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In pursuing high precision and high-quality surface of silicon carbide (SiC) substrates for electronic applications, however, the processing efficiency on Si-face has long been a difficult challenge compared to that of the C-face. Conventional polishing slurries are aqueous-based due to its unparalleled compatibility with most of chemical reagents, and have been widely studied and well understood. The chemical reactivity of all added accelerating agents in aqueous polishing systems is constrained by the prevalent presence of water as a solvent. On the other hand, non-aqueous polishing systems have not been well explored. In this report, reactive non-aqueous organic systems containing polar hydroxyl groups are evaluated as a high efficiency processing vehicle for Si-face polishing of SiC on fixed abrasive pads (FAPs). The surface quality of SiC is surprisingly improved while the polishing efficiency is accelerated on a diamond FAP in presence of methanol compared to those using water, and are further improved when organic acids are introduced to the reactive non-aqueous fluids. Contact angle measurement and X-ray photoelectron spectroscopy (XPS) analysis on the polished SiC surface are completed to assist us to shed light on the removal behavior and to explore and elucidate the removal mechanism of non-aqueous system fluids on FAPs. The initial positive results from this reactive non-aqueous polishing system serves our community as a promising approach for the ultra-precision polishing on other hard-to-process semiconductor and ceramic materials.

The fixed agglomerated diamond abrasive pad had been used to planarize ultra-hard and brittle materials such as sapphire and SiC. However, the processing stability and surface integrity of sapphire remain to be improved. A silica-assisted fixed agglomerated diamond abrasive polishing (SA-FADAP) process was developed to solve the above mentioned problems. The material removal mechanism of the SA-FADAP was explored by analyzing material removal rate gradient (MRRG), surface topography of workpieces, the pad abrasion, and wear debris in the slurry wastes. The effects of silica grains on the self-conditioning processes of fixed agglomerated diamond abrasive pads were discussed. The efficient and stable SA-FADAP was mainly realized by the chemical-mechanical interaction produced by agglomerated diamond abrasives and silica polishing slurry.

Chemo-mechanical-grinding (CMG) is a fixed abrasive process by integrating chemical reaction and mechanical grinding for sapphire wafer finishing, and shows advantages in surface integrity, geometric controllability and waste disposal. However, the material removal rate (MRR) obtained by the traditional CMG wheel is not high enough to meet the requirement from the mass production of sapphire wafers. As a potential solution, a new CMG wheel with extremely high abrasive concentration has been proposed. This paper targets on developing of binder-free abrasive pellets (BAP) with 100 wt% abrasive as well as investigating the performance of BAP in sapphire wafer finishing. The results of CMG experiment reveal that the MRR and surface roughness (Ra) of sapphire wafer finished by BAP constructed CMG wheel are able to reach 1.311 μm/h and 0.993 nm respectively. The characterization by Raman microscope indicates that the finished sapphire wafer also owns excellent subsurface integrity.

The persistent incidence of high levels of multidrug-resistant (MDR) bacteria seriously endangers global public health. In response to MDR-associated infections, new antibacterial drugs and strategies are particularly needed. Screening to evaluate a potential compound to reverse antibiotic resistance is a good strategy to alleviate this crisis. In this paper, using high-throughput screening methods, we identified that oxyclozanide potentiated tetracycline antibiotics act against MDR bacterial pathogens by promoting intracellular accumulation of tetracycline in resistant bacteria. Furthermore, mechanistic studies demonstrated that oxyclozanide could directly kill bacteria by disrupting bacterial membrane and inducing the overproduction of bacterial reactive oxygen species. Oxyclozanide effectively reduced the production of virulence proteins in S. aureus and neutralized the produced α-hemolysin, thereby effectively alleviating the inflammatory response caused by bacteria. Finally, oxyclozanide significantly reversed tetracycline resistance in animal infection assays. In summary, these results demonstrated the capacity of oxyclozanide as a novel antibiotic adjuvant, antibacterial and anti-virulence multifunctional compound to circumvent MDR bacteria and improve the therapeutic effect of persistent infections caused by MDR bacteria worldwide.

