直喷式柴油机燃用F-T柴油时燃烧特性的研究

根据实测的喷油器针阀升程和示功图，对一台单缸、直喷式柴油机燃用Fischer—Tropsch（F—T）柴油时的燃烧放热规律进行了计算，并系统分析了其燃烧特性．研究结果表明：与0号柴油相比，F—T柴油的喷油延迟角和喷油持续期稍长，滞燃期平均缩短了18．7％，预混燃烧放热峰值平均降低了26．8％，扩散燃烧放热峰值较高，快速燃烧期较短，燃烧持续期相当；燃用F—T柴油时的最高燃烧压力略低，最大压力升高率显著降低，燃烧噪声和机械损失较小，有效燃油消耗率和有效热效率得到了改善．     

Marinamide, a novel alkaloid and its methyl ester produced by the application of mixed fermentation technique to two mangrove endophytic fungi from the South China Sea

For a long time, terrestrial microorganisms are abundant natural pharmaceutical resource for human, but it becomes more and more difficult to find new species and microorganisms with special functions from land as the research goes on. Consequently, the s…     

The DNA sequence and comparative analysis of human chromosome 5

Chromosome 5 is one of the largest human chromosomes and contains numerous intrachromosomal duplications, yet it has one of the lowest gene densities. This is partially explained by numerous gene-poor regions that display a remarkable degree of noncoding conservation with non-mammalian vertebrates, suggesting that they are functionally constrained. In total, we compiled 177.7 million base pairs of highly accurate finished sequence containing 923 manually curated protein-coding genes including the protocadherin and interleukin gene families. We also completely sequenced versions of the large chromosome-5-specific internal duplications. These duplications are very recent evolutionary events and probably have a mechanistic role in human physiological variation, as deletions in these regions are the cause of debilitating disorders including spinal muscular atrophy.     

Susceptibility to leprosy is associated with PARK2 and PACRG

Leprosy is caused by Mycobacterium leprae and affects about 700,000 individuals each year. It has long been thought that leprosy has a strong genetic component, and recently we mapped a leprosy susceptibility locus to chromosome 6 region q25-q26 (ref. 3). Here we investigate this region further by using a systematic association scan of the chromosomal interval most likely to harbour this leprosy susceptibility locus. In 197 Vietnamese families we found a significant association between leprosy and 17 markers located in a block of approx. 80 kilobases overlapping the 5' regulatory region shared by the Parkinson's disease gene PARK2 and the co-regulated gene PACRG. Possession of as few as two of the 17 risk alleles was highly predictive of leprosy. This was confirmed in a sample of 975 unrelated leprosy cases and controls from Brazil in whom the same alleles were strongly associated with leprosy. Variants in the regulatory region shared by PARK2 and PACRG therefore act as common risk factors for leprosy.     

Theoretical study of spin-orbit coupling and zero-field splitting in the spin-forbidden two-state reaction between cobaltacyclopentadiene and isocyanate

The two-state reaction mechanism of CpCo(C_4H_4)with isocyanate on the triplet and singlet potential energy surfaces has been investigated at the B3LYP level.A study is described for the computation of spin-orbit coupling of triplet state of the minimal energy crossing point(CP)with their singlet states and of the zerofield splitting(ZFS)parameters of the triplet states,including the full one-and two-electron terms of the BreitPauli Hamiltonian.There are two key crossing points along this two-state reaction pathway.The first crossing point—CP2 exists near~1B.The reacting system will change its spin multiplicity from the triplet state to the singlet state near this crossing region.Although the spin-orbit coupling interaction and ZFS D-tensor of the CP2 region are very strong,the reaction system will occur the reverse intersystem crossing from T_1 to S_0.Therefore,its spin-flip efficiency may be lower.The second crossing point,CP3will again change its spin multiplicity from the singlet state to the triplet state in the Co-Cr bond activation pathway,leading to a decrease in the barrier height of~1TS(CF)from19.5 to 9.5 kcal/mol(1cal=4.182 J),and the efficiency of intersystem crossing from S_0 to T_1 is high because the larger spin-orbit coupling(SOC)matrix elements will result in the overpopulations of the three sublevels of T_1(3.30×10~(-1),3.32×10~(-1),and 3.38×10~(-1),respectively).     

部分和模1(mod 1)分布渐近均匀性的收敛速度

设｛Ｘj｝是独立同分布随机变量序列,｛Ｓn｝是其部分和序列,ξ（Ｓn）表示Ｓn的小数部分,本文讨论了ξ（Ｓn）渐近Ｕ［０,１）均匀分布的收敛速度,即估计supB∈B［０,１)｜P(ξ(Ｓn)∈B)-P(U∈Ｂ)｜。     

氢氧焰燃烧合成纳米SnO2/TiO2复合颗粒的形貌与结构

利用预混合氢氧焰燃烧合成了形态和结构不同的SnO2／TiO2复合纳米颗粒,颗粒呈多面体结构,形貌介于球形和立方方形之间,复合颗粒由同为四方晶系的SnO2和TiO2组成。在SnO2／TiO2复合颗粒中存在Sn—O—Ti键,没有出现相分离现象。复合颗粒表面的Ti：Sn(mol：mol,下同)比大于复合颗粒内部的Ti：Sn,而且复合颗粒内部Ti：Sn接近理论值。     

电位异步电路修正项构成法则(英文)

利用开环法获得了电位异步时序逻辑电路的激励变量项和静态变量项的一般与或逻辑表达式,并且在逻辑余式理论的基础上导出了一个和两个外部激励的异步时序电路的全部修正项,最终解决时序险象提供了坚实基础和最有用的前提条件。     

含氧添加剂碳酸二甲酯降低轻型直喷柴油机碳烟的研究

为了研究含氧燃料对发动机性能和排放的影响,在一台Ｆｏｒｄ７６ＰＳＮＡ轻型直喷柴油机上,以发动机台架试验的方法,研究了碳酸二甲酯作为含氧燃料添加剂对对烟度和发动机性的影响。结果表明,在发动机燃油和燃烧系统不变的条件下,随着ＤＭＣ在柴油中添加比例的增加,排气烟度逐步下降。热效率提高,但发动机功率略有下降。     

K-N黑洞视界极点处二级无限小邻域的度规

利用极限方法得到了Ｋｅｒｒ－Ｎｅｗｍａｎ（Ｋ－Ｎ）黑洞视界极点处二级无限小领域的时空度规,并且证明这个时空度规是以常角速度转动的Ｒｉｎｄｌｅｒ度规。