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Cobalt-doped silica organic-inorganic (Co/SiO2) materials were prepared by sol-gel technique using tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) as silicon precursors and Co(NO3)2...

To explore the influence mechanism of La doping on the arc erosion resistance of Ag/SnO2 contact materials, SnO2 and La-doped SnO2 are prepared by a chemical coprecipitation method, and then Ag/SnO2 and La-doped Ag/SnO2 contact materials are prepared by a powder metallurgy process. The microstructures and phase structures of the Ag/SnO2 and La-doped Ag/SnO2 contact materials before and after arc erosion are analyzed. A laser-simulated arc is used as the experimental arc to explore the micromorphology and physicochemical properties of SnO2 and La-doped SnO2 after laser-simulated arc erosion. The results show that the density, hardness and conductivity of the La-doped Ag/SnO2 contact material all increase first and then decrease with an increasing La content, reaching their highest values at a La/Sn molar ratio of approximately 0.25. La doping improves the dispersion of SnO2 in the Ag matrix and reduces the mass loss of the La-doped Ag/SnO2 contact material during the arc erosion process. Under the action of a laser-simulated arc, although both parts of the SnO2 and La-doped SnO2 transform into SnO, most of the SnO2 sample forms large aggregates, while the La-doped SnO2 sample forms small, spherical particles that are well dispersed. Finally, a mechanism is proposed whereby La doping enhances the arc erosion resistance of Ag/SnO2 contact materials.

Two methyl-modified Al2O3/SiO2 xerogels, i. e. AIP-Al2O3/MSiO2 and ANN-Al2O3/MSiO2 xerogels, were prepared using aluminum isopropoxide and aluminum nitrate nonahydrate as the aluminum precursors, respectively. The appearance, density, viscosity, Gibbs activation energy for viscous flow and reaction rate constant of the sols were analyzed and compared. Their microstructures were characterized by means of powder X-ray diffraction, Fourier transform infrared spectroscopy, scanning electron microscopy and nitrogen adsorption–desorption measurements. The results show that the Al–O–Si bond is formed in the AIP-Al2O3/MSiO2 and ANN-Al2O3/MSiO2 xerogels. The ANN-Al2O3/MSiO2 sol has a smaller mean particle size and greater sol stability than the AIP-Al2O3/MSiO2 sol. Meanwhile, the ANN-Al2O3/MSiO2 xerogel has a smaller pore size and higher porosity. The total pore volume and specific surface area of the ANN-Al2O3/MSiO2 xerogel are 27.27% and 29.36% larger than those of the AIP-Al2O3/ MSiO2 sample, respectively. The saturated adsorption capacity of the ANN-Al2O3/MSiO2 xerogel to methylene blue is 7.15% larger than that of the AIP-Al2O3/MSiO2 xerogel.

With methyltriethoxysilane as hydrophobic precursors and aluminum isopropoxide as the aluminum source, the Al2O3/SiO2 sols and their gel materials were prepared. The effects of aluminum content (nA...

A highly efficient asymmetric synthesis of the IDO inhibitor navoximod, featuring the stereoselective installation of two relative and two absolute stereocenters from an advanced racemic intermediate, is described. The stereocenters were set via a crystallization-induced dynamic resolution along with two selective ketone reductions: one via a biocatalytic ketoreductase transformation and one via substrate-controlled hydride delivery from LiAlH(O

In order to explore how Cu doping improves the wettability between Ag and SnO2 of Ag/SnO2 contact material, the physical and chemical changes of pure SnO2 and Cu-doped SnO2 powders at a high temperature were studied using a laser simulated arc. The results show that some of the SnO2 grows preferentially along the (211) and (101) crystal planes, and the other part changes to SnO preferentially growing along the (101) crystal plane. SnO2 particles with SnO make contact with each other under the action of the simulation arc to form large agglomerate particles. Meanwhile, the deposition of gasified SnO2 during the arc process aggravates the formation of SnO2 agglomerates. However, Cu doping reduces the gasified deposition of SnO2 during the arc process, and inhibits the preferred growth of SnO2 along the (211) and (101) crystal planes and the change from SnO2 to SnO at a high temperature. Furthermore, Cu doping induces SnO2 grains to redistribute along a specific direction to form nanoneedle assembled Cu-doped SnO2 hierarchical nanostructures during the arc process. Finally, a mechanism of Cu doping which improves the interfacial wettability between Ag and SnO2 of Ag/SnO2 contact material is proposed.

