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The past decade has witnessed the rapid development of perovskite solar cells, with their power conversion efficiency increasing from an initial 3.8% to over 26%, approaching the Shockley-Queisser (S-Q) limit for single-junction solar cells. Multijunction solar cells have garnered significant attention due to their tremendous potential to surpass the S-Q limit by reducing thermalization losses and wide light harvesting. The wide bandgap tunability of metal halide perovskite materials makes them highly suitable for sub-cells in tandem solar cells (TSCs). Currently, LONGi Green Energy Technology Co., Ltd. in China has set a world record efficiency of 34.6% based on a dual-junction perovskitesilicon TSCs, far surpassing the single-junction efficiencies of each sub-cell. Consequently, perovskite based TSCs are widely regarded as the next-generation photovoltaic products in the solar industry. Despite the significant efficiency improvements, several challenges still impede the commercial application of perovskite based TSCs, such as the instability of perovskite materials and difficulties in achieving large-scale production. This review summarizes the progresses and optimization strategies of perovskite based TSCs. This review also identifies the critical issues hindering multijunction solar cells. Finally, the potential solutions to address these challenges are proposed to advance the development of perovskite based TSCs.

Electrical contact materials are increasingly widely used, but the existing electric contact lubricants still have lots of room for improvement, such as anti-wear performance and lubrication life. Due to the excellent electrical and lubrication properties, graphene shows great potential in lubricating the sliding electrical contact interface, but there is a lack of relevant research. Some researchers have studied the lubrication performance of graphene between the gold-coated/TiN-coated friction pair at an ultra-low current. However, the lubrication performance of graphene on more widely used electrical contact materials such as copper and its alloys under larger and more commonly used current or voltage conditions has not been reported. In this paper, we study the lubrication performance of graphene in the copper and its alloys sliding electrical contact interface under usual parameters, which is explored through four aspects: different substrates—copper and brass, different test methods—constant voltage and constant current, different normal loads and durability test. The experiments demonstrate that graphene can significantly reduce the friction and wear on brass and copper under the above test methods and parameters, with low contact resistance at the same time. Our work is expected to provide a new lubricant for electrical contact materials and contribute to enriching the tribological theory of graphene.

Faculty hiring and retention determine the composition of the US academic workforce and directly shape educational outcomes1, careers2, the development and spread of ideas3and research priorities4,5. However, hiring and retention are dynamic, reflecting societal and academic priorities, generational turnover and efforts to diversify the professoriate along gender6–8, racial9and socioeconomic10lines. A comprehensive study of the structure and dynamics of the US professoriate would elucidate the effects of these efforts and the processes that shape scholarship more broadly. Here we analyse the academic employment and doctoral education of tenure-track faculty at all PhD-granting US universities over the decade 2011–2020, quantifying stark inequalities in faculty production, prestige, retention and gender. Our analyses show universal inequalities in which a small minority of universities supply a large majority of faculty across fields, exacerbated by patterns of attrition and reflecting steep hierarchies of prestige. We identify markedly higher attrition rates among faculty trained outside the United States or employed by their doctoral university. Our results indicate that gains in women’s representation over this decade result from demographic turnover and earlier changes made to hiring, and are unlikely to lead to long-term gender parity in most fields. These analyses quantify the dynamics of US faculty hiring and retention, and will support efforts to improve the organization, composition and scholarship of the US academic workforce.

The tin oxide (SnO2) electron transport layer (ETL) plays a crucial role in perovskite solar cells (PSCs). However, the heterogeneous dispersion of commercial SnO2colloidal precursors is far from optimized, resulting in dissatisfied device performance with SnO2ETL. Herein, a multifunctional modification material, ammonium citrate (TAC), is used to modify the SnO2ETL, bringing four benefits: (1) due to the electrostatic interaction between TAC molecules and SnO2colloidal particles, more uniformly dispersed colloidal particles are obtained; (2) the TAC molecules distributed on the surface of SnO2provide nucleation sites for the perovskite film growth, promoting the vertical growth of the perovskite crystal; (3) TAC-doped SnO2shows higher electron conductivity and better film quality than pristine SnO2while offering better energy-level alignment with the perovskite layer; and (4) TAC has functional groups of C═O and N–H containing lone pair electrons, which can passivate the defects on the surface of SnO2and perovskite films through chemical bonding and inhibit the device hysteresis. In the end, the device based on TAC-doped ETL achieved an increased power conversion efficiency (PCE) of 21.58 from 19.75% of the reference without such treatment. Meanwhile, the PSCs using the TAC-doped SnO2as the ETL maintained 88% of their initial PCE after being stored for about 1000 h under dark conditions and controlled RH of 10–25%.

