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Search Results: 1 - 10 of 13898 matches for " 赖晨欢 "
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纸浆浓度及分批补料对里氏木霉产纤维素酶的影响
饶庆隆,杭志喜,,余世袁*
南京林业大学学报(自然科学版) , 2008, DOI: 10.3969/j.jssn.1000-2006.2008.03.013
Abstract: <正>以山地杨树人工林为对象,研究了不同覆盖量和覆盖材料对杨树根际土壤磷动态的影响。结果表明:覆盖后杨树根际全磷含量随着覆盖量的增加而增加,2.5、5.0、7.5kg/m2覆盖处理的杨树根际土壤全磷量分别比ck高10.77%、13.85%和52.31%;4种覆盖材料间差异不大,但均大于对照。覆盖能有效提高杨树根际土壤有效磷含量,覆盖量越大,效果越明显;不同覆盖材料对根际土壤有效磷的影响有较明显的差异,对杨树根际土壤磷动态变化的影响与不同覆盖厚度处理结果相似,覆盖以后杨树根际土壤全磷含量及有效磷含量有先下降后上升的趋势。
茶皂素对稀酸预处理锯木屑酶水解的影响
杨博,,林子贺,谢佳笑,宋向阳
- , 2018, DOI: 10.13360/j.issn.2096-1359.2018.06.013
Abstract: 高效纤维素酶水解是木质纤维原料生物炼制的关键。通过添加表面活性剂减少纤维素酶在物料上的非特异性吸附是提高酶水解效率的有效方法之一。然而,目前有关天然表面活性剂在木质纤维素酶水解中的应用鲜有报道。该研究介绍了一种从油茶饼废弃物中提取的天然表面活性剂――茶皂素在木质纤维素酶水解中的应用,并探究其对预处理物料酶水解的促进机制。结果表明,在稀酸预处理锯木屑酶水解中,茶皂素最适添加量为0.075 g/g。当纤维素酶用量为20~80 U/g时,添加0.075 g/g的茶皂素使得稀酸预处理锯木屑72 h葡萄糖得率提高了10.3%~32.5%。同时,添加茶皂素可显著提高72 h酶水解上清液中的残余纤维素酶活力,其中内切葡聚糖酶和滤纸酶活分别提高了6.6和3.0倍。由此推测,天然表面活性剂茶皂素可减少纤维素酶在物料上的非特异性吸附,从而提高预处理物料酶水解效率。此外,添加茶皂素相对含量为0.075 g/g的油茶饼茶皂素粗提液时,稀酸预处理锯木屑葡萄糖得率同样提高了33.3%。综上所述,茶皂素作为一种天然表面活性剂用于木质纤维生物炼制具有一定的应用前景,为油茶饼废弃物开拓了新的利用途径。
Cellulase hydrolysis of cellulose is a dominating process in lignocellulose biorefinery. To achieve the highly efficient enzymatic hydrolysis, it is necessary to conduct the pretreatment on lignocellulosic materials prior to the enzymatic hydrolysis. The pretreatment on lignocelluloses can destroy the recalcitrant structure of the lignocellulosic matrix, and thus increase the cellulose accessibility. However, the residual lignin after pretreatment still hindered the enzymatic hydrolysis of lignocellulosic materials by physically blocking and non-productively binding cellulases. The addition of surfactant is considered as one of the effective methods to improve the enzymatic hydrolysis, due to its role of reducing the non-productive adsorption of cellulase. Tea saponin, a kind of natural surfactant and easily obtained from oil tea cake waste, was applied in the enzymatic hydrolysis of dilute acid pretreated wood sawdust in this paper. The results showed that the addition of tea saponin could enhance the efficiency of enzymatic hydrolysis of dilute acid pretreated wood sawdust. The optimal loading of tea saponin was 0.075 g/g(based on dry weight of cellulose). Within the cellulase dosage range of 20-80 U/g cellulose, the addition of tea saponin increased the 72 h glucose yield of dilute acid pretreated wood sawdust by 10.3%-32.5%. Meanwhile, the addition of tea saponin obviously increased the residual activities of cellulase in the supernatant of 72 h hydrolysis. The endo-glucanase activity and filter paper activity respectively increased 