电信宽带业协同电子商务系统CREC建设探析

介绍了基于ERP、CRM、SCM整合的中国中小企业协同电子商务系统CREC,结合某联通宽带事业部运营特点,建设实施了宽带CREC。实践证明,该系统操作维护简单,可扩展性强,能够快速、动态地响应客户,适合快速成长变化的宽带业务需求。     

食品工业废水处理技术探讨

在简述食品工业废水处理技术现状的基础上,分析了各种工艺的特点及作用,指出厌氧生物处理工艺必将成为食品工业废水处理的主流方向。     

一个适合分布式网络的属性基加密方案

阐述了分布式网络中用加密方法保护交换数据的必要性,结合Ganglia网络,提出了一个适合于分布式网络的基于属性的加密方案.与其他方案比较表明,本方案定长的密文、高效的加解密流程以及良好的灵活性等特点在实际部署引用中具有实用价值。     

水泵吸水口临界淹没深度及其近场水力特性试验研究

通过试验观测水泵吸水管附近旋涡生成、发展的过程,得到了吸水口临界淹没深度与流量的关系式;同时应用粒子图像测速(PIV)技术,对吸水口近区流场进行了多方位、多断面连续拍摄,获取了全场瞬时及时均的流速场和涡量场,定量显示了吸水口周围流速分布、旋涡位置及大小等水力特性.     

LTE上行链路高速铁路应用场景中的频偏估计方法

提出了一种长期演进(LTE)上行链路频偏最大似然(ML)估计算法,并通过定量分析该算法与基于2个训练序列相差的频偏估计算法(相差法)的估计性能,提出了一种联合频偏估计算法.仿真结果表明:与相差法相比,所出提的ML估计算法与联合估计算法的频偏估计范围均能够覆盖高速铁路应用场景中的最大频偏,且ML估计算法不受LTE上行链路跳频传输的影响;在信噪比10 dB且少于4个用户的情况下,2种算法均能够提供10-4或更小的归一化频偏估计均方误差;在单用户情况下,联合估计算法比ML估计算法的均方误差在信噪比上提高了近5 dB.     

小鼠Bpi条件基因打靶载体的构建和鉴定

目的构建小鼠Bpi条件基因打靶载体,为建立Bpi条件基因打靶小鼠模型和深入研究Bpi基因功能奠定基础。方法采用Cre/LoxP系统,选择小鼠Bpi基因第2、3外显子作为条件性敲除的目的片段,并在其两侧插入LoxP位点;运用LA-PCR技术,以129品系小鼠ES细胞基因组DNA为模板分步扩增包括Bpi第2、3外显子(中间同源臂)和上游同源臂在内的3.1 kb基因片段以及下游同源臂4.9 kb基因片段;构建pBSKⅡ-5SLoxP和ploxPFRTNeo-3L重组质粒,将前者酶切产物(3.1 kb)与酶切后的ploxPFRTNeo-3L质粒相连获得Bpi条件基因打靶载体。结果经多个限制性内切酶酶切鉴定和测序证实,构建的pBSKⅡ-5SLoxP、ploxPFRTNeo-3L重组质粒和Bpi条件基因打靶载体结构正确,与设计相符。结论成功构建了小鼠Bpi条件基因打靶载体。     

Impaired hydroxylation of 5-methylcytosine in myeloid cancers with mutant TET2

TET2 is a close relative of TET1, an enzyme that converts 5-methylcytosine (5mC) to 5-hydroxymethylcytosine (5hmC) in DNA. The gene encoding TET2 resides at chromosome 4q24, in a region showing recurrent microdeletions and copy-neutral loss of heterozygosity (CN-LOH) in patients with diverse myeloid malignancies. Somatic TET2 mutations are frequently observed in myelodysplastic syndromes (MDS), myeloproliferative neoplasms (MPN), MDS/MPN overlap syndromes including chronic myelomonocytic leukaemia (CMML), acute myeloid leukaemias (AML) and secondary AML (sAML). We show here that TET2 mutations associated with myeloid malignancies compromise catalytic activity. Bone marrow samples from patients with TET2 mutations displayed uniformly low levels of 5hmC in genomic DNA compared to bone marrow samples from healthy controls. Moreover, small hairpin RNA (shRNA)-mediated depletion of Tet2 in mouse haematopoietic precursors skewed their differentiation towards monocyte/macrophage lineages in culture. There was no significant difference in DNA methylation between bone marrow samples from patients with high 5hmC versus healthy controls, but samples from patients with low 5hmC showed hypomethylation relative to controls at the majority of differentially methylated CpG sites. Our results demonstrate that Tet2 is important for normal myelopoiesis, and suggest that disruption of TET2 enzymatic activity favours myeloid tumorigenesis. Measurement of 5hmC levels in myeloid malignancies may prove valuable as a diagnostic and prognostic tool, to tailor therapies and assess responses to anticancer drugs.     

He(Ar)低能FIB研磨Si薄膜的纳米孔洞溅射产额的计算

利用蒙特卡罗方法计算氦离子和氩离子在各种参数下(离子能量、入射角度)入射硅材料表面的溅射产额.计算了硅材料表面的溅射产额对离子数目、离子能量、入射角度与He离子和Ar离子的数量依赖关系,并对模拟结果进行分析.当入射离子数量为2000个,入射能量为3keV,入射角度为84°时,He离子产生的溅射产额最大值是1.30Atoms/ion;当入射角度为78°时,Ar离子产生的溅射产额最大值是8.91Atoms/ion.     

红树林土壤中脂肪酶产生菌的筛选及酶学性质

从福建龙海红树林区土壤中分离获得9株产脂肪酶的细菌,经16S rDNA序列分析表明分别属于红球菌属(Rhodococcus)、库克菌属(Kocuria)、假单胞菌属(Pseudomonas)、芽胞杆菌属(Bacillus)和微小杆菌属(Exiguobacteri-um).对9株细菌所产的脂肪酶进行酶学性质研究,结果显示这些酶的最适作用温度在25~35℃、最适作用pH值在8~10,其中L13菌株所产脂肪酶(L′13)具有适应温度和pH范围较广、对多种金属离子耐受性强、能有效降解不同底物等特点,在环境保护和工业生产方面具有良好的应用前景.     

Microstructure and mechanical properties of AZ91 magnesium alloy subject to deep cryogenic treatments

AZ91 magnesium alloy was subjected to a deep cryogenic treatment. X-ray diffraction (XRD), scanning electronic microscopy (SEM), and transmission electronic microscopy (TEM) methods were utilized to characterize the composition and microstructure of the treated samples. The results show that after two cryogenic treatments, the quantity of the precipitate hardening β phase increases, and the sizes of the precipitates are refined from 8–10 μm to 2–4 μm. This is expected to be due to the decreased solubility of aluminum in the matrix at low temperature and the significant plastic deformation owing to internal differences in thermal contraction between phases and grains. The polycrystalline matrix is also noticeably refined, with the sizes of the subsequent nanocrystalline grains in the range of 50–100 nm. High density dislocations are observed to pile up at the grain boundaries, inducing the dynamic recrystallization of the microstructure, leading to the generation of a nanocrystalline grain structure. After two deep cryogenic treatments, the tensile strength and elongation are found to be substantially increased, rising from 243 MPa and 4.4% of as-cast state to 299 MPa and 5.1%.