培养条件对绿色木霉发酵生产纤维素酶的影响

考察了不同培养条件对绿色木霉发酵生产纤维素酶的影响。结果表明，当以5．0g／L硫酸盐纸浆作为碳源，纤维素酶活值为27．956IU／mL，其值是以纤维素作为碳源时的2．19倍。当培养基中以2．0g／L蛋白胨为唯一氮源时，纤维素酶值活可达58．461IU／mL。当培养基中添加2．0g／L葡萄糖，可以最大限度地提高纤维素酶的产量。另外，菌丝体的最佳接种量为10％。     

船舶机舱含油污水用膨胀石墨/活性炭复合吸附剂试制

以蔗糖为碳源,以磷酸为活化剂,在浸渍比(磷酸质量/蔗糖质量)2.5、活化温度550℃下制备活性炭,在膨化温度900℃和膨化时间25s下制备膨胀石墨,复合膨胀石墨/活性炭吸附剂,并测试膨胀石墨密度0.02g/cm3～0.05g/cm3、乳化油流率0.07mL/s～0.6mL/s、吸附柱高度10mm～30mm时的吸油效果。结果表明:在吸附柱高度20mm、乳化油流率小于0.4mL/s时,0.1‰的乳化油经膨胀石墨成型密度为0.03g/cm3的复合吸附剂过滤后的含油量可低于0.005‰;膨胀石墨成型密度0.03g/cm3、乳化油流率0.4mL/s时,吸附柱高度20mm的处理污水含油量小于0.015‰的总处理量为10.35L,即单位体积吸附剂的乳化油处理量为0.3255L/cm3。因此,应根据船舶机舱油水分离器的技术要求,优化复合吸附剂含油污水处理流程。     

一株产蛋白酶植物内生菌的分离、鉴定及产酶条件研究

采用明胶平板筛选法从植物防风的根中分离得到一株高产蛋白酶的内生菌株FFR3.结合生理生化特性和16S rDNA序列分析,初步鉴定此菌株为类芽孢杆菌Paenibacillus sp..以胞外蛋白酶活力为指标,对内生细菌FFR3的产酶培养条件进行初步研究.结果表明:5 g/L葡萄糖和7.5 g/L酵母浸膏是菌株生长产酶的较适碳源和氮源;无机盐MgSO_4·7H_2O、KH_2PO_4和FeSO_4·7H_2O浓度分别为3、5和0.1 g/L时有利于胞外蛋白酶的产生.菌株在发酵培养条件为2%接种量、50 mL/250 mL装液量、pH 7.0、转速180 r/m,温度37℃时,发酵48 h可获得较高的酶产量,蛋白酶活力可达633.19 U/mL,较初筛时的酶活力提高15.94倍.     

乳源抗菌肽的抑菌活性及其影响因素

以大肠杆菌和金黄色葡萄球菌为实验菌,研究了乳源抗菌肽的抑菌活性,以及pH值、温度、热处理时间、胃蛋白酶水解和离子强度等不同因素对乳源抗菌肽抑菌活性的影响.结果表明:乳源抗菌肽对金黄色葡萄球菌的最小抑菌浓度为4μg/mL,对大肠杆菌的最小抑菌浓度为8μg/mL;乳源抗菌肽在pH值为7.0～8.0时的抑菌活性最高;在60℃以上时,随着温度的升高及加热时间的延长,乳源抗菌肽抑菌活性逐渐降低;胃蛋白酶能够部分水解乳源抗菌肽,降低乳源抗菌肽的抑菌活性;当NaCl浓度为0～100 mmol/L,CaCl2浓度为0～5.0 mmol/L时,离子强度越大,乳源抗菌肽的抑菌活性越低.     

活性氧化铝除磷吸附剂的试验研究

本研究以活性氧化铝为吸附剂,用静态实验方法,对活性氧化铝进行吸附除磷性能评价。实验结果表明,r=AL2O3最佳投加量为0.5 mg/50 mL,最适宜的pH值是2.8~3.8,吸附平衡时间为2 h,最大吸附容量为9.4 mg/g,当磷的初始浓度为10 mg/L时去除率最高。     

超声波辅助纤维素酶法提取桑枝皮ACE抑制剂及其分子量分布研究

为探讨桑枝皮的高效利用价值,采用超声波辅助纤维素酶法从桑枝皮中提取了血管紧张素转化酶抑制剂,优化了201×7阴离子树脂分离桑枝皮ACE抑制剂的条件,运用液相色谱-质谱联用技术分析了其分子量分布.结果表明,超声波处理可提高纤维素酶的活性,超声波辅助纤维素酶处理可有效促进ACE抑制剂的释放;201×7阴离子交换树脂最佳分离条件为:上样量20 mL,上样速度1.0 mL/min,洗脱液为2.0 mol/L的NaCl溶液.桑枝皮ACE抑制剂的最大吸收峰为225nm,其分子量在107~888 Da之间,其中216 Da组分的含量最高.     

