Soil properties and their spatial pattern in an oasis on the lower reaches of the Tarim River, northwest China

In this study, classical, geostatistical methods and a geographical information system have been used to identify soil properties including soil organic carbon (SOC), total nitrogen (total N), salt content (SC) and soil moisture (SM), and their spatial variation as well as their relationships with groundwater, land use, and soil texture. The data came from 36 soil samples from 0 to 20 cm depth, and 36 groundwater samples in the Tikanlik Oasis on the lower reaches of the Tarim River, northwest China. The objective was to provide a scientific basis for understanding the heterogeneity of the spatial distribution of soil properties on a large scale with the goal of accelerating the sustainable development of agriculture in the oasis. The results showed that the SC and SM of the surface soil varied greatly, but the SOC and total N varied very little. A possible reason for the low variability of SOC and total N was the relatively consistent human activities within the typical agricultural oasis with more than 75% land used as cropland and orchards, because there was no significant effect of land use types on soil total N and SOC. Geostatistical analysis and the kriging estimator showed that SC and SM had a strong spatial autocorrelation. One-way ANOVA and LSD suggested that land use was the main structural indicator that resulted in the spatial autocorrelation of SC and SM within the 0-20 cm soil depth through its significant differences in soil texture, irrigation and groundwater. In particular, croplands and orchards had significantly higher SM, silt and clay particle percentages and lower SC compared to other land uses due to regular irrigation. Additionally, irrigation could effectively relieve the degree of the hazard from soil salt and soil water stress in cropland.     

微生物菌肥与化学肥料配施对盈江省藤生长的影响

为了解不同肥料种类及其施肥量对盈江省藤生长的影响,采用L₉(3⁴)正交试验设计对其2年生幼林进行连续3年的微生物菌肥与复合肥和磷肥配施试验。结果表明,3年中不同因素的各水平组合间苗木的地径、株高、叶片数和冠幅均呈现极显著的差异(P<0.01)。施用复合肥和磷肥总体呈现显著(P<0.05)或极显著(P<0.01)地抑制盈江省藤生长的现象。不同肥料配施试验组合的地径、株高和叶片数均大于对照的相应指标。试验期间,单施微生物菌肥0.3~0.6 g/株即可满足盈江省藤生长的需求。     

基于FSEC赛车电池箱的结构设计与强度分析

以中国大学生电动方程式赛车的电池箱体研究为背景,对电池箱的结构设计和强度分析方面进行了研究论证,提出了电池箱设计的总体思路,使电池箱的结构设计紧凑合理,工作安全可靠,符合赛事规则。这对纯电动乘用车在电池箱的结构设计方面也具有参考和借鉴的价值。     

二化螟对杀虫单等4种杀虫剂的抗药性

以安徽太湖县敏感地区二化螟（Chilo suppressalis Wallker)自然种群为敏感种群，根据用药水平差异，有代表性地选用浙江，江苏和安徽3地区田间种群，监测了二化螟对杀虫单等4种杀虫剂的抗性水平，结果表明：（1）浙江慈溪二化螟3幼译杀虫单已产生高水平抗性（RR＝54．6），对杀螟松产生了中等水平抗性（RR＝13．9），对敌敌 氰戊菊酯仍较敏感；（2）安徽安庆二化螟3龄幼虫对杀虫单处于中抗水平（RR＝10．8），对杀螟松，敌短短 畏和氰戊菊酯仍较敏感。（3）江苏兴化二化螟3龄幼虫与安庆相似，对杀虫单中抗（RR＝12．6），对其它被试药剂仍较敏感；（4）不同地区用3龄和6龄幼虫测定的抗药性水平相近，同时用太湖敏感种群和慈溪高抗种群进行的增效试验表明，TPP 对杀虫单无增效作用，但PBO在抗性种群中对杀虫单有 一定的增效作用，说明该种群对杀蝗抗性与多功能氧化酶有一定的关系。     

危难时刻,训练爱犬救你

犬是最忠于人类的动物。在带犬执行任务中，犬主人经常面临突遭袭击或袭击后的危险，针对这一问题，要培养犬良好的应变能力，培养其在突发事件中护主救人的能力，综合发挥犬的特殊作用。     

