Degradable magnesium-hydroxyapatite interpenetrating phase composites processed by current assisted metal infiltration in additive-manufactured porous preforms

This work explores ceramic additive manufacturing in combination with liquid metal infiltration for the production of degradable interpenetrating phase magnesium/hydroxyapatite(Mg/HA) composites. Material extrusion additive manufacturing was used to produce stoichiometric,and calcium deficient HA preforms with a well-controlled open pore network, allowing the customization of the topological relationship of the composite. Pure Mg and two different Mg alloys were used to infiltrate the preforms by means of an advanced liquid infiltration method inspired by spark plasma sintering, using a novel die design to avoid the structural collapse of the preform. Complete infiltration was achieved in 8 min, including the time for the Mg melting. The short processing time enabled to restrict the decomposition of HA due to the reducing capacity of liquid Mg. The pure Mg-base composites showed compressive yield strength above pure Mg in cast state. Mg alloy-based composites did not show higher strength than the bare alloys due to grain coarsening, but showed similar mechanical properties than other Mg/HA composites that have significantly higher fraction of metallic phase. The composites showed faster degradation rate under simulated body conditions than the bare metallic component due to the formation of galvanic pairs at microstructural level. Mg dissolved preferentially over HA leaving behind a scaffold after a prolonged degradation period. In turn, the fast production of soluble degradation products caused cell metabolic changes after 24 h of culture with not-diluted material extracts. The topological optimization and reduction of the degradation rate are the topics for future research.

3D direct writing and micro detonation of CL-20 based explosive ink containing O/W emulsion binder

The booming development of DIW technology present an unprecedented prospect in energetic materials field and has attracted great interest due to its relative simplicity and high flexibility of manufacturing.Herein,a novel CL-20 based explosive ink formulation have been developed successfully for MEMS initiation systems via DIW technology.We designed PVA/GAP into an oil-in-water(O/W)emulsion,in the way that the aqueous solution of PVA as water phase,the ethyl acetate solution of GAP as oil phase,the combination of Tween 80 and SDS as emulsifier,BPS as a curing agent of GAP.The ideal formulation with good shear-thinning rheology properties and clear gel point was prepared using only 10 wt%emulsion.The dual-cured network formed during the curing process made the printed sample have good mechanical properties.The printed samples had satisfactory molding effect without cracks or fractures,the crystal form of CL-20 not changed and the thermal stability have improved.Deposition of explosive inks via DIW in micro-scale grooves had excellent detonation performances,which critical detonation size was 1×0.045 mm,detonation velocity was 7129 m/s and when the corner reaching 150°can still detonated stably.This study may open new avenues for developing binder systems in explosive ink formulations.

Microstructure formation mechanism of catalyst layer and its effect on fuel cell performance:Effect of dispersion medium composition

The design of the catalyst layer(CL)offers a feasible way to realize the commercialization of proton exchange membrane fuel cells(PEMFCs).An in-depth understanding of catalyst inks is critical to achieving the optimal CL structure and cell performance.In this work,the effects of the solvent evaporation process during ink drying on the formation of the CL microstructure are particularly considered to reveal the structure-property correlations among the catalyst ink,drying process,CL microstructure and fuel cell performance.An increase in the alcohol content of the catalyst ink increases the amount of free ionomers while allowing the ionomer backbone to be more stretched in the dispersion medium.The higher alcohol content contributes to rapid solvent evaporation and thus inhibits the formation of coffee rings;as a result,a more developed ionomer network with a denser pore structure is obtained.Therefore,the alcohol-rich electrode exhibits better proton conduction capability,but higher oxygen transport resistance.For complex fuel cell operating conditions,a catalyst ink formulation with 50 wt%alcohol content is preferred due to its proper ionomer and pore size distribution,providing satisfactory fuel cell performance.

Elemental Quantification in Intradermal Tattoo-Inks by Means of Total Reflection X-Ray Fluorescence

This work describes the application of a detailed set of TXRF evaluations to the elemental content of assorted tattoo inks, on the market of the city of Concepcion, Chile. We applied TXRF as a screening method for determining the composition in 3 sets of tattoo inks, in order to establish, from an inorganic point of view, the composition and purity of the samples, evaluating their elemental innocuousness. The analyzed 48 products were freely acquired from on line suppliers. All of them were analyzed by external standard quantification, but in order to inter-compare the results, a 15% of the samples were acidly digested and then quantified by the internal standard method. In the samples we determined: 1) their inorganic quantitative composition and, 2) the possible presence of elements which are potential health hazards. In this study few anomalies were found: 1) The high presence Ti of and W in few samples, 2) Arsenic was found in four of them, and 3) A trace detection of a rare earth element in a particular product. The products studied are almost freely imported from a world open marked, so the questions about their innocuousness could affect not only to the Chilean society.

