Synthesis of visible light responsive ultrafine K_4Ce_2Nb_(10)O_(30) by a stearic acid method

K4Ce2Nb10O30 ultrafine powders were prepared by stearic acid method (SAM). The obtained products were analyzed by X-ray diffraction, transmission electron microscopy, energy dispersive X-ray spectrometry, scanning electron microscopy and UV-visible absorption spectra. XRD patterns revealed that K4Ce2Nb10O30 powders treated at 900 oC for 2 h presented tetragonal structure without the presence of deleterious phases. Furthermore, the K4Ce2Nb10O30 prepared by SAM had considerable activity under visible light irradiation.

Pitfalls of acid leaching method for determining organic and inorganic carbon contents in marine sediments

Organic and inorganic carbon contents of marine sediments are important to reconstruct marine productivity,global carbon cycle, and climate change. A proper method to separate and determine organic and inorganic carbons is thus of great necessity. Although the best method is still disputable, the acid leaching method is widely used in many laboratories because of its ease-of-use and high accuracy. The results of the elemental analysis of sediment trap samples reveal that organic and inorganic carbon contents cannot be obtained using the acid leaching method, causing an infinitely amplified error when the carbon content of the decarbonated sample is 12%±1% according to a mathematical derivation. Acid fumigation and gasometric methods are used for comparison, which indicates that other methods can avoid this problem in organic carbon analysis. For the first time, this study uncovers the pitfalls of the acid leaching method, which limits the implication in practical laboratory measurement, and recommends alternative solutions of organic/inorganic carbon determination in marine sediments.

Extraction Optimization of Polysaccharides from Rhizoma Polygonati by Response Surface Methodology and Content Determination

[Objectives]This study aimed to investigate the water extraction-alcohol precipitation technology and content determination method of polysaccharides in Rhizoma Polygonati.[Methods]Taking the content of polysaccharides in the extract as the indicator,the extraction process was optimized using single-factor tests and Box-Behnken Design.The content of polysaccharides extracted was determined by the anthrone-sulfuric acid method.Among the three factors in the test design,the solid/liquid ratio and extraction time had a significant effect(P<0.05,P<0.01),while the extraction temperature had no effect on the content of polysaccharides extracted(P>0.05).[Results]The optimal extraction process for polysaccharides in Rhizoma Polygonati was as follows:liquid/solid ratio 20∶1(mL/g),extraction time 2 h,and extraction temperature 85℃.Under the optimal extraction process,the content of polysaccharides in the extract reached 12.50%.[Conclusions]The extraction process optimized by response surface methodology for polysaccharides in Rhizoma Polygonati is reliable and has practical value,and can be used to guide production practices.

A METHOD OF SYNTHESIS OF PHENYL-LACTIC ACID AND SUBSTITUTED PHENYL LACTIC ACIDS

A method for the conversion of α-acetamido-β-substituted phenyl acrylic acid (αtβSPAA)into substituted phenyl lactic acid(SPLA)is described and an improved Clemmensen reduction reagent is used.

Synthesis of piezoelectric nanocrystalline PZT powder by stearic acid gel method

PZT nanocrystalline powder was prepared by a stearic acid gel method. Thecrystallization process from the precursor was monitored by infrared spectroscopy, differentialthermal analysis, and thermogravimetric analysis. The nano-sized PZT powder was characterized byX-ray diffraction and transmission electron microscopy. It shows that pure single-phase PZT powdercould be obtained at 450 deg C for 1 h, and the particle size is about 20 nm. With an increase inthe calcination temperature, the PZT crystallite size increased.

Effects of Varieties and Cooking Methods on Physical and Chemical Characteristics of Cooked Rice

To analyze the effect of different lowland rice varieties and different cooking methods on physical and chemical characteristics of cooked rice. A factorial randomized block design with two factors was used and each combination of the factors was repeated three times. The first factor was rice variety（Ciherang and Ciliwung） and the second factor was the cooking method（stovetop, boiling and steaming, and rice cooker）. Results showed that Ciherang and Ciliwung varieties were classified into slender grain rice type with yellowred color. The amylose content of Ciherang was classified as moderate, while the amylose content of Ciliwung classified as low. The most abundant amino acid contained in Ciherang and Ciliwung varieties was glutamic acid. Statistical analysis showed that cooking method had significant effects on texture, lightness, chroma, hue and moisture content of cooked rice. Rice cooked with liwet method had the lowest texture value, lowest lightness value, highest chroma value, and highest moisture content.

