土壤水分垂直运移建模与优化

在滴灌条件下,滴头流量对土壤的水分运移影响很大,是影响作物生长的主要因素。依据滴灌条件下土壤水分垂直运移的观测数据,建立滴头流量与水分垂直运移距离的传递函数模型,利用粒子群优化(PSO)算法对模型的各个参数进行辨识与优化。在同一滴头流量下,比较不同土壤水分垂直运移模型的动态变化,验证了土壤水分垂直运移传递函数模型在不同流量下的有效性,为实现作物根系所需水分垂直运移距离的反馈调节,有效地保证作物根系所需的水分,减小水资源浪费创造了条件。     

Earthquakes near Parkfield, California: Comparing the 1934 and 1966 Sequences

Moderate-sized earthquakes (Richter magnitude M(L) 5(1/2)) have occurred four times this century (1901, 1922, 1934, and 1966) on the San Andreas fault near Parkfield in central California. In many respects the June 1966 sequence was a remarkably detailed repetition of the June 1934 sequence, suggesting a recurring recognizable pattern of stress and fault zone behavior.     

Earthquake Swarm Along the San Andreas Fault near Palmdale, Southern California, 1976 to 1977

Between November 1976 and November 1977 a swarm of small earthquakes (local magnitude 相似文献   

Crustal Spreading in Southern California: The Imperial Valley and the Gulf of California formed by the rifting apart of a continental plate

The current excitement among geologists and geophysicists stemming from the "new global tectonics" has led to a widespread, speculative reinterpretation of continental geology. The Gulf of California and its continuation into the Imperial Valley provide an excellent opportunity for studying the border zone between the North American and Pacific plates, and an interface of continental and oceanic tectonics. The Salton trough, the landward extension of the gulf, is a broad structural depression, comparable in size with the deeper marine basins of the southern part of the gulf, but here partially filled with sediments deposited by the Colorado River.     

Occurrence of High Ozone Concentrations in the Air near Metropolitan Washington

Relatively high concentrations of surface ozone and the indication that ozone is the inciting agent in fleck injury to tobacco were reported previously (1). Considerable interest therefore attaches to weather parameters on the high-ozone days which may throw light on the source and on the physicochemical processes affecting the ozone level. A source in the direction of nearby Washington, D.C., and photochemical production of the oxidant are indicated. Days with appropriate wind direction but low peak ozone concentration are discussed in terms of coexisting weather parameters. The weather ensemble found on highozone days is considered in relation to instances of fleck injury for which peak ozone levels were not measured.     

高效垂直流人工湿地对污水的深度处理

深圳市环境科学研究院研发的高效垂直流人工湿地由于具有景观效果好、污染物去除效率高等特点,已被广泛地应用于污水深度处理工程.大量实践结果表明,该系统对SS、CODCr、BOD5、NH3-N、TP具有较高的去除效果,出水水质均达到《地表水环境质量标准》(GB 3838-2002)中的Ⅲ或Ⅳ类水质标准.     

Crustal Structure of Yunnan Province, People's Republic of China, from Seismic Refraction Profiles

Seismic refraction, profiles in Yunnan Province, southwestern China, define the crustal structure in an area of active tectonics on the southern end of the Himalaya-Burma arc. The crustal thickness ranges from 38 to 46 kilometers, and the relatively low mean crustal velocity indicates a crustal composition compatible with normal continental crust and consisting mainly of meta-sedimentary and silicic intrusive rocks, with little mafic or ultramafic component. This composition suggests a crustal evolution involving sedimentary processes on the flank of the Yangtze platform rather than the accretion of oceanic island arcs, as has been proposed. An anomalously low upper-mantle velocity observed on one profile but not on another at right angles to it may indicate active tectonic processes in the mantle or seismic anisotropy.     

