钨硅酸催化合成乙酸辛酯

以钨硅酸为催化剂，通过乙酸和辛醇反应合成了乙酸辛酯。探讨了酸醇物质的量比、催化剂用量以及反应时间对酯化率的影响。实验结果表明：钨硅酸催化合成乙酸辛酯的最佳条件为：酸醇物质的量比1．3：1，催化剂用量0．2g／0．1mol(辛醇)，带水剂(环己烷)10mL，反应时间1h．温度100～118℃．在此条件下其酯化率可达99．30％。     

新型固体酸催化合成乙酸乙酯

以铁钾矾为催化剂,通过乙醇和乙酸反应合成乙酸乙酯,并对影响酯化率的因素进行了研究．结果表明最佳条件为：催化剂用量为0．6g／0．05mol冰乙酸,醇酸物质的量比为1．2：1,带水剂（苯）15mL,反应温度为73～78℃,反应时间为120min,酯化率可达96．78％．     

硫酸氢钠作为合成己酸异戊酯催化剂的研究

利用硫酸氢钠作为酯化反应催化剂合成了己酸异戊酯，确定了其最佳反应条件为：催化剂用量为0．2g／0．1mol己酸，醇酸物质的量比为1．5：1，带水剂环己烷10mL，回流反应时间1．5h，己酸的酯化率可达99．39％。实验表明该催化剂催化效果好，使用量少，酯化率高，环境污染小，廉价易得，很有应用价值。     

硫酸铁催化合成乙酸异戊酯

以乙酸和异戊醇为原料,采用硫酸铁作催化剂来合成乙酸异戊酯.考察了乙酸与异戊醇的物质的量比、催化剂用量及反应时间对乙酸酯化率的影响.结果表明:硫酸铁对合成乙酸异戊酯具有良好的催化活性,酯化反应的最佳条件为:酸醇物质的量比为1:1.3(乙酸用量为0.1mol),催化剂用量为0.9 g,回流反应1 h,酯化率可达96.69%.     

乙酸和异戊醇酯化反应催化剂的研究

乙酸异戊酯是由乙酸和异戊醇在催化剂条件下制得的．通过改变酯化反应中的催化剂并优选出最佳反应工艺条件,提高了酯化反应的收率,产物的后处理容易,避免了设备腐蚀,具有一定的工业应用价值     

硫酸铜催化合成癸二酸二丁酯的研究

利用硫酸铜作为酯化反应催化剂合成了癸二酸二丁酯，其最佳反应条件为：催化剂用量3．0g/0．05mol癸二酸，醇酸摩尔比为4，反应时间3．0h，带水剂12ml，癸二酸的酯化率可达97．23％，该催化剂催化效果好，使用量少，酯化率高，可重复使用，无环境污染，价廉易得，是一种极有应用价值的催化剂。     

固体催化剂SnCl4/C的制备及其催化酯化反应研究

制备了固体催化剂SnCl4／C，并通过乙酸苄酯的合成考察了该催化剂对酯化反应的催化情况，结果表明，固体催化剂SnCl4／C对酯化反应有很好的催化活性。适宜的反应条件为：当酸的用量为0．20mol，醇酸物质的量比为1．4，催化剂用量为1．0g，带水剂甲苯为15mL，反应时间为2．5h，反应温度为100～110℃时，酯化率达92％以上。     

磷钨杂多酸催化合成乙酸正己酯

以磷钨杂多酸为催化剂,通过乙酸和正己醇的酯化反应合成了乙酸正己酯,并对影响酯化率的因素进行了研究.结果表明:反应的最佳条件为:乙酸为0.1 mol时,醇酸物质的量比为1.4,催化剂用量为0.3 g,带水剂为15 mL,在温度为110~130℃下,反应30 min,酯化率可达99.6%以上.     

活性炭固载对甲苯磺酸催化合成乙酸正己脂

制备了活性炭固载对甲苯磺酸催化剂,以乙酸和正己醇为原料合成了乙酸正己酯,考察了影响酯化率的各种因素,确定了最佳反应条件为:乙酸用量为0.1 mol时,醇酸物质的量比为1.4,催化剂用量为3 g,15 mL甲苯作带水剂,反应时间30 min,酯化率达94%以上.     

