低信噪比下RSC码快速迭代寻优识别算法

为了解决现有算法在RSC码多项式参数识别过程中,实时性不好和容错性差两大缺点,提出了具有低信噪比适应能力的RSC码快速迭代识别算法.首先根据RSC码元之间的线性约束关系,定义了双曲正切符合度概念,该概念能够表征在某一多项式参数下,截获码元之间的线性关系成立的可能性大小;其次将截获码元总的双曲正切符合度值作为代价函数,然后将待识别的多项式参数的概率值作为代价函数自变量,从而将RSC码参数识别问题转化为多元函数极大值求解问题;最后利用变步长梯度上升方法,在有限次的迭代下,完成在连续概率空间中代价函数极大值求解,最终完成RSC码参数识别.提出的算法收敛速度快且稳定,除了具有较强的低信噪比适应能力外,其计算量与编码器寄存器个数以及码元路数成平方倍数增长.仿真实验表明：提出的算法最多在第5次迭代时,就能完成参数的收敛,同时低信噪比的适应能力较强,即使在0dB条件下,RSC码多项式参数识别率能达到90%以上;与现有的相关算法相比,所提算法的低信噪比适应能力提高了近3dB,同时完成一次参数识别的时间大大降低.     

聚半乳甘露糖在纸浆中的吸附和抗离子干扰的研究

聚半乳甘露糖（galactomannan,GM）是一种异质多聚糖半纤维素,与纤维素结构类似,能快速吸附到纤维素表面,同时吸附细小纤维、胶体糖类物质以及矿物填料,是一种高性能的造纸湿部化学助剂。本研究利用废液浊度研究了GM对细小纤维和填料的吸附特性以及抗离子干扰的影响。结果表明,相比于阳离子淀粉（CS）添加剂,即使添加量较少,如0.3%-0.5%,GM对细小纤维和矿物填料都有较强的吸附作用,吸附稳定性好;甚至在离子富集的白水系统中,GM对离子干扰不敏感,而CS却极易受到离子垃圾的影响,从而导致两者的增强效果差别很大。造成这种现象的原因除氢键作用外,还与分子链结构构型产生的范德华力有关。由于GM分子链具有顺式结构,具有较强偶极矩叠加诱导力,导致GM大分子有较强的极性,即使系统污染较大,干扰因素较多,但对GM大分子的吸附力影响却有限。因此,相比CS等湿部聚合物添加剂,由于GM具有较高的吸附絮凝特性,将会较大幅度降低COD,有利于高速纸机的白水封闭循环系统。     

Photochemical modulation of DNA conformation by organic dications

A group of azobenzene derivatives containing two quaternary ammonium groups with various intercharge distances between them was synthesised and used to control photochemically the conformation of genomic DNA by switching the distance between cationic ammonium groups in the dications. It was found that isomerisation of either dication from the trans form to cis resulted in an increase in the dication's efficiency for DNA compaction; this is associated with a decrease in intercharge distance between ammonium groups and leads to a better match of the binder's cationic groups to adjacent phosphate groups of DNA. Ammonium dications have several important advantages over the photosensitive surfactant type of diazobenzene reported earlier: they can be used at significantly lower (>100-fold) concentrations than photosensitive surfactants, and DNA conformation control can be performed over a broader concentration range of dications. The influence of intercharge distance in photosensitive dications on photo-induced DNA binding discrimination is discussed, and the molecular mechanism is proposed.     

From crumple conformation to gel configuration of reduced graphene oxide: The cation induction engineering

Spatial conformation of condensed state graphene is fundamentally important for its material properties, while its rational design or control is of great challenge. Herein, reduced graphene oxides with diverse crumple conformations are synthesized facilely and effectively by using electrostatic force from cation-oxidized functional group and cation-π interactions through NaCl/MgCl₂/AlCl₃ assisted hydrothermal reduction. A phase map for crumple conformation and gel configuration transitions of the reduced graphene oxides is established, where intramolecular effect of mono-valent cation and intermolecular effect of di-/tri-valent cations are captured and utilized to tune the crumple degree or gelation process. Desired material features, including specific surface area and surface functional groups, can be finely modulated via crumple conformation or cation interaction, and enable the reduced graphene oxides to present an outstanding rate capability of 68.8% and unparalleled areal capacitance of 98.0 μF/cm² at 100 A/g in symmetric aqueous supercapacitors. This study broadens the topological behavior spectrum and stimulates the conformation engineering methodology of reduced graphene oxides, facilitating the development of novel graphene-based materials.     

