Completely positive tensors in the complex field

In this paper, we introduce the complex completely positive tensor, which has a symmetric complex decomposition with all real and imaginary parts of the decomposition vectors being non-negative. Some properties of the complex completely positive tensor are given. A semidefinite algorithm is also proposed for checking whether a complex tensor is complex completely positive or not. If a tensor is not complex completely positive, a certificate for it can be obtained; if it is complex completely positive, a complex completely positive decomposition can be obtained.     

改性TiO2纳米球在可见光诱导抗菌中的应用

本研究以硫酸钛作为钛源,油酸为表面活性剂,尿素为氮源,采用简单有效的一步水热法,在180℃条件下反应6h制备了N掺杂的改性TiO2纳米球（N-TiO2）。N元素的成功引入,扩展了TiO2对光谱的响应范围,使其能够充分利用可见光产生活性氧（ROS）。在可见光照射下,这种N-TiO2纳米复合材料与原始的TiO2、商用的光催化剂德固赛P25-TiO2和Ag沉积的N-TiO2相比,在其周围产生透明的抑菌圈,而其余三种材料看不到明显的抑菌圈。这说明其对革兰氏阴性大肠杆菌具有明显的杀灭效果。     

2-甲基-3-(4-对甲氧基苯基)-5-(3-甲氧基苯基)异噁唑啉及其生物活性

采用1,3-偶极环加成反应合成了2-甲基-3-对甲氧基苯基-5-间甲氧基苯基异噁唑啉,分离了顺、反异构体,采用核磁共振氢谱分析表征了顺反异构体的谱图行为,对异构体的生物活性进行了测定,新杀菌剂2-甲基-3-对甲氧基苯基-5-间甲氧基苯基异噁唑啉对病菌的有效成分为反式结构,顺式体为无效成分.     

Identification of C21 Steroidal Glycosides from Gymnema sylvestre (Retz.) and Evaluation of Their Glucose Uptake Activities

Gymnema sylvestre (Retz.) Schult is a multi-purpose traditional medicine that has long been used for the treatment of various diseases. To discover the potential bioactive composition of G. sylvestre, a chemical investigation was thus performed. In this research, four new C₂₁ steroidal glycosides sylvepregosides A-D (1–4) were isolated along with four known compounds, gymnepregoside H (5), deacetylkidjoladinin (6), gymnepregoside G (7) and gymnepregoside I (8), from the ethyl acetate fraction of G. sylvestre. The structures of the new compounds were established by extensive 1D and 2D nuclear magnetic resonance (NMR) spectra with mass spectroscopy data. Compounds 1–6 promoted glucose uptake by the range of 1.10- to 2.37-fold, respectively. Compound 1 showed the most potent glucose uptake, with 1.37-fold enhancement. Further study showed that compounds 1 and 5 could promote GLUT-4 fusion with the plasma membrane in L6 cells. The result attained in this study indicated that the separation and characterization of these compounds play an important role in the research and development of new anti-diabetic drugs and pharmaceutical industry.     

Effect of Si doping on near-infrared emission and energy transfer of Bismuth in silicate glasses

We have studied the effects of Si doping on the near infrared (NIR) luminescence observed in low Bi doped ( 0.1 mol% ) glasses and the energy transfer from Yb³⁺ to Bi. The broadband near infrared can only be observed when Si is introduced in the Bi-doped glass. The origin of this fluorescence can be attributed to Bi ions at low valence. Efficient energy transfer from Yb³⁺ to Bi NIR active ions is achieved by co-doping of Si. There is an increment of about ~ 29 times of the emission intensity from Bi-related active center as the Yb³⁺ concentration varies from 0 to 2.0 mol% and the amount of Si is 0.05 mol% under 980 nm excitation. The possible mechanism of energy transfer from Yb³⁺ to Bi is also discussed.     

Optical and Short- wavelength Recording Properties of Ag_8In_( 14) Sb_( 55) Te_(23) Phase-change Films

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Four kinds of raising and lowering operators ofn-dimensional hydrogen atom and isotropic harmonic oscillator

The factorization of the radial Schrödinger equation ofn-dimensional (n ≥ 2) hydrogen atoms and isotropic harmonic oscillators was investigated and four kinds of raising and lowering operators were derived. The relation betweenn-dimensional (n ≥ 2) and one-dimensional hydrogen atoms and harmonic oscillators was discussed.     

Novel phthalazinone‐bearing tetrafunctional epoxy: Synthesis,characterization, and their toughening application for TGDDM system

A novel tetrafunctional epoxy (TEPZ) was synthesized by “one spot two steps” method, and the effects of solvents, reaction temperature, and mole ratios of reactants on the reaction conversion were systematically investigated. The results demonstrated that the solvents participating in the reaction were the most crucial factor for high conversions. After curing, TEPZ/4,4′‐diaminodiphenyl sulfone (DDS) system exhibited better thermal stability compared with famous N,N,N′,N′‐tetraglycidyl‐4,4′‐diaminodiphenyl methane (TGDDM)/DDS analog. When TEPZ is blended with TGDDM/DDS, the initial decomposition temperature of TGDDM/TEPZ/DDS hybrid elevated from 348°C to 362°C. The storage modulus and the glass transition temperature were sensitive to curing procedure and concentration of DDS. While the system consisted of 100 phr TGDDM, 30 phr TEPZ, and 40 phr DDS, the storage modulus and glass transition temperature increased significantly compared with those of TGDDM/DDS, and the impact strength increased by 31.6% simultaneously. Such enhancement could be ascribed to the structural feature of phthalazinone in TEPZ, which formed stable interpenetrating networks during thermal cure procedure.     

Daphniphyllum alkaloids with cytotoxic activity from Daphniphyllum angustifolium

A new Daphniphyllum alkaloid, daphnezomine W (1), together with four known ones, were isolated from the stems of Daphniphyllum angustifolium Hutch. Their structures were elucidated by spectroscopic methods and comparing with the literature data. Compound 1 was a new daphnezomine L-type alkaloid and exhibited moderate cytotoxic activity against Hela cell line with IC₅₀ of 16.0 μg/mL. A plausible biosynthetic pathway of 1 was also proposed.