菹草对普通小球藻和铜绿微囊藻的化感作用

选取沉水植物菹草与浮游藻类普通小球藻、铜绿微囊藻为研究对象,在菹草共培养胁迫下测定2种藻单独存在和按1∶1混合情况下的光密度、叶绿素a(Chl-a)、最大光化学量子产量、相对电子传递速率、可溶性糖、丙二醛以及超氧化物歧化酶活性的变化。结果表明,在菹草存在的条件下,普通小球藻、铜绿微囊藻和二者混合藻的生长被快速、强烈地抑制,抑制率最大值分别为74. 38%、80. 98%和89. 63%。3个处理组的光密度值、叶绿素a、可溶性糖和超氧化物歧化酶均低于对照组,且随时间呈明显的下降趋势,说明其光合能力逐渐减弱;而丙二醛含量在0～6 d却高于对照组,表明可能发生了浮游藻类膜脂过氧化过程。     

Preparation of free‐standing chitosan membranes for Chlorella vulgaris harvest and examination on suppression of algae‐fouling properties

Free‐standing chitosan membranes were prepared using genipin as crosslinker, using several molecular weights of polyethylene glycol (PEG) as a void‐forming agent. The membrane surface formation and chitosan polymer chain crosslinking were confirmed through SEM and FTIR, respectively. The water flux was remarkably increased with increasing molecular weight of PEG employed in preparation of composite chitosan membrane (J∝[PEG(MW)]0.85), it appeared over 6000 Da of PEG. During Chlorella vulgaris harvest using chitosan membranes, focus was made on algae‐fouling caused by the deposition of cells and extracellular organic matter, and it was found that membranes employing lower molecular weight of PEG (under 10000 Da) had been maintaining the high flux recovery after alternating filtration cycles, in addition to PEG20000 containing membrane. The chitosan membrane prepared with lower molecular weight of PEG exhibited better suppression of algae‐fouling properties. The Chlorella vulgaris harvesting results indicated that cell rejection rate reached above 98%.     

Treatment of recalcitrant wastewater from ethanol and citric acid production using the microalga Chlorella vulgaris and the macrophyte Lemna minuscula

Laboratory-scale experiments were performed to develop a procedure for biological treatment of recalcitrant anaerobic industrial effluent (from ethanol and citric acid production) using first the microalga Chlorella vulgaris followed by the macrophyte Lemna minuscula. This recalcitrant dark-colored wastewater, containing high levels of organic matter and low pH, prevents the growth of microalgae and macrophytes, and therefore, could not be treated by them. Therefore, the wastewater was diluted to 10% of the original concentration with wash water from the production line. Within 4 days of incubation in the wastewater, C. vulgaris population grew from 5 x 10(5) to 2 x 10(6) cells/mL. This culture reduced ammonium ion (71.6%), phosphorus (28%), and chemical oxygen demand (COD) (61%), and dissolved a floating microbial biofilm after 5 days of incubation. Consequently, L. minuscule was able to grow in the treated wastewater (from 7 to 14 g/bioreactor after 6 days), precipitated the microalgal cells (by shading the culture), and reduced other organic matter and color (up to 52%) after an additional 6 days of incubation. However, L. minuscula did not improve removal of nutrients. This study demonstrates the feasibility of combining microalgae and macrophytes for bioremediation of recalcitrant industrial wastewater.     

石油污染土中微生物的分离鉴定及降解特性

为了为汽油污染土的微生物修复提供优良菌种,以LB培养基为基质,从石油污染土中对汽油降解菌进行了分离鉴定,以降油培养基为基质对分离得到的菌株进行汽油降解率的测定,以培养温度、培养基pH值及培养时间为参数对5种具有优良汽油降解性能的菌株进行单因素试验,基于单因素试验结果进行三因素三水平的正交试验后,以汽油降解率为响应值对试验结果进行响应面分析,筛选出具有优良降解性能的菌株,并确定了菌株降解汽油的最佳条件。结果表明:从石油污染土中分离出了9种具有汽油降解性能的菌株,其中,铜绿假单胞菌、假单胞菌属、苍白杆菌属、博得特氏菌属以及戈登氏菌属具有优良降解性能,这5种菌降解汽油的最优条件为:铜绿假单胞菌、假单胞菌属、苍白杆菌属、博得特氏菌以及戈登氏菌的最佳培养温度均为32℃,培养基pH值均为7.0,培养时间均为20h,降油培养基中的汽油降解率分别为70.12%、76.42%、75.66%、77.50%和73.22%。     

