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In fluorescence microscopy, computational algorithms have been developed to suppress noise, enhance contrast, and even enable super-resolution (SR). However, the local quality of the images may vary on multiple scales, and these differences can lead to misconceptions, which is especially intractable in emerging deep-learning ones. Current mapping methods fail to finely estimate the local quality, challenging to associate the SR scale content. Here, we develop a rolling Fourier ring correlation (rFRC) framework to evaluate the reconstruction uncertainties down to SR scale. To visually pinpoint regions with low reliability, a filtered rFRC is combined with a modified resolution scaled error map (RSM), offering a comprehensive and concise map for further examination. We demonstrate their performances on various SR imaging modalities, and the resulting quantitative maps enable better SR images integrated from different reconstructions. Beyond that, we provide a strategy for learning-based restorations, allowing a direct detection of both data and model uncertainties, and expect the representative cases can inspire further advances in this rapidly developing field.

A main determinant of the spatial resolution of live-cell super-resolution (SR) microscopes is the maximum photon flux that can be collected. To further increase the effective resolution for a given photon flux, we take advantage of a priori knowledge about the sparsity and continuity of biological structures to develop a deconvolution algorithm that increases the resolution of SR microscopes nearly twofold. Our method, sparse structured illumination microscopy (Sparse-SIM), achieves ~60-nm resolution at a frame rate of up to 564 Hz, allowing it to resolve intricate structures, including small vesicular fusion pores, ring-shaped nuclear pores formed by nucleoporins and relative movements of inner and outer mitochondrial membranes in live cells. Sparse deconvolution can also be used to increase the three-dimensional resolution of spinning-disc confocal-based SIM, even at low signal-to-noise ratios, which allows four-color, three-dimensional live-cell SR imaging at ~90-nm resolution. Overall, sparse deconvolution will be useful to increase the spatiotemporal resolution of live-cell fluorescence microscopy. The resolution of fluorescence microscopy is increased by incorporating prior information into deconvolution algorithms.

In fluorescence microscopy, computational algorithms have been developed to suppress noise, enhance contrast, and even enable super-resolution (SR). The local quality of the images may vary on multiple scales and these differences can lead to misconceptions. However, current mapping methods fail to finely estimate the local quality, challenging to associate the SR scale content. Here, we develop a rolling Fourier ring correlation (rFRC) to quantify reconstruction quality down to the SR scale. To visually pinpoint regions with low reliability, we combine a filtered rFRC with a modified resolution scaled error map (RSM), providing a comprehensive and concise map for further examination. We demonstrate their performances on different SR imaging modalities, and the resulting quantitative maps enable better SR images integrated from different reconstructions. Beyond that, as a model-independent assessment, we show its applications in evaluating the local restoration qualities for the deep-learning methods.

This study evaluates the feasibility of using antenna array to detect crack defects in metal pipes. Antenna arrays are set at the port of a metal pipe in radial direction, and the microwave signal can be effectively coupled into the metal pipe. It can produce orbital angular momentum (OAM) waves. The cracks in the pipe will change the microwave transmission characteristics, and they can be inspected by time domain reflectometry (TDR) of vector network analyzer (VNA). By studying the transmission characteristics of current on the inner surface of the metal pipe, the feasibility of linearly polarized TE11 mode microwaves for crack inspection was preliminarily verified. Three galvanized metal pipes with an inner diameter of 8 cm and a total length of about 270 cm were used in the experiment. Axial slits and circumferential slits were used to simulate the crack, respectively. The slits penetrated the pipe wall with a breach of approximately 10 cm × 0.7 cm . The experimental results demonstrated that the radial direction antenna array can detect both the axial slit and circumferential slit through TDR and standing wave ratio (SWR) at the port, especially effective for the axial slit. It provides a new inspection method for metal pipe defect evaluation.

