中国国际收支双顺差形成的微观机理探究——基于全球价值链视角的实证分析

我国双顺差形成及外汇储备持续扩大的原因与中国在全球价值链中的定位有密切的关系。中国在加入GVC时,由于处在"世界工厂"的低端位置,形成了以外资代工为主的生产贸易模式。中国国际收支双顺差现象只是中国经济嵌入GVC模式的货币镜像。从微观视角探究到的双顺差的国际分工基础,对中国汇率政策的制定具有重要的参考价值

Anatomic and radiograph study of double-bundle anterior cruciate ligament reconstruction

目的测量并研究标准膝关节侧位X线片上前交叉韧带(ACl)股骨止点的相关骨性标志数据,为临床ACl重建提供参考。方法对10例成人膝关节标本进行解剖观察,标记ACl股骨止点前内侧束和后外侧束,摄标准膝关节正侧位X线片,利用图像分析软件测量两束止点中心(前内侧束为A点,后外侧束为b点)与股骨后髁弧形中心(I点)的距离,测量A点与过顶点、b点与过顶点的距离。结果解剖观察表明,ACl在中段根据其纤维走行及屈伸过程中的松紧变化,较易分为2束。A点与I点的距离为3.08~7.33(5.40±1.56)MM,b点与I点的距离为3.42~7.15(5.40±1.31)MM,A、b点与I点的距离差异无统计学意义(T=0.198,P=0.848)。A点与过顶点的距离为7.60~12.40(9.90±1.60)MM,b点与过顶点的距离为13.50~18.60(15.70±1.70)MM。结论股骨外髁弧形中心(单束重建等长点)与ACl前内侧束、后外侧束中心等距,支持单隧道双束重建ACl的理论要求。Objective To measure and study the distance relationship between femoral footprint ACL and femoral condylar landmarks on a standard knee joint lateral X-ray, in order to provide reference for clinical ACL reconstruction.Methods Ten human cadaveric knees disposaled in formalin were anatomized.A mark was made on the footprint of anterior cruciate attachment, ACL was divided into anteromedial bundle and posterlateral bundle, and a standard knee joint lateral X-ray was taken.The distance between the centre of two bundle(the anteromedial bundle was A point, the posterolateral bundle was B point) and the centre point of femoral condyle arc were measured by using the image analysis software.The distance between theover-the-topposition and point A, point B were measured.Results The anatomy observation showed that, in the middle of the ACL according to elastic change of the fiber and the flexion and extension process, it was easy to be divided into two bundles.The distance between point A and point i was 3.08-7.33(5.40 ±1.56) mm, the distance between point B and point i was 3.42-7.15(5.40±1.31)mm.There were no significant differences(t =0.198,P =0.848).The distance between point A and over-the-topposition was 7.60-12.40(9.90±1.60)mm, and the distance between point B and over-the-topposition was 13.50-18.60(15.70±1.70)mm.Conclusion The distance between the centre of AM, PL and the centre point of femoral condyle arc is equal, which supports the theory of the single tunnel double bundle reconstruction.厦门市科技计划项目(3502Z20114036

我国股份公司法人治理结构问题调查

在我国企业改制中,股份公司法人治理结构的确立、规范及有效运转是一个重点,也是一个难点。由于经济体制尚处于转轨过程中,各种规章制度不完善,从而导致了我国股份公司法人治理结构各个组成要素之间的制衡关系不完备,使法人治理结构未能起到应有的作用

THE LABORATORY CULTURE AND REPRODUCTION of TWO IANCELETS IN XIAMEN

国家自然科学基金(30570208);教育部高等学校博士学科点专项科研基金(20070384041)资

暴露测年样品中26Al和10Be分离及其加速器质谱测定

在已有实验流程基础上,建立并优化了石英样品中Be和Al提取、纯化等实验流程,设计的流程条件实验包括实验试剂、器皿和离子交换柱选择、离子交换树脂分离Be和Al时酸浓度选择等。结果表明,选择钢铁研究总院研制的~9Be标准溶液作为~(10)Be样品制备的载体;使用一次性实验器皿;选用4 cm规格的离子交换柱;用0.05 mol/L草酸和0.75 mol/L盐酸混合溶液洗脱吸附于阴离子树脂上的Al,可有效提取、纯化样品中的Be和Al。加速器质谱(AMS)测量结果显示,13组化学空白的~(10)Be/~9Be和~(26)Al/~(27)Al比值平均值分别为7.48×10~(-15)和1.96×10~(-15),与国内已有宇宙成因核素实验室的结果(5×10~(-15)~8×10~(-15))具有可比性。电感耦合等离子体发射光谱(ICP-AES)的测量结果表明,Be、Al回收率分别达90%和60%。基于新建立的实验流程分析了祁连山北侧金佛寺的一个岩石样品,获得了~(10)Be和~(26)Al的暴露年代分别为(10.7±1.0)ka和(10.0±1.2)ka,与前人研究结果一致

