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This article proposes a methodology for designing co-polarized in-band full-duplex (IBFD) antenna arrays with high isolation. An equivalent circuit model of IBFD antenna arrays is established, and transmission zeros are introduced by configuring controllable coupling paths between the arrays. Based on the proposed equivalent circuit model, the high-isolation co-polarized IBFD antenna arrays are designed by utilizing a wavefront phase compensation technique and a controllable coupling structure. Two co-polarized IBFD cavity slot antenna arrays based on the TM510 mode cavity are designed for validation, where a transmission zero is obtained in the passband to improve the isolation between the transmitter (Tx) and the receiver (Rx) ports. Compared with the reference antenna array, the isolation of the designed IBFD antenna array is improved by about 22 dB. The theoretical analysis and design process of the IBFD antenna array is given in detail. A second-order co-polarized IBFD antenna array is fabricated and measured, and the measured results are in good agreement with the simulated results.

The effects of Cu content and heat treatment process on the microstructures and mechanical properties of a series of Al−Si−Mg−Mn−xCu cast aluminum alloys prepared by the vacuum die casting process were investigated by three-dimensional X-ray microscopy, optical microscopy, scanning electron microscopy, transmission electron microscopy and microhardness testing. It was found that the number density and size of gas porosities increase with increasing Cu content. However, the Cu addition will promote the formation of Cu-containing primary phases (Q-Al5Cu2Mg8Si6and θ-Al2Cu) during the solidification, which will improve the properties of the alloys. Five different primary phases were observed, namely eutectic Si, α-Al(Fe, Mn)Si, β-Mg2Si, Q-Al5Cu2Mg8Si6, and θ-Al2Cu phases. With increasing the Cu content, the θphase area fraction increases significantly, while the α-Al(Fe, Mn)Si phase area fraction decreases initially, followed by a slight increase, with the Qphase area fraction displaying the opposite trend relative to α-Al(Fe, Mn)Si phase. These primary phases present different evolution rules during heat treatment process. During subsequent aging, the synergic effect of precipitating Q'and θ'phases can significantly increase the alloy hardening response.

In this communication, a compact waveguide filtering antenna is designed using dual-post coaxial resonators. The dual-post coaxial resonator consists of a pair of identical metal posts, capable of generating two resonant modes with identical and opposite electric field directions, respectively. The coupling post structure is employed to excite the two modes to achieve positive coupling and negative coupling. The combination of different dual-post coaxial resonators can be used to design higher order filters with transverse topology, realizing multiple transmission zeros. Furthermore, additional transmission zeros can be generated through direct coupling between the source and load, resulting in enhanced out-of-band rejection performance. A fourth-order waveguide filtering antenna is fabricated and measured, achieving high-selectivity performance.

This article proposes a novel concept of a strongly coupled radiator that can achieve different phase shift characteristics by choosing different operating states. The strongly coupled structure is realized by introducing a strong coupling in the second-order filter topology, which can be equivalent to two first-order topologies with different phase responses. The topology of strongly coupled radiators and their filtering responses are analyzed in detail. Based on this concept, a strongly coupled radiating metal block antenna is designed, which has the same radiation characteristics as the conventional first-order radiant metal blocks, but with antiphase characteristic. This feature can be utilized to design high-order mode cavity antenna array with low sidelobe and high gain. For verification, a third-order filtering antenna array is designed and fabricated using a TE501 mode cavity, three strongly coupled radiating metal blocks and two conventional radiating metal blocks. The measured results show high gain and low sidelobe level.

This communication implements a series-fed microstrip patch antenna with slant polarization. A 45° inclined cross-shaped dual-polarized microstrip patch antenna array was investigated. The radiating elements are interconnected with conductive strips to minimize the influence of the out-of-phase phase currents on the radiation pattern, thus significantly improving the broadside directivity of the antenna. A novel structure miniaturization scheme is proposed. The conductive strips are meandered to reduce the size of the antenna and the proposed antenna is designed. A pair of differential power dividers is utilized to replace the complex feeding network of the normal antenna array, thus simplifying the structure of the antenna. A prototype is then fabricated and measured to verify our design. The results show that the proposed dual-polarized three-element array operates from 3.4 to 3.6 GHz with the advantages of high gain, simple feeding, and low loss, which is attractive in high-directivity and dual-polarization applications.

