A convenient and stereoselective synthesis of （Z）-allyl selenides via Sm/TMSCI system-promoted coupling of Baylis-Hillman adducts with diselenides

A simple and convenient procedure for stercoselective synthesis of （Z）-allyl selenides has been developed by a one-pot reaction of diselenides with Baylis-Hillman adducts in the presence of samarium metal-trimethylsilyl chloride under mild conditions. Presumably, the diselenides are cleaved by Sm/TMSCI system to form selemde anions, which then undergo SN2＇ substitution of Baylis-Hillman adducts to produce the （Z）-allyl selenides.     

Sm/TiCl4 （cat.） system-mediated intermolecular and intramolecular reductive coupling reactions of ketones with esters

Sm/TiCl4 system could well integrate the high reactivity of samarium（Ⅱ） and high deoxygenation capacity of low valent titanium within one system. In this paper, the intermolecular and intramolecular reductive coupling reactions of ketones with esters mediated by metallic samarium （Sm） and a catalytic amount of titanium tetrachloride （TiCl4） were successfully developed. A series of substituted ketones and cyclic β-keto-esters were prepared in moderate to good yields under reflux and neutral conditions.     

Finite Element Analysis of Reinforced Concrete Plate Impacted by Block

A new concept of structurally dissipating rock-shed （SDR） was developed by the lab of Tonello IC and LOCIE-ESIGEC （ France）. To decide the dimension of the plate used in SDR, an ANSYS model which could simulate the impact of rock in the centre of the plate was established by Fabien Delhomme. By using this model, some finite element analyses are carried out in the present paper. Firstly, a plate impacted by a block is numerically simulated, the numerical results obtained from different mesh sizes are compared and the accuracy of the finite element model is verified. Then, the dynamic response of the plate impacted at the boundary and in the medium part is computed. By analyzing the stress in rebar, the most dangerous region of impact of plate was found. For a rectangular plate, the most dangerous region is at the corner of the plate when a block drops in. Finally, the whole deformation process of the plate under dropping block was simulated and a simplified definition （ effect zone） to describe the deformation process in different positions of plate was given. From this study, it is found that the impact only affects heavily within the effect zone.     

Field demonstration of reduction of lead availability in soil and cabbage （Brassica Chinensis L.） contaminated by mining tailings using phosphorus fertilizers

A field demonstration of reduction of lead availability in a soil and cabbage （Brassica Chinensis L.） contaminated by mining tailings, located in Shaoxing, China was carried out to evaluate the effects of applications of phosphorus fertilizers on Pb fractionation and Pb phytoavailability in the soil. It was found that the addition of all three P fertilizers including single super phosphate （SSP）, phosphate rock （PR）, and calcium magnesium phosphate （CMP） significantly decreased the percentage of water-soluble and exchangeable （WE） soil Pb and then reduced the uptake of Pb, Cd, and Zn by the cabbage compared to the control （CK）. The results showed that the level of 300 g P/mE soil was the most cost-effective application rate of P fertilizers for reducing Pb availability at the first stage of remediation, and that at this P level, the effect of WE fraction of Pb in the soil decreased by three phosphorus fertilizers followed the order： CMP （79%）〉SSP （41%）〉PR （23%）; Effectiveness on the reduction of Pb uptake by cabbage was in the order： CMP （53%）〉SSP （41%）〉PR （30%）. Therefore our field trial demonstrated that it was effective and feasible to reduce Pb availability in soil and cabbage contaminated by mining tailings using P fertilizers in China and PR would be a most cost-effective amendment.     

Preparation of nano-TiO2 photocatalysts and their decomposition activity in phenol-contaminated water

ZiO2 was prepared by the hydrolyzation method in （NH4）2SO4-modified TiCl4 solution, and TiO2 photocatalysts were obtained by accelerating the precipitation of TiO2 powder in a high-temperature water bath. The photocatalysts were characterized by Brunauer-Emmett-Teller （BET）, X-ray diffraction （XRD）, Raman spectrum and UV-Vis （Ultraviolet-Visible） spectrometry techniques, and the photocatalytic activity in phenol-contaminated water was investigated. The results showed that photocatalysts calcined at 400 ℃ had a specific surface area of 138.2 m^2/g and an average particle size of 9 nm, and a significant increase in thermal stability of anatase phase. At the calcination temperature of 700 ~C, the crystal form of TiO2 started to change into rutile （anatase： 97%, rutile： 3%）. The activity of TiO2 photocatalysts prepared with （NH4）2SO4-modified TIC14 solution was markedly stronger than that without （NH4）2SOg-modified TIC14 solution. Maximal photocatalytic activity was observed at the mole ratio of Ti：（NH4）2SO4= 1：2, the water-bath temperature of 90℃ and the calcination temperature of 700 ℃.     