[Display omitted] • The roles of rarely explored lamellar orientations (0° and 45°) in regulating size-dependent plasticity were examined. • Smaller-is-stronger was observed in the 0° pillars due to the transition from pillar kinking to shear banding. • There exists a weakest diameter in the 45° pillars, at which constraint effect and dislocation starvation are ineffective. • Strain hardening rate decreased with decreasing pillar diameter due to the diminishing dislocation accumulation. The effect of lamellar orientation on the deformation behavior of eutectic high entropy alloy at the micrometer scale, and the roles of two rarely explored laminate orientations (i.e., the lamellar orientation at ∼ 0° and 45° angles with the loading direction) in regulating size-dependent plasticity were investigated using in-situ micropillar compression tests. The alloy, CoCrFeNiTa 0.395 , consists of alternating layers of Laves and FCC phases. It was found that the yield stress of the 0° pillars scaled inversely with the pillar diameters, in which the underlying deformation mode was observed to transform from pillar kinking or buckling to shear banding as the diameter decreased. In the case of the 45° pillars with diameters ranging from 0.4 to 3 μm, there exists a 'weakest' diameter of ∼ 1 μm, at which both constraint effect and dislocation starvation are ineffective. Irrespective of the lamellar orientations, the strain hardening rate decreased with decreasing pillar diameter due to the diminishing dislocation accumulation that originated from the softening nature of large shear bands in the 0° pillars, and the enhanced probability of dislocation annihilation at the increased free surfaces in the 45° pillars. The findings expand and deepen the understanding of the mechanical size effect in small-scale crystalline materials and, in so doing, provide a critical dimension for the development of high-performing materials used for nano- or microelectromechanical systems. [ABSTRACT FROM AUTHOR]

SiBCN and BN/SiBCN light-leakage-proof coatings were prepared on silica optical fibers for sensing applications at high temperatures. Scanning electron microscopy was used to characterize the surface morphology and microstructure of the coated fiber. Mechanical and optical properties of the coated fiber were characterized by Raman, optical and tensile tests. Compared with the original fiber, the tensile strength of SiBCN and BN/SiBCN coated fiber show an increase of about 60% and 90% at room temperature, respectively. In addition, the tensile strength of BN/SiBCN coated silica optical fiber was increased by about 42% at 700 °C. It has been found that the improvement of the strength of BN/SiBCN coated silica optical fiber is related to the healing of defects and residual compressive stress in fibers. From the light transmittance performance of the coated fiber, it was found that BN/SiBCN double coating could be an ideal total reflection solution to protect silica optical fiber from light leakage during high temperature sensing operation.

Multisite ligand engineering on the performance of functional layers, interfaces and devices.

We propose and investigate a novel stable two-dimensional (2D) AlO2with anomalous stoichiometric ratios based on first-principles calculation. 2D AlO2has metallic properties. It possesses the rare in-plane and out-of-plane negative Poisson's ratio (NPR) phenomenon, originating from its special sawtooth-like structure. The absolute value of the NPR decreases as the number of layers increases. The adsorption of volatile organic compounds (VOCs) including CH2O, C2H3Cl and C6H6by AlO2exhibit small adsorption distance, large adsorption energy, large charge transfer and significant density of states (DOS) changes, indicating the presence of strong interactions. The desorption time of each gas molecule on the AlO2surface is also evaluated, and the results further suggest that the desorption of VOCs can be controlled by changing the temperature to achieve the recycling of AlO2. These interesting properties make 2D AlO2a promising material for electronic, mechanical and sensing applications for VOCs.