A novel joining method, i.e., metallic bump assisted resistance spot welding (MBaRSW) was proposed, in which, a third-party aluminum metallic bump was printed on either aluminum alloy or steel sheet through modifying the Fronius cold metal transfer (CMT) pin process, and then a resistance spot weld was made via the bump to solve the problems of low joint strength and severe weld thinning in conventional Al/steel resistance spot welds. This two-part paper aims at investigating the mechanism of the novel RSW process. In this part, Fronius CMT pin process was first investigated to examine its control mechanism on pin-like or bump-like morphology of products, and then an exclusive bump printing process was developed. Results showed that due to better wettability the bumps printed on Al substrate were bigger, shorter and much stronger than that on steel substrate in which intermetallic compound (IMC) layer formed along bump/steel interface. The study laid a foundation for development of the novel Al-steel MBaRSW process.

The spatial resolutions of live-cell super-resolution microscopes are limited by the maximum collected photon flux. Taking advantage of a priori knowledge of the sparsity and continuity of biological structures, we develop a deconvolution algorithm that further extends the resolution of super-resolution microscopes under the same photon budgets by nearly twofold. As a result, sparse structured illumination microscopy (Sparse-SIM) achieves ~60 nm resolution at a 564 Hz frame rate, allowing it to resolve intricate structural intermediates, including small vesicular fusion pores, ring-shaped nuclear pores formed by different nucleoporins, and relative movements between the inner and outer membranes of mitochondria in live cells. Likewise, sparse deconvolution can be used to increase the three-dimensional resolution and contrast of spinning-disc confocal-based SIM (SD-SIM), and operates under conditions with the insufficient signal-to-noise-ratio, all of which allows routine four-color, three-dimensional, ~90 nm resolution live-cell super-resolution imaging. Overall, sparse deconvolution may be a general tool to push the spatiotemporal resolution limits of live-cell fluorescence microscopy.

The terahertz technology has attracted considerable attention because of its potential applications in various fields. However, the research of functional devices, including polarization converters, remains a major demand for practical applications. In this work, a reflective dual-functional terahertz metadevice is presented, which combines two different polarization conversions through using a switchable metasurface. Different functions can be achieved because of the insulator-to-metal transition of vanadium dioxide (VO2). At room temperature, the metadevice can be regarded as a linear-to-linear polarization convertor containing a gold circular split-ring resonator (CSRR), first polyimide (PI) spacer, continuous VO2 film, second PI spacer, and gold substrate. The converter possesses a polarization conversion ratio higher than 0.9 and a bandwidth ratio of 81% in a range from 0.912 THz to 2.146 THz. When the temperature is above the insulator-to-metal transition temperature (approximately 68 °C) and VO2 becomes a metal, the metasurface transforms into a wideband linear-to-circular polarization converter composed of the gold CSRR, first PI layer, and continuous VO2 film. The ellipticity is close to −1, while the axis ratio is lower than 3 dB in a range of 1.07 THz–1.67 THz. The metadevice also achieves a large angle tolerance and large manufacturing tolerance.

A main determinant of the spatial resolution of live-cell super-resolution (SR) microscopes is the maximum photon flux that can be collected. To further increase the effective resolution for a given photon flux, we take advantage of a priori knowledge about the sparsity and continuity of biological structures to develop a deconvolution algorithm that increases the resolution of SR microscopes nearly twofold. Our method, sparse structured illumination microscopy (Sparse-SIM), achieves ~60-nm resolution at a frame rate of up to 564 Hz, allowing it to resolve intricate structures, including small vesicular fusion pores, ring-shaped nuclear pores formed by nucleoporins and relative movements of inner and outer mitochondrial membranes in live cells. Sparse deconvolution can also be used to increase the three-dimensional resolution of spinning-disc confocal-based SIM, even at low signal-to-noise ratios, which allows four-color, three-dimensional live-cell SR imaging at ~90-nm resolution. Overall, sparse deconvolution will be useful to increase the spatiotemporal resolution of live-cell fluorescence microscopy.