Applying γ‐Substituted Prolines in the Foldon Peptide: Polarity Contradicts Preorganization

Rational choice of chemical modifications to proline residues allows the preorganization principle to be exploited for more stable assembly of the foldon domain as a tag for trimerization. With systematic knowledge of how chemical and steric variations of the ring substituents affect the relative stabilities of exo and endo puckers, the preorganization principle should then be usable in biotechnologically synthesized foldon mutants and applicable for protein tagging elsewhere.     

注射成型物结构与性能的层析图像法研究

基于聚合物成型机理的三维层析数字图像化原理,对注射成型聚合物进行了X射线层析图像实验,在实验的基础上,详细分析了注射成型中聚合物层析结构形态特点,并从实验和理论两方面获得注射成型聚合物层析结构与其物理特性－－密度及其分布和取向之间的关系。     

Detection of quantitative trait loci in Danish Holstein cattle affecting clinical mastitis, somatic cell score, udder conformation traits, and assessment of associated effects on milk yield

The aim of this study was to 1) detect QTL across the cattle genome that influence the incidence of clinical mastitis and somatic cell score (SCS) in Danish Holsteins, and 2) characterize these QTL for pleiotropy versus multiple linked quantitative trait loci (QTL) when chromosomal regions affecting clinical mastitis were also affecting other traits in the Danish udder health index or milk production traits. The chromosomes were scanned using a granddaughter design where markers were typed for 19 to 34 grandsire families and 1,373 to 2,042 sons. A total of 356 microsatellites covering all 29 autosomes were used in the scan. Among the across-family regression analyses, 16 showed chromosome-wide significance for the primary traits incidence of clinical mastitis in first (CM1), second (CM2), and third (CM3) lactations, and SCS. Regions of chromosomes 5, 6, 9, 11, 15, and 26 were found to affect CM and regions of chromosomes 5, 6, 8, 13, 22, 23, 24, and 25 affected SCS. Markers on chromosomes 6, 11, 15, and 26 can be used to perform marker-assisted selection on CM without a direct negative selection on milk yield, because no effects were detected on the milk traits. Comparing multi-trait models assuming either a pleiotropic QTL affecting 2 traits or 2 QTL each affecting 1 trait gave some evidence to distinguish between these models. For Bos taurus autosome 5, the most likely models were a pleiotropic QTL affecting CM2, CM3, and SCS, and a linked QTL affecting fat yield index. For Bos taurus autosome 9, the most likely model is a pleiotropic QTL affecting CM1 and CM2 at approximately 8 cM.     

Genetic analysis of locomotion and associated conformation traits of Holstein-Friesian dairy cows managed in different housing systems

The objectives of this study were to determine the influence of housing on lameness-related linear and composite traits, and to estimate heritabilities of the traits and correlations among them. Data comprised 156,770 national type evaluation records of pedigreed first-lactation Holstein-Friesian cows that calved from 2000 through 2006 and were classified in different housing systems—cubicles, straw yards, slatted or loafing yards, and on pasture. Locomotion score (LOCO), rear leg, side view (RLS), foot angle (FA), bone quality (BO-NEQ), legs and feet (L&F), and mammary composite (MAMM) were the traits measured. Data were analyzed by REML, using an animal model. In general, cows in grazing systems had better locomotion, straighter RLS, steeper FA, flat and more refined bones, better L&F, and better mammary systems compared with cows housed in other systems. Estimates of heritability ranged from 0.11 for LOCO to 0.31 for MAMM. Bone quality had the highest heritability (0.23) of the traits associated with L&F. Genetic associations between BO-NEQ and LOCO, L&F, and MAMM were moderate to high (0.30 to 0.50), but estimates between BONEQ and RLS and FA were not significantly different from zero. Locomotion score had a very high genetic (0.98) and phenotypic (0.78) correlation with L&F, indicating that both traits are genetically the same. On the basis of the genetic parameters, including BONEQ in a selection index as a predictor of longevity is promising, but further information on its association with longevity is required.