Free energy calculation of single molecular interaction using Jarzynski's identity method:the case of HIV-1 protease inhibitor system

Jarzynski＇ identity （JI） method was suggested a promising tool for reconstructing free energy landscape of biomolecular interactions in numerical simulations and ex- periments. However, JI method has not yet been well tested in complex systems such as ligand-receptor molecular pairs. In this paper, we applied a huge number of steered molec- ular dynamics （SMD） simulations to dissociate the protease of human immunodeficiency type I virus （HIV-1 protease） and its inhibitors. We showed that because of intrinsic com- plexity of the ligand-receptor system, the energy barrier pre- dicted by JI method at high pulling rates is much higher than experimental results. However, with a slower pulling rate and fewer switch times of simulations, the predictions of JI method can approach to the experiments. These results sug- gested that the JI method is more appropriate for reconstruct- ing free energy landscape using the data taken from experi- ments, since the pulling rates used in experiments are often much slower than those in SMD simulations. Furthermore, we showed that a higher loading stiffness can produce higher precision of calculation of energy landscape because it yields a lower mean value and narrower bandwidth of work distri- bution in SMD simulations.

Calculation of the Surface Energy of Pure Titanium

Anodic oxidation on pure titanium(α-Ti) surface causes the formation ofinterferential films with different colours,mainly golden,pink and blue.The col-our changes with the thickness of the ox-ide film.One of the factors,which influ-ences the growth rate of the film,may bethe grain surface energy.at least at the

A NEW AB INITIO CALCULATION METHOD OF INNER-SPHERE REORGANIZATION ENERGY

On the basis of the-improved self-exchange model of reorganization phenomenon and accurate potential functions from ab initio calculation at HFSCF 6-31G* and DZP levels a new calculation method was,presented for the inner-sphere reorganization energy, values for diatomic molecular redox couples in gas phase electron transfer process have been calculated. Results agree well with the experimental data, and the effectiveness and importance of this method have been demonstrated for calculation of inner-sphere reorganization energy in gas phase electron transfer process.

Calculation of Neutral Particle Energy Spectra in Tokamak by Using the Monte Carlo Method

Neutral particle energy spectra in the HT-7 tokamak are calculated by using the Monte Carlo method. It can reproduce the spectra measured in experiment. Differences of neutral particle energy spectra in higher and lower electron density plasma are discussed. Results show that the ion temperature given by neutral particle energy spectra is lower than the real ion temperature, but the deviation is within 10% if the ion temperature is less than 800 eV and thecentral chord-averaged electron density does not exceed 3 ×1013 cm-3. But for ion temperature higher than 1000 eV at the central chord-averaged density limit up to 5 ×1013 cm-3, the neutral particle energy spectra can still give the ion temperature within 10% deviation.

Analysis of a Critical Residue Determining Herbicide Efficiency Sensitivity in Carboxyltransferase Domain of Acetyl-CoA Carboxylase from Poaceae by Homology Modeling and Free Energy Simulation

Carboxyltransferase domain（CT） of acetyl-coenzyme A carboxylase（ACCase, EC 6.4.1.2） from a family of Poaceae is an important target of commercial herbicide APPs for controlling grass weed growth. As the abuse of APPs herbicides, the resistant ACCase due to the mutation of a single residue（Ile→Leu）, which is located in CT active site, is emergent in many populations and species of Poaceae. So it is urgent to understand the resistant mechanism so as to design new effect herbicides. Herein lies the complex of CT dimmer from Lolium rigidum and herbicide haloxyfop successfully constructed for wild type enzyme and Ile/Leu mutant, respectively, providing a basis for explaining the resistance from microscopic structure. Moreover, the binding free energy difference between wild type and mutant enzymes was predicted in good agreement with the known observation, and the various contributions to it were analyzed, by Molecular mechanics-Poisson-Boltzmann surface area（MM-PBSA） method. The results indicate the van der Waals interaction difference between the protein and inhibitor, -22.94 kJ/mol of CT wild type lower than that of mutant, is the major reason for resistance. Structure analysis further suggests that van der Waals interaction difference is originated from the steric hindrance between the side chain of mutated residue Leu and the chiral methyl group of haloxyfop. All these findings enhance the understanding of resistant mechanism of ACCase to herbicide by Ile/Leu mutation and provide an important clue for the rational design of high effective herbicides.

