用∑WESH图评价某涂料化工厂的可持续性

介绍了在清洁生产过程中用∑WESH图评价涂料化工厂的可持续发展的原理及方法,并进行了一个实例的评价.从该厂的∑WESH图得出该厂的水及能源的利用率高,所用的原材料的稀缺性都不大,唯一较严重的问题是二甲苯的通过量大,危害性较严重.因此建议该厂在配方上尽量减少二甲苯的使用,开发新产品.     

喷涂前处理污染源的分析及其处理措施

随着我国国民经济的快速发展和国家"节能减排"重点项目的深入开展,各种污染源的分析及其处理措施的研究备受关注.本文在充分研究若干家电企业的钢铁喷涂制件的前处理工艺(如:预脱脂、脱脂、清洗、表调、磷化等)的基础上,分析喷涂前处理过程中的污染源,研究污染源的处理措施.     

酿酒酵母细胞表达异源萜类化合物的研究进展

萜类化合物具有可观的经济价值,但是目前的生产过程复杂、产量低。酿酒酵母甲羟戊酸途径为萜类化合物的合成提供直接前体,因此酿酒酵母细胞具有合成异源萜类化合物的天然优势。对酿酒酵母甲羟戊酸途径的清晰认识是对其进行有效利用的基础,本文从代谢途径、关键酶的特点和全局调控机制3个方面对该途径进行了介绍。从代谢途径的构建和优化、模块与底盘细胞的适配、模块构建及组装方式的角度概述了酿酒酵母细胞异源合成单萜、倍半烯萜、二萜、三萜类化合物的研究进展。指出实现酿酒酵母高效合成萜类化合物所需要解决的基础问题是对酿酒酵母甲羟戊酸途径进行更为全面了解和对萜类化合物的天然代谢途径进行明确解析;另外,合成生物学的进一步发展也将为此提供应用基础。     

香叶油的研究进展

为了全面了解香叶油的研究现状,为我国香叶油的开发利用提供思路, 综述了香叶的栽培、组培技术研究、香叶油的应用、香叶油的提取及化学成分研究、香叶油调配研究等方面的现状,并对香叶品种的遗传改良提出一些有益的建议.     

胶原纤维的性能特点和作用

1胶原纤维巴西Novaprom胶原纤维是以精选的牛皮内剖层(真皮)组织提取的,它不同于明胶或明胶的衍生物。它的生产是在严格控制的时间和温度范围内进行的,从而确保其主要成分──胶原蛋白的活性不变,并以天然纤维的形式存在。它在肉制品中的结构呈纤维状而不是一般的胶冻,因而这种结构是非常稳定的,是不可逆的。它是很好的功能性动物纤维蛋白,在肉制品及鱼糜制品等相关的食品中得到广泛的应用。2胶原纤维的性能及相关指标(1)蛋白质含量:胶原纤维中的动物蛋白质(M×6.25)高达98%,含有人体必需的氨基酸。(2)吸水、持水性:胶原纤维结构良好,呈矩…     

鲜为人知的科学珍闻

有言在先,珍闻的挑选奉行以下原则:科学应该是有趣的,科学之所以好玩,部分原因在于你了解、知道这些奇谈怪论的存在。科学的伟大之处在于,它不必是教条的、有价值的实验,也不要求对所有理论进行最准确的过滤以得     

玻璃纤维拉丝池窑配合料设备研制的进展

玻璃纤维池窑拉丝生产线配合料的制备中,原料是形成优质玻璃液的基础,因此可以说配合料的稳定性、均匀性和准确性对玻璃纤维的质量起着决定的作用.生产实践证明:组分和粒度均匀的配合料,不但能强化玻璃液的熔化和澄清过程,而且还能减少或消除影响玻璃质量的各种弊病.所以认真拟定玻璃纤维原料的成分和选择玻璃纤维的种类和化学性质:严格控制进厂原料化学成分、粒度和水份;做好原料的分堆、存放、加工、称量、混合、输送是优质配合料制备不可缺少的手段,这也是做好玻璃纤维池窑配合料的基本任务.     

氢氧化镁阻燃剂的研究进展

主要论述了国内外阻燃剂的种类和发展,指出由于环境和健康的原因,无机阻燃剂是最有发展前途的,其中的氢氧化镁因其特有的性质,在无机阻燃剂中尤为突出.考虑到氢氧化镁的广泛应用的前景和其本身的缺点,对其改性成为业界的研究重点,其中主要介绍了钛酸酯、硬脂酸(盐)、镁盐晶须和胶囊化等技术,指出以后的发展方向是在改性基础上的协同作用.     

高浸透性大分子聚酯乳液的研制

1前言 随着池窑生产的发展,原有的浸润剂在快速浸润性和快速浸透性方面无法得到满足.意大利DSM公司聚酯乳液是公认的喷射纱浸润剂最好的成膜剂.本项目的目的是研制出能工业化生产的与DSM公司产品质量相当的聚酯乳液,替代进口,节约外汇,满足我国池窑发展需要,争创良好的经济社会效益.     