This paper proposes a counter-rotating dual-rotor permanent magnet synchronous motor to drive two counter-rotating propellers of a cylindrical underwater vehicle. This can avoid yawing and spinning of the underwater vehicle whilst maintain excellent electromagnetic performance. Because of a direct drive arrangement, the system efficiency of the motor drive is improved as well as the volume and costs. More importantly, the proposed motor has better reliability than conventional underwater dc drive systems owing to the removal of brushes and slip-rings. In electromagnetic design, the pole number, permanent magnet size, stator winding design, and nonmagnetic material are analyzed and optimized. Finally, a 10.8 kW 1000 r/min counter-rotating dual-rotor disc-type PM motor is designed, and its main performance parameters, such as EMF, torque, and mechanical stress, are analyzed, which have confirmed the effectiveness of the rotor design and its application to underwater propulsion applications.

We design a novel negative curvature fiber (NCF) to support terahertz orbital angular momentum (OAM) modes. Numerical models are constructed to evaluate the transmission performances of vector modes in the frequency range of 0.40–0.80 THz. The designed fiber made from only one kind of heat-resistance resin (HTL) material can support 50–52 OAM modes with large effective index differences above 10−4 and low confinement loss (in the level of 10−15 dB/cm). Some other significant characteristics of the designed NCF including waveguide dispersion, OAM purity, and effective mode field area (Aeff), are also calculated and analyzed with their effects and applications on terahertz OAM guidance. The optimized absolute value of dispersion is between 0.33 and 0.8 ps/(THz × cm) in the range of 0.45–0.75 THz. The high mode purity (85%−95%) in the range of 0.60–0.80 THz further promotes the mode division multiplexing in OAM fiber. The proposed NCF can offer great potential in high-capacity terahertz communication based on OAM multiplexing.

To investigate the radiation background level of jijicao block and rock mass around Xinchang section in the pre-selected area of Beishan, northwest China, the relevant soil samples and data have been obtained, and the natural radioactivity of the soil samples has been measured by gamma-ray spectroscopy with hyper-pure germanium detector. The mean activity concentrations of 226Ra, 232Th and 40K in soil samples are determined as 23.72 (from 11.2 to 48.6 Bq.kg-1), 28.72 (from 11.9 to 33.0 Bq.kg-1) and 612.93 Bq.kg-1 (from 244.0 to 907.0 Bq.kg-1), respectively, which are all lower than the Jiuquan background values, among which the concentration of 40K is higher than UNSCEAR 2008 and Beishan background value. The calculated data of radium equivalent, representative level index, external standard, internal standard, and annual effective dose are less than the recommended limits. Therefore, it can be concluded that the building being constructed of the materials is safe for the inhabitants. The findings from this research will be useful to assess the radiation hazards of building materials in humans. It is valuable for the environmental impact assessment of the underground research laboratory of high-level radioactive waste and the assessment of the hazard of radioactive building materials to human body.

A novel double negative curvature terahertz fiber with elliptical tubes as cladding structure is designed and investigated. Six uniformly arranged elliptical hole tubes and six circular tubes are connected to each other as the cladding structure of the fiber. The confinement loss, bending loss, dispersion, and effective mode field area of the fiber are calculated in two different frequency regions. The simulation shows that the lowest confinement loss of 3.2 × 10−6 dB cm−1 can be achieved at 2.44 THz. The confinement loss is always in the order of 10−5–10−6 dB cm−1 in the frequency band of 2.22–2.5 THz. The waveguide dispersion of fiber remains between −0.18 and 0.05 ps/(THz × cm) in the frequency band of 2.04–2.4 THz. Moreover, the bending loss of 4.4 × 10−5 dB cm−1 can be obtained when the bending radius is 25 cm. The debut of this double negative curvature terahertz fiber, with combined advantages of ultralow confinement loss, low bending loss, low and flat dispersion and simple structure forebodes a new approach to completely release the potential of fiber in terahertz applications.

This publisher’s note contains corrections to Opt. Lett. 46, 290 (2021)OPLEDP0146-959210.1364/OL.412229.

