X65管线钢焊接接头抗H2S应力腐蚀开裂性能

中海石油(中国)有限公司天津分公司在渤海湾某油田开展了天然气利用项目,天然气外输海管选用国产X65管线钢手工电弧焊接敷设完成.随着油田不断深入开发,伴生天然气中H2S含量持续增长,该海底管道特别是焊接接头等薄弱部位在运行过程中面临着H2S应力腐蚀开裂风险.根据NACE相关标准方法研究了X65管线钢焊接接头抗HB/HIC/SSCC性能,并对SSCC发生机制进行了探讨.研究结果表明:该天然气外输管道所选的国产X65钢焊接接头具有优良的抗H2S应力腐蚀性能,在管道敷设达标及目前运行工况条件下发生硫化物应力腐蚀开裂的风险较小.     

辽西地区土地利用变化对生态安全的影响——以朝阳县为例

基于RS和GIS技术,以朝阳县为例,研究辽西地区土地利用变化及其结构特征,通过模糊关联度法和多级加权求和模型,生成2000和2010年土地生态安全等级图.研究结果表明:10年来朝阳县土地利用变化剧烈,居民工矿用地与交通用地大幅增加,水土流失率下降,生态安全有逐渐提高的趋势.生态安全等级较高区域主要分布在县域中部;生态安全等级中等区域主要分布在县域南部和北部;生态安全等级较低区域主要分布在县域中部少数地区.最后针对生态安全等级的分布格局,提出了生态环境安全的政策建议及改造措施.     

川西茶区4个主栽茶树品种生化性质和适制性的研究

对川西茶区4个主栽茶树品种主要生化成分及其适制性进行分析测定。结果表明:名山白毫和名山213的游离氨基酸总量(3.58±0.52b)%～(3.84±0.39a)%和(3.72±0.09b)%～(3.95±0.88ab)%及20种氨基酸总量27.11～34.66和26.72～33.60 mg/g较高,儿茶素品质指数1518.52～1568.63和1532.73～1597.96也较高,酚氨比4.30～5.76和4.21～5.96较低,具有适制名优绿茶的优良品质;福鼎大白茶次之;福选9号游离氨基酸的总量3.06±0.42b～3.50±0.41b,20种氨基酸总量21.37～27.39 mg/g以及儿茶素品质指数934.25～965.22均低于其余3个供试品种,主要品质成分的含量和配比不理想,感官审评结果得分最低,品质表现一般。     

Effects of binder fibers and bonding processes on PET hollow fiber nonwovens for automotive cushion materials

In this study, nonwoven fabrics were developed for the replacement of polyurethane foams in car interiors, in particular, cushioning materials for car seats. Polyethylene terephthalate (PET) hollow fibers and two types of bicomponent binder fibers were used to manufacture automotive nonwovens by carding processes and then post-bonding processes, such as needle punching or thermal bonding. The physical and mechanical properties of nonwovens were thoroughly investigated with respect to the effects of binder fibers and bonding processes. The tensile strength and elongation for nonwovens were found to be significantly improved by combined needle punching and thermal bonding processes. In addition, the nonwoven cushioning materials were characterized in terms of hardness, support factors, and compressive and ball rebound resilience. The nonwovens showed greater hardness than the flexible PU foam. However, support factors over 2.8 for the nonwovens indicated improved seating comfort, along with better seating characteristics of greater resilience and air permeability in comparison with the PU foam.     

Composites of polyolefin elastomer reinforced with short carbon fiber and its copolymerization conditions

To study the effects of short carbon fiber (SCF) on the properties of the polyolefin elastomers (POEs), we prepared the poly(ethylene-co-1-hexene) (PEH)/SCF composites at different percentages of SCF. We also prepared polyethylene (PE)/SCF composites to compare with PEH/SCF composites. PEH was synthesized by the copolymerization of ethylene and 1-hexene using metallocene catalyst/cocatalyst system. Optimum stirring speed, Al/Zr feeding molar ratio, polymerization time, and polymerization temperature were 700 rpm, 600, 30 min, and 60 °C, respectively. We investigated the morphology of the composites using scanning electron microscopy (SEM) and found that the wettability of SCF in PEH/SCF composites was fairly better than that of SCF in PE/SCF composites. It was observed from mechanical tests that the ultimate tensile strength and tensile modulus of PEH/SCF composites were remarkably enhanced as the SCF content increased, whereas those of PE/SCF composites were a little increased. PEH/SCF composites exhibited lower crystallinity than PE/SCF ones. Thermal stability of the composites was enhanced by the addition of SCF.     