Adverse health effects associated with exposures to perfluoroalkyl and polyfluoroalkyl substances (PFAS) are a concern for public health and are driven by their elimination half-lives and accumulation in specific tissues. However, data on PFAS binding in human tissues are limited. Accumulation of PFAS in human tissues has been linked to interactions with specific proteins and lipids in target organs. Additional data on PFAS binding and unbound fractions (funbound) in whole human tissues are urgently needed. Here, we address this gap by using rapid equilibrium dialysis to measure the binding and funboundof 16 PFAS with 3 to 13 perfluorinated carbon atoms (ηpfc= 3–13) and several functional headgroups in human liver, lung, kidney, heart, and brain tissue. We compare results to mouse (C57BL/6 and CD-1) and rat tissues. Results show that funbounddecreases with increasing fluorinated carbon chain length and hydrophobicity. Among human tissues, PFAS binding was generally greatest in brain > liver ≈ kidneys ≈ heart > lungs. A correlation analysis among human and rodent tissues identified rat liver as a suitable surrogate for predicting funboundfor PFAS in human tissues (R2≥ 0.98). The funbounddata resulting from this work and the rat liver prediction method offer input parameters and tools for toxicokinetic models for legacy and emerging PFAS.

Suppressing Sn2+oxidation and rationally controlling the crystallization process of tin–lead perovskite (Sn–Pb PVK) films by suitable bonding methods have emerged as key approaches to achieving efficient and stable Sn–Pb perovskite solar cells (PSCs). Herein, the chelating coordination is performed at the top and bottom interfaces of Sn–Pb PVK films. The chelation strength is stronger toward Sn2+than Pb2+by introducing oligomeric proanthocyanidins (OPC) at the bottom interface. This difference in chelation strength resulted in a spontaneous gradient distribution of Sn/Pb within the perovskite layer during crystallization, particularly enhancing the enrichment of Sn2+at the bottom interface and facilitating the extraction and separation of photogenerated charge carriers in PSCs. Simultaneously, this top-down distribution of gradually increasing Sn content slowed down the crystallization rate of Sn–Pb PVK films, forming higher-quality films. On the top interface of the PVK, trifluoroacetamidine (TFA) was used to inhibit the generation of iodine vacancies (VI) through chelating with surface-uncoordinated Pb2+/Sn2+, further passivating defects while suppressing the oxidation of Sn2+. Ultimately, the PSCs with simultaneous chelation at both top and bottom interfaces achieved a power conversion efficiency (PCE) of 23.31% and an open-circuit voltage (VOC) exceeding 0.90 V. The stability of unencapsulated target devices in different environments also improved.

A solar cell, capable of directly converting solar energy into electricity, bears a Shockley-Queisser limit of about 31% based on a single pn junction. In general, less than 50% of the solar irradiation spectrum (mostly in the ultraviolet and visible regions) can be utilized for the conversion. As such, the theoretical utilization rate is less than 15% in a single device, with most of the extra energy being lost as heat. It is thus appealing to enhance the energy utilization with devices that could collect the heat loss. In this study, we design and demonstrate a solar tube to realize photo-electric and photo-thermal conversions simultaneously. The key point is the use of titanium tube: (1) it has a small plasma frequency to enable wide absorption for thermal conversion; (2) it accommodates TiO2nanotube arrays to solve the cracking problem under tensile stress. A sandwiched membrane of high transparency and conductivity is developed for hole transport and collection. Eventually, a total energy efficiency of about 25.2% is obtained. Such a solar tube is anticipated to highly boost the utilization rate of solar energy with judiciously designed structure.

Although much of the initial progress in perovskite solar cells has been made by the archetypal CH3NH3PbI3, incorporation of an additional cation such as formamidinium, cesium, and mixed halides have shown promising results in both stability and device performance. However, the role of the additional cations as well as the mixed halides is yet to be fully understood. In this work, we investigate the role of different additives including group I alkali metal cations (K, Rb, Cs and NH4) and halide anions (Br and I) on double-cation perovskites, i.e., [(MAPbBr3)0.15(FAPbI3)0.85]. A notably longer charge carrier lifetime is achieved for perovskite films with additives and may be attributed to defect passivation. Selection rules are put forward based on the effect of the ionic size of an additive on phase stabilization and defect passivation. Addition of complementary size cation with respect to cation size of the parent perovskite, mainly helps stabilizing the perovskite phase by tuning tolerance factor, while addition of the similar size cation/anion, acts as defect passivator. The performance improvement of devices fabricated using NH4I as additive well supports this hypothesis, and offers yet another pathway toward harnessing the multitude of perovskite compositions to achieve high performing solar cells and perhaps other optoelectronic devices.

