温度两阶段控制策略发酵生产重组角质酶

为进一步提高重组Bacillus subtilis WSHB06-07发酵生产角质酶的产量和生产强度,在pH两阶段控制策略的基础上,考察了温度(27～40℃)对菌体生长和产酶的影响.研究发现,37℃适于菌体生长而30℃适于菌体产酶.通过分析发酵过程中菌体比生长速率及产物比合成速率的变化,确定了温度两阶段控制策略,即0～4 h时控制温度37℃,4 h后将温度调至30℃.通过采用这一优化策略,角质酶酶活和生产强度分别可达312.5 U/mL和13.02 kU L-1 h-1,相比恒定温度37℃控制模式下分别提高了83.4%和10.9%.图6表2参13     

青藏高原东部牧区大—暴雪过程雪灾灾情实时预评估方法的研究

利用青藏高原东部牧区26个县气象站30a的大－暴雪过程资料,以雪灾形成的主导因子－持续积雪日数作为灾情评估的等级标准,应用逐步回归方法,建立了冬半年持续积雪日数对大－暴雪过程的累积降水量、平均气温、最大积雪深度和最低气温降温4个因子的回归方程。经F检验,所有方程的回归效果达到十分显著成显著的水平,从而建立了大－暴雪过程雪灾灾情的灾时预评估方法。通过对1996－1999年资料的对比试用,表明这种预评估方法具有较高的精度和业务化的潜力,可作为雪灾情报服务的一种手段。     

Dispersal, pair formation and social structure in gibbons (Hylobates lar)

We report observations on reproduction, natal dispersal, pair formation, and group structure based on longitudinal observations of several white-handed gibbon (Hylobates lar) groups spanning 18 years. Our observations are at odds with the traditional view that gibbons live in nuclear family groups consisting of a pair of adults and their offspring, and that parents exclude young from the family territory when they reach adult size. In the relatively dense Khao Yai study population, dispersing young usually obtain mates by replacing adults in existing territories, which creates non-nuclear families. Six subadults, five males and one female, matured and dispersed at an average age of 10 years, or about 2 years after reaching adult size. Average natal dispersal distance was 710 m, or between one and two territories away. At least two dispersing males replaced adults in neighboring groups. In one case, forcible displacement of the resident male resulted in a group which included a young juvenile presumably fathered by the previous male, two younger juveniles (probably brothers) from the new male's original group, and (later) offspring of the new pair. Social relations within this heterogeneous group remained harmonious: the adults groomed all the young and play occurred between all preadult members. In only two out of a total of seven cases of dispersal seen did two subadults pair and disperse into new territorial space. Nonreproducing subadults which delay dispersal may be tolerated by the adults provided that they contribute benefits to the adults or their offspring. Possible benefits include behaviors such as grooming, social play with juveniles, and support of the adult male in defending the territory. Delayed dispersal is probably advantageous in a saturated environment where there is no room for floaters, but subadults may also gain indirect fitness benefits by aiding siblings and other relatives. Received: 24 January 1997 / Accepted after revision: 12 January 1998     

中国城市群形成发育的政策保障机制与对策建议

中国城市群是我国未来经济发展格局中最具活力和潜力的核心地区,是我国主体功能区划中的重点开发区和优化开发区,也是未来中国城市发展的重要方向,在全国生产力布局格局中起着战略支撑点、增长极点和核心节点的作用.本文针对中国城市群形成发育中呈现出的新特点和存在的新问题,从权力、财力、法力和能力四方面构建了城市群可持续发展的组织协调保障机制、公共财政保障机制、法律法规保障机制和资源环境保障机制等四大保障机制,提出了加快城市群健康发展的若干对策措施.包括:明确国家归口管理机关,组建国家级城市群协调发展管理委员会和跨城市的行业协调组织;建立城市群公共财政机制和公共财政储备制度;推进城市群一体化发展的立法工作,制定城市群合作公约,修订《城乡规划法》,增补城市群规划的内容;出台《城市群规划编制审批办法》、《城市群规划实施管理条例》和城市群规划技术导则,建立城市群规划执业制度,引导城市群科学规划,加强城市群资源环境保障能力和可持续发展能力建设;依托快速国土轴,加快建设国家高速公路的7918网、国家高速铁路网和空中快线系统,完善城市群快速交通系统;规范统计标准数据,编制并出版中国城市群统计年鉴.     

