RESEARCH ON THE WATER-RESISTANCE OF MAGNESIUM OXYCHLORIDE CEMENT——I:THE STABILITY OF THE REACTION PRODUCTS OF MAGNESIUM OXYCHLORIDE CEMENT IN WATER

In this paper .the change of the crystalline phases in hardened magnesium oxychloride cement (MOC) paste in mater was analyzed by XRD. It was developed that the reaction products 5 phase or 3 phase of MOC are instable in water and can be changed into Mg(OH)2 by the action of water, which causes the content of 5 phase or 3 phase to be less and less,the content of Mg(OH)2 to be more and more and the strength to be the lower the lower,after hardended MOC paste was immersed in water. The change of 5 pliase and 3 phase into Mg(OH)2 is not a dissolve process, but a hydrolysis process. The hydrolysis products of 5 phase and 3 phase are Mg(OH)2 precipitation and soluble Cl-,AIg+ ions and H2O. The hydrolysis is sponta-neous thermodynamically and its chemical kinatic equation is C = C,,e-k Thus .it is suggested that only by enhancing the stability of 5 phase or 3 phase in water and preventing 5 phase or 3 phase from the hydrolyzing can the water resistance of MOC be improved well.

Wettability of CuNi-Ti Alloys on Si_3N_4 and Interfacial Reaction Products

Based on the alloy Cu55Ni45 (at pct), holding the proportion of Cu to Ni in constant and in the temperature range of 1233~1573 K, the wetting angles of CuNi-0~56 at pct Ti alloys on Si3N4 have been measured by the sessile drop method. With the increase of Ti content, the wetting angles decreased. The equilibrium wetting angle was 5° when Ti content ≥32 at pct.In the case of same Ti content, the activity of Ti in CuNiTi alloy was weaker than that in CuTi alloy The cross-section of the CuNiTi-Si3N4 interface and the elements distribution were examined by scanning electron microscope with X-ray wave-dispersion spectrometer, and the reaction products formed at the interface were determined by X-ray diffiaction analysis method.

Reaction products of Sm_(2)Zr_(2)O_(7) with calcium-magnesium-aluminum-silicate(CMAS)and their evolution

During flight,many silicates(sand,dust,debris,fly ash,etc.)are ingested by an engine.They melt at high operating temperatures on the surface of thermal barrier coatings(TBCs)to form calcium-magnesium-aluminum-silicate(CMAS)amorphous settling.CMAS corrodes TBCs and causes many problems,such as composition segregation,degradation,cracking,and disbanding.As a new generation of TBC candidate materials,rare-earth zirconates(such as Sm_(2)Zr_(2)O_(7))have good CMAS resistance properties.The reaction products of Sm_(2)Zr_(2)O_(7) and CMAS and their subsequent changes were studied by the reaction of Sm_(2)Zr_(2)O_(7) and excess CMAS at 1350℃.After 1 h of reaction,Sm_(2)Zr_(2)O_(7) powders were not completely corroded.The reaction products were Sm-apatite and c-Zr0_(2) solid solution.After 4h of reaction,all Sm_(2)Zr_(2)O_(7) powders were completely corroded.After 24 h of reaction,Sm-apatite disappeared,and the c-Zr02 solid solution remained.

NATURAL PRODUCTS SYNTHESIS BY RETRO-DIELS-ALDER REACTION Ⅷ~1 A CONCISE STEREOSPECIFIC FORMAL SYNTHESIS OF TETRAHYDROCHLOROVULONE

A potent antineoplastic tetrahydrochlorovulone 3 was synthesized with retro-Diels Alder reaction as a key step.

Formation of Hybrid Ring Structure of Cyanurate/Isocyanurate in the Reaction be-tween 2,4,6-Tris(4-Phenyl-Phenoxy)-1, 3,5-Triazine and Phenyl Glycidyl Ether

Reaction products of 2,4,6-tris(4-phenyl-phenoxy)-1,3,5-triazine derived from 4-phenylphenol cyanate ester and phenyl glycidyl ether were analyzed. In addition to an isocyanurate compound and an oxazolidone compound which were well known as reaction products of cyanate esters and epoxy resins, compounds with hybrid ring structure of cyanurate/isocyanurate were determined. Gibbs free energies of the compound having hybrid ring structure of cyanurate/isocyanurate with two isocyanurate moiety were found to be lower than that of the compound with cyanurate ring structure through calculations. Calculation data supported the existence of hybrid ring structure of cy-anurate/isocyanurate. It was revealed that isomerization from cyanurate to isocyanurate occurs via hybrid ring structure of cyanurate/isocyanurate in the reaction of aryl cyanurate and epoxy.