This brief describes a method of designing coaxial wide-range tunable filter with constant absolute bandwidth (CABW). The slots placed on the top of the coaxial resonator and the tuning element form an interdigital structure to enlarge loading capacitance, which extends the tuning range of the coaxial cavity resonant frequency. Based on this resonator, novel input/output (I/O) and inter-resonator (IR) coupling structures are proposed to meet the requirements of the CABW of the tunable filter. A fourth-order inline bandpass filter is designed for verification. Furthermore, methodology of designing cascaded-quartet (CQ) configuration filter with two transmission zeros (TZs) is proposed. The fabricated inline filter exhibits a wide tuning range from 590 MHz to 765 MHz (25.8%), over which the absolute bandwidth (ABW) variation is within 16.2±1.2 (±7.4%) MHz while the CQ-configuration filter provides a tuning range from 565 MHz to 765 MHz (30.1%) over which the ABW variation is within 15.285±0.335 MHz (±4.4%).

Here, a wideband two-port co-linearly polarized stacked patch antenna is investigated for in-band full-duplex (IBFD) applications. The initial antenna structure is composed of a single patch element and a pair of metallic probes. A mutual coupling dip is visibly observed in the band of interest without an extra decoupling structure. To further broaden the working and decoupling bandwidths, a stacked patch is introduced to obtain wideband characteristics of the antenna. Two transmission nulls occur in the passband at the same time. Characteristic mode analysis (CMA) is used to elucidate the detailed decoupling mechanism. A proof-of-concept prototype is fabricated and measured. The measured results show that the proposed antenna operates from 3.23 to 4.26 GHz, and the isolation between the two ports is higher than 20 dB over the working band.

In this article, a decoupling network is proposed for the design of in-band full-duplex antennas, whereby high isolation between the transmitter (Tx) and receiver (Rx) ports is attained by adjusting the coupling within the antenna to generate transmission zeros in the passband. To guide antenna design, analyses are carried out on both first-order and third-order decoupling networks. A first-order full-duplex antenna is designed based on a slot antenna array and a metal block antenna, which are capable of obtaining a transmission zero in the passband. A third-order full-duplex antenna is designed based on a TM120/210 mode cavity and a cross-shaped radiant metal block, which obtains three transmission zeros in the passband. The internal coupling relationships of the antennas are analyzed in detail, and two full-duplex antennas are fabricated and measured. The measured results demonstrate that the isolation between the Tx antenna and Rx antenna is greater than 30 dB in the passband.

In order to solve the problem of large sidelobes in traditional high-order mode cavity slot antenna design, an effective method based on wavefront phase compensation is proposed in this article. Two compensation methodologies, wavefront phase advance and wavefront phase lag, are given and analyzed in detail. By combining the two compensation methods, the wavefronts of adjacent elements with opposite phases can be transformed into those with the same phase, achieving a broadside beam. In addition, the relationship between the directivity and radiation quality factor of the radiation structure is discussed in detail, which is used to solve the problem of different gains of the radiation elements in the array. For verification, a first-order filtering antenna array with five elements and a fifth-order filtering antenna array with ten elements are designed using the TE501 mode cavity. The fifth-order filtering antenna array is fabricated and measured. The measured gain in the passband is stable and the maximum gain is 17.3 dBi. The simulated results are in good agreement with the measured ones, which indicates that the proposed method can be used to design a filtering cavity slot antenna array with high gain and low sidelobes.

In this article, new resonant coupling structures are proposed for designing miniaturized waveguide bandpass filters. The resonant coupling structure is constructed by adding one or two metal blocks in a relatively thick inductive iris, which can be considered as the integration of a resonator, the input, and output coupling structures. Positive or negative coupling can be realized by selecting a different number of metal blocks. The combination of different resonant coupling structures can be used to design higher-order filters with various transverse topologies, realizing different transmission zeros (TZs) distributions. In addition, the weak source–load coupling caused by the resonant coupling structures can introduce an additional TZ, which can further improve the out-of-band suppression level of the filter. For verification, two third-order waveguide bandpass filters based on all resonant coupling structures are designed and simulated to achieve different TZ distributions. Finally, a fifth-order waveguide bandpass filter employing both resonant coupling structures and classical rectangular cavities is designed and fabricated. The measured results verify the proposed method.