Large-scale and mass production of uniform nanostructured materials has been a growing challenge. Anodic titania nanotubes have been widely employed in various applications, which are usually demonstrated with limited size and planar geometry. In this study, a coaxial electrochemical anodization approach is explored and reported. With this method, uniform titania nanotube arrays are produced at the inner surface of titanium tubular electrodes of 1000 mm in length and 10 mm in diameter, in good contrast to the nonuniform nanotubes attained with a conventional anodizing scheme. Such an approach is cost-effective and energy-efficient. It is also capable of processing other valve metals possible for anodization and even longer tubular substrates. The wetting property of the resulting nanotube arrays is further tailored, with a maximum contact angle of 166° for water and 163° for glycerol, exhibiting a superhydrophobic feature. An equation is derived to compute the intrinsic contact angle of a spherical droplet on an asymmetric tubular substrate, based on measurable apparent contact angle, droplet radius, and tube radius. Such a superhydrophobic tube with a sliding angle of <3° is promising to be applied in drag reduction, condensation heat transfer, microfluidics, etc.

The advent of triboelectric nanogenerator (TENG) preludes the high entropy energy harvesting and is gradually applied to droplet energy harvesting. However, the mainstream research concentrates on exploring the solid-liquid contact electrification (CE) and electrostatic induction (EI) processes, ignoring the possibility of charge extraction from water. As a result, the droplet-based nanogenerator (DNG) is limited to small alternating-current (AC) output, which also asks for complex power management. This study reveals that the displacement current is not the sole driving force during the power generation of DNG, and the contribution of the conducting current is equally important. Here, the existence of conducting charge is confirmed by a top-electrode-only DNG, and the charge transfer processes in traditional DNGs are re-examined. Finally, a three-electrode total current DNG is introduced to enhance the coupling of displacement current and conducting current. The charge extraction efficiency is then improved by more than one order of magnitude (charge extraction from single droplet is increased from 1 to 27.3 nC) and retains the direct-current (DC) and high voltage (up to 2315V) output characteristics.

Soft magnetic material FeCoV is sensitive to magnetic field and its cost is lower than giant magnetostriction materials (Terfenol-D et al.). In the present investigation Pb (Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) with different thickness and FeCoV laminate with 0.8mm thickness were assembled into layer structure to study the effect of the PMN-PT volume fraction on the magnetoelectric coefficient of PMN-PT/FeCoV laminate composites. The ME coefficients and voltages have been characterized in the longitudinally magnetized and transversely polarized mode. The measurement was conducted under a static magnetic field superimposed with an alternating magnetic field. The influences of the static and the alternating field strength were discussed. The peak ME coefficient was obtained at 430 Oe. With the volume fraction of PMN-PT increased, the ME coefficient decreased within the experiment fraction. It can be explained by the module of M.I.Bichurin. A linear relationship was observed between the magnetoelectric voltage and the alternating field strength under a static field of 400 Oe. The ME voltage decreased when the PMN-PT volume fraction increased in the experiment fraction.

A solid-state, flexible solar cell based on titanium (Ti) foil/TiO2nanotubes (TNTs) with organic–inorganic halide perovskite absorber and transparent carbon nanotube electrode is demonstrated. TNT arrays together with an inherent blocking layer were simultaneously formed on Ti foil during one-step anodization. TNT arrays serve as deposition scaffold and electron conductor for perovskite absorber. Transparent conductive carbon nanotube network is laminated on top of perovskite and serves as hole collector as well as transparent electrode for light illumination. Under AM 1.5, 100mWcm−2illumination, power conversion efficiency of 8.31% has been achieved, which is among the highest for TiO2nanotube based flexible solar cells. Interestingly, up to 100 mechanical bending cycles show little deterioration to the device performance, demonstrating good flexibility of the Ti foil based perovskite solar cells. The Ti foil based solid-state, flexible perovskite solar cells have great potential for applications in building photovoltaics and wearable electronic devices.

Liquid-solid based triboelectric nanogenerator (L-S TENG) has aroused great attention in blue energy harvesting. Although these classical L-S TENG can achieve good performance by using the gradually changed displacement current, the further improvement of instantaneous power is limited. People can improve the output with external management circuits and transistor-like architecture, but the complex structure and fabrication process of devices make the practicality of TENG very difficult. Here, by developing the structure of charge collector needle to introduce conduction current into the traditional architecture of TENG, we designed a new water tube TENG (DcCc-TENG) with high instantaneous power. By establishing a detailed physical process model, we revealed that the physical nature of DcCc-TENG with high instantaneous power output is based on the synergistic enhancement mechanism of displacement and conduction currents. We also used the different device structures to further clarify the contribution of these two currents. Finally, a single device shows high instantaneous volumetric power density of 16.6 W/m3, which is capable to power more than 120 LEDs. A ship attitude sensor based on DcCc-TENG further proves its potential application in sensing.

