Effect of ligand passivation on morphology,optical and photoresponse properties of CdS colloidal quantum dots thin film

In the present report, cadmium sulfide (CdS) colloidal quantum dots (CQDs) with average diameter of 6 nm were synthesized by using oleylamine as ligand and solvent. The insulating oleylamine ligands form barriers around the CdS CQDs to decrease carrier mobility. In order to remove the ligands and improve the photoelectrical properties of the closed-packed film, ethanedithiol, mercaptopropionic acid and cetyltrimethylammonium bromide (CTAB) were applied for solid state ligand exchange. CTAB treated film had the fastest 3 dB bandwidth of 144.7 Hz and yielded the highest detectivity of 1.37 × 10⁸ Jones. The excellent properties of ligand passivation have important application in nanocrystals based electronic and optoelectronic devices.     

High Phase Purity of Large‐Sized 1T′‐MoS2 Monolayers with 2D Superconductivity

The development of transition metal dichalcogenides has greatly accelerated research in the 2D realm, especially for layered MoS₂. Crucially, the metallic MoS₂ monolayer is an ideal platform in which novel topological electronic states can emerge and also exhibits excellent energy conversion and storage properties. However, as its intrinsic metallic phase, little is known about the nature of 2D 1T′‐MoS₂, probably because of limited phase uniformity (<80%) and lateral size (usually <1 µm) in produced materials. Herein, solution processing to realize high phase‐purity 1T′‐MoS₂ monolayers with large lateral size is demonstrated. Direct chemical exfoliation of millimeter‐sized 1T′ crystal is introduced to successfully produce a high‐yield of 1T′‐MoS₂ monolayers with over 97% phase purity and unprecedentedly large size up to tens of micrometers. Furthermore, the large‐sized and high‐quality 1T′‐MoS₂ nanosheets exhibit clear intrinsic superconductivity among all thicknesses down to monolayer, accompanied by a slow drop of transition temperature from 6.1 to 3.0 K. Prominently, unconventional superconducting behavior with upper critical field far beyond the Pauli limit is observed in the centrosymmetric 1T′‐MoS₂ structure. The results open up an ideal approach to explore the properties of 2D metastable polymorphic materials.     

高流动性星型尼龙12的合成与表征

在均苯三甲酸的存在下,进行十二内酰胺的水解聚合,合成了四种不同臂长的三臂星型尼龙12,对产物的分子量进行了测定,并对其力学性能和流变行为进行了研究。结果表明,星型尼龙12的分子量随着均苯三甲酸含量的提高而降低,与相应分子量的线型尼龙12相比,星型尼龙12的拉伸强度和弯曲强度基本保持,冲击强度保持率在80%以上,断裂伸长...     

Comparison of the effects of Mg–6Zn and titanium on intestinal tract in vivo

To evaluate the ability of Mg–6Zn to replace titanium nails in the reconstruction of the intestinal tract in general surgery, we compared the Mg–6Zn and titanium implants with respect to their effects on rat’s intestinal tract by biochemical, radiological, pathological and immunohistochemical methods. The results indicated that Mg–6Zn implants started to degrade at the third week and disintegrate at the fourth week. No bubbles appeared, which may be associated with intestinal absorption of the Mg–6Zn implants. Pathological analyses (containing liver, kidney and cecum tissues) and biochemical measurements, including serum magnesium, creatinine, blood urea nitrogen, glutamic–pyruvic–transaminase and glutamic–oxaloacetic–transaminase proved that degradation of Mg–6Zn did not harm the important organs, which is an improvement over titanium implants. Immunohistochemical results showed that Mg–6Zn could enhance the expression of transforming growth factor-β₁. Mg–6Zn reduced the expression of tumor necrosis factor at different stages. In general, our study demonstrates that the Mg–6Zn alloy had good biocompatibility in vivo and performed better than titanium at promoting healing and reducing inflammation. It may be a promising candidate for stapler pins in intestinal reconstruction.     

