The cell structures of conductive polymer-based composite foams significantly influence their electrical properties and electromagnetic interference (EMI) shielding effectiveness (SE), necessitating a thorough understanding of how these properties improve with evolving cell structures. In this study, supercritical CO2 foaming technique was manipulated to fabricate acrylonitrile-butadiene-styrene (ABS)/carbon nanotubes (CNTs) foams. The constant-temperature mode was used to prepare unimodal foams (UF), while the bimodal foams (BF) were produced by varying-temperature mode. The foaming properties, electrical conductivity, complex permittivity, and EMI SE of ABS/CNTs foams with various cell structures are methodically investigated at identical volume expansion ratio and CNTs content. The electrical conductivity of bimodal ABS/CNTs foam with CNTs content of 20% (BF-C20) is 0.2191 S cm(-1), higher than that of unimodal ABS/CNTs foam with CNTs content of 20% (UF-C20) (0.1765 S cm(-1)) owing to the introduction of bimodal cell structures. Complex permittivity results manifest that at 8.2 GHz, the epsilon ' and epsilon '' of BF-C20 are 67.7 and 74.5, respectively, which are higher than 57.9 and 52.9 of UF-C20. Among all ABS/CNTs foams, the total EMI SE of BF-C20 attains the highest EMI shielding value, which reaches 30.2 dB. Furthermore, the absolute shielding effectiveness of BF-C20 is 188.5 dB (g cm(-2))(-1), which is 17.3% higher than that of UF-C20.

Diabetes is a chronic disease with a high incidence that requires persistent therapy with accurate drug admin-istration. We report a near-infrared light-responsive microneedle with tunable insulin supply for painless and on-demand anti-diabetes therapy. It comprises of a calcium alginate frame having near-infrared radiation-responsive polydopamine-coated poly-lactic-co-glycolic acid microspheres serving as a capsule for insulin on the frame. The microneedle initiated and stopped insulin release via a light triggered on-off mechanism. In vivo experiments revealed that our microneedle provided an appropriate dose of insulin in conformity with the daily blood glucose fluctuations to precisely maintain the blood glucose levels for a long period. These findings suggest the efficacy and safety of the developed microneedle for anti-diabetic therapy.

The Baeyer-Villiger Oxidation (BVO) of ketones and aldehydes produce lactones and formates, while aerobic carboxylation of aldehydes manufactures carboxylic acids, both having high added value. This work prepared a series of Al-containing silicates modified with organic ligands and SnO2 nanoparticles, which were then employed as catalyst in BVO and carboxylation. Characterizations revealed the morphology of the synthesized catalyst was changed from micron-sized thin sheets to smaller blocks, and then to uniform nanoparticles (size of 50 nm) having the doped SnO2 nanoparticles with a size of 29 nm. All catalysts showed high BET surface areas featuring silt-like mesopores. In determining the priority of BVO and carboxylation, an influence evaluation of the parameters showed the order to be substrate > oxidant > solvent > catalyst. Cyclic aliphatic ketones were suitable for BVO, but linear aliphatic and aromatic aldehydes for carboxylation. Coordination of (S)-binaphthol or doping of Sn into catalyst showed little influence on BVO under m-CPBA, but the Sn-doped catalyst largely increased BVO under (NH4)2S2O8 and H2O2. Calculations revealed that the catalyst containing both Al and Sn could give BVO intermediates lower energies than the Sn-beta zeolite model. The present system exhibited merits including wider substrate scope, innocuous catalytic metal, greener oxidant, as well as lower catalyst cost.

The C-3 modification of 1H-indazole has produced active pharmaceuticals for the treatment of cancer and HIV. But, so far, this transformation has seemed less available, due to the lack of efficient C-C bond formation at the less reactive C-3 position. In this work, a series of silica gel-supported PdO2 nanoparticles of 25–66 nm size were prepared by ball milling silica gel with divalent palladium precursors, and then employed as catalysts for the Suzuki–Miyaura cross-coupling of 1H-indazole derivative with phenylboronic acid. All the synthesized catalysts showed much higher cross-coupling yields than their palladium precursors, and could also be reused three times without losing high activity and selectivity in a toluene/water/ethanol mixed solvent. Although the palladium precursors showed an order of activity of PdCl2(dppf, 1,1′-bis(diphenylphosphino)ferrocene) > PdCl2(dtbpf, 1,1′-bis(di-tert-butylphosphino)ferrocene) > Pd(OAc, acetate)2, the synthesized catalysts showed an order of C1 (from Pd(OAc)2) > C3 (from PdCl2(dtbpf)) > C2 (from PdCl2(dppf)), which conformed to the orders of BET (Brunauer–Emmett–Teller) surface areas and acidities of these catalysts. Notably, the most inexpensive Pd(OAc)2 can be used as a palladium precursor for the synthesis of the best catalyst through simple ball milling. This work provides a highly active and inexpensive series of catalysts for C-3 modification of 1H-indazole, which are significant for the large-scale production of 1H-indazole-based pharmaceuticals.