Precision polishing of mono-crystalline SiC wafers on a fixed abrasive pad is investigated by double-nano-abrasives cutting at micro/nano scale in this report. Prior to this report, a single abrasive approach in molecular dynamics simulation had been employed to illustrate the material removal mechanism in SiC polishing process, which is quite different from the real situation of the fixed abrasive polishing process. Cutting depth and spacing of abrasive particles in a fixed abrasive pads were tested to gain insights on phase transformation, subsurface damage, surface quality, material removal and friction characteristics of polished SiC wafers by molecular dynamics simulation. By following the coordination number and radial distribution function, we clearly see that the number of phase transformation atoms caused by cutting and abrasion increases with the cutting depth of nano-abrasives on the surface of SiC workpiece. Simulation results also suggest that t he phase transformation of the SiC crystal phase increases with the lateral spacing of abrasive particles in pads, while does not change much with the increase of the longitudinal spacing. It is also found that the deeper the abrasive cutting depth, the deeper subsurface damage, resulting more materials’ removal from SiC workpiece. The lateral and longitudinal abrasive spacings lead to little change the depth of subsurface damage on the wafer in MD simulation for a fixed double abrasive polishing. The surface roughness is better with the larger lateral abrasive spacing, but no clear correlation with the longitudinal abrasive spacing.

Chemical mechanical polishing (CMP) is an essential processing step to realize ultra-precision machining of the fragile material Ga2O3 crystal and obtain ultra-smooth and undamaged crystal surface. The chemical auxiliary polishing mechanism of Ga2O3 in the CMP process was studied considering that the chemical action directly affects the CMP result. First, H3PO4 and NaOH were used to regulate the pH of slurry. This slurry was then applied to the CMP experiment of Ga2O3, and the corrosion test of Ga2O3 was implemented in H3PO4 and NaOH solutions. Second, the influence of the slurry with different acids or bases on the polishing result was analyzed. Finally, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to evaluate the influence of the corrosive action on the chemical structure of the crystal surface. Results showed that the slurry prepared by H3PO4 was more suitable for the CMP of Ga2O3 than that prepared by NaOH. The polishing efficiency was enhanced by approximately 20% and the surface quality was improved, with surface roughness of 0.21 nm. This study provides a reference for preparing the slurry of Ga2O3.

The inorganic coating of Al2O3 was introduced on nanoparticles to weaken their tendency of agglomeration in electroless plating bath. The influence of the coating on interaction energy and interaction forces between the coated particles was evaluated in this study. The Al2O3-coated diamond particles were prepared by the heterogeneous nucleation process. The attractive interaction and repulsive interaction between the coated particles in electroless nickel (EN) solution were calculated by the classical DLVO theory. Sedimentation tests were conducted to verify the modelling. The calculation predictions are well in agreement with the experimental results. The Al2O3 coating could reduce van der Waals attraction by enlarging the surface separation distance of diamond particles, and could increase electrical double layer repulsion by increasing the surface potentials in EN solution. Consequently, it could weaken the net attractive interaction, whose net attractive force decreased from −3.77×10−2N/m between bare particles to −1.12×10−2N/m between the coated ones, a reduction by 70%, at the separation distance of 1κ−1. The coated diamond particles in EN solution show a slower settling rate than bare ones. The Al2O3 coating contributes to the high dispersability of the coated particles under the agitation condition.

Ultra-fine diamond grains are used to prepare agglomerated diamond (AD) abrasives that are, in turn, applied to make fixed agglomerated diamond abrasive (FADA) pads. The as-prepared pads demonstrated very low removal efficiency along with a poor processing stability，which limits the applicability of ultra-fine diamond grains in fixed abrasive tools. In this reported research, mixed-size agglomerated diamond (MAD) abrasives with a combination of ultra-fine diamond grains and coarser diamond grains were employed to make FADA pads for lapping BK7 glass. Three types of FADA pads were manufactured with ultra-fine AD abrasives, coarser AD abrasives and MAD abrasives, respectively, for maximizing the process efficiency and stability of fixed abrasive pads consisting of ultra-fine diamond abrasives while improving the surface quality of the lapped glass substrates. The results showed that a FADA pad with MAD abrasives exhibited higher material removal rate (MRR) than a pad with AD abrasives of ultra-fine diamond grains only and lower surface roughness Ra and better surface microstructure than a pad with AD abrasives of coarser diamond grains. The distinct lapping feature of MAD abrasives was that the coarser diamond grains mainly accelerate the lapping efficiency while the ultra-fine diamond grains improved the surface quality of workpiece.

