某取排水车180°铰接式弯管优化分析

为了解决新型铰接式弯管的变形问题,利用ANSYS软件对铰接式弯管进行建模和流固耦合分析,发现原始弯管两侧中部内凹、弯径增大、最大应力超过许用应力,据此提出了导流器错位排布方案.结果 表明:采用方案三错位排布导流器方案、将导流器间距设为70 mm时得到最优方案,优化后的弯管4最大应力由178.12 MPa降低到92.4 MPa、降低了52％,弯管12最大应力由289.52 MPa降低到135.4 MPa、降低了47％,取得了较好的优化效果,为180°弯管导流器设计提供了一种新方案.     

Enzyme-Activated Prodrug-Based Smart Liposomes Specifically Enhance Tumor Hemoperfusion with Efficient Drug Delivery to Pancreatic Cancer Cells and Stellate Cells

Tumor-specific enhanced delivery of chemotherapeutics and modulators to tumor cells and activated pancreatic stellate cells (aPSCs), respectively, represents safer and more effective therapy for pancreatic cancer. Herein, a membrane type 1-matrix metalloproteinase (MT1-MMP)-cleavable spacer is used to assemble low-density cRGDfK onto thermosensitive liposomes loaded with phosphorylated calcipotriol (PCAL) and doxorubicin (DOX), yielding MR-T-PD. The liposome-linked cRGDfK prodrug on MR-T-PD surface is first activated by MT1-MMP, which is selectively expressed on tumor endothelial cells, to release cRGDfK. The free cRGDfK specifically promotes tumor angiogenesis, leading to 3.4-fold higher accumulation and a wider distribution of MR-T-PD in tumors. Furthermore, MR-T-PD rapidly releases PCAL and DOX into the interstitium under heat treatment. The released DOX enters tumor cells to induce apoptosis, whereas the PCAL prodrug is converted to CAL by alkaline phosphatase on the surface of aPSCs; CAL can then enter aPSCs to induce quiescence and promote the antitumor effect of DOX. Finally, by enhancing the exposure of DOX and CAL to tumor cells and aPSCs, respectively, in a tumor-specific manner, MR-T-PD exerts superior efficacy (a 5.9-fold decrease in tumor weight) without causing additional side effects. Overall, this prodrug-based smart liposome system represents a promising paradigm for pancreatic cancer therapy.     

Characteristic tryptic peptides and gelling properties of porcine skin gelatin affected by thermal action

Thermal action in extraction process had effects on characteristic tryptic peptides identification and gelling properties of porcine gelatin. SDS-PAGE, HPLC-LTQ/Orbitrap high-resolution mass spectrometry, texture analyser and rheometer were used to evaluate collagen depolymerisation degree, characteristic tryptic peptides and gelling properties of gelatins prepared in various thermal actions. Results showed that with increasing temperature and time, depolymerisation degree enlarged, while gel strength, gelling and melting temperature decreased. Mass spectra showed that 47 and 49 common characteristic tryptic peptides were identified in gelatins extracted at 50 °C and 100 °C with various times, respectively. Moreover, 34 common characteristic tryptic peptides were identified in all gelatin samples. Further comparison between this work and our previous investigations yielded 20 common characteristic tryptic peptides, which stably exist in various thermal actions. These common characteristic tryptic peptides may be very helpful for the accurate authentication of porcine gelatin.     

Anthocyanin-fortified konjac glucomannan/sodium alginate composite edible boba: characteristics of texture,microstructure, in vitro release behaviour and antioxidant capacity

Konjac glucomannan/sodium alginate composite edible boba (KGM/SA-boba) with good taste is very popular in China, and it is an outstanding carrier for health potential ingredients. In this work, KGM/SA-boba were fortified with 0.25, 0.50, 0.75 and 1.00% purple sweet potato anthocyanin (PSPA), then characterised by the water distribution, texture, microstructure, in vitro release property of PSPA and antioxidant capacity. LF-NMR analysis demonstrated that the free water of KGM/SA-boba could transfer to tightly bound water with the addition of PSPA that made it with better water-binding ability, higher springiness and lower hardness. And the results of SEM and rheology showed that PSPA could stabilise the microstructure of KGM/SA-boba by forming more amorphous regions and hydrogen bonds proved by the results of DSC and FT-IR. Furthermore, 50% of PSPA in PSPA-fortified KGM/SA-boba can be released at the first hour in a simulated gastrointestinal environment. And the scavenging capacity of DPPH and ABTS of the PSPA-fortified KGM/SA-boba after digestion was higher than that of PSPA alone. Generally, PSPA could improve the texture while KGM/SA-boba in turn would make PSPA more stable in the gastrointestinal digestive system.     

