Biomimetic Robust Starch Composite Films with Super-Hydrophobicity and Vivid Structural Colors

The starch composite films (SCFs) will be one of the best alternative packaging materials to petroleum based plastic films, which mitigates white pollution and energy consumption. However, weak mechanical stability, water resistance, and dyeability has hindered the application of SCFs. Herein, a bioinspired robust SCFs with super-hydrophobicity and excellent structural colors were prepared by fiber-reinforcement and assembling SiO₂/Polydimethylsiloxane (PDMS) amorphous arrays on the surface of SCFs. The properties of the designed SCFs were investigated by various methods including scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermo-gravimetric analysis (TGA), a tensile test, contact angle (CA) test, and an optical test. The results showed that the obtained SCFs possessed a higher tensile strength (55.17 MPa) attributed to the formed abundant hydrogen bonds between the molecular chains of the starch, cellulose fiber, and polyvinyl alcohol. Benefiting from the nanostructure with rough surface which were modified by materials with low surface free energy, the contact angle and sliding angle of the film reached up to 154° and 2°, respectively. The colors which were produced by the constructive interference of the coherent scattered light could cover all of the visible regions by tuning the diameters of the SiO₂ nanoparticles. The strategy in the present study not only reinforces the mechanical strength and water resistance of SCFs but also provides an environmentally friendly way to color the them, which shows unprecedented application potential in packaging materials of the starch composite films.     

A CRISPR/Cas9-Based System with Controllable Auto-Excision Feature Serving Cisgenic Plant Breeding and Beyond

Transgenic or genetically modified crops have great potential in modern agriculture but still suffer from heavy regulations worldwide due to biosafety concerns. As a promising alternative route, cisgenic crops have received higher public acceptance and better reviews by governing authorities. To serve the purpose of cisgenic plant breeding, we have developed a CRISPR/Cas9-based vector system, which is capable of delivering target gene-of-interest (GOI) into recipient plants while removing undesired genetic traces in the plants. The new system features a controllable auto-excision feature, which is realized by a core design of embedded multi-clonal sequence and the use of inducible promoters controlling the expression of Cas9 nuclease. In the current proof-of-concept study in Arabidopsis thaliana (L.) Heynh., we have successfully incorporated a GOI into the plant and removed the selection marker and CRISPR/Cas9 components from the final product. Following the designed workflow, we have demonstrated that novel cisgenic plant germplasms with desired traits could be developed within one to two generations. Further characterizations of the vector system have shown that heat treatment at 37 °C could significantly improve the editing efficiency (up to 100%), and no off-target mutations were identified in the Arabidopsis background. This novel vector system is the first CRISPR/Cas9-based genome editing tool for cisgenic plant breeding and should prove powerful for other similar applications in the bright future of precision molecular breeding.     

利用城市垃圾资源发展新型墙体工业

使用“秦砖汉瓦”的观念在人们心目中已经根深蒂固,想要打破这种观念,就需要大力进行推广,2004年是全国贯彻实施国家禁用实心粘土砖有关规定的关键一年,发展新型墙体材料工业,特别有效利用城市垃圾工业及工业废弃物生产环保型的新型墙体材料是我国墙体改革工作中一项重要和艰苦的任务。     

浅谈外墙外保温外饰面砖施工技术

结合工程实例从粘结机理、保温层受力情况、安全系数等方面进行了讨论,初步分析了墙体外墙外保温外饰面贴砖的安全性,提出了在施工中应采取的质量控制措施。     

Three-dimensional graphene and its composite for gas sensors

As a two-dimensional (2D) material,graphene shows excellent advantages in the field of gas sensors due to its inherent large specific surface area and unique el...     

含短纤维胎面胶的混炼工艺

介绍了含短纤维胎面胶的混炼工艺,分析了在混炼过程中短纤维在橡胶中的混合分散模型.指出当短纤维-橡胶复合材料处于最佳黏度状态时,混炼效果最佳.     

Systematic adsorption process of petroleum hydrocarbon by immobilised petroleum-degradation bacteria system in degradation pathways

In order to effectively control petroleum hydrocarbon pollution by immobilisation technology,it is necessary to understanding the degradation pathways of petrol...     

金属铕制备工艺的研究

本文采用正交实验的方法,研究了金属铕的制备工艺条件。实验结果表明,还原－蒸馏温度１１００℃,还原剂过量系数０．３,保温时间１．５小时,金属铕的纯度大于９９．９％,直收率大于９０％