检索结果-南通市图书馆

三元低共熔溶剂预处理对龙竹酶解糖化和乙醇发酵的影响

在线全文

学校读者我要写书评

暂无评论

林业工程学报 2025年第1期10卷 86-96页

作者：曹静刘昭明杨海艳史正军王大伟石纯杨静西南林业大学材料与化学工程学院昆明650224 云南省高校特色林木生物质资源化学利用重点实验室西南林业大学昆明650224

笔者以滇产龙竹为原料,通过对其进行三乙基苄基氯化铵/草酸(TEBAC/OA)二元低共熔溶剂(DES)和TEBAC/OA/H_(2)O三元DES预处理,以预处理底物的酶解糖化效率和乙醇发酵浓度作为预处理性能的评价指标,并对比分析预处理前后龙竹和再生木质素... 详细信息

笔者以滇产龙竹为原料,通过对其进行三乙基苄基氯化铵/草酸(TEBAC/OA)二元低共熔溶剂(DES)和TEBAC/OA/H_(2)O三元DES预处理,以预处理底物的酶解糖化效率和乙醇发酵浓度作为预处理性能的评价指标,并对比分析预处理前后龙竹和再生木质素的结构特征,探索TEBAC/OA/H_(2)O三元DES预处理的机制。试验结果表明:在TEBAC/OA和H_(2)O物质的量比为1∶5,反应温度为140℃,反应时间为6 h时,三元TEBAC/OA/H_(2)O预处理对龙竹的木质素脱除率为90.53%;底物预处理在酶用量为13 FPU/g底物的情况下,酶解得率由二元DES的54.70%增加至70.77%,相应地,发酵乙醇含量由13.25 g/L提高至18.33 g/L。X射线光电子能谱、X射线衍射和比表面积与孔径分析结果显示,三元DES与二元DES预处理相比,底物的表面木质素覆盖率和结晶度/纤维素含量比值分别降低了16.62%和28.57%,比表面积增加了16.23%;同时,底物的疏水度、聚合度分别降低了47.93%和6.72%,纤维素酶可及度增加了28.80%,表明三元DES预处理可使纤维素发生一定程度的润胀,无定型区域的部分木质素和半纤维素被去除,这能够为纤维素酶提供更多的活性位点。此外,木质素的核磁共振结果表明,与二元DES预处理相比,三元DES预处理可更好地保留再生木质素的完整性,且对木质素的缩合反应有一定的抑制作用。本研究结果为开发生物质能源、材料和化学品等提供了一定的参考价值。

关键词：龙竹低共熔溶剂预处理酶水解乙醇发酵

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

五种乔灌木鲜花挥发物成分与香气特征分析

天然产物研究与开发 2025年第1期37卷 74-84页

作者：裴诗纯童莹袁黎娜姚雷张楠上海交通大学设计学院上海200240 上海交通大学芳香植物研发中心上海200240

为探究香樟、日本女贞、大花六道木、阔叶十大功劳和穗花牡荆的鲜花应用价值,采用顶空动态采样及热脱附-气相色谱质谱联用法对其挥发物进行定性定量分析,并结合香气活力值评估其释香强度和香气特征。香樟与阔叶十大功劳鲜花均呈明显花香... 详细信息

为探究香樟、日本女贞、大花六道木、阔叶十大功劳和穗花牡荆的鲜花应用价值,采用顶空动态采样及热脱附-气相色谱质谱联用法对其挥发物进行定性定量分析,并结合香气活力值评估其释香强度和香气特征。香樟与阔叶十大功劳鲜花均呈明显花香,前者主成分为樟脑和芳樟醇,后者主成分为顺式-β-罗勒烯,且香樟花释香强度与香气活力值远高于其他四种植物。大花六道木和日本女贞花香主成分均含苯甲醛和苯乙醛,主要呈甜香特征。穗花牡荆花香主成分为乙酸叶醇酯和桧烯,香气特征较为复杂。五种乔灌木花香中均有较高含量的保健成分,特别是香樟花在保健园林和芳香疗法中有较好的潜在应用前景。

关键词：乔灌木鲜花挥发物香气强度香气活力值

在线全文

学校读者我要写书评

暂无评论

本溪市区城集镇山洪灾害分析评价

东北水利水电 2025年第1期43卷 50-52页

作者：史春阳辽宁省河库管理服务中心(辽宁省水文局) 辽宁沈阳110003

山洪灾害属于较为严重的自然灾害,其防治需要借助科学的理论技术作为支持。本文对本溪市区城集镇山洪灾害进行了系统的分析评价,确定了危险区等级危险区人口及预警指标,以期为本溪市区山洪灾害防御提供理论依据。