宁静——使艺术深华

宁静的山是心灵的绘画,宁静的水是灵魂的诗篇,宁静的夜是精神的书籍。在这越来越充斥着物欲纵横的社会,浮躁成了现代人的代名词,而保持一颗宁静的心,尤其在艺术创作中显得尤为重要。     

GO物理形态对复合光催化剂性能的影响

以钛酸四丁酯以及固态和液态的氧化石墨烯(GO)为前驱物,分别制备了标记为TiO_2-RGO(s)和TiO_2-RGO(l)的复合光催化剂。对制备的2种复合光催化剂进行了表征,并以亚甲基蓝(MB)为目标物,对比研究了2种催化剂的光催化效能。结果表明,TiO_2-RGO(l)和TiO_2-RGO(s)的能级带宽分别降低至2.8、2.9 e V;二者光降解MB的效能均优于TiO_2自身,且降解效率随着GO含量的增加而增加;当TiO_2与GO的质量比为1∶0.06时,TiO_2-RGO(l)和TiO_2-RGO(s)对MB的降解率分别为96%和84%。动力学研究表明:TiO_2-RGO(l)和TiO_2-RGO(s)的准一级反应速率常数分别是TiO_2的3.2倍和2.2倍。     

The effect of the length of the oxyethylene chain on the conductivity of the polyurethaneurea electrolyte

Polyurethaneureas (PUU), which were synthesized from 4,4′-diphenylmethane diisocyanate (MDI), poly(ethylene glycol) (PEG), and 3,5-diaminobanzoic acid (DABA), were used as polyelectrolytes in this study. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FT-IR) were used to monitor the effect of the various kinds of PEG on the changes in morphology of PUU electrolytes corresponding to the concentration of lithium perchlorate (LiClO₄) dopants. The results of DSC and FT-IR indicate the Li⁺ ions coordinate with the soft and hard segments. Additionally, the crystallinity of the PEG soft segment and the ordered hydrogen-bonded urea carbonyl groups decreased with increasing salt concentration. Impedance spectroscopy (IS) measurements show that the PUU electrolyte with the high phase separation degree has the high ionic conductivity. The hard-segment T_g and the soft-segment T_m influence the conductivity behavior of polyelectrolytes with increasing measurement temperature.     

Impact of the soak and the malt on the physicochemical properties of the sorghum starches

Starches were isolated from soaked and malted sorghum and studied to understand their physicochemical and functional properties. The swelling power (SP) and the water solubility index (WSI) of both starches were nearly similar at temperatures below 50 °C, but at more than 50 °C, the starch isolated from malted sorghum showed lower SP and high WSI than those isolated from raw and soaked sorghum. The pasting properties of starches determined by rapid visco-analyzer (RVA) showed that malted sorghum starch had a lower viscosity peak value (86 BU/RVU) than raw sorghum starch (454 BU/RVU). For both sorghum, X-ray diffractograms exhibited an A-type diffraction pattern, typical of cereal starches and the relative degrees of crystallinity ranged from 9.62 to 15.50%. Differential scanning calorimetry (DSC) revealed that raw sorghum starch showed an endotherm with a peak temperature (Tp) at 78.06 °C and gelatinization enthalpies of 2.83 J/g whereas five-day malted sorghum starch had a Tp at 47.22 °C and gelatinization enthalpies of 2.06 J/g. Storage modulus (G') and loss modulus (G″) of all starch suspensions increased steeply to a maximum at 70 °C and then decreased with continuous heating. The structural analysis of malted sorghum starch showed porosity on the granule's surface susceptible to the amylolysis. The results showed that physicochemical and functional properties of sorghum starches are influenced by soaking and malting methods.     

