气孔运动机理研究进展

本综述讨论了Ｋ＋在气孔运动中的作用、有机代谢物对气孔运动的影响、渗透调节物质的转动机理、内源和外源信号对气孔运动的影响等方面的研究进展，并结合作者的工作，首次提出微管、微丝在气孔运动中可能具有重要调控作用的设想．     

长期不同施肥对水稻土交换性钙、镁和有效硫、硅含量的影响

为探明合理施肥和土壤培肥的理论依据,研究了4种长期定位施肥(CK、NPK、OM30、OM60)对湖南主要水稻土交换性钙、交换性镁、有效硫、有效硅含量的影响.结果表明,长期不同施肥改变了供试水稻土中上述养分的含量.在含钙较低的黄泥田、河沙泥、红黄泥中,施肥使土壤交换性钙含量显著升高,在相同土壤中其含量高低依序为OM30,OM60,NPK;在含钙较多的青灰泥、白鳝泥、紫潮泥中,施肥使土壤交换性钙含量降低.降低幅度与施入的有机肥量呈负相关.在黄泥田、河沙泥、青灰泥、白鳝泥、紫潮泥中,施肥使交换性镁含量降低,而在红黄泥中施肥则使交换性镁含量升高.N-PK处理使含硫较高的黄泥田、青灰泥、白鳝泥、紫潮泥有效硫含量升高,使含硫较低的红黄泥有效硫含量降低;有机、无机肥配施处理(OM30、OM60)使所有试验水稻土有效硫含量升高.施用钙镁磷肥和有机肥能够提高土壤有效硅含量.     

钾离子在土壤中吸附和解吸动力学研究进展

就国内外有关钾离子在土壤中的吸附、解吸动力学的研究进行了简要的综述。主要论述的内容包括土壤钾离子吸附、解吸动力学常用数学模型。土壤吸附、解吸钾离子的机理，以及影响土壤对钾离子吸附、解吸的因素。最后提出了有待进一步研究的问题。     

CrO42-对两种可变电荷土壤吸附钾的影响

用一次平衡法研究了CrO4^2-对两种可变电荷土壤吸附钾的影响，用火焰光度法测定平衡溶液中的钾，根据差减法计算土壤对钾的吸附量。结果表明，加入铬酸根能增加土壤对钾的吸附量。铬酸根对钾吸附的影响程度与土壤游离氧化铁含量和土壤对铬酸根的吸附量的大小有关。砖红壤游离氧化铁含量高于红壤，它对铬酸根的吸附量也大于红壤，因此，铬酸根对砖红壤吸附钾的影响程度大于红壤。CrO4^2-主要通过自身的吸附增加土壤的表面净负电荷，并从而增加土壤对钾的吸附量。     

基于贝叶斯网的网箱养殖区网箱移动预测建模

由专家知识和给定数据,采用著名贝叶斯网络学习K2算法构造了一个海底网箱养殖水环境指标与网箱移动间的贝叶斯网结构模型.该模型能有效的表达网箱养殖环境各个指标之间以及与网箱移动之间的因果关系和影响程度,实验结果表明,试验数据显示准确性为90.6%,以上证明该方法是有效可行的,表明贝叶斯网络是一种很有前途的网箱移动预测评价方法.     

不同生物炭对酸性农田土壤性质和作物产量的动态影响

为研究不同原料生物炭对农田土壤酸度、交换性能、磷素养分以及作物产量的综合动态影响,试验设置空白(CK)、水稻秸秆生物炭(RSB)、玉米秸秆生物炭(MSB)、小麦秸秆生物炭(WSB)、稻壳生物炭(RHB)和竹炭(BCB)这6种处理,生物炭按质量分数0.1%施入农田进行长期定点试验,测定水稻、油菜和玉米这3季作物产量和作物收割后的土壤理化性质.结果表明,添加不同原料生物炭可有效提高土壤pH和交换性能,降低交换性酸含量,作用效果随时间下降.生物炭对盐基离子组成的影响为提高交换性K⁺、Ca²⁺和Mg²⁺含量,降低Na⁺含量.生物炭能不同程度地增加土壤有机质(SOM)、速效磷、总磷和无机磷(Al-P和Fe-P)含量,作物产量较当季对照显著提高(P<0.05),稻壳生物炭在改良酸性土壤理化性质和提高作物产量方面效果较好.     