Over a full molar fraction range, for binary mixtures of x N-methylimidazole (hereafter abbreviated to N-mim) + (1 − x) water, +methanol, +ethanol, +1-propanol, +2-propanol, the mass density and sound velocity at (288.15, 298.15, 308.15, 318.15, 328.15) K, the mixing enthalpy at 298.15 K, and 1H NMR measurements, combined with the Ab initio calculations, have been carried out. The excess molar volume, excess average volume expansivity, excess sound velocity, excess isentropic compressibility, and the molar mixing enthalpy were calculated and fitted to a Redlich-Kister equation. The partial molar enthalpy of N-mim, the difference between the partial molar volume and the molar volume of N-mim, and the protons chemical shift changes were calculated and compared. The chemical shifts of N-mim protons, hydroxyl protons, and α-H (proton on the carbon atom next to the –OH group) of alcohols in the mixtures containing alcohols were explained by a model proposed by Gupta et al.. The properties indicate that the intermolecular interactions between unlike molecules are stronger than those between like molecules. An increase in temperature has a greater influence on the mixture containing water than on pure components, and has a greater influence on pure components than on mixtures containing alcohols. The predominant interactions between unlike molecules are hydrogen-bonded complexes in the mixture containing water, and are N-mim: alcohols = 1:1 hydrogen-bonded networks in the mixtures containing alcohols, where the alkyl groups of alcohols are electron-withdrawing groups, and the methyl group of N-mim is an electron-donating group. Ab initio calculations proved that the N⋯HO hydrogen bond in the mixtures is more stable and stronger than HO⋯HO in pure water or in pure alcohols and N⋯HC in pure N-mim. The strength sequence of the intermolecular interactions between unlike molecules for the mixtures at 298.15 K is N-mim–water > N-mim–methanol > N-mim–ethanol > N-mim–1-propanol ≥ N-mim–2-propanol.

Methyl-modified, cobalt-doped silica (Co/MSiO2) materials were synthesized by sol-gel technique calcined in N2 atmospheres, and membranes were made thereof by coating method. The effects of Co/Si molar ratio (nCo) on the physical-chemical constructions of Co/MSiO2 materials and microstructures of Co/MSiO2 membranes were systematically investigated. The gas permeance performance and hydrothermal stability of Co/MSiO2 membranes were also tested. The results show that the cobalt element in Co/MSiO2 material calcined at 400 °C exists not only as Si–O–Co bond but also as Co3O4 and CoO crystals. The introduction of metallic cobalt and methyl can enlarge the total pore volume and average pore size of the SiO2 membrane. The activation energy (Ea) values of H2, CO2, and N2 for Co/MSiO2 membranes are less than those for MSiO2 membranes. When operating at a pressure difference of 0.2 MPa and 200 °C compared with MSiO2 membrane, the permeances of H2, CO2, and N2 for Co/MSiO2 membrane with nCo = 0.08 increased by 1.17, 0.70, and 0.83 times, respectively, and the perm-selectivities of H2/CO2 and H2/N2 increased by 27.66% and 18.53%, respectively. After being steamed and thermally regenerated, the change of H2 permeance and H2 perm-selectivities for Co/MSiO2 membrane is much smaller than those for MSiO2 membrane.

For a binary mixture of x N-methylimidazole (hereafter abbreviated as N-mim) + (1 − x) ethyl acetate (hereafter abbreviated as EAC), the density, sound velocity, viscosity and refractive index at (288.15, 298.15, 308.15, 318.15, and 328.15) K, mixing enthalpy at 298.15 K, and 1H NMR measurements combined with the ab initio calculations were carried out over a full molar fraction range. The density, sound velocity, isentropic compressibility, refractive index, viscosity, Gibbs energy of activation of viscous flow and the isobaric thermal expansivity were correlated with a polynomial well. The excess molar volume, excess isobaric thermal expansivity, isobaric thermal expansivity deviation, excess sound velocity, sound velocity deviation, excess isentropic compressibility, isentropic compressibility deviation, excess refractive index, refractive index deviation, excess logarithm viscosity, viscosity deviation, excess Gibbs energy of activation of viscous flow and the molar mixing enthalpy, were calculated and fitted to a Redlich-Kister polynomial. The activation parameters of viscous flow of the mixture, chemical shift changes of N-mim and EAC protons, interaction energy and second-order perturbation stabilization energy of 2-CH···O C, 2-CH···N and CH···O H-bonds were calculated. The mixing process of N-mim with EAC is an endothermic process with volume contraction. The energy to break the like molecular interactions is bigger than that to form dislike molecular interactions, and the volume contraction is mainly attributed to both the free volume difference and the more effective steric accommodation of molecules in the mixture. The 2-CH···O C and 2-CH···N H-bonds are approximately equivalent in dimers, 2-CH···O C H-bond in dimer (N-mim + EAC) is stronger and more stable than the CH···O H-bonds in EAC dimer. The amount of 2-CH···O C H-bond reaches a zenith at x ≈ 0.5. The formation of 2-CH···O C H-bond leads to the electron density rearrangement of the N-mim and EAC molecules, where the electron densities of the N-mim and EAC protons decrease and increase, respectively.