3D打印生物墨水在组织修复与再生医学中的应用

背景:通过选用合适的生物墨水,3D打印技术可用以制造人体组织和器官的代替物,并在人体内发挥作用。近些年来3D打印技术发展迅速,在再生医学中有着巨大的应用潜力。目的:介绍3D打印用生物墨水的类型,并综述生物墨水的分类、应用、优缺点及未来愿景。方法:以“3D printing,Biological ink,Tissue engineering,hydrogel,Synthetic material,Cytoactive factor,3D打印、生物墨水、组织工程”为检索词,运用计算机检索2000-2022年以来发表在PubMed、CNKI数据库中的相关文献,最终纳入83篇进行综述。结果与结论:在过去的几十年里,生物3D打印技术发展迅速,在组织工程和生物医学等各个领域都受到了极大的关注。相对于传统生物支架制造方法在功能性及结构方面受到的限制,3D打印可以更好地模拟生物组织复杂的结构,并且具有合适的力学、流变学和生物学特性。生物墨水是3D打印中必不可少的一部分,通过生物材料制备的生物墨水,经打印后产生的生物支架在组织修复和再生医学等方面有着巨大的科研潜力及临床意义,其材料的研究本身也越来越受到专家们的重视。3D打印生物墨水的材料各种各样,有天然材料也有合成材料,还有一些不需要任何额外生物材料的细胞聚集体,并且各种材料在实际运用中的功效各不相同。未来会有越来越多的生物墨水被研制用于组织工程,需要通过充足的实验模拟及设备测试来对生物墨水的可打印性进行分析,从而满足实际的医用需求。

3D printing of flexible piezoelectric composite with integrated sensing and actuation applications

3D printing of flexible piezoelectric composites(3D-FPCs)is increasingly attracting the attention due to its unique advantage for customized smart applications.However,current research mainly focuses on the 0-3 piezoelectric composites,in which the piezoelectric ceramics are embedded in polymer matrix in the form of particles.The poor connectivity between particles much reduces the conduction of strain and charge in the composites,seriously limiting its application in actuation.In this work,a continuous lead zirconate titanate(PZT)double-layer ceramic scaffold was prepared by 3D printing and assembled with epoxy resin and interdigital electrodes together to manufacture a multifunctional device.The 3D-FPCs exhibit a free strain of 1830 ppm in actuating and are able to actuate a stainless-steel cantilever beam to produce a tip displacement of 5.71 mm.Additionally,the devices exhibit a sensitivity of 26.81V/g in sensing applications.Furthermore,3D-FPCs are demonstrated as actuators for mobile small robots and wearable sensors for sensing joint activities.

非接触点胶打印用ZnO-SnO_(2)复合气敏墨水的制备及气敏性能研究

非接触点胶打印是一种新型、高精度、无模板、低成本的成膜技术,墨水的理化性质是决定打印薄膜质量的关键,对微电子器件性能有着重要影响。本文采用聚乙二醇400(PEG400)作为分散剂取代传统的高分子量分散剂,以乙二醇和丙三醇为溶剂、ZnO-SnO_(2)复合气敏材料为功能相制备高性能气敏墨水,并利用非接触点胶技术在基于微电子机械系统(MEMS)的微热板上打印ZnO-SnO_(2)复合气敏薄膜。根据墨水的黏度及悬浮稳定性,分析了PEG400含量和固含量对墨水理化性质的影响,通过SEM观察薄膜的微观形貌,研究结果表明,当固含量为15%(质量分数,下同)、PEG400含量为6%时,复合气敏墨水具备可打印性及低温烧结成膜特性,制备的复合气敏薄膜厚度均匀,表面平整,边缘规整,对丙酮气体有良好的响应。

Preparation and combustion properties of laminated sticks of B-CuO and B-Bi_(2)O_(3)

