Comparative Molecular Field Analysis on a Set of New Herbicidal Sulfonylurea Compounds

In this paper Comparative Molecular Field Analysis (CoMFA) method was applied to study the three-dimensional quantitative structure activity relationship (3D-QSAR) on a set of new herbicidal sulfonylureas. We optimized molecular structures to improve their

Analysis of the Flow Field and Impact Force in High-Pressure Water Descaling

This study aims to improve the performances of the high-pressure water descaling technology used in steel hot rolling processes.In particular,a 2050 mm hot rolling line is considered,and the problem is investigated by means of a fluid–structure interaction(FSI)method by which the descaling effect produced by rolling coils with different section sizes is examined.Assuming a flat fan-shaped nozzle at the entrance of the R1R2 roughing mill,the outflow field characteristics and the velocity distribution curve on the strike line(at a target distance of 30–120 mm)are determined.It is found that the velocity in the center region of the water jet with different target distances is higher than that in the boundary region.As the target distance increases,the velocity of the water jet in the central region decreases.Through comparison with experimental results,it is shown that the simulation model can accurately predict the impact position of the high-pressure water on the impact plate,thereby providing a computational scheme that can be used to optimize the nozzle space layout and improve the slabs’descent effect for different rolling specifications.

Design and analysis of a high loss density motor cooling system with water cold plates

Aiming at reducing the difficulty of cooling the interior of high-density motors,this study proposed the placement of a water cold plate cooling structure between the axial laminations of the motor stator.The effect of the cooling water flow,thickness of the plate,and motor loss density on the cooling effect of the water cold plate were studied.To compare the cooling performance of water cold plate and outer spiral water jacket cooling structures,a high-speed permanent magnet motor with a high loss density was used to establish two motor models with the two cooling structures.Consequently,the cooling effects of the two models were analyzed using the finite element method under the same loss density,coolant flow,and main dimensions.The results were as follows.(1)The maximum and average temperatures of the water cold plate structure were reduced by 25.5%and 30.5%,respectively,compared to that of the outer spiral water jacket motor;(2)Compared with the outer spiral water jacket structure,the water cold plate structure can reduce the overall mass and volume of the motor.Considering a 100 kW high-speed permanent magnet motor as an example,a water cold plate cooling system was designed,and the temperature distribution is analyzed,with the result indicating that the cooling structure satisfied the cooling requirements of the high loss density motor.

Influence of slug flow on flow fields in a gas–liquid cylindrical cyclone separator:A simulation study

A simulation method for slug flow based on the VOF multiphase flow model was implemented in ANSYS?Fluent via a user-defined function(UDF)and applied to the dissipation of liquid slugs in the inlet pipe of a gas–liquid cylindrical cyclone(GLCC)separator while varying the expanding diameter ratio and angle of inclination.The dissipation of liquid slug in inlet pipe is analyzed under different expanding diameter ratios and inclination angles.In the inlet pipe,it is found that increasing expanding diameter ratio and inclination angle can reduce the liquid slug stability and enhancing the effect of gravity,which is beneficial to slug flow dissipation.In the cylinder,increasing the expanding diameter ratio can significantly reduce the liquid carrying depth of the gas phase but result in a slightly increase of the gas content in the liquid phase space.Moreover,increasing the inclination angle results in a decrease in the carrying depth of liquid in the vapor phase,but enhances gas–liquid mixing and increases the gas-carrying depth in the liquid phase.Taking into consideration the dual effects of slug dissipation in the inlet pipe and carrying capacity of gas/liquid spaces in the cylinder,the optimal expanding diameter ratio and inclination angle values can be determined.