In order to evaluate the effect of Al on the enhancement of the sensor performance of SnO2 prepared at a low sintering temperature, the Al-doped SnO2 powder was prepared by a chemical co-precipitation method and sintered at a temperature of 400 °C. The gas-sensing response to ppm-level ethanol was investigated. The results showed that the gas-sensing response increased with an increase of the Al/(Al + Sn) molar ratio, and exhibited a maximum response at a molar ratio of 19%, then decreased drastically. A new possible influence mechanism is therefore proposed that, with the increase of Al/(Al + Sn) molar ratio, Al3+ ions form at first an interstitial solid solution in the SnO2 lattice, which causes a charge imbalance of the Al-doped SnO2 grains, and enhances the oxygen-adsorption onto the surface of SnO2 grains, thereby resulting in an improvement in the gas-sensing performance. At the molar ratio greater than 19%, excess Al3+ ions deposit on the surface of the SnO2 grains, which reduces the chance of contact between ethanol and the adsorbed oxygen, thereby reducing the gas-sensing performance.

Over the full molar fraction range, the density, viscosity, refractive index, conductivity and pH at the temperatures (298.15, 308.15, and 318.15) K, mixing enthalpy at T = 298.15 K, and 1H-NMR were measured for the binary mixtures of x N-methylimidazole (hereafter abbreviated to N-mim) + (1 − x) methanol, together with ab initio calculations. The thermodynamic parameters of activation for viscous flow were calculated and analyzed. The excess molar volume, viscosity deviation, deviation for the logarithm of viscosity, refractive index deviation and the excess refractive index, excess Gibbs energy of activation of viscous flow and the molar mixing enthalpy were calculated and fitted with a Redlich–Kister equation. The partial molar mixing enthalpies and the protons’ chemical shift changes of N-mim and methanol were calculated and explained. An increase in temperature leads to the excess molar volume becoming more negative, whereas the deviations for the logarithm of viscosity, viscosity deviation and the excess Gibbs energy of activation of viscous flow become less positive; in contrast the refractive index deviation and the excess refractive index become less positive at first and then become more positive. The activation of the viscous fluid is a more ordered process. The physicochemical properties, ab initio calculations, combined with the 1H-NMR results reveal that the molecular interactions among unlike molecules is stronger than that between like ones. There is an ionization process and hydrogen bond interaction between N-mim and methanol, the predominant interaction is N-mim:methanol = 1:1 hydrogen-bonded network, where the methyl groups of methanol and N-mim, respectively, are electron-withdrawing and electron-donating groups.

SiO2 and Pd/SiO2 nanocomposites were prepared using sol–gel method and characterized by X-ray diffraction, Fourier transform infrared spectra, scanning electron microscopy and different heating rate thermogravimetric–differential thermogravimetric analysis. The apparent activation energies (Ea) were calculated using the Kissinger’s and Ozawa’s methods. The most probable kinetic mechanism functions were obtained by master plot method. The entropy (ΔS≠), enthalpy (ΔH≠) and activation free energy (ΔG≠) were calculated using three methods. The results demonstrated that the thermal decomposition processes of both materials are the three-step reactions. After thermal condition in air atmosphere, the introduced hydrophobic Si–CH3 group in Pd/SiO2 gel materials was completely decomposed into inorganic composition, and the Pd element was transformed into PdO and metallic Pd. The Ea values obtained by Kissinger’s method are close to those by Ozawa’s method. The Pd-doping can increase the thermal decomposition activation energies and improve the thermal stability of SiO2 material. The decomposition mechanisms for the three stages are the assumed random nucleation and its subsequent growth, irrespective of the Pd-doping. Compared with SiO2 material, the thermal decomposition of Pd/SiO2 requires more energy due to the increasing ΔH≠. The ΔH≠ values calculated by method II are nearly equal to the Ea values from the Kissinger’s and Ozawa’s methods, which indicated that the thermodynamic parameters obtained by method II are the most accurate.

