Initial Value Problem of Singular n-Laplacian Equation

To show some theorems on the existence of singular initial value problem with n Laplacian operator, topology method and methods of analysis are employed. Some existence theorems for initial value problems with n Laplacian operators are established in three singular cases.

异丁烷循环促进离子液体[Et_(3)NH]Cl-AlCl_(3)催化正庚烷异构化反应

轻烃异构化一般以C_(5)和C_(6)烃为原料,C_(7)及C_(7)以上烃类在异构化过程中由于存在较为剧烈的裂化反应,致使异构化油收率较低。作为一种新型低温轻烃异构化催化剂,离子液体对大分子烃类原料的适应性不佳。因此,在大分子烃类异构化过程中,抑制副反应、提高异构化油收率一直是研究的难点和重点。基于离子液体催化烷烃异构化反应机理,通过异丁烷循环抑制副反应、促进异构化反应的进行,进而降低异构化产物中C_(4)烷烃的含量,提高异构化油的收率。系统考察了异丁烷引入量、反应温度、反应时间、搅拌速率以及酸烃比等工艺条件对氯铝酸离子液体催化正庚烷异构化反应的影响规律。结果表明,体系中大量异丁烷的循环提高了氢转移速率,抑制了裂化、歧化等副反应,使副产物C 4组分的含量大幅降低。在异丁烷引入量为正庚烷体积的30%、反应温度为50℃、反应时间为1 h、搅拌速率为1500 r min和酸烃比(离子液体与正庚烷体积比)为1的条件下,正庚烷转化率达到91.0%,异构烷烃选择性和液体收率分别达到87.2%和93.5%;与未引入异丁烷体系相比,正庚烷转化率相近时,引入异丁烷体系的异构烷烃选择性和液体收率分别提高了16.0百分点和14.8百分点。

Analysis Approach to Durability Based on Material Initial Fatigue Quality and S-N Curve

Based on probabilistic fracture mechanics approach, a new concept of material initial fatigue quality （MIFQ） is developed. Then, the relation between S-N curve and crack propagation curve is studied. From the study, a new durability analysis method is presented. In this method, S-N curve is used to determine crack growth rate under constant amplitude loading and evaluate the effects of different factors on durability and then the structural durability is analyzed. The tests and analyses indicate that this method has lower dependence on testing, and higher accuracy, reliability and generality and is convenient for application.

Initial Rifting Age of the Nearly N–S Rifts in Southern Tibetan Plateau:New Evidence from the Age limit of the Early Sediments

Objective The nearly parallel N-S-trending rifts in southern Tibet represent the E-W extension of the Tibet Plateau. Most data which constrained the age of the extensional deformation come from isotopic dating of the dikes probably related to the activity of the nearly N-S faulting and micas from hydrothermal activity and the low- temperature thermochronology of plateau uplift. Previous research shows that there are at least three different ideas about the age of the rifts： （1） older than 16-12 Ma, （2） 14- 10 Ma, and （3） 8-4 Ma （Fig. la）. For the old sedimentary strata represented the beginning of the rifting, the dating of the sediments helps to better define the initial rifting age.

真核翻译起始因子4γ2调控N-乙酰氨基半乳糖转移酶1 mRNA对胃癌细胞恶性表型的影响

目的探讨真核翻译起始因子4γ2(EIF4G2)通过调控N-乙酰氨基半乳糖转移酶1(GALNT1)mRNA对胃癌进展的影响。方法通过生物信息数据库分析GALNT1、EIF4G2在胃癌细胞和胃癌组织中的表达及与胃癌患者预后的关系,并分析胃癌组织中EIF4G2、GALNT1表达的相关性。采用实时荧光定量聚合酶链反应(RT-qPCR)检测GALNT1 mRNA、EIF4G2 mRNA在人胃黏膜上皮细胞GES-1和人胃癌细胞(AGS细胞等)中的表达水平,并采用蛋白质印迹法(Western blot)检测GALNT1、EIF4G2蛋白表达水平。建立干扰GALNT1和过表达EIF4G2的AGS细胞株,采用CCK-8法和克隆形成实验检测细胞增殖能力,采用TUNEL实验检测细胞凋亡能力,采用划痕实验和Transwell实验分别检测细胞迁移和侵袭能力,采用Western blot检测凋亡和转移相关蛋白表达水平,采用RIP实验和RNA下拉实验检测GALNT1 mRNA与EIF4G2的结合关系。结果胃癌组织和胃癌细胞中的GALNT1、EIF4G2水平分别高于正常组织和人胃黏膜上皮细胞,差异有统计学意义(P<0.001),且与胃癌患者预后差相关;胃癌组织中,EIF4G2表达与GALNT1表达呈正相关。敲低GALNT1后,AGS细胞活力降低,克隆形成数、迁移和侵袭细胞数减少,凋亡细胞数增加,Bcl-2、MMP2、MMP9蛋白表达降低,Bax、cleaved-caspase3、cleaved-caspase9蛋白表达增加,差异有统计学意义(P<0.001)。EIF4G2可与GALNT1 mRNA结合,促进GALNT1 mRNA、GALNT1蛋白表达及GALNT1 mRNA稳定性,差异有统计学意义(P<0.001)。共转染sh-GALNT1-1与oe-EIF4G2可逆转sh-GALNT1-1对AGS细胞增殖、凋亡、迁移和侵袭的作用,差异有统计学意义(P<0.05或P<0.01或P<0.001)。结论EIF4G2可通过稳定GALNT1 mRNA促进胃癌细胞增殖、迁移、侵袭并抑制细胞凋亡,其或可成为胃癌临床诊疗的新靶点。

