Stability and phase transition of localized modes in Bose–Einstein condensates with both two- and three-body interactions

We investigate the stability and phase transition of localized modes in Bose–Einstein Condensates (BECs) in an optical lattice with the discrete nonlinear Schrödinger model by considering both two- and three-body interactions. We find that there are three types of localized modes, bright discrete breather (DB), discrete kink (DK), and multi-breather (MUB). Moreover, both two- and three-body on-site repulsive interactions can stabilize DB, while on-site attractive three-body interactions destabilize it. There is a critical value for the three-body interaction with which both DK and MUB become the most stable ones. We give analytically the energy thresholds for the destabilization of localized states and find that they are unstable (stable) when the total energy of the system is higher (lower) than the thresholds. The stability and dynamics characters of DB and MUB are general for extended lattice systems. Our result is useful for the blocking, filtering, and transfer of the norm in nonlinear lattices for BECs with both two- and three-body interactions.     

The Synthesis and Reactivity of Alkylaminomethylene-Diphosphonates

Abstract

A accessible method for the synthesis of various alkylaminomethylenediphos-phonates is presented. The performed Vilsmeier reagents 2 (RCONR1R²/POCl₃) react with diethyl phosphite 1 to give the products 1 in good yield.     

Synthesis and electrochemical performance of sulfur–carbon composite cathode for lithium–sulfur batteries

In this paper, porous carbon was synthesized by an activation method, with phenolic resin as carbon source and nanometer calcium carbonate as activating agent. Sulfur–porous carbon composite material was prepared by thermally treating a mixture of sublimed sulfur and porous carbon. Morphology and electrochemical performance of the carbon and sulfur–carbon composite cathode were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammetry (CV), electrochemical impedance spectra (EIS), and galvanostatic charge–discharge test. The composite containing 39 wt.% sulfur obtained an initial discharge capacity of about 1,130 mA?h g^?1 under the current density of 80 mA?g^?1 and presented a long electrochemical stability up to 100 cycles.     

两个基于苯并咪唑席夫碱的镍(Ⅱ)配合物的合成、晶体结构和抑菌活性

在甲醇体系中,分别将苯并咪唑席夫碱HL¹和HL²与高氯酸镍进行配位反应得到2个结构类似的镍配合物[Ni（L¹）₂]·2H₂O（1）和[Ni（L²）₂]·2H₂O（2）（HL¹=N-（benzimidazol-2-ylethyl）-5-chlorosalicylideneimine,HL²=N-（Benzimidazol-2-ylethyl）-5-bromosalicyli-denei-mine）,并用元素分析、红外光谱、紫外-可见光谱和单晶X射线衍射对其结构进行了表征。结构分析表明：两个配合物均属于单斜晶系,C2/c空间群,Ni（Ⅱ）与来自2个席夫碱配体的4个氮原子和2个氧原子配位,形成八面体结构。配合物中的氢键将配合物1和配合物2分别连接成二维和三维网络结构。选取金黄色葡萄球菌和大肠杆菌作为菌种,研究了2个席夫碱配体和2个配合物的抑菌能力。     

EDTA辅助水热法制备性能优异的棒状LiFePO4/C材料

以乙二胺四乙酸为配位剂采用水热法制备了棒状LiFePO₄/C材料。采用X射线衍射、扫描电镜、透射电镜、循环伏安、交流阻抗和恒电流充放电测试等对材料进行表征。结果表明:乙二胺四乙酸对材料的形貌和电性能均有很大影响。通过加入乙二胺四乙酸, 材料的形貌由不规则的颗粒变为棒状的颗粒且颗粒的厚度由140~200 nm减少至40~90 nm, 材料的表面包覆约3.5 nm的均匀碳层, 且该材料极化较小且界面阻抗较低。0.1C放电比容量为167 mAh·g^-1(接近理论容量170 mAh·g^-1)。     

SiO2/炭泡沫和SiC/炭泡沫复合材料的制备及表征

对炭泡沫为支撑骨架的氧化硅气凝胶(SiO₂/炭泡沫)和碳化硅(SiC/炭泡沫)复合材料分别采用XRD、SEM、激光导热仪、万能力学试验机进行物相、微观结构、热学及力学性能方面的表征.结果表明:所制备的SiO₂/炭泡沫与原炭泡沫相比,具备更高的抗压强度(14.95 MPa)和更低的室温热导率(0.44 W·m^-1·K^-1).SiC/炭泡沫材料则保持了较高的抗压强度值(14.66 MPa),其在 1 200 ℃下具备极低的高温热导率(2.18W·m^-1·K^-1).热重分析表明,SiC/炭泡沫在氧化氛围中到610 ℃才发生质量的损失,而内部炭发生完全烧蚀的温度高达844 ℃,这表明该材料的抗氧化性能远好于纯的炭泡沫材料.     