Although the phenomenon that optical reflectivity of hard group IVB transition metal nitrides depends on stoichiometry has been reported, the microscopic origin of this behavior has not been well explored yet. Here we find that optical reflectivity of rocksalt hafnium nitride films (δ-HfNx) can be effectively tuned by stoichiometry x, and the underlying mechanism can be well elucidated by Drude–Lorentz fitting and first-principles calculations. It is shown that the observed tunability of optical reflectivity arises from a transition from N vacancies (VN) to Hf vacancies (VHf) in the films because this evolution from VNto VHfhas important roles in changing electronic properties of the films in the following three aspects: (i) density of free electrons, wherein VNand VHfact as donor-like and acceptor-like defects, respectively; (ii) mean free path of free electrons, in which VNand VHfare the main electron scattering sites in sub- and overstoichiometric films, respectively; (iii) interband transition absorption of bound electrons, wherein three previously unreported absorption bands originating from VNand VHfare found to occur at ∼0.81, 2.27, and 3.75 eV. These point-defect-induced variations significantly affect the dielectric function of δ-HfNxfilms and thus drive the tailored evolution in reflectivity properties with x.

An optimized two-step anodization is developed to fabricate ultralong, small-diameter TiO2nanotubes, that is, with tube length of up to 31 μm and pore diameter of about 35 nm in this work. This overcomes the length limitation of small diameter tubes that usually presents in conventional one-step anodization. The small tubes with lengths of 23 μm yield a conversion efficiency of 5.02% in dye-sensitized solar cells under nonoptimized conditions.

We report the intrinsic room-temperature ferromagnetism in undoped ZnO nanoparticles with different sizes synthesized by a wet chemical method at different temperatures. Electron paramagnetic resonance, X-ray photoelectron spectroscopy, and photoluminescence measurements demonstrate clearly the singly charged oxygen vacancies are the main defects, and the relative occupancy of that decreases with increasing sizes and annealing temperatures. Importantly, a direct correlation between the ferromagnetism and the relative concentration of the singly charged oxygen vacancies is established, which suggests that the singly charged oxygen vacancies play a crucial role in modulating ferromagnetic behaviors. Moreover, the size-dependent ferromagnetism can be manipulated conveniently by changing of the surface–volume ratio, which is in favor of future electronic and spintronic application.

A series of the magnesium apatite coatings according to (Ca10-xMgx)(PO4)6(OH)2, where x = 0 to 2, was synthesized through a sol-gel dip-coating method. The roughness of the magnesium coatings increased as more magnesium incorporated into the coatings. The mechanical properties of the coatings were analyzed with Nanoindentor. The incorporation of magnesium decreased the hardness and the Young’s modulus of the coating. The X-ray Photoelectron Spectroscopy (XPS) analysis revealed that only part of magnesium was incorporated into the apatite structure while the rest existed in the form of MgO in the coating.

Synergy at work!A dual‐phase photocatalyst comprising anatase and protonated titanate, synthesized by a low‐temperature one‐pot process, synergistically adsorbs and degrades methylene blue dye under visible light. The two phases (see figure) work harmoniously to give accelerated breakdown of the organic dye.

The microstructures of the as-sputtered amorphous silicon-rich oxide (SiOx) films were investigated by using a combination of X-ray photoelectron spectroscopy (XPS) and Raman microscopy. XPS analysis reveals that the as-sputtered amorphous SiOxfilms are chemically inhomogeneous. Raman spectra and valence band XPS spectra suggest the formation of amorphous Si nanoclusters in the as-sputtered amorphous SiOxfilms. The size of these nanoclusters depends on the Si concentration in the films. The formation of amorphous Si nanoclusters was attributed to the high kinetic energy and surface migration of the sputtered Si atoms. It is found that the as-sputtered amorphous SiOxfilms have a complex structure consisting nanoscale cluster of amorphous Si core with suboxides shell embedded in the amorphous SiO2matrix.

