Solubility determination and comparison ofβ-HMX and RDX in two binary mixed solvents(acetonitrile+water,nitric acid+water)

In order to remove hexahydro-1,3,5-trinitro-1,3,5-triazine(RDX),the main impurity,in process of polymorphic transformation of octrahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine(HMX),the solubility ofβ-HMX and RDX in acetonitrile(ACN)+water in the temperature range of 288.15-333.15 K and in nitric acid(HNO_(3))+water in the temperature range of 298.15-333.15 K were measured by laser dynamic method.The results showed that the solubility of bothβ-HMX and RDX in binary mixed solvents increased monotonously as the temperature increase at a given solvent composition or with increasing of mole fraction of solvent(ACN and nitric acid).Solubility data were well correlated by the modified Apelblat equation,Jouyban-Acree model,Yaws equation and van't Hoff equation,and the Yaws equation achieved the best fitting results according to the relative error and the mean square error root.Furthermore,the solubility ofβ-HMX and RDX in binary mixed solvent was compared,based on the solubility difference and the solvent's own properties,the best separation degree ofβ-HMX and RDX was found when the mole fraction of nitric acid was 0.22 at room temperature,which provided data support for HMX crystallization in mixed solvent.The solubility differences between RDX andβ-HMX in mixed solvents were explained from the formation of intermolecular and intramolecular hydrogen bonds.

Crystallization thermodynamics of 2,4(5)-dinitroimidazole in binary solvents

2,4(5)-Dinitroimidazole(2,4(5)-DNI)is an important organic intermediate,and itself can also be used for energetic material.In this work,the solubility of 2,4(5)-DNI in(methanol+water,acetonitrile+water,acetone+water)binary solvents were measured by using a dynamic test method from 278.15 K to 323.15 K under 101.1 k Pa.The Jouyban–Acree model,van't Hoff–Jouyban–Acree model,Apelblat–Jouyb an–Acree model,Ma model,and Sun model were used to correlate the experimental data.The values of relative average deviation(RAD)and root-mean-square deviation(RMSD)were very small,indicating that the error between the experimental value and the correlated value was very small.The thermodynamic parameters such as dissolution enthalpy,dissolution entropy and Gibbs energy were calculated based on solubility data.High-purity of 2,4(5)-DNI was efficiently obtained by using cooling and dilution crystallization method.

Experimental determination of solubilities and＇supersolubilities of 2,2＇,4,4＇,6,6＇-hexanitrostilbene in different organic solvents

The laser monitor technique was used to determine solubilities and supersolubilities of HNS in N,N-dimethylformamide, dimethyl sulfoxide, acetonitrile, N-methyl-2-pyrrolidone and 1,4-butyrolactone. The experimental solubility values were correlated with λh equation, modified Apelblat equation and NRTL model. Furthermore, the dissolution enthalpy, dissolution entropy and the Gibbs energy of HNS were calculated by the experimental data. The results show that the solubilities of HNS in the above solvents increase with the increasing temperature. Besides, at the same temperature, the order of solubility is N-methyl-2-pyrrolidone > dimethyl sulfoxide > N,N-dimethylformamide > 1,4-butyrolactone > acetonitrile. The temperature dependence of predicted solubility is in agreement with the experimental data.

Solubility and metastable zone width measurement of 3,4-bis (3-nitrofurazan-4-yl) furoxan (DNTF) in ethanol + water

The solubility and supersolubility of 3,4-bis(3-nitrofurazan-4-yl)furoxan(DNTF) in ethanol + water at different operation were determined by laser monitoring system under atmospheric pressure to study the metastable zone width(MSZW). The modified Apelblat equation was adopted to correlate the experimental solubility data, and the correlation result showed perfect consistent with the experimental data. The standard dissolution enthalpy, standard dissolution entropy and Gibbs energy were calculated according to the experimental solubility data. The effect of the cooling rate, stirring rate, temperature and the concentration of ethanol + water on the MSZW was studied. It was found that the MSZW of DNTF increased with the increasing cooling rate, decreasing temperature, decreasing stirring rate and decreasing ratio of water. And the apparent nucleation order of DNTF in ethanol + water was calculated by the relationship between the cooling rate and the MSZW.