Molecular dynamics (MD) as a powerful simulation tool revealed the mechanistic removal behaviors of SiC substrates using a fixed abrasive polishing (FAP) with randomly distributed multi-abrasive particles in a single cycle scratching at nano-scales. This study presents features of surface morphology, subsurface damage and temperature distribution of SiC substrates in nano-abrading. It is demonstrated that the exposed height and abrasive distribution of multi abrasives in a single pad asperity (SPA) dominates the removal behaviors of SiC substrates. MD simulation reveals that the random distribution of diamond abrasives in FAP pad would worsen the processing quality. Our investigation sheds new insights into the mechanical removal mechanisms of SiC in FAP at an asperity-scale.

Signal transduction system and specialized secretory devices are crucial for bacteria to sense and adequately adapt in adverse environmental conditions. Therefore, it's crucial for microbes to detect and respond to lethal attacks when envelope is perturbed so as to minimize and fix the damage in milieu. We investigated the adaptive response of porcine extra-intestinal pathogenic Escherichia coli PCN033 to polymyxin B challenge. Treatment with polymyxin B led to rapid and robust activation of Rcs system via RcsF, as well as the accumulation of reactive oxygen species. ExPEC T6SS expression was strongly induced by RcsB in Rcs system, resulting in the reduction in the damage to constitute a survival strategy. Finally, we show that T6SS of ExPEC is involved in its pathogenicity in mouse model. Compared with the wild type strain, the deletion of T6SS genes led to a decrease in the organ colonization ability, and the RcsFS2DM3Q mutant that caused Rcs activation had a stronger colonization ability than the wild type strain. In conclusion, Rcs system orchestrates Rcs cascade to trigger antioxidant defense of T6SS, and presents a typical model in which a bacterium reschedule its transcription network via the Rcs phosphorelay pathway in response to membrane perturbations for survival and pathogenesis.

The processing efficiency and stability of ultra-hard and brittle materials plannarized by fixed abrasive pads (FAPs) are largely determined by the cutting depth and the available number of active cutting abrasives and the abrasive wear behaviors. A newly prepared agglomerated diamond (AD) abrasive embedded in FAPs has demonstrated a significant improvement on processing efficiency and stability while being used to lap hard-to-processed ceramic materials. A mathematical model was built to explain the high removal efficiency of the AD abrasives, which followed a similar trend with experimental testing results. The micro-cutting and self-sharpening capabilities of the AD abrasive, which afforded FAPs with AD abrasives to improve efficiency and stability, were manifested by our experimental examinations on the worn abrasive morphologies, the fall-out diamond chips and scratch marks left on sapphire substrates by AD abrasives.

Further to explore the effect of the agglomerated diamond (AD) abrasive wear on material removal behavior of sapphire in lapping, the pin-on-disk test with an AD abrasive was carried out. The classifications of AD abrasive wear, material removal behavior of sapphire, friction coefficient of sliding contact and removal ratio of sapphire material were thoroughly investigated. The wear behavior of the AD abrasive shows two types: attrition wear and micro-fracture. Three wear statuses of the active cutting diamond grains fixed on the AD abrasive surface, including attrition wear, worn-flat and pull-out, occur in the tests. The sapphire material is mainly removed by the AD abrasive via plastic deformation. The micro-fracture feature of the AD abrasive improves its self-sharpening ability. Therefore, the micro-cutting action of the AD abrasive on the sapphire wafer has behaved well.

Lignin accumulation is a general response to heavy metal toxicity; however, the underlying mechanism is unclear. We isolated two rice l ignin- d efective m utants (ldm1 and ldm2); both showed reduced mechanical strength and lignin accumulation. Also, the levels of the syringyl and guaiacyl units of lignin were decreased in both mutants. Both mutants were more hypersensitive to excess Cu than wild-type plants, possibly resulting from more Cu in leaf sheaths and roots of the mutants than wild-type plants. Moreover, Cu retention in the cell wall was altered in the ldm1 and ldm2 mutants. Genotypic analysis confirmed that ldm1 has a T-DNA insert in the last exon of OsCCoAMT1 and ldm2 in the second exon of OsCCoAMT20. Consistently, both mutants displayed significantly decreased CCoAOMT enzymatic activity in all tissues examined, which catalyzed the transfer of methyl groups from S-adeosyl-Lmethionin (SAM) to benzene carbon 3 position of caffeoyl-CoA or 5-hydroxyferuloyl-CoA. Furthermore, the expression of OsCCoAOMT1 and CCoAOMT20 and CCoAOMT activity were upregulated in leaf sheaths and roots under excess Cu, suggesting that lignin synthesis mediated by OsCCoAOMT1 and OsCCoAOMT20 plays an important role in the adaptation to excess Cu stress. Based on the role of lignin in the sequestration of heavy metals in the plant cell wall, we speculate that enhancement of lignin synthesis may be an adaptive strategy to alleviate the toxicity of Cu ions.

