s-半置换子群对有限群的p-超可解性的影响

群G的子群H称为半置换的,若对任意的K≤G,只要（｜H｜,｜K｜）=1,就有HK=KH．H称为s-半置换的,若对任意的p｜｜G｜,只要（p,｜H｜）=1,就有PH=HP,其中P∈Sylp（G）．本文研究Sylow子群的极大子群及极小子群的s-半置换性对有限群的p-超可解性的影响．     

The first chemical synthesis of boronic acid-modified DNA through a copper-free click reaction

The first chemical incorporation of the boronic acid group into DNA using a copper-free click reagent was reported. Compared with the PCR-based method, this approach allows for site-specific incorporation and synthesis on a larger scale.     

High-yield Synthesis of Branched Gold Nanocrystals by a Sodium Diphenylamine-4-Sulfonate Reduction Process in Polyethylene Glycol Aqueous Solution

For developing new excellent electrocatalysts toward methanol and oxygen, branched Au nanocrystals have been prepared in high yield by the reaction of HAuCl₄ and sodium diphenylamine‐4‐sulfonate in the presence of PEG (polyethylene glycol) at room temperature. When the amount of PEG was in the range of 1–3 mL, branched Au nanocrystals were all obtained, and the amounts of sodium diphenylamine‐4‐sulfonate and HAuCl₄ had no obvious effect on the morphology of gold nanocrystals. PEG molecules play an important role in the formation of branched gold nanocrystals. The nanocrystals were characterized by transmission electron microscopy (TEM), selected area electron diffraction, high‐resolution transmission electron microscopy (HRTEM) and UV‐Vis absorption spectrum. HRTEM research suggests that the tips of gold nanocrystals grow selectively in the [111] directions. The UV‐Vis absorption spectrum displays two‐separated surface plasmon resonance peaks.     

Arylboronic Acid Chemistry under Electrospray Conditions

Boronic acids are important in the organic and biological arenas. Thus, their identification and characterization are important. ESI‐MS is a well‐known tool for such uses. Herein we report a systematic analysis of the chemical behavior of arylboronic acids under ESI‐MS conditions. Such information will be very critical to understanding the gas‐phase chemistry of boronic acids in an ESI mass spectrometer ion source in general and the MS analysis of boronic acids and their macromolecular conjugates in particular.     

Electrical bistable properties of hybrid device based on SiO2 modified-ZnO nanoparticles embedded in poly-4-vinyl-phenol

An electrical bistable device was fabricated by using SiO₂ modified-ZnO nanoparticles (NPs) embedded in poly-vinyl-phenol (PVP) polymer as the charge storage medium. Compared to the reference devices with PVP or ZnO NPs embedded in PVP, the proposed device showed improved reproducible electrical bistability. The time maintenance for On/Off states reached 10⁴ s${10}^4\text{s}$, revealing the better environmental stability. The carrier transport mechanism was interpreted by the space-charge-limited-current (SCLC), thermionic emission (TE) and ohmic conduction models. The charge trapping and de-trapping process of ZnO NPs were described based on the energy-band diagram of the device.     

Facile synthesis of red- to near-infrared-emitting CdTexSe1−x alloyed quantum dots via a noninjection one-pot route

High-quality CdTeSe colloidal nanocrystals with gradient distribution of components, consisting of Te-rich inner cores and Se-rich outer shells, were synthesized in a “green” solvent paraffin via a noninjection one-pot approach with the use of cadmium oxide (CdO), elemental tellurium, and elemental selenium as Cd, Te, and Se sources, respectively. All of these reactants were loaded at room temperature. This features synthetic reproducibility and large-scale capability. The bandgap engineering of the obtained CdTeSe QDs can be conveniently realized through the variation of growth temperature. Red- to near-infrared-emitting (620-780 nm) QDs with nearly identical particle sizes can be obtained when the reaction temperature was changed from 180 to 280 °C with the fixation of precursor feed ratio at 5Cd-0.5Te-0.5Se. The as-prepared CdTeSe QDs exhibit PL QY as high as 53%. The resulting CdTeSe QDs were characterized by UV-vis and photoluminescence spectroscopy, powder X-ray diffraction, transmission electron microscopy, and inductively coupled plasma atomic emission spectroscopy.     

