Influence study of constructed rapid infiltration system constructedby purple soil on sewage Nitrogen removal performance

The nitrogen removal performance of a constructed rapid infiltration system (CRI) constructed using the common purple soil and sand from the Three Gorges Reservoir Region in the P.R. China was studied. In order to optimize the construction and the nitrogen removal performance of the CRI, three 1.5 m high columns were examined using mixed media with soil/sand ratios of 2∶1, 3∶1 and 4∶1, respectively. Four soil columns with heights of 0.3, 0.6, 1.0,1.5 meters subsequently were tested using media ratio of 3∶1. It is shown that the CRI constructed by the medium of sand/soil ratio being 4∶1 possesses better removal performance for the removal of NH3 N, NO3 N and TN. The removal rates for NH3 N and TN are 71.7% and 48.8% respectively, close to the nitrogen removal performance of unmixed purple soil. Hence the 4∶1 medium of sand/soil ratio is appropriate. It is also shown that, when considering the functional area of CRI treating the sewage, the upper 0.6 m of CRI is the main area that removes COD and NH3 N, whilst 0.6 m~1.0 m is the main area that removes TN. Increasing the soil layer thickness does not ensure better nitrogen removal performance. The 1.0 m soil layer thickness of a CRI system is appropriate for treating sewage in the Three Gorges Reservoir Region.     

Design of a control system for auto loading and unloading of compressed natural gas bottles

The concept of centralized filling and separate bottle displacement was introduced to reduce the inconvenience of filling compressed natural gas(CNG) vehicles. By taking a programmable logic controller (PLC) as the smart control unit and stepper motors as drive units, a mobile three dimensional table was designed as a working platform. The stepper motor control algorithm was studied, and the system model for the CNG vehicles automatic loading and unloading was constructed. A new automatic loading and unloading system for CNG vehicle bottles was developed. Theoretical analysis and experimental results show that the system can complete the automatic loading and unloading task in 1 or 2 minutes, thereby improving CNG vehicle filling efficiency.     

聚乙二醇胁迫下甘蔗根系蛋白质差异表达图谱分析

以甘蔗品种ROC22为材料,采用含100 g/L聚乙二醇（PEG）6000的Hoagland营养液模拟干旱胁迫处理,SDS-PAGE电泳技术分析干旱胁迫对甘蔗幼苗根系蛋白质的影响。结果表明:与对照相比,24 h胁迫过程中稳定存在的新增蛋白条带为44.5 ku,可能是应答干旱胁迫的主要新增调节蛋白;57.1和29.0 ku 蛋白条带在24 h处理期间相对表达量变化活跃,胁迫初期57.1 ku蛋白条带显著增加,29.0 ku蛋白条带显著下降,胁迫过程中出现起伏变化;而62.7、40.4与48.2 ku蛋白条带在PEG胁迫早期相当长时间保持稳定,后期才出现显著增加与下降; PEG胁迫14 h处理蛋白质条带变化最活跃,新增蛋白分子质量为44.5 ku;消失蛋白分子质量为25.5、18.9 ku;而分子质量为81.8、48.2、38.0、29.0 ku的蛋白条带表达量下降。甘蔗根系蛋白质在响应PEG胁迫的基因表达调控中扮演重要角色,其变化可能与甘蔗PEG胁迫密切相关。     

Frost resistance and chloride ion diffusion of silica fume concrete in a marine environment

The properties of silica fume concrete in natural sea water are studied, with special focus on the relationship between the freeze thaw durability and chloride ion diffusion coefficients. The influence of various factors on concrete resistance to frost and chloride diffusion is studied, including the water cement ratio, equivalent silica fume dosage substitution for cement, and the amount of air entraining agent and compared with that of ordinary concrete. The results show that adding silica fume cannot improve the frost resistance of concrete but it increases resistance to chloride diffusion. Both the frost resistance and chloride diffusion properties can be improved simultaneously when silica fume is used with an air entraining agent. A silica fume content of approximately 10% is the optimum value for the composite resistance to frost and chloride diffusion. A new assessment method (R value method) is proposed to evaluate the composite properties of frost resistance and chloride diffusion of marine concrete.     

