婚前同居、同居蔓延与中国居民的婚姻稳定性:自选择及其变化

基于2010年和2012年的中国家庭追踪调查数据,首先通过全体样本的Cox比例风险模型回归,实证检验中国居民初婚的婚前同居与婚姻稳定性之间的关系;然后基于不同出生世代子样本的回归,检验随着同居的蔓延,自选择变化导致的婚前同居与婚姻稳定性之间关系的变化;最后采用倾向得分匹配法进行样本匹配,通过比较匹配前后回归结果中\"是否婚前同居\"变量系数的变化,以进行自选择效应的识别。研究发现,整体而言,中国居民的婚前同居与婚姻稳定性负相关;对于出生于不同世代的居民,婚前同居与婚姻稳定性之间关系的大小和显著性发生变化,且随着同居在不同世代群组中的蔓延,婚前同居与婚姻稳定性之间的负向关系减弱;自选择效应基本解释了中国居民的婚前同居与婚姻稳定性之间的负向关系。国家社科基金青年项目“民族地区实现2020年减贫目标的距离估算与精准扶贫政策研究”(15CMZ029);;四川省教育厅人文社会科学重点项目“高离婚率背景下80后婚前同居行为研究”(18SA0264

婚前同居与中国女性的婚姻稳定性:自选择效应还是测度问题

大多研究发现,婚前同居与婚姻稳定性负相关,其中自选择效应和测度问题被视为二者负向关系的主要致因。基于2014年中国家庭追踪调查的女性样本,实证分析了婚前同居和中国女性婚姻稳定性之间的关系,并进一步检验了自选择效应和测度问题在其中作用的相对大小。研究结果显示:总的来说,中国女性的婚前同居与婚姻稳定性负相关;随着同居在改革开放前后出生的女性中的蔓延,婚前同居与婚姻稳定性的负向关系消失;自选择效应基本主导了中国女性婚前同居与婚姻稳定性之间的负向关系;虽然测度问题也推动了中国女性的婚前同居与婚姻稳定性关系的负向变化,但与自选择效应相比,测度问题的影响要小得多。四川省教育厅人文社会科学重点项目“高离婚率背景下80后婚前同居行为研究”(18SA0264

国外同居问题研究述评:与婚姻比较的视角

伴随着西方主要国家同居的快速蔓延,同居现象近年一直是国外学术研究的热点。鉴于同居和婚姻之间的密切关系,对同居问题的研究大多是基于\"与婚姻比较\"的视角。在此视角下,有关同居的研究主题主要包括同居的测度与蔓延、同居者的个体特征和同居的原因、同居与婚姻的关系及其对婚姻稳定性的影响以及同居与孩子的关系等几个方面。在已有研究的基础上,今后需进一步探讨的问题包括更广泛的有关同居的后果或影响,连续和长期同居问题以及特定群体的同居问题等。四川省教育厅人文社会科学重点项目“高离婚率背景下80后婚前同居行为研究”(18SA0264

中西方节日认同:群体差异与影响因素

基于中国综合社会调查2013年度数据,从群体差异与影响因素两个方面,定量考察了中国居民对中西方节日的认同。研究结果显示,以过节比重为标准,中国节日的影响力排序为春节、中秋节、端午节、清明节、元旦节,西方节日的影响力排序为圣诞节、情人节、愚人节。在我国,中国节日的影响力仍大大高于西方节日。不同区域,居住地类型和出生年代的群体对四大中国传统节日(春节、中秋节、端午节、清明节)均拥有较高且差异不大的认同,但对西方节日和元旦节的认同却表现出明显的群体差异。整体而言,中国传统节日认同受出生年代、家庭年收入、婚姻状况、教育水平、居住地类型、居住区域、经济发展水平和父亲教育水平的影响,但对于各个不同的具体节日,其影响因素又有所差异。而对于西方节日,女性,更年轻的出生者,更富裕的家庭,更高的受教育程度,更好的家庭背景等通常意味着有更高的认同

Optimization and characterization of sodium carboxymethyl cellulose with a high degree of substitution prepared from bamboo shavings