一株利用纤维素产紫杉醇菌株BJ-11的分离鉴定

从红豆杉中分离到206株内生真菌,经薄层层析(TLC)和高效液相色谱(HPLC)检测,确定有一株真菌(编号BJ-11)可以产生紫杉醇.利用蔗糖为碳源发酵10 d,紫杉醇产量可达127.20 μg/L;而且该菌能够利用纤维素作为唯一碳源生产紫杉醇,发酵16d产量可达110.3 μg/L,有望大大降低发酵制备紫杉醇生产的成本.该菌株生长快速、紫杉醇产生时间早(2d)、孢子产量大,是一株优良的紫杉醇产生菌.经形态鉴定,BJ-11为炭黑曲霉.     

昆虫激素体外调节家蚕滞育激素受体基因的表达

为了深入研究家蚕滞育的分子机理,从家蚕基因组中扩增了1395 bp和972 bp 2个不同长度的滞育激素受体基因Bmdhr启动子片段,以pGL3.0 Basic为载体,分别构建荧光素酶报告质粒,利用家蚕细胞瞬时表达系统分析其转录活性以及昆虫保幼激素类似物（JHA）、蜕皮激素（20-OH-ecdysone）和滞育激素（DH）对其活性的影响．结果表明：1395 bp的Bmdhr启动子活性显著低于972 bp的Bmdhr启动子,这说明Bmdhr启动子在-941～-1364 nt区间存在负调控元件．JHA浓度为2,4,6μg/mL时,极显著地增强启动子活性;浓度为1μg/mL时活性显著减弱,而为8μg/mL时则活性极显著减弱．20-OH-ecdysone对Bmdhr启动子活性的影响具有剂量效应,低浓度（1,2μg/mL）时显著增强启动子活性;浓度为4μg/mL时,启动子的活性显著减弱;但当浓度继续升高时,启动子活性又极显著增强．DH对Bmdhr启动子活性的影响同样具有剂量效应,其浓度为10～40 nM时,显著增强启动子活性;而当其浓度达到60 nM时,启动子活性变化不显著．     

不同理化因子组合对长春花悬浮培养的研究

实验研究了不同种类、不同浓度的植物生长调节物质组合和其他四种理化因子对长春花悬浮培养细胞生长的影响。以前的实验结果表明：单因子以2,4-D效果最好。其中以2,4-D的最佳浓度为0．5mg/L。而本次实验的结果表明：组合因子比单因子更有利于细胞的生长,以0．5mg/L NAA 0．5mg/L 2,4-D 2．0mg/L 6-BA为最佳。在其它的四种理化因子中,1/2MS、MS和B5培养基有利于细胞的生长。蔗糖的最佳浓度为30g/L；葡萄糖在研究范围内随着浓度的增加,生长速度也在增加。最适于长春花的PH值为5．0-5．4。     

NaOH含量对AZ91D镁合金微弧氧化膜层微观结构和耐蚀性的影响

在由15 g/L Na2SiO3、12 g/L NaAlO2、3 g/L Na2B4O7、5 mL/L C3H8O3、5 g/L C6H5Na3O7及1~4 g/L NaOH组成的硅铝复合电解液中,利用微弧氧化技术在AZ91D镁合金基体上制备了一系列陶瓷膜层.利用扫描电镜、膜层测厚仪分别研究了陶瓷膜层的微观结构及厚度;采用全浸泡实验和交流阻抗实验测试了膜层在3.5%NaCl溶液中的耐蚀性能.结果表明：随着NaOH含量的增加,微弧氧化过程中的起弧电压和终止电压均呈线性下降;膜层的耐蚀性随着NaOH含量的增加先提高后降低,膜厚的变化趋势与其耐蚀性的变化趋势基本一致;NaOH含量的变化主要影响膜层内部致密层的耐蚀性能;当NaOH含量为2 g/L时,膜层最厚,膜层较致密,因而具有较好的耐蚀性能.     