Musing on Xiangshan

I was really happy as I set my foot in Xiangshan Park.Birds were twittering and the sunwas shining bright on the trees.I t was difficult to find such a fine day in winter.As a student who was afflicted by a large amount ofhomework,I was tired of living in the city.     

Science Letters： Brain natriuretic peptide： A potential indicator of cardiomyogenesis after autologous mesenchymal stem cell transplantation？

We observed in a pilot study that there was a transient elevation of brain natriuretic peptide （BNP） level shortly after the transplantation in the patient with ischemic heart failure, which is unexplainable by the simultaneous increase of the cardiac output and six-minute walk distance. Similar findings were observed in the phase I trial. We postulated on the basis of the finding of Fukuda in vitro that this transient elevation of BNP level against the improvement of cardiac function and exercise capacity might indicate cardiomyogenesis in patients after mesenchymal stem cell transplantation. Further study is warranted to verify the hypothesis.     

Using sequential analysis procedures to rank the influencing factors of public work＇s quality

In order to improve the efficiency in management of public work projects, screening and controlling influencing factors affecting the quality of a public work project is essential. This study synthesized 9 influential categories including 91 factors related to quality management of public works in Taiwan using a sequential analysis procedure. According to the Borda-values of influencing factors obtained from a first stage questionnaire, the number of primary factors selected by the responsible entities and the design-supervisory entities were 44 and 45 respectively. A Fuzzy Analytic Hierarchy Process （FAHP） was used to prioritize and rank these factors. The top five factors ranked by the responsible entities were （1） introduction of the earned value analysis, （2） working efficiency, （3） environmental laws and regulations, （4） price-index fluctuation, and （5） on-site safety management. The top five factors ranked by the design-supervisory entities were （1） man power, （2） laws and regulations, （3） price-index fluctuation, （4） traffic conditions, and （5） faulty design.     

Removal of sulfamethoxazole by nanofiltration membrane

The retention of sulfamethoxazole （SMZ） by nanofiltration （NF） membranes is strongly influenced by the pH value of the solution. The retention of SMZ reaches its peak value when the solution pH rises above its PKa2 value as the compound transforms into a negatively charged species. Charge repulsion is the main mechanism involved in SMZ removal by NF membranes. In this study, the removal of SMZ by NF membranes, as a function of solution chemistry, was examined at pH 8.9 to investigate the effect of solution conditions on charge repulsion. The results show that the retention of negatively charged SMZ is relatively independent of SMZ concentration, and an increase in the ionic strength of the solution causes a relatively small reduction in retention. A small effect of humic acid （HA） on SMZ retention was noticed at pH 8.9, which can be explained by a small but insignificant improvement in the zeta potential of the membrane caused by HA at high pH values. However, it was found that SMZ concentration in the feed decreased significantly in solutions containing tannic acid （TA）. The Adams-Bohart model was applied to our experimental data and was found to be suitable for describing the initial part of the breakthrough curves. The adsorptive parameters of the membrane were determined.     

L^p-estimates on a ratio involving a Bessel process

INTRODUCTION Throughout this paper, we shall work with a filtered complete probability space (?,F,(Ft),P) sat-isfying the usual conditions. Let B=(Bt)t≥0 be a stan-dard Brownian motion with B0=0. Denote by ú the set of all non-negative real numbers. Recall that a diffusion process X starting at x≥0 is called the square of a Bessel process of dimension δ>0 if d X t = δd t 2 | X t |d Bt , X 0= x, (1) Clearly, this equation has a unique non-negative strong solution X, i.e., …     

Extreme value distributions of mixing two sequences with the same MDA

Suppose {Xi,i≥1} and {Yi, i≥1} are two independent sequences with distribution functions and , respectively. Zi,n is the combination of Xi and Yi with a probability for each I with 1≤ i≤n. The extreme value distribution GZ(x) of this particular triangular array of the i.i.d. Random variables Z1,n,… Z2,n, Zn,n is discussed. We found a new form of the extreme value distributions i)ΦAα1(x)Φα2 and ii) ψAα(x)ψα2(x)α1<α2), which are not max-stable. It occurs if FX and FY belong to the same MDA(Φ) or MDA(Ψ).     

A class of not max-stable extreme value distributions

The sequences {Zi,n, l≤i≤n}, n≥l have multi-nomial distribution among i.i.d. random variables {X1,i, i≥1}, {X2,i,u≥l }, …, {Xm,i, i≥1 }. The extreme value distribution Gz(x) of this particular triangular array of i.i.d, random variables Z1,n, Z2Zn,n is discussed in this paper. We found a new type of not max-stable extreme value distributions, i) Gz(x) = r-1∏i=1ФAiαi(x) × Фαr (x);ii) Gz (x) = r-1∏i=1ψAiαi (x) × ψαr (x); iii) Gz (x) = r-1∏i=1 ∧Ai (λix) × A(x), r≥2, 0＜α1≤α2≤…≤αr and λi∈ (0,1] for i, l≤i≤r-1 which occur if Fj, …, Fm belong to the same MDA.     

