Copper is a trace element in mammalian nutrition, and it is essential to daily intake of 1.5-2.0 mg of copper. However, excessive intake of copper can cause toxicity to the human body, so it is very important to quantitative analysis copper levels of serum and urine in early diagnosis of certain diseases. In this paper, based on the strong fluorescence quenching effect of Cu²⁺ on nitrogen-sulfur-doped graphene quantum dots, a rapid, highly sensitive and reliable method was established, the limit of determination is 2.708 nmol/L. Variable temperature experiments and thermodynamic calculations were explored to discuss the mechanism of fluorescence quenching, results show that the quenching process is static quenching process.

The geometries and spectroscopic properties of [Ir(ppy)₂(ppz)]⁺(1), [Ir(ppy)₂(ppz)]⁺(2), [Ir(ppy)₂(ppz)]⁺ (3) (3 and 2 are different in the connection position of benzene ring) [ppy=phenylpyridine, ppz=(2-pyridyl)pyrazole, ph=phenyl] complexes were studied theoretically. B3LYP functional and single excited configuration interaction (CIS) methods were used to optimize the S₀ and T₁ structures. The absorption and emission spectra of the complexes in CH2Cl2 solution were calculated by time dependent density functional theory (TD-DFT) and polarized continuum model (PCM). The results show that Ir-N3 and Ir-N4 obtained by the ground state optimization are in good agreement with the corresponding experimental values. The lowest energy absorption of complexes 1-3 is 447.91 nm, 456.52 nm and 516.90 nm, and the phosphorescence emission is 512.02 nm, 501.14 nm and 562.29 nm, respectively. The highest occupied molecule orbit (HOMO) of complexes 1-3 is mainly occupied by Ir and ppy, and the lowest unoccupied orbit (LUMO) is occupied by ppz ligands π* orbit. Therefore, this transition is referred to as the metal to ppz ligand and ppy ligand to ppz ligand charge transfer (MLCT/LLCT) transition. Moreover, the absorption and emission of these complexes are greatly influenced by ppy and ppz ligands.

In large-scale concrete projects, the polycarboxylate superplasticizer is severely adsorbed by a small amount of soil in the raw material sand and gravel, which causes its performance to decline. Therefore, modification research aimed at improving the performance and mud resistance of polycarboxylate superplasticizer is a hot spot in the field of polycarboxylate superplasticizer. The synthesis of active macromonomer is an important part of the modification of polycarboxylate superplasticizer. This article introduces the common mechanisms in polymer polymerization and the catalysts used in different mechanisms and their research progress, and summarizes the advantages and disadvantages of different polymerization mechanisms in the synthesis of active macromonomer of polycarboxylate water-reducing agents, prospects for the research of catalysts used in different polymerization mechanisms.

In this paper, the water quality characteristics of the produced water from Nan 4-8 (weak alkali) and Sanyuan-6 (strong alkali) of Daqing Oilfield are measured. Combining the particle size distribution and morphological characteristics of the produced water, the critical micelle concentration (CMC) theory is used to discuss the stability of the oil displacement water, and the influences of oil displacement agent, temperature, pH value and inorganic salt on the CMC of the produced water are analyzed. The ASP flooding water CMC is much smaller than the flooding water raw water concentration, indicating that a bilayer is formed in ASP water system. The CMC of flooding water is relatively affected by the pH of the system, that is, the alkali in the oil displacing agent can react with the active substances in the crude oil to form organic acid salts, which have a certain hydrophilic and lipophilic activity. The polymer has the properties of a surfactant while increasing the viscosity of the flooding, and is partially hydrolyzed under the action of an alkali to form a polyelectrolyte and promote the formation of a double-electron layer.

In order to improve the adsorption performance of activated carbon, magnesium oxide modified activated carbon (MgO/GAC) was prepared by equal volume impregnation with magnesium nitrate and activated carbon, adopting high temperature roasting. The influence of temperature and adsorption time on the adsorption of low-concentration reactive red dye in wastewater was tested by the composite material. The results showed that the iodine adsorption value of MgO-GAC was 960.42mg/g with 3.5mol/L magnesium nitrate impregnation, calcination temperature 600℃, calcination time 2h. Scanning electron microscopy (SEM) photos showed that the surface of the unmodified granular activated carbon had the micropore diameter of about 3μm, and the surface of the modified MgO-GAC composite had hte uniform micropore size, with the pore size of about 6-7μm. The surface was loaded with a large number of small round particles. High-temperature roasting had a pore expansion effect on granular activated carbon, and could convert magnesium nitrate into porous magnesium oxide, which could be effectively loaded on the surface of granular activated carbon. The optimal conditions for the adsorption of Reactive Red X-3B dye with the MgO-GAC composite material were as follows: the dosage was 0.1 g, the temperature was 30℃, the pH value was 6, and the removal rate of reactive red dye reached 92.5%. The preparation method of modified activated carbon was feasible,high temperature expansion and porous magnesia increased the surface area of granular activated carbon,which improved the adsorption effect of the reactive red dye.