微波活性炭处理高浓度苯酚洗舱废水的研究

文章考察了活性炭吸附-微波再生技术对船舶化学品洗舱废水的处理效果。结果表明,微波再生不仅可以恢复活性炭的吸附效果,而且可以提供活性炭的吸附容量,经微波再生后活性炭的吸附容量由原来的196.4 mg/g增加到271.1 mg/g;微波再生后活性炭比表面积由原来的746.1 m2/g增加到888.4 m2/g,累积孔体积由原来的0.37 cm2/g增加到0.42 cm2/g;微波再生后活性炭羧基数量明显降低,很大程度上阻碍了水分子簇的形成,促使有机物容易扩散到活性炭的微孔中,进一步微波对活性炭的再生作用。     

Benthic community and food web structure on the continental shelf of the Bay of Biscay (North Eastern Atlantic) revealed by stable isotopes analysis

The North Bay of Biscay continental shelf is a major French demersal fishery, but little was known on the trophic food web of its benthic communities. In order to determine the benthic trophic web, the objectives of this study are to describe the macro- and megafaunal benthic community structure (species richness, abundance and biomass) and to establish the trophic pathways (food sources and trophic levels) by applying carbon and nitrogen stable isotopic analysis to the main benthic and demersal species (invertebrates and fish). Two distinct benthic communities have been identified: a muddy sand community within the central part of the bay, and an outer Bay of Biscay Ditrupa sand community of higher species richness, abundance and biomass than the muddy sand community. Deposit-feeders, suspension feeders and predators, distributed in three main trophic levels, dominate both communities. Large differences in stable carbon ratio values within the primary consumers provide evidence of two different food sources: i) a pelagic food source made up of recent sedimenting particulate organic matter on which zooplankton and suprabenthos feed and ii) a benthic detrital food source supplying deposit feeders and partly benthic suspension feeders. Differences in isotopic signatures were also observed within the upper trophic levels that allowed estimation of the contribution of each food source component to the diet of the upper consumers. Finally, the use of stable isotopic composition together with the species' feeding strategy allow identification of the main differences between the trophic functioning of the two benthic communities and highlight the importance of the role of detrital pathways in the carbon cycling within the continental shelf benthic trophic web.     

螺旋藻生产中两种碳营养源的对比研究

在螺旋藻工业化生产中,通常采用NaHCO3作为碳营养源。本实验以极大螺旋藻作为实验材料,分别采用NaHCO3和CO2作为碳营养源,研究培养过程中螺旋藻的生长速率、培养液的pH值变化和螺旋藻体的形态,探索降低螺旋藻生产成本的方法。实验结果表明:利用CO2来代替NaHCO3作为螺旋藻生产的碳营养源,既可以大幅度地降低螺旋藻生产成本,又有利于培养液维持较为稳定的pH值,使螺旋藻能够保持良好的生长状态,从而延长培养液使用期限。     

航运市场中的牛鞭效应研究

揭示了航运市场中存在的牛鞭效应。结合航运产品的特点及H.L.Lee对牛鞭效应的研究,分析了对航运产品需求的预测、船舶建造周期、批量运输及运输的不平衡性、运输价格的波动、定量供应与短缺博弈是产生航运市场牛鞭效应的主要原因,并由此提出了相应的对策框架。     

舰船交流岸电电源剖析

本文基于对舰船交流岸电电源现况的分析,指出了现今我国绝大部分岸电电源存在的主要问题:一是交流岸电电源采用三相四线制,而舰船电网电源采用三相三线制,两者线制不匹配;二是交流岸电电源没有稳压装置,不适应舰船电网品质要求.针对上述问题,作者进行了理论分析,并提出了解决方案,为舰船交流岸电电源的设计与建造提供了依据.     

本征值问题和可视化技术在电磁场计算中的应用

齐次边界条件或周期性边界条件下的Laplace场构成Sturm-Liouville型本征值问题。求解本征值问题可得一系列的本征值和对应的本征函数。由这些本征函数构成了对应的Laplace边值问题的级数通解。揭示了用于计算电磁场问题的新型等效源方法（包括圆形等效源方法、矩形等效源方法和矩形－圆形等新源混合算法）和本征值问题之间的内在联系，也即阐明了本征值问题是新等效源方法的理论基础。应用模拟电荷法、多极子法、多极理论和新型等效源方法等方法求解计算电磁场时，有关参数（诸如模拟电荷、内外极或者等效源的数目和位置安排，尤其是模拟电荷电量的大小、内外极的次数或者等效源的阶数等）的选择问题是影响这些方法应用的瓶颈。在计算过程中综合应用解的图形显示和校核点处的计算值的误差大小来确定有关参数，既可以确保解的正确性，又可以极大地提高计算效率和计算精度。     