Biosorption of U(VI) by the green algae Chlorella vulgaris in dependence of pH value and cell activity

Biosorption of uranium(VI) by the green alga Chlorella vulgaris was studied at varying uranium concentrations from 5 μM to 1 mM, and in the environmentally relevant pH range of 4.4 to 7.0. Living cells bind in a 0.1 mM uranium solution at pH 4.4 within 5 min 14.3 ± 5.5 mg U/g dry biomass and dead cells 28.3 ± 0.6 mg U/g dry biomass which corresponds to 45% and 90% of total uranium in solution, respectively. During 96 h of incubation with uranium initially living cells died off and with 26.6 ± 2.1 mg U/g dry biomass bound similar amounts of uranium compared to dead cells, binding 27.0 ± 0.7 mg U/g dry biomass. In both cases, these amounts correspond to around 85% of the initially applied uranium. Interestingly, at a lower and more environmentally relevant uranium concentration of 5 μM, living cells firstly bind with 1.3 ± 0.2 mg U/g dry biomass to 1.4 ± 0.1 mg U/g dry biomass almost all uranium within the first 5 min of incubation. But then algal cells again mobilize up to 80% of the bound uranium during ongoing incubation in the time from 48 h to 96 h. The release of metabolism related substances is suggested to cause this mobilization of uranium. As potential leachates for algal-bound uranium oxalate, citrate and ATP were tested and found to be able to mobilize more than 50% of the algal-bound uranium within 24 h. Differences in complexation of uranium by active and inactive algae cells were investigated with a combination of time-resolved laser-induced fluorescence spectroscopy (TRLFS), extended X-ray absorption fine structure (EXAFS) spectroscopy and attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy. Obtained results demonstrated an involvement of carboxylic and organic/inorganic phosphate groups in the uranium complexation with varying contributions dependent on cell status, uranium concentration and pH.     

Isolation, identification and utilization of thermophilic strains in aerobic digestion of sewage sludge

Two representative thermophilic bacterial strains (T1 and T2) were isolated from a one-stage autothermal thermophilic aerobic digestion pilot-scale reactor. 16S rRNA gene analysis indicated that they were Hydrogenophilaceae and Xanthomonodaceae. These isolated strains were inoculated separately and/or jointly in sewage sludge, to investigate their effects on sludge stabilization under thermophilic aerobic digestion condition. Four digestion conditions were tested for 480 h. Digestion without inoculation and inoculation with strain T2, as well as joint- inoculation with strains T1 and T2, achieved 32.6%, 43.0%, and 38.2% volatile solids (VS) removal, respectively. Removal in a digester inoculated with stain T1 only reached 27.2%. For the first 144 h, the three inoculated digesters all experienced higher VS removal than the digester without inoculations. Both specific thermophilic strains and micro-environment significantly affected the VS removal. DGGE profiles revealed that the isolated strains T1 and T2 can successfully establish in the thermophilic digesters. Other viable bacteria (including anaerobic or facultative microbes) also appeared in the digestion system, enhancing the microbial activity.     

新疆某医院门诊楼隔震结构设计与分析

对位于设防烈度为8度(0.3g)区采用隔震技术的某医院门诊楼结构进行了设计与分析,确定结构选用隔震支座的类型,采用SAP2000软件运用振型分解反应谱法和时程分析法对结构进行了地震反应分析。结果表明:所选用的滑板隔震支座和橡胶隔震支座布置位置是合理的,并且采用隔震技术可显著降低上部结构的楼层剪力、层间位移。根据《建筑抗震设计规范》GB50011-2010要求,采用隔震技术后,上部结构地震作用和构造措施可按降一度执行。     

