Testing study of subcritical crack growth rate and fracture toughness in different rocks

Subcritical crack growth of double torsion specimens made of ore, lherzolite, marble and granite was studied using Instron1342 type electro hydraulic servo test machine. The relations of the mode-I stress intensity factor KI versus the subcritical crack growth velocity v and the fracture toughness KIC were obtained by the double torsion constant displacement load relaxation method. The behavior of subcritical crack growth was analyzed for different rocks. The results show that lgKI—lgv relations of four kinds of rocks measured by this method accord with linear rule, i.e. the relations between subcritical crack growth velocity and stress intensity factor have a power law, which is in good agreement with CHARLES theory. lgKI—lgv curves move to top left corner with the decrease of the elastic modulus, which implies that the subcritical crack growth velocity speeds up. The maximum subcritical crack growth velocity exhibits negative exponential increase, and mode-I fracture toughness KIC decreases with the decrease of elastic modulus. The testing results provide a basis for time-dependence of rock engineering stability.

Growth, Optical, Mechanical and Dielectric Properties of Glycine Zinc Chloride NLO Single Crystals

Single crystals of Glycine Zinc Chloride (GZC) were grown from aqueous solution by slow evaporation technique. Single crystal X-ray diffraction analysis reveals that the crystal belongs to orthorhombic system with the space group Pna21.The optical transmission study reveals the transparency of the crystal in the entire visible region and the cut off wavelength has been found to be 230 nm. The optical band gap is found to be 3.40eV. The transmittance of GZC crystal has been used to calculate the refractive index (n), the extinction coefficient (K) and the real er and imaginary ei components of the dielectric constant. Mechanical studies were carried out on the as grown crystal. Dielectric constant and dielectric loss measurements were carried out at different temperatures and frequencies. Photoconductivity measurements carried out on the grown crystal reveal the negative photoconducting nature.

Growth, Thermal, Mechanical and Dielectric Studies of Glycine Doped Potassium Acid Phthalate Single Crystals

Single crystals of glycine doped potassium acid phthalate (KAP) have been grown from low temperature solution growth method by employing slow evaporation of the solvent at room temperature. The grown crystal was subjected to various studies such as X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), UV-visible and Second Harmonic Generation (SHG) studies. The thermal stability, mechanical strength and dielectric constant were also measured. The various studies revealed the influence of the glycine on KAP and the investigations indicated that glycine played an important role in the changes of the spectral, optical and mechanical properties of KAP crystals.

恒静载降K法测定焊缝疲劳裂纹扩展门槛值研究

焊接残余拉应力会显著降低焊接接头疲劳性能,因此,焊接结构疲劳寿命评估参数的测定应对焊接残余应力予以充分考虑.为测得考虑焊接残余应力影响条件下的疲劳裂纹扩展门槛值,本文提出通过设定恒定平均外载以等效残余应力作用,进而逐级降低裂尖应力强度因子范围(ΔK)测得焊缝疲劳裂纹扩展门槛值的方法,即恒静载降K法.通过与ASTM E647-15等标准推荐测试方法所得结果对比,探究了恒静载降K法测量值适用性;通过扫描电镜(SEM)、电子背散射衍射(EBSD)等手段观察,对比分析了不同测量方法近门槛值载荷下的裂尖材料疲劳断口和变形行为.结果表明:采用恒静载降K法测量焊缝疲劳裂纹扩展门槛值最低,采用恒最大应力强度因子(K_(max))降载法的测量值次之,采用恒应力比(R)降载法的测量值最高.对比不同裂纹尖端K_(max)设定对门槛值测量的影响,发现随着K_(max)增大,门槛值测量值先快速下降,随后趋于平稳;采用恒静载降K法测定过程中K_(max)呈逐渐上升趋势,相应的门槛值测量值最低.疲劳断口显示,随着外加平均载荷增大,在近门槛值阶段断口形貌由疲劳辉纹转变为微区解理断裂;基于EBSD表征计算的裂尖材料几何必需位错密度表明,随着近门槛值外载的平均载荷增大,裂纹尖端位错密度增加.

