%(摩尔分数)时样品的发光最强,发射峰的位置处在350 nm附近(Ce3+的2D→2F5/2和2D→2F7/2跃迁发射)。适量的Sr2+取代部分Ba2+离子,改变了基质晶格环境,使样品的发光强度得到提高且发射峰向长波方向红移。引入Dy3+作为敏化剂,样品发射峰红移到386 nm,亮度增强,主要是由于Dy3+和Ce3+之间发生了有效的能量传递过程。确定了Dy3+的最佳掺杂浓度为3%,发光强度提高了27%。     

Polyvinyl alcohol fibers with functional phosphonic acid group: synthesis and adsorption of uranyl (VI) ions in aqueous solutions

PVA functionalized with vinylphosphonic acid was prepared as a new adsorbent for uranyl (VI) adsorption from aqueous solutions. The vinylphosphonic acid was cografted onto PVA fibers by preirradiation grafting technique. The adsorbent were characterized by Fourier transform infrared spectroscopy and scanning electron microscopy. The adsorbent was observed to possess a fibrous structure and was bonded with phosphonic acid groups successfully. The adsorbent was used for the adsorption of low levels uranyl (VI) ions from aqueous solutions. The influence of analytical parameters including pH, adsorption time, amount of adsorbent, metal ion concentration, and temperature were investigated on the recovery of uranyl (VI) ion in aqueous solution. The maximum adsorption capacity (32.1 mg g^?1) and fast equilibrium time (30 min) were achieved at pH of 4.5 at room temperature. Thermodynamic parameters (ΔH° = 2.695 kJ mol^?1; ΔS° = 31.15 J mol^?1 K^?1; ΔG° = ?6.748 kJ mol^?1) show the adsorption of an exothermic process and spontaneous nature, respectively. The possible coordination mechanism was illustrated. Adsorption and desorption coexist in aqueous solutions and then the system becomes equilibrium.