从竹材加工剩余物竹屑中提取纤维素,然后制备羧甲基纤维素钠。采用PlACkETT-burMAn(Pb)设计与中心组合法对影响竹纤维羧甲基纤维素钠取代度的6个相关因素进行了研究,结果表明,关键因子为氢氧化钠与纤维素的质量比、氯乙酸钠与纤维素的质量比和醚化时间;建立此三因素对羧甲基纤维素钠取代度影响的二次回归模型,优化得到最佳制备条件是:氢氧化钠与纤维素的质量比为0.8、氯乙酸钠与纤维素的质量比为1.2,醚化时间为2 H。制得羧甲基纤维素钠的黏度为136 M PA·S,取代度为0.93。利用扫描电镜、红外光谱、X射线衍射和热重分析等对制得样品进行表征。结果表明,利用廉价的竹屑可以制备高取代度的羧甲基纤维素钠。The preparation of carboxymethyl cellulose( CMC) with a high degree of substitution( DS) using cellulose from bamboo residues is investigated.The factors affecting DS of CMC are optimized by Plackett-Burman Design( PB) and Central Composite Design.The results of PB indicate that the mass ratio of Na OH and cellulose,the mass ratio of Cl CH2 COONa and cellulose,and the etherification time are the key factors.The quadratic regression model of these three factors is established.The optimal conditions are shown as follows: 0.8 of the mass ratio of Na OH and cellulose,1.2of the mass ratio of Cl CH2 COONa and cellulose,2 hours of the etherification time.Under this condition,CMC with a DS of 0.94 and viscosity of 136 m Pa·s is obtained.The CMC is characterized by SEM,FT-IR,XRD,and TGA.It indicates that cheap bamboo shavings could be used to prepare CMC with a high DS.国家自然科学基金(21303142;31170067); 福建省中青年教师教育科研项目(JA14010); 厦门市海洋经济发展专项资金项目(14GZP59HJ29

Heterologous Expression of the β-Glucosidase and Its Synergistic Hydrolysis of Bamboo with Cellulase

在毕赤酵母gS115中表达东方肉座菌Eu7-22的β-葡萄糖苷酶基因(bgl),获得基因工程菌株bP17。优化bP17収酵产酶条件后,重组β-葡萄糖苷酶活力达121 Iu/Ml。酶学性质研究表明,该酶最适反应温度为70℃,在60℃以下有较好的热稳定性;最适催化PH为5.0,在PH 3.0~8.0之间有较好的稳定性。将异源表达的β-葡萄糖苷酶添加到东方肉座菌的纤维素酶液中协同降解经过预处理的竹纤维,当纤维素酶添加量为fPA 20 Iu/g底物,β-葡萄糖苷酶添加量为bg 6 Iu/g底物时,纤维二糖浓度显著下降,酶解得率达到83.03%,表明重组β-葡萄糖苷酶的加入更有利于纤维素的酶解糖化。The β-glucosidase gene(bglI) from Hypocrea orientalis EU7-22 was cloned and effectively expressed in Pichia pastoris GS115.The-glucosidase activity expressed by recombinant strain BP17 reached 121 IU/mL.The expressed-glucosidase exhibited the optimum catalytic activity at 70°C and pH 5.0.The enzyme exhibited good stability at pH 3.0 ~ 8.0 and remained 65% of its original activity after 1 h at 60°C.The pretreated bamboo cellulose was synergistic hydrolyzed by the cellulases from Hypocrea orientalis EU7-22 and the recombinant β-glucosidase from strain BP17.Supplementing recombinant β-glucosidase greatly reduced the inhibitory effect caused by cellobiose, and the hydrolysis yield was improved to 83.03% with enhanced β-glucosidase activity of 6 IU/g substrate.The results indicated the recombinant β-glucosidase significantly boost the efficiency of saccharification.国家重点基础研究发展计划(2010CB732201); 国家自然科学基金(31170067); 中央高校基本科研业务费专项资金(201112G026

Optoelectronic characteristics of InGaAs (P)/InP strained quantum well and superlattice

利用低压金属有机化合物化学汽相沉积（MOCVd）生长技术在InP衬底上生长IngAAS/InP应变量子阱、超晶格和IngAASP/InP量子阱结构材料，利用77k光荧光（Pl）测量这一应变量子阱和量子阱的光学性质，利用双晶X光测量应变超晶格的性质。InGaAs/InP strained quantum well and superlattice,and InGaAsP quantum well were grown on InP substrate by low-pressure metal organic vapor deposition (LP-MOCVD).The optical characteristics of the strained quantum well and quantum well were studied by photoluminescent (PL) at 77 K, while the characteristics of InGaAs/InP strained superlattice are measured by X-ray double crystal diFFraction.福建省自然科学基金;国家自然科学基

Research Progress of α-Glucuronidase, an Enzyme for Degrading Hemicellulose Side-Chain

半纤维素是自然界中最丰富的可再生资源之一,将半纤维素降解为单糖并转化为燃料或化学品一直是科学界研究的热点。半纤维素是由木糖基主链以及α-葡萄糖醛酸等侧链共同组成的异质多聚体。α-葡萄糖醛酸酶是半纤维素完全降解过程中的关键酶之一,能够水解4-O-甲基葡萄糖醛酸与木糖之间的α-1,2-糖苷键。本文综述了α-葡萄糖醛酸酶的分类、催化机制及晶体结构、酶学性质和基因克隆表达等方面的研究进展,同时对该研究进行了展望。Hemicellulose is one of the most abundant renewable resources in nature.The bioconversion of hemicellulose into biofuels or chemicals is a research hotspot in the world.Hemicellulose consists of a backbone of xylan residues and some branches like glucuronic acid.α-Glucuronidase, which is capable to hydrolysis the α-1,2-glycosidic bond between xylan and glucuronic acid, is one of the key enzyme to degrade hemicellulose completely.The recent research progresses on catalysis mechanism, structure, charaterization, and gene cloning of α-glucuronidase are summarized in this paper.国家自然科学基金(31170067;21303142); 国家重点基础研究发展计划(973计划;2010CB732201); 福建省自然科学基金(2012J05029); 农业部“引进国际先进农业科学技术”项目(2013-Z70

