二维衍射光栅在彩虹全息中的应用

提出了将正交位相光栅和扇出光栅应用于制作彩虹全息图的方法,分析了正交位相光栅产生的多重全息像的位置和强度分布,给出制作扇出光栅的一种实用方法,并给出了实验结果。     

The distribution of the generic recursively enumerable degrees

Summary In this paper we investigate problems about densities ofe-generic,s-generic andp-generic degrees. We, in particular, show that allp-generic degrees are non-branching, which answers an open question by Jockusch who asked: whether alls-generic degrees are non-branching and refutes a conjecture of Ingrassia; the set of degrees containing r.e.p-generic sets is the same as the set of r.e. degrees containing an r.e. non-autoreducible set.This research was supported by a grant of the Stiftung Volkswagenwerk     

Synthesis of ordered mesoporous carbon monoliths with bicontinuous cubic pore structure of Ia3d symmetry

Large-diameter-sized mesoporous carbon monoliths with bicontinuous cubic structure of Ia3d symmetry have been synthesized by using mesoporous silica monoliths as hard templates; such carbon monoliths show potential application of advanced electrodes and electrochemical double layer capacitors.     

Ganoderic acid Sz, a new lanostanoid from the mushroom Ganoderma lucidum

A new lanostanoid, ganoderic acid SZ (1), isolated from a lipophilic extract of the fruiting body of Ganoderma lucidum, is a geometric Z-isomer of the known ganoderic acid S (2). The structure of ganoderic SZ (1) was deduced mainly by 1D and 2D NMR studies. During the course of this study, 12 known lanostanoids have also been isolated and characterized.     

Visible light‐emitting diode‐sensitive thioxanthone derivatives used in versatile photoinitiating systems for photopolymerizations

Novel thioxanthone (TX) derivatives are used as versatile photoinitiators upon visible light‐emitting diode (LED; e.g., 405, 425, and 450 nm) exposure. The mechanisms for the photochemical generation of reactive species (i.e., cations and free radicals) produced from photoinitiating systems based on the photoinitiator and an iodonium salt, tris(trimethylsilyl)silane, or an amine, were studied by UV–vis spectroscopy, fluorescence, cyclic voltammetry, steady‐state photolysis, and electron spin resonance spin‐trapping techniques. The reactive species are particularly efficient for cationic, free radical, hybrid, and thiol‐ene photopolymerizations upon LED exposure. The optimized photoinitiating systems exhibit higher efficiency than those of reference systems (i.e., isopropyl TX‐based photoinitiating systems), especially in the visible range. According to their beneficial features, these photoinitiating systems have considerable potential in photocuring applications. © 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2017 , 55, 4037–4045     

Ar离子辅助沉积对含氢类金刚石薄膜结构影响的计算机模拟

选C₂分子和一定量的H原子作为沉积源,Ar离子作为辅助沉积粒子,采用分子动力学(MD)方法模拟研究离子束辅助沉积(IBAD)生长类金刚石(DLC)膜的物理过程.给定Ar的入射能量并改变Ar的到达比(Ar/C),研究辅助沉积对DLC膜结构的影响;重点讨论Ar辅助沉积引起表面原子的瞬间活性变化对薄膜结构产生的影响.结果表明,由于Ar离子轰击引起的能量和动量的传递,增加了合成薄膜的SP³键含量,增大了合成薄膜的密度,加宽了沉积粒子和衬底的结合宽度,研究结果和实验观察一致,并从合成机理上给出一些定量解释.     