Interfacial reaction product and mechanical properties of the electron beam brazed K465 Ni-based superalloy joints

Ni-based superalloy K465 is brazed with BNi-2 filler metal by vacuum electron beam brazing （VEBB）. In process of VEBB, effects of processing primary parameters on shear strength of joints are investigated. Microstructure of the brazed joint with BNi-2 filler metal is studied by means of scanning electron microscopy （ SEM）, energy dispersive spectroscopy （EDS） and X-ray diffraction （XRD）. The results show that the structure of brazed seam consists of a large amount of Ni- based γ solid solution, Ni3Al （ γ＇） , Ni3B, WB, CrB, and a small quantity of WC, NbC, The maximum shear strength of the joint is 398 MPa when the beam current of welding is 2.6 mA, heating time is 480 s and focused current is 1 800 mA.

THE THEORETICAL STUDIES OF PRODUCT ALIGNMENT OF THE REACTIONS OF Na,F WITH CH_3I

The NaI and IF product rotational alignment of the reactions of Na,F+CH_3I has been theoretically studied in a LEPS PES.The product alignment versus the relative translational energy of the reactants has been obtained.

Advanced glycation end product signaling and metabolic complications:Dietary approach

Advanced glycation end products(AGEs)are a heterogeneous collection of compounds formed during industrial processing and home cooking through a sequence of nonenzymatic glycation reactions.The modern western diet is full of heat-treated foods that contribute to AGE intake.Foods high in AGEs in the contemporary diet include processed cereal products.Due to industrialization and marketing strategies,restaurant meals are modified rather than being traditionally or conventionally cooked.Fried,grilled,baked,and boiled foods have the greatest AGE levels.Higher AGE-content foods include dry nuts,roasted walnuts,sunflower seeds,fried chicken,bacon,and beef.Animal proteins and processed plant foods contain furosine,acrylamide,heterocyclic amines,and 5-hydroxymethylfurfural.Furosine(2-furoil-methyl-lysine)is an amino acid found in cooked meat products and other processed foods.High concentrations of carboxymethyl-lysine,carboxyethyl-lysine,and methylglyoxal-O are found in heat-treated nonvegetarian foods,peanut butter,and cereal items.Increased plasma levels of AGEs,which are harmful chemicals that lead to age-related diseases and physiological aging,diabetes,and autoimmune/inflammatory rheumatic diseases such as systemic lupus erythematosus and rheumatoid arthritis.AGEs in the pathophysiology of metabolic diseases have been linked to individuals with diabetes mellitus who have peripheral nerves with high amounts of AGEs and diabetes has been linked to increased myelin glycation.Insulin resistance and hyperglycemia can impact numerous human tissues and organs,leading to long-term difficulties in a number of systems and organs,including the cardiovascular system.Plasma AGE levels are linked to all-cause mortality in individuals with diabetes who have fatal or nonfatal coronary artery disease,such as ventricular dysfunction.High levels of tissue AGEs are independently associated with cardiac systolic dysfunction in diabetic patients with heart failure compared with diabetic patients without heart failure.It is widely recognized that AGEs and oxidative stress play a key role in the cardiovascular complications of diabetes because they both influence and are impacted by oxidative stress.All chronic illnesses involve protein,lipid,or nucleic acid modifications including crosslinked and nondegradable aggregates known as AGEs.Endogenous AGE formation or dietary AGE uptake can result in additional protein modifications and stimulation of several inflammatory signaling pathways.Many of these systems,however,require additional explanation because they are not entirely obvious.This review summarizes the current evidence regarding dietary sources of AGEs and metabolism-related complications associated with AGEs.

