ESIS序列自适应生成算法

在以扩展有限状态机 (EFSM)为模型描述的协议一致性测试系统中,为了提高可执行状态验证序列 (ESIS)的计算效率,提出一种ESIS序列自适应生成算法.新算法采用基于可执行分析树 (EAT)的可执行分析方法确保生成的ESIS序列的可执行性.引入变迁区分度因子和节点收敛度因子,计算EAT搜索树节点权重来评价当前搜索方向的正确性.利用EAT搜索树节点权重函数作为节点搜索引擎,根据当前已经搜索节点的权重自适应选择下一步搜索的目标节点,把ESIS序列自动生成问题转化为自适应搜索权重最大的EAT节点问题来解决.实验数据表明,与宽度优先可执行性分析方法相比,自适应算法具有更小的状态格局搜索空间.     

A photosensitive copolymer for UV-curable electrodeposition coatings

A series of photosensitive random copolymers (UPDHES) were prepared by introducing acrylate groups onto the side chain of the copolymer backbone of N, N-domethyl amimethyl methacrylate (DMAEMA), 2-hydroxypropyl acrylate (HEA), 2-ethylhexyl acrylate (EHA), and styrene (St) (PDHES). The molecular structure of UPDHES was characterized by FTIR, 1HNMR and GPC. The photopolymerization kinetics of UPDHES with different C=C content was investigated using real time FTIR in which it was found that the UPDHES system had notable photosensitivity. The effect of C=C content on the properties of cured films were studied by evaluating various film properties such as thermal stability, glass transition temperature and tensile properties. The thermal degradation of cured films was investigated via thermogravimetric analysis/infrared spectrometry (TGA-IR). Thus a series of UV-curable electrodeposition coatings with good photosensitivity and mechanical properties were prepared from a low-cost photosensitive random copolymer.     

EFSM可执行状态验证序列的生成

在以扩展有限状态机(EFSM)为模型描述的协议一致性测试系统中，为了解决状态验证序列的可执行性问题，提出了一种新的可执行状态验证序列(ESIS)生成算法。新算法基于宽度优先搜索可执行分析树(EAT)的思想，从状态验证需求的角度，在EFSM的状态格局投影子空间中，采用分步计算的方式生成具体验证场景下的最短可执行状态验证序列，从而减少了在完全状态格局空间中单步计算所有状态验证序列的复杂性。实验结果表明了新算法对生成EFSM可执行状态验证序列是有效的。     

球碳钕系催化丁二烯-异戊二烯共聚物的红外光谱测定

红外光谱法（ＦＴ ＩＲ）测定了（Ｃ６０Ｘ）载体钕系催化剂引发不同丁二烯 异戊二烯摩尔比所得共聚物的组成变化规律,提出了球碳９７３ｃｍ－１吸收带可能与共聚物主链上双键与Ｃ６０分子骨架间存在π π相互作用有关的解释。     

Alteration of diaspore by thermal treatment

Diaspore (α-AlOOH) was heated at various temperatures from 300 to 1000 ℃ for 2 h. The alteration of diaspore by thermal treatment was investigated by differential thermal analysis, thermogravimetric analysis and X-ray diffraction. The mechanism of thermal decomposition of diaspore was discussed according to the Coats-Redfern equation. It is found that after thermal treatment at 500 ℃, diaspore is transformed entirely to corundum (α-Al2O3). Combined with the mass loss ratio obtained from the thermogravimetric analysis data, the activation energies for the thermal treatment of diaspore are calculated as Ea=10.4 kJ/mol below 400 ℃ and Eb=47.5 kJ/mol above 400 ℃, respectively, which is directly related to the structural alteration of diaspore during the thermal treatment. The results indicate that the thermal decomposition of diaspore is conducted primarily by means of an interfacial reaction.     