To explore the composite process of B-CuO and B-Bi_(2)O_(3) two-component laminated sticks,obtain the corresponding sticks with good printing effect,and explore the energy release behavior.In this study,boron,copper oxide,and bismuth trioxide powders were dispersed in the dispersed phase (DMF) using F_(2602) as a binder,and the construction of two-component B-CuO,B-Bi_(2)O_(3),three-component microcomposite,and three-component macro-composite sticks were realized with the help of double nozzle direct ink writing (DIW) technique respectively.The resulting sticks were ignited by a nichrome wire energized with a direct current,and a high-speed camera system was used to record the combustion behavior of the sticks,mark the flame position,and calculate the rate of ignition.The results showed that the B-CuO stick burning rate (42.11 mm·s^(-1)) was much higher than that of B-Bi_(2)O_(3)(17.84 mm·s^(-1)).The formulation with the highest CuO content (ω_(CuO)=58.7%) in the microscale composite of the sticks also had the fastest burning rate of 60.59 mm·s^(-1),as the CuO content decreased (ω_(CuO)=43.5%,29.3%),its burning rate decreased to 34.78 mm·s^(-1),37.97 mm·s^(-1).The stick with the highest copper oxide content(ω_(CuO)=60%) also possessed the highest burning rate (48.84 mm·s^(-1)) in the macro-composite sticks,and the burning rates of the macro-composite sticks with component spacing of 0.1 mm,0.2 mm,and 0.5 mm were 43.34 mm·s^(-1),48.84 mm·s^(-1),and 40.76 mm·s^(-1).

Extrusion-base d 3D-printe d“rolle d-up”composite scaffolds with hierarchical pore structure for bone growth and repair

Three-dimensional(3D)bioprinting,specifically direct ink writing(DIW)capable of printing biologically active substances such as growth factors or drugs under low-temperature conditions,is an emerging di-rection in bone tissue engineering.However,limited by the bio-ink mobility and the poor resolution of this printing technology,the lateral pores of current crisscross-stacked scaffolds printed through DIW tend to clog and are inimical to bone growth.Therefore,it is critical to develop DIW printed biologi-cal scaffold structure with high mechanical strength,porosity,and biocompatibility performance.Herein,patterned polylactic acid(PLA)/polycaprolactone(PCL)/nano-hydroxyapatite(n-HA)based scaffold was printed through DIW technological and rolled-up for properties characterization,cytocompatibility test,and bone repair experiment.The result not only shows that the hexagonal patterned scaffolds are me-chanically strong with porosity,but also demonstrated that the hierarchical pore structure formed during rolled-up has the potential to address the clogging problem and stimulates bone growth and repair.

石墨烯-银纳米粒子复合墨水的制备及直写打印研究

高性能导电墨水的研究与开发是实现印刷电子器件不断发展的关键。石墨烯的二维结构使其本身具有良好的柔性和导电性,但由于片层间范德华力的相互作用使其容易发生团聚和堆积,通过复合的方式引入金属纳米粒子,既可以防止发生团聚又可以降低石墨烯片层间的接触电阻,使复合材料的导电性增强。鉴于此,本工作采用原位化学还原的方法制备石墨烯(rGO)和银纳米粒子(AgNPs)组成的复合墨水,以实现AgNPs在rGO纳米片层上的均匀分布。通过直写打印技术将墨水打印在基底上,得到的印刷图案具有优异的导电性,典型的电阻率为1.48×10^(-6)Ω·m。经过数百次弯曲循环后,印刷图案的电阻值仅略有增加,表明图案具有极佳的稳定性和机械柔韧性。这对于印刷电子器件的发展具有重要意义。

中国近现代古法制作墨锭的检测与分析

本工作以中国近现代古法制作墨锭为研究对象,采用元素分析、X-射线荧光光谱分析(XRF)、热重分析(TGA)、透射电子显微镜分析(TEM)、动态光散射分析(DLS)及接触角测试等多种表征方法,分别对墨块本体及其表面描金部分的元素组成,墨锭的烟、胶以及其他添加剂的成分配比,墨颗粒微观形貌及单分散尺寸,墨颗粒聚集状态及尺寸,墨锭表面的亲疏水性等进行了测定,系统研究了几种不同工艺的传统中国墨锭的性质、性能特点。结果表明,不同墨锭在元素组成、成分配比以及微观尺寸、墨颗粒聚集状态、表面亲疏水性上存在一定的规律性。对墨锭物理化学性质的科学检测与分析,可以为中国传统墨锭的科学检测基础数据库提供数据支持,而通过对其具体关联与差异的研究,还可与制墨工艺、墨的品质相关联,为墨的使用、保存和鉴别提供科学依据,为墨的写印效果研究提供参考。