Study of the mechanism of the antioxidant action of ethoxyquin

A study has been carried out of the reaction of 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline (ethoxyquin, I ) with alkylperoxyls. In the presence of a relatively low concentration of 1-cyano-1-methylethylperoxyl, I reacts to form dimer IV (8-(6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinolin-1-yl)-6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline) as the main product and quinoline derivative III (2,4-dimethyl-6-ethoxyquinoline), as a side product, i.e., substances formed by the conversion of the aminyl II (6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinolin-1-yl) alone. Smaller amounts of p-quinoneimine VI and o-quinoneimine VIII (2,2,4-trimethyl-2,6-dihydro-6-quinolone and 6-ethoxy-2,2,4-trimethyl-2,8-dihydro-8-quinolone) have been found; these substances are formed by further oxidation of II . In the presence of relatively high concentrations of tert-butylperoxyls, peroxide IX (6-tert-butylperoxy-6-ethoxy-2,2,4-trimethyl-2,6-dihydroquinoline) is formed as the main product. Substance IX thermally decomposes to form VIII , while in the presence of weak acids IX is converted into VI as the main product. Dimer IV is a medium-strength antioxidant which is gradually converted into 8-(6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinolin-1-yl)-2,2,4-trimethyl-6-quinolone (XI) and 8-(6-ethoxy-3-hydroxy-2,2-dimethyl-4-methylene-1,2,3,4-tetrahydroquinolin-1-yl-)-2,2,4-trimethyl-2,6-dihydro-6-quinolone) (XII) . The methyl group in XI actively participates in the antioxidation process. When formed, nitroxide V (6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinolin-N-oxyl) acts as an efficient antioxidant which, however, does not participate in the cyclic mechanism that is employed to explain the action of antioxidants of the HALS type. The antioxidant properties were evaluated on the basis of their effect on the course of the autoxidation of squalene.     

关于化肥对作物产量贡献的评估问题

化肥对作物产量的贡献率包括化肥对当季作物产量的贡献、化肥后效的贡献和由化肥增殖的有机肥的贡献,即Ct%=CNPK当%+CNPK后%+CNPK有%。以玉米为例,按某一肥料配比计算化肥对玉米产量的总贡献率为58.6%,与国内外从中长期试验中获得的化肥实际贡献率在50%左右相似,明显高于化肥对当季作物的增产率(34.6%),远高于单一养分(氮)对作物产量的贡献率(18.2%)。     

Identification of the Catalytic Residues in the Cyclase Domain of the Class IV Lanthipeptide Synthetase SgbL

Lanthipeptides belong to the family of ribosomally synthesized and post-translationally modified peptides (RiPPs) and are subdivided into different classes based on their processing enzymes. The three-domain class IV lanthipeptide synthetases (LanL enzymes) consist of N-terminal lyase, central kinase, and C-terminal cyclase domains. While the catalytic residues of the kinase domains (mediating ATP-dependent Ser/Thr phosphorylations) and the lyase domains (carrying out subsequent phosphoserine/phosphothreonine (pSer/pThr) eliminations to yield dehydroalanine/dehydrobutyrine (Dha/Dhb) residues) have been characterized previously, such studies are missing for LanL cyclase domains. To close this gap of knowledge, this study reports on the identification and validation of the catalytic residues in the cyclase domain of the class IV lanthipeptide synthetase SgbL, which facilitate the nucleophilic attacks by Cys thiols on Dha/Dhb residues for the formation of β-thioether crosslinks.     

制备双羟基四配位硅反应速率常数的测定

探讨了用电导法跟踪高反应活性的五配位硅钾化合物与2-氯乙醇反应制备双羟基四配位硅化合物的动力学行为,从而确定该反应的反应级数为二级反应,得出在甲醇体系中反应的速率常=1.233h、t53℃=数k64℃=1.818(mol/dm3)-1·h-1、k53℃=0.4437(mol/dm3)-1·h-1,半衰期t64℃11225.051h,和该反应的活化能Ea=86.987kJ/mol。     

Contribution to the study of the kinetic mechanism of aluminous cement setting II - Release of the factor resposible for breaking the latent period by the dissolution of a fraction of the initial cement

The comparison of Wells (W) and filtrate development (B) curves, published in the first article (1) led us to conclude that there is no heterogeneous nucleation during the latent period either for the aluminous cement (Fondu) or for pure monocalcium aluminate (CA). This new study aims to supply new experimental data showing clearly that the factor responsible for instant hydrate precipitation, i.e. for breaking the latent period, is related too the dissolution of a fraction of initial cement, this factor being liberated by such dissolution.     

树形分子的制备及对量子点荧光性能的影响

采用发散法合成了以乙醇胺为初始核的扇形树枝状化合物PAMAM,用核磁共振法（^1H NMR和^13C NMR）对G1．0—NH2,G1．0-SH进行了表征,证实了其结构;并用荧光分光光度计检测了PAMAM对CdTe量子点水溶液的荧光性质的影响。发现PAMAM树形分子可增强CdTe—TGA量子点的荧光,不同浓度的PAMAM对量子点荧光性能的影响不同。     

两亲性无规共聚物MAA-SMA-PEGMA的表面活性研究

利用功能性单体甲基丙烯酸(MAA)、甲基丙烯酸十八烷基酯(SMA)和聚乙二醇甲基丙烯酸酯(PEG-MA)通过自由基共聚,合成了两亲性共聚物Poly(MAA-SMA-PEGMA)。研究了其结构、临界胶束浓度(CMC)和表面张力,探讨了由共聚物与低分子表面活性剂组成的复配体系。结果表明高低分子表面活性剂复配体系在质量比为5∶5后,体系的表面张力和临界胶束浓度都有所降低,接近于低分子表面活性剂。