C_(4)F_(7)N/CO_(2)/O_(2)混合气体局部放电起始电压的试验研究

研究C_(4)F_(7)N/CO_(2)/O_(2)环保绝缘气体的局部放电特性,可为环保型气体绝缘电气设备的设计制造及运维提供技术支撑。为此,利用针–板电极研究了极不均匀电场中C_(4)F_(7)N/CO_(2)/O_(2)混合气体的交流局部放电起始电压(partial discharge initial voltage,PDIV),并分析了O_(2)的体积分数、气压以及电场不均匀系数对其PDIV的影响。试验结果表明:在0.15~0.25 MPa气压范围内,C_(4)F_(7)N/CO_(2)混合气体中加入O_(2)体积分数不宜超过4%;而在0.35~0.65 MPa气压范围内,3种O_(2)占比中,在C_(4)F_(7)N/CO_(2)混合气体加入体积分数为4%的O_(2)的方案相对最优。混合气体的PDIV随气压的变化会出现“驼峰效应”;O_(2)体积分数小于8%时,不均匀系数的增加能够有效减少C_(4)F_(7)N/CO_(2)/O_(2)和C_(4)F_(7)N/CO_(2)这2种混合气体PDIV幅值的差别;而O_(2)体积分数高于8%时,不均匀系数的变化对2种混合气体幅值差别的改变影响很小。因此,从混合气体交流局部放电起始电压角度考虑,C_(4)F_(7)N/CO_(2)/O_(2)混合气体具备应用于气体绝缘交流设备的可行性。

STUDIES ON THE INITIATION MECHANISM OF ORGANIC PEROXIDE AND N-METHACRYLOYLOXYETHYL-N-METHYL ANILINE IN METHYL METHACRYLATE POLYMERIZATION

The initiation mechanism of methyl methacrylate (MMA) polymerization by organic peroxide and polymerizable aromatic tertiary amine such as N-methacryloyloxyethyl-N-methyl aniline (MEMA) binary system has been studied. The kinetics of polymerization of MMA and the ESR spectra of organic peroxide/MEMA system were determined. Based on the ESR study and the end-group analysis by UV spectra of the polymer formed, the initiation mechanism is proposed.

VINYL RADICAL POLYMERIZATION INITIATED WITH CERIC ION AND ETHYL N, N-DIETHYLDITHIOCARBAMYL ACETATE SYSTEM

Acrylamide polymerization initiated with a redox initiation system consisting of eerie ion and ethyl N,N-diethyldithiocarbamyl acetate (EDCA) has been studied. It was found that the polymerization rate equation is in good agreement with that of a redox initiated polymerization, and the overall activation energy of the polymerization was determined to be 25.2 kJ.mol(-1). Accordingly, the system belongs to a redox initiator. The initiation mechanism was proposed based on the end group analysis using FT-IR, UV spectroscopies. Analysis results revealed that the N, N-diethyldithiocarbamyl radical produced from the redox reaction of EDCA with eerie ion can initiate acrylonitrile (AN) polymerization and form the end group on PAN. The resulting PAN was photopolymerized with butyl acrylate (BE) to form PAN-b-PBA block copolymer.

VINYL MONOMERS BEARING CHROMOPHORE MOIETIES AND THEIR POLYMERS——Ⅹ.INITIATION AND PHOTOCHEMICAL PROPERTIES OF p-(N,N-DIMETHYLAMINO)STYRENE AND ITS POLYMERS

A vinyl monomer having an electron-donating moiety, p-(N,N-dimethylamino)styrenc (DMAS),was synthesized. It was combined with benzoyl peroxide (BPO) to form a redox initiation system to initiatethe polymerization of methyl methacrylate (MMA). UV spectra measurements show that DMAS enters thePMMA chain as well. Both DMAS and its polymer P(DMAS) display strong fluorescence, and thefluorescence can be quenched by electron-deficient compounds such as methacrylonitrile, fumaronitrile andmethyl methacrylate etc. Moreover, DMAS can also form charge transfer complex (CTC) with strongelectron acceptors such as tetracyanoethylene (TCNE). The difference between the photochemical propertiesof DMAS and P(DMAS) were explained in terms of molecular structure change and polymer conformationeffect in solution. In addition, the CTC and exciplex formation of DMAS or P(DMAS) with C_(60) were alsostudied.