中国古墨与现代墨元素成分研究

对中国古墨（汉墨、明墨与清墨）与不同产地的现代墨元素成分作了对比分析。用离子背散射测定墨中常量元素C、N、O的含量，用质子激发X荧光法测定微量元素K、Ca、Ti、Cu、Fe等10种元素的含量。实验结果表明，古墨中微量元素K、Ca的含量比现代徽墨、沪墨高10倍以上，而现代徽墨与沪墨中元素N和An的含量也有明显的差别。

超声波对鱿鱼墨黑色素成分和物理结构的影响

为了提高鱿鱼综合利用价值,以加工废弃物中的鱿鱼墨黑色素为原料,研究超声波处理对黑色素成分和物理结构的影响。采用超声功率15 W/mL、超声时间2 s、间歇时间1 s、总工作时间20 min的工作条件对黑色素进行处理。结果表明:鱿鱼墨黑色素在超声波处理后,波长为224 nm和267 nm附近的两个峰吸光值显著增加,黑色素在环己烷中的溶解性显著增加,样品中没有新的具有紫外可见吸收特性物质生成;黑色素中蛋白质在超声波处理后的没有发生显著变化,而脂质含量显著减少;超声波后Ca、Mg、Na、K、Fe、Cu、Cd和Pb等8种金属元素含量均显著降低;电镜图片显示黑色素微球颗粒在超声过程中发生了爆炸,产生更为细小的碎片和碎末。

金乌贼墨汁营养成分分析及评价

采用氨基酸自动分析仪、原子吸收仪、液相色谱及常规化学分析法对金乌贼 (Sepiaesculenta)墨汁的基本营养组分以及氨基酸、矿物质元素、维生素的组成和含量进行了测定。在所检测的 1 7种氨基酸中 ,含有 7种必需氨基酸和 2种半必需氨基酸。同时富含Mg、Ca、K、Na等常量矿物元素以及Fe、Sr、Al等微量元素和脂溶性。

墨的药学研究概况

在广泛文献检索基础上,文章概述了墨的制造、成分、药理、临床应用价值,为其深入研究开发提供一些理论依据。

油墨刮刀电刷镀层厚度与刷镀工艺参数关系的数学模型

油墨刮刀表面强化层的厚度是影响刮刀制作质量的重要因素,目前国内这方面的研究尚不深入。应用电刷镀方法对传统刮刀进行镀覆,分析了电刷镀工艺参数对油墨刮刀镀层厚度的影响。采用中心组合设计法和响应面法,建立了镀层厚度与刷镀电压及镀头运动速度之间的数学模型。结果表明:刷镀层厚度随电压的增大而增大,随镀头运动速度的增大而减小;在刷镀过程中可以根据该模型控制电压,动态优化镀头运动速度,实现镀层厚度的均匀化和精确控制。

数码喷墨印花技术综述

近年来,数码喷墨印花技术在纺织品中的应用日益受到国内外的广泛关注。文章扼要介绍了纺织品数码喷墨印花技术的组成元素、工艺过程、技术特点、应用领域以及发展前景,指出喷墨印花技术将成为21世纪纺织品印花发展的必然趋势。

复合食品包装材料的安全性研究

介绍了复合食品包装材料中的几种主要有毒有害物质,包括添加剂、油墨、黏合剂等,并从标准制定、市场监管、科研投入、企业和消费者的责任等方面提出了加强复合食品包装材料安全性的对策,为复合食品包装材料的质量安全控制提供参考。

助剂在PVC木塑底涂油墨中的应用

颜料在油墨中的润湿分散对PVC木塑底涂油墨性能有重要影响.应用BYK分散助剂可以制备分散和储存稳定性能优异的单色油墨,并有效解决了复色油墨的抗浮色发花能力,同时还考察了流平剂对PVC木塑底涂油墨性能的影响.

氯化PP/氯化EVA在塑料复合油墨中的应用

介绍了新型粘合牢度高的氯化PP 氯化EVA粘合剂在复合油墨中的效能。与单独使用氯化PP的油墨相比,配合应用氯化PP与氯化EVA的塑料复合油墨印刷到BOPP薄膜后粘接性强,且低温使用时剥离强度、分散性、溶剂的释放性等指标显著提高。