含氨酯基的壳聚糖衍生物的胆甾液晶螺旋性质

用圆偏振光二向色性谱法研究了3种含氨酯基的壳聚糖衍生物的胆甾液晶螺旋性质.结果表明,3种衍生物的质量分数为65%的氯仿溶液都呈现胆甾液晶相.此外,CD谱观察结果显示侧基结构对其胆甾螺旋方向有明显的影响

N-乙基壳聚糖的单晶

用光固化法制备N 乙基壳聚糖/聚丙烯酸复合膜.在复合膜中观察到单晶和悬挂着单晶片的微纤.单晶的长和宽约为300～400nm,比常见的晶粒尺寸小得多.与通常单晶的极稀溶液制备条件不同,该单晶是在复合膜中形成的.水的诱导结晶作用和体系的高浓度形成了一种几乎是无限缓慢的结晶条件,单晶正是由于这样条件才能得以形成

热塑性甲壳素衍生物N,O-苄基壳聚糖的合成及表征

Chitin derivatives are difficult to be melten because of their very strong inter-molecular and intra-molecular hydrogen bonds. In this paper, N,O-benzyl chitosan was synthesized by means of phase-transfer method. The total degree of substitution for this derivative was 0 8 as determined with 1H NMR and the degree of substitution on nitrogen was 0 3 as determined with elemental analysis. This is a thermoplastic chitin derivative. Its melting point was 470 K as measured with DSC. A viscous isotropic melt occurred at the temperatures between the melting point and the decomposition temperature(513 K) while N,O-benzyl chitosan was heated on a hot stage. DSC results agreed with the results of microscopy observation. The benzyl group can not form hydrogen bonds. It is also non-polar and has larger volume. These factors weaken the interactions between chitosan chains, and therefore decrease the melting point, which was lower than the decomposition temperature. As a result, N,O-benzyl chitosan was able to melt

甲壳素类液晶高分子的研究Ⅶ.N,O-苄基壳聚糖的胆甾螺旋行为

N ,O-苄基壳聚糖在浓溶液中形成胆甾液晶相 .用圆偏光二向色性谱 (CD)研究了这一聚合物的螺旋行为 ,主要包括螺距和螺旋方向 .浓度越高 ,螺距P越大 ,意味着胆甾相的扭转力随浓度增加而减弱 .CD谱图上观测到两类吸收 ,即在 5 70nm附近较宽但较强的吸收和 330nm附近较尖但较弱的吸收 .前者归属于胆甾相层片的超分子螺旋构象 ,而后者可以归属于分子链的螺旋构象 .改变浓度或溶剂性质时这两个层次的构象都会发生符号的变化 .提高浓度 (固定二氧六环为溶剂 )时两种螺旋结构先后发生反转 .以氯仿为溶剂 (固定浓度为 6 5 % )时两种螺旋结构均为左旋 (正Cotton效应 ) ,但二氧六环和四氢呋喃为溶剂时均变为右旋 (负Cotton效应 ) .溶剂的影响可能与溶剂和高分子间形成氢键的能力有