准噶尔盆地西北边缘荒漠植物群落分布的主要环境因子影响分析

针对准噶尔盆地西北边缘的湖积平原荒漠植物群落,选取了具有代表性的盐穗木群落、梭梭群落和白梭梭群落共9个典型群落样地进行调查。通过测定每一样地不同深度的16项土壤理化因子指标,运用聚类分析对土壤指标进行聚类,结果得到与典型群落样地吻合性较好的土层深度是0~35cm的土层。进一步运用除趋势对应分析(DCA)方法,定量的对9个典型群落样地和0~35cm土层的16项土壤理化因子指标进行排序分析,结果表明这一层的土壤因子含量能较好的反映植物群落的分布情况,盐穗木群落、白梭梭群落和梭梭群落分别与土壤总盐、土壤碱性和土壤速N呈正相关。     

论威廉·华兹华斯的“愉快”诗学

威廉·华兹华斯的诗学理念在《抒情歌谣集》序言中有较为完备的阐述,其中表达了一种观念,即诗歌创作所传递的情感应该是一种“愉快”的情感,我们称之为“愉快”诗学思想。以《我好似一朵流云独自漫游》、《廷腾寺》、《我们共七个》等作品为例,从华兹华斯的自然情怀和儿童情结出发,分析出华兹华斯“愉快”诗学的创作原则,即：立足于生命本体需要,坚持生命内在的幸福感与外在自然和社会的和谐。就其核心内涵和社会影响而言,华兹华斯的“愉快”诗学思想对当下文学艺术创作及社会发展变迁,具有一定的现实意义。     

Runx2 promotes osteogenic differentiating C2C12 cells through inhibiting macroautophagy

AIM：To explore the relationship between macroautophagy and Runx2-induced osteogenic differentiation of C2C12 cells.METHODS：The cells of C2C12/Runx2Dox subline were used in the study, which expresses Runx2 in response to doxycycline (Dox). The cells were treated with Dox (10 mg/L) for 0 d, 1 d, 3 d, and 6 d, and the expression levels of LC3b, Beclin-1, p62, and LAMP-2 were detected at each time point using real-time qPCR. The LC3-I/LC3-II ratio was measured by Western blotting. The cells were treated with different concentrations of 3-methyladenine (3-MA) or rapamycin (Rap) for 14 days in the presence of Dox, and the alkaline phosphatase (ALP) activity was measured. The cells were treated with 3-MA (5 mmol/L) or Rap (10 μmol/L) for 1 d, 3 d, and 6 d in the presence of Dox, and the expression levels of ALP and osteocalcin (OC) were detected.RESULTS：The expression levels of LC3b and Beclin-1 were dramatically down-regulated during Runx2-induced osteogenic differentiation of C2C12 cells, and the levels of p62 and LAMP-2 were not changed during this process. The conversion of LC3-I into LC3-II was inhibited. The ALP activity was increased in 3-MA (5 mmol/L)-treated cells, but decreased in Rap (10 μmol/L)-treated cells. The expression levels of ALP and OC were up-regulated by 3-MA treatment and were down-regulated by Rap treatment.CONCLUSION：Runx2 induces osteogenic differentiation of C2C12 cells by inhibiting the formation of autophagosome through down-regulating LC3 and Beclin-1 as well as inhibiting the conversion of LC3-I to LC3-II.     

抗烟草青枯病菌的芽胞杆菌筛选和鉴定

烟草青枯病是由青枯劳尔氏菌Ralatonia so-lanacearum引起的一种土传病害。此病是热带、亚热带地区烟草的主要病害之一,在我国长江流域及其以南烟区普遍发生,其中以广东、福建、湖南、四川及贵州烟区危害较重。烟草青枯病自发现以来,引起了国内外学者的广泛关注。目前,在生产中主要采用化学农药防治,     

Effects of curcumin concentration and temperature on the spectroscopic properties of liposomal curcumin

The spectroscopic properties of liposomal curcumin in pH 7.0 sodium phosphate buffer were studied at various curcumin concentrations and temperatures. At 25 °C, liposomal curcumin exhibited much higher values than free curcumin in absorption maximum, fluorescence maximum, and fluorescence anisotropy. When curcumin concentration was increased from 2 to 20 μM, the values of fluorescence anisotropy of liposomal curcumin decreased gradually, consistent with the reduction of phase transition temperature of liposome. This observation revealed that liposomal curcumin can disrupt the packing of phospholipid bilayer and give a loose and disordered structure. On the other hand, as the temperature was increased from 25 to 80 °C, the relative intensity of maximum absorption of liposomal curcumin showed a more pronounced decrease above the phase transition temperature than lower temperatures, suggesting a weaker curcumin protection from the liquid crystalline phase of phospholipid bilayer than the rigid gel phase. However, it was observed that the fluorescence anisotropy of liposomal curcumin had higher values as the temperature increased. This phenomenon was explained as the result of location change of curcumin toward the core of phospholipid bilayer, although the structure of the phospholipid bilayer tended to be looser at higher temperatures.