Production of Superoxide Ion with Carbon Gas-Diffusion-Electrode And Reaction of Superoxide Ion with Aromatic Halide

Superoxide ion O^-_2 is prepared in aprotic media by carbon gas-diffusion-electrode for the first time. The experimental results indicate that this electrode is superior to carbon plane-electrode in the reaction of O^-_2 with p-bromonitrobenzene. When the gas-diffussion-electrode is used, the yield of the product nitrophenol increases by 20%, and the selectivity of the reaction is nearly doubled as compared with the plane-electrode.

Electrocatalytic Performance of Carbon Layer and Spherical Carbon/Carbon Cloth Composites Towards Hydrogen Evolution from the Direct Electrolysis of Bunsen Reaction Product

A composite material comprising a carbon layer and spherical carbon/carbon cloth(C-SC/CC)was fabricated using a hydrothermal-pyrolysis method,employing carbon cloth as the substrate and glucose as the carbon source.The C-SC/CC electrode was evaluated as an electrocatalytic electrode for hydrogen production by electrolysis of Bunsen reaction products.The electrode prepared with 4 g of glucose and annealed at 800°C showed excellent electrocatalytic activity.It requires only a potential of 185 mV(vs.SCE)to achieve a current density of 10 mA/cm2.Furthermore,the electrode demonstrated good stability with a 6%loss in current density after 1000 cycles of scanning from 0.2 V to 1.2 V.These results indicate the potential of the SC/CC electrode as an efficient and durable electrocatalyst for the electrolysis of H2SO4 and HI.

Risk assessment of chemical substances of safety concern generated in processed meats

This manuscript is reviewing the presence of substances of safety concern that may be generated in different types of meat products.Such substances include N-nitrosamines that can be generated under certain conditions when using nitrite as preservative,the polycyclic aromatic hydrocarbons generated as a consequence of particular smoking processes,heterocyclic aromatic amines generated under particular cooking conditions,compounds released from the oxidation of lipids and proteins,Maillard reaction products like acrylamide and carboxymethyl lysine,and amines that can be generated and accumulated in fermented meats.These hazardous compounds,their mechanisms of generation,risks for health and ways of preventing its presence in meat products are briefly described in this review.

Microstructure Characterization of Long W Core SiC Fiber

Microstructure of SiC fiber manufactured by chemical vapor deposition （CVD） onto tungsten （W） wire core was investigated by analytical electron microscopy （AEM）. The results reveal that the fiber consists of W core, SiC sheath and C-coating. SiC sheath could be subdivided into two parts according to whether containing C rich stripe, or not. An emphasis was put on W/SiC interfacial reaction products and the transition zone between sub-layers in SiC sheath. The W/SiC interface consists of three layers of reaction production, namely, W2C, W5Si3 and WC. And there are amounts of facet faults existing in （100） face of WC crystalline and two classes of stack faults in WC have been revealed. The formation essence of different sublayers in SiC sheath was also discussed.

Investigations on removal of SO_2 from flue gas by aerosol formation in pulsed corona discharge process

The removal of SO 2 from flue gas by pulsed corona discharge in presence of ammonia was experimentally investigated. The results showed that the SO 2 removal mainly depends on thermal reaction of SO 2 with NH 3 and enhancements of 0%—25% by pulsed corona discharge in the range of the specific energy 0—5 Wh/Nm 3. The aerosol mass concentration, mainly composed of ammonium sulfate, increased with specific energy dissipated into the reactor. With an initial concentration of 2000—2100 ppmv SO 2 and energy consumption of 3 Wh/Nm 3, when a stoichiometric amount of ammonia is injected, the removal efficiency of SO 2 and percentage of ammonium sulfates in reaction products are all ≥80%. The collection efficiency of the reactor for aerosol is about 74% at a flue gas temperature of 60 to 65℃ and a water vapor content of 9% to 11% volume.

Sequencing and Analysis of a 1500 bp HindIII-KpnI Fragment from LsNPV

The present work is concerned with the relationship of the different colors of NSE (non specific esterase) reaction product, in which alpha naphthyl acetate and diazotate of o dianisidine (Fast Blue B salt) were used as a substrate and a coupler respectively to describe the histochemical characteristics of NSE in chick embryonic mesonephros and metanephros. Our preliminary results throw light on the nature of NSE reaction produced colors, under light microscope, which were different in various sections for different air drying time length. The reaction product on the slices of the convoluted tubules of chick embryonic kidney was bright yellow after less than 30 min air drying time length, brown after 1.5～2 h air drying time length and black after more than 3 h of air drying. The color change process of NSE precipitates from bright yellow to black is progressive. The phenomennon has not been described previously.