The mechanical properties of mono-crystalline SiC with vacancy defects in fixed abrasive polishing processes are not well known at the nanometric scale. In the molecular dynamic (MD) simulation, the removal mechanism of mono-crystalline SiC substrates with vacancy defects is investigated. So is the wear mechanism of diamond abrasives explored. The simulation result reveals that the increase of vacancy defects in SiC substrates leads to reduced von Mises Stress, however, to increased temperature of SiC substrates during nano-abrading process. More vacancy defects are found to lead higher removal efficiency and less subsurface damage on SiC substrates. Furthermore, the diamond abrasives are worn out through a combination of thermo-chemical wear, graphitization wear and abrasive wear in the simulation.

Fixed abrasive is taking the place of loose abrasive owing to its high efficiency and little pollution. The self-conditioning ability of fixed abrasive pads (FAPs) plays a favorable role in the lapping process. In this paper, agglomerated diamond (AD) abrasives were prepared for the sapphire lapping process. Material removal rate (MRR), material removal rate variation (MRRV) and surface topography of sapphire wafers lapped by fixed AD abrasive pad were investigated. Abrasive wear and wear debris were characterized. The material removal mechanisms of AD abrasives were discussed. Comparison of mechanical properties between AD and SD in abrasive wear process was analyzed. Influence of mechanical properties of AD abrasives on processing performance was explained. Comparing with fixed single diamond (SD) abrasive pads, the higher MRR, the lower MRRV and surface roughness of sapphire wafer were obtained in the fixed AD abrasive lapping process. Stable large protrusion height and consecutive sharp edges of AD abrasives ensure the excellent lapping performance. The protrusion height of abrasives is positive correlated with the self-conditioning ability of FAPs. The stable protrusion height of AD abrasives is attribute to two points: one is the rough surface of an AD abrasive with multiple sharp cutting edges improves the bonding strength between the abrasives and the pad matrix; the other is the detached diamond particles due to the micro-fracture phenomenon of AD abrasives accelerates the abrasion of matrix.

When hydrophobic particles are employed to prepare self-lubricating electroless composite coatings, they usually require surface modification to improve their wettability. The study focuses on the resultant change in wettability of the MoS2 particles with an inorganic coating. Al2O3-coated MoS2 particles were prepared by using a heterogeneous nucleation process. Then, particle surface morphology and structure were examined by using SEM, EDS and XRD. Contact angle measurements were conducted by using a thin layer wicking technique and a sessile drop method in order to determine the surface free energy components of the bare and the coated MoS2 particles. Our results showed the MoS2 particles were successfully coated with an Al2O3 layer, which is an amorphous structure. The decreased water contact angle indicates an enhanced hydrophilicity for the coated particles. This decrease depends more strongly on a significant decrease of a new parameter ratio, γ+/γ−, than on a slight increase in total surface free energy. The surface energy component of the bare MoS2 is very consistent with that of Talc, and that of the Al2O3-coated one is very similar to that of alumina, apart from the base component.

Escherichia coli is one of the primary causes of bacterial sepsis and meningitis in newborns. E. coli RS218, a prototype strain of neonatal meningitis E. coli (NMEC), is often used in research on the pathogenesis of NMEC. Phagocytes are crucial sentinels of immunity, and their antibacterial ability is largely determined by the capability to produce large amounts of ROS. The capacity of bacteria to endure oxidative pressure affects their colonization in the host. Here, we systematically screened the genes that plays key roles in the tolerance of the model of E. coli RS218 to peroxygen environment using a Tn5 mutant library. As a result, a gene encoding O antigen polymerase (O antigen ligase) that contains the Wzy_C superfamily domain (herein designated as Ocw) was identified in E. coli RS218. Furthermore, we constructed an isogenic deletion mutant of ocw gene and its complementary strain in E. coli. Our results revealed that ocw affects the lipopolysaccharide synthesis, ROS tolerance, and survival of E. coli in the host environment. The discovery of ocw provides important clues for better understanding the function of O-antigen.