优化MGM(1,n)模型在边坡沉降预测中的应用研究

为更好地预测边坡沉降,考虑边坡整体变化趋势,采用多变量的优化MGM(1,n)模型,对边坡相关的各监测点的沉降变形进行了预测。该研究先以平均相对残差为指标筛选初值,引入背景值系数重构背景值计算公式;再据此建立改进的双值MGM(1,n)优化模型;最后,以中山西环高速公路A段的边坡工程为实例,分别建立传统MGM(1,n)模型、GM(1,1)模型和优化MGM(1,n)模型,并对所测数据进行建模预测和比较分析。研究结果表明:在3种优化模型中,优化MGM(1,n)模型的预测精度最高。该模型在边坡沉降预测方面具有一定的应用前景,可为类似工程和研究提供参考。

VINYL RADICAL POLYMERIZATION INITIATED WITH CERIC ION AND N-(SUBSTITUTED PHENYL) ACETAMIDE SYSTEMS

The polymerization of acrylamide (AAM)in H_2O/DMF or in H_2O/CH_3CN mixed solvent initiated with ceric ion (Ce^(4+) )/N-(substituted phenyl)-acetamide systems have been studied. The redox polymerization was revealed by the low value of overall activation energy (E_α) of AAM polymerization using ceric ion/N-(substituted phenyl) acetamide system as an initiator. The end group of polymer formed was detected by IR spectrum analysis method, it revealed the presence of N-(m-acetoxy-methylphenyl) acetamide (m-AAe) moiety end group in the polymer obtained with ceric ion/m-AAe initiation system.

Fatigue behavior and life prediction of A7N01 aluminium alloy welded joint

Fatigue characteristics of A7N01 aluminium alloy welded joint were investigated and a fatigue crack initiation life-based model was proposed. The difference of fatigue crack initiation life among base metal, weld metal and heat affected zone (HAZ) is slight. Furthermore, the ratio of fatigue crack initiation life (Ni) to fatigue life to failure(Nf) is a material dependent parameter, 26.32%, 40.21% and 60.67% for base metal, HAZ and weld metal, respectively. Total fatigue life predicted using the presented model is in good agreement with the experimental data and that using Basquin’s model. The observation results of fatigue fracture surfaces, using scanning electron microscope (SEM), demonstrate that fatigue crack initiates from smooth surface due to welding process for weld metal, blowhole in HAZ causes fatigue crack initiation, and the crushed second phase particles play an important part in fatigue crack initiation in base metal.

声学特征与普通话辅音声母的感知混淆

针对不同信噪比条件下广州话与普通话母语者对普通话辅音声母的感知混淆,在重点探讨辅音声学特征与感知混淆关系的基础上兼论母语背景和信噪比对普通话辅音声母感知结果的影响。使用混淆矩阵方法,要求13名广州话被试和22名普通话被试对经不同信噪比处理的辅元结构语音刺激中的辅音进行辨认。重复测量方差分析的结果表明,两组母语不同的被试对普通话辅音的感知能力有显著差异,且白噪声会降低两组被试的感知能力。共同的感知结果如下:(1)响辅音具有较好的抗噪性;(2)具有突出频谱峰的擦音和频谱较为平坦的擦音之间不容易发生感知混淆;(3)白噪声对过渡音征以及塞音除阻脉冲的掩蔽作用增加了不送气塞音之间的感知混淆以及送气塞音和送气塞擦音与擦音之间感知混淆;(4)后接元音的舌位对辅音感知混淆结果有一定程度的影响。以上结果表明,发音生理层面(或语言学理论层面)发音部位、发音方法和清浊的分类并不能完全预测噪声背景下普通话辅音声母的感知混淆现象,而使用频谱和音长等声学参数可以更好地解释感知混淆的结果,声学特征对辅音感知混淆的作用有时会超越音系的作用。

N-溴代丁二酰亚胺在有机反应中的应用进展

N-溴代丁二酰亚胺(NBS)是有机反应中常用的试剂,近几年来在多种有机反应中的应用都有了新的研究进展．综述了其作为反应过程中的催化剂、氧化剂、选择性溴代试剂以及聚合反应引发剂等方面最新的研究成果．