Analysis of Electromagnetic Characteristics of a Novel Toroidal Acceleration Linear Motor

A high thrust density linear motor,which adopts a novel toroidal structure,applying to load acceleration in confined space is proposed.The basic structure of the toroidal acceleration permanent magnet synchronous linear motor(TA-PMLSM)is depicted,both with its parameters listed.The main characteristics such as air gap magnetic density and electromagnetic thrust are discussed by establishing the electromagnetic field equation in the cylindrical coordinate system.And simulation comparison between the Halbach permanent magnet array and the classical radial one is also made to get a higher density of the magnetic and electromagnetic thrust.Compared with the conventional radial permanent magnet array,results show that the amplitude of back EMF of ring motor under the action of Halbach permanent magnet array has a better sinusoidal,the magnetic density of the air gap increases by 1.3 times,the thrust density increases by 1.42 times,and the main harmonic content of the two referred physical quantity decreases significantly.

Research on the principle of space high-precision temperature control system of liquid crystals based Stokes polarimeter

The magnetic field is one of the most important parameters in solar physics,and a polarimeter is the key device to measure the solar magnetic field.Liquid crystals based Stokes polarimeter is a novel technology,and will be applied for magnetic field measurement in the first space-based solar observatory satellite developed by China,Advanced Space-based Solar Observatory.However,the liquid crystals based Stokes polarimeter in space is not a mature technology.Therefore,it is of great scientific significance to study the control method and characteristics of the device.The retardation produced by a liquid crystal variable retarder is sensitive to the temperature,and the retardation changes 0.09°per 0.10℃.The error in polarization measurement caused by this change is 0.016,which affects the accuracy of magnetic field measurement.In order to ensure the stability of its performance,this paper proposes a high-precision temperature control system for liquid crystals based Stokes polarimeter in space.In order to optimize the structure design and temperature control system,the temperature field of liquid crystals based Stokes polarimeter is analyzed by the finite element method,and the influence of light on the temperature field of the liquid crystal variable retarder is analyzed theoretically.By analyzing the principle of highprecision temperature measurement in space,a high-precision temperature measurement circuit based on integrated operational amplifier,programmable amplifier and 12 bit A/D is designed,and a high-precision space temperature control system is developed by applying the integral separation PI temperature control algorithm and PWM driving heating films.The experimental results show that the effect of temperature control is accurate and stable,whenever the liquid crystals based Stokes polarimeter is either in the air or vacuum.The temperature stability is within±0.0150℃,which demonstrates greatly improved stability for the liquid crystals based Stokes polarimeter.

Parallel-Computing Wavelet-Based FDTD Method for Modeling Nanoscale Optical Resonator

An efficient wavelet-based finite-difference time-domain(FDTD)method is implemented for analyzing nanoscale optical devices,especially optical resonator.Because of its highly linear numerical dispersion properties the high-spatial-order FDTD achieves significant reduction in the number of cells,i.e.used memory,while analyzing a high-index dielectric ring resonator working as an add/drop multiplexer.The main novelty is that the wavelet-based FDTD model is extended in a parallel computation environment to solve physical problems with large dimensions.To demonstrate the efficiency of the parallelized FDTD model,a mirrored cavity is analyzed.The analysis shows that the proposed model reduces computation time and memory cost,and the parallel computation result matches the theoretical model.

Rapid on-site identification of hazardous organic compounds at fire scenes using person-portable gas chromatography-mass spectrometry(GC-MS)—part 2:water sampling and analysis

Building and factory fires pose a great risk to human and environmental health,due to the release of hazardous by-products of combustion.These hazardous compounds can dissipate into the environment through fire water run-off,and the impact can be immediate or chronic.Current laboratory-based methods do not report hazardous compounds released from a fire scene at the time and location of the event.Reporting of results is often delayed due to the complexities and logistics of laboratory-based sampling and analysis.These delays pose a risk to the health and wellbeing of the environment and exposed community.Recent developments in person-portable instrumentation have the potential to provide rapid analysis of samples in the field.A portable gas chromatograph-mass spectrometer(GC-MS)was evaluated for the on-site analysis of water samples for the identification of hazardous organic compounds at fire scenes.The portable GC-MS was capable of detecting and identifying a range of volatile and semi-volatile organic compounds in fire water run-off,and can be used in conjunction with conventional laboratory analysis methods for a comprehensive understanding of hazardous organics released at fire scenes.Deployment of this portable instrumentation provides first responders with a rapid,on-site screening tool to appropriately manage the run-off water from firefighting activities.This ensures that environmental and human health is proactively protected.

