某弯管发生刺漏现象,为明确该弯管开裂原因及失效机理,本文采用宏观分析、理化性能、微观分析、腐蚀模拟试验等手段对其进行分析研究.结果表明:该弯管开裂失效机理为硫化氢应力腐蚀,失效的主要原因为,该弯管热煨弯工艺不合理,导致弯曲段产生大量的马氏体组织,马氏体组织硬度较高,对硫化氢应力腐蚀开裂较为敏感;该弯管输送的天然气中含有游离水和硫化氢,硫化氢溶于游离水,对金属基体产生应力腐蚀作用,导致弯管发生开裂.

Combination therapy can be used to enhance the therapeutic response and decrease side effects during cancer treatment. In this study, a system is developed to locally deliver the immune checkpoint blockade antibody targeting programmed death-ligand 1 (anti-PD-L1 or aPD-L1) and doxorubicin (Dox), by an injectable, biocompatible polypeptide hydrogel as a drug depot. The localized and sustained release of Dox after the intratumoral injection of the co-loaded hydrogel induces immunogenic tumor cell death, thus promoting an antitumor immunological response. The tumor inhibitory effect is significantly enhanced by the simultaneous release of aPD-L1 at the tumor site thanks to its action on the inhibition of the PD-1/PD-L1 pathway and restoration of the tumor-killing effect of cytotoxic T cells. Treatment of the B16F10 melanoma model with the aPD-L1 and Dox co-loaded hydrogel leads to a remarkable inhibition of tumor progression and prolongation of animal survival.

为了弄清输油管道绝缘接头失效的原因,通过宏观形貌分析、理化检测、金相显微、扫描电镜等手段对其进行研究分析.绝缘接头用焊接金属环替代了整体式锻造结构,结果表明:右凸缘法兰对裂纹较为敏感;接头短管、左凸缘法兰、接头外层金属维氏硬度存在差别;金相组织为铁素体(Ferrite)+珠光体(Pearlite).该绝缘接头泄漏的主要原因为实际结构不符合SY/T 0516—2016整体型绝缘接头要求,导致右凸缘法兰的剪切强度不够引起撕裂失效.

Physiologically relevant pH- and temperature-responsive polypeptide hydrogels with adhesive properties were developed and characterized.

某高压井口装置平板阀表面发生开裂,通过宏观观察、化学成分分析、拉伸试验、金相检验以及扫描电镜分析等方法,分析了平板阀开裂的原因.结果表明:平板阀敷焊层材料硬度高、韧性差,敷焊层与基体界面处存在分层和气孔,服役过程中阀门承受振动载荷,导致气孔处产生裂纹,以后裂纹扩展直至穿透整个敷焊层而开裂.

对失效接头、保护侧、非阴极保护侧管体进行宏观形貌、组织形貌、腐蚀产物及力学性能进行了研究,结果表明:非保护侧管体内壁腐蚀严重,存在大量腐蚀凹坑;保护侧及非保护侧组织相同,均为铁素体+珠光体.保护侧及非保护侧试样力学性能符合标准,绝缘接头处样品抗拉强度略低于标准上限,不符合设计要求.通过腐蚀产物分析可知,绝缘接头失效主要是由于非保护侧发生二氧化碳局部腐蚀,在管体薄弱焊接处尤为严重,腐蚀由内壁发生、发展,最终形成刺漏,导致绝缘接头失效.

对某井在采油过程中发生的油管挤毁与脱扣事故进行了调查研究.对挤毁油管进行宏观形貌、理化性能、磁粉探伤检测分析,并与同批新油管进行实物挤毁试验模拟.结果表明:该挤毁油管材质及各理化性能均满足生产标准及API 5CT标准要求,其挤毁与失效的原因主要是地层出砂导致油管通道堵塞,造成该井段内外压差超过该油管抗挤强度,从而发生挤毁和脱扣.另外,油管外壁的SCC裂纹及内壁腐蚀对油管被挤毁与脱扣具有不可忽视的作用.

随着油田开发进入高含水期,采出液含水量逐渐增加,导致污水所产生的化学腐蚀性越来越强,对油田生产污水处理单元钢质容器内防腐的要求更苛刻,原来采用的有机内防腐涂层已难以满足要求,这就迫切需要采用新的容器装置内防腐技术.为此,尝试在某油田联合站生产污水处理单元容器沉降罐的内部内衬玻璃钢,并在实际运行的防腐现场进行了1 a多的应用.经检测,沉降罐未出现明显腐蚀渗漏,防腐效果良好,并对比分析了玻璃钢内衬防腐与涂层内防腐的经济性.结果 表明,值得将内衬玻璃钢防腐技术推广应用于油田生产污水处理容器内壁.