Acid–base transport model depicting the dynamic pH response of interfacial reactions

Acid–base transport is integral to many important interfacial reactions in various fields of chemistry, but its theoretical foundation is lacked. Herein, a common acid–base transport model is established owing to the success in deriving buffer transport equations. This model is applicable to most buffer systems by flexibly integrating the transport equations in terms of buffer components, and is verified through the model relationships of buffer transport limiting current by using hydrogen evolution reaction experiments. Based on model calculations, two diagram approaches are proposed to depict the dynamic pH response and aid buffer operation optimizations. The model and methods allow us to quantify the rate-limiting effect of acid–base transport on interfacial reactions and to precisely control the effect through medium regulations. Furthermore, the model has laid the foundation of dynamic pH effect on species transformation and process mechanism, which can be of wide interest in the chemistry encompassing interfacial reactions.     

Elliptical distribution-based weight-determining method for ordered weighted averaging operators

The ordered weighted averaging (OWA) operators play a crucial role in aggregating multiple criteria evaluations into an overall assessment supporting the decision makers’ choice. One key point steps is to determine the associated weights. In this paper, we first briefly review some main methods for determining the weights by using distribution functions. Then we propose a new approach for determining OWA weights by using the regular increasing monotone quantifier. Motivated by the idea of normal distribution-based method to determine the OWA weights, we develop a method based on elliptical distributions for determining the OWA weights, and some of its desirable properties have been investigated.     

露天采场高陡边坡下深部采空区的爆破处理研究

鞍本地区是我国最大的BIF型铁矿集中分布区,其铁矿资源量/储量约占全国总量的1/4,但由于日伪时期的掠夺式开采和矿业整合开发前的无序开发利用,在一定深度空间内遗留了大量隐伏采空区,为后期实现规模化露天开采带来极大的安全隐患,成为制约露天铁矿资源安全高效开采的难题。以弓长岭露天铁矿大砬子采区高陡边坡下的深部采空区为研究对象,利用LS_DYNA软件进行采空区的安全爆破模拟研究,结合现场深部采空区爆破参数试验结果,提出了采用孔中起爆处理采空区的方法,具体参数设置为空区预留顶板厚度3 m,孔间延期时间42 ms,排间延期时间75 ms,平均炸药单耗0.237 kg/t。在上述分析的基础上,针对大砬子露天采场高陡边坡内的深部不规则多层采空区提出了分层、分区安全爆破处理的技术方案,且空区边界用切割爆破方法处理,爆破处理效果良好,采空区得到了安全有效治理。     

A first-principles investigation on mechanical and metallic properties of titanium carbides under pressure

The titanium carbides are potential candidates to achieve both high hardness and refractory property. We carried out a structural search for titanium carbides at three pressures of 0 GPa, 30 GPa and 50 GPa. A phase diagram of the Ti-C system at 0 K was obtained by elucidating formation enthalpies as a function of compositions, and their mechanical and metallic properties of titanium carbides were investigated systematically. We also discussed the relation of titanium concentration to the both mechanical and metallic properties of titanium carbides. It has been found that the average valence electron density and tractility improved at higher concentrations of titanium, while the degree of covalent bonding directionality decreased. To this effect, the hardness of titanium carbide decreases as the content of titanium increases. Our results indicated that the titanium content significantly affected the metallic properties of the Ti-C system.     

小麦肽协同有机酸对花生红衣原花青素抗氧化稳定性的影响

将花生红衣原花青素与小麦肽复配(质量比30∶1),分别采用不同有机酸(柠檬酸、苹果酸、醋酸、乳酸)调节溶液pH为5.0,经不同热处理后,以ABTS自由基、DPPH自由基以及超氧阴离子自由基清除率为指标,研究小麦肽协同有机酸对原花青素抗氧化稳定性的影响。结果表明:在清除ABTS自由基方面,经90℃加热后小麦肽与苹果酸的协同具有良好的稳定效果,经121℃加热后小麦肽与苹果酸、醋酸的协同都具有良好的稳定效果;在清除DPPH自由基方面,经90℃加热后小麦肽与柠檬酸的协同具有良好的稳定效果;在清除超氧阴离子自由基方面,小麦肽与柠檬酸协同在未加热与121℃加热后时具有良好稳定效果,小麦肽与醋酸协同在未加热与90℃加热后具有良好的协同效果。可见,小麦肽协同有机酸可以在一定程度上稳定花生红衣原花青素的抗氧化性,稳定效果因有机酸、样品体系的热处理及清除自由基种类的不同而有所不同。     

高粘度流体横掠麻面管的传热与流动特性研究

采用三维数值模拟方法,研究不同Re(381、572、763、954、1144)下凹坑直径d(1.8、2.0和2.2 mm)、深度h(0.9、1.0和1.1 mm)、轴向距离p(10、12和14 mm)、周向距离l(5.236、6.283和7.854 mm)与布置型式(叉排、顺排)对高粘度润滑油横掠麻面管流动与传热的影响。结果表明:外壁周期性凹坑的存在使得麻面管油侧换热增强,同时减阻效果明显;相比于光管,当Re=381～1 144时,麻面管油侧Nu增加了28.6%～55.4%,阻力系数f减小了0.59%～26.9%,综合换热性能指标η为1.05～1.59。