Determination and correlation solubility of m-phenylenediamine in (methanol, ethanol, acetonitrile and water) and their binary solvents from 278.15 K to 313.15 K

In this study, the solubility of m-phenylenediamine in four pure solvents(methanol, ethanol, acetonitrile and water) and three binary solvent(methanol + water),(ethanol + water) and(acetonitrile + water) systems were determined in the temperature ranging from 278.15 K to 313.15 K by using the gravimetric method under atmospheric pressure. In the temperature range of 278.15 K to 313.15 K, the mole fraction solubility values of m-phenylenediamine in water, methanol, ethanol, and acetonitrile are 0.0093–0.1533, 0.1668–0.5589,0.1072–0.5356, and 0.1717–0.6438, respectively. At constant temperature and solvent composition, the mole fraction solubility of o-phenylenediamine in four pure solvents was increased as the following order:water b ethanol b methanol b acetonitrile;and in the three binary solvent mixtures could be ranked as follows:(ethanol + water) b(methanol + water) b(acetonitrile + water). The relationship between the experimental temperature and the solubility of m-phenylenediamine was revealed as follows: the solubility of mphenylenediamine in pure and binary solvents could be increased with the increase of temperature. The experimental values were correlated with the Jouyban–Acree model, van’t Hoff–Jouyban–Acree model, modified Apelblat–Jouyban–Acree model, Sun model and Ma model. The standard dissolution enthalpy, standard dissolution entropy and the Gibbs energy were calculated based on the experimental solubility data. In the binary solvent mixtures, the dissolution of m-phenylenediamine could be an endothermic process. The solubility data,correlation equations and thermodynamic property obtained from this study would be invoked as basic data and models regarding the purification and crystallization process of m-phenylenediamine.

Determination and correlation solubility of 4-nitroimidazole in twelve pure solvents from 278.15 K to 323.15 K

In this paper,the solubility of 4-nitroimidazole in twelve pure solvents(toluene,benzene,1,4-dioxane,acetonitrile,ethyl acetate,acetone,GBL,ethanol,methanol,n-butanol,DMF and NMP)were determined by using the laser monitoring system from 278.15 K to 323.15 K under 101.1 k Pa,which are 0.00018–0.00070,0.00021–0.00073,0.00034–0.00092,0.00038–0.00142,0.00047–0.00120,0.00126–0.00303,0.00225–0.00517,0.00310–0.00724,0.00467–0.00982,0.00453–0.01940,0.01947–0.04652,and 0.04670–0.07452,respectively.At constant temperature,the mole fraction solubility of 4-nitroimidazole were increased as the following order:toluene<benzene<1,4-dioxane<(ethyl acetate or acetonitrile)<acetone<GBL<ethanol<(methanol or nbutanol)<DMF<NMP,and the solubility of 4-nitroimidazole in(ethyl acetate,acetonitrile)and(methanol,n-butanol)had an intersection point at 297.55 K and 281.85 K,respectively.The solubility of 4-nitroimidazole could be increased with increasing temperature in twelve pure solvents.The ideal model,modified Apelblat equation,polynomial empirical equation,andλh equation were used to correlate the experimental values.The experimental solubility values were employed to calculate the standard dissolution enthalpy,standard dissolution entropy and Gibbs energy.The dissolution of 4-nitroimidazole could be an endothermic process in twelve pure solvents.The determination and fitting solubility of 4-nitroimidazole have important guiding significance for the purification and crystallization of its preparation process.

Effect of Combined Application of Boron and Molybdenum Microelement Fertilizer on Cowpea Yield and Quality

Through field plot experiment,we research the influencing factors of cowpea yield and quality after applying boron and molybdenum microelement fertilizer. Results show that the application of boron and molybdenum microelement fertilizer can significantly increase the yield and improve the quality of cowpea. Compared with the control,yield per mu increases by 5. 08- 18. 86%; N content increases by 4. 27%-11. 28%; P content increases by 2. 13%- 13. 57%; K content increases by 2. 00%- 18. 48%; crude protein increases by 4. 16%-19. 94%; vitamin C increases by 2. 71%- 11. 79%; nitrate content decreases by 5%- 15%. Besides,it is better to combine boron with molybdenum than to use each of them separately.

Crystallization thermodynamics of 2,4(5)-dinitroimidazole in eleven pure solvents

2,4(5)-Dinitroimidazole(2,4(5)-DNI) is an important energetic material, and it is also an important precursor for the preparation of drugs and energetic materials. In this study, the solubility of 2,4(5)-DNI in eleven pure solvents(chlorobenzene, benzene, 1,2-dichloroethane, toluene, water, isopropyl alcohol,ethyl acetate, acetonitrile, methanol, 1,4-dioxane and acetone) were measured by using a dynamic test method from 278.15 K to 323.15 K under 101.1 kPa. Four solubility models were used to fit the experimental data, which were ideal model, modified Apelblat equation, polynomial empirical equation, and λh equation. Meanwhile, the relative average deviation and root-mean-square deviation between the experimental data and the fitted data were also calculated. Furthermore, the three thermodynamic parameters,i.e., dissolution enthalpy, dissolution entropy and Gibbs energy were obtained based on solubility data.Finally, the crude product of 2,4(5)-DNI was crystallized with acetone as solvent, and the purity of the crystalline product was greater than 99.5%.

