Regional differences in the timing of recent air warming during the past four decades in China

Global surface temperature has dramatically increased in the past decades. It is critical to evaluate such a change using appropriate approaches. The previous studies for assessment of the change usually used overall trends of temperature series (i.e. slopes of simple linear regression of temperature versus year based on a least-square analysis) for entire study period. Temperature trends, however, differ among different periods, i.e. there are often breakpoints in the temperature series. Therefore, the overall linear trend of a temperature series may conceal some of the temporal characteristics of the temperature change. To precisely characterize the temporal and spatial patterns of air temperature change in China, we analyze the annual mean temperature series between the year of 1961–2004 for 536 meteorological stations across China, using piecewise linear regression approach. We found remarkable breakpoints in the annual mean temperature during the study period across the country. The annual mean temperature started to increase in 1984 at a rate of 0.058°C/a at the country level. The year when warming started appeared to be gradually later from the north to the south: temperature increased since the 1970s in the north (north of 40°N), and did not rise until the 1980s in most areas of the south (south of 40°N), with warming starting in 1983 in the Tibetan Plateau. The trends in annual mean temperatures showed a large spatial heterogeneity across China: a relatively small rising with a rate of 0.025–0.05°C/a in the Sichuan Basin, Central China and South China; the greatest increase in some parts of northwest China (i.e. Xinjiang) with up to a rate of 0.1°C/a; and rising at a rate of >0.05°C/a for most regions of the country. The feedbacks of cold waves and snow may be responsible for such regional differences in the timing and rates of warming in China.     

普光气田P302-2井焚烧炉试气技术

详细讨论高含硫测试技术及资料解释影响因素的基础上,重点对高含硫气田放喷试气流程、产出气燃烧工艺、测试工艺、试井解释方法进行了深入的研究分析,提出了高含硫气井试气流程采用EE级放喷与HH级测试并联组合流程,焚烧炉燃烧方式以及修正等时测试技术。并在普光气田P302-2井的现场进行了成功应用,获取了可靠的地层测试资料,建立了修正后的产能方程,进一步落实了普光气田的储量基础,对高含硫气田开发具有重要的指导意义。     

曲导线上变径圆的包络线及其应用

本文提出了曲导线上变径圆包络线的概念,并推导出求解包络线的解析算式,给出了计算机实现的具体算法。通过离心泵叶轮轴面流道CAD等实例中的应用,证明该方法可作为基础算法应用到许多相关的领域中。     

无侧向力马达的性能分析及实验研究

本支分析研究了一种全新的柱塞卸荷式径向马达,该马达的主要特点是速度区间宽、结构紧凑、柱塞副消除了侧向力。在结构分析的基础上,对马达的效率特性、起动性能和速度特性进行了探讨,并通过实验证实了上述分析的正确性,为这种马达的设计提供了依据。     

幂乘硬化方程相互关系和强化系数k值的研究

对金属的流变曲线用三个幂乘表达式进行了拟合及理论分析;初步探讨了强化系数 k 值的变化规律.结果表明:Hollomon、Ludwik、Swift 三个公式所描述的流变硬化曲线都存在转折,即都存在“多 n”现象,且对应的各转折应变值基本相等;同时经推导并实验证明三个公式的硬化指数间存在关系式:n=(n′—1)/(1—(1/n″)因此,阶段性是材料特性的反映.对 k 值的研究指出:k 值是一个与强度指标关系密切的参量,主要受控于σB.实验证实,各 k 值与σB 间均呈线性关系.k 值随基体和第二相的变化趋势正好同 n 值相反.可以认为,n 值和 k 值是矛盾的统一,客观地反映了材料本身固有的强韧配合特性.     

探求大Carmichael数的一种方法

如果奇合数m满足:对每一个整数a,(a,m)=1,均有a~(m-1)≡1(mod m),则m称为Carmichael数.本文给出一种探求大Carmichael数的方法,并给出一些超过10~(8300)的Carmichael数.     

粉尘粒子在多段冲击式静电除尘器中的运动与沉降

本文对粉尘粒子在多段冲击式静电除尘器中的沉降机理进行了研究。在分析气流绕收集极流动的基础上,得出了粉尘粒子运动和沉降的规律,并给出了各种条件下多段冲击式静电除尘器收集效率的计算公式。     

凹凸棒石粘土及其在水处理中的应用

介绍了一种价格低廉的新型吸附剂一凹凸棒石粘土.凹凸棒石比表面积大,吸附能力强,化学稳定性好.对水中多种污染物具有很好的去除能力.再生方便,再生效率高.     

延吉市化肥厂有效能分析

本文以工厂生产数据为依据,对全系统物流、能流进行有效能分析.残余热力学性质计算采用简便方法,列出有效能平衡表,绘制出产品有效能能流图.结果表明:有效能效率为32.38%,其中造气部分有效能损失为最大,其次为锅炉部分,再次为变换和合成部分.这四个部分有效能损失占总损失之83.3%.由此,给节能方向与措施提供理论依据,对每工序进行热力学分析打下基础.     

Synthesis and anticonvulsant activity of 7-benzylamino-4,5-dihydro-［1,2,4］triazolo［4,3-a］quinolines

A series of 7-substituted-benzylamino-4,5-dihydro-［1,2,4］triazolo［4,3-a］quinoline derivatives was synthesized and evaluated for their anticonvulsant activity. The subcutaneous pentylenetetrazole test (sc-PTZ) demonstrated that the most effective compound in controlling the sc-PTZ induced seizure was 7-(3-bromine-benzylamino)-4,5-dihydro-［1,2,4］triazolo［4,3-a］quinoline (4j) with an ED₅₀ of 5.0 mg/kg and the PI of 20.7, which was also safer than the reference drugs. And the maximal electroshock test (MES) demonstrated that among these derivatives, 7-(3-fluorobenzylamino) -4,5-dihydro-［1,2,4］trizolo［4,3-a］quinoline (4i), with an ED₅₀ of 15.3 mg/kg and the PI of 7.2, was the safest in MES test. Furthermore, their neurotoxicities were measured by the rotarod neurotoxicity test, and the results showed that all derivatives possessed lower neurotoxicity.