At present, most of the gradient metasurfaces used to construct surface plasmon polaritons (SPPs)/spoof SPPs (SSPs) couplers are usually compact metal antennas working under reflection and transmission. In reflection mode, meta-couplers link propagating waves and surface waves (SWs), and SWs will undergo significant scattering before coupling to an Eigen SPP in the target system. In transmission mode, metal meta-couplers will encounter complex multilayer designing at the microwave/terahertz region and metal absorption loss at optical frequencies. In this Letter, to the best of our knowledge, a novel design using dielectric gradient metasurfaces instead of metal metasurface couplers is proposed to excite broadband SSPs on the metal groove array. We demonstrate that the well-designed phase dielectric gradient metasurface converts the normal incident terahertz wave to the predetermined angle in the dielectric substrate and then excites the broadband SSPs with the transmission coupling between the dielectric meta-coupler and SSPs surface. This research may open up new avenues in simple and broadband plane dielectric meta-couplers for SSPs in ultra-thin and compact functional devices for versatile applications.

Dielectric meta-gratings have achieved tremendous success in realizing high-efficiency wavefront control in terahertz range. Here, several efficient, polarization-insensitive, low-cost devices are investigated numerically and experimentally. First, an anomalous deflector based on a low-index polymer acrylonitrile butadiene styrene meta-grating is designed and measured around 0.1 THz. By breaking the distance limitation between the fixed bars and bending the terahertz beam into the T−1 diffraction order through the optimization of quadrumer unit cell, the efficiencies for 37° deflection under normal excitation reach 67.1% (56.4%) with the S-(P-) polarized terahertz wave, which are in good agreement with the simulated 71.8% (63.7%). Next, with regard to the concept of bending light by the proposed meta-grating array, a method for designing a terahertz flat lens is proposed and experimentally demonstrated with long focal length and polarization insensitivity. The proposed flat lens can achieve the measured numerical aperture of 0.604 (collection angle of 37.2°.) and focusing efficiency of 50.3% with normal incident of linear polarized terahertz wave at 0.1 THz. Also, a focal spot with the focusing distance of 65.9 mm is achieved. These designs can be manufactured by 3D printing at low cost, and provide promising applications in imaging, communication, information processing and materials science.

Deep displacement monitoring of rock and soil mass is the focus of current geological hazard research. In the previous works, we proposed a geophysical deep displacement characteristic information detection method by implanting magneto-electric sensing arrays in boreholes, and preliminarily designed the sensor prototype and algorithm of deep displacement three-dimensional (3D) measurement. On this basis, we optimized the structure of the sensing unit through 3D printing and other technologies, and improved the shape and material parameters of the permanent magnet after extensive experiments. Through in-depth analysis of the experimental data, based on the data query algorithm and the polynomial least square curve fitting theory, a new mathematical model for 3D measurement of deep displacement has been proposed. By virtue of it, the output values of mutual inductance voltage, Hall voltage and tilt measuring voltage measured by the sensing units can be converted into the variations of relative horizontal displacement, vertical displacement and axial tilt angle between any two adjacent sensing units in real time, and the measuring errors of horizontal and vertical displacement are tested to be 0&ndash, 1.5 mm. The combination of structural optimization and measurement method upgrading extends the measurement range of the sensing unit from 0&ndash, 30 mm to 0&ndash, 50 mm. It shows that our revised deep displacement 3D measuring sensor can better meet the needs of high-precision monitoring at the initial stage of rock and soil deformation and large deformation monitoring at the rapid change and imminent-sliding stage.