Rapid on-site identification of hazardous organic compounds at fire scenes using person-portable gas chromatography-mass spectrometry(GC-MS)—part 1:air sampling and analysis

Recent advancements in person-portable instrumentation have resulted in the potential to provide contemporaneous results through rapid in-field analyses.These technologies can be utilised in emergency response scenarios to aid first responders in appropriate site risk assessment and management.Large metropolitan fires can pose great risk to human and environmental health due to the rapid release of hazardous compounds into the atmosphere.Understanding the release of these hazardous organics is critical in understanding their associated risks.Person-portable gas chromatography-mass spectrometry(GC-MS)was evaluated for its potential to provide rapid on-site analysis for real-time monitoring of hazardous organic compounds at fire scenes.Air sampling and analysis methods were developed for scenes of this nature.Controlled field testing demonstrated that the portable GC-MS was able to provide preliminary analytical results on the volatile organic compounds present in air samples collected from both active and extinguished fires.In-field results were confirmed using conventional laboratory-based air sampling and analysis procedures.The deployment of portable instrumentation could provide first responders with a rapid on-site assessment tool for the appropriate management of scenes,thereby ensuring environmental and human health is proactively protected and scientifically informed decisions are made for the provision of timely advice to stakeholders.

An internal cooling grinding wheel:From design to application

The cooling and lubrication conditions during the grinding process significantly impact the nickel-based superalloy’s final service performance.The existing jet cooling and heat pipe technology can solve the heat conduction problem in the grinding process of superalloy.Still,managing cooling,lubrication,and chip removal are difficult.This paper describes the design and fabrication of a novel central fluid-through internal cooling slotted grinding wheel with an ordered grain pattern to improve the grinding machinability of a nickel-based superalloy.The pressurized grinding fluid was ejected into the grinding zone via the pipe and tool holder from the lower-end face of the inner cooling wheel.The structure of the grinding wheel was optimized using computational fluid dynamics(CFD).The flow field in the grinding area achieved the highest overall flow rate,distribution homogeneity,and effective exit flow when the internal flow channel had four throughholes.The exit for the inner runner is located at the abrasive edge and diamond staggered pattern.Single-layer brazing was used to create cubic boron nitride(CBN)abrasive rings with various abrasive patterns.The internal cooling wheel matrix and various components were prepared according to the optimized grinding wheel geometry model.A grinding test bench was built to conduct an experimental study of grinding the nickel-based alloy GH4169.The results show that,under the same conditions,a diamond-shaped staggered pattern obtains lower grinding temperature,lower surface roughness,better surface morphology,and more significant residual compressive stress distribution than an abrasive cluster diagonal circular staggered pattern or disordered pattern.The average effective flow rate calculated by CFD is increased by 42.3%when compared to the disordered pattern.In the experiment,compared to the disordered arrangement,with the increase of grinding wheel’s rotating speed and coolant pressure,the average grinding temperature of abrasive grain with diamond-interleaved arrangement decreases by 58.2%and 51.7%respectively,and its surface hardening degree decreases by 11.1%and 11.7%respectively.