中小城市传统建筑文化景观的保护

每个城市都有自己的传统建筑文化景观特色,建筑景观的整体性与多样性统一形成了城市的特色,结合义乌市的建筑景观特色分析,从布局的半开放性、设计的地域性、装饰的工艺性三个方面探讨了城市传统建筑文化景观的整体性保护,从而使传统文化景观在新建筑、新城市中得到传承。     

聚落文化在建筑设计中的演绎和拓展

本文对影响福州地区传统聚落民居的自然环境因素和社会文化因素进行分析,阐述福州聚落民居演化过程,结合永泰温泉度假村的设计尝试,从文化特质、空间形态、材料技术、景观层面传承地域文化精神,形成整体的地域主义的建筑观。     

Compressive load response of geogrid-reinforced fine,medium and coarse sands

This paper presents data obtained from a series of laboratory plate load tests performed on geogrid-reinforced sand beds. Fine, medium and coarse sands were used as test sand beds. Circular geogrids of diameter 120 mm were used as reinforcement layers. Improvement in load–settlement response was studied. The test sand beds were compacted to a relative density of 50%. A surface footing plate of diameter 60 mm was used as the shallow foundation. It was found that the horizontal geogrid reinforcement improved the load–settlement response. The applied load for a deformation of 0.5 mm in the case of geogrid-reinforced fine sand, medium sand and coarse sand was, respectively, 83 N, 44 N and 87 N, whereas it was 63 N, 38 N and 47 N when the sands were unreinforced. Load–settlement response was found to improve further with increase in number of geogrid layers and with decrease in spacing between them. Load improvement ratio (LIR), defined as the ratio of load for a given settlement in geogrid-reinforced case to that for the same settlement in unreinforced case, increased with number of geogrids (n) for all sands, but the improvement was significant in the case of coarse sand.     

Removal of ammonium and phosphorus ions from synthetic wastewater by the microalgae Chlorella vulgaris coimmobilized in alginate beads with the microalgae growth-promoting bacterium Azospirillum brasilense

Coimmobilization of the freshwater microalga Chlorella vulgaris in alginate beads with the microalgae growth-promoting bacterium Azospirillum brasilense under semi-continuous synthetic wastewater culture conditions significantly increased the removal of ammonium and soluble phosphorus ions compared to immobilization of the microalgae alone. In continuous or batch cultures removal of these ions followed a similar trend but was less efficient than in semi-continuous culture. It is proposed that coimmobilization of a microalgae with microalgae growth-promoting bacteria can serve as a tool in devising novel wastewater treatments.     

Phytoplankton biomass and production in the river meuse (Belgium)

The biomass and production of the phytoplankton in a relatively unpolluted reach of the River Meuse (Belgium) were followed through two years (1983 and 1984). Chlorophyll a varied from 0.2 to about 120 mg m⁻³, and production ranged between 0.05 and 5.78 gC m⁻² d⁻¹. The mean photosynthetic quotient (PQ) was 1.25.

The parameters of the light-photosynthesis relationship (P_opt and l_k) were calculated and related to the variations of temperature and light in the water column. A simple model allowed calculations of the annual production, which was estimated to be 494 gC m⁻² yr⁻¹ in 1983 and 547 gC m⁻² yr⁻¹ in 1984.

Finally, a simple model is developed, which explains the relationship between phytoplankton development and discharge; this model shows how the effect of discharge can be described by a “dilution rate” of the plankton growing in the river water.     

历史文化名城滨水地带的保护和发展与和谐

以江西赣州三江六岸城市设计为例,探讨了历史文化名城滨水地带的保护、发展与和谐,分析了该滨水地带的景观设计理念,归纳了该景观"以水为带,以桥分段,一轴两心"的格局,以积累历史文化名城的保护经验。     

企业文化在企业发展中的作用

分析了文化对政治、经济、社会、生活产生的潜在影响及发挥的重要作用,介绍了企业文化在企业发展中的重要性,提出只有继承和发扬中华民族的优秀传统文化,吸收和借鉴人类先进文化,才能建立起优秀的企业文化,据此才能建立起比较完善的社会主义市场经济体制,实现兴企、富民、强国的目标。     

