世界首棵人工合成树问世 可帮助研究压力下的水

美国每目科学网站9月11曰报道．在亚伯拉罕·斯特鲁克位于康奈尔的实验室中．世界上第一棵合成树静静地站在手掌大小的水凝胶中。

桦木硫酸盐木素的改性及树脂的合成研究

本文对桦木硫酸盐木素的改性及其在酚醛树脂中的应用进行了研究,结果发现,利用单因素法对木素硫改性进行分析时,其最佳条件为:硫用量5%,碱用量4%,最高温度260℃,保温时间15min.改性后木素甲氧基含量由原来的18.81%变为11.84%.利用改性及未改性木素取代苯酚合成木素酚醛树脂时,当两种木素分别取代60%的苯酚,使用桦木为单板时.其胶合强度虽然低于同样条件下酚醛树脂的胶合强度,但仍能达到国标要求、并且游离酚含量下降.另外,改性木素酚醛树脂胶合强度高于未改性木素酚醛树脂的强度,若再对改性木素合成本素酚醛树脂的条件进行优化,改性本素还有希望取代更大比例的苯酚.

一种子故障树的合成算法

以一种子故障树生成方法为基础,应用三维数组变换技术,提出了应用子故障树合成系统故障树的结构,依据顶事件及系统构成部件的特性推演故障树事件状态的子故障树合成算法。并结合一个复杂系统故障树的生成验证了该算法的可行性和有效性。

计算机辅助有机合成路线的设计

本文从计算机信息技术的角度分析了有机合成的基本推理过程、知识的描述和知识库的建立方法,以及有机物合成树的设计,并通过计算机技术对有机反应进行分类和比较,最终选出最佳的合成路线.

Bioinformatics Analysis of Chalconesynthase Gene in Morus

[Objective] This study aimed to explore the molecular mechanism of mulberry pigment metabolism regulation. [Method] Chalconesynthase（CHS） gene was cloned from Morus（Moraceae） in silico. The amino acid sequence, physical and chemical properties, transmembrane structural domain, hydrophobicity/hydrophilicity,subcellular localization, secondary and tertiary structure of protein were predicted and analyzed by bioinformatics tools. [Result] The cDNA sequence of CHS gene was 1 365bp by splicing using the software DNAstar and it contained a complete ORF including 1 170 bp which encoded 389 amino acids. Bioinformatic analysis showed that CHS gene included specific peptide sequence RLMMYQQGCFAGGTVLR of chalcone synthase superfamily, but has no signal peptide, belonging to the non-secretory proteins, located inside of cytoplasm. Its molecular evolution is more conservative.[Conclusion] The results above provided foundation for the further studies of structure and function of CHS protein.

现代汽车防滑装置简介

根据所使用的主体材料,现代汽车防滑装置可分为金属防滑链和非金属防滑装置两大类。一、金属防滑链图1所示的软梯状普通金属防滑链,系采用较粗的钢筋制造,其强度高,使用可靠,对于林区、矿山等条件恶劣的道路适应性很强。这种链的缺点是接触路面时有一股冲击力,对路面损伤大、噪音也大,所以不适于在城市及各种铺装路面上使用。

一种基于数据聚类的鲁棒SIFT特征匹配方法

针对噪声敏感造成的SIFT特征匹配鲁棒性低问题,提出一种基于数据聚类的两阶段特征匹配方法.在满足特征匹配几何距离最邻近本质要求下扩展了kd数据结构,使其不但能够完成算术平均化匹配特征离线聚类,而且能够实现第1阶段聚类特征在线匹配.在此基础上,给出一种概率最优投票策略选择关键图像进行第2阶段匹配,最后合并两阶段属于关键图像的所有匹配特征对.实验结果表明,对于大量存在重叠关系的图像集合,该方法能够有效减少重复特征数量,降低噪声信息对特征匹配的干扰,极大地提高特征匹配的鲁棒性.

A NEW ALGORITHM FOR ALL EFFICIENT SPANNING TREES

In Corley′s algorithm for all efficient spanning trees, final solutions include many spanning trees, which are not all efficient. In this paper, a new algorithm is presented, which corrects and modifies Corley′s algorithm. A necessary condition is developed for the subtree of an efficient spanning tree. According to the condition the new algorithm is established and its efficiency is proved.

Investigation on short-term burst pressure of plastic pipes reinforced by cross helically wound steel wires

Plastic pipes reinforced by cross helically wound steel wires (PSP), which have exhibited excellent mechanical performance, consist of inner polyethylene (PE) layer, winding layer and outer PE layer. The winding layer is composed of two monolayers where steel wires are cross helically wound. An analytical procedure is developed to predict the short-term burst pressure of PSP as the monolayer is assumed to be elastic and orthotropic. The 3D anisotropic elasticity and Maximum Stress Failure Criterion are employed in the formulation of the elasticity problem. Good agreement between the theoretical results and the experimental data shows that the proposed approach can well predict the short-term burst pressure of PSP.