嗜虫耶尔森氏菌HlyA及HasA外分泌表达系统的构建

【目的】构建一株具备外分泌蛋白功能的工程菌,解决杀虫毒素无法由胞内分泌至胞外,无法直接作用于虫体等问题,为松墨天牛防治提供新思路。【方法】本研究先测定从松墨天牛肠道及其生境中分离出的嗜虫耶尔森氏菌(CSLH88)的生长特性及抗性,进而对其进行分子改造。构建HlyA (pGHKW2)以及HasA (pGHKW4)外分泌表达载体,利用电穿孔法将其转入CSLH88菌株,获得能够表达绿色荧光蛋白的工程菌。利用稀释涂板及荧光体式镜检测技术对两个质粒进行遗传稳定性检测,并采用SDS-PAGE及Western blotting技术验证蛋白外分泌功能。【结果】CSLH88菌株培养2–4 h能够进入对数生长期,并对卡那霉素(Kan)敏感。成功构建了含有Kan抗性基因的pGHKW2(GenBank:MK562405)和pGHKW4(GenBank:MK562404)两个外分泌表达载体的CSLH88工程菌株。其中,发现pGHKW4质粒更加适合在嗜虫耶尔森氏菌中稳定遗传。SDS-PAGE及Western blotting检测结果表明HlyA系统无法在CSLH88菌株中将目的蛋白分泌到胞外,而HasA系统则可以有效地发挥外分泌表达功能。【结论】通过对HlyA及HasA两个外分泌表达系统进行研究,从中筛选出HasA型血红素转运系统作为CSLH88菌株的外分泌表达系统,为后续外分泌杀虫毒素蛋白菌株构建以及CSLH88菌株的致病性研究奠定基础。国家重点研发计划课题(2017YFD0600105);;\n国家自然科学基金(31601905);;\n福建省科技厅自然科学基金(2016J01097);;\n福建省科技计划项目(2018N5002);;\n福建农林大学科研基金(xjq201614);福建农林大学林学院林学高峰学科项目(71201800720,71201800753,71201800779);;\n福建省大学生创新创业训练计划项目(201810389102);;\n福建省林业科学研究项目[Minlinke(2017)03]~

视网膜动脉阻塞：“视网膜卒中”的认识与挑战 Retinal Artery Occlusion: Knowledge and Challenge of “Retinal Stroke”

视网膜动脉阻塞是临床上导致急性无痛性单眼视力丧失的主要疾病，由于发病机制和危险因素与缺血性卒中相似，被视为“视网膜卒中”。但作为一种特殊类型的卒中，“视网膜卒中”的临床管理仍存在较高的不确定性和争议。本文对“视网膜卒中”的定义演变、就诊科室、识别和评估、检查、治疗和二级预防等方面进行综述，以期为临床医师全面认识和系统规范诊治“视网膜卒中”提供依据。 Abstract: Retinal artery occlusion is the main cause of acute painless monocular vision loss, and its pathogenesis and risk factors are similar to ischemic stroke, so it is named as “retinal stroke”. However, as a special type of stroke, the clinical management of “retinal stroke” is still highly uncertain and controversial. This article reviewed the literatures on “retinal stroke”, and introduced the definition, department for medical treatment, recognition and evaluation, examination, treatment and secondary prevention of “retinal stroke”, in order to help clinicians better understand and standardize the diagnosis and treatment of retinal stroke

Development of a Simulation System for FCCU Fractionator

在综合考虑了塔板效率、物料、能量、组分衡算方程和相平衡以及塔板水力学方程的基础上,建立了包括附属设备在内的催化裂化分馏塔严格机理动态模型,并采用房室法、虚拟组分法将模型合理简化,在简化后的动态模型之上,结合控制器方程,在XD-APC平台上组态,创建了催化裂化分馏塔全塔控制仿真系统,通过图形组态,以逼真的虚拟环境来完全模仿实际工业装置的计算机控制过程.全塔仿真系统的建立,对催化裂化全套装置进行仿真控制和全局优化奠定了基础。Based on the equations of mass,energy,composition balance,phase equilibrium and plate hydraulics as well as tower efficiency calculation,a general dynamic mechanism model is developed for rigorous dynamic simulations of the Fluidized Catalytic Cracking Unit(FC- CU)fracfionator.To simplify the models,the compartment method is adopted and the products of the catalytic crocking unit are described as pseudo components by generally accepted practice.Then the simulation system of FCCU fractionator is successfully developed on the XD-APC, according to the simplified dynamic model above combined with the related controller equations.The vivid interfaces of the system are designed elaborately to mimic the real process,providing an integrated engineering environment to the operators.The usefulness and validation of the system is illustrated on a simulated distillation column with good performance,presenting opportunities for the future establishment of suitable integrated advanced control and on-line closed loop optimization structure of the whole FCCU system

