Bionic Spider Web Flexible Strain Sensor Based on CF‑L and Machine Learning

At present, the preparation of laser-induced graphene (LIG) has become an important technology in sensor manufacturing. In the conventional preparation process, the CO2 laser is widely used; however, its experimental period is long and its efficiency needs to be improved. We propose an innovative strategy to improve the experimental efficiency. We use the machine learning method to accurately predict the preparation parameters of LIG, so as to optimize the experimental process. Different structures can lead to different sensor performances. The structure constructed by the CO2 laser is rough and has a large size, which can affect the performance of the sensor. Therefore, we propose for the first time an innovative method for intramembrane structure construction that combines the advantages of the CO2 laser and fiber laser (CF-L). With this CF-L method, we have successfully prepared a biomimetic, flexible strain sensor. This sensor not only maintains a high degree of sensitivity, but also has a more refined and optimized structure. The manufacturing process of the whole sensor is simple, economical, and durable and can be prepared in large quantities and can be used to detect the extension and bending of human joints

Synthesis of Carbon Nanofibers Film from Coal Liquefaction Residues: Effect of HNO₃ Pretreatment

Preasphaltene derived from coal liquefaction residues (CLRPA) has a high carbon content and is easily graphitized, making it an excellent precursor for obtaining carbon nanofibers. In this work, carbon nanofibers film (CLRPACF) was obtained by electrospinning CLRPA and polyacrylonitrile (PAN) composites, HNO3 pretreatment, air stabilization, and carbonization. During the process, HNO3 pretreatment is crucial in maintaining morphology and regulating physicochemical properties. The effect of HNO3 pretreatment on as-spun and stabilized nanofibers was investigated. The characteristics of changes occurring at various temperatures and reaction times were evaluated via Fourier transform infrared and X-ray photoelectron spectroscopy. The results show that HNO3 pretreatment introduces −NOx groups into as-spun nanofibers, thereby promoting polymerization reactions at low temperatures. The cyclization cross-linking reaction of PAN molecules and oxidative polymerization reactions of CLRPA, along with the conversion of oxygen-containing functional groups from hydroxyl oxygen to carbonyl oxygen, mainly occur during the stabilization process. Our findings show that HNO3 pretreatment can improve the oxidative stability of low softening point pitch-based carbon nanofibers

<b>Supplemental Material - Re-examining Jane Jacobs’ doctrine using new urban data in Hong Kong</b>

Supplemental Material for Re-examining Jane Jacobs’ doctrine using new urban data in Hong Kong by Jianxiang Huang, Yuming Cui, Lishuai Li, Mengdi Guo, Hung Chak Ho, Yi Lu, Chris Webster in Environment and Planning B: Urban Analytics and City Science</p

Preparation and Characterization of Thiourea-Containing Silica Gel Hybrid Materials for Hg(II) Adsorption

Thiourea-containing silica gel hydrid materials (HO-SG-GPTS-TS and HE-SG-GPTS- TS) were prepared by homogeneous and heterogeneous methods for Hg­(II) adsorption. Structures of HO-SG-GPTS-TS and HE-SG-GPTS-TS were confirmed by FTIR, ¹³C NMR, ²⁹Si NMR, SEM, TGA, and porous structure analysis. Homogeneous preparation is demonstrated to be more efficient than heterogeneous one to load more functional groups and therefore shows better adsorption property. The optimal adsorption pH was 6 for the adsorbent. Kinetics of adsorption was well fitted by a pseudo-second-order model and dominated by film diffusion process. The isotherm adsorption was best described by Langmuir isotherm model and processed by chemical mechanism. Thermodynamics implied the adsorption was spontaneous and endothermic. Selective adsorption indicated HO-SG-GPTS-TS exhibited excellent selectivity for Hg­(II) in the binary system contains Pb­(II), Ni­(II), and Co­(II)

Synthesis of δ-Carbolines via a Pd-Catalyzed Sequential Reaction from 2-Iodoanilines and <i>N</i>-Tosyl-enynamines

A facile Pd-catalyzed sequential reaction has been developed for the synthesis of δ-carbolines from 2-iodoanilines and N-tosyl-enynamines. This protocol involves Larock heteroannulation/elimination/electrocyclization/oxidative aromatization cascade sequences and allows access to multisubstituted δ-carbolines in moderate to good yields

Acid-Resistant Catalysis without Use of Noble Metals: Carbon Nitride with Underlying Nickel

A nanocomposite able to function as a hydrogenation catalyst under strongly acidic conditions without the presence of noble metals is synthesized and thoroughly studied. This specially designed catalyst possesses a unique structure composed of carbon nitride (CN) with underlying nickel, in which the nickel endows the CN with new active sites for hydrogen adsorption and activation while it itself is physically isolated from the reactive environment and protected from poisoning or loss. The CN is inert for hydrogenation without the help of nickel. The catalyst shows good performance for hydrogenation of nitro compounds under strong acidic conditions, including the one-step hydrogenation of nitrobenzene in 1.5 M H₂SO₄ to produce <i>p</i>-amoniophenol, for which the acid in the reaction system has restricted the catalyst only to noble metals in previous studies. Further characterization has demonstrated that the nickel in the catalyst is in an electron-deficient state because some of its electron has been donated to CN (HRTEM, PES); thus, the hydrogen can be directly adsorbed and activated by the CN (HD exchange, in situ IR and NMR). With this structure, the active nickel is protected by inert CN from the corrosion of acid, and the inert CN is activated by the nickel for catalytic hydrogenation. The assembly of them gives a new catalyst that is effective and stable for hydrogenation even under a strongly acidic environment

Synthesis of δ-Carbolines via a Pd-Catalyzed Sequential Reaction from 2-Iodoanilines and <i>N</i>-Tosyl-enynamines

A facile Pd-catalyzed sequential reaction has been developed for the synthesis of δ-carbolines from 2-iodoanilines and <i>N</i>-tosyl-enynamines. This protocol involves Larock heteroannulation/elimination/electrocyclization/oxidative aromatization cascade sequences and allows access to multisubstituted δ-carbolines in moderate to good yields

Synthesis of 3‑Alkyl- or 3‑Allenyl-2-amidobenzofurans via Electrophilic Cyclization of <i>o</i>‑Anisole-Substituted Ynamides with Carbocations

A facile carbocation-induced electrophilic cyclization reaction has been developed for the synthesis of 3-alkyl- or 3-allenyl-2-amidobenzofurans from o-anisole-substituted ynamides and diarylmethanol or 1,1-diarylprop-2-yn-1-ol