6.6 and 3.0 fold. This indicates that the addition of tea saponin can improve the enzymatic hydrolysis of dilute acid pretreated wood sawdust by reducing the non-productive adsorption of enzyme. Moreover, the addition of the crude tea saponin solution(relative loading of 0.075 g/g based on dry weight of cellulose)from oil tea cake increased the glucose yield of enzymatic hydrolysis by 33.3%. It suggested that tea saponin could be used as a natural surfactant to promote the enzymatic hydrolysis of lignocellulosic materials
搅拌转速和通风量对里氏木霉发酵β-甘露聚糖酶的影响
谢益晖,黄曹兴,李鑫,,余世袁,勇强
- , 2017, DOI: 10.13360/j.issn.2096-1359.2017.06.016
Abstract: 发酵液中溶解氧浓度是好氧发酵过程中反映氧传质效率的综合指标,维持发酵液适宜的溶解氧浓度是实现好氧发酵成功的关键所在,搅拌转速和通风量是影响发酵液溶解氧浓度的重要参数。笔者研究了在3 L发酵罐中搅拌转速和通风量对里氏木霉发酵合成β-甘露聚糖酶的影响。试验结果表明,里氏木霉发酵β-甘露聚糖酶时搅拌转速对氧传质效率的影响大于通风量。以质量浓度为1 g/L的葡萄糖和21.95 g/L的微晶纤维素为碳源发酵合成β-甘露聚糖酶,当搅拌转速450 r/min、通风量0.3 m3/(m3?min)时,发酵过程中溶解氧浓度保持在20%以上,发酵120 h,β-甘露聚糖酶活力、β-甘露糖苷酶活力和菌体质量浓度达到最大值3.92 U/mL,0.033 U/mL和6.56 g/L。因此,发酵过程中溶解氧浓度维持在20%以上可获得较高的β-甘露聚糖酶活力。
Trichoderma reesei is a kind of microorganism that can secrete enzymes(cellulase, hemicellulase, β-mannanase etc.)by aerobic fermentation with carbon sources, nitrogen source, and nutritive salt.For aerobic fermentation, the concentration of dissolved oxygen of fermentation broth is a comprehensive index to reflect the oxygen transfer efficiency.Meanwhile, maintaining a suitable concentration of dissolved oxygen in the fermentation broth is important to aerobic fermentation.During the fermentation process, the agitation speed and the aeration rate are both important parameters for oxygen transferring.In this study, the effects of the agitation speed(100-500 r/min)and the aeration rate(0.2-1.0 m3/(m3?min))on the production of β-mannanase by T.reesei were investigated in a 3 L fermentor.Specifically, the β-mannanase activity, β-manosidase activity and biomass were investigated when different agitation speed and aeration rate were carried out.The results showed that both the increased agitation speed and aeration rate could lead to higher oxygen transfer efficiency.However, the effect of agitation speed on oxygen transfer efficiency was greater than that of aeration rate.With the fermentation conditions for 1 g/L of glucose and 21.95 g/L of microcrystalline cellulose as carbon sources at 450 r/min of agitation rate and 0.3 m3/(m3?min)of aeration rate for 120 h, the dissolved oxygen tension can be remained above 20% during fermentation process.Accordingly, T.reesei could produce the β-mannanase with maximal β-mannanase activity, β-manosidase activity and biomass of 3.92 U/mL, 0.033 U/mL and 6.56 g/L, respectively.Therefore, it can be concluded that higher β-mannanase activity can be obtained when the dissolved oxygen tension is maintained at more than 20% in the fermentation process