高温和干旱胁迫下,植物叶片光合系统变化、气孔运动及其调控研究进展

全球气候变暖导致灾难性天气发生频率增高,高温和干旱同时发生的几率逐年增加,针对高温和干旱给植物带来的影响,本文从植物叶片光合系统、气孔运动、逆境胁迫信号传导和叶片气孔开闭调控4个方面进行详细阐述,从植物生理学和细胞生物学角度,讨论了植物叶片气孔运动规律及应用脱落酸对气孔开闭进行调控的研究进展,为抗旱耐高温型植物新品种选育提供理论基础,为科学、经济、高效调控植物叶片气孔运动,防御短暂和长期性逆境胁迫,保证粮食稳产、高产提供科学依据。     

平均税率、标准税率与收入分布对个人所得税累进性的影响

运用中间累进性指标将个人所得税累进性的变化分解为标准税率的影响及收入分布的影响,对再分配效应变化也做了类似的分解,实证分析了我国2005~2011年个人所得税累进性及再分配效应的变化。结果显示,收入分布改变对于累进性的变化发挥主导作用,平均税率对于再分配效应的变化非常关键。因此,个人所得税的改革首先需要在分析居民收入分布的基础上进行,另外在累进性提高的同时也需十分关注税收规模的变化。     

温度和相对湿度对扶桑绵粉蚧存活率的影响研究

为探寻扶桑绵粉蚧（Phenacoccus solenopsis Tinsley）对高温干旱的适应性,在37,39,41,43,45℃,相对湿度20％,30％,50％,70％,90％的条件下对扶桑绵粉蚧雌成虫进行了处理试验,并对扶桑绵粉蚧存活率及发育情况进行了统计.结果表明,扶桑绵粉蚧存活率随温度升高而降低,37~43℃条件下,扶桑绵粉蚧存活率与处理时间长短无关,在45℃条件下,处理时间越长扶桑绵粉蚧存活率越低;不同空气相对湿度条件下扶桑绵粉蚧存活率差异不显著（P ＞0．05）,但空气相对湿度对扶桑绵粉蚧发育历期存在明显影响,即相对湿度高发育历期短,相对湿度低发育历期长;根据试验结果来看,扶桑绵粉蚧在新疆高温、干旱的环境条件下是可以存活的,并可以在野外完成各虫态的正常生长发育,顺利越夏.     

高速铁路“遮蔽地”农业化利用管理初探

针对高速铁路正线征地范围内土地利用方式的多样性,该文采用实地调查、文献研究等方法,阐述了高速铁路"遮蔽地"的定义,分析了"遮蔽地"合理利用的原则和目标,探讨了"遮蔽地"土地使用权设定及其管理方法,最后提出了"遮蔽地"利用与管理应根据其实际使用情况,做好使用权让渡工作等政策建议。     

Rates of late cenozoic uplift, baldwin hills, los angeles, california

Radiocarbon ages for the marine late Pleistocene stratigraphic units of the Baldwin Hills are 36,200 +/- 2,750 years and 28,450 +/- 2,600 years, respectively, defining the termination of marine deposition in this area of the Los Angeles Basin at less than 28,000 years ago. Faunas of the older sample suggest that water depths were about 100 meters at the time of deposition. Shoaling of waters by deposition resulted in very shallow marine to nonmarine conditions about 28,000 years ago. The average rates of uplift for the past 36,000 years have been between 0.5 and 0.8 meter per 100 years.     

中国长白山植物区系的垂直分布格局

为了探讨长白山植物区系的垂直分化特征及其与周边地区植物区系的联系,通过对以往在该地区采集的标本进行分类学鉴定,统计得出长白山共有维管束植物134科517属1 323种。对这些植物从属、种两级进行统计分析,结果表明:长白山4个植被垂直带的植物区系具有明显的垂直分布格局;在整体上具有温带性质,包含有少量的热带成分,主要体现在阔叶红松林带;随海拔的升高,温带性质逐渐减弱,寒带亚寒带逐渐增强。植物区系的垂直变化反映了长白山低海拔植物区系与热带植物区系的联系,以及高海拔地段与北极成分之间的联系。      

Clay Minerals in Playas of the Mojave Desert,California

A method has been proposed for deriving a characteristic determining flow in porous systems. This characteristic combines both area and path-length factors used by earlier authors. For a gas, diffusive flow is proportional to the 4/3 power of the gas-filled porosity, and this function has been derived from consideration of the planar distribution of spherical pores and the interaction of two adjacent planes.     