In this paper we present the microstructural study behind the growth of carbon nanotubes (CNTs) on the multimetal buffer layers due to its importance in microelectronics and microelectromechanical systems applications. Two different buffer layers, i.e., aluminum (Al) and titanium nitride (TiN), were deposited on the conductive layers of tantalum/copper/tantalum. A thick iron film was used as a catalyst layer to grow the CNTs. The fundamental mechanism behind the formation of catalyst nanoparticles on these two buffer layers, i.e., Al and TiN, was studied and analyzed by various characterization tools, such as atomic force microscopy, X-ray photoelectron spectroscopy, and scanning electron microscope. The formation of aluminum oxide nanoparticles during the CNT growth process was observed in the case of aluminum buffer layer. From the experimental results, it was concluded that TiN can be used as a stable buffer layer on the conductive metal lines. The CNTs growth on both buffer layers was found to be in random directions, which is due to the formation of bigger and less dense catalyst nanoparticles in comparison with the CNTs grown on the conventional buffer layer of thermally grown silicon dioxide on the silicon substrate, on which vertically aligned CNTs are grown.

Solid carbon nanofibers (CNFs) made from ethanol flames were used to prepare supercapacitors. Their microstructure, crystallinity, porosity, chemical properties, and electrochemical activity were compared with the multiwalled carbon nanotubes (MWCNTs) synthesized by chemical vapor deposition. The produced CNFs have a unique microstructure with a solid core and porous surface. The specific surface area of CNFs was comparable to that of MWCNTs because of their larger amount of micropores on the surface. The synthesis environment also resulted in abundant functional groups absorbed on the surface of the CNFs. Electrochemical characterization shows that CNFs have much larger capacitance than that of MWCNTs. The capacitance of CNFs consists of both double-layer capacitance contributed by micropores and pseudo-capacitance produced from redox reactions of the absorbed oxygen functional groups. In comparison to the reported MWCNTs-based supercapacitors, the CNF demonstrates more promising potential in energy storage applications because of its larger electrochemical capacitance.

Carbon Nanotubes (CNT) were grown from amorphous carbon film when the top catalyst layer can agglomerate into nanoparticles during rapid thermal processing. The CNT grown with Co are longer and exhibit alignment at the perimeter of the substrate, while those grown with Au are straighter and denser. One large catalyst particle can support multiple CNT growth, and the effect is more pronounced with Au nanoparticles. Introduction of ethanol vapour during the thermal process increases the yield of the CNT grown with both catalysts.

For dental/orthopedic implants to achieve better bone apposition and bone-implant bonding, various approaches to improve titanium surfaces have been developed. Recently, a fluoridated hydroxyapatite (FHA) coating on titanium (Ti) implants was made by sol–gel method and shown to be a possible applicative bone implant. The purpose of the current study was to evaluate biological responses and biomechanical bonding strength of FHA coated Ti implants as compared with that of the conventional Ti alloys and hydroxyapatite (HA) coated Ti implants. In vitro assays were made using human osteoblast-like cell (MG63) culture on different implants with cell attachment, morphology and differentiation evaluations. The implant plates were also implanted into the proximal metaphysis of New Zealand White rabbit tibiae. After 8 and 16 weeks implantation, mechanical and histological assessments were performed to evaluate biomechanical and biological behavior in vivo. The results showed that the cell adhesion and cell growth rate on the FHA and HA surface was higher than that on cp Ti surface (p<0.01), and insignificant difference was observed between two coated groups. Mechanical test demonstrated that the FHA implants had a higher interface shear strength than the both controls at 8 and 16 wks, with no significant difference with HA-Ti. Histologically, the coated implants revealed a significantly greater percentage of bone-implant contact when compared with the uncoated implants. Results demonstrated that the new FHA surface improved cell adhesion and proliferation. The coating exhibited a bioactive mechanical and histological behavior at bone-implant interface, suggesting that a useful approach by combined coating processes could optimize implant surfaces for bone deposition and early implant fixation.

The objective of this study was to evaluate the interface shear strength and the responses of osteoblast-like cells to titanium implants with a sandblasted and acid-etched surface modified by alkali and heat treatments (SLA-AH). The implants with machined and SLA surface served as controls. Each type of implant was characterized by scanning electron microscopy (SEM) and energy-dispersive x-ray (EDX) analysis. In vitro assays were made using human osteoblast-like cell culture on different surfaces. The rectangle plates were also transcortically implanted into the proximal metaphysis of New Zealand White rabbit tibiae. After 4, 8 and 12 weeks implantation, mechanical and histological assessments were performed to evaluate biomechanical and biological behavior in vivo. By SEM examination, SLA surface combined with AH treatments revealed a macro-rough surface with finely microporous structure. The in vitro assays showed that the SLA-AH surfaces exhibited more extensive cell deposition and improved cell proliferation as compared with controls. Pull-out test demonstrated that the SLA-AH treated implants had a higher mechanical strength than the controls at all interval time after implantation. Histologically, the test implants revealed a significantly greater percentage of bone-implant contact when compared with controls. The results of this study suggest that a useful approach by combined processes could optimize implant surfaces for bone deposition and produce distinct biological surface features.

