Effect of enzyme addition on fermentative hydrogen production from wheat straw

Wheat straw is an abundant agricultural residue which can be used as raw material to produce hydrogen (H₂), a promising alternative energy carrier, at a low cost. Bioconversion of lignocellulosic biomass to produce H₂ usually involves three main operations: pretreatment, hydrolysis and fermentation. In this study, the efficiency of exogenous enzyme addition on fermentative H₂ production from wheat straw was evaluated using mixed-cultures in two experimental systems: a one-stage system (direct enzyme addition) and a two-stage system (enzymatic hydrolysis prior to dark fermentation). H₂ production from untreated wheat straw ranged from 5.18 to 10.52 mL-H₂ g-VS⁻¹. Whatever the experimental enzyme addition procedure, a two-fold increase in H₂ production yields ranging from 11.06 to 19.63 mL-H₂ g-VS⁻¹ was observed after enzymatic treatment of the wheat straw. The high variability in H₂ yields in the two step process was explained by the consumption of free sugars by indigenous wheat straw microorganisms during enzymatic hydrolysis. The direct addition of exogenous enzymes in the one-stage dark fermentation stage proved to be the best way of significantly improving H₂ production from lignocellulosic biomass. Finally, the optimal dose of enzyme mixture added to the wheat straw was evaluated between 1 and 5 mg-protein g-raw wheat straw⁻¹.     

路井凹陷的构造特征与油气远景分析

20世纪80年代末，路井凹陷(又称麻木鸟苏凹陷)开始成为油气勘探的目标。1995年，在额1井首次获得工业油气流，证实该凹陷具备油气生成聚集条件。随后钻探额2井、额3井，均遭失败。为了探索该区下一步的勘探方向，本文从凹陷的构造和沉积演化着手，重点研究了该区的生油层、储层的沉积相带特征和有利的油气聚集带。中下侏罗统大山口群和白垩系麻木鸟苏组为该区主要生油岩系；下白垩统额济纳组为良好储层；燕山运动早期和中期形成的各类局部构造圈闭，均可能成为油气聚集场所；桃西低凸起、麻二号和麻三号构造带是有利的油气聚集带。本文认为该区展示了良好的油气远景。     

SIMULATION OF EDDIES AFFECTED BY TOPOGRAPHY IN A BAROTROPICAL QUASI-GEOSTROPHIC FLUID

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＭｅｓｏ ｓｃａｌｅｅｄｄｉｅｓａｒｅａｃｏｍｍｏｎｄｙｎａｍｉｃｐｈｅ ｎｏｍｅｎｏｎｉｎｔｈｅｏｃｅａｎ ,ｗｈｉｃｈａｌｓｏｐｌａｙａｎｉｍｐｏｒｔａｎｔｒｏｌｅｉｎｍｅｔｅｏｒｏｌｏｇｙ .Ｉｎｔｈｅｍｏｖｅｍｅｎｔｏｆａｔｍｏ ｓｐｈｅｒｅ ,ｔｈｅａｐｐｅａｒａｎｃｅｏｆｂａｒｒａｇｅｈｉｇｈ ｐｒｅｓｓｕｒｅａｎｄｉｎｔｅｒｃｅｐｔｉｖｅｌｏｗ ｐｒｅｓｓｕｒｅｃａｎｐｒｏｄｕｃｅｌａｒｇｅ ｓｃａｌｅｅｄ ｄｉｅｓ;ｌｉｋｅｗｉｓｅ ,ｉｎｔｈｅｍｏｖｅｍｅｎｔｏｆ…     

Tobacco use and other risk behaviors among adolescents in an STD clinic

OBJECTIVE: To test efficacy of murine monoclonal, rabbit polyclonal recombinant equine or human tumor necrosis factor-alpha (rETNF or rHTNF, respectively) antibodies to inhibit native equine tumor necrosis factor (TNF) activity. ANIMALS: 8 and 18 healthy adult horses for parts 1 and 2 of the study, respectively. PROCEDURES: In part 1, supernates from endotoxin-activated peritoneal macrophages were incubated with various dilutions of each rETNF antibody and subsequently tested for TNF activity. Serum was also obtained from a horse 1 hour after infusion with 20 ng of endotoxin/kg of body weight and was incubated with various dilutions of rabbit polyclonal rHTNF antibody. In part 2, 20 ng of endotoxin/kg was infused in horses during a 30-minute period. Fifteen minutes after the endotoxin infusion was initiated, 1 of 3 preparations was infused: 0.1 mg of rabbit polyclonal (rHTNF antibody/kg, 0.1 mg of human IgG/kg, or 500 ml of 5% dextrose. Clinical and hematologic data were collected for 24 hours. RESULTS: Compared with the monoclonal antibody, the rabbit polyclonal rETNF antibody was more effective in inhibiting TNF activity. The 50% effective doses of the murine monoclonal rETNF, rabbit polyclonal rETNF, and rabbit rHTNF antibodies were 1.8, 0.8, and 0.6 micrograms of antibody/ml, respectively. In part 2, endotoxin infusion resulted in significant alternations in all variables; however, differences among treatment groups were not significant. CONCLUSIONS AND CLINICAL RELEVANCE: Although murine monoclonal and rabbit polyclonal rETNF or rHTNF antibodies are capable of inhibiting native equine TNF activity in vitro, when given after initiation of endotoxemia, administration of 0.1 mg of rabbit polyclonal rHTNF/kg does not alter the response to infusion of endotoxin.     