Solubility and metastable zone width measurement of 2,4-diaminobenzenesulfonic acid in(H_(2)SO_(4)+H_(2)O)system

The equilibrium solubility of 2,4-diaminobenzenesulfonic acid and super solubility as well as metastable zone width were measured in(H_(2)SO_(4)+H_(2)O) system by the laser dynamic method at elevate temperature range from 298.15 K to 338.15 K.2,4-Diaminobenzenesulfonic acid solubility dependence on the temperature and solvent composition were correlated by the modified Apelblat equation,(CNIBS)/Redlich-Kister model and Jouyban-Acree model.The correlated results by three correlation models were in good accord with the experimental values according to relative average deviations(RD),root-mean-square deviations(RMSD),and correlation coefficients(R^(2)).The metastable zone width increased with temperature and sulfuric acid content.The dissolution enthalpy,dissolution entropy and the Gibbs energy were calculated from the experimental values,which indicated that dissolution process of the 2,4-diaminobenzenesulfonic acid was endothermic.The solubility and calculation models of 2,4-diaminobenzenesulfonic acid in(sulfuric acid+water)system could provide the basic data to the crystallization and purifying of the 2,4-diaminobenzenesulfonic acid.

A Preliminary Study on Patent Application and Management of Agricultural Scientific Research Institutions

At present,there is a contradiction between the rapid growth of the number of patents declared and authorized by agricultural scientific research institutions and the decline of the efficiency of invention patents year by year,and the low conversion rate of patents.This paper discusses the patent application quantity,authorization quantity and patent efficiency of the Tropical Crops Genetic Resources Institute,Chinese Academy of Tropical Agricultural Sciences,analyzes the present situation of its work and the main problems existing in patent management,and puts forward the relevant suggestions.

Preliminary Study on Management of Agricultural Scientific Research Projects in the New Situation

Project management of agricultural scientific research institutions is an important section of agricultural scientific research plan management. It is of great significance for sustainable development of scientific research work of scientific research institutions. According to a series of opinions and notices about scientific and technological system reform issued by the state,and combining current situations of management of scientific research projects in scientific research institutions,this paper made a preliminary study on management of agricultural scientific research projects in the new trend. Finally,on the basis of the current situations of management of agricultural scientific research projects,it came up with pertinent recommendations,including strengthening communication and cooperation and actively declaring projects,strengthening preliminary planning of projects and establishing project information database,reinforcing project process management,ensuring on-time and high quality completion of projects,and strengthening learning and improving quality of management personnel.

Current Situations of Competitive Scientific Research Projects for Agri-scientific Research Institutions: A Case Study of Tropical Crops Genetic Resources Institute of Chinese Academy of Tropical Agricultural Sciences

This paper collected and arranged competitive scientific research projects undertaken by Tropical Crops Genetic Resources Institute of Chinese Academy of Tropical Agricultural Sciences in 2003-2014. Through statistical analysis on quantity of projects,funded amount,age of person responsible,professional title of person responsible,academic degree of person responsible,research object,it discussed relevant characteristics and rules. Finally,it came up with pertinent measures and recommendations,in the hope of providing services for decision-making and scientific and technological management.

Construction and Establishment of Sci-tech Platform for Agricultural Scientific Research Institutions: A Case Study of Tropical Crops Genetic Resources Institute of Chinese Academy of Tropical Agricultural Sciences

Taking Tropical Crops Genetic Resources Institute( TCGRI) of Chinese Academy of Tropical Agricultural Sciences( CATAS) as an example,this paper discussed current situation of construction of sci-tech platform,analyzed existing problems,and finally came up with pertinent recommendations.

Management of Official Overseas Trips of Staff in Agri-scientific Research Institutions

Taking Tropical Crops Genetic Resources Institute( TCGRI) of Chinese Academy of Tropical Agricultural Sciences( CATAS) as an example,this paper discussed current situation of management of official overseas trips of staff in agric-scientific research institutions,analyzed existing problems,and finally came up with pertinent recommendations.