Preparation of high molecular weight poly(L-lactide-co-caprolactone)(85-15)

Poly(L-lactide-co-caprolactone)(85-15)[P(LLA-CL)(85-15)] was synthesized from high purity L-lactide and ε-caprolactone using tin octoate as initiator by ring-opening polymerization, and characterized by infrared spectrum and 1H-NMR spectrum. The synthesized P(LLA-CL)(85-15) is a random copolymer. The influences of polymerization temperature, polymerization time, dosage of initiator and polymerization pressure on the weight average molecular weight and the polydispersity index of P(LLA-CL)(85-15) were investigated. The optimum preparation conditions of P(LLA-CL)(85-15) are: the polymerization pressure is less than 0.5 Pa, the polymerization temperature is 130 ℃, the n(M)/n(I) ratio is 8 000/1, and the polymerization time is 36 h. Under the condition, the weight-average molecular weight of prepared P(LLA-CL)(85-15) is 65.6×104, and molecular weight distribution coefficient is 1.15.     

Self-assembly of Ag-TiO2 nanoparticles: Synthesis, characterization and catalytic application

The formation of Ag clusters on titanium oxide (TiO2) nanoparticles was achieved by self-assembly process and calcination. The obtained nanoparticles were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and ultraviolet visible spectroscopy (UV-Vis), and conventional techniques (XRD, TEM and UV-Vis) were used to identify Ag particles on the TiO2 surfaces. The results show that Ag-TiO2 particles can be applied to improve catalytic activity of the epoxidation of styrene oxides. Styrene oxide is the main product of catalytic reaction with H2O2 as the oxidant by using Ag-TiO2 nanoparticles as catalysts. High catalytic activitity of styrene oxide can be obtainable at 80 ℃. The reaction temperature, reaction time, the molar ratio of H2O2/styrene and solvent affect greatly the catalytic epoxidation of styrene.     

Synthesis and characterization of hydroxylated fullerene epoxide—an intermediate for forming fullerol

A new C₆₀ derivative—hydroxylated fullerene epoxide [C₆₀ (OH) _x (O) _y ] was prepared by the reaction of C₆₀ benzene solution with aqueous NaOH and H₂O₂ in the presence of tetrabutylammonium hydroxide (TBAH) as the catalyzer. The structure of hydroxylated fullerene epoxide was characterized by FT-IR, NMR and MS, and it was found that it is easy to hydrolyze to fullerol. Project supported by the Nonferrous Metals Industrial Corporation of China Synopsis of the first author Li Tianbao, doctoral student, born in 1965, major in Fullerence Chemistry and Materials.     

负载型稀土催化体系催化合成聚异戊二烯的研究

以MgCl_2为载体,制备了一种新型负载型催化体系-NdCl_3·TBP/MgCl_2-Al(i-Bu)_3体系,探讨了该催化体系催化异戊二烯聚合的某些规律.结果表明,该体系对异戊二烯聚合具有较高的活性,以载钕量3%的催化活性为佳,所得聚合物的分子量较高,分子量分布窄,GPC曲线呈单峰分布,经IR和~(13)C-NMR联合测定表明,聚合物顺-1,4含量在95%左右.     

尼龙6的络合与解络合

为了用超高分子质量尼龙6制备高强高模纤维,对超高分子质量尼龙6分子间的酰胺基氢键的屏蔽和再生进行了研究. 以三氯化镓在硝基甲烷中络合超高分子质量尼龙6以屏蔽氢键,提高拉伸倍数;考察了水、氢氧化钠水溶液和乙醇对络合体系再生的效果;采用XRD、元素分析、DSC以及FTIR法对溶液体系和再生物进行了表征. 结果表明:采用上述方法可以制得无定型三氯化镓-硝基甲烷-超高分子质量尼龙6络合物,超高分子质量尼龙6分子间的氢键被屏蔽,络合物薄膜能拉伸到近20倍;上述3种解络合剂对络合物解络合得到的再生物可以恢复其常规尼龙6的结晶性能.     