Controlled radical polymerization of N‐vinylcaprolactam mediated by xanthate or dithiocarbamate

Controlled radical polymerization of N‐vinylcaprolactam (NVCL) via reversible addition‐fragmentation chain transfer (RAFT) polymerization or macromolecular design via the interchange of xanthate (MADIX) was described, employing 2‐diphenylthiocarbamoylsulfanyl‐2‐methyl‐propionic acid (CTA1), ((O‐ethylxanthyl)methyl)benzene (CTA2) and (1‐(O‐ethylxanthyl)ethyl)benzene (CTA3) as chain transfer agents (CTA). It was found that all the CTAs led to controlled radical polymerization of NVCL, with the molecular weight increased along with the conversion of monomer and a relatively narrow molecular weight distribution could be obtained, as determined with matrix‐assisted laser desorption and ionization time‐of‐flight (MALDI‐TOF) and gel permeation chromatography (GPC), the polydispersity indices, as determined by MALDI‐TOF, were typically on the order of 1.24, but the polymerization did not proceed in a strictly living manner. The chain transfer ability of these CTAs was in the following order: CTA1 ≈ CTA2 < CTA3. MALTI‐TOF measurement showed that the major population of polymer retained the chain‐end functional group, but minor population deactivated by radical coupling. In preparation of the block copolymer of NVCL and vinyl acetate (VAc) by sequential polymerization, the sequence of monomer addition was important. Using VAc as the first monomer could lead to a block copolymer presenting a unimodal GPC trace and a narrow PDI index, and if NVCL was used as the first monomer, the polymerization was less well controlled. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 3756–3765, 2008     

Supramolecular fuzzy recognition leads to effective differentiation of similar molecules

The separation of structurally similar molecules remains a general challenge; here, we report that a roughly defined macromolecular nanocapsule can efficiently separate a variety of structurally similar mixtures. The nanocapsule is a core?shell amphiphilic macromolecule (CAM) hydrophobically derived from hyperbranched polyethylenimine with 2‐hexadecyloxymethyloxirane. It is found that with further chemical core engineering of the CAM, its guest selectivity can be radically enhanced, although specific host?guest interaction is absent or ignorable in the system. As a result, two groups of structurally similar guests such as fluorescein/tetrachlorofluorescein, and rose bengal/erythrosine B/eosin Y, can be well recognized by the CAMs. It is known that a complex (fuzzy) system is generally characterized by complexity and nonlinearity; thus core engineering of a CAM is possible to amplify the difference of the competitive guests and lead to effective guest differentiation, such a mechanism is called supramolecular fuzzy recognition (SFR). Our results demonstrate that with appropriate combination of various elementary interaction styles, SFR can lead to effective recognition of a wide spectrum of mixtures. Moreover, a SFR host can be roughly defined in structure and thus readily available. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Unimolecular micelle derived from hyperbranched polyethylenimine with well‐defined hybrid shell of poly(ethylene oxide) and polystyrene: A versatile nanocapsule

The synthesis and properties of a macromolecular nanocapsule derived from hyperbranched polyethylenimine (HPEI) with well‐defined hybrid shell of poly(ethylene oxide) monomethyl ether (mPEO) and polystyrene (PS) are described. HPEI is treated in sequence with 4‐glycidol‐2,2,6,6‐tetrametyl‐piperidin‐1‐oxyl, succinic anhydride, mPEO, leading to a HPEI derivative compatible with nitroxide‐mediated living radical polymerization of styrene, thus a macromolecular nanocapsule, HPEI@PEO/PS, is available with a well‐defined and tunable hybrid shell of PEO and PS. Within certain PEO/PS ratio, the nanocapsule is soluble in a number of organic solvents as well as in water. The nanocapsule exists as three layer onion‐like particle (HPEI@PS@PEO) in water, whereas in chloroform it exists as a hybrid shell particle (HPEI@PEO/PS), and the particles generally exist in the form of unimolecular micelle. In a biphasic water/chloroform mixture, the nanocapsule can transfer anionic, water‐soluble guest from an aqueous phase to the chloroform phase; while when dissolved in water, the nanocapsule can efficiently capture both ionic and apolar solutes. Release of the guest can occur under the stimulus of pH or the switch of medium. This is the first example of a unimolecular micelle that can simultaneously deliver both polar and apolar guests. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 681–691, 2010