Underground displacement monitoring is a key means to monitor and evaluate geological disasters and geotechnical projects. There exist few practical instruments able to monitor subsurface horizontal and vertical displacements simultaneously due to monitoring invisibility and complexity. A novel underground displacement 3D measuring sensor had been proposed in our previous studies, and great efforts have been taken in the basic theoretical research of underground displacement sensing and measuring characteristics by virtue of modeling, simulation and experiments. This paper presents an innovative underground displacement joint inversion method by mixing a specific forward modeling approach with an approximate optimization inversion procedure. It can realize a joint inversion of underground horizontal displacement and vertical displacement for the proposed 3D sensor. Comparative studies have been conducted between the measured and inversed parameters of underground horizontal and vertical displacements under a variety of experimental and inverse conditions. The results showed that when experimentally measured horizontal displacements and vertical displacements are both varied within 0 ~ 30 mm, horizontal displacement and vertical displacement inversion discrepancies are generally less than 3 mm and 1 mm, respectively, under three kinds of simulated underground displacement monitoring circumstances. This implies that our proposed underground displacement joint inversion method is robust and efficient to predict the measuring values of underground horizontal and vertical displacements for the proposed sensor.

Rationale: Oncogenic STAT3 signaling activation and 3p22-21.3 locus alteration are common in multiple tumors, especially carcinomas of the nasopharynx, esophagus and lung. Whether these two events are linked remains unclear. Our CpG methylome analysis identified a 3p22.2 gene, DLEC1, as a methylated target in esophageal squamous cell (ESCC), nasopharyngeal (NPC) and lung carcinomas. Thus, we further characterized its epigenetic abnormalities and functions. Methods: CpG methylomes were established by methylated DNA immunoprecipitation. Promoter methylation was analyzed by methylation-specific PCR and bisulfite genomic sequencing. DLEC1 expression and clinical significance were analyzed using TCGA database. DLEC1 functions were analyzed by transfections followed by various cell biology assays. Protein-protein interaction was assessed by docking, Western blot and immunoprecipitation analyses. Results: We defined the DLEC1 promoter within a CpG island and p53-regulated. DLEC1 was frequently downregulated in ESCC, lung and NPC cell lines and primary tumors, but was readily expressed in normal tissues and immortalized normal epithelial cells, with mutations rarely detected. DLEC1 methylation was frequently detected in ESCC tumors and correlated with lymph node metastasis, tumor recurrence and progression, with DLEC1 as the most frequently methylated among the established 3p22.2 tumor suppressors (RASSF1A, PLCD1 and ZMYND10/BLU). DLEC1 inhibits carcinoma cell growth through inducing cell cycle arrest and apoptosis, and also suppresses cell metastasis by reversing epithelial-mesenchymal transition (EMT) and cell stemness. Moreover, DLEC1 represses oncogenic signaling including JAK/STAT3, MAPK/ERK, Wnt/β-catenin and AKT pathways in multiple carcinoma types. Particularly, DLEC1 inhibits IL-6-induced STAT3 phosphorylation in a dose-dependent manner. DLEC1 contains three YXXQ motifs and forms a protein complex with STAT3 via protein docking, which blocks STAT3-JAK2 interaction and STAT3 phosphorylation. IL-6 stimulation enhances the binding of DLEC1 with STAT3, which diminishes their interaction with JAK2 and further leads to decreased STAT3 phosphorylation. The YXXQ motifs of DLEC1 are crucial for its inhibition of STAT3 phosphorylation, and disruption of these motifs restores STAT3 phosphorylation through abolishing DLEC1 binding to STAT3. Conclusions: Our study demonstrates, for the first time, predominant epigenetic silencing of DLEC1 in ESCC, and a novel mechanistic link of epigenetic DLEC1 disruption with oncogenic STAT3 signaling in multiple carcinomas.

The perishable product’s dynamic pricing with quantity discount strategy is studied. The seller uses two-period dynamic price during the whole sale period and introduces quantity discount in second sale period in order to improve the seller’s proflt. The mathematic model expressions are obtained by assuming that consumer’s reservation price draws from a uniform distribution and the price discount is the linear function of the consumer’s proportion that purchased two units product in the second period. The models provide insights about optimal price and price discount under difierent levels of the number of the potential consumers, salvage value, reservation price. Finally, Matlab is used to implement the numerical studies and sensitivity tests. We flnd that the seller’s proflt increases efiectively after using quantity discount strategy through raising the two-period price and lowering the remaining inventory. The efiectiveness of the quantity discount depends heavily on the number of potential consumers, the product’s salvage value, the difierence between highest and lowest reservation price.