Effect of reactive nanoclays on performances of PMMA/reactive nanoclay nanocomposites

PMMA/reactive nanoclay nanocomposites were prepared by emulsion polymerization using two different reactive nanoclays. X-ray diffraction (XRD) and thermogravimetric analysis (TGA) results confirmed that the reactive nanoclays, kaolinite and montmorillonite, were obtained by the silylation reaction and the double bonds were grafted onto the edges and surfaces of the nanoclays. The presence of reactive nanoclays could increase the average molecular weights, the glass transition temperatures (T _g) and improve the thermal properties of nanocomposite. The tensile properties, Young’s modulus, and the aging properties of the nanocomposite films were also enhanced while the light transmittance decreased. Furthermore, the nanocomposites with the reactive kaolinite presented better performances than that with the reactive montmorillonite. Finally, the action mechanism of the reactive nanoclays to the performances of PMMA/reactive nanoclay nanocomposites was proposed.     

ITA熔融接枝PP防降解研究

通过熔融接枝技术采用反应型双螺杆挤出机制备了可反应型相容剂,研究了衣康酸（ITA）含量、苯乙烯（St）含量、二甲苯（DMB）含量、过氧化二异丙苯/过氧化苯甲酰（DCP/BPO）复合引发体系及预处理工艺和工艺条件等对接枝物降解的影响。采用傅立叶红外光谱（FTIR）对接枝物结构进行了分析。结果表明：ITA和St接枝到了PP大分子链上,当PP/ITA/St/DCP/BPO/PEG=100/4/4/0.6/0.2/2时,接枝物性能最佳,GR和MFR分别为1.15%和3.5g/10min（纯PP为3.6g/10min）。     

异丙氧基稀土催化合成聚异戊二烯的活性

探索异戊二烯在三异丙氧基钕—三异丁基铝—卤代烷基铝三元催化体系作用下的一般聚合规律并对聚异戊二烯的分子量、分子量分布和微观结构进行了表征。本催化体系可获得分子量分布较宽,顺—1,4结构含量93%左右,其余为3,4结构的聚异戊二烯。实验证明:催化剂组分间的反应顺序以 A1+Nd+X的活性最高;较高温度下,催化剂高浓度陈化是提高其催化活性的方法之一,催化剂组分的配比以 X/Nd 为3左右,Al/Nd 约为50时活性最佳,显示出较高的催化活性。     

Synthesis and properties of UV curable polyurethane acrylates based on two different hydroxyethyl acrylates

Two kinds of UV curable polyurethane acrylate oligomers (PUPA and PUCA) were synthesized via the addition reaction between isophorone diisocyanate (IPDI) and polyethylene glycol monoacrylate (PEA₆) or polycaprolactone modified hydroxyethyl acrylate (PCLA₂). The structures of PUPA and PUCA were characterized by Fourier transform infrared spectroscopy (FT-IR), ¹H nuclear magnetic resonance (¹H NMR), gel permeation chromatography (GPC) and differential scanning calorimeter (DSC), and the thermal stability and dynamic mechanical thermal properties of their cured films were measured by thermogravimetric analysis (TGA) and dynamic mechanical analysis (DMA), respectively. The viscosity of the oligomers and mechanical properties of the cured films were also studied. The results show that both oligomers have narrow molecular weight distribution. The viscosity of PUPA is 2.310 Pa·s at 25 °C, while that of PUCA is up to 3.980 Pa·s. The UV cured PUPA and PUCA films have homogeneous phase structure, and the PUCA film shows higher glass transition temperature and storage modulus. Furthermore, the PUCA film possesses better mechanical properties than PUPA, while the latter shows better alkali resistance.     