沿巢湖流域坡岗地地区水稻高效施肥技术研究

[目的]研究建立沿巢湖流域坡岗地地区水稻高效施肥技术。[方法]试验共设5个施肥处理：空白无肥处理（CK）;农民习惯施肥处理;平衡施肥-1处理;平衡施肥-2处理;平衡施肥-1＋油莱秸秆（3000kg／hm^2）处理。其中,CK为不施肥;农民习惯施肥处理的氮磷钾施肥量为N：P2O5：K2O=180kg／hm。：75kg／hm^2：0,全部肥料作基肥,不追肥;平衡施肥-1处理氮磷钾肥用量为N：P2O5：K2O=180kg／hm^2：60kg／hm^2：90kg／hm^2,氮肥按基肥：分蘖肥：穗肥为50％：30％：20％分3次施用;平衡施肥-2处理氮磷钾施肥量同平衡施肥-1,但氮肥按基肥：分蘖肥：穗肥为40％：30％：30％分3次施用;油菜秸秆（有机肥）作基肥,所有施肥处理磷、钾肥全部作基肥施用。[结果]总体上,不同施肥处理均可以提高水稻生物积累量,增加有效穗数和每穗实粒数,从而提高水稻产量。[结论]氮、磷、钾肥配比不合理,氮肥运筹方法不当,仍是目前沿巢湖流域坡岗地地区水稻产量和氮肥利用效率较低的主要原因,在氮肥的施用上,增加分蘖肥和穗肥的比例,同时增加钾肥的施用量,能够使水稻营养生长和生殖生长均衡发展,增加每穗实粒数、千粒重,从而提高水稻产量和氮素回收率,减轻氮肥流失引起的面源污染。     

2个甘蓝F1小孢子培养中高出胚率的诱导技术研究

以2个优良的F1甘蓝为试材,探讨了高温热激、蔗糖浓度、添加和更换培养液培养、激素种类与浓度配比等因素对提高甘蓝小孢子诱导胚产量的影响.结果表明,2个F1甘蓝材料经24 h 、33℃高温热激处理对小孢子胚胎发生是必要的;小孢子在13%蔗糖浓度培养基(NLN-13)中培养胚产量最高,为1.89胚/蕾;高浓度蔗糖的培养基(NLN-17)培养3 d后添加低浓度蔗糖培养基(NLN-10)培养能大幅度提高胚产量,比一直在13%蔗糖的培养基(NLN-13)培养的胚状体增加255.2%;NLN-13培养基中添加0.1 mg/L 6-BA和0.05 mg/L NAA能够诱导出高胚产量.     

不同填料在高负荷垂直流人工湿地系统中净化能力的研究

选取砾石、沸石、无烟煤、页岩、蛭石、陶瓷滤料、高炉钢渣、圆陶粒8种填料,在较高水力负荷（1000～2500mm·d^-1）的条件下,进行垂直流人工湿地模拟柱净化污水实验。结果表明,无烟煤、圆陶粒、砾石具有较好去除有机物的能力,对COD的去除率达到50%以上;钢渣和无烟煤对BOD的去除率达到70%以上。沸石和陶瓷滤料对总氮和氨氮的去除率达到70%以上,其他几种填料对总氮和氨氮的去除率仅为20%左右。高炉钢渣和无烟煤具有较好去除磷的能力,高炉钢渣对总磷和总溶解性磷的去除率达到90%以上,无烟煤对总磷和总溶解性磷的去除率达到60%～70%。孔隙率的变化对垂直流人工湿地的净化能力有显著影响。在垂直流人工湿地处理系统中,通过选择合适的填料,如无烟煤、圆陶粒、沸石,在较高的水力负荷条件下可获得较好的处理效果。