Parameter Optimization and Precision Enhancement of Dual-Coil Eddy Current Sensor

To enhance the measurement precision of eddy current sensor in particular environments such asextreme temperature changes and limited available space in aerospace, we optimized the structural parameters ofthe traditional dual-coil eddy current sensor probe by electromagnetic field analysis and finite element simulationmodeling, and further presented the criteria for determining the optimal coil distance of the dual-coil probe. Thesimulation results are verified by setting up an experimental platform. For the extreme temperature environment,the displacement measurement error caused by the full range temperature variation of the dual-coil sensor underthe optimal distance is less than 21.0% of that of the single-coil sensor. On this basis, we analyzed and verified thethermal stability of the structurally optimized dual-coil eddy current sensor. After temperature compensation,the displacement measurement accuracy can reach 14.9 times more accurate than that of the single-coil sensor.The method proposed in this paper can provide a design reference for the structural optimization of the axialdual-coil eddy current sensor probe.

3D-QSAR Models of Anti-tumor Activity for Histone Deacetylase Inhibitors Containing Dihydropyridin-2-one

A 3D-QSAR study was conducted to analyze the anti-tumor activity(pHs,s=1,6)of dihydropyridin-2-one containing histone deacetylase inhibitor(DHDACi)to histone deacetylase(HDACs,s=1,6)by the comparative molecular field analysis(CoMFA)method.The predicting model was established based on the training set of 22 compounds,which was verified by the test set of 6 compounds containing template molecule.The results showed that the contributions of steric and electrostatic fields to pH1 are 37.6%and 62.4%,and those to pH6 are 44.6%and 55.4%,respectively.The coefficients of the cross-validation(Rcv2)and the non cross-validation(R2)are 0.574 and 0.947 for pH1,and 0.488 and 0.884 for pH6,respectively.The models were then used to predict the activities of the compounds for the training and testing sets.The results indicated that the models had strong stability and good predictability.Based on the 3D contour maps,several new potential inhibitors with higher anti-tumor activity were designed.However,the effectiveness of these potential inhibitors is still needed to be verified by the experimental results.

Isosteric design of friction-reduction and anti-wear lubricant additives with less sulfur content

To reduce harmful sulfur content in lubricant additives, making use of isosterism has been shown to be an effective strategy. When thiobenzothiazole compounds were used as templates, the exchange of sulfur atoms in the thiazole ring with oxygen atoms and NH groups produced twelve isosteres. Similarly, 2-benzothiazole- S-carboxylic acid esters were used as template molecules to produce six isosteres. About 30% of the isosteres exhibited a satisfactory deviation of ±5% relative to the template, ignoring the specific changes in the base oils, the differences in molecular structure, and the friction or wear properties. The template molecules and isosteres in triisodecyl trimellitate exhibited better tribological properties than in trimethylolpropane trioleate or bis(2- ethylhexyl) adipate. Comparative molecular field analysis(CoM FA)- and comparative molecular similarity index analysis(CoMSIA)-quantitative structure tribo-ability relationship(QSTR) models were employed to study the correlation of molecular structures between the base oils and additives. The models indicate that the higher the structural similarities of the base oils and additives are, the more synergetic the molecular force fields of the lubricating system are; the molecular force fields creating synergistic effects will improve tribological performance.

CoMFA Model of Anti-tumor Activity for Fluoroquinolon-3-yl s-Triazole Sulfide-ketone Derivatives and Implications for Molecular Design

Comparative molecular field analysis(CoMFA)techniques were used to perform three-dimensional quantitative structure-activity relationship(3D-QSAR)studies on the anti-tumor activity(pIH and pIC)of 28 fluoroquinolon-3-yl s-triazole sulfide-ketone derivatives(FQTSDs)against two cancer cell lines,including human hepatoma Hep-3B cells and human pancreatic cancer Capan-1 cells.23 compounds were randomly selected as the training set to establish the prediction models,which were verified by the test set of 6 compounds containing template molecule.The obtained cross-validation(Rcv2)and non-cross-validation correlation coefficients(R2)of the CoMFA models were 0.477 and 0.850 for pIH,and 0.421 and 0.836 for pIC,respectively.The contributions of steric and electrostatic fields to pIH were determined to be 48.1%and 51.9%,and those to pIC were 49.4%and 50.6%,respectively.The CoMFA models were then used to predict the activities of the compounds in the training and testing sets,and the models had a strong stability and good predictability.Based on the 3D contour maps,four novel FQTSDs with a higher anti-tumor activity were designed.However,the effectiveness of these novel FQTSDs is still needed to be verified by experimental results.