沙柳/聚乙烯醇新型水凝胶复合膜的制备及性能研究

采用湿法纺丝合成新型沙柳木粉(SPP)/聚乙烯醇(PVA)水凝胶复合膜(SPPM)。研究凝固浴时间、硫酸浓度对SPPM吸附Hg²⁺吸附量与力学性能的影响。采用扫描电镜(SEM)、比表面积和平均孔径、红外光谱(FT-IR)和X射线衍射(XRD)等手段分析SPPM的结构和吸附机理;采用热重(TG)对SPPM的热性能进行分析。结果表明:凝固浴时间为1h, H₂SO₄浓度为7%时最佳,吸附量为421mg/g。SPPM具有较好的孔道结构,吸附性能良好且可重复利用5次以上,并具有较大的比表面积以及良好的热稳定性。SPPM的Hg²⁺吸附过程符合伪二级动力学模型和Freundlich等温线模型。     

NMOB与花生酸的组装多层膜及其非线性光学性质

利用与花生酸交替的方法，制备了2－硝基－5（N－甲基－N－十八烷基）氨基苯甲酸（NMOB）非中心对称多层膜，研究了它的非线性光学性质，结果表明，该多层膜的二次谐波强度与NMOB层数平方基本成正比。X－射线小角衍射测定结果再次表明，多层膜的排列相当有序，NMOB单层膜厚度为2．76nm.NMOB有良好的二阶非线性光学性质和出色的成膜性质，是一种很好的非线光学LB膜材料，可望用于制作光波导。     

Effects of nanocrystalline ferrite particles on densification and magnetic properties of the NiCuZn ferrites

Effects of nanocrystalline ferrite particles addition on densification behavior and magnetic properties of the NiCuZn ferrites were investigated. It was confirmed that nanocrystalline ferrite particles enhanced densification of the samples obviously. The reason was attributed to the nanocrystalline particles, which spread around the micron-sized ferrite particles, increased contacting area and inter-diffusion of the particles. When the amount of nanocrystalline particles addition reached to 30 wt%, the samples obtained an approximate densification behavior as the 1.5 wt% Bi₂O₃ added samples. Due to relatively bigger grain size, higher sintering density and no different chemical composition sintering aids added, the sample with 30wt% nanocrystalline ferrite particles got the highest permeability and relatively high Q-factor when sintered at 900.     

Collaborative Design of Hollow Nanocubes,In Situ Cross‐Linked Binder,and Amorphous Void@SiOx@C as a Three‐Pronged Strategy for Ultrastable Lithium Storage

Although silicon‐based materials are ideal candidate anodes for high energy density lithium‐ion batteries, the large volumetric expansion seriously damages the integrity of the electrodes and impedes commercial processes. Reasonable electrode design based on adjustable structures of silicon and strong binders prepared by a facile method is still a great challenge. Herein, a three‐pronged collaborative strategy via hollow nanocubes, amorphous Void@SiO_x@C, and in situ cross‐linked polyacrylic acid and d ‐sorbitol 3D network binder (c‐PAA‐DS) is adopted to maintain structural/electrode integrality and stability. The all‐integrated c‐PAA‐DS/Void@SiO_x@C electrode delivers excellent mechanical property, which is attributed to ductility of the c‐PAA‐DS binder and high adhesion energy between Void@SiO_x@C and c‐PAA‐DS calculated by density functional theory. Benefiting from the synergistic effect of accommodation of the hollow structure, protection of outer carbon shell, amorphous Void@SiO_x@C, and strong adhesive c‐PAA‐DS binder, c‐PAA‐DS/Void@SiO_x@C shows excellent electrochemical performance. Long cycling stability with a reversible capacity of 696 mAh g^?1 is obtained, as well as tiny capacity decay after 500 cycles at 0.5 A g^?1 and high‐rate performance. The prelithiated Void@SiO_x@C||LiNi_0.5Co_0.2Mn_0.3O₂ (NCM523) full cell is also assembled and shows a reversible capacity of 157 mAh g^?1 at 0.5 C, delivering an excellent capacity retention of 94% after 160 cycles.