5083铝合金具有优良的焊接性能和良好的抗蚀性能,在能源、化工等领域被广泛应用.针对5083铝合金焊接管表面产生裂纹,使用理化检测、扫描电镜、能谱检测、金相显微等技术手段对试样的化学成分、力学性能以及金相组织进行综合分析,发现在试样母材组织和裂纹处存在大量C、Cl、Si、S、O等非金属夹杂.铝合金焊接过程中存在焊接热影响,会导致铝合金焊缝附近存在较大的内应力.结果表明,焊接过程中焊接应力的存在和材料组织中存在大量的非金属夹杂是裂纹产生的根本原因.

In recent years, aggregation-induced emission (AIE) dyes based fluorescent organic nanoparticles (FONs) have achieved significant progress in various biomedical applications. In this work, we developed a covalent strategy to prepare biocompatible AIE-active dyes based cross-linked copolymers (MPC-POSS-PhE) via controllable reversible addition fragmentation chain transfer (RAFT) polymerization using zwitterionic 2-methacryloyloxyethyl phosphorylcholine (MPC), polymerizable AIE dye (named as PhE) and 8-vinyl polyoctahedral silsesquioxanes (POSS) as monomers. Due to the existence of hydrophilic MPC and hydrophobic PhE, the resultant copolymers will self-assemble into core-shell nanoparticles in aqueous solution with ultra-low critical micelle concentration (CMC). This could effectively overcome the drawbacks of non-crosslinked micelles and show more attractive properties and better performance for biomedical applications. Furthermore, the characterization results and biological assays demonstrated that the final MPC-POSS-PhE FONs show stable aqueous stability, uniform size and morphology, high water dispersity, desirable optical properties and low cytotoxicity. These remarkable properties make the resultant AIE-active nanoprobes great potential for biomedical applications.

Aggregation-induced emission (AIE) dyes based fluorescent polymeric nanoparticles (FNPs) have been intensively explored for biomedical applications. However, many of these AIE-active FNPs are relied on the self-assembly of amphiphilic copolymers, which are not stable in diluted solution. Therefore, the introduction of cross-linkages into these micelles has demonstrated to be an efficient route to overcome this stability problem and endow ultra-low critical micelle concentrations (CMC) of these AIE-active FNPs. In this work, we reported the fabrication of cross-linked AIE-active FNPs through controllable reversible addition fragmentation chain transfer polymerization by using commercially available octavinyl-T8-silsesquioxane (8-vinyl POSS) as the cross-linkage for the first time. The resultant cross-linked amphiphilic copolymers (named as PEG-POSS-PhE) are prone to self-assemble into stable core-shell nanoparticles with well water dispersity, strong red fluorescence and low CMC (0.0069 mg mL(-1)) in aqueous solution. More importantly, PEG-POSS-PhE FNPs possess some other properties such as high water dispersity, uniform morphology and small size, excellent biocompatibility and cellular internalization, providing great potential of PEG-POSS-PhE FNPs for biological imaging application. (C) 2017 Elsevier B.V. All rights reserved.

The development of luminescent bioprobes based on organic dyes with aggregation-induced emission (AIE) characteristic has attracted great attention in recent years. In this work, we reported for the first time that AIE-active luminescent polymeric nanoparticles (LPNs) can be facilely prepared via a one-step acetalization reaction, which can be used to conjugate the aldehyde group containing AIE dye (PTH-CHO) and methoxypolyethylene glycols (mPEG-CHO) with a commercially available dendritic polyester (H40) using p-toluenesulfonic acid (TsOH) as the catalyst. As-prepared star-shaped hyperbranched luminescent polymers (named as H40-mPEG-mPTH) were prone to self-assemble into core-shell nanoparticles in aqueous solution because of their amphiphilic structure, in which hydrophobic components (such as PTH-CHO and H40) were encapsulated in the core while the hydrophilic components (mPEG-CHO) were acted as the shell. The final AIE-active H40-mPEG-mPTH LPNs displayed uniform spherical structure, strong fluorescence, excellent photostability and high water dispersity. Furthermore, biological evaluation results demonstrated that H40-mPEG-mPTH LPNs possess low toxicity and excellent biocompatibility, indicating their great potential for biomedical applications. Taken together, we reported a novel strategy for the construction of hyperbranched and biodegradable LPNs with AIE feature through a one-step acetalization reaction, which can be also utilized for construction of many other AIE-active LPNs with a variety structure and properties.