Fluoridated hydroxyapatite (FHA) has been successfully synthesized via sol-gel method with HPF6as the fluorine containing reagent. The chemical reactions induced by HPF6addition and the formation process of fluoridated hydroxyapatite (FHA) are investigated. The hydrolysis and alcoholysis of HPF6release F ion into the solution which, in turn, reacts with Ca ion to form nanocrystalline CaF2(nc-CaF2). These nc-CaF2improves the gelation ability of the system through formation of F‒H hydrogen bonding between F in nc-CaF2and H in P precursors. Increasing HPF6leads to more nc-CaF2thus less Ca(NO3)2in the dried gel, or the presence of nc-CaF2in the gel suppresses the formation of Ca(NO3)2. At elevated firing temperatures, the P containing groups react with each other to form condensed phosphate. These condensed calcium phosphate, nc-CaF2/Ca(NO3)2, reacts with the rest of the amorphous phase to form FHA phase at above 400°C.Fluoridated hydroxyapatite (FHA) has been successfully synthesized via sol-gel method with HPF6as the fluorine containing reagent. The chemical reactions induced by HPF6addition and the formation process of fluoridated hydroxyapatite (FHA) are investigated. The hydrolysis and alcoholysis of HPF6release F ion into the solution which, in turn, reacts with Ca ion to form nanocrystalline CaF2(nc-CaF2). These nc-CaF2improves the gelation ability of the system through formation of F‒H hydrogen bonding between F in nc-CaF2and H in P precursors. Increasing HPF6leads to more nc-CaF2thus less Ca(NO3)2in the dried gel, or the presence of nc-CaF2in the gel suppresses the formation of Ca(NO3)2. At elevated firing temperatures, the P containing groups react with each other to form condensed phosphate. These condensed calcium phosphate, nc-CaF2/Ca(NO3)2, reacts with the rest of the amorphous phase to form FHA phase at above 400°C.

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Nanocrystalline TiN (or nc-TiN) has been imbedded in amorphous silicon nitride (a-SiNx)matrix to form a nanocomposite thin film (nc-TiN/a-SiNx) via magnetron sputtering deposition on silicon wafer. Two important effects of the Si3N4 sputtering target power on the formation of nc-TiN/a-SiNx have been studied: (1) Aside from forming a-SiNx in the matrix, Si atoms also imbed into TiN to form (Ti,Si)N solid solution crystallites. At low target power, the solid solution is substitutional. With increase of power, the amount of silicon “dissolved” in the TiN crystallite increases, and in the meantime, the interstitial components increase which is manifested in the increase in the TiN lattice parameter. (2) The crystallites have a preferred orientation varying with the deposition target power. As conveniently described by the coefficient of texture, the degree of preferred orientation along [111] direction decreases and finally tails off with increase of power. At the same time, the crystallites orient along [200] and [220] direction and eventually [220] direction dominants.

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Different compaction processes were employed in studying the effect of green state on the sintering of TiC-TiN-Ni-Mo2C and Ti(C0.3N0.)-Ni-Mo2C cermets. Specimens were uniaxially pressed and some being subsequently compacted by cold isostatic pressing. Liquid and solid phase sintering was carried out in nitrogen atmosphere. Green state porosity, pore size distributions, as sintered morphologies, micro-hardness and microstructural development were characterized. Mercury porosimetry measurements indicate that with increasing compacting pressure, large pores are eliminated and the pore size distribution curves shift towards smaller pores. Higher compaction load also leads to decrease in average pore size and a wider pore size distribution. It was found that the Ti(CN)-based cermets are superior than the (TiC-TiN)-based cermet. Cermets with carbowax additives are better sintered than those without the wax. The two-stage consolidation (diepressing + CIP) results in better sintering properties than die-pressing alone.

