Photo‐Induced Functionalization of Spherical and Planar Surfaces via Caged Thioaldehyde End‐Functional Polymers

The synthesis and application of a novel reversible addition‐fragmentation chain transfer (RAFT) agent carrying a photocaged thioaldehyde moiety is described (λ_max = 355 nm). RAFT polymerization of styrene, dimethylacrylamide and a glycomonomer is evidenced (3600 g mol^?1 ≤ M_n ≤ 15 000 g mol^?1; 1.07 ≤ ? ≤ 1.20) with excellent end‐group fidelity. The photogenerated thioaldehyde on the chain ends can undergo hetero Diels–Alder reactions with dienes as well as reactions with nucleophiles. The terminal photoreactive polymers are photografted to porous diene‐reactive polymeric microspheres. The grafted particles are in‐depth characterized via scanning electron microscopy, elemental analysis, X‐ray photoelectron spectroscopy, and high resolution FT‐IR microscopy, leading to a qualitative as well as quantitative image of the core–shell objects. Grafting densities up to 0.10 molecules nm^?2 are reached. The versatility of the thioaldehyde ligation is evidenced by spatially resolved grafting of polystyrene onto nucleophilic groups present in poly (dopamine) (PDA)‐coated glass slides and silicon wafers via two‐photon direct laser writing (DLW) imaged by ToF‐SIMS. The combination of thioaldehyde ligation, RAFT polymerization, and DLW allows for the spatially resolved grafting of a vast range of polymers onto various substrates in any desired pattern with sub‐micrometer resolution.     

一种基于飞秒激光白内障手术的碎核轨迹设计

针对在飞秒激光辅助晶状体碎核中,需要根据白内障患者的晶状体浑浊等级选择不同的扫描方案,且其每一层的扫描轨迹不连续的问题,提出了一种参数化的螺旋形激光扫描碎核轨迹。对螺旋形扫描轨迹进行了整体参数化定义,解出了扫描轨迹的数学模型,并求解了轨迹中关键数据点的坐标值。最后对扫描轨迹数学模型建立了仿真,其仿真结果验证了所求解扫描轨迹数学模型的正确性。此种碎核方案的每一层轨迹连续,可通过改变相应参数实现不同的切割效果,为飞秒激光辅助白内障手术提供了一种新型的碎核方案,具有一定的实用价值。     

35 mm高炮弹药发展设想与分析

高炮武器系统的发展不仅要重视自动炮技术的改进和发展,同时还要重视弹药系统的技术发展。35mm弹药的今后发展方向主要是发展智能化和可控化的高新技术弹药。为对付不同类型的空中目标,主要发展的新弹种有改进型AHEAD弹、35mm集束穿甲弹和35mm弹道修正弹。AHEAD弹的优点是:与直接命中的炮弹相比具有更高的命中概率,可拦截特别小的目标。AHEAD弹比一般近炸引信炮弹的抗干扰能力强,效费比好。AHEAD弹的电子时间引信不受敌方电磁干扰。对几种弹药的毁歼概率进行了分析计算。     

An efficient fluid-solid coupled finite element scheme for weapon fragmentation simulations

An efficient finite element (FE) scheme to deal with a class of coupled fluid-solid problems is presented. The main ingredients of such methodology are: an accurate Q1/P0 solid element (trilinear in velocities and constant piecewise-discontinuous pressures); a large deformation plasticity model; an algorithm to deal with material failure, cracking propagation and fragment formation; and a fragment rigidization methodology to avoid the possible numerical instabilities that may produce pieces of material flying away from the main solid body. All the mentioned schemes have been fully parallelized and coupled using a loose-embedded procedure with a well-established and validated computational fluid dynamics (CFD) code (FEFLO). A CSD and a CFD/CSD coupled case are presented and analyzed.     

基于蒙特卡洛法的战斗部破片毁伤仿真

建立了战斗部破片对目标关键部件的毁伤计算的蒙特卡洛仿真模型, 将破片的毁伤能力指标加以量化. 以防空导弹打击空中目标为例, 验证了方法的有效性, 可为导弹武器打击目标的毁伤效果计算提供决策依据.     