稀硫酸预处理对毛竹竹黄木质素结构的影响
黄曹兴,何娟,闵斗勇,,余世袁,勇强
- , 2016, DOI: 10.13360/j.issn.2096-1359.2016.01.011
Abstract: 以毛竹竹黄为原料,研究其木质素在稀酸预处理过程中的结构变化。依据Bj?rkman的方法分离纯化得到竹黄和稀酸预处理竹黄的磨木木质素,采用红外光谱(FT-IR)和核磁共振定量13C谱对两个木质素样品结构进行分析。FT-IR和定量13C谱图表明:在酸性条件下,竹黄木质素紫丁香基单元中醚化的联接键发生断裂,S/G比值由1.3降低为1.1。木质素在稀硫酸预处理过程中发生缩合反应,主要发生在愈创木基单元上。木质素芳环上C―O键含量由196.1/100C9降低为187.7/100C9,C―H键含量由219.4/100C9降低为205.7/100C9, C―C键含量由179.6/100C9提高为190.3/100C9,缩合度由31.4%提高为35.2%。
The effect of dilute acid pretreatment on the lignin structure of Moso bamboo inner skin was investigated. The bamboo inner skin ball-milled lignins(MWLs)were isolated before and after dilute sulfuric acid pretreatment, according to the isolation method developed by Bj?rkman. The structures of the MWLs were characterized by fourier transform infrared spectroscopy(FT-IR)and nuclear magnetic resonance(NMR). The 13C-NMR spectra showed that the etherified linkages in syringyl units were depolymerized during the acid pretreatment. After pretreatment, the S/G ratio of lignin was reduced from 1.3 to 1.1. Meanwhile, some lignins were condensed during the acid pretreatment, inducing the condensation degree increased from 31.4% to 35.2%. The amount of C―O and C―H linkages in the lignin were reduced from 196.1/100C9 and 219.4/100C9 to 187.7/100C9 and 205.7/100C9, respectively. While, the C―C linkages in the lignin were increased from 179.6/100C9 to 190.3/100C9
田菁来源半乳甘露低聚糖对青春双歧杆菌的增殖
陆?F妍, , 杨磊, , , , 周梦怡, 奚晓桐, 余世袁, , 勇强
- , 2017, DOI: 10.13360/j.issn.2096-1359.2017.03.011
Abstract: 田菁是被广泛应用的盐碱地改良先锋植物,半乳甘露聚糖是田菁种子的主要成分。半乳糖、甘露糖和半乳甘露低聚糖为半乳甘露聚糖酶法完全和不完全水解产物。为揭示不同分子质量半乳甘露聚糖不完全降解产物的生物学功能差异,笔者研究了半乳糖、甘露糖和不同分子质量分布的半乳甘露低聚糖对青春双歧杆菌(Bifidobacterium adolescentis)的增殖作用及其代谢产物。青春双歧杆菌分别以3 g/L(质量浓度)半乳糖和甘露糖为碳源培养24 h,糖利用率分别为99.67%和72.00%,菌体质量浓度从初始的0.04 g/L分别增殖到1.82和0.39 g/L,生成的总短链脂肪酸(乙酸、乳酸和丙酸)质量浓度分别为6.76和3.02 g/L。不同分子质量分布的半乳甘露低聚糖能有效增殖青春双歧杆菌,半乳甘露低聚糖平均分子质量越低,对青春双歧杆菌的增殖作用越强。青春双歧杆菌以3 g/L,分子质量分布为5~10,2~5和≤2 ku的半乳甘露低聚糖为碳源培养24 h,半乳甘露低聚糖利用率分别为59.00%,61.67%和86.33%,青春双歧杆菌菌体质量浓度从初始浓度的0.04 g/L分别增殖到0.51,0.79和1.71 g/L。青春双歧杆菌以分子质量≤2 ku的半乳甘露低聚糖为碳源培养24 h,代谢产物乙酸、乳酸和丙酸的质量浓度分别为4.14,2.48和0.81 g/L。
Sesbania cannabina is widely used as a pioneer plant in improving saline alkali land, and galactomannan is the main component of S. cannabina seeds. Galactose, mannose and galactomanno-oligosaccharides are complete and incomplete degradation products of galactomannan. In order to reveal the differences in the biological functions of incomplete degradation products of galactomannan with different molecular weight, galactose, mannose and