Chronic lymphocytic leukemia (CLL) cells of nearly all patients (pts) express ROR1 (Receptor tyrosine kinase-like Orphan Receptor 1), an orphan-receptor tyrosine-kinase-like protein that is normally expressed during embryogenesis, but not by normal post-partum tissues. ROR1 is a receptor for Wnt5a, which can induce non-canonical Wnt signaling to enhance CLL-cell survival and/or proliferation. We have developed antibodies that bind to epitopes that span the extracellular portion of human ROR1, and selected one mAb that had the most potent activity in inhibiting such signaling. We fully humanized this antibody to generate UC-961 (cirmtuzumab). GLP-compliant studies demonstrated that this antibody does not cross-react with normal post-partum tissues. Preclinical pharmacology/toxicology studies in Sprague-Dawley rats showed no evidence of toxicity for cirmtuzumab at doses up to 400 mg/kg by IV administration with an apparent half-life exceeding 7 days. Studies in cynomolgus monkeys again showed no apparent toxicity with an antibody half-life of approximately 14 days. Based on these IND-enabling studies, we have initiated a first-in-human phase 1 dose escalation study to determine the safety and tolerability of cirmtuzumab in the treatment of pts with relapsed or refractory CLL. Here, we report results of planned interim safety analysis of pts in the initial phase 1 cohorts.

A nitrogen doped dual‐phase photocatalyst consisting of interdispersed protonated titanate and anatase nanocrystallites with the empirical formula H2Ti3O7·xH2O is synthesized from Ti(OiPr)4in a mixture of triethylamine, acetylacetone, ethanol, and water in a molar ratio of 4:1:20:3 (autoclave, 160 °C, 3 h).

The polarization behavior of (La0.8Sr0.2)0.9MnO3(LSM) electrodes in contact with different chromia-forming alloys including a Ni–Cr-based superalloy (R600), and ferritic stainless steels (RA446 and Crofer22 APU) was studied under solid oxide fuel cell (SOFC) operating conditions. The magnitude of the polarization potential increase, ΔE, depended on the composition and microstructure of the oxide scale formed on the alloy surface. Crofer22 APU alloy showed the lowest ΔEchange as a function of the cathodic polarization time among the chromia-forming alloys studied. This is most likely due to the formation of the dense and void-free oxide scale and the (Cr,Mn)3O4spinel phase formed in the top layer of the oxide scale decreases the chromium volatility of the scale. The result demonstrates the feasibility of the electrochemical polarization method in the qualitative diagnosis of the Cr volatility of chromia-forming alloys as interconnect for SOFC applications.

The effect of modifying Cu/dielectric cap interface on electromigration (EM) in dual-damascene interconnect structures is presented. The Cu surface was treated with reducing (NH3, H2) and reactive (SiH4)gases immediately after chemical mechanical polishing, but prior to SiNxdielectric cap deposition. Thus, compositions change at the interface capped by different layers including copper silicide and nitride. The Cu∕SiNxinterfacial reactions upon different treatments were detailed by X-ray photoelectron spectroscopy analysis, which correlated to the EM lifetimes very well. NH3treated samples showed similar failure times as control samples with no surface treatment. Significant improvement was observed for hydrogen plasma and silane treatment structures. It is found that, upon different surface treatments, formation of Cu silicide has a higher impact on EM lifetime improvement than formation of Cu nitride.

The interaction between a chromia-forming alloy interconnect and (La,Sr)MnO3∕Y2O3–ZrO2(LSM/YSZ) and Gd-doped CeO2(GDC)-impregnated LSM electrodes is investigated under solid oxide fuel cell operating conditions. LSM/YSZ and GDC-impregnated LSM composite electrodes show much higher electrochemical activity and performance stability in comparison to that of pure LSM. In contrast to that on the pure LSM electrode, there is no preferential deposition of Cr species at the electrode and electrolyte interface region for the reaction on the LSM/YSZ composite electrode with high YSZ content (≥30wt%)and a 1.6mgcm−2GDC-impregnated LSM composite electrode. The amount of Cr deposits is also much smaller in comparison to that on the pure LSM electrode. The reason for the significantly reduced Cr deposition in the LSM composite cathodes is most likely due to the decrease of Mn2+ions generated under cathodic polarization, which leads to the significant reduction in the nucleation and grain growth reaction for the Cr deposition. The results demonstrate that LSM composite and GDC-impregnated LSM electrodes have high tolerance toward Cr species.