Synthesis, Properties and Application of a Novel Epoxidized Soybean Oil-toughened Phenolic Resin

A novel epoxidized soybean oil-toughened-phenolic resin(ESO-T-PR)has been synthesized by etheri- fication graft and multi-amine curing ESO.Fourier transform infrared spectroscopy(FTIR)was adopted to investi- gate its molecular structure and scan electron microscope(SEM)was used to observe the micro morphology of its impact fracture surface.This ESO-T-PR was adopted as the matrix resin to prepare paper copper clad laminate (P-CCL)and the properties of resulting P-CCL are found superior to the related Chinese National Standard.The toughing mechanism was investigated by comparing the impact strength,solderleaching resistance,flexural strength, peeling strength and morphology of this ESO-T-PR with those of other two ESO modified phenolic resins.It is demonstrated that during the synthesizing process of ESO-T-PR,the phenol hydroxyl is etherified by ESO or ESO epoxy resin prepolymer(ESO chain extension polymer)and the long ESO epoxy resin chain segments enhance the crosslink density of ESO-T-PR and consequently improve the impact toughness and solderleaching resistance of P-CCL made of ESO-T-PR.The ESO-T-PR is a cheap matrix resin with excellent properties to make P-CCL(elec- tric guide board).

THE PREPARATION OF CROSSLINKED N,O-CARBOXYMETHYL CHITOSAN RESINSAND THEIR ADSORPTION PROPERTIESFOR TRIGLYCERIDE IN SERUM

Crosslinked N, O-carboxymethyl chitosan resins which can selectively adsorb triglyceride, were prepared by the reaction of N, O- carboxymethyl chitosan with glutaraldehyde solution. Adsorption experiments were performed by adding the resins to the serum. The results showed that this type of adsorbent could cut down the concentration of triglyceride in serum by 56. 4% (3. 35mg/gresin ) at most, while concentration of the total protein (TP ) decreased only by 10. 9% at least, so this novel adsorbent can be used to cure hypertriglyceridemia by hemoperfusion in the future.

Design Optimization of RFI Parameters by Manufacturing T-shaped Composite Panel

The aim of this project is to develop a novel approach for optimizing design resin film infusion (RFI) processing parameters by manufacturing T-shaped composite panel. The dimensional accuracy was selected as the objective function. By investigating the rheological properties of resin film, the compaction behavior of fiber preform and characteristics of RFI process, an optimal mathematical model was established, it was found that the numerical results obtained from the RFICOMP program package have good consistency with the experimental results, and this optimization procedure can be applied to other composites manufacture processes.

Optimization of Synthesis of Spherical Lignosulphonate Resin and Its Structure Characterization

Calcium lignosulphonate was used to synthesize a spherical lignosulphonate resin in a cheap and non-toxic disperse medium by reversed phase suspension polymerization. The process conditions were optimized by orthogonal experiments. Under .the optxmal conditxons （T=95 ℃, CHCl= 3 mol·L^-1, mHCHO： mCLS=7%, WCLS=50%）, globulation took about 20 min and the product was featured with excellent spherical shape, narrow particle size range, 61.20% of water retention capacity, 0.83 mmol·ml^- 1 of total volume exchange capacity and 3.46 mmol·g^- 1 of total exchange capacity. The results of Scanning Electron Micrograph and Scanning Probe Micrograph indicate that spherical lignosulphonate resin has a rugged surface with porous microstructure in the gel skeleton. The average pore size of dry samples was determined to be 10.46 nm. by the BET method.

Cloning and Analysis of a Chalone Synthase Gene from Fagopyrum tataricum

[Objective] This study aimed to clone a full-length CHS gene from buck- wheat. [Method] With total RNA extracted from buckwheat as the template, CHS cD- NA sequence was cloned from buckwheat by using RACE technology and CODEHOP primer design method, the full length gene was obtained by primers which were de- signed for amplification of full-length gene sequence with buckwheat DNA template. Clustalxl.81 and MEGA4 software were used for sequence analysis and construction of phylogenetic tree; NCBI Blastn and Biastp programs were applied for homology analysis of nucleic acid and protein. [Result] Bioinformatics analysis showed that the full length of this gene is 1 906 bp, containing a 463 bp intron sequence and a 1 188 bp coding region, encoding 395 amino acids. Blastn sequence alignment revealed that the CHS gene sequence obtained in this study shared 86% homology with the CHS gene of closely related species. [Conclusion] This study laid the foundation to clarify molecular basis of the synthesis of buckwheat bioflavanoids and explore an effective way to improve the content of buckwheat bioflavanoids.