SO_4~(2-)/ZrO_2-SiO_2催化剂的制备及应用

本文采用沉淀法制备了SO_4~2-/ZrO_2-SiO_2固体酸催化剂,而且将其应用于乙酸正丁酯的酯化反应中。考察了锆硅摩尔比、催化剂用量、焙烧温度等反应条件对催化活性的影响,并得出了最佳的酯化反应制备条件:冰乙酸与正丁醇摩尔比为1∶1.2;n(Zr)∶n(Si)为1∶5,浸渍液H_2SO_4浓度为1.5mol/L,焙烧温度为700℃,催化剂用量为3.0wt%,得到最大酯化率为85.22%,同时催化剂连续使用5次后酯化率仍能达到84.10%。     

Analysis of aroma-active compounds in three sweet osmanthus (Osmanthus fragrans) cultivars by GC-olfactometry and GC-MS

Objective: Aroma is the core factor in aromatherapy. Sensory evaluation of aromas differed among three sweet osmanthus (Osmanthus fragrans) cultivar groups. The purpose of this study was to investigate the aroma-active compounds responsible for these differences. Methods: Gas chromatography-olfactometry (GC-O) and GC-mass spectrometry (GC-MS) were used to analyze the aroma-active compounds and volatiles of creamy-white (’Houban Yingui’, HBYG), yellow (’Liuye Jingui’, LYJG), and orange (’Gecheng Dangui’, GCDG) cultivars. Results: Seventeen aroma-active compounds were detected among 54 volatiles. trans-β-Ocimene, trans-β-ionone, and linalool, which were major volatiles, were identified as aroma-active, while cis-3-hexenyl butanoate, γ-terpinene, and hexyl butanoate were also aroma-active compounds, although their contents were low. Analysis of the odors was based on the sum of the modified frequency (MF) values of aroma-active compounds in different odor groups. HBYG contained more herb odors, contributed by cis-β-ocimene and trans-β-ocimene, while LYJG had more woody/violet/fruity odors released by trans-β-ionone, α-ionone, and hexyl butanoate. In GCDG, the more floral odors were the result of cis-linalool oxide, trans-linalool oxide, and linalool. Conclusions: Aroma-active compounds were not necessarily only the major volatiles: some volatiles with low content also contributed to aroma. The aroma differences among the three cultivars resulted from variation in the content of different odor groups and in the intensities of aroma-active compounds.     

Surface pattern based on an azobenzene-containing copolymer thin film and its light-driven morphology modulation

A type of azobenzene-containing block copolymer polymethyl methacrylate-b-poly (n-butylmethacrylate-co-6-(4-(phenylazo) benzoate) hexyl methacrylate) (PMMA-b-(PnBMA-co-PAzoMA)) was synthesized by the atom transfer radical polymerization (ATRP). Macroinitiator polymethyl methacrylate (PMMA) was prepared by ATRP and used to initiate the copolymerization of monomer n-butyl methacrylate (nBMA) and azobenzene-based methacrylate monomer (AzoMA). Herein, three block copolymers with different molecular weights and block volume fractions were obtained and spin-coated on a silicon substrate or quartz plate before annealing at 180 °C for 14 h. The surface morphologies in these annealed copolymer films were observed by atomic force microscopy (AFM). Bicontinuous stripe or island patterns with different sizes were formed dependent on the film thickness. These ordered patterns are considered to be formed arising from the dewetting process of the surface layer in the copolymer film. Photoisomerization of azobenzene units in the copolymer films changed the dewetting behaviors of the surface layer of the thin film. Therefore, some copolymer annealed films showed a reversible morphology conversion between bicontinuous stripe and island structure when exposed to UV light and upon being stored in the dark. It was found that the composition of the block copolymer had obvious influences on the photoinduced morphology conversion behaviors in these copolymer thin films. When the volumes of PnBMA and PAzoMA phases in the block copolymer were large enough, the surface morphology could be modulated by UV light irradiation and storage in the dark. This work proposes a new possibility for photoinduced control and design of the dewetting processes of thin films using a linear block copolymer.     