Model Study on the Tidal Regime and Pollutant Transport in the Fuqing Bay

运用一个含动边界的二维河口海岸动力模型模拟了福清湾潮汐潮流的基本特征,模拟结果与实测数据吻合较好.在此基础上估算了福清湾涨落潮流历时,分别为6 H 19 MIn 2 S和6 H 3 MIn 48 S;大小潮周期的纳潮量,分别为10.94x107和4.47x107M3;福清湾的半交换和80%的交换周期分别为3和6 d.最后,以COd为例,给出了在排放稳定后保守污染物的分布特征.A modified 2-D estuarine coastal ocean model(ECOM) with moving boundaries is used to reproduce the tidal regime in the Fuqing Bay.Simulations agree with observations reasonably.By means of estimation,it is found that the current duration of flooding and ebbing are 6 h 19 min 2 s and 6 h 3 min 48 s,respectively.The tidal prism during the spring and neap are 10.94×107 and 4.47×107 m3,respectively.Additionally,the conservative COD is added to the model.Based on the transport character of conservative tracers,the half and 80% of water exchange period are 3 and 6 days,respectively.中国科学院海洋环流与波动重点实验室开放研究基金(KLOCAW0804)资

Improvements on the new relaxation & bubble point method in the continuous distillation calculation

[中文文摘]结合新松弛法和泡点法,对多元精馏塔进行稳态模拟计算。为了克服松弛法迭代缓慢的缺点,本文对新松弛法算法进行了分析,提出了两处改进:引入θ法进行圆整归一以加速迭代,以及应用塔板水力学方程来求算收敛因子。通过两个实例仿真表明,改进后的新松弛一泡点法不仅继承了松弛法算法简易性和通用性等优点,所费计算机时较少,可适用于多股进料、多股侧线采出和多个中间换热器的多组分复杂精馏过程。[英文文摘]New Relaxation Method and Bubble Point Method were usually combined in the rigorous continuous distillation calculations. To ameliorate the slow convergence rate of Relaxation Method, two improvements were put forward in this paper:θ Method to accelerate the calculation and Plate Hydraulics Correlation to fix on the value of Convergence Factor in New Relaxation Method. The results of two examples showed that the improved New Relaxation & Bubble Point Method inherited all the merits of New Relaxation Method, and furthermore, made a greal dent in facilitating the convergence rate and shortening the computational time

Dynamic Modeling and Simulation for Bed Temperature of Circulating Fluidized Bed Boiler

[中文文摘]在分析了循环流化床锅炉床内温度动态特性的基础上,通过对循环流化床锅炉动态特性的主导过程-动态物料平衡,动态残碳量平衡以及动态能量平衡以及辅助过程-氧气浓度平衡,焦炭颗粒能量平衡的描述,建立了以给煤、一次风、二次风和排渣为输入变量的动态模型.结合某220 t/h循环流化床锅炉的现场数据,采用MATLAB 6.5软件对所建模型进行了连续脉冲动态仿真和实时仿真,连续脉冲动态仿真结果可以很好地反映输入脉冲变量发生变化时床温的动态响应情况,实时仿真结果与现场采集到的数据能够很好吻合.[英文文摘]Based on the analysis of dynamic traits of CFBB,this paper gave good descriptions of dynamic processes of CFBB,such as dynamic mass balance of total bed inventory,dynamic carbon mass balance and dynamic energy balance.Then a simplified model was then proposed for the dynamic simulation of the bed temperature of CFBB,which considered the rate of coal feed,primary air,secondary air and bottom ash removal as inputs.Combining with the data obtained from the actual process of a 220t/h CFBB,the step changes simulation and the real2time simulation were implemented by the powerful technical2computing language - Matlab 6. 5. The results of the step change simulation reflected well the transient dynamic response of bed temperature when inputs were changed ,and the real-time simulation was in good agreement with the actual data