Effect of NaCl Doping on Growth, Characterization, Optical and Dielectric Properties of Potassium Hydrogen Phthalate (KHP) Crystals

Single crystals of sodium chloride doped Potassium Hydrogen Phthalate (KHP) were grown from aqueous solution by slow evaporation method at room temperature. The powder X-ray diffraction analysis was carried out and lattice cell parameters estimated. FTIR studies confirm the presence of functional groups and slight distortion of groups due to doping of sodium metal. UV-visible and photoluminescence spectral studies revealed to understand the optical properties. The NLO property of grown crystals has been confirmed by Kurtz powder technique. Dielectric studies of samples showed that dielectric constant decreased slowly with increasing frequency and attains saturation at higher frequencies.

Synthesis, Growth and Material Characterization of Bis L-Alanine Triethanol Amine (BLATEA) Single Crystals Grown by Slow Evaporation Technique

Bis L-alanine Triethanol amine (BLATEA) salt was synthesized by solution method and it was subjected to solubility studies. Using the solubility data, the saturated solution of the synthesized salt was prepared and single crystals of Bis L-alanine Triethanol amine (BLATEA) were grown from aqueous solution by slow evaporation technique. X-ray diffraction (XRD) study was carried out to confirm the crystal structure. FTIR study reveals the functional groups of the sample. UV-Visible transmittance and absorption spectra were recorded for the sample to analyze the transparency of the grown crystal. Vickers micro hardness values were measured for the sample and from the microhardness study it is observed that BLATEA crystal is a soft material. SHG generation study was carried out to confirm the NLO activity of grown sample and also BLATEA crystal has been analyzed with dielectric

高磁感取向硅钢Goss织构形成机制的研究进展

基于Goss织构异常长大可获得良好磁性能和工业生产高磁感取向硅钢产品工艺流程的背景,系统分析了Goss织构异常长大理论研究进展,着重剖析了Goss织构异常长大选择生成、定向遗传、择优长大的机制,阐述了抑制力近恒量取向硅钢生产技术的特征,为取向硅钢生产工艺技术提供理论支撑。

我国纺织服装产品出口RCEP成员国增长因素分析

为了分解出我国纺织服装出口增长的驱动因素,文章基于恒定市场份额(CMS)模型对2009—2021年《区域全面经济伙伴关系协定》(RCEP)框架下中国纺织服装产品出口的数据进行实证分析。研究显示:中国纺织服装产品出口总体呈现升—降—升的趋势,进口规模效应对出口增长的主导作用随着时间在减弱,而出口竞争力效应有所增强;此外,中国纺织服装产品出口东盟十国的增长远大于澳大利亚、日本、韩国和新西兰,而东盟十国中又以越南出口增长份额最高;中国纺织服装产品出口正在从需求导向驱动型向竞争力驱动型转型,但转型速度较慢。通过运用CMS模型,为分析中国纺织服装产品出口增长动力提供了新的视角和依据,有助于深入理解在全球经济一体化背景下,特别是RCEP框架内,中国纺织服装产品出口增长的具体驱动机制,促进产业转型升级和可持续发展。

桂北山区稻田罗非鱼生长性能研究

在桂北高寒山区开展稻田罗非鱼生态养殖试验。通过分析罗非鱼生长常数、特定生长率、血液生理生化指标,探究罗非鱼在高寒山区稻田的生长性能。结果表明,在水温26.4℃时,生长常数最大值为0.76 d,罗非鱼在桂北山区稻田获得良好的生长性能。对罗非鱼特定增长率和日增质量与水温的关系二次回归曲线进行拟合,水温与罗非鱼特定生长率相关曲线为y=0.1129x2-6.6352x+98.537(R2=0.6345),水温与饵料系数相关曲线为y=-0.0013x2+0.0922x-0.2948(R2=0.4418),罗非鱼在桂北地区稻田最佳生长水温为26.4℃。在水温22.0~29.0℃时,血液生理生化指标表明,高寒山区罗非鱼能保证机体组织器官的完整性和正常功能。