The Baeyer–Villiger oxidation (BVO) of ketone and aldehyde can produce ester and formate, which both have wide applications in many areas. In this work, a series of Sn-containing silicates were prepared through the sol-gel process by using structure-directing and crystallizing agents and post-synthetic coordinated modification of binaphthol. Characterizations revealed that loading of (L)-sodium lactate as the crystallizing agent decreased the crystal size of the synthesized catalyst, and there were SnO2 nanoparticles with sizes of 17–19 nm on the catalyst. Furthermore, quite differently from the 3D mesoporous structure of classical Sn-beta zeolites, the synthesized catalysts had a silt-like mesoporous structure. In the catalysis, when cyclic aliphatic ketones were used as the substrate, only BVO-type products and corresponding ring-opening products were obtained. BVO of aliphatic aldehyde produced both an aerobic oxidation product (carboxylic acid) and a BVO-type product. The presented transformation of aromatic aldehyde (benzaldehyde) only gave an aerobic oxidation product (benzoic acid). The post-synthetic coordinating attachment of (S)-binaphthol to the Sn-containing silicate backbone worsened the BVO of aliphatic ketones but improved the BVO of aliphatic aldehyde and the aerobic oxidation of aromatic aldehyde. In addition, this work also developed two new routes for the synthesis of high-value-added 6-hydroxyhexanoic acid and cyclohexylformate under catalytic BVO conditions.

The C-3 functionalization of 1H-indazole could produce a lot of highly valuable pharmaceutical precursors, which could be used for the treatment of cancer and many other inflammatory diseases. This work was focused on the C-3 functionalization of 1H-indazole through Suzuki–Miyaura cross-coupling of 3-iodo-1H-indazole with organoboronic acids, catalyzed by various palladium catalysts immobilized over imidazolium ionic liquids, as well as catalyst recycling. A series of reaction parameters, including the substrate, catalyst, and ionic liquid, were fully investigated. It is significant to note that the yields of the present Suzuki–Miyaura cross-coupling were mainly determined by the catalyst and the solvent used, more than the chemical structure of the substrate. Furthermore, ferrocene-based divalent palladium complexes showed better catalytic outputs compared to simple palladium salts. Moreover, using two imidazolium ionic liquids, BMImX (BMIm+ = 1-n-butyl-3-methylimidazolium, X− = BF4−, PF6−) not only improved the yields of cross-coupled products, but also avoided the formation of Pd(0) black, as compared to the non-ionic liquid facilitated reactions, and simultaneously making catalyst recycling more effective. On average, BMImBF4 performed better than BMImPF6. Additionally, scientific calculations revealed that 1,1′-bis(diphenylphosphino)ferrocene-palladium(II)dichloride dichloromethane complex (PdCl2(dppf)) showed a lower energy barrier in the formation of intermediates than [1,1′-bis(di-tert-butylphosphino)ferrocene]dichloropalladium(II) (PdCl2(dtbpf)), leading to higher catalytic outputs. This work may contribute to the development of 1H-indazole-derived new pharmaceuticals.

A general overview on formation of humins, unavoidable by-products from biorefinery, and the valorization towards various products is provided. The better understanding on formation mechanism and structure of humins helps the development of relevant strategies for their valorization. Current research demonstrates the remarkable potential and widespread applications of humins including templated catalysts synthesis, fine chemicals, pharmaceutical intermediates, thermoset resins and even optoelectronic materials. The oxygen-rich nature of humins offers special functionalities in the humin-derived materials. Valorization of humins will surely attract more attention, especially in the studies on thorough understanding the humin structure and developing more sustainable chemicals and materials to enrich humin-derived products. All these efforts will contribute to the integration of biorefinery processes towards a more sustainable future.

A series of oligomeric (salen)Mn(III) complexes featuring tartrate linkers were prepared and immobilized over layered double hydroxide, and then used as catalysts for asymmetric epoxidation of unfunctionalized olefins. Comprehensive characterizations including 1H NMR, FT-IR, UV-Vis, elemental analysis, GPC, and ICP-AES were used to illustrate structures of oligomeric (salen)Mn(III) complexes, while powdered XRD, nitrogen physisorption, together with XPS studies provided further details to detect structures of heterogeneous catalysts. Interestingly, scanning electron microscopy found an interesting morphology change during modification of layered supporting material. Catalytic experiments indicated that configuration of major epoxide products was determined by salen chirality more than that of tartrate linker, but enantioselectivity (e.e. values) could be enhanced when tartrate and salen showed identical chiral configurations. Furthermore, the (R,R)-salen moieties linked with (R,R)-tartrate spacers usually offered higher enantioselectivity compared to other combinations. Lastly, Zn(II)/Al(III) layered double hydroxide played as a rigid supporting material in catalysis, showing positive chiral induction and high recycling potential in catalytic reactions.