An Alternative Scoring Formula for Multiple-Choice and True-False Tests

Abstract

Scoring multipie-choice questions according to the simple scoring systems S₁ = R, where R is the number of correct answers, produces an upward bias in scores of poorer students as a result of guessing. The scoring formula conventionally used to adjust for guessing is S₂ R-W/(n-1), where W is the number of wrong answers and nis the number of choices per question. However, S₂ is based on the unrealistic assumption that on each question the student either knows the correct answer or guesses randomly. On the basis of a more realistic assumption an alternative scoring formula is derived, S₄ = [nR + (n-1)Q - Q²/R]/2(n-1), where Q is the number of questions. Compared to S₄, the conventional formula (S₂) has a downward bias for Q/n < R < Q and the simple formula (S₁) has a downward bias for Q/(n-2)<R<Q in addition to its upward bias for R<Q/(n-2).     

Fabrication of LaAlO<Subscript>3</Subscript> film by sol-gel process with corresponding inorganic

Well-cubic perovskite lanthanum aluminate (LaAlO₃) film on (110) silicon substrate was fabricated by sol-gel method with corresponding inorganic salts. Lanthanum acetate and aluminum acetate glacial acetic acid solutions were prepared via ligand exchange starting from lanthanum nitrate hexahydrate and aluminum nitrate hexahydrate after being refluxed. (CH₃CO)₂O removed nitrates and the crystallized H₂O completely, acetylacetone (AcAc) was partially bidentated with metallic ion of the metallic acetates and formed La(OAc)_3−x (AcAc) _x which were hydrolyzed into La(AcAc)_3−x(OH) _x by adding 10 ml 0.4% methyl cellulose (MCL) solution. The La(AcAc)_3−x (OH) _x , polymerizing and combining with MCL, formed the LaAlO₃ sol precursor with heteropolymeric structure and formed film easily. The epitaxial LaAlO₃ film on Si(110) substrate was crystallized after being annealed in thermal annealing furnace for 650–750 °C/30 min. The morphologies and microstructures were characterized. The refractive index of the LAO film was 1.942 to 2.007; the dielectric constant and the dissipation factors were estimated to be 23–26 and 2.1×10⁻⁴−2.4×10⁻⁴ respectively. Project (No. 2002CB613305) supported by the National Basic Research Program (973) of China     

Molecular cloning and nucleotides sequence analysis of G1 genome segment of hantaan virus Z10 strain

The molecular cloning of the G₁ genome segment of the Z₁₀ strain of Hantaan virus and analysis of the first gene data on the currently widely used Hantavirus vaccine strain in China are presented. The G₁ genome segment of Z₁₀ virus was amplified by the method of RT-PCR, and the products were cloned into the pGEM-T vector after identification and purification. The clone was sequenced by Sanger’s dideoxy chain termination method. The 1449 bases of the Z₁₀ G₁ genome segment, and the coding for 483 amino acids were determined. The base compositions for the G₁ segment RNA determined from cDNA sequence information, were 20.6% A, 21.6% G, 18.8% C and 30.0% U. These values are similar to those of the 76/118, Lee and SR virus. As compared to the Z₁₀ G₁ segment, the sequence homology at the nucleotide level is 87% (76/118, type I), 86% (Lee, type I), 86% (Hojo, type I), 67% (R22, type II), and 59% (K22, type III). The Z₁₀ virus G₁ protein amino acid sequence identity with other Hantaan viruses (94–95% homology) was higher than that with Seoul type viruses (77–80%). More amino acid sequence heterogeneity between the Z₁₀ and 76/118 was observed in the N terminal, especially the diverging cluster of ten amino acids at position 84 to 93 of the Z₁₀ virus G₁ protein. Conclusion: (1) The Z₁₀ strain is one of the Hantaan viruses. (2) The important region of the Z₁₀ G₁ segment was conservative. (3) Although substantial divergence of nucleotide sequences of the G₁ genome segment was found between the Z₁₀ strain and other type I Hantaviruses, relatively high amino acid sequence homology was shown among them. Thus, good immune protection could be obtained with the inactivated Meriones unguiculatus kidney cell vaccine against other strains of Hantaviruses.     

自由群在有理数集上的表示

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Random quadralinear forms and schur product on tensors

In this work, we made progress on the problem that lr(○×)lp(○×)lq is a Banach algebra under schur product. Our results extend Tonge's results. We also obtained estimates for the norm of the random quadralinear form A:lMr×lNp×lKq×lHs→ C, defined by: A(ei, ej, ek, es)=aijks, where the (aijks)'s are uniformly bounded, independent, mean zero random variables. We proved that under some conditions lr(○×)lp(○×)lq (○×)ls is not a Banach algebra under schur product.