Fluorescent polymeric nanoparticles (FPNs) with aggregation-induced emission (AIE) property have received increasing attention and possess promising biomedical application potential in the recent years. Many efforts have been devoted to the fabrication methodologies of FPNs and significant advance has been achieved. In this contribution, a novel strategy for the fabrication of AIE-active amphiphilic copolymers is reported for the first time based on the Ce(IV) redox polymerization. As an example, ene group containing AIE-active dye (named as Phe-alc) is directly grafted onto a water soluble polymer polyethylene glycol (PEG) in H2 O/THF system under low temperature. Thus-obtained amphiphilic fluorescent polymers will self-assemble into FPNs with ultra-low critical micelle concentration, ultra-brightness, and great water dispersibility. Biological evaluation results suggest that the PEG-poly(Phe-alc) possess excellent biocompatibility and can be used for tracing their behavior in cells using confocal laser scanning microscope. These features make PEG-poly(Phe-alc) FPNs promising candidates for many biomedical applications, such as cell imaging, drug delivery vehicles, and targeted tracing. More importantly, many other functional groups can also be incorporated into these AIE-active FPNs through the redox polymerization. Therefore, the redox polymerization should be a facile and effective strategy for fabrication of AIE-active FPNs.

The mesoporous materials with large pore size, high specific surface area and high thermal stability have been widely utilized in a variety of fields ranging from environmental remediation to separation and biomedicine. However, surface modification of these silica nanomaterials is required to endow novel properties and achieve better performance for most of these applications. In this work, a new method has been established for surface modification of mesoporous silica nanoparticles (MSNs) that relied on the visible light induced atom transfer radical polymerization (ATRP). In the procedure, the copolymers composited with itaconic acid (IA) and poly(ethylene glycol)methyl acrylate (PEGMA) were grafted from MSNs using IA and PEGMA as the monomers and 10-Phenylphenothiazine(PTH) as the organic catalyst. The successful preparation of final polymer nanocomposites (named as MSNs-NH2-poly(IA-co-PEGMA)) were evidenced by a series of characterization techniques. More importantly, the anticancer agent cisplatin can be effectively loaded on MSNs-NH2-poly(IA-co-PEGMA) and controlled release it from the drug-loading composites with pH responsive behavior. As compared with conventional ATRP, the light induced surface-initiated ATRP could also be utilized for preparation of various silica polymer nanocomposites under rather benign conditions (e.g. absent of transition metal ions, low polymerization temperature and short polymerization time). Taken together, we have developed a rather promising strategy method for fabrication of multifunctional MSNs-NH2-poly(IA-co-PEGMA) with great potential for biomedical applications. (C) 2017 Elsevier B.V. All rights reserved.

Multicomponent reactions (MCRs) have recently received increasing attention for the synthesis of structural complexity in a single step from three or more reactants. They have also been considered as a powerful tool for the construction of sequence-controlled multifunctional polymers owing to their good substrate adaptability, simple operation and high efficiency. In this work, we reported methods that are a combination of the three-component mercaptoacetic acid locking imine (MALI) reaction and reversible addition fragmentation chain transfer (RAFT) polymerization in one pot to form luminescent organic nanoparticles (LONs) with aggregation-induced emission (AIE) features, high-brightness, great water dispersibility, ultra-small nanoscale size and excellent biocompatibility. In the reaction system, the MALI reaction and RAFT polymerization happened simultaneously in a "one-pot'' route. On the one hand, the AIE-active organic dye with one amino group ((Z)-3-(4-aminophenyl)-2-(10-hexadecyl-10H-phenothiazin-3yl) acrylonitrile) (named as Phe-NH2) was conjugated with an aldehyde-containing monomer (10-undecenal) by the MALI reaction, while the aldehyde-containing monomer was copolymerized with the hydrophilic monomer polyethylene glycol methyl methacrylate (PEGMA) through RAFT polymerization at the same time. Compared with other fabrication strategies, "one-pot'' strategies possess some advantages such as high efficiency, simplicity, and atom economy. On the other hand, due to the good applicability of RAFT polymerization and the MALI reaction, many other multifunctional AIE-active LONs could also be fabricated via adjusting the function of the substrates. Therefore, this strategy should be a general and important route for fabrication of AIE-active materials for different applications.