含镓石榴石系列大晶格常数磁光衬底单晶研究进展

近年来,光通信技术与集成电子器件飞速发展,以稀土铁石榴石(RIG)为代表的磁光薄膜被视为应用于近红外通信窗口最具潜力的磁光材料。为了尽量减小磁光薄膜在制备过程中相关性能受到的影响,衬底材料的选择成为关键。制备RIG磁光薄膜通常采用Si类及石榴石氧化物类作为衬底材料。RIG磁光薄膜的晶格常数一般在12.4左右,含镓类石榴石氧化物单晶衬底基片与其晶格常数相近,具有大晶格常数特性,是其合适的衬底材料之一。但是,由于原料氧化镓高温易挥发,使含镓类石榴石单晶制备成为一直以来关注和讨论的热点。深入研究含镓类石榴石衬底单晶有望促进新一代磁光器件的发展。本文综述了在含镓类石榴石系列单晶中,氧化物磁光衬底单晶的研究进展,总结了本团队在该类晶体生长、晶体结构、关键参数等方面的研究工作,展望了该类晶体的研究发展趋势。

关于梯度Yamabe孤立子的平凡性结果

研究完备非紧梯度Yamabe孤立子,在势函数梯度模长在无穷远处极限为0,或孤立子具有多项式体积增长,或孤立子随机完备的假设下,得到该类梯度Yamabe孤立子的平凡性结果,进而证得其数量曲率为常数。

RE(C_7H_5O_3)_2(C_9H_6NO)配合物抗真菌作用的热动力学研究

应用微量热法研究了配合物RE(C7H5O3)2(C9H6NO)(RE代表La,Sm和Nd)对真菌的抗菌作用。在TAM Air热导式等温微量量热仪上,分别测定了桔青霉菌和黑曲霉菌在不同浓度不同稀土配合物及空白条件下生长代谢热谱曲线,并计算得到了真菌在不同条件下的生长代谢速率常数κ和传代时间G等热动力学参数。实验表明:3种稀土水杨酸8-羟基喹啉三元配合物对桔青霉菌和黑曲霉菌均有抑制作用,其抑制效果依次为:Sm(Hsal)2(hq)>La(Hsal)2(hq)>Nd(Hsal)2(hq)。

微量量热法测定细菌的最佳生长温度

In this paper, thermograms of eight bacteria and growth ctirves in exponential phase of growth are presented. Growth rate constants and their temperature dependent non-llnear equations axe also established. The optimu-m growth temperattire of these bacteria can be easily caJculated from such equations. It is very informative for the study of microorganism growth.

生长阶段及温度对微藻细胞总ATP酶活性的影响

以亚心形扁藻（Platymonas subcordiformis）、大溪地球等鞭金藻（Isochrysis galbana daxidi）和小新月菱形藻（Nitzschia closterium）为实验对象,探讨批次培养过程中不同生长阶段及不同温度处理的藻细胞总ATP酶活性。结果表明：三种微藻在不同生长阶段的细胞总ATP酶活性均有显著变化。同一种微藻生长繁殖越快的阶段,其相对生长常数K和藻细胞总ATP酶活性也越大。不同生长阶段亚心形扁藻、大溪地球等鞭金藻和小新月菱形藻的相对生长常数K与其细胞总ATP酶活力均具有显著的正相关（P〈0.05）,其相关系数r分别为0.92、0.79、0.82。亚心形扁藻在25~27℃之间细胞总ATP酶活性无显著变化,在30℃以上细胞总ATP酶活性显著下降。大溪地球等鞭金藻在25~30℃,细胞总ATP酶活性随温度的升高而显著升高,温度高于30℃细胞总ATP酶活性则急剧下降。小新月菱形藻在经20℃以上温度处理后,细胞总ATP酶活性总体上随温度的升高而显著降低。本研究表明藻细胞的总ATP酶活性与微藻细胞生长活力密切相关,并可应用于微藻适宜培养温度的筛选。

温度、pH、药物对大肠杆菌抑制作用的量热法研究

本实验用热活性检测系统测定了大肠杆菌在不同温度、pH及药物的作用下生长的完整热谱曲线。进而按指数生长模型计算出不同条件下细菌代谢的生长速率常数,并用计算机拟合出生长速率常数与温度、pH及药物浓度之间的关系式,进一步求得大肠杆菌最适生长温度,最低和最高生长温度;最佳生长pH及最低和最高生长pH;甘草液抑菌的最佳浓度。此研究工作的开展对深入研究细菌生长规律及抑制细菌生长提供了一种新的可靠的定量方法。