Copper sulfide nanomaterials are characterized by a narrow band gap. Using copper chloride, 1-octadecene and oleylamine as raw materials, copper sulfide nanocrystals are synthesized by high-temperature pyrolysis. The synthesized copper sulfide is characterized and analyzed by XRD, TEM, absorption spectroscopy, infrared spectroscopy and other means. The experimental results prove that the copper sulfide nanocrystals we synthesized are Cu_1.1S, the morphology is particle-like, and the dispersion is uniform. It is used in photocatalysis. It is found that copper sulfide has relatively high photocatalytic activity in the ultraviolet and visible regions. After irradiating with a 35W xenon lamp for 40min, we found that the degradation rate of methylene blue using copper sulfide as a catalyst can reach 97.8%.

Ce-doped LaCrO₃ samples were synthesized by mild hydrothermal method. The samples show good crystallinity. Sample morphology can be affected by the concentration of mineralizer (KOH). With the same starting chemicals ratio of La:Ce:Cr, hollow, rectangle, smooth, roughed and porous cubics could be resulted when 3, 4, 5, 6 and 7 g KOH was added in the reactive mixture. According to XPS results, Ce is mainly +4, and minor Cr²⁺ occurred in the samples. This research is important to the synthesis and application of Ce-doped LaCrO₃ materials.

Based on the principle of intramolecular charge transfer, naphthimide was selected as the fluorophore and reacted with triphenylamine through a coupling reaction to prepare a naphthalimide derivative organic optical functional small molecule material. The synthesis route is simple and the experimental operating conditions are easy to control, and the yield of target product is very high. Its optical properties were studied. Its optical properties were studied. The optical properties in different solvents mainly showed two strong absorption bands. Its fluorescence emission reached the near infrared region, and exhibited very obvious aggregation-induced emission (AIE) characteristics. The solid showed a strong orange fluorescence phenomenon.

NaY(WO₄)₂ functional material is an important inorganic functional material in tungstate system. This article reviews the preparation methods and application fields of NaY(WO₄)₂ functional materials, and introduces various synthesis of NaY(WO₄)₂ functional materials such as high temperature solid phase method, microemulsion method, hydrothermal method, sol-gel method, etc. The method, and summarized the respective characteristics. At the same time, the application and future research directions of NaY(WO₄)₂ functional materials in lighting and display, optical materials, photocatalytic materials and other emerging fields are described.

In order to solve the influence of Doppler effect on the speed and accuracy of spectrum detection in the Internet of vehicles, the spectrum sensing algorithm in the case of high-speed vehicle movement is studied. Firstly, the cognitive radio technology and the Internet of vehicles technology are introduced to construct the cognitive radio enabled vehicular ad-hoc networks, and a spectrum sensing algorithm is proposed to solve the problem of low spectrum utilization.The experimental results show that the algorithm can eliminate the Doppler shift effect, improve the performance of spectrum detection, and solve the problem of signal distortion when the vehicle is moving at high speed.

A wireless device for human physiological parameters is designed by using max31002, the device is STM32 series microcontroller as the core, through the MAX30102 model using photocapacity pulse description method (PPG) to collect the pulse wave signal of the index finger ending artery, and then the source signal digital filtering processing and scale conversion, to obtain blood oxygen and heart rate measurements, and can communicate with the mobile phone Bluetooth. By calibration comparison, the measurement range of blood oxygen saturation is 35% to 100% (the blood oxygen saturation of normal human arterial blood is 98%), the resolution is 1%, the accuracy is 70% to 100% ± 2%, less than 70% is undefined, and the pulse charge is 0 .4%, can correctly show oxygen saturation, heart rate measurement range of 0 to 150 times/minute (adult normal heart rate of 60 to 100 times/minute), the error is not more than 1%, the temperature range 0 to 50 ℃, the resolution of 0.1 ℃, the error is not more than 0.2%.

For the hyundai-hs220 six axis manipulator, the improved D-H modeling method is used to construct the robot joint coordinate system, the forward and inverse kinematics equations are analyzed and deduced, the robot model is constructed in the simulation environment based on MATLAB platform and robot toolbox, the forward and inverse kinematics equations are simulated and calculated respectively, and the correctness of the kinematics equations is verified. In the experiment of trajectory planning in joint space, the continuous and stable motion curves of each joint are obtained, which lays a theoretical foundation for the follow-up trajectory planning control.