galactomanno-oligosaccharides with different molecular weight distribution were used as carbon source for in vitro proliferation of Bifidobacteria adolescentis, and the main metabolites were analyzed. When 3 g/L of galactose and mannose was used as carbon source for proliferation of B. adolescentis, the sugar consumption were 99.67% and 72.00%, respectively, the cell concentration increased from 0.04 g/L(initial concentration)to 1.82 and 0.39 g/L, and the production of total short chain acids(acetic acid, lactic acid and propionic acid)were 6.76 and 3.02 g/L, respectively. The galactomanno-oligosaccharides with different molecular weight distribution could proliferate B. adolescentis effectively, and the lower molecular weight of the galactomanno-oligosaccharides, the greater effect on the growth of the B. adolescentis. When 3 g/L galactomanno-oligosaccharides with the molecular weight distribution of 5-10 ku, 2-5 ku and the molecular weight less than 2 ku were used as carbon source for proliferation of B. adolescentis for 24 h, respectively, the consumption of galactomanno-oligosaccharides were 59.00%, 61.67% and 86.33%, the B. adolescentis concentration increased from initial concentration of 0.04 g/L to 0.51, 0.79 and 1.71 g/L, respectively. When 3 g/L galactomanno-oligosaccharides with the molecular weight less than 2 ku was used as carbon source for proliferation of B. adolescentis for 24 h, the metabolites concentration of acetic acid, lactic acid and propionic acid were 4.41, 2.48 and 0.81 g/L, respectively
不同预处理对毛竹木质素抗氧化性的影响
黄曹兴,房伶晏,,唐硕,梁辰,李鑫,勇强
- , 2018, DOI: 10.13360/j.Issn.2096-1359.2018.03.013
Abstract: 采用核磁共振技术(2D-HSQC NMR和定量31P NMR)分析毛竹木质素经稀硫酸法和硫酸盐法预处理后官能团含量和结构单元类型比例变化,并对预处理前后木质素抗氧化性能(1,1-二苯基-2-三硝基苯肼(DPPH)和超氧阴离子自由基清除能力)进行评价。核磁共振分析结果表明,毛竹木质素(MWLr)经稀硫酸法和硫酸盐法预处理(MWLa和KL),紫丁香基单元摩尔含量比例从50.6%提高至68.8%和72.2%,相连接的麦黄酮结构发生降解,脂肪族羟基、酚羟基和羧基质量分数均增加。抗氧化性结果表明,MWLr,MWLa和KL对DPPH自由基最大清除能力为79.59%,75.57%和77.69%,对超氧阴离子自由基最大清除能力为81.15%,47.27%和74.53%。稀酸和硫酸盐法预处理降低毛竹原本木质素抗氧化能力可能是由于木质素结构中麦黄酮被降解和紫丁香基结构质量分数比例增加导致。
In this study, lignins in Moso bamboo and acid-pretreated bamboo were isolated according to the method developed by Bjorkman, termed as MWLr and MWLa, respectively. Lignin in black liquor of pretreated bamboo by kraft pulping was precipitated by acid and termed as KL. Then, the obtained lignins(MWLr, MWLa, and KL)were characterized by 2D heteronuclear single quantum correlation nuclear magnetic resonance(2D-HSQC NMR)and quantitative 31P NMR to analyze the effects of different pretreatments on the functional groups and types of lignin units in the resulting lignin. Meanwhile, the performance of above obtained lignins on the scavenging of superoxide