Synthesis and Characterization of a Biodegradable Copolymer: RGD Peptide Modification of Poly (lactic acid-co-lysine)

1Introduction Theuseofsyntheticdegradablepolymersindrugde liverysystemshasdramaticallyexpandedinthepastde cade.Poly(glycolicacid),poly(lacticacid),andtheir copolymersaresyntheticpolyestersthathavebeenap provedbytheFDAforcertainusesandinvestigatedfor manya…     

Microstructure and deposition mechanism of C/SiCN composites prepared by rapid electro-thermal pyrolysis CVD

Carbon fiber-reinforced silicon carbonitride ceramic matrix composites (C/SiCN) were prepared by rapid electro-thermal pyrolysis CVD using liquid polymer hexamethyldisilazane (HMDS, (CH3)3SiNHSi(CH3)3) as precursor. Microstructure morphology and production technique of C/SiCN composites were investigated. Scanning electron microscopy and transmission electron microscopy were respectively employed to characterize microstructures of the as-received C/SiCN composites samples. The high temperature pyrolysis of HMDS results in destruction of molecular chain, fracture of bonds, as well as liquid-gas-solid conversion from polymer to ceramic. Microstructures observation indicates that there is a high degree of coalescence between SiCN matrix and C fiber. The deposition model of liquid precursor electro-thermal pyrolysis CVD is different from that of gas precursor isothermal chemical vapor infiltration. Rapid liquid flow and slow gas diffusion are key factors for the difference of two methods. Preparation of rapid electro-thermal pyrolysis CVD consists of four steps including liquid polymer infiltration, polymer pyrolysis, rapid deposition of pyrolyzed substances and rapid densification, respectively.     

Melt synthesis and characterization of poly(L-lactic acid) chain linked by multifunctional epoxy compound

High molecular weight(Mw) poly(L-lactic acid)s(PLLAs) were synthesized using multifunctional epoxy compound(Joncryl-ADR4370) as chain extender. The products were characterized by gel permeation chromatography(GPC) and spectroscopy(¹HNMR and FTIR). The results indicated that the Mw of PLLA increased with the increasing of the ratio of epoxy compound and the extending of reaction time. The highest M _w of PLLA reached 360 000 g/mol when the ratio of epoxy compound was 1.5 wt%. However, the reactants turned to cross-linking when the ratio of epoxy compound was over 1.5 wt%. Differential scanning calorimetry(DSC) measurements demonstrated that the glass transition(T _g) and melting temperatures(T _m ) of products increased slightly as the increase of the molecular weight. Analysis of the hydrolytic degradation in vitro showed that the branched PLLA possessed the quicker degradability than that of the linear PLLA.     

ARGET ATRP制备甲基丙烯酸短全氟酯共聚物及其性能

为了研究新型环保型单体甲基丙烯酸（N-甲基全氟己烷磺酰胺基）乙酯（C6SMA）的共聚规律和产物性能,用电子转移再生催化剂原子转移自由基聚合（ARGET ATRP）法制备C6SMA和甲基丙烯酸甲酯（MMA）的无规共聚物,测试共聚动力学,利用凝胶渗透色谱（GPC）、核磁共振（1H-NMR）和接触角法表征共聚物的结构等特性.结果表明,ARGET ATRP很好地调控C6SMA/MMA的共聚反应,实现共聚物分子量及其分布(PDI)的控制,共聚物组成未发生明显的漂移现象,均聚物及共聚物膜的静态接触角数据表明,可以通过共聚有效降低氟单体用量同时兼具良好的疏水疏油性能,共聚物中C6SMA的摩尔分数在19%即可超过聚四氟乙烯（PTFE）的疏水疏油性.     

苯乙烯-甲基丙烯酸甲酯共聚物的物理性能测试

对小试和中试所得的苯乙烯(ST)-甲基丙烯酸甲酯(MMA)共聚物珠粒进行了分子量、密度、粒度分布和单体残留量的测定,说明熟化温度将影响共聚物的物理性能,为进一步工业化提供了可靠的实验数据和理论依据.     

P(C_9-丙烯酸)两亲聚合物的研究

利用自由基共聚合成了 P( C9-丙烯酸 )两亲聚合物 ,对其性质进行初步研究 ,发现其 CMC值比小分子表面活性剂小得多 ;其水溶液对油有很大的包容能力 ;将其用于乳液聚合作唯一的乳化剂可制备异型颗粒 ,其粒经约为 50 0 nm的均分散乳液。并对此类两亲聚合物的作用机理进行了初步推测