In recent years, with the progress of science and technology, underwater detection technology has provided great convenience and security for offshore and river outdoor fishing activities. Sonar fish detector is a kind of auxiliary accessory to observe the fish condition. It is suitable for fishing enthusiasts and fishermen to fish in rivers, lakes, seas and other places. It can help users to easily judge the weather temperature, water depth, fish or fish number and depth. The research on the detection mode of sonar fish detector can provide an effective basis for improving the function of the equipment and optimizing the detection effect.

A pneumatic flexible wrist has been developed using an elongated actuator and a spherical brake. Using the method of statics experiments, the relationship between the rotation angle of the wrist end cap and the air pressure is analyzed. When the air pressure value is 0.34 MPa, the rotation angle of the wrist end cap is 41°. Using a combination of theory and experiment, the mechanical characteristics of the wrist brake are analyzed. When the air pressure value is 0.4MPa, the axial thrust of the brake airbag is 107N, and the wrist braking torque equation is obtained.

The metal Ce was doped into Bi₂O₃ Based on the electrospinning technology, and a novel linear composite catalyst with enhanced photocatalytic activity was prepared. The effect of different doping ratio on the modification of Bi₂O₃ was studied by XRD, SEM, TEM and UV vis-DRS characterization and analysis. And the home-made photocatalyst was applied to treat dye wastewater in the liquid phase, with degradation of methyl orange as the goal, the research results show that metal Ce successfully doped into the Bi₂O₃ replaced the part of the Bi lattice, the doping ratio of 0.25 possess best visible light catalytic activity, the absorption edge redshift is the largest, and the band gap width is 2.22eV, The catalytic degradation rate of MO under visible light irradiation reaches 98.81% in 90 minutes. The photodegradation process conforms to the first-order kinetic process, and the photocatalyst property is stable.The research results provide basis and support for the modification and development of Bi₂O₃, the development of new composite photocatalytic materials, and the photodegradation of organic pollutants with poor biodegradability in the water treatment field.

Small particle ZSM-5 Zeolite were synthesized by hydrothermal method with different surfactants such as SDBS, PEG and Tween. The effects of different surfactants and synthesis conditions on the synthesis of small particle ZSM-5 zeolite were studied. The physical properties of the products were characterized by means of X-ray diffraction(XRD),Scanning electron microscopy(SEM). When adding 2.5g Tween surfactant , the dispersion and particle size reached the best level.

Transition metal nitride has many excellent physical and chemical properties and abundant crystal structure. But phase pure transition metal nitrides are difficult to be synthesized, which greatly limits the exploration of its characters. Using theoretical calculations can effectively predict many physical and chemical properties of materials, and giving guidance to workers engaged in experimental synthesis. In this paper, WC-structured MoN which may possess high hardness is studied systematically by theoretical calculation. In this paper, density of states (DOS), bulk modulus, shear modulus, Mulliken population and electron localization function (ELF) of MoN were calculated using first-principles calculations. Through the calculation above, it is found that the chemical bond between molybdenum atom and nitrogen atom in MoN shows covalency, which can result in high hardness. It is worth noting that MoN shows excellent conduction characteristics, demonstrating that MoN can be used in industry as a multiple.

Based on extended negative binomial thinning operator, an integer-valued INAR(1) model is constructed by prespecifying the distribution for the innovation process. The probabilistic properties of the model are given and the parameters of the model are estimated by using the quasi likelihood estimation method, and least squares and maximum likelihood estimation methods are also considered. The validity of these estimation methods is evaluated by numerical simulation, and the application of the model is given based on the actual data. Through comparison, it is concluded that the INAR (1) based on the extended negative binomial thinning operator with the innovation process of geometric distribution is a more suitable model for the data.

A kind of compound of alkali metal potassium and carbon C4K with Pmmm symmetry was designed by inserting alkali metal potassium between two-dimensional carbon material M-graphene. The crystal structure, thermodynamic stability and electronic properties of C4K are systematically studied via the first-principles calculation of density functional theory. Results show that C4K is thermodynamically stable at high pressure, it can be synthesized in 7.5 - 24.5 GPa, and presents electronic properties of metal. This work provides some theoretical guidance for experimental synthesis of alkali metal and carbon compounds.

Ordinary differential equations, approximation for a class of neutral differential difference equations of the problem, the current popular studies have focused on a class of neutral differential difference equations in addition of constant results under the condition of less than zero, zero solution asymptotic stability of ordinary differential equations can be shown in close to a class of neutral differential difference equations, delay is sufficient and necessary conditions. However, the necessary and sufficient conditions of hysteresis are ignored under the condition that the sum of constants is equal to 0 (i.e. under the first critical condition).So the ordinary differential equations with approximation method, a class of neutral differential difference equations from constant within a class of neutral differential difference equations together, the result is less than 0 and is equal to zero, under the condition of two kinds of ordinary differential equations, respectively study the stability of zero solutions of can approach is shown in a class of neutral differential difference equations of delay sufficient and necessary conditions.