射流管电液伺服阀专题讲座

第三章射流管伺服阀的污染控制概述 现代的液压控制系统越来越多地采用伺服控制和比例控制阀,这些部件同制造过程和最终产品质量的控制密切相关,而保证液压流体的清洁度和化学成分是维持液压系统工作的关键,其中阀滤器的适当选取和工作环境影响清洁度,因此在过滤方面应对阀、阀的设计、回路布局以及工作环境加以认真考虑.如此,才能在多数恶劣的环境中获得高的可靠性和长的使用寿命.     

碱性药芯焊丝的四种设计类型的比较

全面研究了药芯焊丝的碱性渣系，归纳出四种可能的设计类型，并对它们进行了比较研究。     

NUMERICAL SIMULATION OF THE TIDAL MOTION AND SUSPEND EDSEDIMENT TRANSPORT IN THE RADIAL SANDBANK AREA OF THE SOUTHERN YELLOW SEA

A coupled 2-D numerical model for hydrodynamic-sediment transport was established and applied to simulate the tides, tidal currents and sediment movement in the submarine Radial Sandbank area of the southern Yellow Sea.With a high-resolution topography dataset used in the model,the simulation reproduced a fine-structured current field and erosion-siltation distribution. The modeled results show that,in the area of Radial Sandbanks, reversing tidal current and seabed erosion occurs within troughs while tidal current with more rotary feature and deposition occurs above sandbanks,which indicates the tidal-induced formation of the Radial Sandbanks. During a tidal period, associating with the variation of current speed, erosion alternates with siltation. The seabed deformation depends on the relative strength of erosion and siltation in a tidal period.     

图像处理在地球物理学中的应用

地球物理资料以图像的形式表达，不仅直观形象，还能应用图像处理技术对其进行处理和分析，提高其解决地球物理、地质问题的能力。文中介绍了几种地球物理图像的表达方式，对图像处理在地球物理领域的应用情况作了综述，指出目前在地球物理数据处理中应用广泛的是图像增强、重建和分析技术，基于图像处理的多源信息的综合分析是地球物理研究的趋势；考虑到地球物理图像与一般意义上图像的差异，对图像处理过程中应该注意的问题给出某些认识；结合在地球物理研究中日益渗透的地理信息系统技术，对图像处理在地球物理中的应用作了展望。     

缸体材料激光处理后的残余应力测试及分析

柴油机缸套在激光处理中采用不同的扫描排布方式，在磨损试验中其磨损量差异很大，本文从应力角度证实了激光处理网纹排布方式的不合理性。     

THE RESPONSES OF THE THIRD GENERATION OF IAP/LASG OCEANIC GCM TO DIFFERENT EXTERNAL FORCING

1 .　ＩＮＴＲＯＤＵＣＴＩＯＮＴｈｅａｎｎｕａｌｍｅａｎｃｌｉｍａｔｏｌｏｇｙ ,ｓｅａｓｏｎａｌｃｙｃｌｅａｎｄｉｎｔｅｒａｎｎｕａｌｖａｒｉｅｔｉｅｓｃｈａｒａｃｔｅｒｉｓｔｉｃｏｆｓｅａｓｕｒｆａｃｅｔｅｍｐｅｒａｔｕｒｅ (ＳＳＴ)ａｎｄｕｐｐｅｒ ｏｃｅａｎｈｅａｔｃｏｎｔｅｎｔａｓｗｅｌｌａｓｔｈｅｉｒｒｅｌａｔｉｏｎｓｈｉｐｉｎＬ30Ｔ63,ｔｈｅｔｈｉｒｄｇｅｎ ｅｒａｔｉｏｎｏｆｔｈｅｏｃｅａｎｉｃ ｇｅｎｅｒａｌｃｉｒｃｕｌａｔｉｏｎｍｏｄｅｌ(ＧＣＭ )ｄｅｖｅｌｏｐｅｄｉｎｔｈｅＳｔａｔ…