Coupling BCP Ceramics with Micro-Vibration Stimulation Field for Cascade Amplification from Immune Activation to Bone Regeneration

The osteoimmunology has revealed that immune system plays an important role in maintaining bone metabolism and remodeling. As long-term physiological factor in bone, mechanical stimulation such as micro-vibration stimulation (MVS) exerts effects on regulating osteogenesis and immune response. In this study, the osteo-immunodulatory effects of bicalcium phosphate (BCP) ceramics coupled with MVS are investigated. This results find that the combination of BCP ceramics and MVS may exert synergistic effects on the polarization and functional status of macrophages through activating plasma membrance Ca²⁺ ATPase (PMCA) channel, reducing the intracellular calcium ion concentration, and inhibiting downstream extracellular signal-regulated kinase (ERK)1/2 signaling pathway. BCP ceramics coupled MVS could drive the macrophage polarization to wound-healing M2 phenotype to decrease the production of pro-inflammatory factors, enhance the secretion of anti-inflammatory cytokines and growth factors such as transforming growth factor (TGF)-β1 and bone morphogenetic protein (BMP)-2. Moreover, BCP and MVS-modulated macrophage secretion pattern can trigger the BMP/TGF-Smad signaling pathways to induce osteoblastic differentiation of bone marrow mesenchymal stromal cells (BM-MSCs) in vitro, and maintain cellular viability and promote the formation of collagen-rich osteoid like tissues and mature blood vessels in vivo. This study demonstrates that the introduction of mechanical stimuli like non-invasive MVS is an effective strategy to improve bone repair effects of biomaterials through endowing them with superior osteo-immunodulatory capacity.     

Electrodeposition on nanofibrous polymer scaffolds: Rapid mineralization, tunable calcium phosphate composition and topography

We developed a straightforward, fast, and versatile technique to fabricate mineralized nanofibrous polymer scaffolds for bone regeneration in this work. Nanofibrous poly(l-lactic acid) scaffolds were fabricated using both electrospinning and phase separation techniques. An electrodeposition process was designed to deposit calcium phosphate on the nanofibrous scaffolds. Such scaffolds contain a high quality mineral coating on the fiber surface with tunable surface topography and chemical composition by varying the processing parameters, which can mimic the composition and structure of natural bone extracellular matrix and provide a more biocompatible interface for bone regeneration.     

Programmable Electrofabrication of Porous Janus Films with Tunable Janus Balance for Anisotropic Cell Guidance and Tissue Regeneration

Janus films with controlled pore structures can be particularly important in diverse applications. There remains a challenge for simple, rapid, and scalable fabrication methods to control Janus balance (JB) including the thickness of the individual face as well as porosity and pore size. Here the electrofabrication of a porous Janus film with controlled Janus balance from aminopolysaccharide chitosan under the salt effect is reported. Sequential deposition of chitosan under programmable salt environment and electrochemical conditions enables construction of Janus films with precisely controlled Janus balance. Bioactive partially soluble calcium phosphate (CaP) salts can also generate porous structure in Janus film. It is specifically reported that a chitosan/hydroxyl apatite (HAp) composite Janus film can serve as an effective scaffold for guided bone regeneration. The dense layer functions to provide mechanical support and serves as a barrier for fibrous connective tissue penetration. The porous composite layer functions to provide the microenvironment for osteogenesis. In vivo studies using a rat calvarial defect model confirm the beneficial features of this Janus composite for guided bone regeneration. These results suggest the potential of electrofabrication as a simple and scalable platform technology to tune the self‐organization of soft matter for a range of emerging applications.     

原材料物理化学特性对多孔性PTC陶瓷结构与性能的影响

本文研究了以不同物理化学形态的含结晶水有机酸盐草酸氧钛钡为原料时，对多孔性ＰＴＣ陶瓷的结构与性能的影响；以及同时以不同结晶水含量的草酸氧钛钡为主原料时，二者分别对同一块多孔性ＰＴＣ陶瓷的不同结构特征、不同性能特征做出的不同贡献。     

纳米铁掺杂先驱体转化SiC多孔陶瓷的电磁吸波性能研究

先驱体转化法中,由于材料的分子具有可设计、成型方便、低温裂解转化为陶瓷的特点,在陶瓷材料的制备中表现出极大的优势。文中运用功率超声将平均粒径30 nm的超细金属铁粉均匀分散到聚碳硅烷中,通过先驱体转化工艺制备了一种多孔介电陶瓷。采用SEM分析了陶瓷的微观形貌,用XRD研究了陶瓷中铁元素的存在状态;表征了陶瓷材料的电磁吸波性能,并考察了纳米铁粉含量对材料电磁性能的影响。     

Calcium Phosphate Mineralized Black Phosphorous with Enhanced Functionality and Anticancer Bioactivity