基于制造偏差的滴灌系统综合流量偏差率

在文献[10]提出的流量偏差率公式基础上,作了进一步推导,简化了公式中的参数。根据步进法水力解析原理,模拟了不同制造偏差下给定灌水小区的综合流量偏差率,通过对综合流量偏差率的统计分析,验证了理论公式。利用公式分析了制造偏差对综合流量偏差率的影响,提出了灌水小区综合流量偏差率允许值的建议。     

Subjective preference evaluation and analysisof motorcycle sound quality

Noise samples of motorcycles at different engine speeds taken at the position of the ear of a motorcycle operator are selected as the evaluation stimuli to investigate sound preferences of motorcycle sound quality. Subjective testing is carried out via the paired comparison method. Precise calculation of the misjudging rate is adopted to ensure test result reliability. Formulae between subjective preference scores and psychoacoustic parameters are obtained through linear correlation and multi dimensional regression analysis. The results indicate that loudness and roughness are two predominant metrics influencing preference evaluation for motorcycle noise, and the nonlinear equation better describes the dependence of subjective preference scores on psychoacoustic parameters than the linear one.     

Model test and numerical simulation of tailing dam safety forecasting

To explore the safety of dam in future operation, we study the stability of Xiaodae tailing dam, Sichuan Province, P. R. China, via model testing and numerical simulation according to preliminary dam design information. The results show that the deposited beach length initially is shorter and the depth of the saturation line in a tailing dam is relative shallow. The length of deposited beach is relatively long in the middle and later periods, and the saturation line maintains a relatively stable position. The numerical simulation shows that horizontal dam displacement is 0.68 m and the greatest vertical displacement is 3.44 m at the dam vertices when the dam reaches the designed elevation. Meanwhile, the dam possesses normal stability. The largest shear stress in flooding exceeds that of normal conditions and the dam saturation line is higher. Unless measures are taken, these conditions will influence dam security.     

抚育对北京低山侧柏游憩林灌草生物多样性的影响

该文研究低山厚土阳、阴坡侧柏游憩林抚育前和抚育1年后林下灌草生物多样性的变化情况。抚育措施包括清死枝、修活枝、割灌木等。结果表明:在阳坡侧柏游憩林内,抚育后灌木的Shannon指数、Shannon均匀度指数、Simpson指数、丰富度指数升高,提高幅度在0.6%～204.2%之间,且灌木优势种的优势地位减弱;而草本层的Shannon指数、Shannon均匀度指数、Simpson指数、丰富度指数都有所降低,降低幅度在9.0%～19.7%之间,且草本层中优势种的优势地位有所加强。在阴坡侧柏游憩林内,抚育后林下灌木的丰富度指数、Shannon指数和Simpson指数分别提高83.3%、32.4%和13.9%,且灌木优势种的优势地位减弱;而草本层的丰富度指数和Shannon指数增加18.7%和2.5%,且草本优势种的优势地位有所加强。研究认为,在北京低山侧柏游憩林内进行抚育是可行的。      

高枝假木贼种子低温萌发与抗氧化酶系统的关系

高枝假木贼具有胎生萌发特性,并且发生在早春。为揭示该植物在早春低温环境中胎生萌发特性,在实验控制条件下,对种子吸胀萌发过程中3种保护酶活性和丙二醛（MDA）含量进行测定,并与野外自然条件下,不同发育阶段幼苗的保护酶活性变化进行对比分析。结果显示：高枝假木贼种子吸水快,在室内5 ℃低温控制下6 h吸水量趋于平稳。种子在低温吸胀过程中,MDA的含量较高（0.02~0.04 μmol•g^-1）,过氧化物酶（POD）活性保持在高水平稳定状态,过氧化氢酶（CAT）和超氧化物歧化酶（SOD）活性在吸胀4 h之后快速上升。随着种子萌发,不同幼苗阶段MDA含量急剧下降, 维持在0.004 μmol•g^-1的极低水平,POD活性显著下降,SOD活性先下降后上升至幼苗3 cm时达到最高,CAT活性呈缓慢上升趋势。在野外低温条件下,SOD、CAT和POD活性均显著高于5 ℃恒温控制下的幼苗酶活性水平。表明高枝假木贼快速吸胀萌发特性和3种保护酶在吸胀萌发不同阶段的协同作用,共同为胎生萌发在早春低温的正常生长提供保护。     

苏太猪ESR基因多态性及其与繁殖性能的关联分析

本研究采用PCR-RFLP方法对苏太猪的ESR基因PvuⅡ位点多态性进行检测,并分析其与繁殖性能间的关系。结果表明,ESR基因的3种基因型AA、AB、BB在苏太猪中的频率分别为0.089、0.570、0.341;其中在初产母猪中,AA基因型个体的产活仔数（NBA）和初生窝重（BLW）显著高于AB、BB 基因型的个体（P<0.05）;在经产母猪中,AA基因型个体的总产仔数（TNB）及断奶成活数（NW）显著高于AB和BB基因型的个体（P<0.05）,AA和AB 基因型与BB 基因型之间的断奶窝重（WWL）差异显著（P<0.05）;总体上苏太猪ESR基因PvuⅡ 3种基因型个体的繁殖性状存在AA>AB>BB的趋势。