关键词：本溪市区山洪灾害预警指标危险区人口

Valence electron structure and hydrogen storage property of LaNi_-4Co

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2015年第4期34卷 259-266页

作者： Lei Zhang shi-chun Li School of Electromechanical Automobile Engineering Yantai University Key Laboratory of Advanced Manufacturing and Control Technology in Universities of Shandong Materials Department College of Electromechanical Engineering China University of Petroleum

In the present study, two models of atom occupation in LaNi4Co were put forward and corresponding valence electron structures （VESs） of these two models were investigated according to empirical electron theory （EET） of solids and molecules. Results demonstrate that the VES-concerned hardness factor （FH） of LaNi4Co is lower than that of LaNi5, so LaNi4Co has lower hardness, higher plasticity and improved anti-pulverization ability. In the mean time, the difference of the equilibrium hydrogen pressure between LaNiaCo and LaNi5 was analyzed in the electronic level. The analysis shows that the strength of the weakest bond net in octahedron lattice interstices of LaNi4Co is much lower than that in LaNis; consequently, LaNi4Co＇s bond net easily deforms to accommodate hydrogen so that LaNi4Co has lower equilibrium hydrogen pressure in comparison with LaNis. The results can provide some theory guide on the design of hydrogen storage alloys.

关键词： Alloys Computer modeling and simulation Electronic structure Mechanical properties

ITPK1 functions as both a kinase and an ADP phosphotransferase in Pi signaling

在线全文

学校读者我要写书评

暂无评论

Molecular Plant 2021年第11期14卷 1784-1785页

作者： chun-Lin shi ANGENOVO 1414 VikenNorway College of Horticulture South China Agricultural UniversityGuangzhou 510642China

Phosphorus is one of mineral elements essential for plant growth and *** cope with low phosphate(Pi)conditions,plants have evolved complex signaling mechanisms including the inositol phosphate(InsP)signaling pathway in which the phosphate starvation response(PHR)transcription factors control the expression of Pi starvation-induced genes in a Pi-dependent *** activities of PHRs are regulated by their interactions with SPX proteins that act as receptors for inositol pyrophosphates(PP-lnsPs),such as lnsP7 and *** plants,the syn thesis of lnsP8 is mediated by the bifunctional kinase/phosphatase enzymes,VIH1 and ***,lnsP6 kinases responsible for the synthesis of lnsP7 in plants have long remained elusive.

关键词： development. ITP synthesis

曙厉蝽和益蝽线粒体基因组全序列特征及系统发育分析

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

生物技术通报 2025年第1期41卷 312-323页

作者：江宏燕陈世春廖姝然陈亭旭王晓庆重庆市农业科学院茶叶研究所重庆402160

【目的】曙厉蝽(Eocanthecona concinna)和益蝽(Picromerus lewisi)是农林业害虫重要的捕食性天敌昆虫资源,为了解其线粒体基因组的特点与差异,探究益蝽亚科昆虫的系统发育关系,对两种蝽类天敌昆虫的线粒体基因组序列进行测定及分析。... 详细信息

【目的】曙厉蝽(Eocanthecona concinna)和益蝽(Picromerus lewisi)是农林业害虫重要的捕食性天敌昆虫资源,为了解其线粒体基因组的特点与差异,探究益蝽亚科昆虫的系统发育关系,对两种蝽类天敌昆虫的线粒体基因组序列进行测定及分析。【方法】通过测序后拼接、校正、注释获得两种蝽的线粒体全基因组序列,并利用最大似然法构建了基于益蝽亚科昆虫13个蛋白质编码基因(protein-coding gene, PCG)序列的系统发育树。【结果】曙厉蝽和益蝽线粒体基因组大小分别为18 740 bp(GenBank登录号:OR979468)和17 181 bp(GenBank登录号:OR972558),均包括13个PCG、2个核糖体RNA基因(rRNA)、22个转运RNA基因(tRNA)和1个控制区,基因排列与典型的蝽科昆虫相同。曙厉蝽和益蝽线粒体基因组控制区均位于rrnS和trnI之间,长度分别为3 862和2 438 bp,结构差异较大,均包含了不同长度的随机复制区域。对比益蝽亚科昆虫的线粒体基因组全序列和PCG序列的相似度,结果显示同属之间相似度较高,益蝽不同样本PCG序列的相似度超过98%。系统发育分析结果表明益蝽属(Picromerus)的昆虫聚为一支,曙厉蝽、叉角曙厉蝽(E. furcellata)、黑曙厉蝽(E. thomsoni)(GenBank登录号:OP920755)聚为一支,曙厉蝽属与益蝽属的亲缘关系最近,两个属与疣蝽属(Cazira)亲缘关系较远。【结论】明确了两种蝽类天敌昆虫线粒体基因组的特征,构建了益蝽亚科昆虫的系统发育关系,结果与传统分类学鉴定结果一致。

