阻碍物

Results showed that the only intact basement membrane complex was found on the luminal surface of the ECM deried from the urinary bladder and that the basement membrane was an effectie barrier to penetration of the scaffold by the seeded cells.

结果表明，只有在膀胱来源的ECM支架内表面才发现了完整结构的基底膜复合物，而且这种基底膜结构是支架阻碍种植细胞渗透生长的有效屏障。

The crystallization of the blends were investigated by wide angle X-ray diffraction and polar light microscope . The results show that PPEKK in the blends deforms the crystallization of PPS but don't change its crystal structure.

用广角X射线衍射和偏光显微镜对共混物的结晶性能进行了研究，结果表明PPEKK对共混物中PPS的结晶作用有阻碍作用，但没有改变PPS的晶相结构。

A mass of DMO in the transesterification course inhibited the disproportionation which has a small equilibrium constant. As a result, selectivity and yield of DPO were low.

酯交换反应中由于反应物DMO的大量存在阻碍了平衡常数较小的歧化反应的进行，使得DPO选择性和收率较低。

The effects of different factors on the laser-induced graft polymerization on the PET surface were analyzed, and the mechanisms were discussed. The factors were: 1 Monomers with smaller molecules resulted in better modification than polymeric monomers. Acrylamide monomer was chosen as hydrophilic modifier finally; 2 Higher concentration of the monomer solution favored the graft reaction; 3 With the increasing laser fluence, the surface hydrophilicity of PET films increased at first, then decreased. More laser pulses led to a more hydrophilic surface; 4 Benzophenone as a photosensitizer hindered the graft polymerization; 5 The homopolymer retardant of ammonium iron sulfate hexahydrate in a proper concentration retarded the formation of homopolymers and promotes the graft copolymerization; 6 The solvent of monomer solution also affected the graft reaction. Different solvents functioned in different ways. Ethanol can promote the graft reaction because of the activity of hydrogen in its structure; 7 pH value of the monomer solution affects the polymerization rate, and a lower pH value was favorable to the graft reaction.

这些影响因素的作用分别为：1小分子单体的表面改性效果好，确定以丙烯酰胺为亲水性改性单体；2较高的单体溶液浓度有利于接枝反应；3激光能量密度增大，薄膜表面亲水性先显著增强，后又减弱；激光脉冲次数越多，改性后表面亲水性越强；4光敏剂BP对PET表面接枝聚合反应有阻碍作用；5适当浓度的均聚物抑制剂六水合硫酸铁铵能减少单体均聚物的生成，促进接枝聚合；6单体溶液的溶剂也影响接枝聚合的反应进程，不同溶剂的影响作用原理不同，含较活泼氢的乙醇能促进接枝反应；7溶液pH值影响单体聚合速率，pH值较低有利于接枝反应。

The substituted half-sandwich titaconece with bulky alkoxyl group [CpTiC1〓 or CpTi 〓] or indene ring can not be fluorinated by BF〓·Et〓O under the selected condition, but still coordinates with the BF〓, this coordination then enhances the steric effect that stabilizes the precursor and hinders the reduction of the Ti to the Ti species, reflected in the decrease in polymerization activity.

但是这个转化受主催化剂分子的空间位阻和聚合反应温度的影响，当主催化剂为大位阻的烷氧基取代茂钛络合物或茚钛络合物时，在一般的聚合温度下BF〓不能对它们进行氟化，但可以和其中的OR配位，这种配位进一步加剧了空间位阻，从而阻碍了活性中心的形成，导致催化活性的下降。

Though recently ionic materials composed of DNA and polyether-derivatized transition metal complexes were reported, dissolution of proteins and carbohydrates in ionic liquids is generally hindered by their insolubility.

虽然最近离子材料组成DNA和聚醚衍生物过渡金属配合物的报告，溶解蛋白质和碳水化合物的离子液体通常是阻碍其insolubility 。

In addition in the complexes, Ar atom has apparent obstruction to the internal rotation of the methyl group.

另外，在复合物内部，Ar原子对甲基氟苯中的CH3内转动有明显的阻碍作用。

A1l the thick adsorption layer,large space steric hindrance,thick solvate layer and stable ξ-potential of ASP adsorbed on cement particles resist the flocculation of cement particles.In addition the early stage hydration of cement is restrained because the—OH ,—NH2 in ASP can suppress the formation of hydrated products such as C-S-H ,Ca2 and ettringite crystals through forming unstable complex compound with Ca2+.So ASP has excellent plasticity-retention capability of concrete.

由于ASP在水泥颗粒表面的吸附层较厚、空间位阻较大、溶剂化层较厚及ξ-电位较稳定等原因，阻碍了水泥颗粒间的凝聚；同时由于ASP含有的—OH，—NH2等官能团与水化产生的Ca2+形成不稳定的络合物，抑制了水化产物C-S-H，Ca2和钙矾石等结晶体的形成，从而抑制了水泥的早期水化，故ASP具有良好的保塑性能。

It is the fluorosilicic ion that exsits in the slurry and plays an important role in flotation, fluorosilicic ion not only reacted with Fe〓 on the surface of aegirine to form ionic compound, but also formed stable Si-F bond in Si-O etching reaction. Only ionic compound was obtained when it was attached to hematite surface according to the theories of coordination chemistry, Compared with SiF〓, Fatty acid ion preferentially acts with Fe〓 on the minerals surface, therefore, SiF〓 Can't obstruct the adsorption of collector on the surface of hematite completly, but can reduce the flotation recovery of aegirine selectively.

运用FTIR、XPS等测试方法仔细研究了氟硅酸盐抑制剂对含铁硅酸盐钠辉石的选择性抑制作用机理，氟硅酸盐在弱酸性条件下对赤铁矿浮选的抑制作用很微弱，而对含铁硅酸盐钠辉石强烈抑制，从而扩大了两者之间的浮选差异；SiF〓是矿浆中起抑制作用的主要成分，SiF〓不仅与钠辉石表面的Fe〓形成离子型配合物，而且还与Si-O键形成稳定的Si-F共价键，而与赤铁矿表面只能形成离子型配合物，根据晶体配位场理论，与SiF〓相比较羧酸根离子将优先与矿物表面Fe〓发生配位作用，因此SiF〓的存在并不能完全阻碍捕收剂在赤铁矿表面的吸附作用，却能够选择性地抑制钠辉石的上浮。

The results showed the addition of PPS did not decrease the thermal performance but decreases the heat deformation temperature of PPES/PPS blends. The crystallinity of PPS was hindered with the increasing of PPES contents, the crystal lattice flaws of PPS occurred and the perfect spherocrystal could not appear when the mass fraction of PPES was 80%. The annealing process was favorable to the increase of the heat deformation temperature and the formation of perfect spherocrystal of PPS.

热失重研究表明，在所组成范围内PPS的加入并未降低共混物的热性能，但使共混物的热变形温度有所降低；PPES的加入使PPS的结晶受到阻碍，当PPES质量分数达80%时，PPS产生了晶格缺陷，从而不能形成完善的球晶，退火过程有利於提高共混物的热变形温度，使PPS形成更完善的球晶。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。