A comparison of the energy consumption and carbon emissions for different modes of transportation in open-cut coal mines

Transportation accounts for 80% of open-cut coal mine carbon emissions. With regard to the energy con- sumption and carbon emissions of transportation within an open-cut mine, this paper systematically compared the work and energy consumption of a truck and belt conveyor on a theoretical basis, and con- structed a model to calculate the energy consumption of open-cut mine transportation. Life cycle carbon emission factors and power consumption calculation model were established through a Process Analysis- Life Cycle Analysis （PA-LCA）. The following results were obtained： （1） the energy consumption of truck transportation was four to twelve times higher than that of the belt conveyor; （2） the C02 emissions from truck transportation were three to ten times higher than those of the belt conveyor; （3） with the increase in the slope angle for transportation, the ratio of truck to belt conveyor for both energy consumption and carbon emissions gradually decreased; （4） based on 2013 prices in China, the energy cost of transportation using a belt conveyor in open-cut coal mines could save 0.6-2.4 Yuan/（t kin） compared to truck transportation.

Study of the features of outburst caused by rock cross-cut coal uncovering and the law of gas dilatation energy release

To study the law of gas dilatation energy release of rock cross-cut coal uncovering face, according to the analysis of the physical parameters distribution features of coal and rock mass in front of crosscut face,the equations of elastic potential of coal and gas dilatation energy theory were set up to process a contrast calculation of the sizes of two kinds of energy. The results show that gas dilatation energy is the uppermost energy source causing outburst occurrence. Furthermore, the mathematical model of spherical flow field gas dilatation energy release was established and MATLAB software was applied to make a numerical calculation analysis on the law of gas dilatation energy release. The results indicate that the gas dilatation energy is closely related to gas parameters and its energy index does reflect the possibility of coal seam outburst.

A SIMPLE METHOD TO CALCULATE RESONANCE ENERGY

A very simple method to calculate resonance energies of conjugated hydrocarbons by counting carbon numbers was introduced.

Early Stage CAD-Compliant Energy Performance Assessment Method

A simple calculator for early stage energy performance assessment in residential buildings was developed and partially validated in this study. The calculator is based on the correlation of heat loss and energy need for heating and has fixed internal heat gains as intended for compliance assessment. With the calculator, the effect of any parameter implemented can be immediately seen on delivered and primary energy. Because of simple equations, it is suitable for implementation into CAD （computer aided design） design tools including basic BIM （building information modeling） data. Results showed that the accuracy of the correlation for the cases with practical relevance was not worse than 14% of the energy need of space heating. This applies for passive house insulation level; for less insulated building envelopes, the deviations were smaller. This 14% equals to only 3 kWh/（m2.a）, i.e., the percentage difference in the total delivered and primary energy was much lower because of other components in the energy balance. The deviations determined were implemented in the calculator as safety margin. Results prove that simple energy performance assessment based on specific heat loss coefficient is well justified for early stage energy analyses as well as for compliance assessment implemented in Estonian regulation.

Inclusion Modes of Berberine with β-Cyclodextrin in Aqueous Solution

The possible inclusion modes of berberine（Berb） with β-cyclodextrin（BCD） in aqueous solution were predicted by molecular docking,molecular dynamics（MD） simulation and binding free energy calculations.Firstly,the molecular docking result reveals that the docking conformations of Berb appeared in two clusters ranked in two opposite orientations.Then,10 ns MD simulation was performed separately on the lowest energy conformation of each orientation（Mode I and Mode II） obtained by molecular docking.Moreover,based on the trajectories from MD simulation,the binding free energies of the two different modes were calculated by the Molecular Mechanics/Poisson Boltzmann surface area（MM/PBSA） method.Through analyzing the binding free energies of Berb with BCD,we found that Mode II was the preferential inclusion mode,which was in good agreement with the experimental result.In addition,the computed results show that the main impetus for the complex was the van der Waals interaction,but the solvation energy and the entropy change produced an adverse effect on the complex.