压力源微机伺服系统的研制

工程项目的建设离不开大量岩土试验数据的支撑,在常规的室内岩土试验方法中,三轴剪切试验是测试岩土体抗剪强度的一种非常重要的试验方法。压力源微机伺服系统是一种可受计算机控制、由步进电机驱动的精密水压力发生器,主要应用于三轴剪切试验中围压、反压与体积变化的精确控制与量测,还可作为独立恒压源以取代常规的室内试验压力源,如砝码、空压机及渗透水头等。对比试验结果表明,压力源微机伺服系统性能稳定,提高了三轴剪切试验中压力与体积变化的量测精度,具有自动化程度高、灵敏度高、响应速度快等特点。     

海洋工程用铝合金表面微弧氧化膜的耐腐蚀性能

为了制备性能良好的微弧氧化膜层,以提高海洋平台用2Al2铝合金的耐磨性和耐腐蚀性。本实验采用微弧氧化技术,将不同浓度的MoS2颗粒（0 g/L、1 g/L、2 g/L、4 g/L、6 g/L和8 g/L）添加到电解液中,在2Al2铝合金表面制备微弧氧化膜层。通过扫描电子显微镜和光学显微镜对复合镀层的微观形貌、组织结构进行分析;采用摩擦磨损试验、电化学腐蚀试验等实验方法分析了镀层的耐磨性和耐腐蚀性能。实验结果表明,随着纳米MoS2颗粒含量的增加,陶瓷层表面微孔尺寸减小,微孔数量增加,并且孔洞的分布更加均匀,致密度得到了很大的提高,且膜层厚度随着纳米MoS2颗粒含量的增加先增后减;添加纳米MoS2颗粒后,使得膜层摩擦系数降低,并且基本稳定在0.45左右;当纳米MoS2颗粒含量为4g/L时,陶瓷层的耐腐蚀性能最好。     

中速三体船型PCC的可行性研究(英文)

In the present paper, a new trimaran Pure Car Carrier (PCC) is proposed and a feasibility study on the ship is carried out. In this study, first, the effective horse power (EHP)/car of the PCC running in still water is predicted. By comparing the predicted EHP/car with that of a conventional mono-hull PCC, it is found that the trimaran PCC is superior to the conventional mono-hull PCC at rather higher speed. As ship speed increases, the reduction of the resistance of the trimaran is bigger. It is also found that at common service speed of PCCs, the EHP/car of a small PCC is lower than that of a conventional PCC. Secondly, the optimal L/B of a main-hull of the trimaran PCC in still water is determined. The optimal L/B of the main-hull varies with ship speed and size because the wave resistance decreases but the frictional resistance increases as L/B of the hull increases. As ship size increases, the optimal L/B of the main-hull of the trimaran PCC decreases.     

Influence of local and external processes on the annual nitrogen cycle and primary productivity on Georges Bank: A 3-D biological–physical modeling study

Georges Bank is one of the world's most highly productive marine areas, but the mechanisms of nutrient supply to support such high productivity remain poorly understood. Intrusions of nutrient-poor Labrador Slope Water (LSW) into the Gulf of Maine (NAO-dependent) potentially can reduce nutrient delivery to the bank, but this mechanism has not been quantitatively examined. In this paper, we present the first whole-year continuous model simulation results using a biological–physical model developed for the Gulf of Maine/Georges Bank region. This high-resolution three-dimensional coupled model consists of the Finite Volume Coastal Ocean Model (FVCOM) and a Nitrogen–Phytoplankton–Zooplankton–Detritus (NPZD) model, and was used to examine the influences of local and external processes on nitrogen and phytoplankton dynamics on Georges Bank. The model captured the general pattern of spatial-temporal distributions of nitrogen and phytoplankton and provided a diagnostic analysis of different processes that control nitrogen fluxes on Georges Bank. Specifically, numerical experiments were conducted to examine seasonal variation in nitrogen transport into the central bank (new nitrogen supply) versus nitrogen regenerated internally in this region. Compared with previous observation-based studies, the model provided a quantitative estimate of nitrogen flux by integrating the transport over a longer time period and a complete spatial domain. The results suggest that, during summer months, internal nitrogen regeneration is the major nitrogen source for primary production on the central bank, while nitrogen supply through physical transport (e.g. tidal pumping) contributes about 1/5 of the total nitrogen demand, with an estimated on-bank nitrogen transport at least 50% less than previous estimates. By comparing the model runs using different nitrogen concentrations in deep Slope Water, the potential influence of NAO-dependent intrusions of LSW was examined. The results suggest that the change of nitrogen concentration in the deep Slope Water may not have a significant impact on nitrogen and phytoplankton dynamics on the well-mixed central bank, largely due to limited nutrient exchange across the tidal mixing front and enhanced near-frontal nutrient uptake. However, relatively more significant impact was observed in the model simulations if both well-mixed and seasonally-stratified areas (inside 100 m isobath of the bank) were considered in flux calculations.