Due to high-speed rotation, the problems about rotor mechanics and dynamics for outer rotor high-speed machine are more serious than conventional ones, in view of above problems the mechanical and dynamics analysis for an outer rotor high-speed permanent magnet claw pole motor are carried out. The rotor stress analytical calculation model was derived, then the stress distribution is calculated by finite element method also, which is coincided with that calculated by analytical model. In addition, the stress distribution of outer rotor yoke and PMs considering centrifugal force and temperature effect has been calculated, some influence factors on rotor stress distribution have been analyzed such as pole-arc coefficient and speed. The rotor natural frequency and critical speed were calculated by vibration mode analysis, and its dynamics characteristics influenced by gyroscope effect were analyzed based on Campbell diagram. Based on the analysis results above an outer rotor permanent magnet high-speed claw pole motor is design and verified.

In order to avoid environmental pollution from Coal gangue (CG) and copper tailings (CT), the utilization as cement clinker calcinations was experimentally investigated. Low-calcium limestone was also selected as another raw material. The clinker component and microstructure were analyzed by XRD and SEM. The experimental results showed that qualified cement clinker could be generated by substituting CG and CT compound for clay. While mixed with high-calcium limestone and low-calcium limestone, the calcinations temperature were 50 °C or 100 °C lower than that of clay. CT and CG contain oxygen-rich minerals and potential of geological rock energy. The energy of CG performs functions and drops down sintering temperature. The calcination time was shortened and the clinker sintering coal consumption reduced while substituting CG and CT for clay, and also served the reutilization of low-calcium limestone, CG and CT.

Epigenetic inactivation of RASSF1A, a putative tumor suppressor with proapoptotic activity, is frequently observed in a number of solid tumors, including a variety of epithelial cancers, but has not been described in hematopoietic tumors. We have analysed the expression and methylation status of RASSF1A in Hodgkin's lymphoma (HL)-derived cell lines, primary HL tumors and serum samples from HL patients. RASSF1A transcription was detectable in only 2/6 HL cell lines. Methylation-specific PCR and bisulfite genomic sequencing revealed that the RASSF1A promoter was hypermethylated in all four RASSF1A-nonexpressing cell lines. 5-aza-2'-deoxycytidine treatment resulted in demethylation of the promoter and RASSF1A expression in these lines. Hypermethylation of RASSF1A was also detected in 34/52 (65%) primary HL tumors and in 2/22 serum samples from these patients. Microdissection of Hodgkin/Reed-Sternberg (HRS) cells from several of these cases confirmed that the RASSF1A hypermethylation we detected in the analysis of whole tumor originated from the tumor cell population. Although hypermethylation of RASSF1A was detected in 5/6 non-Hodgkin's lymphoma (NHL)-derived cell lines, only rare primary NHL (1/10 of Burkitt's lymphoma, 1/12 of post-transplant lymphoma, 1/12 diffuse large B-cell lymphoma, 0/27 of nasal lymphoma, 0/8 follicular center cell lymphoma, 0/4 mantle cell lymphoma, 0/4 anaplastic large cell (Ki-1+) lymphoma, 0/2 MALT lymphoma) showed hypermethylation of the promoter. No methylation was detected in any of the 14 normal PBMC. These results point to an important role for epigenetic silencing of RASSF1A in the pathogenesis of HL. Inactivation of RASSF1A could be one mechanism by which HRS cells escape the apoptosis that should occur following nonproductive immunoglobulin gene rearrangements.