N-丙烯酰吗啉在可聚合叔胺-过硫酸钾水溶性引发体系引发下的水溶液聚合

本文报道了以甲基丙烯酸－N，N－甲氨基乙酯（DMAEMA）与过硫酸盐体系以引发的丙烯酰吗啉（AMP）的水溶液聚合，得到下列方程：Rp［K2S2O8］0．46［DMAEMA］0．49［AMP］1．09；Ea＝30．21KJ／mol。试用四氯乙烯（TCNE）处理的丙烯酸吗啉聚合物P（AMP）的紫外光谱分析，发现DMAEMA不仅参与引发AMP聚合，而且还进入P（AMP）分子链中。P（AMP）分子量比聚丙烯酰腹P（AAm）的小，而且随AMP（DMAEMA或温度）增加而增加（降低）。P（AMP）及其轻度交联的水凝胶表现出热敏性。

N－甲基丙烯酰－N＇－嘧啶哌嗪与过硫酸钾引发体系引发的丙烯酰胺聚合

Ｎ－甲基丙烯酰－Ｎ＇－嘧啶哌嗪与过硫酸钾引发体系引发的丙烯酰胺聚合高青雨，张福莲，杨更须，张举贤（河南大学化学化工系，开封，４７５００１）李福绵（北京大学化学系，北京，１０００８７１）关键词Ｎ－甲基丙烯酰－Ｎ＇－嘧啶哌嗪，可聚合芳香叔胺，氧化还原引发...

辅音/n/和/l/异常语音的特点及其治疗

目的:了解功能性语音障碍辅音/n/、/l/异常的发音特点及对语音清晰度的影响,探讨异常语音的治疗方法。方法:采用主观判听和语音检测方式对16例发/n/、/l/辅音及与之相关的单字、词组、句子发音异常的患者进行汉语语音学、语音病理学分析研究,采用以汉语发音为基础的矫治训练方法对16例患者进行系统的语音训练治疗,并对治疗前后的语音清晰度及辅音清晰度比较进行统计学处理。结果:患者治疗前后的语音清晰度由治疗前的75.8%,提高到治疗后的98.8%。与/n/、/l/有关的辅音清晰度从治疗前的45%提高到98.1%,语音治疗效果良好。结论:系统语音治疗可有效矫正辅音/n/、/l/发音异常的不良习惯,建立正确的发音模式,提高语音清晰度。

基于M/N逻辑和一步延迟的航迹起始方法

研究基于M/N逻辑和基于一步延迟的航迹起始方法,结合两者提出一种新的航迹起始方法。对落入相关区域中的量测加强约束条件,使每一个测量只能在一条航迹中出现;将相邻2个周期的权值与阈值进行比较,减少杂波对起始性能的影响。仿真结果表明,该方法在保证低虚假航迹概率的情况下,能正确起始航迹,缩短航迹起始时间,适用于密集杂波环境下的多目标航迹起始。

N取代丙烯酰胺的等离子体引发聚合及聚合物性能研究

通过等离子体引发溶液聚合的方法制备了 N ,N -二甲基丙烯酰胺 ( DMAA)和 N ,N -二乙基丙烯酰胺 ( DEAA)聚合物 PDMAA和 PDEAA.实验结果表明 ,对 DMAA及 DEAA,转化率随后聚合时间、放电时间延长而增大 ,单体质量分数以 5 0 %为佳 ;对 DEAA转化率随放电功率的增大而增加 ,而对 DMAA转化率以 1 5 0 W为佳 .对 PDMAA的吸水率 ,后聚合时间以 4 h为佳 ,放电时间延长吸水率下降 ,而放电功率对吸水率的影响不大 ;对 PDEAA的吸水率 ,后聚合时间以 8d为佳 ,放电时间延长、放电功率增加吸水率下降 .同时对所得的聚合物的吸水率和温度的关系作了考察 ,结果发现 PDMAA具有最高临界共溶温度区域为 2 0～30℃ ,而 PDEAA则具有最低临界共溶温度为 31℃ ,而且它们的最高吸水率达一百多倍 ,是传统方法制备的同类聚合物的吸水率的 4～ 1 0倍 .

有机过氧化物与N-甲基-N-2-羟乙基苯胺引发体系的研究

测定了有机过氧化物与N-甲基-N-2-羟乙基苯胺(HMA)体系引发MMA聚合的动力学方程和聚合表现活化能。由过氧化物/HMA/MNP的ESR波谱证实芳叔胺HMA中,与氮原子相连的亚甲基的氢被摘去形成相应的碳自由基,它能引发单体聚合成为聚合物的端基。这也由聚合物的UV光谱所证实,由实验结果提出这类体系的引发机理。