关键词：曙厉蝽益蝽线粒体基因组益蝽亚科系统发育

同方期刊数据库

Synthesis and Crystal Structure of 3,5-Diphenyl-1,2-di(4-chlorophenyl)pyrrole

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2005年第11期24卷 1314-1317页

作者： shi Da-Qing shi chun-Ling ZHUANG Qi-Ya Department of Chemistry Xuzhou Normal University Xuzhou Jiangsu 221116 China Key Laboratory of Biotechnology on MedicalPlants of Jiangsu Province Xuzhou 221116 China

The title compound （C28H19Cl2N） has been synthesized by the reaction of dibenzoylmethane and N-（4-chlorobenzylidene）-4-chlorobenzenamine promoted by low-valent titanium reagent, and characterized by elemental analysis, IR, ^1H NMR and X-ray single-crystal diffraction. The crystal belongs to monoclinic, space group P2 1/C with a = 9.952（2）, b = 9.863（2）, c = 23.460（6） A, β = 99.62（2）°, V = 2270.4（9） A^3, Mr = 440.34, Z = 4, Dc = 1.288 g/cm^3, μ（MoKa） = 0.301 mm^-1, F（000） = 912, the final R = 0.0387 and wR = 0.0793. X-ray analysis reveals that the four phenyl rings in the pyrrole ring are not coplanar.

关键词： pyrrole low-valent titanium reagent crystal structure

Synthesis and Crystal Structure of 1-(4-Chlorophenyl)-2-cyano-3-amino-3a-hydroxy- 3a,3b,6,7-tetrahydrobenzo[4,5]indene

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2005年第12期24卷 1393-1396页

作者： shi Da-Qing shi chun-Ling RONG Liang-Ce Department of Chemistr） Xuzhou Normal University Xuzhou 221116 China The Key Laboratory of Biotechnology on Medical Plants of Jiangsu Province Xuzhou 221116 China

The title compound 1-（4-chlorophenyl）-2-cyano-3-amino-3a-hydroxy-3a,3b,6,7- tetrahydro-benzo[4,5]indene 2, has been synthesized by the reductive cyclization of 2-cyano-3- （4-chlorophenyl）-3-（1-tetralon-2-yl） propionitrile 1 induced by low-valent titanium reagent and its structure was determined by single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group C2/c with a = 28.244（7）, b = 14.401（3）, c = 21.245（3）A,β= 115.71（2）°, V = 7786（3）A^3, Mr= 696.13, Dc = 1.188 g/cm^3, Z = 8,μ（MoKα） = 0.208 mm^-1, F（000） = 2916, R = 0.0783 and wR = 0.2350. X-ray analysis reveals that the five-membered ring （C（7）～C（l l）） adopts an envelop conformation, while the six-membered ring （C（10）～C（14）, C（19）） has a half-chair conformation. Meanwhile, intermolecular H-bond interactions result in the formation of polymer.

关键词： tetrahydrobenzoindene synthesis crystal structure low-valent titanium

Microstructure and tensile properties of A356 alloy with different Sc/Zr additions

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2021年第9期40卷 2514-2522页

作者： Shou-Peng Xu chun-Sheng shi Nai-Qin Zhao chun-Nian He School of Materials Science and Engineering and Tianjin Key Laboratory of Composites and Functional Materials Tianjin UniversityTianjin 300350China Collaborative Innovation Center of Chemical Science and Engineering Tianjin 300072China

Addition of rare earth elements for improving the tensile properties of aluminum alloys has attracted great attention. In this study, a systematic analysis on the microstructure and tensile properties of A356–0.13 Ti alloys with different contents of scandium(Sc) and scandium/zirconium(Sc/Zr) after solution and aging treatment process was carried out. The addition of Sc/Zr into A356–0.13 Ti alloys can greatly refine the grain size and modify the deleterious coarse eutectic Si structure and harmful acicular iron-containing phase morphology. As a result, the maximum value of strength(298 MPa) and ductility(elongation of 8.4%) are acquired by co-addition of Sc/Zr after solution and aging treatment process, which indicates that the tensile properties of A356 alloy are greatly enhanced by the synergistic effect of co-addition of Sc/Zr.

关键词： Aluminum alloys Sc/Zr Tensile properties Solution and aging treatment