— In order to reduce the horizontal deformation caused by the sprayer rigid frame of the plant protection machine, this paper establishes the structural dynamics model of the spray boom rigid frame based on the rigid frame structure commonly used in the plant protection machine spray boom, and transforms it into state space form. A robust controller based on state observer is designed. The boom frame with vibration deformation due to disturbance is controlled. Simulation results show that the method is effective in restraining the horizontal vibration deformation of the spray rod frame. The research results provide a method for restraining the vibration deformation of the spray rod frame structure of plant protection machine.

: Constructing the extracurricular chemistry open experiments for non-major students would help to raise the participation of students in practice instruction, thus benefiting more students. This paper has introduced the construction measures and practical experience about extracurricular chemistry open experiment for non-major students from the following aspects: the attentions in constructing the extracurricular chemistry open experiments for non-major students, the diversified construction of teaching resources and the teaching methods reform.

An injectable hydrogel was developed using mesoporous silica nanoparticles to co-deliver miR222 and aspirin, osteogenesis was enhanced by stimulating innervation.

Tumor microenvironment-sensitive mesoporous silica nanoparticles (MSNs), as up-and-coming attractive nanoplatform, have captured researchers' attention and created something of a biomedical transformation over the last few decades. This chapter will elucidate recent developments and accomplishments of MSNs in tumor-related cargo conveyance based on the recent work of our group and other groups. In particular, our group emphasizes the design and development of original organic/inorganic hybrid MSNs with on-demand designed functionalities, including aperture chem-environment, surface modifiable properties, traceable fluorescence message and phase state, and a series of stimuli-dependent delivery modalities to solid tumor. These stimuli-released nanoplatforms are capable of accomplishing active/passive tumor selectivity, multiple payload delivery, targeted payload release, real-time tumor/payload imaging, enhanced circulation in blood, and ceaseless therapy around the solid tumor.

In this work, B-N co-doped TiO2 has been synthesized by a facile fast sol-gel method, and then, a controlled magnesiothermic reduction has been developed to synthesize B-N co-doped black TiO2 under a N-2 atmosphere and at 580 degrees C followed by acid treatment. The prepared black TiO2 samples were characterized by X-ray diffraction, high resolution transmission electron microscopy, Raman spectrameter, photoluminescence emission spectra, X-ray photoelectron spectroscopy, and ultraviolet-visible diffuse reflectance spectra. It shows that the prepared samples possess a unique crystalline core-amorphous shell structure composed of disordered surface and oxygen vacancies, and exhibit enhanced photocatalytic activity in hydrogen production in the methanol-water system in the presence of Pt as a co-catalyst. Under the full solar wavelength range of light, the maximum hydrogen production rate of the B-N co-doped black TiO2 is 18.8 mmol h(-1) g(-1), which is almost 4 times higher than that of pure TiO2. (C) 2019 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Black nano-TiO2 samples with core–shell nanostructure were successfully prepared by sol–gel method combined with Mg reduction using butyl titanate as titanium source and calcining at 500°C in air atmosphere and at 400–600°C in nitrogen atmosphere. The prepared black TiO2 samples were characterized by X-ray diffraction, high resolution transmission electron microscopy, Raman spectra, photoluminescence emission spectra, N2 adsorption–desorption, and ultraviolet–visible spectroscopy. The results show that the black TiO2 exhibits a crystalline core–disordered shell structure composed of disordered surface and oxygen vacancies, and the thickness of the disordered layer is about 2–3 nm. The optical absorption properties of black nano-TiO2 samples have been remarkably enhanced in visible light region. Compared with the white TiO2, the reduced black TiO2 samples exhibit enhanced photocatalytic hydrogen production under the full solar wavelength range of light, and the sample prepared with the Mg and TiO2 ratio of 9:1 calcined at 500 °C has the maximum hydrogen production rate.