Relationship between Microcellular Foaming Injection Molding Process Parameters and Cell Size

In order to study the relationship between the main process parameters and the cell size, the mathematical model of cell growth of microcellular foaming injection process is built. Then numeric simulation is employed as experimental method, and the Taguchi method is used to analyze significance of effect of process parameters on the cell size. At last the process parameters are focused on melt temperature, injection time, mold temperature and pretidied volume. The significance order from big to small of the effect of each process parameters on cell size is melt temperature, pre-filled volume, injection time, and mold temperature. On the basis of above research, the effect of each process parameter on cell size is further researched. Appropriate reduction of the melt temperature and increase of the pre-filled volume can optimize the cell size effectively, while the effects of injection time and mold temperature on cell size are less significant.

SYNTHESIS OF A NOVEL CHELATING RESIN WITH HETEROCYCLIC RING OF S AND N

By the reaction of poly(bromoacetyl styrene) (EBPS) with thiaurea (TU), a kind of novel chelating resin with heterocyaclic ring of sulfur and nitrogen, poly[4-(2-amino)thiazoleyl-4- vinylbenzene], was synthesized. Its structure was characterized by FTIR and elemental analysis. The factors which have influence on the reaction such as reaction time, solvents, and molar ratio of reactants were investigated.

Shear flow analyses for polymer melt extruding under superimposed vibration

The introduction of a vibration force field has a profound influence on the polymer formation process. However, its formation mechanism has not been explored until now. With the application of experimental equipment designed by the authors named “Constant Velocity Type Dynamic Rheometer of Capillary” or (CVDRC), we were able to analyze in detail the whole extrusion process of a polymer melt. We did this after superimposing a sine vibration of small amplitude parallel to the extruding direction of the polymer melt. Then, we created a calculation model to determine the shear stress at the wall of the capillary using a superimposed vibration. We also determined the calculation steps needed to establish the afore-mentioned shear stress. Through measurement and analysis, the instantaneous entry pressure of the capillary, the pressure gradient, and the shear stress of the polymer melt within the capillary under vibration force field can be calculated.

Tactical intention recognition of aerial target based on XGBoost decision tree

In order to improve the accuracy of target intent recognition,a recognition method based on XGBoost(eXtreme Gradient Boosting)decision tree is proposed.This paper adopts relevant data and program of python to calculate the probability of tactical intention.Then the sequence intention probability is obtained by applying Dempster-Shafer rule of combination.To verify the accuracy of recognition results,we compare the experimental results of this paper with the results in the literatures.The experiment shows that the probability of tactical intention recognition through this method is improved,so this method is feasible.

COMBINATORIAL SYNTHESIS OF MANNICH BASES IN SOLUTION/POLYMER REAGENT WORKUP

This paper describes a combinatorial Synthesis of the Mannich Bases in Solution through the Mannich reaction using 3 ketones, 5 amines and formaldehyde in solution and hydrochloride as a catalyst and then using a macroporous quarterized ammonium resin (CO32- form) as a scavenge agent to remove the acid catalyst when the Mannich reaction is completed. It was found by GC/MS analysis that the symmetrical ketone, such as acetone, in the Mannich reaction mainly produces one Mannich base; while the asymmetrical ketone, such as 2-pentanone, gives two Mannich bases. The reactivity depends on the tereo-hinder of both ketones and amines.

STUDY ON SYNTHESIS OF PVC SERIES OFMACROPOROUS SULFORIC RESINS AND THEIR APPLICATIONS IN CATALYTIC ESTERIFICATIONAND WATER TREATMENT

The PVC series of macroporous sulfonic cation-exchange resins were prepared by thesulfonation of a macroporous PVC bead with concentrated sulfonic acid or chlorosulfonicacid, the resulting sulfonic resin was employed in the investigation of catalyticesterification and softening of water The results show that the yields of esters reach60.0-84.4% according as different fatty acids and alcohols, the refractive indexes of estersobtained resemble those reported in the references basically, meanwhile, 345L softenedwaler which holds 0.06mmol/L hardness would be prepared by 1 L wet sulfonic resinreusing for 4 times. The resulting sulfonic resins would have 1.6-2.0 or 2.5-3.0mmol/gexchange capacity by using concentrated sulfonic acid or chlorosulfonic acid assulfonating agent, respectively The sulfonic resin has a macroporous structure taking themorphology with agglomerates of minutely spherical gel particles as characteristic.