The ability for self-conditioning is the most important characteristic of hydrophilic Fixed Abrasive (FA) pads using in lapping. The failure mode of diamond abrasives embedded in a FA pad greatly impacts its self-conditioning process. In this investigation, three types of FA pads were prepared. One was embedded with W50 single crystal diamond (SCD) abrasives, one was embedded with W10 SCD abrasives, and the other was embedded with agglomerated diamond (AD) abrasives. The lapping performance was tested on fused quartz workpieces. The pad wear mechanisms and the wear debris of the three pads was evaluated using Scanning Electron Microscopy (SEM). The FA pad embedded with AD exhibited a higher material removal rate and a lower arithmetic average surface roughness (Ra) of the lapped quartz than those embedded with SCD. Pad loading and flattening of the of abrasive grit are the main factors causing the failure of FA pad with SCD. Compared with FA pads with SCD, the rough surfaces of AD grains improves the holding force of pad matrix to them, which in turn leads to a more stable cutting depth of abrasive grain. Size analysis of the debris suggests that AD grains are inclined to micro-fracture rather than to wear flat or pull out. The micro-fracture phenomenon of AD in FA lapping process improves the material removal rate and lowers the average surface roughness of lapped work-pieces. The adoption of AD grains was concluded to be important in improving the self-conditioning performance of FA pads.

The microwave absorption properties of the nanocrystalline NiZn ferrite (Zn 0.5 Ni 0.5 Fe 2 O 4 ) and iron (α-Fe) microfibers with single-layer and double-layer structures were investigated in the frequency range of 2–18 GHz. The double-layer absorbers have much better microwave absorption properties than the single-layer absorbers, and the microwave absorption properties of the double-layer structure are influenced by the coupling interactions between the absorbing layer and matching layer. With the absorbing layer thickness 0.7 mm of α-Fe microfibers–wax composite and the matching layer thickness 1.5 mm of Zn 0.5 Ni 0.5 Fe 2 O 4 microfibers–wax composite, the minimum reflection loss ( RL ) reaches about −71 dB at 16.2 GHz and the absorption band width is about 9.2 GHz ranging from 8.8 to 18 GHz with the RL value exceeding −10 dB. While, when the absorbing layer is the Zn 0.5 Ni 0.5 Fe 2 O 4 microfibers–wax composite with thickness 1.8 mm and the matching layer is the α-Fe microfibers–wax composite with thickness 0.2 mm, the RL value achieves the minimum about −73 dB at 13.8 GHz and the absorption band width is about 10.2 GHz ranging from 7.8 to 18 GHz with the RL value exceeding −10 dB, which covers the whole X -band (8.2–12.4 GHz) and K u -band (12.4–18 GHz).

CoFe 2− x Sm x O 4 ( x = 0–0.2) nanofibers with diameters about 100–300 nm have been prepared using the organic gel-thermal decomposition method. The composition, structure and magnetic properties of the CoFe 2− x Sm x O 4 nanofibers were investigated by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, inductive coupling plasma mass analyzer and vibrating sample magnetometer. The CoFe 2− x Sm x O 4 ( x = 0–0.2) nanofibers obtained at 500–700 °C are of a single spinel structure. But, at 800 °C with a relatively high Sm content of 0.15–0.2 the spinel CoFe 2− x Sm x O 4 ferrite is unstable and the second phase of perovskite SmFeO 3 occurs. The crystalline grain sizes of the CoFe 2− x Sm x O 4 nanofibers decrease with Sm contents, while increase with the calcination temperature. This grain reduction effect of the Sm 3+ ions doping is largely owing to the lattice strain and stress induced by the substitution of Fe 3+ ions with larger Sm 3+ ions in the ferrite. The saturation magnetization and coercivity increase with the crystallite size in the range of 8.8–57.3 nm, while decrease with the Sm content from 0 to 0.2 owing to a smaller magnetic moment of Sm 3+ ions. The perovskite SmFeO 3 in the composite nanofibers may contribute to a high coercivity due to the interface pinning, lattice distortion and stress in the ferrite grain boundary fixing and hindering the domain wall motion.