Study on the Biological Activity of 3-Aroyl-5-substituted Thiophene Derivatives Based on the CoMFA Method

A three-dimensional quantitative structure-activity relationship(3 D-QSAR) study was conducted to analyze the A1 AR density(Bmax) of 56 3-aroyl-5-substituted thiophene derivatives(ASTDs) in human A1 Chinese hamster ovary(hA1 CHO) membranes by the comparative molecular field analysis(CoMFA) method. A training set of 45 compounds was used to establish the predictive model, which was verified by the test set of 17 compounds containing template molecule and 5 newly designed molecules. The cross-validation(R2 cv) and non-cross-validation(R2) coefficients of the training set were 0.655 and 0.959, respectively. The model was used to predict the activities of the compounds of the training and test sets, and the results indicated that the models had strong stability and good prediction ability. According to model analysis, the contribution of steric and electrostatic fields was 51.4% and 48.6%, respectively. Based on the 3 D contour maps, five excellent ASTDs agonists were designed, which need to be further verified by biomedical experiments.

CoMFA Model and Molecular Design of Anti-excitatory Activity for Benzodiazepinooxazole Derivatives against Mice

A 3D-QSAR study was conducted to analyze the anti-excitatory activity(p E)of benzodiazepinooxazole derivatives to mice by the comparative molecular field analysis(CoMFA)method.Among the 54 active molecules,a training set of 46 compounds was randomly selected to construct the CoMFA model;the remaining compounds,together with template molecule(No.54)and two newly designed molecules constitute a test set of 17 compounds to validate the model.The obtained cross-validation coefficient(R_(cv)^(2)),the non-cross validation coefficient(R^(2)),and the test value F of the CoMFA model for training set are 0.516,0.899,and 57.57,respectively.The model was used to predict the activities of all compounds in the training and testing sets,and the results indicated that the model had good correlation,strong stability and good predictability.Based on the 3D contour maps,eight novel benzodiazepinooxazole derivatives with higher anti-excitatory activity were designed.However,the effectiveness of these novel benzodiazepinooxazole derivatives is still needed to be verified by the experimental results.

CoMFA Study on Anti-proliferative Activity of Fluoroquinolone Amide Derivatives

The in vitro anti-proliferative activity(pICi,i=hp,ca,hl)of fluoroquinolone(rhodanineα,β-unsaturated ketone)amide compounds,referred to as“fluoroquinolone amide derivatives(FQADs)”towards Hep-3B,Capan-1 and HL60 cells,was studied by the 3D-QSAR method of comparative molecular field analysis(CoMFA).Based on the training set of 14 compounds,the prediction model was established,which was further verified by the test set of 5 compounds with template molecule included.It is found that steric and electrostatic fields contribute 66.8%and 33.2%to pIChp,61.4%and 38.6%to pICca,and 61.5%and 38.5%to pIChl,respectively.The Rcv 2(i.e,cross-validation coefficient)is 0.324,0.381,and 0.421 for pIChp,pICca,and pIChl,respectively,while the corresponding R2(i.e,non-cross-validation coefficient)all reach 0.999.Then,the models were employed to estimate the activities of the training and test compounds,and the results show that the stability and predictability of developed models are very satisfactory.According to the contour maps of steric and electronic fields,bulky groups linked to 2-,3-,4-positions of phenyl ring,and electropositive groups near the 4-position and electronegative groups far away may increase the anti-proliferative activity.Using the information provided by the 3D contour maps,four new FQADs owing higher antiproliferative activity were designed,but their effectiveness should be further tested by experiments.