结构可调式换热器的设计原理及其特性分析

从表面式换热器的结构性能优化和便于调控管理的角度出发,提出了换热器的介质结构和结构系数的概念及其实现方法;在对结构可调式换热器热力特性和控制特性分析的基础上,提出了基本设计方法。认为这种换热器在用于自动控制的通风空调系统和机电一体化上具有一定的优越性。     

漕运文化与中国城市发展

以漕运制度为切入点，分析了漕运文化与都城及商业城镇发展的关系，进而探讨了城市滨河地区及其建筑在漕运文化影响下的兴衰和变迁，对理解我国城市的发展沿革和当前的城市更新具有积极和创新的意义。     

A sequential response surface method and its application in the reliability analysis of aircraft structural systems

The reliability analysis of aircraft structural systems is difficult to evaluate due to the complexity of the g-function g(x), the probability density function ƒ(x) and the dimension m of the problem. In many cases, the g-function can be very complex and the number of evaluation of g(x) may dominate the computation cost. Response Surface Methods may alleviate the problem by giving a simple approximation, g′(x), to the true g-function, which can then be used instead of g(x) for the reliability analysis.In this paper, a new Sequential Response Surface Method together with Monte Carlo Importance Sampling (MCIS) is suggested. Based on the method, a reliability analysis program RSM for aircraft structural systems is developed.Several examples are presented to illustrate the method.     

The effect of bacterial contamination on the heterotrophic cultivation of Chlorella pyrenoidosa in wastewater from the production of soybean products

This study examined the impacts of bacteria on the algal biomass, lipid content and efficiency of wastewater treatment during the heterotrophic cultivation of Chlorella pyrenoidosa. Our results showed that soybean-processing wastewater can enhance the accumulation of lipids in algal cells and thus raise the lipid yield in the pure culture. The bacteria coexisting with algae improved the degradation of total nitrogen (TN), total phosphorus (TP), glucose and chemical oxygen demand (COD). Although the biomass productivity of algae was not significantly affected, the total algal lipid content and lipid production rate were slightly reduced when bacteria coexisted with algae. The difference in the compositions of the medium is presumed to be the main contributing factor for the variation in total lipid content in presence and absence of bacteria. The TN, TP, and COD decreased during the assimilatory process undertaken by C. pyrenoidosa, and the removal efficiency of TN by bacteria depended on the type of nitrogen species in the medium. Additionally, the apparent interaction between the bacterial and algal cultures varied with the changes in experimental conditions. Algae could compete with bacteria for the carbon and energy sources, and inhibit the growth of the bacteria in the presence of high organic matter concentration in the medium.     

2002年我国混凝土机械生产发展情况和产品开发动态

1生产发展情况2002年,由于我国国民经济的快速增长,公路建设、城市建设、电力建设、房地产升温以及国家其他大批基本建设项目的开工,极大地促进了商品混凝土的应用和推广。椐全国30个省市统计,2002年商品混凝土实际产量达1.3914亿m3(见表1),比2001年增长40%。由于商品混凝土的发展,促进了商品混凝土机械的快速发展。商品混凝土机械主要产品有混凝土搅拌楼(站)、混凝土搅拌输送车、拖式混凝土泵、混凝土泵车和散装水泥运输车等设备。椐26家生产企业的不完全统计,2002年生产销售混凝土搅拌站(楼)900台套,比2001年增长66%;生产销售混凝土搅拌运…     

高层建筑的隔震原理与技术

隔震技术目前正逐渐应用于高层建筑。但对于高层建筑,延长结构周期带来的抗震性能改善并不显著,而分析结果表明,隔震技术仍可以显著降低结构的绝对加速度响应。本文以线弹性动力时程分析和反应谱法为基础,从延长结构周期原理与隔震层滤波原理两方面分析了建筑隔震的减震效果。分析结果表明,在现有基于承载力抗震设计框架下,两种原理的分析结果是等效的,而滤波原理能够更加科学的解释隔震技术在降低结构绝对加速度响应方面的减震机理,有助于从基于性能设计更加全面的体现隔震技术的优势。在充分认识隔震原理的基础上,进一步讨论了高层建筑隔震需解决的技术问题,并介绍了日本高层隔震建筑的应用。