Cloning and heterologous expression of a novel GH10 xylanase gene from Hypocrea orientalis EU7-22

木聚糖酶是降解半纤维素最主要的酶,对于开发可再生生物能源具有重要的应用价值。分别以东方肉座菌(HyPOCrEA OrIEnTAlIS)Eu7-22的基因组dnA和C dnA为模板,利用染色体步移和PCr技术首次克隆获得该菌gH10家族木聚糖酶Ⅲ的基因(XynⅢ),并对其进行生物信息学分析。结果表明:该基因全长1283 bP(gXynⅢ),含有3个内含子;CdS序列为1044 bP(CXynⅢ),编码347个氨基酸,n端含有一个16 AA的信号肽序列;XynⅢ氨基酸序列与TrICHOdErMA PSEudOkOnIngII的EndOXylAnASE具有较高的同源性。经生物信息学分析,XynⅢ成熟蛋白可能含有18个n-糖基化位点,其理论等电点(P I)为6.14,蛋白质分子质量为36.55 ku,属于亲水性蛋白;SWISS-MOdEl建模预测,XynⅢ成熟蛋白中含有11个α螺旋,其核心结构为8个β折叠片围成一个柱状结构。同时将编码成熟蛋白的基因片段MXynⅢ与P PIC9k质粒连接构建表达载体后转化毕赤酵母,对重组子表达产物进行酶活检测显示该基因能在毕赤酵母中表达有生物活性的XynⅢ并分泌到胞外,发酵液中的木聚糖酶活在诱导培养168 H后可达到127.5 Iu/M l。Endo-1,4-xylanase( E.C.3.2.1.8) is the major enzyme to the conversion of hemicelluloses into xylo-oligosaccharide.In this research,a novel GH10 xylanase Ⅲ( xyn Ⅲ) gene was cloned from Hypocrea orientalis EU7-22 by chromosome walking and PCR.The results showed that the DNA fragment( 1283 bp) encoding xynⅢ( gxynⅢ) contained three introns.The CDS of xynⅢ( cxynⅢ) encoded 331 amino acids of putative mature protein and a 16 aa signal in N terminator.The amino acid sequence of xynⅢ is highly homologous with the endoxylanase of Trichoderma pseudokoningii.The bioinformatics analysis showed that the theoretical isoelectric point and the molecular weight of putative mature protein of XYNⅢ were 6.14 and 36.55 ku,respectively.It is a soluble hydrophilic protein containing 18 N-glycosylation sites.The 3D structure predicted with SWISS-Model showed that XYNⅢ protein contained11 alpha helices and 8 extended strands.A recombinant plasmid p PIC9K-xynⅢ was constructed and then transformed into Pichia pastoris.The transformant identified by PCR was induced to produce XYNⅢ enzyme with 1% methanol.And after 168 hours induced expression,the produced crude enzyme was detected to reach a high enzymatic activity of 127.5 IU / m L.国家自然科学基金(21303142;31170067); 福建省海洋高新产业发展专项项目(闽海洋高新[2014]25号); 厦门市海洋经济发展专项资金项目(14GZP59HJ29

Study on Large Scale Precision Measurement Platform for Optical Aspheric Lens

针对光学非球面元件精密面形测量的需要,提出了一种大尺寸精密检测平台的测量与控制技术。通过讨论检测平台离线测量原理,采用高精度直线电机、0.1μM接触式/非接触式测量传感器以及自主开发测量评价软件为核心的软硬件控制方案,完成了大尺寸精密检测平台的设计与搭建,并针对光学非球面元件的测量特点,开发了配套的测量软件,以实现大口径光学非球面元件的面形测量与评价。光学非球面元件的测量实验结果表明:该检测系统可以有效地应用于非球面表面形貌的精密测量。According to the requirement of precision measurement for optical aspheric surface,this paper presents a measuring and control means,which is based on large scale high-precision measurement platform.Through analyzing the off-machine measuring principle,a large scale measurement platform included high-precision linear motors,contacting and non-contacting measurement sensor of 0.1um resolution and a new developed of measuring software,is designed and built.Aiming at the measurement characteristics of optical aspheric lens,measuring software is developed to achieve surface metrology and evaluation for large scale optical aspheric lens.The experiment results indicated that the measuring system has met the needs of high-precision measurement.福建省自然科学基金资助项目(2012J05102); 厦门理工学院高层次人才引进项目(YKJ11029