Efficient and collective total synthesis of natural products via radical cascade reactions

Subject Code:B02With the support of the National Natural Science Foundation of China,the research team led by Prof.Qin Yong(秦勇)at Sichuan University accomplished a collective synthesis of 33 monoterpenoid indole alkaloids that belong to four families,by developing new photoredox-initiated radical cascade reactions.

The Influence of Aziridine on the Aging of Composite Solid Rocket Propellant

Aging of a solid composite propellant containing HTPB/AP/AL was performed in order to validate the conformance of the accelerated aging data to the Arrhenius law. The main objective of the work was to examine the influence of the aziridine bonding agents family on the propellant aging. Aging of the prepared propellant samples was conducted as follows: 1. Four samples, one free of bonding agents, and three containing aziridine based bonding agents MAPO,HX-752, MAT4 were aged at 65°C. 2. Another four samples based on HX-752, MAT4 with different curing agents were aged at 65°C. The measured mechanical properties of the free bonding agent propellant samples were very far from the specifications and this illustrates the importance of the bonding agents in both the preparation and the aging phases.The prepared bonding agent 'MAT4' gave remarkable improvements of the mechanical properties comparing with HX-752 and MAPO. The aziridine bonding agents family inhibited the rate of decomposition of the propellant during the aging periods and supported the propellant matrix against decomposition at the elevate temperatures. Using of HMDI as curing agent gave slight better mechanical properties to the IPDI.

ACTIVATION OF BOVINE FACTOR IX BY THE REACTION PRODUCT OF BOVINE FACTOR VII AND HUMAN TISSUE FACTOR

A study was carried out on the alternate activation of factor IX （FIX） by bovine FVII and human tissue factor （TF） rather than by activated factor XI （FXI）. The reaction product of bovine FVII and human TF functioned as a FIX activator in the assay system used. Published studies suggest that in the presence of Caions, the complex of human FVII-TF readily activates both human FIX and human FX,and at low TF concentrations, FIX appears to be the preferred substrate for the reaction product of FVII and TF. This may explain the discrepancy between the mild bleeding of hereditary FXI deficiency and the severe bleeding of hereditery FIX deficieney. The results obtained with bovine FVII and a crude human TF preparation confirm that at low TF concentrations,bovine FIX is the preferred substrate rather than FX. At higher TF concentrations, bovine FX was rapidly activated.

Extraction of resonance parameters from meson production reaction

We have developed an analytic continuation method for extracting parameters of nucleon resonances within a Hamiltonian formulation of meson-nucleon reactions. The method was tested for simple solvable models and then applied for our recent coupled channels model （πN, ηN, π△, ρN, and σN ） of the π＊N and γ＊N reactions. The resonance pole positions and their properties are studied for P11and P11 channels.

Cerium extraction by metallothermic reduction using cerium oxide powder injection

This work presented the feasibility of cerium recovery by Al-Mg alloy through the metallothermic reduction of CeO2 to obtain a master alloy Al-4%Ce. The master alloy obtained in this investigation was for the grain refinement and modification of Al-Si alloys. The reagent was incorporated into a molten alloy using the submerged powder injection technique, and metallic samples were obtained during injection. Chemical and microstructural analyses （by inductively coupled plasma （ICP） and scanning electron microscopy （SEM）, respectively） confirmed the possibility of Ce uptake in the bath （0 to 4 wt.%）, as CeO2 was reduced through metallothermic reactions in the molten alloys. Based on the characterization of reaction products, the sequence of the reaction was proposed.

Study of excited nucleon states at EBAC:status and plans

We present an overview of a research program for the excited nucleon states in Excited Baryon Analysis Center （EBAC） at Jefferson Lab. Current status of our analysis of the meson production reactions based on the unitary dynamical coupled-channels model is summarized, and the N＊ pole positions extracted from the constructed scattering amplitudes are presented. Our plans for future developments are also discussed.