New Strategy for the Synthesis of Phosphonyl Pyrazoles

Phosphonyl hydrazones react with DMF/POC1₃ to afford 3-phosphonyl pyrazoles. Phosphonyl methylene hydrazones react with DMF/POC1₃ to provide 4-phosphonyl pyrazoles. 5-Phosphonyl pyrazoles are obtained from the reaction of phosphonyl chlorovinylaldehydes with phenylhydrazine.     

Immobilization and sustained release of cefalexin on MCF nano-mesoporous material

Abstract

Mesocellular foams (MCF) silica nanometer mesoporous molecular sieve was successfully synthesized by hydrothermal route. This method used poly(ethylene glycol)-block-poly(propyl glycol)-block-poly(ethylene glycol) as template, tetraethyl orthosilicate as silica source and 1, 3, 5-trimethylbenzene as pore-expanding agent to prepare nano mesoporous MCF in acidic medium. The MCF mesoporous material was characterized by powder X-ray diffraction (XRD), infrared (IR) spectroscopy, low temperature nitrogen adsorption-desorption at 77?K, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The effects of pH, temperature, adsorbent dosage, cefalexin dosage and contact time on the immobilization of cefalexin were studied. Under the optimized conditions, MCF has the best effect on the drug immobilization. The maximum immobilization amount of cefalexin in MCF nano-mesoporous material is 498.8?mg/g. The behavior of adsorption of cefalexin by MCF belongs to multilayer heterogeneous adsorption, which accords with the Freundlich adsorption isotherm. In the adsorption process, all the ΔH⁰, ΔS⁰ and Gibbs free energy change ΔG⁰ are less than zero, indicating that the adsorption process is spontaneous, exothermic entropy decreasing reaction at ordinary temperature. Kinetic investigation showed that the adsorption process of cefalexin on MCF belongs to the pseudo-second-order kinetic process. The release laws of composite material cephalexin-MCF in the simulated body fluid, gastric and intestinal fluid were investigated, respectively. The maximum cumulative release rate in simulated body fluid was 99.4% at 18?h. The maximum cumulative release rate in the simulated gastric juice was 48.7% at 6?h and in the simulated intestinal fluid the maximum cumulative release rate of 61.9% was achieved at 8?h. These release processes satisfy the zero-order ordered kinetic process.     

基于核酸分子杂交的免疫芯片抗体固定新方法

基于核酸分子杂交原理构建了一种新型抗体固定方法.先将抗体与寡核苷酸单链交联,再将两者的复合物与固相载体表面上的互补寡核苷酸链结合,从而将抗体固定到载体的表面.在磁珠表面对该固定方法进行实验,证明了方法的可行性.以本方法构建了针对转基因Bt Cry1Ac蛋白的免疫芯片,用Cy3标记二抗对其探针固定效果进行分析,并且在芯片上对Bt Cry1 Ac蛋白进行梯度浓度检测试验.结果表明,以本方法构建的抗体芯片,探针分布具有良好的特异性;探针层分布均匀,非特异吸附小;检测灵敏度达到0.01 ～ 0.05 μg/L;此外,通过杂交核酸双链的解离成功实现了芯片的再生,有助于解决传统抗体固定方法中芯片不可再生的问题.     

基于滤纸微孔板的酶联免疫吸附测定方法研究

用光刻法在普通定量滤纸上制作出了疏水图案,得到了滤纸微孔板。将表面修饰后的SiO2微球负载在滤纸表面,以提高滤纸纤维吸附蛋白质的能力,基于此建立了以间接酶联免疫吸附法测定羊抗兔免疫球蛋白的方法。以酶标兔抗羊IgG为例,负载SiO2微球后,滤纸微孔板吸附该蛋白质的量提高了20%～700%;将SiO2负载法应用于羊抗兔IgG的检测时,可使信号增强20%～150%。在本实验条件下,测定羊抗兔IgG的线性范围为3×10-12～3×10-8mmol/孔。本方法使生物免疫试剂消耗量减少至3～5μL/孔、检测时间降至20 min/板、滤纸微孔板制作成本可低至约每板1.1美元,为研制准确、快速和低成本的疾病检测设备提供了新的思路和可能性。