3D-QSAR Studies on the Imidazopyrimidine Derivatives

Comparative molecular field analysis(CoMFA) and comparative molecular similarity indices analysis(CoMSIA) for imidazopyrimidine derivatives were performed to get the molecular active conformation selection, molecular alignment, as well as the establishment of corresponding 3 D-QSAR model. The model established by this method has good ability to predict such compounds. For CoMFA model, the cross-validated q2 and non-cross-validated r2 values are 0.665 and 0.872, respectively. The best q2 value for CoMSIA model is 0.632 and r2 value is 0.923. Using this information and the three-dimensional equipotential map for molecular design can theoretically obtain some new antibacterial drugs with higher activity. There are two newly designed molecules with activity values of 7.921 and 7.872, which are higher than that of the template molecule No. 12 with an activity value of 7.850, and the QSAR research results can provide a theoretical reference for the synthesis of new drugs.

Construction of the Molecular Structure Model of the Zhaotong Lignite Using Simulation and Experiment Data

Aiming to better understand the physiochemical properties of lignite, we select Zhaotong lignite as object and adopt simulation and experiment data to construct its molecular structure. Firstly, the important parameters including carbon skeleton, valence state and functional group of the sample are obtained by ultimate analysis, 13 C NMR, XPS and Py-GC/MS. Results indicate that the ratio of aromatic carbon and aromatic bridge carbon to surrounding carbon of the sample are 40.32% and 0.14, respectively. Such results imply that the aromatic structure of the sample is dominated by benzene and naphthalene. Moreover, the ratio of aliphatic carbon is 51.55%, and the aliphatic structure is mainly comprised by methyl, methylene, quaternary carbon and oxygen-aliphatic carbon. Oxygen atoms principally exist in ether, carbonyl and carboxyl groups, of which ether accounts for 70.2%. Additionally, the contents of pyridine, pyrrole and quaternary nitrogen are 25.2%, 46.3% and 13.0%, respectively. Based on the aforementioned results, the molecular structure model of Zhaotong lignite is constructed by the method of computer-aided molecular design. Subsequently, the molecular formula of Zhaotong lignite is calculated as C;H;O;N;. Finally, in order to verify the reasonability of the constructed model, the 13 C NMR of the molecular structure model is simulated by employing the basis set of GIAO/6-31G at the Gaussian 09 computing platform. These simulated results agree well with the experimental ones, which suggests that the molecular structure model of Zhaotong lignite is accurate and reasonable.

Heat Transfer and Friction Characteristics of Printed Circuit Heat Exchangers with Different Channel Structures for S-CO_(2) Power System

Printed circuit heat exchanger(PCHE)has been widely used in supercritical carbon dioxide(S-CO_(2))power systems because of its high heat transfer efficiency and good compactness.However,due to the large variety of PCHE configurations,channel selection in practical applications lacks a basis.Therefore,this paper discussed the heat transfer and friction characteristics and the synergy of three fields in the channel under the guidance of the field synergy principle for four typical PCHE channels.Additionally,the comprehensive performance of four channels was compared.Finally,the heat transfer and friction factor correlations for S-CO_(2)in four channels were established.The findings demonstrate that the synergy of velocity and pressure fields of the straight channel PCHE is better(β≈180°),so its resistance loss is relatively small.The zigzag and sinusoidal wavy channels and the airfoil fins can reduce the angle a between the temperature gradient and velocity,thus enhancing the heat transfer.The sinusoidal wavy channel can reduce flow resistance compared to the zigzag channel due to the rounded corners.The streamlined airfoil structure can guide the flow and reduce backflow,thus reducing resistance losses.In the range of Re studied in this paper,the maximum error of the proposed heat transfer and friction factor correlations of PCHE is 7.0%,which shows good fitting accuracy.The research in this paper can provide a reference for the selection and design of PCHE with different channel configurations.