氧化石墨烯改性高温环氧树脂基碳纤维复合材料的热性能与力学性能

采用湿法预浸技术和模压工艺,制备了氧化石墨烯(GO)改性碳纤维/环氧树脂(CF/E54-DDS)混杂复合材料,利用差示扫描量热分析(DSC)、动态热机械分析(DMTA)、无损C扫描等开展了GO对复合材料的热固化性能、凝胶工艺性、动态热机械性能以及抗冲击损伤性能等的影响研究。结果表明,GO结构中的羟基、羧基会促进改性树脂体系的固化反应,GO/E54-DDS的固化反应比E54-DDS的提前,反应变得和缓,且会加速固化反应的进行;在GO含量小于0.5%时,GO的活性基团可增加改性体系的交联密度而提高复合材料的玻璃化转变温度,但GO含量大于0.8%时,会因DDS在固化网络结构中的占比下降较大,反而降低复合材料的玻璃化转变温度;GO/CF/E54-DDS预浸料比CF/E54-DDS表现出更好的浸润效果;CF/E54-DDS复合材料破坏后碳纤维表面光洁,破坏主要发生在碳纤维与树脂基体的界面,而GO/CF/E54-DDS复合材料破坏后,碳纤维表面紧密粘附着GO/E54-DDS固化物,破坏主要发生在碳纤维织物层间的GO/E54-DDS区域;GO的存在提高了GO/CF/E54-DDS复合材料抵抗横向裂纹和纵向裂纹扩展的能力,复合材料的损伤投影面积和凹坑深度减小,提高了冲击后压缩强度。航空科学基金(2016ZF68011);;福建省科技创新平台建设计划(2014H2006);;福建省自然科学基金(2015J01222);;厦门大学石墨烯工业技术研究院资助项目(2014I2005

以信用监管为核心 打造新型监管机制

背景材料:近年来,以信用监管为核心的新型监管制度在各个领域被广泛运用。5月15日,《司法部关于印发开展证明事项告知承诺制试点工作方案的通知》确定在13个省(市)和5个国务院部门开展试点,强调转变监管方式,加强信用监管,切实减少繁琐证明。今年3月,国务院办公厅印发《关于全面开展工程建设项目审批制度改

人乳头瘤病毒16型病毒样颗粒的制备及其免疫原性研究

利用PCR技术从HPV16阳性阴道分泌物标本中获得HPV16 L1基因片段,并将其插入表达载体pTO-T7中,构建重组表达质粒pTO-T7-HPV16-L1;以该重组质粒转化大肠杆菌ER2566并表达HPV16 L1蛋白;所表达的HPV16 L1蛋白经过硫酸铵沉淀、离子交换层析和疏水相互作用层析等纯化步骤后,HPV16 L1纯度达到98%以上,并可在体外装配为直径50nm的病毒样颗粒;动物免疫原性研究结果显示,该病毒样颗粒可诱导高滴度的针对HPV16的中和抗体。上述研究结果表明通过大肠杆菌表达系统制备的HPV16病毒样颗粒具有纯度高,与天然病毒颗粒形态高度相似的特点,并具有高度免疫原性,可以应用于HPV16病毒样颗粒的结构功能研究及HPV16疫苗研发等领域

Acrosome Reaction of Sperm in the Mud Crab Scylla serrata as a Sensitive Toxicity Test for Metal Exposures

【英文摘要】In order to test the sensitivity of the sperm cell of the mud crab Scylla serrata to heavy metals, the toxic effects of Ag+, Cd2+, Cu2+, and Zn2+ on the acrosome reaction (AR) were studied by artificially inducing the AR of sperm exposed to heavy metals, counting the AR rates by light microscopy, and observing structural changes in sperm by transmission electron microscopy. The AR in S. serrata occurs at two stages. The first stage (ARI) is the eversion of the subacrosomal material. The second stage (ARII) is the ejection of the acrosomal filament. The results showed the EC50 values of the AR based on (ARI + ARII)% for Ag+, Cd2+, Cu2+, and Zn2+ were 10.02, 2.14, 13.69, and 2.21 μg/L, and the EC50 values based on ARII % of Ag+, Cd2+, Cu2+, and Zn2+ were 1.96, 0.20, 1.46, and 0.34 μg/L. The order of toxicity is Cd2+ > Zn2+ > Cu2+ > Ag+ based on the percentage of reacted sperm at the second stage. Sperm cells exposed to heavy metals showed an increased rate of swelling, shape irregularities, and the acrosomal filament of some sperm cells was, crooked, ruptured, and even dissolved. The AR of the sperm cell from S. serrata is more sensitive to the tested heavy metals compared to sea urchin sperm cell toxicity tests