The chemical recycling of plastic waste to value-added chemicals, with the advantages of reducing pollution and lower carbon emissions, shows great potential in the circular economy. However, traditional treatment methods have limitations such as high energy consumption, the need for toxic reagents, limited substrate scope, and low efficiency. Here, we present an efficient and sustainable flavin-scandium-thiourea upcycling method employing an easily available, green, and nontoxic flavin as a catalyst. This method enables the conversion of polystyrene with M w as high as 1,700,000 g/mol and already-used plastics into benzoic acid with yields of up to 68%. Operating under mild conditions with visible light and ambient air, the protocol features a green catalyst, high efficiency, and broad substrate scope for the selective upcycling of PS from real-life plastic waste, aligning with green chemistry principles.

Cyanide (CN-), a highly toxic substance, is prevalent across industrial, agricultural, and natural environments, posing a grave threat to human health and ecosystems. Numerous fluorescent probes for cyanide detection have been developed based on mechanisms such as photoinduced electron transfer (PET) and intramolecular charge transfer (ICT). In this study, a theoretical approach was employed to investigate the sensing mechanism, photophysical properties, and reaction pathways of the TTB fluorescent probe in tetrahydrofuran (THF) solvent. This approach integrates the polarizable continuum model (PCM), time-dependent density functional theory (TD-DFT), and the thermal vibration correlation function formalism (TVCF) to provide a comprehensive understanding of the probe's properties and behaviors. The photophysical and chemical properties of the fluorescent probe TTB and its cyanide adduct, TTB-CN, were systematically investigated. The results indicate that the TTB probe itself exhibits negligible fluorescence, whereas the product formed upon binding with cyanide demonstrates significant fluorescence emission. This difference is attributed to the substantially lower predicted radiative decay rate (kr) of TTB compared to that of TTB-CN. Furthermore, the presence of a fluorine atom in TTB enhances the intersystem crossing rate (kisc) by a factor of 7 relative to TTB-CN. Consequently, the calculated fluorescence quantum yield of TTB is only 0.042%, while that of TTB-CN exceeds 18.14%. These findings provide a scientific basis for the application of TTB as a fluorescent probe. Investigations into the reaction mechanism demonstrate that this reaction proceeds as a nucleophilic reaction featuring a relatively low energy barrier. Additionally, our calculations reveal that both TTB and TTB-CN exhibit two-photon absorption properties, suggesting their potential for two-photon-based detection in biological systems.

Formaldehyde (FA), a significant signal molecule in biological systems, is considered as many physiological processes and pathological diseases. Up to now, a number of fluorescent probes, crafted from naphthalene amide-hydrazine scaffolds, have been designed and synthesized for the purpose of FA detection. These probes are based on the principles of photoinduced electron transfer (PET) and twisted intramolecular charge transfer (TICT). In this article, we employed a theoretical method to undertake a comparative analysis of the sensing mechanisms, photophysical characteristics, and reaction mechanism of Na-FA (6-hydrazineyl-2-propyl-1H-benzo[de]isoquinoline-1,3(2H)-dione) probe in aqueous environments. This method integrates the polarizable continuum model (PCM), time-dependent density functional theory (TD-DFT), and the thermal vibration correlation function (TVCF) formalism to provide a comprehensive understanding of the probe's properties and behaviors. Our results indicated that the weak emission of Na-FA owes to the TICT and nonradiative dissipation; conversely, PET has little effect on it. In contrast, the bright emission, exhibited by the reaction product NZ (6-(2-methylenehydrazineyl)-2-propyl-1H-benzo[de]isoquinoline-1,3(2H)-dione) of probe molecule Na-FA and FA, can be attributed to the more rapid radiative transitions and relatively slower nonradiative transitions, and there is no PET involved. In addition, we found NZ possesses a greater two-photon absorption (TPA) cross section in the near infrared region compared with that of Na-FA molecule, which determines its application in TPA detection in organisms. The reaction mechanism of Na-FA and FA producing NZ has been investigated as well; according to the potential energy profile, we discovered that path B corresponds to a lower activation energy with the aid of ion participation; therefore, path B is a more favorable reaction pathway. At last, we predicted the one-photon and two-photon properties of thiol-substituted naphthalimide, and the calculated results indicated that this compound has excellent potential as a two-photon fluorescent probe.