Pd-doped SiO2 organic-inorganic hybrid materials were synthesized using sol-gel technique. The Pd-doped SiO2 samples were calcined at the temperature 350°C for several different time in air atmosph...

Pd-doped methyl-modified SiO2 membrane materials were prepared by sol-gel technique with tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) as silicon precursors, PdCl2 as pall...

For a binary mixture of xN-methylimidazole (hereafter abbreviated to N-mim) + (1-x) water, over a full molar fraction range, the mass density, sound velocity, refractive index, viscosity, mixing enthalpy, conductivity, and pH at (298.15, 308.15, 318.15) K and 0.1 MPa, and 1H NMR and 13C NMR at room temperature combined with Ab initio calculations, were measured and carried out. The excess molar volume (VmE), sound deviation (∆u), refractive index deviation (∆nD), viscosity deviation (∆η), excess Gibbs energy of activation of viscous flow (∆G⁎E), molar mixing enthalpy (∆mixHm), 1H NMR chemical shift changes of N-mim and water protons (∆δH), 13C NMR chemical shift change of N-mim (∆δC), sum of the chemical shift changes (∑∆δH(N-mim), ∑∆δC), and the interaction energy, hydrogen bond length, second-order perturbation stabilization energy, electron density, and the electronic energy density of the trimer hydrogen-bonded complexes were calculated. The values of VmE, ∆u, ∆nD, ∆η, ∆G⁎E, and ∆mixHm were fitted to a Redlich-Kister equation. The extreme positions of these quantities and the chemical shift changes were compared and discussed with regard to the intermolecular interaction between N-mim and water, and a possible molecular interaction scheme was suggested for N-mim added to water. There occurs an ionization process and hydrogen-bonded interactions between N-mim and water. The ionization process may not be neglected at an infinite dilution of water, and hydrogen bonds predominate the primary interaction in the mixture. The predominant hydrogen-bonded complex in the mixture transforms with increasing x, which is consistent with the calculation results.

We report herein an efficient, stereocontrolled, and chromatography-free synthesis of the novel broad spectrum antibiotic GDC-5338. The route features the construction of a functionalized tripeptide backbone, a high-yielding macrocyclization via a Pd-catalyzed Suzuki-Miyaura reaction, and the late-stage elaboration of key amide bonds with minimal stereochemical erosion. Through extensive reaction development and analytical understanding, these key advancements allowed the preparation of GDC-5338 in 17 steps, 15% overall yield, >99 A % HPLC, and >99:1 dr.

Methyl-modified, cobalt-doped silica (Co/MSiO2) materials were synthesized by sol-gel technique calcined in N2 atmospheres, and membranes were made thereof by coating method. The effects of Co/Si molar ratio (nCo) on the physical-chemical constructions of Co/MSiO2 materials and microstructures of Co/MSiO2 membranes were systematically investigated. The gas permeance performance and hydrothermal stability of Co/MSiO2 membranes were also tested. The results show that the cobalt element in Co/MSiO2 material calcined at 400 °C exists not only as Si–O–Co bond but also as Co3O4 and CoO crystals. The introduction of metallic cobalt and methyl can enlarge the total pore volume and average pore size of the SiO2 membrane. The activation energy (Ea) values of H2, CO2, and N2 for Co/MSiO2 membranes are less than those for MSiO2 membranes. When operating at a pressure difference of 0.2 MPa and 200 °C compared with MSiO2 membrane, the permeances of H2, CO2, and N2 for Co/MSiO2 membrane with nCo = 0.08 increased by 1.17, 0.70, and 0.83 times, respectively, and the perm-selectivities of H2/CO2 and H2/N2 increased by 27.66% and 18.53%, respectively. After being steamed and thermally regenerated, the change of H2 permeance and H2 perm-selectivities for Co/MSiO2 membrane is much smaller than those for MSiO2 membrane.