Evaluating the profile of myofibrillar proteins and its relationship with tenderness among five styles of dry-cured hams

In order to investigate the relationship between profile of myofibrillar proteins and tenderness among 2 kinds of Chinese hams (Jinhua and Xuanwei) and 3 kinds of European hams (Iberian, Serrano and Parma), shear force, myofibril fragmentation index (MFI), SDS-PAGE, carbonyls content and Raman spectroscopy were investigated. The shear force and salt content of Chinese hams were significantly higher than that of European hams, while moisture content was lower than that of European hams (p < 0.05). MFI values and SDS-PAGE profile revealed that the degradation of myofibrillar proteins in Chinese hams was lower than in European hams. In addition, Chinese hams showed significantly higher carbonyls content and β-sheet content compared with European hams, indicated that proteins aggregation intensively inhibited the degradation of myofibrillar proteins in Chinese hams. These results indicated that the higher shear force in Chinese style hams could be attributed to the lower moisture content and limited proteolysis.     

不同前处理方式对沙枣叶总黄酮提取的影响

取沙枣叶采用超声波法提取总黄酮,紫外-可见分光光度法测定含量。分别对干燥方法,烘干温度,破碎度对其总黄酮得率的影响进行研究,同时考察了不同生长期沙枣叶中总黄酮含量变化。结果表明,冻干法处理后提取沙枣叶总黄酮得率最高,达到1.62%;其次为烘干法,最佳烘干温度为80℃,最佳破碎度为60目,此条件下总黄酮得率为1.57%;5月~9月生长期间,9月摘取沙枣叶最为适宜,测定总黄酮含量为1.78%。     

Woody Breast短期贮藏中肉质的变化

为研究近年来速生型肉鸡鸡胸肉硬度缺陷(woody/wooden breast,WB)俗称木质肉在短期贮藏中生肉肉质参数的变化。实验选取68只42日龄Cobb 500肉鸡作为研究对象,经宰杀后人工分级为低(normal,NORM)、高(severe,SEV)两组(n=34只/组)。在不同时间节点下(1、3、8 d)对所有样本测定质量、挤压力(compression force,CF)、滴水损失(drip loss,DL)、肌节长度(sarcomere length,SL)及肉破碎化指数(gravimetric fragmentation index,GFI)。对所有参数进行组间(不同WB等级间,不同时间节点)显著性分析,同时对各参数与WB等级间进行相关性分析。结果表明:SEV样本质量、CF、SL、GFI在贮藏时间节点处都显著高于NORM样本(P0.05),DL在1 d时NORM与SEV间无差异,在3~8 d时显著上升(P0.05)。CF、SL、GFI在1~3 d时,所有样本都显著减小(P0.05),3~8 d时CF无显著变化(P0.05),SL、GFI在NORM样本间无差异但在SEV样本间继续减小(P0.05)。相关性分析表明,CF、累积DL与WB等级极显著相关(P0.01),SL、GFI随时间变化与WB硬度减小存在联系。综上可知,SEV生肉肉质较NORM差,WB硬度随贮藏时间变长而减小,但其生肉品质并不会发生改变,因此对WB检测应在宰杀当天在线进行,且WB硬度由多种原因共同作用导致。     

Effect of modified atmosphere packaging on structural and physical changes in buffalo meat

The effect of modified atmosphere packaging of buffalo meat on the structural parameters viz., fibre diameter, sarcomere length and myofibrillar fragmentation index and physical parameters viz., pH, drip loss and colour scores were studied. The buffalo meat was packed under aerobic, vacuum and modified atmosphere (80% oxygen+20% carbon dioxide) and stored at 4±1°C upto 21 days. The results obtained revealed that vacuum-packed buffalo meat had the lowest fibre diameter and myofibrillar fragmentation index and the highest sarcomere length, vacuum thus appears to enhance ageing. Buffalo meat packed in modified atmosphere had a low drip loss and a desirable colour. The modified atmosphere packed and vacuum-packed buffalo meat was acceptable for upto 14 days at 4±1°C.