The photophysical and photochemical properties of the sulfonyl azide-based fluorescent probe DNS-Az and its reduction product DNS by hydrogen sulfide (H2S) have been investigated theoretically. The calculated results indicated the first excited states of DNS-Az was dark state (oscillator strength less than 0.03) and DNS was bright state (oscillator strength more than 0.1), which determined the predicted radiative rate kr of DNS-Az was much smaller than that of DNS, meanwhile, due to more larger reorganization energy of DNS-Az, its predicted internal conversion rate kic was four times larger than that of DNS; moreover, owing to the effect of heavy atom from sulfur atom in DNS-Az, its predicted intersystem crossing rate kisc was seven times larger than that of DNS, thus the calculated fluorescence quantum yield of DNS-Az was only 2.16% and that of DNS was more than 77.2%, the above factors is the basis for DNS-Az molecule to function as a fluorescent probe. Regarding both DNS-Az and DNS molecules, their maximum Huang-Rhys factors, which are less than unity, signify the reliability of 0-0 transitions between their S0 and S1 electronic states. In addition, for DNS, our simulated emission peak of the 0-0 transition is 515 nm, a value that exhibits enhanced accuracy and coherence when compared to the experimental datum of 528 nm. The reaction mechanism of DNS-Az generating DNS by H2S has been investigated too, according to the potential energy profile, we found that the fluorescent probe firstly protonated, then this organic ion broke down into DNS with the aid of a proton.

We have designed and synthesized a novel fluorescent probe BMH for detection of hypochlorous acid (HClO), which can increase dramatically the fluorescence intensity and had ultrafast response, a low detection limit and a wide pH range of application. In this paper, we further studied its fluorescence quantum yield and photoluminescence mechanism theoretically. The calculated results indicated the first excited states of BMH and BM (it was the oxidized product by HClO) were bright states with large oscillator strengths, however, due to more larger reorganization energy of BMH, the predicted internal conversion rate kIC of BMH was four orders of magnitude larger than that of BM; moreover, owing to the effect of heavy atom from sulfur atom in BMH, the predicted intersystem crossing rate kisc of BMH was five orders of magnitude larger than that of BM; meanwhile there was no significant difference found between both the predicted radiative rates kr, thus the calculated fluorescence quantum yield of BMH was nearly zero and that of BM was more than 90%, the data showed the BMH had no fluorescence but its oxidated produce BM possessed strong fluorescence. In addition, the reaction mechanism of BMH transforming into BM has been investigated too, according to the potential energy profile, we found that the course of BMH converting into BM consisted of three elementary reactions. The research results revealed the solvent effect can decreased the activation energy, which was more favorable for these elementary reactions.

Gansu has a long history and rich cultural heritage. During the Shang and Zhou Dynasties, many tribes appeared in Gansu. With the development of productivity, these tribes rose rapidly and developed from the central region of China to the coastal areas. Many bronzes of the Shang and Zhou Dynasties have been unearthed in Gansu Province. Previous scholars have conducted a lot of research on them, but most of them are only aimed at bronze ritual vessels, and there are few inductive studies on bronze weapons of the Shang and Zhou Dynasties and related research literature. Based on archaeological excavation reports and a variety of data on bronze weapons, this paper briefly summarizes the discovery, archaeological types and inscriptions of bronze weapons unearthed in the Shang and Zhou Dynasties in Gansu, and provides some reference for future research on bronze weapons.

In this work, feather keratin was extracted from the waste feather of chicken via alkyd pretreatment and reduction method, the extraction rate is above 85%. The molecular weight and aggregation morphology of feather keratin in an aqueous environment were characterized by 18-angle laser light scattering gel permeation chromatography and field emission transmission electron microscopy. The relationship between the structure and properties of feather keratin is discussed. The 1-(3-dimethylaminopropyl) -3-ethylcarbondiimide hydrochloride and N-hydroxysuccinimide were used as activation system and cross-linkage. The gallic acid was used as modification reagent and was bonded to feather keratin chains; meanwhile, feather keratin chains were cross-linked through covalent bonds obtained the novel adsorbent (named as GA-FK gel). The GA-FK gel was investigated by IR, SEM, TGA, XRD, and BET methods. The results indicated that GA molecules successfully bonded to feather keratin chains and cross-linked between feather keratin chains. The GA-FK gel was found to have a three-dimensional network structure with abundant mesopores. Its pore size range is 1.8~90 nm; average pore size is 19.6 nm. Its specific surface area is 7.17 m2·g−1. In addition, GA-FK gel was applied to remove Fe(III) in water. The maximum adsorption capacity was 319.0 mg·g−1. The adsorption process of GA-FK gel to Fe(III) presents a typical two-stage pattern accompanied with swelling. The adsorption kinetics of GA-FK gel to Fe(III) follows the quasi-second-order model, the adsorption isotherm follows the Freundlich model. Therefore, the adsorption mechanism is non-specific adsorption.