As a further investigation on the binary mixtures containing 1-alkylimidazole, over the whole composition range and at atmospheric pressure, density, ρ, sound velocity, u, of binary system of x 1-ethylimidazole (abbreviated as 1-Eim) + (1-x) methanol, were measured at temperatures (293.15–328.15) K; refractive index, nD, and viscosity, η, of them were determined at temperatures (293.15–318.15) K; 1H NMR, δH, is measured at 288.15 K; isobaric thermal expansivity, αp, isentropic compressibility, κS, excess and deviation properties were calculated. The excess enthalpy and Gibbs free energy were predicted by COSMO-RS model. All the properties indicate that the real mixing process is a spontaneous enthalpy-driving process with liquid structure more ordered, and a lower temperature more benefits the process. There are stronger attractive interactions in the mixture than in pure liquids. The H-bonded interactions are the main attractive interactions in the mixture, followed by the electrostatic/misfit interaction and the Van der Waals force. A H-bonded network with a ration of methanol:1-Eim = 1:1 appears in the mixture, and reaches its maximum amount at x about 0.4; via the N···HO, the rearrangement of electron densities occurs where protons of 1-Eim and hydroxyl all show electron-donating abilities while methyl protons of methanol show electron-withdrawing ability.

A method for the trifluoromethylation of arylsilanes is reported. The reaction proceeds with [(phen)CuCF3 ] as the CF3 source under mild, oxidative conditions with high functional-group compatibility. This transformation complements prior trifluoromethylation of arenes in several ways. Most important, this method converts arylsilanes formed by the silylation of aryl C-H bonds to trifluoromethylarenes, thereby allowing the conversion of arenes to trifluoromethylarenes. The unique capabilities of the reported method are demonstrated by the conversion of a C-H bond into a C-CF3 bond in active pharmaceutical ingredients which do not undergo this overall transformation by alternative functionalization processes, including a combination of borylation and trifluoromethylation.

In order to explore the properties and molecular interactions in the binary systems of 1-alkylimidazole with molecular solvents, the system of x 1-ethylimidazole (herein referred to as 1-Eim) + (1-x) water, in the temperature range (288.15–328.15) K, the density ρ, sound velocity u, viscosity η, refractive index nD, pH and conductivity κ, and the 1H NMR δH, were measured at atmospheric pressure; the excess molar enthalpy HmE, the excess molar Gibbs free energy GmE, and the excess molar entropy SmE were predicted from the COSMO-RS model. The experimental and predicted properties indicate that the H-bonded interactions are the predominant interactions over the whole composition range. 1-Eim protons share more electron densities than water protons via the H-bonds, which are stronger between dissimilar molecules than between similar ones. The stable H-bonded structure of water molecules breaks when x is about 0.1, while the stable H-bonded structure of 1-Eim molecules forms when x is about 0.9. Temperature affects the H-bonded interactions more in the case of dissimilar molecules than similar molecules, especially in the water-rich region. The real mixing process is an enthalpy-driving spontaneous process with the liquid structure more ordered. A lower temperature more greatly benefits spontaneous mixing.

Since ionic liquids are increasingly employed as separation media in separation technologies, the development of thermodynamic model for design and optimization of the corresponding separation operations is very urgent. At present, the widely used thermodynamic models treat ionic liquid as a non-electrolyte or strong electrolyte. Although the calculation results are close to the experimental results, the treatment of ionic liquid does not consistent with the physical fact that ionic liquids ionize in solution, even in pure ionic liquid. In this work, we proposed a modified model for the calculation of the phase behavior of ionic liquid containing systems. The model combines a term of the modified Debye-Huckel type with a UNIQUAC equation and treats ionic liquid as a weak electrolyte, using an empirical expression to describe the ionization of ionic liquid. The new model has been utilized to correlate the vapor-liquid equilibrium, liquid-liquid equilibrium, solid-liquid equilibrium data as well as infinite dilution activity coefficient for ionic liquid containing systems with high accuracy. Besides, the model can be used to quantitatively describe the ionization behavior of ionic liquid.