SIMULTANEOUS DETERMINATION OF MULTICOMPONENT IN MIXED ACIDS BY MATHEMATICAL METHOD

A new method for the determination of components in mixed acids has been developed.The mathematical model is obtained from samples of known composition and is then used to predict the concentrations of components in unknown sample.The practical utility of this method is demonstrated for simultaneous determination of two systems of ternary mixed acids and the results are satisfactory.

QUANTITATIVE ANALYSIS OF VERY WEAK ACID AND BASE BY pH-FIXED TITRATION METHOD

pH-fixed titration method for the determination of weak acids and bases has been studied in this paper.It is not necessary to know the ionization constant of weak acid or base and the concentration of titrant. This method had been applied to determine phenol,4-aminoantipyrine and glycine,whose ionization constants range from 10^(-10)to 10^(-12).The results were satisfactory.

A NEW METHOD FOR THE SYNTHESIS OF METHACRYLIC ACID FROM ISOBUTYRALDEHYDE

Isobutyraldehyde was used as starting material via three steps: oxidation, chlorination and dehydro-chlorination to yield methacrylic acid. The total yield of methacrylic acid is 49.7%.

Lithium extraction from hard rock lithium ores(spodumene,lepidolite,zinnwaldite,petalite):Technology,resources,environment and cost

Lithium production in China mainly depends on hard rock lithium ores,which has a defect in resources,environment,and economy compared with extracting lithium from brine.This paper focuses on the research progress of extracting lithium from spodumene,lepidolite,petalite,and zinnwaldite by acid,alkali,salt roasting,and chlorination methods,and analyzes the resource intensity,environmental impact,and production cost of industrial lithium extraction from spodumene and lepidolite.It is found that the sulfuric acid method has a high lithium recovery rate,but with a complicated process and high energy consumption;alkali and chlorination methods can directly react with lithium ores,reducing energy consumption,but need to optimize reaction conditions and safety of equipment and operation;the salt roasting method has large material flux and high energy consumption,so require adjustment of sulfate ratio to increase the lithium yield and reduce production cost.Compared with extracting lithium from brine,extracting lithium from ores,calcination,roasting,purity,and other processes consume more resources and energy;and its environmental impact mainly comes from the pollutants discharged by fossil energy,9.3-60.4 times that of lithium extracted from brine.The processing cost of lithium extraction from lepidolite by sulfate roasting method is higher than that from spodumene by sulfuric acid due to the consumption of high-value sulfate.However,the production costs of both are mainly affected by the price of lithium ores,which is less competitive than that of extracting lithium from brine.Thus,the process of extracting lithium from ores should develop appropriate technology,shorten the process flow,save resources and energy,and increase the recovery rate of related elements to reduce environmental impact and improve the added value of by-products and the economy of the process.

Low-temperature Denitration Mechanism of NH_(3)-SCR over Fe/AC Catalyst

To study the modification mechanism of activated carbon(AC)by Fe and the low-temperature NH_(3)-selective catalytic reduction(SCR)denitration mechanism of Fe/AC catalysts,Fe/AC catalysts were prepared using coconut shell AC activated by nitric acid as the support and iron oxide as the active component.The crystal structure,surface morphology,pore structure,functional groups and valence states of the active components of Fe/AC catalysts were characterised by X-ray diffraction,scanning electron microscopy,nitrogen adsorption and desorption,Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy,respectively.The effect of Fe loading and calcination temperature on the low-temperature denitration of NH_(3)-SCR over Fe/AC catalysts was studied using NH_(3)as the reducing gas at low temperature(150℃).The results show that the iron oxide on the Fe/AC catalyst is spherical and uniformly dispersed on the surface of AC,thereby improving the crystallisation performance and increasing the number of active sites and specific surface area on AC in contact with the reaction gas.Hence,a rapid NH_(3)-SCR reaction was realised.When the roasting temperature remains constant,the iron oxide crystals formed by increasing the amount of loading can enter the AC pore structure and accumulate to form more micropores.When the roasting temperature is raised from 400 to 500℃,the iron oxide is mainly transformed fromα-Fe_(2)O_(3)toγ-Fe_(2)O_(3),which improves the iron oxide dispersion and increases its denitration active site,allowing gas adsorption.When the Fe loading amount is 10%,and the roasting temperature is 500℃,the NO removal rate of the Fe/AC catalyst can reach 95%.According to the study,the low-temperature NH_(3)-SCR mechanism of Fe/AC catalyst is proposed,in which the redox reaction between Fe~(2+)and Fe~(3+)will facilitate the formation of reactive oxygen vacancies,which increases the amount of oxygen adsorption on the surface,especially the increase in surface acid sites,and promotes and adsorbs more reaction gases(NH_(3),O_(2),NO).The transformation from the standard SCR reaction to the fast SCR reaction is accelerated.