The process of stable adsorption of CO2 molecules on 1 × 1 × 1 and 2 × 2 × 1 CaO(100) surfaces were studied using a periodic slab model by PW91 of generalized gradient approximation ( GGA) within the framework of density functional theory. The results indicated that the Osurf atoms are the most stable adsorbed sites for CO2 on the CaO(100) surfaces,and the stable adsorbed bonds C -Osurf were obtained with adsorption energies of 0. 858 eV. The valence electrons configuration of C and Osurf atoms were changed from 2s0. 892p2. 47 and 2s1. 842p4. 99 to 2s0. 682p2. 33 and 2s1. 902p5. 17 during the adsorption system before and after adsorption, and that, the O2s atoms of CO2 molecules and Casub4s atoms of surfaces layer have the interactions. It was found that the repulsion energies is 1. 76 eV when the four CO2 molecules adsorbed on the 2 × 2 × 1 CaO(100) super cell surfaces. It indicated that the effects of that repulsive interaction between multiple CO2 molecules adsorbed on the same surfaces are not conducive to the adsorption of CO2 molecules.

The graft copolymerization of 5 vinyl monomers and Pullulan were carried out using Ce(NH4)2(NO3)2 as initiation system,sodium dodecyl benzene sulfate as emulsifier in inverse emulsion system.The evidence and characterization of Pullulan copolymers were researched by means of FTIR spectroscopy,scanning electron microscopy(SEM) and X-ray diffsaction analysis.The photochromism of 5 graft copolymer of Pullulan with Azobenzene were investigated in solutions by UV-Vis spectroscopy.

The CdS quantum dots sensitized TiO2 nanotubes were prepared by sequential chemical bath deposition (S-CBD) method and characterized by FE-SEM and UV-vis spectroscopy. And they were used to degrade the dimethyl phthalate (DMP) in aqueous under sunlight irradiation. The results show that these photo-catalysts have the highest performance, while the initial concentration of dimethyl phthalate in aqueous solution is 10 mg / L, the degradation rates reaches above 80% in the optimum condition which is the CdS deposited 20 cycles, catalyst dosage ~3cm2, and the sunlight irradiating 180 minutes.

用密度泛函理论B3LYP方法选取6-31G(d)基组,对半乳糖醛酸单体和二聚体以及它们与原硅酸分子形成的复合物进行了量子化学计算研究.结合能采用基组重叠误差法计算,从键长、键角、自然键轨道(NBO)、电荷转移等方面对计算结果进行了分析.结果表明:与半乳糖醛酸单体相比,半乳糖醛酸二聚体与原硅酸分子间的作用力较强,絮凝效果明显.

The volatile oil in the flowers of Elaeagnus lanceolata Warb.apud Diels was extracted by steam distillation with an oil yield of 0.53%and analyzed for chemical composition by GC-MS.Under optimum conditions,31 peaks were separated and 26 of them(83.9%) were identified,mainly including octyl 4-methoxycinnamate,pelargonic acid,linoleic acid,palmitic acid,Germacrene D and hydrocarbons.The volatile oil had potent inhibitory effects on the growth of E.coli, St.aureus B,subtilis and P.aeruginosa.

The high density and well ordered TiO2 nanotube array material was successfully prepared with anodic oxidation method.It was could be application in photocatalytic degradation aniline organic wastewater analog under 254 nm and 365 nm UV irradiation.The results exhibited that the the rate of degradation of aniline reached 99% under the concentration of aniline was 0.33 mmol/L,pH=7,intensity of UV irradiation was 254 nm and reaction time was 120 min.The factors that influence the rate of degradation were also investigated.It is be found the reaction time goes on,higher energy of UV irradiation and add air can increase catalytic activity.Furthermore,Fe3+ was could effectively increased the rate of photocatalytic degradation.