Radiological monitoring: terrestrial natural radionuclides in Kinta District,Perak, Malaysia

Natural background gamma radiation and radioactivity concentrations were investigated from 2003 to 2005 in Kinta District, Perak, Malaysia. Sample locations were distant from any ‘amang’ processing plants. The external gamma dose rates ranged from 39 to 1039 nGy h⁻¹. The mean external gamma dose rate was 222 ± 191 nGy h⁻¹. Small areas of relatively enhanced activity were located having external gamma dose rates of up to 1039 ± 104 nGy h⁻¹. The activity concentrations of ²³⁸U, ²³²Th and ⁴⁰K were analyzed by using a high-resolution co-axial HPGe detector system. The activity concentration ranges were 12–426 Bq kg⁻¹ for ²³⁸U, 19–1377 Bq kg⁻¹ for ²³²Th and <19–2204 Bq kg⁻¹ for ⁴⁰ K. Based on the radioactivity levels determined, the gamma-absorbed dose rates in air at 1 m above the ground were calculated. The calculated dose rates and measured dose rates had a good correlation coefficient, R of 0.94. To evaluate the radiological hazard of the natural radioactivity, the radium equivalent activity, the gamma-absorbed dose rate and the mean population weighted dose rate were calculated. An isodose map for the Kinta District was also produced.     

Distribution and ratios of Cs and K in control and K-treated coconut trees at Bikini Island where nuclear test fallout occurred: effects and implications

Coconut trees growing on atolls of the Bikini Islands are on the margin of K deficiency because the concentration of exchangeable K in coral soil is very low, ranging from only 20 to 80 mg kg⁻¹. When provided with additional K, coconut trees absorb large quantities of K and this uptake of K significantly alters the patterns of distribution of ¹³⁷Cs within the plant. Following a single K fertilization event, mean total K in trunks of K-treated trees is 5.6 times greater than in trunks of control trees. In contrast, ¹³⁷Cs concentration in trunks of K-treated and control trees is statistically the same while ¹³⁷Cs is significantly lower in edible fruits of K-treated trees. Within one year after fertilization (one rainy season), K concentration in soil is back to naturally low concentrations. However, the tissue concentrations of K in treated trees stays very high internally in the trees for years while ¹³⁷Cs concentration in treated trees remains very low in all tree compartments except for the trunk. Potassium fertilization did not change soil Cs availability.     

Suitable gamma energy for gamma-spectrometric determination of U in surface soil samples of a high rainfall area in India

The paper presents a systematic study on suitability of various gamma lines for monitoring of ²³⁸U activity in soil samples around a uranium mineralized zone of Kylleng Pyndengsohiong Mawthabah (Domiasiat), Meghalaya in India. The area lies in a plateau region which recieves the highest average annual rainfall (12,000 mm) in the world. The geochemical behaviour of the uranium and its daughter products at such wet climatic conditions imposes restrictions to assess ²³⁸U through gamma lines of radon decay products. Soil samples were collected from nine locations around the uranium mineralization zone for analysis. The ratio of the concentration of uranium obtained from gamma energies of radium daughter products to the 63.29 keV of ²³⁴Th was found to vary from 1.01 to 2.07, which indicates a pronounced disequilibrium between uranium and radium daughters. The results obtained from various gamma energies were validated from the data generated by Instrumental Neutron Activation Analysis (INAA) technique. The ²³⁸U activities from the two analytical methods show a well fitted regression line with correlation coefficient 0.99 which validates the reliability of 63.29 keV energy for estimation of uranium in such conditions.     

页岩气压裂返排液高效破胶剂的研究

针对页岩气开采过程中产生的非常规压裂返排液具有高粘度、高COD及高稳定性的特点,以Fe(NO3)3和Ca(Cl O)2为原料,采用化学湿法中的两步法合成了一种绿色氧化剂K2Fe O4,并对合成出的K2Fe O4进行了定量分析,得到合成的高铁酸钾产率为67.63%,纯度为93.41%。采用X衍射、红外光谱、扫描电镜及X衍射能谱,对合成的K2Fe O4进行了表征。将K2Fe O4作为某气田页岩气压裂返排液的高效破胶剂,并对影响破胶效果的因素进行了分析。确定了K2Fe O4的加量为3 000 mg/L,体系p H为11.0及反应时间为40 min的最优条件,在最优条件下,得到出水的粘度为1.4 m Pa·s,其COD、SS和色度的去除率分别为59.1%、93.3%和88.9%。通过红外光谱和扫描电镜进行了微观观察,对K2Fe O4氧化非常规压裂返排液中主要成分胍胶的过程进行了机理分析。研究还发现,K2Fe O4在还原分解后,具有比单一铁离子更强的混凝效果。因此,K2Fe O4的应用对页岩气压裂返排液的处理有深远的影响。