Atomic Design of Polarity of GaN Films Grown on SIC（0001）

Ab initio total energy calculations are used to determine the interface structure of GaN films grown on 6H-SiC(0001)with different substrate reconstructions.The results indicate that GaN films grown on bare SiC(0001)are of the Ga-polarity,while GaN films grown on SiC(0001)with Si adlayer are of the N-polarity if there is no N-Si interchange at the interface.With the interchange,the GaN films are of the Ga-polarity.

Hydrothermal Synthesis and Crystal Structure of a Microporous Gallophosphate with 12-Membered Ring Channels:Ga_9(PO_4)_(12)(H_3TREN)(H_2TREN)_3·xH_2O

An open-framework gallophosphate, Ga_9(PO_4)_ 12[(H_3TREN)(H_2TREN)_3]·xH_2O was hydrothermally synthesized at 453 K with tris(2-aminoethyl) amine(TREN) as the organic template and characterized by single-crystal X-ray diffraction. Ga_9(PO_4)_ 12[(H_3TREN)(H_2TREN)_3]·xH_2O crystallized in a cubic space group I43m, with a=1.68552(3) nm and Z=2. The structure contains 12-membered ring channels and supercages of 1.434 nm in diameter, and is an analogue of Al_9(PO_4)_ 12(C_ 24H_ 91N_ 16)·17H_2O. Template-TREN in the supercage was different from triethylenetetraamine(TETA) used in the initial reaction mixture due to the construction transformation. The TETAs transformed into the TRENs due to the low interaction energy between the template and framework. We verified it via energy calculation and liquid state NMR.

Rapidly calculating the partition function of macroscopic systems

It has remained an open problem to accurately compute the partition function of macroscopic systems since the establishment of statistical physics. A rapid method approaching this problem was presented and was strictly tested by molecular dynamic （MD） simulations on Ar atoms in both dense gaseous and liquid states. The outcomes from the method on the internal energy and the work of isothermal expansion （and therefore the free energy） are in good agreement with the MD simulations, suggesting the method would be immediately applied in vast areas.

Sustainable Design of Turbofan Engine： A Computer-Aided Design and Finite Element Analysis

A compressive design and analysis of a turbofan engine is presented in this paper. The components of jet engine have been analyzed based on mechanical design concept. An attempt has been to select materials based on sustainability and green design considerations. The energy content （e） of the materials has been one of the parameters for material selection. The choice of material has a substantial impact on cost, manuthcturing process, and the life cycle efficiency. All components nose cone, fan blade, inlet shaft, including compressor has been solid modeled using Siemens NX 11.0 CAD software. The finite element analysis of every component was performed and found safe. A tolerance analysis was performed before assembly of the turbofan engine. A numerical analysis was completed on blade and inlet geometries to determine a more efficient turbofan engine. Thermal analysis was executed oi1 the cone and suitable corrections were made. Finally, the cost and the total energy were estimated to show how much energy is needed to manufacture a turbofan jet engine.

Ab initio calculations on accurate dissociation energy, equilibrium geometry, and analytic potential energy function for the 6~3Π state of ~7LiH molecule

The accurate dissociation energy and equilibrium geometry of the ball state of ^7LiH molecule is calculated using a symmetry-adapted-cluster configuration-interaction method in full active space. And the calculated results are 0.2580 eV and 0.1958 nm for the dissociation energy and equilibrium geometry, respectively. The whole potential energy curve for the b^3∏ state is also calculated over the internuclear separation range from about 0.10 to 0.54 nm. The results are fitted by the Murrell-Sorbie function. It is found that the Murrell-Sorbie function form, which is mainly used to fit the ground-state potential energy function, is well suitable for the excited triplet b^3∏ state. The vertical excitation energy from the ground state to the b^3∏ state is calculated to be 4.233 eV. Based on the analytic potential energy function, the harmonic frequency of 610.88 cm^-1 about this state is firstly estimated. Compared with other theoretical results, this work is the most complete effort to deal with the analytic potential energy function and the harmonic frequency of this state.