絮凝剂产生菌B-7的培养条件优化及生长动力学研究

从成都市土壤中筛选分离了1株具有稳定高效的微生物絮凝剂产生菌B-7。考察了碳源、氮源、温度、培养时间、pH等多种因素对絮凝剂（MBF-7）絮凝效果的影响。实验结果表明,该菌株产絮凝剂的最佳培养条件为：碳源为淀粉,氮源为硫酸铵,培养时间为72 h,初始pH为7.0,温度为30℃,对0.4%高岭土悬浊液的絮凝率达到91.3...     

Performance evaluation of the UV/H2O2 process on selected nitrogenous organic compounds: reductions of organic contents vs. corresponding C-, N-DBPs formations

The presence of various organic contaminants in water sources is of concern due to their direct threats to human health and potential to react with disinfectants to form carcinogenic byproducts including trihalomethanes, haloacetic acids and nitrosamines in finished water. This study applied both medium-pressure and low-pressure ultraviolet light coupled with hydrogen peroxide (UV/H₂O₂) to evaluate its efficacy for degradation of selected nitrogenous organic compounds and corresponding disinfection byproduct (DBP) formation. Six organic compounds were chosen as target precursors based on their nitrogen contents and molecular structures. The results showed that higher oxidation capacity resulted in better reduction of organic matters and DBP formation potentials (DBPFPs). However, insufficient contact time and oxidant doses could lead to a rise of DBPFPs in the early stages of UV/H₂O₂ reactions. A greater percentage removal was achieved for organic carbon than organic nitrogen after UV/H₂O₂ treatment, especially for compounds with complicated structure such as diltiazem. During the UV/H₂O₂ treatment, the intermediate products include tertiary amine, dimethyl amine (DMA) or DMA-like structures, which are N-nitrosodimethylamine (NDMA) precursors after chlorination or chloramination. Furthermore, it was observed that using dissolved organic nitrogen and DMA to predict NDMAFP could lead to biased conclusions because of the complex nature of nitrogenous matters in aqueous environments.     

短程反硝化菌种的筛选及条件选择的研究

经对某实验室保存的反硝化混合菌液进行分离复壮,筛选到7株反硝化速率较高的菌株(编号为B06,B08,B15,B16,B19,B21).经正交试验,选出短程反硝化的最佳作用条件.分离株B08在温度25～30℃,pH值7.0～8.0,NO-2N质量浓度200 mg/L,C/N 1.4和厌氧条件下,反硝化8 h,NO-2N的去除率达到86.37%.     

新型取向硅钢低温含氢气氛退火技术安全性分析

随着现代工业对材料要求的提高,为提高硅钢质量和节约能源,新型取向硅钢要求在新工艺下生产,分析新型取向硅钢在新工艺条件下的安全性.     

The dimensions of land use change in rural landscapes: lessons learnt from the GB Countryside Surveys

Rural landscapes are highly dynamic and their change impacts on a number of ecological processes such as the dynamics of biodiversity. Although a substantial amount of research has focused on quantifying these changes and their impact on biodiversity, most studies have focused on single dimensions of land use change. This lack of integration in land use change studies can be explained by the fact that data on the spatial, temporal, and ecological dimensions of land use are seldom available for the same geographical location. In this paper, the benefits of taking into account these three dimensions are illustrated with results derived from the Great Britain Countryside Surveys (CS), a large-scale monitoring programme designed to assess change in the extent and ecological condition of British habitats. The overview of CS results presented in this paper shows that (1) changes in land use composition will translate into a variety of spatial patterns; (2) the temporal stability of land use is often lower than can be expected; and (3) there can be large-scale shifts in the ecological condition of the land use types that form our rural landscapes. The benefits of integrated rural landscape studies are discussed in the context of other national monitoring programmes.