Underground displacement monitoring is an effective method to explore deep into rock and soil masses for execution of subsurface displacement measurements. It is not only an important means of geological hazards prediction and forecasting, but also a forefront, hot and sophisticated subject in current geological disaster monitoring. In previous research, the authors had designed a novel electromagnetic underground horizontal displacement sensor (called the H-type sensor) by combining basic electromagnetic induction principles with modern sensing techniques and established a mutual voltage measurement theoretical model called the Equation-based Equivalent Loop Approach (EELA). Based on that work, this paper presents an underground displacement inversion approach named “EELA forward modeling-approximate inversion method”. Combining the EELA forward simulation approach with the approximate optimization inversion theory, it can deduce the underground horizontal displacement through parameter inversion of the H-type sensor. Comprehensive and comparative studies have been conducted between the experimentally measured and theoretically inversed values of horizontal displacement under counterpart conditions. The results show when the measured horizontal displacements are in the 0–100 mm range, the horizontal displacement inversion discrepancy is generally tested to be less than 3 mm under varied tilt angles and initial axial distances conditions, which indicates that our proposed parameter inversion method can predict underground horizontal displacement measurements effectively and robustly for the H-type sensor and the technique is applicable for practical geo-engineering applications.

2–3 anti-fungal disease genes are coinserted with hygromycin phosphotransferase in the same vector. Two insecticidal genes and PPT acetyl transferase genes are placed in another one. The vectors are co-delivered to rice embryonic cellus tissue at a molar ratio of 1 : 1 using the particle gun method. 55 independent regenerated lines have been obtained through screening for hygromycin resistance. Of these, 70% transgenic plants harbor 6–7 foreign genes. The genes on the same vectors are always co-delivered to rice plant. Northern blot analysis has indicated that the multiple foreign genes give stable expression. In the 6 transgenic plants carrying 6–7 foreign genes, multiple foreign genes tend to integrate in 1 or 2 genetic loci. Progeny segregation is consistent with Mendel’s 3 : 1 segregation law. 8 homozygous R1 transgenic plants harboring 2–3 anti-fungal and 2 insecticidal genes are selected from large number of transgenic progeny screening for hygromycin and Basta resistance.

Ti–Al–Si–Nb dual phase alloys are mainly composed of α 2 -Ti 3 Al matrix and Ti 5 Si 3 silicide phases. In this paper, two alloys (402 and 405) whose Si contents are 2 and 5 at% respectively were arc melted and hot-rolled into sheets with different amounts of deformation. The silicide phase (Ti,Nb) 5 (Si,Al) 3 was broken up into small pieces and redistributed in the α 2 matrix during the hot-rolling. Improved strength and ductility of the two alloys were observed after hot-rolling, which can be attributed to both the finely distributed reinforcement silicide phase and refinement of the matrix grain size. The mechanical properties of the two alloys are dependent on their volume fractions of the silicide phase: the strength of alloy 405 is higher than that of alloy 402, while alloy 402 is more ductile than alloy 405. The brittle–ductile transition temperature of the two dual phase alloys is between 600 and 800°C. The surface slip on the dual phase alloys was also observed. Obvious separation between the (Ti,Nb) 5 (Si,Al) 3 particles and the α 2 matrix is found on the fracture surfaces obtained at high temperature, showing dimple-like morphology.

The oxidation kinetics of the Ti3Al based alloys with Nb (0 to 20 at%) or Si (0 to 15 at%) addition was carefully measured at 800 and 900°C, respectively. The oxide scale was characterised by high temperature in-situ XRD, SEM, EPMA and conventional XRD. The weight gains of the alloys were greatly reduced by Nb or Si addition. The improvement of the oxidation resistance in the Ti3Al alloys by Nb addition is attributed to the formation of a compact scale. The formation of a compact scale is favoured not only by doping effect but also by the TiN layer which barriers the outward Al diffusion into the scale to form porous intermixed titania/alumina. Si addition promotes the formation of a compact TiO2 layer in the oxide scale and the formation of SiO2, thus the oxidation resistance of the Ti3Al based alloys is improved. The oxidation behaviour of the alloys with Si addition is a combinative function of the α2-Ti3Al matrix and the Ti5Si3 silicide phase.