Biodegradable inorganic nanomaterials have opened new perspectives for cancer therapy due to their inherent anticancer activity. Black phosphorus nanosheets (BPs) with their unique bioactivity have recently been identified as promising cancer therapeutic agents but their application is hampered by the difficulty in surface functionalization. Herein, an in situ calcium phosphate (CaP) mineralization strategy is described to enhance the anticancer activity of BPs. By using BPs as the phosphate sources and growth templates, the synthesized CaP‐mineralized BPs (CaBPs) retain the intrinsic properties of BPs and at the same time have high loading capacities for various fluorophores to enable effective bioimaging and tracing. Compared to BPs, CaBPs exhibit enhanced and selective anticancer bioactivity due to the improved pH‐responsive degradation behavior and intracellular Ca²⁺ overloading in cancer cells. Furthermore, CaBPs specifically target mitochondria and cause structural damage, thus leading to mitochondria‐mediated apoptosis in cancer cells. After intravenous injection, CaBPs target orthotopic breast cancer cells to inhibit tumor growth without giving rise to adverse effects or toxicity. The results demonstrate the great potential of CaBPs as targeted anticancer agents and the CaP mineralization approach provides a versatile surface functionalization strategy for nanotherapeutic agents.     

High‐Performance Epoxy Nanocomposites Reinforced with Three‐Dimensional Carbon Nanotube Sponge for Electromagnetic Interference Shielding

Light‐weight and high‐performance electromagnetic interference (EMI)‐shielding epoxy nanocomposites are prepared by an infiltration method using a 3D carbon nanotube (CNT) sponge as the 3D reinforcement and conducting framework. The preformed, highly porous, and electrically conducting framework acts as a highway for electron transport and can resist a high external loading to protect the epoxy nanocomposite. Consequently, a remarkable conductivity of 148 S m^?1 and an outstanding EMI shielding effectiveness of around 33 dB in the X‐band are achieved for the epoxy nanocomposite with 0.66 wt% of CNT sponge, which is higher than that achieved for epoxy nanocomposites with 20 wt% of conventional CNTs. More importantly, the CNT sponge provides a dual advantage over conventional CNTs in its prominent reinforcement and toughening of the epoxy composite. Only 0.66 wt% of CNT sponge significantly increases the flexural and tensile strengths by 102% and 64%, respectively, as compared to those of neat epoxy. Moreover, the nanocomposite shows a 250% increase in tensile toughness and a 97% increase in elongation at break. These results indicate that CNT sponge is an ideal functional component for mechanically strong and high‐performance EMI‐shielding nanocomposites.     

Oxidation‐Resistant and Elastic Mesoporous Carbon with Single‐Layer Graphene Walls

An oxidation‐resistant and elastic mesoporous carbon, graphene mesosponge (GMS), is prepared. GMS has a sponge‐like mesoporous framework (mean pore size is 5.8 nm) consisting mostly of single‐layer graphene walls, which realizes a high electric conductivity and a large surface area (1940 m² g^?1). Moreover, the graphene‐based framework includes only a very small amount of edge sites, thereby achieving much higher stability against oxidation than conventional porous carbons such as carbon blacks and activated carbons. Thus, GMS can simultaneously possess seemingly incompatible properties; the advantages of graphitized carbon materials (high conductivity and high oxidation resistance) and porous carbons (large surface area). These unique features allow GMS to exhibit a sufficient capacitance (125 F g^?1), wide potential window (4 V), and good rate capability as an electrode material for electric double‐layer capacitors utilizing an organic electrolyte. Hence, GMS achieves a high energy density of 59.3 Wh kg^?1 (material mass base), which is more than twice that of commercial materials. Moreover, the continuous graphene framework makes GMS mechanically tough and extremely elastic, and its mean pore size (5.8 nm) can be reversibly compressed down to 0.7 nm by simply applying mechanical force. The sponge‐like elastic property enables an advanced force‐induced adsorption control.     

BaCu(B2O5)的添加对Li2MgTi3O8微波介质陶瓷性能的影响

采用传统固相反应法制备Li2MgTi3O8微波介质陶瓷,研究了BaCu(B2O5)(简称BCB)的添加对Li2MgTi3O8微波介质陶瓷的烧结性能及介电特性的影响.结果表明:BCB作为低熔点氧化物烧结助剂,可有效降低所制陶瓷烧结温度,而且可以调节τf近零.当添加质量分数3％的BCB,900℃烧结所制陶瓷的综合微波介电性...     

Sr0.3Ba0.7Nb2-yZryO6-y/2陶瓷的微观结构和介电性能研究

采用传统固相法制备了Sr0.3 Ba0.7Nb2-yZryO6-y/2(SBNZ)(0≤y≤0.50)陶瓷.研究了Zr掺杂对SBNZ陶瓷微观结构和介电性能的影响.结果表明:y≤0.10时,Zr固溶到SBNZ晶体结构,使陶瓷晶格发生畸变并引起晶粒异常长大;y=0.30时,第二相Ba3ZrNb4O15的生成抑制了晶粒的异常...     