Utilizing solar energy for hydrogen evolution is a great challenge for its insufficient visible-light power conversion. In this paper, we report a facile magnesiothermic reduction of commercial TiO2 nanoparticles under Ar atmosphere and at 550 °C followed by acid treatment to synthesize reduced black TiO2 powders, which possesses a unique crystalline core–amorphous shell structure composed of disordered surface and oxygen vacancies and shows significantly improved optical absorption in the visible region. The unique core–shell structure and high absorption enable the reduced black TiO2 powders to exhibit enhanced photocatalytic activity, including splitting of water in the presence of Pt as a cocatalyst and degradation of methyl blue (MB) under visible light irradiation. Photocatalytic evaluations indicate that the oxygen vacancies play key roles in the catalytic process. The maximum hydrogen production rates are 16.1 and 163 μmol h−1 g−1 under the full solar wavelength range of light and visible light, respectively. This facile and versatile method could be potentially used for large scale production of colored TiO2 with remarkable enhancement in the visible light absorption and solar-driven hydrogen production.

翻转课堂模式有助于使课堂教学从以教师为中心向以学生为中心转变,因而受到教育界广泛关注。以邻二氮菲分光光度法测定水中微量铁为例,探索了翻转课堂教学模式在非化学化工类大学化学实验教学中的应用。依据翻转课堂教学流程研究了课前视频、课前在线检测题及课上活动的设计与实施方案,探索了将科技文献用于课前视频的教学方法。利用课上活动给学生提供自我展示的机会;利用课前视频和课前在线检测使学生的课前预习落到实处、拓宽学生视野、激发学生对化学实验的兴趣。

Mesoporous TiO2 samples with high crystallinity have been successfully synthesized by a fast sol-gel method using polyethylene glycol (PEG) and polyacrylamide (PAM) as composite templates using two-step calcining processes. The samples have been characterized by X-ray diffraction, Transmission electron microscopy, N-2 adsorption-desorption and Diffuse reflectance UV-visible absorption spectra. The results show that the sample exhibits typical mesoporous structure and high crystallinity. The effects of PEG on properties of the samples and the effect of PAM on sol-gel reaction rate have also been studied. The results show that, PAM accelerates gel rate and PEG increased the crystallinity and specific surface area of the sample. Besides, visible light photocatalytic activity of mesoporous TiO2 prepared by the fast sol-gel method is found to be improved.

Mesoporous TiO2 nanoparticles were synthesized by a fast sol–gel method using polyethylene glycol (PEG) and polyacrylamide as bi-template followed by two-step calcination under nitrogen and air atmosphere. The effects of factors such as the solvent volume, amount of water, medium pH, and amount and molecular weight of PEG on the sol–gel reaction rate were studied based on analysis of zeta potential measurements. The results showed that lower ethanol volume, lower pH, greater water volume, and higher PEG molecular weight led to faster sol–gel reaction rate with shorter gelation time, with pH and water volume being the most influential amongst these factors. The evolution during the fast sol–gel process was also investigated based on the infrared (IR) spectrum. The results indicated that the fast sol–gel process occurred due to intermolecular hydrogen bonding between hydrolysates of Ti alkoxides and the bi-template. The samples were characterized by X-ray diffraction (XRD) analysis, transmission electron microscopy (TEM), and N2 adsorption–desorption measurements, revealing high crystallinity with small crystallite size and large specific surface area.

以学生为中心的翻转课堂教学模式越来越受到教育界的关注.我们以解决传统教学模式下出现的问题为目标,在电解质溶液实验教学中进行了翻转教学设计,有课前的任务书、教学视频及检测题设计,也有课上的活动及讨论题设计.教学实践表明,翻转课堂教学模式下,学生对实验的兴趣有所提高,实验中的操作错误有所减少,实验报告出错率有所降低.参加翻转课堂教学的大多数学生表示喜欢这种新颖的教学模式.

To solve the durable antibacterial problem on special military supplies and medical textile fabric under visible light irradiation, by using tetrabutyl titanate as the Ti source, thiourea and urea as the dopant, and cotton knitted fabric as the base materials, visible light catalytic durable antibacterial cotton knitted fabric loaded with S N co?doped nano?TiO2 ( S N TiO2 ) was prepared by fast sol?gel loading in combination with low temperature heat treatment. The light absorption properties and microstructures of the prepared samples were characterized by UV?Vis spectroscopy, X?ray photoelectron spectroscopy, and scanning electron microscopy. Using Escherichia coli and Staphylococcus aureus as target object, the visible light catalytic antibacterial properties of the fabric were investigated by shake flask method. The results indicate that sulfur and nitrogen atoms are incorporated into the TiO2 lattice as substitutional and interstitial forms, which allowed light absorption band edge redshift into the visible light region and the absorption intensity was increased. The dense film of S N TiO2 is coated on the surface of the fabric samples. The antibacterial rates of all the samples for Staphylococcus aureus are superior to the AAA standard, for Escherichia coli are superior to the AA standard.