The cyanobacterium Spirulina platensis was tested for sensitivity to 6 antibiotics: kanamycin (Km), neomycin (Neo), geneticin (G418), ampicillin (Ap), chloramphenicol (Cm), hygromycin (Hm) and to 1 herbicide: L-phosphinothricin (PPT), all of which are frequently applied as selectable markers in plant gene engineering. Growth tests, carried out at different concentrations of the agents above, showed that S. platensis was sensitive to Hm, Cm and PPT, while highly resistant to Km, Neo, G418 and Ap, indicating that Hm, Cm and PPT were potent inhibitors of S. platensis growth and able to be employed as selectable markers for further transformation studies for this alga.

To investigate the methodology to inhibit DNase activity in the cyanobacterium Spirulina, the effects of Mg2+ on the growth and DNase activity of Spirulina platensis strain SSP-14 were studied. The results indicated that strain SSP-14 could keep growing, but much slower, when inoculation and cultivation were done twice in Mg2+/free Zarrouk medium; and the activity of both intracellular and extracellular DNases was almost completely inhibited. This manipulation could efficiently remove the high-level activity of DNases which frequently exist in Spirulina and block foreign genes from being introduced. It is recommended that the technique be applied for genetic transformations of this alga.

The addition of 11 at% Nb or 5 at% Si can improve the oxidation resistance of TiAl{sub 3}. The effect of the combined addition of Nb and Si is even better. No continuous protective Al{sub 2}O{sub 3} layer was formed after the addition of 11 at% Nb, 5 at% Si or the combined addition of Nb and Si. The beneficial effect of the addition of Nb, Si or the combination of them is probably due to the formation of TiN and the reduction of porosity in the oxide scale.

In this paper, following the idea of dual phase alloys, the authors dealt with the TiAl based Ti-Al-Si ternary alloys. The investigation was carried out to understand the basic properties of these alloys. Emphasis was placed on the relationship between microstructures and mechanical properties. Their present study has shown that a sufficient Si addition to the TiAl matrix resulted in TiAl + Ti{sub 5}Si{sub 3} dual phase alloys. The microstructure was coupled-growth in general which could be characterized as eutectic, hypoeutectic and hypereutectic. The second phase Ti{sub 5}Si{sub 3} contributed to the enforcement of the matrix, which was the expected result. However, high Si and Al contents resulted in low ductility and fracture strength. This was because of the coarse Ti{sub 5}Si{sub 3} primary phases and the embrittlement of the matrix. So in the view of alloy design, emphasis should be placed on the hypoeutectic and eutectic alloys, and adjusting the amount and shape of Ti{sub 5}Si{sub 3} in the Ti rich TiAl matrix may shed some light on their practical use in the future.

Dual phase alloys Ti + Ti{sub 5}Si{sub 3} or Ti{sub 3}Al + Ti{sub 5}(Si,Al){sub 3} are recently of special interest, due to their probable high performance at elevated temperatures. In 1988, a eutectic line of Ti{sub 3}(Al,Si) + Ti{sub 5}(Si,Al){sub 3} was first established in a Ti-rich portion of the Ti-Al-Si system, and was further reported in the following years. However, the reported line only covered a limited range in the Ti-Al-Si ternary system; thus, extensive study over a wider range in the ternary phase diagram is necessary. In the present paper, the details of the {beta}-Ti(Al,Si) + Ti{sub 5}(Si,Al){sub 3} eutectic line, ranging from 0 at% Al to 40 at% Al will be reported, together with the melting temperatures and the microstructures of the eutectic alloys. It is suggested that the eutectic line in this paper means the liquidus valley between {beta}-Ti-rich liquidus surface and Ti{sub 5}Si{sub 3}-rich liquidus surface, while the eutectic microstructure, here, means the coupled-growth microstructure solidified along this liquidus valley.

Through the analysis of causes of technological lock-in and the use of tools like knowledge map, this essay recommends on how to break away from the technological lock-in for our domestic industry and engages in the design of model related to R&D knowledge management system from the aspect of improving firm's R&D knowledge management level, increasing R&D efficiency and incorporating market information in R&D proceed.