浅谈阿尔及利亚客滚船艉跳板建造原则工艺

对阿尔及利亚客滚船艉跳板建造的关键控制要点进行介绍,阐述了艉跳板建造各阶段的建造原则工艺,通过对艉跳板的建造流程、焊接工艺以及精度管理的有效把控,确保了艉跳板结构和铰链安装精度,实现艉跳板的安装与运行顺利,为后续客滚船艉跳板建造提供了宝贵经验。

EFFICIENT SPECTRAL METHODS FOR EIGENVALUE PROBLEMS OF THE INTEGRAL FRACTIONAL LAPLACIAN ONABALLOFANYDIMENSION

An efficient spectral-Galerkin method for eigenvalue problems of the integral fractional Laplacian on a unit ball of any dimension is proposed in this paper.The symmetric positive definite linear system is retained explicitly which plays an important role in the numerical analysis.And a sharp estimate on the algebraic system's condition number is established which behaves as N4s with respect to the polynomial degree N,where 2s is the fractional derivative order.The regularity estimate of solutions to source problems of the fractional Laplacian in arbitrary dimensions is firstly investigated in weighted Sobolev spaces.Then the regularity of eigenfunctions of the fractional Laplacian eigenvalue problem is readily derived.Meanwhile,rigorous error estimates of the eigenvalues and eigenvectors are ob-tained.Numerical experiments are presented to demonstrate the accuracy and efficiency and to validate the theoretical results.

发展人口神经科学中的规范化建模:量化脑智发展规律与个体分化特征的“显微镜”

揭示脑与心智个体差异的来源、规律及其科学机制是发展人口神经科学领域颇具吸引力的研究方向.个体差异的复杂性与当前研究方法的局限性是该领域方向的挑战所在,亟须发展在群体和个体层面建模个体差异的方法学框架,来量化脑智群体规律及其个体分化特征,实现一般科学规律与个体应用转化的科学衔接.规范化建模为此提供了一种方法学选择:基于代表性样本,使用分布式回归等方法,建立群体规律的统计模型,并在此基础上推演个体偏离规范化群体参照的程度,从而量化个体分化指标.这一方法学框架为发展人口神经科学提供了新工具,从人口生命周期的视角揭示了个体脑智差异的一般规律及其生物学基础,为解析脑智疾患的病因学机制及精准化临床实践提供了参考.鉴于规范化建模方法的巨大潜力,未来亟须在采样策略优化、数据收集规范以及建模方法改进等方面开展深入研究,从而加速其应用转化.

Multifaceted function of YAP/TEAD on chromatin:prospects of‘A non-canonical role of YAP/TEAD is required for activation of estrogen-regulated enhancers in breast cancer’

Cellular function and behavior are controlled by various signals during development and disease progression in mammals.It is important to understand how signals ultimately alter the function and structure of DNA regulatory elements,especially enhancers,causing the changes of gene expression patterns.On average,each mature human cell harbors at least^100000 enhancers,but only a small percent of them have the function to activate gene expression.For instance,only^12%–18%of ERα-bound enhancers are active enhancers.How enhancers become functionally active is critical for our overall understanding of enhancer biology and gene regulation.Enhancers are recognized by signaling-dependent DNA binding transcription factors(TFs),resulting in the recruitment of different enhancer activation components that allow distal enhancers to interact with their target promoters through chromatin looping(Plank and Dean,2014).Increasing evidence indicates that the recruitment and switching of enhancer components underlie enhancer activation and the deregulation in enhancer component or architecture profoundly alters signal-regulated transcriptional machineries,leading to developmental defects or diseases.

A Triangular Spectral Method for the Stokes Equations

A triangular spectral method for the Stokes equations is developed in this paper.The main contributions are two-fold:First of all,a spectral method using the rational approximation is constructed and analyzed for the Stokes equations in a triangular domain.The existence and uniqueness of the solution,together with an error estimate for the velocity,are proved.Secondly,a nodal basis is constructed for the efficient implementation of the method.These new basis functions enjoy the fully tensorial product property as in a tensor-produce domain.The new triangular spectral method makes it easy to treat more complex geometries in the classical spectral-element framework,allowing us to use arbitrary triangular and tetrahedral elements.

A Unstructured Nodal Spectral-Element Method for the Navier-Stokes Equations

An unstructured nodal spectral-elementmethod for theNavier-Stokes equations is developed in this paper.The method is based on a triangular and tetrahedral rational approximation and an easy-to-implement nodal basis which fully enjoys the tensorial product property.It allows arbitrary triangular and tetrahedralmesh,affording greater flexibility in handling complex domains while maintaining all essential features of the usual spectral-element method.The details of the implementation and some numerical examples are provided to validate the efficiency and flexibility of the proposed method.