High⁃nuclearity silver clusters have attracted increasing attention not only owing to their various structures, but also due to their potential applications in many fields. The synthesis of functional high⁃nuclearity silver clusters is still a huge challenge because of the unpredictability of self⁃assembly. In this paper, we reviewed the research progress of the silver clusters constructed from AgC≡CtBu and AgStBu ligands. The synthesis strategies of these silver clusters are introduced. The formation rules of these high⁃nuclearity silver clusters were studied. The purities, morphologies and stabilities of the high⁃nuclearity silver clusters were analyzed, and their potential luminescence and electrochemical properties were researched. The application prospect and developing direction of this kind of silver cluster materials are also forecasted.
In this paper, using p⁃tert⁃butylphenol and sulfur as raw materials, the p⁃tert⁃butylthiacalix[4]arene was first synthesized under alkaline conditions, and then thiacalix[4]arene sulfonic acid was obtained by reacting with concentrated sulfuric acid. The nitration of toluene was catalyzed by thiacalix[4]arene sulfonic acid as catalyst. In the nitration of toluene, the effects of the molar ratio of toluene to nitric acid, the amount of catalyst, the reaction time and the reaction temperature on the nitration of toluene were investigated. The catalyst recovery and reuse experiments were carried out. The results showed that when n(toluene)/n(nitric acid) was 1∶4, the catalyst mass was 0.100 g, and the reaction was carried out at 80 ℃ for 6 h, the conversion of toluene was 98.0%, the ratio of o⁃para⁃nitrotoluene was 1.3, and the catalyst can be reused 4~5 times.
A SBS modified emulsified asphalt was prepared by using linear SBS latex, and the performance of emulsified asphalt was analyzed. Experiments set to test how emulsifier types, amounts of emulsifier, usage of line⁃type SBS latex and preparation technology affect the performance of modified asphalt emulsion. The morphology of modified asphalt emulsion has also been studies by using scanning electron microscope. The experiment results showed that when emulsifier was OP⁃10, usage of emulsifier was 2.0%, amount of line⁃type SBS latex was 4.0%, the shearing rate was 3 000~4 000 r/min, the shearing time was 30 min, the evaporation residue of modified asphalt emulsion was 65.5%, storage stability was 0.43% (1 d) and 2.15%(5 d), penetration was 65 mm and the softening point was 55.7 ℃, which matches the technical requirements of the road modified emulsified asphalt. SBS is also dispersed uniformly in emulsified asphalt.
Taking the heavy oil production liquid in a block of Liaohe oilfield as the research object, a compound viscosity reducer was formulated according to the current situation, and the effect of the ratio and amount of such viscosity reducer on the viscosity of heavy oil emulsion was studied. The emulsified viscosity reducing agent is composed of non⁃ionic surfactant Triton X⁃100 and zwitterionic surfactant dodecyldimethyl betaine (BS⁃12).The experimental results show that when the mass fraction of 1.6% Triton X⁃100 is added into the heavy oil alone, the viscosity reduction rate of the heavy oil can reach 75.93%; BS⁃12 with a mass fraction of 0.6% and Triton with a mass fraction of 1.6%. Triton X⁃100 is compounded by a volume ratio of 1∶1, and the viscosity reduction rate of heavy oil can be increased to 92.63%. In addition, when the complex system is added in a volume ratio of 1∶1∶1, weak alkali sodium carbonate with a mass fraction of 0.4% is added. After the aqueous solution, the viscosity reducing rate of heavy oil can be further increased to 93.14%, and the stability of the compounding system is also improved.
The oil sand water agent was optimized, and the Inner Mongolia Tumuji oil sand was taken as the experimental object. The effects of reagent concentration, reagents sand ratio, mixing time, mixing temperature to the tailings residual oil rate were investigated. According to Tumuji oil sands, the results show that under the conditions of reagent concentration of 3.50%, agent sand ratio of 0.4∶1.0, mixing time of 25 min, mixing temperature of 90 ℃, the tailings residual oil rate can reach 0.71%. The improvement reduces the water agent consumption and the residual oil rate of the tailings.