井冈霉素的提纯和含量测定研究(英文)

[ Objective ] In order to get the standard substance of Jinggangmycin used in quality control, Jinggangmycin was purified from its original pesticide and its content was determined, t Method] Mixed solvents were selected to recrystallize Jinggangmycin （content 62% ）. Phenol-sulfuric acid colofirnetric method was adopted to determine its content, and the effects of different determination conditions on the content results were also studied. E Result~ The purity of the samples after re-eryatallization was increased to 97.7%. The optimal conditions for phenol-sulfuric acid colorimetric method to determine the content of Jinggan^nyein were as follows： anhydrous glucose as control sample, 5% phenol, 1.0 ml phenol solution, 5.0 nfl sulfuric acid, stilly placed for20 min after reaction, 490 nm as detec- tion wavelength; the correlation coefficient of glucose standard curve （ R2 ） was 0. 993 9; the average recovery of standard addition was 99.72%, RSD was 0. 362 8%. ~ Conclusion] Re-cryatallization is a good way to refine Jinggan^nycin. Phenol-sulfuric acid colorimetric method can be used to determine the content of Jinggangmycin with simple operation, high accuracy and strong reliability, which can be widely applied in industrial production.

Synthesis and Structure Description of a New Tetradecaborate [H_3N(CH_2)_2NH_3]_2[B_(14)O_(20)(OH)_6]

A new tetradecaborate, [H3N（CH2）2NH3]2[B14O20（OH）6]（1）, was synthesized by a boric acid ＇flux＇ method, and characterized by X-ray powder diffraction, ICP, IR, TGA and DTA analyses. Single-crystal X-ray diffraction analysis showed that it crystallized in the monoclinic space group P1（No.2） with a=0.85092（10） nm, b=0.88678（11） nm, c=1.00724（13） nm, α=95.099（2）°, β=96.950（2）°, γ=116.845（2）°, V=0.66425（14） nm^3, Z=2, R1=0.0625[1〉2σ（I）], and WRE=0.1172（all data）. The molecule structure of compound 1 comprises the isolated polyanion clusters [B14O20（OH）6]^4- and diprotonated ethylenediamine molecules. Each polyanion cluster contains an 8-ring enclosed by six B3O3 3-ring units. Adjacent clusters are further connected with each other through strong hydrogen-bonding interactions of N（O）-H…O to form a three dimensional（3D） supramolecular structure with 2D pseudo channels along the [010] and [001] directions. The diprotonated ethylenediamine molecules located in the channels interact with the host through extensive hydrogen-bonds. Compound 1 presents few example containing isolated polyborate anions synthesized by a boric acid ＇flux＇ method.

Preparation and Characterisation of Sr2CeO_4:Eu^(3+) Rare Earth Luminescent Material by High Temperature Mechano-Chemical Method

A novel, high-temperature, mechano-chemical（HTMC） method was developed to synthesise singlephase Sr_2CeO_4：Eu^（3＋）phosphor. Phosphors were characterised by X-ray diffraction（XRD）, scanning electron microscopy（SEM）, and luminescence spectra. Compared with phosphors prepared by the traditional hightemperature solid state method and citric acid gel method, single-phase Sr_2CeO_4：Eu^（3＋）powders by using the HTMC method, with small average particle sizes of about 5 μm, a narrow size distribution range and uniform dispersion, were prepared at 800 ℃, and reached their maximum luminescent intensity at 900 ℃.Under ultraviolet excitation at 298 nm, the sample showed good luminescence with the strongest red light of 616 nm. However, Sr_2CeO_4：Eu^（3＋）was prepared at the higher temperature of 1100 ℃ by solid state method and citric acid gel method. The particle size was too large and uneven with phosphor agglomeration by high-temperature solid state method. The luminescent intensity reached a maximum for Sr_2CeO_4：Eu^（3＋）phosphor at a synthesis temperature of 1100 ℃ by using the high-temperature solid state method, and at 1200 ℃ by both citric acid gel and chemical precipitation methods. Furthermore, the advantages of the Sr_2CeO_4：Eu^（3＋）powder prepared by HTMC method were discussed compared with that prepared using traditional high-temperature solid state and citric acid gel methods.