A method for the trifluoromethylation of arylsilanes is reported. The reaction proceeds with [(phen)CuCF3] as the CF3 source under mild, oxidative conditions with high functional-group compatibility. This transformation complements prior trifluoromethylation of arenes in several ways. Most important, this method converts arylsilanes formed by the silylation of aryl C−H bonds to trifluoromethylarenes, thereby allowing the conversion of arenes to trifluoromethylarenes. The unique capabilities of the reported method are demonstrated by the conversion of a C−H bond into a C−CF3 bond in active pharmaceutical ingredients which do not undergo this overall transformation by alternative functionalization processes, including a combination of borylation and trifluoromethylation.

A direct oxidative C–H amination affording 1-acetyl indolecarboxylates starting from 2-acetamido-3-arylacrylates has been achieved. Indole-2-carboxylates can be targeted with a straightforward deacetylation of the initial reaction products. The C–H amination reaction is carried out using a catalytic Pd(II) source with oxygen as the terminal oxidant. The scope and application of this chemistry is demonstrated with good to high yields for numerous electron-rich and electron-poor substrates. Further reaction of selected products via Suzuki arylation and deacetylation provides access to highly functionalized indole structures.

Two Schiff base compounds, 2-[(3-dimethylaminopropylimino)methyl]phenol (L1) and 2-bromo-4-chloro-6-[(3-methylaminopropylimino)methyl]phenol (L2), react with zinc bromide in methanol solutions, respectively, to give two mononuclear complexes, [ZnBr2L1] (1) and [ZnBr2L2]· 0.5H2O (2). Both complexes were characterized by physico-chemical and spectroscopic methods. X-ray crystallography indicates that the Zn atom in each complex is in a tetrahedral coordination.

A tetradentate Schiff base compound 2-[(2-dimethylaminoethylimino)methyl]-6-methoxyphenol (HL) reacts with cadmium nitrate and ammonium thiocyanate in a methanol solution to give a dinuclear complex [Cd2L2(μ1,1-NCS)(NCS)(OH2)]. The complex was characterized by physico-chemical and spectroscopic methods. X-ray crystallography indicates that each Cd(II) atom is in a distorted octahedral coordination. The two metal atoms are bridged by one phenolate O and one end-on thiocyanate groups, with the distance of 3.399(3) A.

The densities of the ternary-pseudobinary mixtures [(styrene + ethyl acetate or benzene) + (N-methyl-2-pyrrolidone + ethyl acetate or benzene)], formed by adding the third component (ethyl acetate or benzene) to the binary system (styrene + ethyl acetate), have been measured as a function of composition by means of a vibrating-tube densimeter at atmospheric pressure at 298.15 K. The excess molar volumes V E were calculated from the densities and correlated using the Redlich–Kister equation to estimate the coefficients and standard errors. The experimental and calculated quantities are used to discuss the mixing behavior of the components. The results show that the third component, ethyl acetate or benzene, have quite different influences on the interaction between styrene and N-methyl-2-pyrrolidone.

Density of three binary mixtures formed by N,N-dimethylformamide (DMF) with aromatic hydrocarbon (one of benzene, toluene, and ethylbenzene) has been determined over the full range of compositions at the temperatures range (293.15 to 353.15) K and atmospheric pressure using a vibrating-tube densimeter. From these experiments, excess molar volumes ( V m E ) could be calculated and fitted by the fourth-order Redlich–Kister equation, so the coefficients and the standard error (σ) could be got. Our result shows V m E decreases when temperature increases in the studied systems.

The three-liquid-phases equilibria data of the quaternary system water (1) + formamide (2) + cyclohexane (3) + diethylene glycol monobutyl ether (4) in the tricritical region are reported. It has been found that the mass fraction of formamide in (formamide + water) controls the size of the three-phase region and the approach to the tricritical point. The experimental data have been analyzed to obtain the tricritical temperature and the tricritical composition.

Physiological acoustics is a very hot topic in modern acoustic research, which is to study the hearing mechanism and the utterance of both humans and animals. It could be divided into two main aspects: physical acoustics of the ear and physiological acoustics. In physiological acoustics, there are some common research methods, such as objective experimental testing, subjective feelings evaluation survey statistical method, building the physical acoustic model and numerical simulation methods, etc. The authors are researching the accurate mathematical model of equal loudness curves, critical band and masking effects, by applying the holographic concept with several biological factors which are required to build a standard model. The cochlear emission information should be extracted from wavelet analysis method and two hearing protection technologies are being developed by band shielding.