In this work, the cubic/hexagonal cadmium sulfide (c/h⁃CdS) heterojunction catalyst was successfully prepared by solid phase reaction with cadmium acetate and thioacetamide as raw materials.The synthesized catalysts were characterized by means of XRD, SEM and SPV. The activity of photocatalytic degradation of rhodamine B (RhB) was evaluated by using visible light as the light source. The effect of calcination temperature on the photocatalytic performance of CdS was investigated, and the mechanism of the degradation process was discussed. The results suggest that with the increasing of calcination temperature, c⁃CdS is gradually changing to h⁃CdS. The c/h⁃CdS phase junction formed in the phase transition shows a higher photocatalytic activity than the pure c⁃CdS and h⁃CdS, and the appropriate six⁃square phase content is more beneficial to improve the photocatalytic performance of the heterogenous sample. The results of surface photovoltage show that the formation of heterojunction can significantly improve the photoelectron⁃hole separation efficiency, thus promoting the photocatalytic performance of c/h⁃CdS phase junction. In the experiment of the sacrificial agent, the active species in the CdS photocatalytic reaction is ·O2-.
The thin strips of Fe(Co)⁃Hf⁃B⁃Cu iron⁃based strip amorphous alloys were prepared by single⁃roller⁃quenching method. The amorphous structure was determined by XRD, Mössbauer spectroscopy and transmission electron microscopy. The thermal stability of different samples was tested by differential scanning calorimetry. The results indicate the glassy structure of all the samples. Furthermore the results indicate that the thermal stability of amorphous alloys can be increased by faster cooling rate or adding pure B elements. And it can be also identified to improve the thermal stability of amorphous alloys that alloying components with the appropriate amount of Co.
The application of M⁃MOF⁃74 series in CO2 removal of natural gas was studied. The skeleton model of M⁃MOF⁃74 was established. The adsorption of pure CO2 gas and CO2/CH4 mixed gas in M⁃MOF⁃74 series adsorbent was calculated by GCMC method. The results showed that the order of adsorption of CO2 by M⁃MOF⁃74 adsorbent was Mg⁃MOF⁃74 > Ni⁃MOF⁃74 > Co⁃MOF⁃74 > Fe⁃MOF⁃74 > Cr⁃MOF⁃74 > Mn⁃MOF⁃74.When adsorbing mixed gases, the adsorption amount of CO2 by each adsorbent is consistent with that of pure CO2 adsorption, and the adsorption amount of CH4 is: Mg⁃MOF⁃74>Ni⁃MOF⁃74≈Co⁃MOF⁃74≈Fe⁃MOF⁃74≈Cr⁃MOF⁃74≈Mn⁃MOF⁃74. The law of isosteric heat of gas on M⁃MOF⁃74 is the same as that of adsorption capacity, indicating that the interaction between gas and M⁃MOF⁃74 is the main factor affecting the adsorption amount. The selectivity of each adsorbent to mixed gas: Ni⁃MOF⁃74>Co⁃MOF⁃74>Fe⁃MOF⁃74>Mn⁃MOF⁃74>Cr⁃MOF⁃74>Mg⁃MOF⁃74. Comprehensive comparison of CO2 adsorption capacity, regeneration energy consumption, selectivity coefficient and other parameters, Ni⁃MOF⁃74 is more suitable for the adsorption and separation of CO2 in natural gas.
In order to improve the accuracy of leakage volume calculation of product oil pipelines, the error analysis of the input parameters used to calculate the leakage volume of product oil pipelines is carried out, including the time lag error of the pipeline operation data, the numerical error of the pipeline inner diameter and the numerical error of the oil physical properties. Through the sensitivity analysis of the input parameters, it is found that the leakage volume is the least sensitive to flow rate. The variation rate of pipeline leakage is positively correlated with time lag rate, pressure change rate and inner diameter change rate, while it is negatively correlated with flowrate change rate. The sensitivity of pipeline leakage volume to each input parameter is different within the range of variation rate of parameters.
Three improved grey forecasting models are constructed to improve the accuracy of traditional forecasting methods. This paper took natural gas load of Beijing from 2007 to 2015 as raw data for modeling, and tested the predicting results of 2016.The traditional Grey Model and the three kind s of improved Grey Model were established to predict respectively，and the optimal model with best precision was chosen to combine with metabolism model which abandons the old data, constantly supplies new data, and repeats modeling. The optimal improved Grey Model was established to predict the annual gas load of Beijing from 2017 to 2020.The results show that the combined model can reduce the interference of the original data to the prediction system, the prediction accuracy meets the actual requirements, and the accuracy is much higher than the traditional gray model. It can truly reflect the development trend of annual natural gas load, and the prediction results are reliable and practical. It can provide reference for natural gas deployment and optimization of the pipeline network.
The most important form of energy loss in long distance gas pipelines is turbulence resistance. In order to study the rib shape on the turbulent situation through the rib of the influence law of fluid medium, this paper uses the CFD software of triangular rib and the blade shape rib between two kinds of typical ribs large eddy simulation under Reynolds number of 5 300, the wall resistance and flow field are analyzed to obtain the shape of the rib with better drag reduction effect, and to find out the reasons why the different shape ribs affect the flow field. The results show that the blade shape ribs have smaller wall resistance and smaller velocity gradient near the wall than the spaced triangular ribs. The secondary vortices generated make the flow field more stable and have better drag reduction effect.