Synthesis of rod-like ultrafine K_4Ce_2Nb_(10)O_(30) via a salt-assistant stearic acid method

A salt-assistant stearic acid method （SAM） capable of forming ultrafine K4Ce2Nb10O30 products was described. XRD pattern re-vealed that tetragonal K4Ce2Nb10O30 products could be obtained by heat treatment at 900 ℃ for 2 h. Transmission electron microscopy （TEM） observations indicated the introduction of KCl could lead to the formation of rod-like K4Ce2Nb10O30 products. The species of salts played a crucial role in fine tuning the shapes and sizes of K4Ce2Nb10O30 products. Furthermore, the K4Ce2Nb10O30 prepared by salt-assistant SAM had considerable activity under visible light irradiation.

The reaction of perfluoroalkanesulfinate——A novel method for the preparation ofperfluorocarboxylic acid and the coupling product perfluoroalkane

Oxidation of perfluoroalkanesulfinate usually resulted in the formation of the correspon-ding sulfonyl derivatives,thus reaction with hydrogen peroxide or halogen（Cl,Br,I）gavesulfonic acid or sulfonyl halides.However in comparison with alkanesulfinate the perfluo-ro analog was shown to be relatively inert toward oxidizing agents.

Synthesis and characterization of nano-sized YAG:Ce,Sm spherical phosphors

YAG：Ce,Sm spherical phosphors were synthesized by malic acid sol-gel method. The formation process of crystalline was characterized by X-ray diffraction （XRD） technique. The influence of Sm3＋ doping on the luminescent intensity and the morphology of phosphors were studied by fluorescence spectrum and scanning electron microscopy （SEM） techniques, respectively. The results indicated that the size of spherical powders was about 100 um calcined at 1200 ℃ for 3 h. The emission spectra of phosphors showed gradual red-shift from 525 to 540 um with the increase of doping concentration of Sm3＋ ion. A broadband emission specmtm of Ce3＋ ion appeared at 540 nm, and a series of emission peaks corresponding to the 4Gs/2-＋6Hd transition of Sm3＋ ion also appeared at 617 um with the doping of Sm3＋. The red component of YAG：Ce phosphors increased with the doping of Sm3＋.

Saponin Accumulation in Flower Buds of Panax notoginseng

Objective Panax notoginseng is an important Chinese medicinal plant. Saponin accumulation is higher in the flower buds than in the other parts of P. notoginseng. However, the flower bud compositions have not yet been quantified. The aim of this study is to investigate the formation and accumulation of saponins in the flower buds of P. notoginseng from different populations and at different growth years. Methods Fourteen types of P. notoginseng with different growing durations and from different areas of Wenshan County, Yunnan Province were collected. We separated P. notoginseng individually into the flower buds, stems, leaves, and roots at the places where it has the highest saponin content. An efficient high-performance liquid chromatography（HPLC） method was developed for simultaneously quantifying two active saponins, ginsenoside Rb1 and ginsenoside Rb3, in the flower buds of P. notoginseng. The total saponin content was determined by using a quantitative vanillin-sulfuric acid colorimetric method. HPLC method was used to establish the fingerprints of 13 saponins and then quantify the composition in the whole plant of P. notoginseng. Results The saponin contents of different parts differ significantly, and the total saponin content and those of Rb1 and Rb3 do not entirely correlated. The flower buds of P. notoginseng contain 27.79% of total saponins, which is the highest saponin content in the whole plant. Fingerprint result showed that different saponins were appeared in different parts of the plant, i.e. flower buds, stems, leaves, and roots.Conclusion The saponin contents from the flower buds of P. notoginseng vary depending on the growth area and duration. The fingerprints show that the saponin contents and compositions vary depending on the part of P. notoginseng. These results are useful for the pharmacological evaluation and quality control of P. notoginseng.

Acetalization of Carbonyl Compounds as Pentaerythritol Diacetals and Diketals in the Presence of Cellulose Sulfuric Acid as an Efficient, Biodegradable and Reusable Catalyst

This paper reports a practical and green method for the acetalization of carbonyl compounds as pentaerythritol diacetals and diketals derivatives using cellulose sulfuric acid as a biodegradable and reusable solid acid catalyst under thermal solvent-free conditions.