对as一些特殊用法的研究

as是英语中使用率很高的一个词,而且其用法很复杂.本文主要对as的一些疑难用法进行了研究,重点论述了as作关系代词表示主句所表达的整个概念;as作连词引导让步状语从句;as表达类比;及as构成as much as,not as much as四方面的疑难用法.     

大学生心理健康教育的三个维度

基本心理素质的体现是心理健康,心理健康的一个典型特征就是心理平衡,就是在短暂的心理冲突之后便迅速复归心理平衡。心理平衡,就是在剧烈竞争中建立健康、协调、和谐的人际教育关系,这既是个人的需要,也是集体的需要;既是教师的需要,也是学生的需要;既是学校的需要,也是社会的需要;既是学习的需要,也是情感的需要。     

以人为本:科学发展观的基本价值取向

以人为本是科学发展观的实质和核心,是科学发展观的起点和归宿。坚持以人为本既要重视人民,又要重视人人;既要重视“群体”的量的价值,又要重视“个体”的量的价值;既要关注国民生产总值,又要关注国民幸福指数。     

‘When I am being rushed it slows down my brain’: constructing self-understandings as a mathematics learner

Understanding learning disabilities (LDs) as constructed through multiple cultural practices including discourse, this paper focuses on a Latino middle school student with a LD named Elijah. This study documents both the discourses and practices used to position Elijah as a mathematics learner, as well as his use of similar discourses as he constructs a complex set of self-understandings as a mathematics learner. Elijah is positioned by discourses that prioritise speed as an indicator of mathematical ability, as well as discourses that construct students with LD as having both intelligence and differences such as processing speed. An analysis of interview and observational data suggests that Elijah constructed a unique set of self-understandings as a mathematics learner. Like his sixth-grade special education teacher, Elijah seems to differentiate between knowledge and the performance of knowledge in school. He created a unique identity as both ‘fast’ and ‘slow’ in mathematics, rejecting the binary found in many mathematics classrooms. These findings suggest that multiple discourses circulate in schools about ability and disability in mathematics.     

Developing a Professional Identity as an Elementary Teacher of Nature of Science: A self-study of becoming an elementary teacher

This study explores the development of professional identity as a teacher of nature of science (NOS). Our research question was ‘How can a teacher develop a professional identity as an elementary teacher of NOS?' Through a researcher log, videotaped lessons, and collection of student work, we were able to track efforts in teaching NOS as part of regular classroom practice. A team of four researchers interpreted the data through the Beijaard et al. professional identity framework and found that it was not as simple and straightforward to teach NOS as we predicted. Development of professional identity as a teacher of NOS was influenced by contextual factors such as students, administration, and time, as well as personal struggles that were fraught with emotion. Development took place through an interpretation and reinterpretation of self through external factors and others' perceptions, as well as the influence of sub-identities.     

新时期高校图书馆对学生读者的导向作用

本文以新时期高校图书馆作为研究平台,以学生读者作为研究对象,以工作实践和较普遍的现象作为研究内容,以导向措施作为切入点,论述了现代图书馆“以人为本”“服务至上”的图书馆工作理念,探索了图书馆和学生读者互动发展的思路。     

船山之诗歌节奏观简议

船山诗学将诗歌视为以乐章美为核心的审美整体。这一乐章美效果是通过多层次的节奏运动来实现的,主要表现为诗歌的意义节奏、语体节奏和情感节奏三层。具体来说,在船山诗论中,诗歌的整体音乐性被视为一种基本的诗歌特质,可看作一种本体,三种节奏作为诗歌音乐性的重要表征,可视为具体的"用"。在这个"一体三用"的关系中,作为诗歌之"体"的音乐性对各种节奏有统摄作用,作为具体之"用"的不同节奏则对诗歌的音乐性有凸显作用。