The Ba x Sr 1− x Fe 12 O 19 ( x = 0–1) ferrite hollow fibers with diameters of 1 to 2 μm have been prepared by the gel-precursor transformation process. The gel-precursor decomposition and ferrite formation were analyzed by thermo-gravimetric and differential scanning calorimetry, infrared spectroscopy and X-ray diffraction. The Ba x Sr 1− x Fe 12 O 19 ferrite hollow fibers as-prepared were characterized with scanning electron microscopy and vibrating sample magnetometer. The results show that the Ba x Sr 1− x Fe 12 O 19 ( x = 0–1) ferrite hollow fibers are of a solid solution and these fibers with an obvious hollow structure consist of fine hexagonal plate-like particles. Their magnetic properties are mainly influenced by the chemical composition and grain size. With the barium substitution, the specific saturation magnetization and coercivity of the Ba x Sr 1− x Fe 12 O 19 ferrite hollow fibers decrease from 67.1 Am 2 /kg and 443.3 kA/m (for the simple SrFe 12 O 19 ferrite, x = 0) to 56.1 A m 2 /kg and 319.8 kA/m (for the simple BaFe 12 O 19 ferrite, x = 1.0), respectively. The Ba 0.5 Sr 0.5 Fe 12 O 19 ferrite hollow fibers calcined at 1000 °C for 2 h are composed of single-domain grains around 60 nm and exhibit the specific saturation magnetization 63.9 A m 2 /kg and coercivity 416.5 kA/m.

In order to improve the dispersion of detonation nanodiamonds (ND) in aqueous and non-aqueous media, a series of thermal treatments have been conducted in air ambient to modify ND surface. Small angle X-ray scattering (SAXS) technique and high resolution transmission electron microscopy (HRTEM) were introduced to observe the primary size of ND. Differential thermal analysis (DTA), X-ray diffraction (XRD) methodology, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy were adopted to analyze the structure, bonds at surfaces of the treated ND. Malvern instrument Zetasizer3000HS was used for measuring the surface electric potential and the size distribution of ND. As thermal treatments can cause graphitization and oxidization of functional groups at the surface, ND treated at high temperature is correspondingly more negatively charged in an aqueous medium, and the increased absolute value of zeta potential ensures the electrostatic stability of ND particles. Specially, after being treated at a temperature more than 850 K, ND can be well dispersed in various media.

Surface properties of a nanometer-scale diamond prepared from detonation synthesis were discussed and the dispersion of this nanodiamond (ND) in aqueous solutions was actualized utilizing the method of mechanochemical treatment (MCT). While preparing a stable suspension in alkaline aqueous media, the addition of an anionic surfactant, sodium oleate (SO), can increase the absolute value of ND surface zeta potential, strengthen the electrostatic stabilization and improve the hydrophilicity of the particles. Mechanisms of the surfactant adsorption on ND surface were investigated using Fourier Transform Infrared Spectroscopy (FTIR) and the measures of particle size, surface potential and adsorption capacity of SO on particle surface. Interactions of electrostatic, hydrogen bonding, hydration, and hydrophobic have influence on the adsorption behavior of SO. Dispersion efficiency and colloidal stability behavior of ND particles are dominated markedly by the electrostatic, hydration and hydrophobic interactions among the modified particles.

Mechanochemical Modification (MCM) of nanodiamond surface with DN-10 was studied in relation to the performance of nanodiamond in polishing quartz wafers. Results show that the modified nanodiamond is more stable in the pH range 8∼11. A super smooth surface with an average roughness of 0.214 nm was achieved using a nanodiamond-based slurry regulated by N-(2-hydroxyethyl)ethylenediamine. It is suggested that the principal ultra-fine polishing mechanism of quartz wafer involves atom-level removal under the synergism of chemical and mechanical actions.

A simple process has been developed to fabricate the magnetic nanocrystalline porous Co–Fe alloy microfibers with a hollow structure by the sol–gel and phase transformation at a low temperature. The alloy microfibers consisting of nanoparticles about 30 nm are characterized with a fiber diameter around 0.5 μm, a ratio of the hollow diameter to the fiber diameter about 1/2 and pore sizes of 50 to 300 nm. These nanocrystalline porous Co–Fe alloy hollow microfibers have a good magnetic property, with the specific saturation magnetization of 212.8 A m 2 kg −1 and coercivity of 15.6 kA m −1 at room temperature.

The effect of different kinds of surfactants on the size distribution of nanodiamond particles in clean oil was studied. Results show that the dispersing stability of nanodiamond modified with surfactants YS-1 and SB-18 simultaneously is much better than those modified with either of them because of synergism of the surfactants. And the particle size distribution in the system can be improved remarkably after the adoption of hyperdispersants such as SA-E and SA-F. Anchoring groups of those hyperdispersants can be bonded with the particle surface by chemical and/or hydrogen bonding and their soluble chains are well compatible with the dispersion media. As a result, the particles are uniformly distributed in the system owing to the steric stabilization. A very stable clean-oil based nanodiamond suspension with an average particle size of around 53.2 nm was prepared.