兆瓦级风力发电机主要承载螺栓强度的有限元计算

兆瓦级风力发电机承受载荷复杂,受风速变化及本身支撑结构的影响较大,载荷有一定的随机性,因此在设计中必须考虑多自由度上多个载荷的叠加作用,传统工程算法一般只能考虑螺栓连接处的单轴受载情况已经不再适应。为了尽量模拟实际受载情况,采用了ANSYS对兆瓦级风力发电机轮毂与主轴的连接螺栓做有限元分析,载荷基于动力学计算软件计算得出的时间序列,对连接螺栓本身,在极限载荷与疲劳载荷下进行了仿真计算。     

四川盆地中二叠统热液白云岩化作用及其储层改造意义

四川盆地中二叠统热液白云岩类型多、分布广,对油气勘探具有重要意义,但是关于热液白云岩化作用的机理和模式及其对储层的改造意义存在较多争议。在系统收集前期研究资料的基础上,通过对典型地区热液白云岩的矿物学、岩相学和地球化学等详细分析,总结了热液白云岩化作用的机理及其储层改造意义。研究认为:四川盆地中二叠统热液白云岩化作用与围岩的岩性和岩相没有明显的相关性,主要与同期断裂活动有关。根据热液白云岩与围岩的关系,可以将热液白云岩化模式分为3类:(1)滩相改造型热液白云岩化,主要分布在川西和川中地区的栖霞组中,热液白云岩化作用对储层的建设性改造作用不明显;(2)岩溶灰岩改造型热液白云岩化,主要分布在川中地区的茅口组中,热液白云岩化作用对该类储层的建设性改造作用也不明显;(3)致密灰岩改造型热液白云岩化,主要发育在川东地区的茅口组中,热液白云岩化作用对该类储层的建设性改造作用比较明显。断裂裂缝、充填残余的溶蚀孔和白云石晶间孔是热液改造型储层的主要储集空间,相比于原岩物性较好的储层,原始储集物性较差的储层受热液及其相关构造作用改造后,物性改善更加明显。     

Annealing-Free Thioantimonate Argyrodites with High Li-Ion Conductivity and Low Elastic Modulus

Although Li-ion superconducting sulfides have been developed as solid electrolytes (SEs) in all-solid-state batteries, their high deformability, which is inherently beneficial for room-temperature compaction, is overlooked and sacrificed. To solve this dilemmatic task, herein, highly deformable Li-ion superconductors are reported using an annealing-free process. The target thioantimonate, Li_5.2Si_0.2Sb_0.8S₄Br_0.25I_1.75, comprising bimetallic tetrahedra and bi-halogen anions is synthesized by two-step milling tuned for in situ crystallization, and exhibits excellent Li-ion conductivity (σ_ion) of 13.23 mS cm⁻¹ (averaged) and a low elastic modulus (E) of 12.51 GPa (averaged). It has a cubic argyrodite phase of ≈57.39% crystallinity with a halogen occupancy of ≈90.67% at the 4c Wyckoff site. These increased halogen occupancy drives the Li-ion redistribution and the formation of more Li vacancies, thus facilitating Li-ion transport through inter-cage pathway. Also, the facile annealing-free process provides a unique glass-ceramic structure advantageous for high deformability. These results represent a record-breaking milestone from the combined viewpoint of σ_ion and E among promising SEs. Electrochemical characterization, including galvanostatic cycling tests for 400 h, reveals that this material displays reasonable electrochemical stability and cell performance (150.82 mAh g⁻¹ at 0.1C). These achievements shed light on the synthesis of practical SEs suffice both σ_ion and E requirements.     

中国南方海相层系油气成藏特点与勘探方向

在漫长的地质历史中,中国南方地层经历了多旋回构造运动与强烈后期改造,中、古生界油气的生成、运移、聚集成藏、保存和破坏经历了多期阶段式发展和演化的复杂过程。以四川盆地为代表的构造相对稳定、保存条件好的地区,具有多源供烃、早期聚集、油气转化、晚期定型的特点;中、下扬子中、新生界覆盖区,具有二次生烃、晚期成藏的特点;湘鄂西、滇黔桂等碳酸盐岩裸露区,则表现为早期生烃、后期破坏改造的特点。依据生烃期的早晚以及油气在完成初次聚集后至最终成藏定型是否突破了原始封闭体系,南方海相油气成藏模式可划分为原生型、次生型和再生型3种类型。依据不同地区的成藏条件与特点,南方海相领域的油气勘探应按重点展开、力求突破和区域侦察3个层次进行,即重点展开四川盆地区,力求突破黔西北地区、中扬子江汉平原南部及下扬子句容、海安地区,区域侦察黔南、滇桂及湘鄂西地区。     