Fluorescent organic nanoparticles (FONs) have been regarded as the promising candidates for biomedical applications owing to their well adjustment of chemical structure and optical properties and good biological properties. However, the preparation of FONs from the natural derived polymers has been rarely reported thus far. In current work, we reported a novel strategy for preparation of FONs based on the self-polymerization of starch-dopamine conjugates and polyethyleneimine in rather mild experimental conditions, including air atmosphere, aqueous solution, absent catalysts and at room temperature. The morphology, chemical structure and optical properties of the resultant starch-based FONs were investigated by different characterization techniques. Biological evaluation results demonstrated that these starch-based FONs possess good biocompatibility and fluorescent imaging performance. More importantly, the novel strategy might also be extended for the preparation of many other carbohydrate polymers based FONs with different structure and functions. Therefore, this work opens a new avenue for the preparation and biomedical applications of luminescent carbohydrate polymers.

Carbon nanotubes (CNTs) are a type of one-dimensional carbon nanomaterials that possess excellent physicochemical properties and have been potentially utilized for a variety of applications. Surface modification of CNTs with polymers is a general route to expand and improve the performance of CNTs and has attracted great research interest over the past few decades. Although many methods have been developed previously, most of these methods still showed some disadvantages, such as low efficiency, complex experimental procedure and harsh reaction conditions etc. In this work, we reported a practical and novel way to fabricate CNTs based polymer composites via the combination of mussel inspired chemistry and reversible addition fragmentation chain transfer (RAFT) polymerization. First, the amino group was introduced onto the surface of CNTs via self-polymerization of dopamine. Then, chain transfer agent can be immobilized on the amino groups functionalized CNTs to obtain CNT-PDA-CTA, which can be utilized for surface-initiated RAFT polymerization. A water soluble and biocompatible monomer poly(ethylene glycol) monomethyl ether methacrylate (PEGMA) was adopted to fabricate pPEGMA functionalized CNTs through RAFT polymerization. The successful preparation of CNTs based polymer composites (CNT-pPEGMA) was confirmed by transmission electron microscopy, Fourier transform infrared spectroscopy, thermogravimetric analysis and X-ray photoelectron spectroscopy in details. The CNT-pPEGMA showed good dispersibility and desirable biocompatibility, making them highly potential for biomedical applications. More importantly, a large number of CNTs based polymer composites could also be fabricated through the same strategy when different monomers were used due to the good monomer adaptability of RAFT polymerization. Therefore, this strategy should be a general method for preparation of various multifunctional CNTs based polymer composites.

Fluorescent silica nanoparticles (FSNPs) have been extensively investigated for various biomedical applications in recently years. However, the aggregation of organic dyes in silica nanoparticles also leads the significant fluorescence quenching owing to the aggregation caused quenching effects of organic dyes. Herein, we developed a rather facile strategy to fabricate FSNPs with desirable fluorescent properties through non-covalent incorporation of fluorophores with aggregation-induced emission (ALE) feature into silica nanoparticles, which were subsequently modified with functional polymers. The resultant FSNPs polymer nanocomposites (named as FSNPs-poly(IA-co-PEGMA)) exhibited uniform spherical morphology, high water dispersiity, and bright red fluorescence. Cytotoxicity results indicate that FSNPs-poly(IA-co-PEGMA) possess excellent biocompatibility. Cell uptake behavior suggests FSNPs-poly(IA-co-PEGMA) are of great potential for biological imaging applications. Taken together, we have reported a facile method for the fabrication of FSNPs through non-covalent encapsulation using an AIE-active dye. These FSNPs can be further functionalized with functional polymers through ring-opening reaction and the resultant FSNPs-poly(IA-co-PEGMA) showed great potential for biological imaging. More importantly, we believe that many other functional components could also be integrated into these FSNPs through the facile ring-opening reaction. Therefore, this method should be a facile and general tool for fabrication of polymer functionalized AIE-active FSNPs. (C) 2017 Elsevier B.V. All rights reserved.