E1 级防潮型中密度纤维板的工艺因子对甲醛释放量的影响

为了生产符合要求的E1 级防潮型中密度纤维板, 胶粘剂最好使用三聚氰胺改性的低毒脲醛树脂胶粘剂, 三聚氰胺添加量为80 gkg-1时能满足E1 级防潮型中密度纤维板的生产要求。在胶粘剂已定的情况下, 施胶量增加可以降低板材甲醛释放量, 11 %～ 13 %施胶量比较合适;热压温度升高、热压时间延长能明显降低板材中甲醛释放量;随着中密度纤维板厚度增加, 板材中甲醛释放量也能降低。本次实验中板材厚度为16 mm 时, 热压温度190 ℃,热压时间25 smm-1是比较合适的。图4 表1 参7     

Involvement of Sirt1 in mouse myocardial hypertrophy induced by isorenin

AIM: To investigate the expression and function of sirtuin 1 (Sirt1), one of the class III histone deacetylases, in hypertrophied mouse myocardium induced by isorenin (ISO). METHODS: The Kunming mice were randomly divided into 3 groups: control group, ISO group and ISO+nicotinamide (NAM) group. The myocardial hypertrophy was induced by dorsal subcutaneous injection of isorenin. Nicotinamide, an inhibitor against Sirt1, was given by peritoneal injection. Heart weight index (heart weight/body weight), hematoxylin and eosin staining, transmission electron microscope and mRNA expression of brain natriuretic peptide (BNP) were observed to identify the myocardial hypertrophy. The expression of Sirt1 in mRNA and protein levels was detected by RT-PCR and Western blotting, respectively. RESULTS: Compared to control group, the results of heart weight index, hematoxylin and eosin staining, the observation of transmission electron microscopy and mRNA expression of BNP showed that the mouse myocardial hypertrophy was induced by isorenin successfully. The Sirt1 expression was increased in hypertrophy model group (P<0.01 vs control group). Treatment with nicotinamide inhibited the cardiac hypertrophy induced by ISO (P<0.05 vs ISO group) and decreased the expression of Sirt1 (P<0.01 vs ISO group). CONCLUSION: Activation of Sirt1 might be involved in the process of myocardial hypertrophy stimulated by isorenin in mice.     

北兴农场近10年农业气象条件分析

黑龙江省北兴农场是气候较为脆弱的地区,易出现突发性灾害天气或局地、短时的异常天气,对农业生产危害较大。近10年北兴农场先后遭遇了1995年早霜,1997年春末、初夏大涝,1998年晚霜,2002年夏季的低温冷害、寡照,2003年的长期干旱等气象灾害。能否通过气象条件的对比,使我们了解     

水杉基3层结构实木复合地板的制备及其导热声学性能的研究

将水杉木材用于基材制备实木复合地板并与市面常见的多层和3层结构实木复合地板的理化性能、导热及声学性能进行比较。结果表明：水杉基3层结构实木复合地板的含水率为10.7%,甲醛释放量为0.112 mg/m³,浸渍剥离指标符合国家标准要求。3种实木复合地板由于结构和树种组成不同,导热性有较大差异,水杉基3层结构实木复合地板导热系数为0.188 W/(m·K),在3种实木复合地板中最低,保温隔热效果最好。水杉基3层结构实木复合地板在0.2～2 kHz范围内11个频率条件下的吸声系数,均高于相同频率条件下其他2种实木复合地板。密度、含水率、漆膜厚度等均对产品吸声系数有影响。     

Effect of different ions on larval metamorphosis of the mussel Mytilus galloprovincialis

Metamorphic responses of pediveliger larvae of Mytilus galloprovincialis to different ions were investigated through a series of bioassays. Effects of tetraethylammonium chloride (TEA) on inductive effects of these above ions were also investigated. Excess ions including Li⁺, Cs⁺, Rb⁺ and Ca²⁺ induced larval metamorphosis at 10^?3 M to 5 × 10^?2 M in 24‐h exposure assays. In continuous exposure assays, only excess Ca²⁺ showed inductive activity and induced 25% metamorphosis at 5 × 10^?2 M. Larval responses to Li⁺ and Rb⁺were inhibited by TEA, while induction of metamorphosis by Cs⁺and Ca²⁺ was independent of the presence of TEA. Thus, these ions used can be useful inducers of larval metamorphosis for application in the aquaculture industry. The finding provides new insights on the biochemical mechanism controlling larval metamorphosis in this species.