CALCULATION OF THE HYDRODYNAMIC CHARACTERISTICS OF A OWC WAVE ENERGY ABSORBER

This paper deals with the hydrodynamic response to waves of a 3-D OWC(oscillating water column)wave energy absorber with converging channel.The theoretical solutions are presented by means of three-dimensional GREEN function method.In the calculation,the flow field is divided into two subregions:an inside field and an outside one.In the outside field the solution is represented by oscillating sources distributed on the outer surface of the chamber of the absorber,while the solution of the inside field is expressed by Rakine source-distribution on the inner surface of the chamber.Both solutions are matched on the artificial interface.The calculated.values seem to agree reasonably well with experimental results.

Calculation of vibrational energy transition rates in acoustic relaxation processes for excitable gas molecules

To research the correlation between vibrational energy transition rates and acoustic relaxation processes in excitable gases, the vibrational relaxation theory provided by Tanczos [J. Chem. Phy3. 25, 439 （1956）] is applied to calculate the energy transition rates of Vibrational- Vibrational （V-V） and Vibrational-Translational （V-T） energy transfer in gas mixtures. The results of calculation for the multi-relaxation processes in various gas mixtures, consisting of carbon dioxide, methane, chlorine, nitrogen, and oxygen at room temperature, demonstrate that the acoustic energy stagnated in every vibrational mode is coupled with each other through V-V energy exchanges. The vibrational excitation energy will relax through the V-T de-excitation path of the lowest mode because of its fastest V-T transition rate, resulting in that only one absorption peak can be measured for most of excitable gas mixtures. Thus, an effective model is provided to analyze how the vibrational energy transition rates affect the characteristics of acoustic relaxation processes and acoustic propagation in excitable gas mixtures.

Think Home: A Smart Home as Digital Ecosystem

This work brings all new and advanced technology which is proposed for refinement and improvement in the existing electrification system at domestic as well as commercial levels including hotels, commercial complexes, apartments, rented floors and rooms. This advanced module will not only convey means of luxury but will also accomplish real-time energy monitoring and cost es-timation. This developed module will rule out entire re-wiring and will be fruitful at places where installation of a new meter was a problem. The new system after installation will offer means of comfort to the consumer, elderly as well as handicapped and disabled people in operating electric load with ease and comfort. Apart from this, it would also benefit the apartment/hotel owner’s and business personnel who have rented their property or portion of property and face problems in calculating energy bill.

Melting temperature of iron under the Earth’s inner core condition from deep machine learning

Constraining the melting temperature of iron under Earth’s inner core conditions is crucial for understanding core dynamics and planetary evolution.Here,we develop a deep potential(DP)model for iron that explicitly incorporates electronic entropy contributions governing thermodynamics under Earth’s core conditions.Extensive benchmarking demonstrates the DP’s high fidelity across relevant iron phases and extreme pressure and temperature conditions.Through thermodynamic integration and direct solid–liquid coexistence simulations,the DP predicts melting temperatures for iron at the inner core boundary,consistent with previous ab initio results.This resolves the previous discrepancy of iron’s melting temperature at ICB between the DP model and ab initio calculation and suggests the crucial contribution of electronic entropy.Our work provides insights into machine learning melting behavior of iron under core conditions and provides the basis for future development of binary or ternary DP models for iron and other elements in the core.

Investigation on the potential barrier to internal rotation in molecules——Ab initio calculation and energy partition of the internal rotation barrier in complex molecule H_3N-BH_3

Based on the ab initio/6-31Gcalculation, the potential barrier to internal rotation in mol-ecule HN--BHhas been studed by means of PD/LSF atomic charge model and Buckingham（exp--6-1）energy partition method. The results indicate that the order of the contributions of the componentsto the total energy barrier △E is |△V|（electrostatic） >|△V| （charge transfer）>|△V| （exchangerepulsion）>|△V| （dispersion）. For △Vthere are maxima at θ= 30°and 90°, and a saddle atθ= 60°. There are good linear relationships for the total barrier △E, △Vand △Vwith cos3θrespectively, and the same for the dipole moment from PD/LSF model (μ) and that from abinitio calculation (μ) vs. cos3θ respectively.