Theoretical investigation of rotationally inelastic collisions of CH2(ã) with helium

Rotationally inelastic collisions of the CH(2) molecule in its a?(1)A(1) electronic state have been investigated. We have determined a potential energy surface (PES) for the interaction of rigid CH(2)(a?), frozen at its equilibrium geometry, with a helium atom, using a coupled-cluster method that includes all single and double excitations, as well as perturbative contributions of connected triple excitations [RSSCD(T)]. The PES is quite anisotropic, due to lack of electron density in the unoccupied CH(2) non-bonding orbital perpendicular to the molecular plane. Quantum scattering calculations have been carried out to compute state-to-state rotational energy transfer and elastic depolarization cross sections at collision energies up to 2400 cm(-1). These cross sections were thermally averaged to derive room-temperature rate constants. The total removal and elastic depolarization rate constants for the ortho k(a) = 1 levels agree well with recent experimental measurements by Hall, Sears, and their co-workers. We observe a strong even-odd alternation in the magnitude of the total rate constants which we attribute to the asymmetry splitting of the k(a) = 1 levels.     

铽、镝-3-噻吩乙酸二元、三元配合物的合成及表征

合成了四种新型的铽、镝的二元、三元配合物.通过元素分析、EDTA配位滴定分析表明其通式为RETh3·2H2O,RETh3phen(RE=Dy,Tb;Th=3-噻吩乙酸根;phen=1,10邻菲啰啉);对配合物进行了紫外光谱、红外光谱、荧光光谱、热重分析.结果表明,二元配合物在100℃左右失去结晶水,三元配合物具有较好的稳定性;在TbTh3phen中,3-噻吩乙酸和邻菲啰罗啉能很好地将能量传递给Tb3+离子,Tb3+离子546nm绿色荧光发射峰最强.     

Synthesis and drug-loading properties of folic acid-modified superparamagnetic Fe3O4 hollow microsphere core/mesoporous SiO2 shell composite particles

Magnetic nanoparticles with immobilized metal ligands were prepared for the separation of antibody fragments. First, iron oxide nanoparticles were produced in a solvothermal synthesis using triethylene glycol as solvent and iron(III) acetylacetonate as organic precursor. Via functionalization of the particles with priorly reacted 3-glycidoxypropyltrimethoxysilane and N α,N α-bis(carboxymethyl)-l-lysine (NTA), and charging with Ni²⁺, magnetic affinity adsorbents were obtained. The particles were applied to separate a His-tagged antibody fragment from a heterogeneous protein mixture of a microbial cultivation supernatant. Binding properties and specificity for purification of the target product ABF D1.3 scFv were optimized regarding the GNTA concentration and were found superior as compared to commercially available systems. A molar ratio of 1:2 Fe₂O₃:GNTA was most beneficial for the specific purification of the antibody fragment.     

Unsymmetrical N-Heterocyclic Carbene: 1-Isopropyl-3-benzylimidazol-2-ylidene as Catalyst for Ring-Opening Polymerization of ϵ-Caprolactone

An unsymmetrical N-heterocyclic carbene, namely 1-isopropyl-3-benzylimidazol-2-ylidene, is a highly active catalyst for ring-opening polymerization of ?-caprolactone (CL) to give polycaprolactone (PCL) with number average molecular weight (Mn) as high as 2.66 × 10⁴ at 0°C in 100 min in tetrahydrofuran (THF). The effects of monomer/initiator molar ratio ([M]/[I]), catalyst/initiator molar ratio ([C]/[I]), monomer concentration, as well as polymerization temperature and time have been investigated. The kinetic studies of CL polymerization have indicated that the polymerization rate is first-order with respect to both monomer and catalyst concentrations. The apparent activation energy amounts to 56.04 kJ/mol. The proposed mechanism is a monomer-activated process.