CuO/CeO_2共掺杂Ba_(0.85)Ca_(0.15)Zr_(0.1)Ti_(0.9)O_3无铅压电陶瓷性能研究

采用固相反应法制备了CuO、CeO2共掺杂Ba0.85Ca0.15Zr0.1Ti0.9O3(BCZT)无铅压电陶瓷,研究了CuO的掺杂量对所制陶瓷晶体结构、压电及介电性能的影响。结果表明:CuO的加入,进一步降低了预先经0.05%(质量分数)CeO2掺杂的BCZT陶瓷的烧结温度;在1 250℃烧结时,仍可获得纯钙钛矿结构的BCZT陶瓷。当CuO掺杂量为质量分数0.2%时,所制BCZT陶瓷具有最佳的压电性能:d33=370 pC/N,tC约为93℃,tanδ=0.0147。     

Kaolinite as a Suspending Agent for Preparation of Porous BaTiO3 Ceramics via Freeze Casting

Porous barium titanate (BT) ceramics were fabricated by a freeze-casting technique with kaolinite as a suspending agent, and the effects of the kaolinite content on the microstructure and dielectric properties were investigated. The porous BT ceramics possessed high porosity and a unique two-dimensional pore structure along the freezing direction. The absolute value of the zeta potential and the viscosity of the slurry increased with increasing kaolinite content. The zeta potential plot and viscosity characterization results showed that a stable slurry was obtained when the kaolinite content was 8 wt.%. The porosity was substantially affected by the suspension effect and the fluxing action of the kaolinite. Porosity characterization showed that the porosity of the porous BT ceramic reached a maximum value for 8 wt.% addition of kaolinite. Scanning electron microscopy showed that the porous BT ceramics possessed a multilayered channel structure. The temperature dependence of the permittivity showed that the porous BT ceramics possessed good temperature stability of the dielectric constant.     

添加MgLiSi玻璃对BNT陶瓷介电性能的影响

采用传统固相反应法,制备了钨青铜结构BaO·Nd2O3·4TiO2(BNT)陶瓷,并添加质量分数为1%～6%的MgO·Li2O·SiO2(MgLiSi)玻璃。对其显微结构和介电性能进行了研究。结果表明:在BNT陶瓷中添加适量的MgLiSi玻璃,可以使BNT陶瓷的烧结温度从1250℃以上降低到1150℃,并提高其介电性能。当添加质量分数为4%的MgLiSi玻璃时,BNT陶瓷可获得最佳的介电性能:εr=95,tanδ=5×10–4,击穿场强为16.7×103V/mm。     

Ferroelectric ceramic electrooptic materials and devices

Thin polished plates of hot-pressed rhombohedral lead zirconate-lead titanate ceramics possess one of two types of electro-optic properties depending on the nominal grain diameter. In poled coarse-grained ceramics the electrooptic effect of importance for devices is the dependence of the light scattering properties on the orientation of the ceramic polar axis (electrical poling direction). The light scattering properties are essentially independent of the magnitude of electrical poling (ferroelectric remanence state). Poled fine-grained ceramics are birefringent, and their light transmission characteristics are similar to those of optically uniaxial crystals. These materials exhibit orthotropic symmetry with respect to the optic axis, which coincides with the ceramic polar axis. The fine-grained ceramic electrooptic effect of primary importance for devices is the dependence of the effective birefringence on the magnitude of electrical poling as well as on the intensity of the applied biasing electric field. Retardation of a ceramic plate can be varied incrementally by partial switching or continuously by application of a nonswitching bias field. Both coarse- and fine-grained ceramics have the property that localized areas as small as 25 µ by 25 µ can be poled or switched independently without affecting the light transmission characteristics of the surrounding area. The locally switched areas are stable with time, but they can be "erased" by switching them back to their original orientation. Each locally switched area can function as a light shutter, valve, or spectral filter depending on the ceramic material, the switching mode, and the characteristics of the incident light.     