The energy consumption evaluation indexes of fan units and pipe network system are obtained by referring to national standards and setting up a subtarget set of energy consumption evaluation,AHP analytic hierarchy process was used to analyze and compare the factors affecting energy consumption, and EXCEL software was used to deal with them. The influence degree of each factor on energy consumption was obtained, namely the weight of each factor.Using fuzzy mathematics,combining with the weight of all the factors obtained,evaluate the energy consumption for fan unit and pipe network system.Verified by examples,the system is in excellent condition,and it is consistent with the actual situation.
Based on the ANSYS platform, the numerical simulates of the temperature field in the welding process of the slurry of the slurry steam generator is carried out to obtain the distribution of the temperature field near the weld. The result of the temperature field is gradually applied to the weld to obtain the distribution of welding residual stress at the pipe head. The simulation results can play a very good role in the detection of the residual stress in the welded parts,which not only greatly saving the welding residual stress testing time, but also on the optimization of the welding process played a good reference value.
In this paper, according to the analysis of the lifting force of the suspension beam, the problem that the traditional beam⁃type or tire⁃type stabilizer is unfavorable to the deformation and instability of the hanging plate due to the increase of the tension force of the stability rope in the large⁃scale carousel of the deep well. An optimized plan for the symmetrical arrangement of the two⁃way suspension girders. For the problem that the movement of the stable device is not synchronized, the eccentricity of the disk surface is easy to cause the hanging pipe and the control is difficult, a set of hydraulic transmission control scheme that is simple, effective, and feasible is applied to different production conditions.Finally,using ANSYS analysis and the comparison of the tire stabilizer arrangement schemes with single⁃sided arrangement and double⁃sided arrangement are carried out.The result shows that two⁃way symmetrical arrangement can improve the force of the disk and beam significantly.It is considered to be worth promoting.
In this paper, the wireless communication network is established based on wireless communication equipment based on wireless network control technology. The wireless process control strategy for tank and high temperature furnace are designed, and the predictive function control (PFC⁃PID) and generalized open⁃loop response (GORC⁃PID) strategies are proposed respectively. Based on the requirement of task, the configuration of software and hardware for wireless industrial process system is achieved. On basis of this, the modelling of dynamic mathematic model of system and engineering configuration are completed. Finally, the industrial process control system based on wireless network is developed with the water tank and high temperature heating furnace of the National Local Joint Engineering Laboratory of Petrochemical Process Operation Optimization and Energy Saving Technology as the experimental device and the configuration software of Microwave Command Guidance System (MCGS) as the development and verification platform. The control results show that the developed wireless industrial process control system can control the level of tank and temperature of high temperature furnace effectively. It can avoid the drawback of wired communication at the industrial filed and has a very high industrial value.
Gas field group in remote control production during typhoon, Honeywell's general control system(including industrial production control system, emergency shutdown system, fire & gas system) was interrupted, and the offshore gas field group abandoned the platform after 30 minutes.According to troubleshooting and handling by a series of questions of Honeywell's general control system, And for communication problems between gas field control systems,updating communicational devices, revising switchboard's port configurations and so on, gasfield engineers reduces data congestion between communicational devises, improves the network environment, improves the stability of the system, as for the communicational questions. This practice has good experience promotion value and high social value.
Credit risk management is an integral part of banking business. By modifying the standard Markowitz model, the paper aims to study optimum credit portfolio with binary variable, which decides whether providing loads. The model can evaluate the cumulative risk and returns by considering the asset correlation and whether providing loads in the prospective of influencing risk indicators and profit rates. It enforces the empirical research of optimum portfolio by using the proposed model in this paper and the statistics offered by Standard & Poor's rating agency.
Manufacturing enterprises are an important source of environmental pollution. Improving managers' awareness of environmental protection and disclosing environmental information to the public are of great significance to promoting sustainable development strategy. However, enterprises are generally reluctant to disclose relevant environmental information. Therefore, based on the relevant data in the annual reports, social responsibility reports, sustainability reports and environmental reports of listed companies in Shanghai and Shenzhen Stock Exchanges, this paper analyzed the correlation between environmental information disclosure of manufacturing enterprises and their inancial performance through regression analysis. The empirical results show that the quality of enterprise environmental information report has a certain impact on the profitability, operating ability and development potential of enterprises. The higher the quality of disclosure, the better the financial benefits of enterprises.