微量量热法研究天然中药的抗菌作用

目的：利用微量量热法研究细菌在不同条件下的生长规律，评价天然中药的抗菌作用。方法：利用热活性检测仪，测定了白色葡萄球菌、大肠杆菌、福氏１ａ，１ｂ，５ｂ，６，ｘ，ｙ，３及绿脓杆菌在不同条件下的生长热谱曲线。根据细菌生长的Ｍａｌｔｈｕｓ模型，计算出各细菌在指定条件下的生长速率常数。以生长速率常数大小为依据评价天然中药的抗菌性能。结果：定性研究了黄连水煎液对白色葡萄球菌等８种细菌的抗菌作用。定量测定了丹参水煎液对福氏３和绿脓杆菌的抗菌作用，拟合出其抑菌生长的临界剂量分别为２９９．６μｌ／１０ｍｌ和４１．５μｌ／１０ｍｌ。结论：微量量热法是体外研究天然中药抗菌作用的具有理论研究意义和实际应用价值的新方法。

中国园艺产品出口增长的成因分析——基于CMS模型的分解

中国园艺产品持续贸易顺差对于平衡农产品贸易逆差具有重要的作用。对1992—2008年中国园艺产品出口贸易变动情况进行分析,研究结果表明:世界贸易规模的扩大是中国园艺产品出口持续增长的主要原因;商品出口结构对园艺产品出口起阻碍作用,而且阻碍作用越来越明显;市场分布由阻碍作用逐渐转为促进作用,而且促进作用越来越突出;市场竞争力的下降是中国园艺产品出口放缓的主要原因,而且阻碍作用进一步加大。

微量量热法研究异喹啉类生物碱的抑菌活性

从中草药荷叶、黄连根、黄藤、十大功劳中分别提取出荷叶碱、黄连素、黄藤素、异汉防己碱,并对其进行了表征。用瑞典产八通道微量量热仪(3114/3236 TAM Air)测定了不同浓度的生物碱在不同温度时对大肠杆菌、金黄色葡萄球菌、枯草杆菌代谢作用的热功率-时间曲线,计算出细菌生长的速率常数,建立速率常数与生物碱浓度的方程式、细菌生长速率常数与温度的方程式,进而确定了最佳抑菌浓度和细菌最佳生长温度。

原位生长莫来石增强磷酸铬铝复相陶瓷的制备及性能

以磷酸铬铝粘接剂、熔融石英、氢氧化铝为原料制备莫来石原位增强磷酸铬铝复相陶瓷，采用热分析、XRD、SEM、EDS、矢量网络分析测试等手段，研究不同温度对烧结体物相、显微结构、机械及介电性能的影响，并探讨莫来石原位生长和增强机理。结果表明：在1250～1500℃范围内，随温度升高，材料的致密度、抗弯强度、维氏硬度和介电常数均升高。1500℃煅烧可得致密的原位合成莫来石／磷酸铬铝复相陶瓷，材料晶粒发育比较完善，短棒状莫来石和球状磷酸铬铝晶粒清晰可见，基体致密程度受游离SiO2控制。复合材料介电常数、弯曲强度、维氏硬度分别达到3．7、117MPa和5．3GPa。当煅烧至1600℃时，晶粒快速长大，材料的强度降低。磷酸铬铝与莫来石颗粒间通过弥散强化、细晶强化、晶粒拔出等机制对复合材料起到增强的作用。

超快闪烁晶体碘化亚铜的生长研究

在氮气保护的条件下,采用恒温蒸发法,在乙腈溶液中生长超快闪烁晶体碘化亚铜,获得了尺寸为3 mm×2mm×2 mm的单晶体。测定了CuI在乙腈中的溶解度曲线和结晶度曲线。利用紫外-可见光谱对CuI的乙腈溶液中的碘离子存在形式作了判断和分析,对溶液中的黑色沉淀物氧化铜进行了IR和XRD表征。通过结晶实验,研究了温度、氧气和还原剂对晶体结晶形态的影响。实验表明:晶体生长温度应在45℃以上,铜粉具有很好的还原性能。