Biomimetic and Superwettable Nanofibrous Skins for Highly Efficient Separation of Oil‐in‐Water Emulsions

Developing a feasible and efficient separation membrane for the purification of highly emulsified oily wastewater is of significance but challenging due to the critical limitations of low flux and serious membrane fouling. Herein, a biomimetic and superwettable nanofibrous skin on an electrospun fibrous membrane via a facile strategy of synchronous electrospraying and electrospinning is created. The obtained nanofibrous skin possesses a lotus‐leaf‐like micro/nanostructured surface with intriguing superhydrophilicity and underwater superoleophobicity, which are due to the synergistic effect of the hierarchical roughness and hydrophilic polymeric matrix. The ultrathin, high porosity, sub‐micrometer porous skin layer results in the composite nanofibrous membranes exhibiting superior performances for separating both highly emulsified surfactant‐free and surfactant‐stabilized oil‐in‐water emulsions. An ultrahigh permeation flux of up to 5152 L m^?2 h^?1 with a separation efficiency of >99.93% is obtained solely under the driving of gravity (≈1 kPa), which was one order of magnitude higher than that of conventional filtration membranes with similar separation properties, showing significant applicability for energy‐saving filtration. Moreover, with the advantage of an excellent antioil fouling property, the membrane exhibits robust reusability for long‐term separation, which is promising for large‐scale oily wastewater remediation.     

BaWO4掺杂对BMT陶瓷介电性能的影响

采用传统电子陶瓷工艺合成了BaWO4掺杂的Ba(Mg1/3Ta2/3)O3( BMT)微波介质陶瓷,研究了质量分数w(BaWO4)从2％～8％变化对BMT微波介质陶瓷结构和微波特性的影响.实验结果表明:添加少量的BaWO4能明显改善BMT陶瓷的烧结性能,当w(BaWO4)=4％时,BMT陶瓷的烧结温度由纯相时的1650...     

Ba_(0.6)Sr_(0.4)TiO_3/ZnNb_2O_6复相陶瓷的显微结构和介电性能

采用传统电子陶瓷工艺制备了Ba_(0.6)Sr_(0.4)TiO_3/ZnNb_2O_6(BSTZ)复相陶瓷,研究了ZnNb_2O_6含量对BSTZ陶瓷结构和介电性能的影响规律.结果表明,BSTZ复相陶瓷可在较低温度下烧结成瓷;陶瓷中除了Ba_(0.6)Sr_(0.4)TiO_3和ZnNb_2O_6两种主晶相,还有新相BaNb_(3.6)O_(10)生成;陶瓷的介电常数和介电损耗均随ZnNb2O6含量的增加而降低;当x(ZnNb_2O_6)=0.6(摩尔比)时,复相陶瓷在微波下的介电常数为74,介电损耗为0.043,可调性可达10.54%(1.0 kV/mm).     

稀土元素Pr替位改性的高温CaBi_2Nb_2O_9压电陶瓷

采用普通陶瓷工艺制备了由稀土元素Pr替位改性的高温Ca1-xPrxBi2Nb2O9(x=0～0.100)无铅压电陶瓷,研究了Pr含量对CaBi2Nb2O9(CBNO)压电陶瓷介电及压电性能的影响。结果表明:Pr对Ca的替换明显提高了CBNO压电陶瓷的压电性能。其中,Pr含量x为0.050的Ca0.95Pr0.05Bi2Nb2O9压电陶瓷表现出最好的压电性能,其压电常数d33高达14pC/N,且在800℃以下表现出良好的温度稳定性。     

K+对ZnO压敏陶瓷电性能的影响

采用传统的陶瓷工艺,制备了ZnO压敏陶瓷。研究了K+掺杂量对ZnO压敏陶瓷电性能的影响。结果表明:当x(K+)小于40×10–6时,对其电性能几乎没有影响;但若x(K+)超过60×10–6后,由于K+在晶界和三角区的大量偏析,破坏了晶界层的稳定,导致其浪涌电流耐受能力严重劣化。     

Performance Enhancement of Flexible Piezoelectric Nanogenerator via Doping and Rational 3D Structure Design For Self‐Powered Mechanosensational System

With the rapid development of the Internet of things (IoT), flexible piezoelectric nanogenerators (PENG) have attracted extensive attention for harvesting environmental mechanical energy to power electronics and nanosystems. Herein, porous piezoelectric fillers with samarium/titanium‐doped BiFeO₃ (BFO) are prepared by a freeze‐drying method, and then silicone rubber is filled into the microvoids of the piezoelectric ceramics, forming a unique structure based on silicone rubber matrix with uniformly distributed piezoelectric ceramic. When subjected to external force stimulation, compared with conventional piezocomposite films found on undoped BFO without a porous structure, the PENG possesses higher stress transfer ability and thus boosts output performance. The notable enhancement in the stress transfer ability and piezoelectric potential is proven by COMSOL simulations. The PENG can exhibit a maximum open‐circuit voltage (V_oc) of 16 V and short‐circuit current (I_sc) of 2.8 µA, which is 5.3 and 5.6 times higher than those of conventional piezocomposite films, respectively. The PENG can be used as a triggering signal to control the operation of fire extinguishers and household appliances. This work not only expands the application scope of lead‐free piezoelectric ceramic for energy harvesting, but also provides a novel solution for self‐powered mechanosensation and shows great potential application in IoT.