The compound WO3/TiO2 nanostructures were prepared by the template technique and characterized by FE-SEM and UV-vis DRS. And they were used to degrade the dimethyl phthalate (DMP) under visible light irradiation. The effects of the initial concentration of DMP and dissolved oxygen (DO) were investigated. The results show that degradation rates reaches 59% in the optimum condition which is ​​the catalyst dosage ~3cm2, the DO is 19.2 mg/ L, xenon lamp irradiating 300 minutes and the initial concentration of dimethyl phthalate in aqueous solution is 10 mg / L.

The flower essential oil in Elaeagnus lanceolata Warb. apud Diels flowers is extracted by water-steaming method. The extraction rate is 0.53%. The chemical compositions of the essential oil have been identified with the optimum separating and analyzing conditions by means of the GC-MS. The result shows 31 compounds are separated. The represention rate of total essential oil is 83.9％. The major chemical compositions of essential oil in Elaeagnus lanceolata Warb. apud Diels are octyl 4-methoxycinnamate，pelargonic acid , linoleic acid , palmitic acid , Germacrene D，hydrocarbon etc.

In this paper,the TiO2 nanotube arrays were successfully applied to photocatalytic degradation aniline.The factors that influence photocatalytic degradation aniline were also investigated.The results showed that the optimal reaction condition is UV wavelength irradiation of 254 nm,reaction time of 120 min and pH of 9,under which the ratio of degradation of aniline reached 87%.Furthermore,the TiO2 nanotube arrays' photocatalytic degradation activity was improved validly when Fe3+,Cu2+ and H2O2 oxides were added into the reaction system,and the degradation rate was improved by 42%,31% and 19%.Possible mechanisms for photocatalytic degradation aniline with TiO2 nanotube were proposed.

The chain polymeric Salen Schiff base metal complexes PLSBM(M:CoⅡ,MnⅡ,ZnⅡ,CuⅡ) had been prepared with terephthaloyl chloride and Salen Schiff base complexes units by interfacial polycondensation.The structure of as-prepared complexes was characterized with element analysis,FT-IR,SEM,ICP-AES and XPS.The PLSBM exhibited the irregular chain structure.The binding energy of metal ions increased 0.5~2.1eV when the stable complexes were formed.

The conservation of weathered historic sandstone with apatite was studied.Based on the growth mechanism of bone,calcium and phosphorus were introduced into weathered sandstone and then mineralized at room temperature.The conservation efficiency was investigated by scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDX),transmission electron microscopy(TEM),selected area electron diffraction(SAED),X-ray diffraction(XRD),and compressive strength,capillary water uptake,water vapor permeability and weather resistance tests.The SEM,EDX,TEM,SAED and XRD results showed that the produced hydroxyapatite could reunite the weathered stone blocks and provide sufficient reinforcement to hold them together.The results of the various tests indicated that the compressive strength and weather resistance of the treated samples was improved significantly.In addition,because of the porous nature of apatite,the water vapor permeability of the treated stone was not affected and its breathability was maintained.

A kind of novel interface self-motion in an oil/water system was studied and several self-motion patterns were observed, such as irregular motion, teeterboard-like motion and wave-like motion. Kinetic parameters, such as duration time and angular velocity, were studied and it was found that the self-motion behaviour of oil/water system was closely related to the boundary conditions, for example, concentration of reactants and the relative amount of reactants. In the proposed system, the oil phase was a solution containing nitrobenzene, picric acid and ethanol, and the aqueous phase was a solution of cetyl pyridinium bromide. A possible mechanism of the self-motion was approached.

It was oxidation of cyclohexene with molecular oxygen in presence of metal coordination compounds.The results showed that the main active reaction center appeared on the C=C bond and allylic carbon of cyclohexene.The mechanism of catalyzed oxidation cyclohexene with molecular oxygen evidenced that the main reaction was free radical chain process.Four main products were 2-cyclohexen1-yl hydroperoxide(Ⅰ),2-cyclohexen-1-one(Ⅱ),2-cyclohexen-1-ol(Ⅲ) and cyclohexhene oxide(Ⅳ).When reaction time was prolonged,the decompose reaction of Ⅱ,Ⅲ and 2-cyclohexen-1-oxide readial β bond scission brought forth,amount of oxidation derivative products were come into being.Possible mechanisms for catalytic oxidation of cyclohexene with molecular oxygen were review,as well as a persperctive of the development in the paper.