anion free radical and 1,1-diphenyl-2-picryl-hydrazyl(DPPH)radical were investigated. Results from the NMR analysis showed that the percentage of syringyl units in bamboo lignin increased from 50.6% to 68.8% and 72.2% after it was pretreated by acid and kraft pulping, respectively. In addition, the pretreatments resulted in degradation of tricin and increase in the amounts of alphatic hydroxyl groups, phenolic hydroxyl groups, and carboxylic acid groups in obtained lignin samples. It showed that the capabilities of MWLr, MWLa, and KL to scavenge DPPH radical were up to 79.59%, 75.57%, and 77.69%, respectively. For superoxide anion free radical, the highest scavenging rates were 81.15%, 47.27%, and 74.53% that achieved by MWLr, MWLa, and KL, respectively. These results indicated that the antioxidant activity of the obtained lignin decreased after it was pretreated by acid or kraft pulping process. The probable reasons for this result might be due to the degradation of tricin in lignin and the increased percentage of syringyl units in the lignin
三峡船闸运行调度中的多属性决策问题
 炜,齐 
控制与决策 , 2002,
Abstract: 提出三峡船闸运行中的多属性决策问题,并具体分析了决策矩阵规范化、各属性权重确定和决策方案筛选。最后采用该方法对三峡过闸船只进行多次试排,结果表明,若将该方法应用于实际系统,将达到令人满意的效果。
海洋钻修机模块载荷工况分析
Analysis on Load Project of Ocean Well Servicing Module
 [PDF]

程鹏, 李全星, 刘刚强, 颜岁娜, , 杨鹏
Mechanical Engineering and Technology (MET) , 2015, DOI: 10.12677/MET.2015.42017
Abstract:
以QHD32-6项目中研制的2250KN海洋钻修机模块为例,ANSYS有限元计算进行工况分析。对各工况分析计算中涉及到的规范及要求进行详解,并对计算中可能出现的问题进行分析,并形成有效且合理的工况分析载荷列表,为有限元计算提供核心依据。
Aiming at 2250kN ocean well drilling and servicing desktop module which is made during QHD32-6 project, the article analyzes working condition with ANSYS finite element calculation, explains the specifications and requirements which are involved in the analysis and calculation of each working condition, and construes the possible problems in calculation, then forms reliable and reasonable load case analysis lists that provide the core basis for the following finite element calculation.
电可调非致冷红外探测原理
,建军,李宏伟,李明燃,刘黎
红外与毫米波学报 , 2015,
Abstract: 传统的红外光谱探测技术能够提供丰富的光谱信息,应用广泛,但该技术同时也存在一定局限性,如很难同步实现探测器小型化和探测波段实时调节等方面的要求.提出了一种基于电可调表面等离子体谐振吸收的新型FET红外探测器结构.基于电磁场理论分析了结构参数对红外光学吸收的影响,并通过结构参数的优化使吸收结构对特定红外波段的吸收率达到90%以上.栅压变化时VOx热敏层中载流子的浓度分布和折射率均发生变化,显示该器件具有明显的电可调光谱吸收特性.借助于这种FET结构,非制冷红外探测器将具有片上可调光谱探测能力,同时具有易于阵列化特点,为微小型可配置光谱成像探测器件提供了一条思路.
化学氧碘激光器尾气主动冷却技术试验
陈振华,任泽斌,赵波,
强激光与粒子束 , 2014,
Abstract: ?使用主动冷却技术降低化学氧碘激光器(coil)尾气的温度,是提高引射式压力恢复系统引射效率的一项关键技术。采用理论计算和数值模拟的方法,得出了满足技术指标要求的冷却器系统设计参数,并研制了一套以管翅式热交换器、液氮循环汽化提供制冷量的coil尾气主动冷却试验装置。与激光器的对接试验结果表明,在coil出光60s试验中,热交换器可以使尾气温度从590k降低到160k,出口截面温度不均匀度小于21k,经过热交换器的气流总压损失小于100pa。
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