数字网络型光纤振动传感系统

设计了一种新型光纤振动传感系统,该系统借鉴光通信中的无源光网络(PON)技术、光纤时分和波分混合复用传感侦测技术组建了数字网络型无源传感网络,系统传感单元的最大容量为32×8,有效地扩大了传感范围,实现了多传感单元系统化的集中管理,在处理算法中采用动态阈值自适应管理,可以根据环境变化实时改变阈值.在报警处理中,采用声、...     

Hybrid fractal image coding with quadtree-based progressive structure

A progressive structure which takes the quadtree depth into consideration is proposed for fractal image coding. Simulation results show that its image quality at different received data rates is better than that without considering the quadtree level. Then, a hybrid fractal image coding scheme based on traditional and no-search fractal image coding with the proposed progressive structure is suggested. The image quality and compression ratio can be controlled by a threshold, which makes it downward compatible to the no-search fractal image coding. Experimental results justify that the progressive performance of the proposed scheme is better than that of traditional fractal image coding.     

MPEG-A: multimedia application formats

MPEG standards, instrumental in shaping the multimedia landscape since the early 1990's, are taking another step forward with MPEG-A, which specifies multimedia application formats. MAFs are essentially superformats that combine selected technology components from MPEG (and other) standards to provide greater application interoperability, which helps satisfy users' growing need for better-integrated multimedia solutions.     

Effects of dopamine reuptake inhibitors on food- and cocaine-maintained responding: II. Comparisons with other drugs and repeated administrations.

A previous study (J. R. Glowa, F. H. E. Wojnicki, D. Matecka, et al, 1995) showed that acute doses of GBR 12909 selectively decreased cocaine-maintained responding without affecting food-maintained responding. This report extended these observations to some related drugs and to the effects of repeated administration. When responding was maintained under a multiple fixed ratio (FR) 30 food, FR 30 cocaine schedule, acute doses of GBRR 12935, CFT, and d-amphetamine decrease cocaine-maintained responding more than food-maintained responding. However, in contrast to GBR 12909, none of these drugs completely decreased cocaine-maintained responding without affecting food-maintained-responding. Repeated administration of GBR 12909 sustained and of GBR 12935 improved, these selective deceases in cocaine-maintained responding. The selective effect of these dopamine reuptake inhibitors on cocaine-maintained responding is consistent with their known pharmacological selectivity for the dopamine reuptake side and can be well-maintained with repeated administration. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hyper-crosslinked sorbents for hemoperfusion

Pore structure changes of swelling sorbents, which were obtained from styrene and divinylbenzene (DVB) by additional crosslinking with α,α′-dichloro-p-xylene in the presence of tin chloride catalyst and in dichloroethane solution, were examined. It was found that the amount of dichloroxylene influences the swelling decrease and the increase of sorption ability of sorbents for chemical compounds with low molecular weight. Hemocompatibility was imparted to the sorbent and it was useful for hemoperfusion when a small amount of sulfonyl groups (about 0.2 mmol/g) had been introduced.     

Dialdehyde Starch Nanocrystals as a Novel Cross-Linker for Biomaterials Able to Interact with Human Serum Proteins

In recent years, new cross-linkers from renewable resources have been sought to replace toxic synthetic compounds of this type. One of the most popular synthetic cross-linking agents used for biomedical applications is glutaraldehyde. However, the unreacted cross-linker can be released from the materials and cause cytotoxic effects. In the present work, dialdehyde starch nanocrystals (NDASs) were obtained from this polysaccharide nanocrystal form as an alternative to commonly used cross-linking agents. Then, 5–15% NDASs were used for chemical cross-linking of native chitosan (CS), gelatin (Gel), and a mixture of these two biopolymers (CS-Gel) via Schiff base reaction. The obtained materials, forming thin films, were characterized by ATR-FTIR, SEM, and XRD analysis. Thermal and mechanical properties were determined by TGA analysis and tensile testing. Moreover, all cross-linked biopolymers were also characterized by hydrophilic character, swelling ability, and protein absorption. The toxicity of obtained materials was tested using the Microtox test. Dialdehyde starch nanocrystals appear as a beneficial plant-derived cross-linking agent that allows obtaining cross-linked biopolymer materials with properties desirable for biomedical applications.