The fall armyworm, Spodoptera frugiperda(J.E. Smith) (Lepidoptera, Noctuidae), is a polyphagous and highly destructive agricultural pest that invaded mainland China in 2019. To facilitate research on this pest, it is important to formulate and formalize a suitable artificial diet based on local ingredients. In this study, the life histories of fall armyworm reared on corn leaves and four artificial diets were recorded. The four artificial diets used were: soybean and sucrose-based (SS), soybean and wheat germ-based (SW), chickpea and wheat germ-based (CPW), and corn and soybean-based (CNS). The intrinsic rates of increase were 0.1957, 0.1981, 0.1816, 0.1748, and 0.1464 per day in the fall armyworm populations fed corn leaves, CNS, SW, CPW, and SS, respectively. The highest fecundity (F= 1225.4 eggs per female) and net reproduction rate (R0= 544.7 offspring per individual) were observed for the fall armyworm reared on the CNS diet. Moreover, the developmental rate, survival rate, and fecundity were used to calculate the projection of the population growth. Projection results showed that the fall armyworm populations can increase considerably faster when fed the CNS diet compared with the other diets. In addition, the mass-rearing system showed that the most efficient and economical strategy would be to rear the fall armyworm on the CNS diet. The results indicated that the CNS diet was the most suitable diet for the fall armyworm mass rearing.

Hydrothermal reactions of N,N′-di-3-pyridyladipoamide (L) with 1,2,4,5-benzenetetracarboxylic acid (1,2,4,5-H2btec) in water without and with NaOH afforded [Co(L)(1,2,4,5-btec)0.5]n, 1, and [Co(L)(1,2,4,5-btec)0.5(H2O)2]n, 2, respectively, while immersion of 1into water at room temperature gave {[Co(L)0.5(1,2,4,5-btec)0.5(H2O)4]·2H2O}n, 3, which have been structurally characterized. Complexes 1–3display a 2-fold interpenetrated 3D framework, a unique 2D layer, and a 1D chain, respectively. While complexes 1and 2adopt the same point symbol of (4.64.8)2(42.62.82) for nets, they differ in the vertex symbols that are [4.86.6.6.6.6][4.4.62.62.82.82] and [4.810.6.6.6.6][4.4.62.62.810.810], respectively. Complexes 1–3form a unique series of mixed-ligand coordination polymers that show 3-, 2-, and 1D structures, respectively, and differ in the bonding mode of the anionic polycarboxylate as well as the conformations of the neutral Lligand. Irreversible and temperature-dependent structural changes from 1to 2and 3are observed, demonstrating the disentanglement of 1upon water coordination at various temperatures, which can be ascribed to the variable bonding mode of 1,2,4,5-btec4–and the flexible nature of L.

The ongoing outbreak of Coronavirus Disease 2019 (COVID-19) has spread rapidly throughout China and other countries, and has been characterized as a pandemic. With the strict prevention and control measures implemented by the Chinese government, the spread of the epidemic in China has come under preliminary control by the end of February, 2020, whereas the situation of some countries outside China is not optimistic and raises great public concern. In fighting COVID-19, radiologic examinations played a critical role in the early diagnosis of COVID-19, and could also help assess disease course and severity. There is an urgent need to share useful experience and effective measures internationally. This article outlines the collaborative actions and efforts by the Chinese radiology field and the situation of front-line health care workers in radiology departments to present the world with experiences and examples of Chinese radiology during the COVID-19 outbreak.

A 3D thermo-elasto-hydrodynamic (TEHD) model is presented to study the effects of triangular dimples on the loadcarrying capacity, leakage and friction of a mechanical seal operated under mixed or full film lubrication conditions. The model is solved by the finite element method (FEM), which takes into account the effects of the Jakobsson-Floberg-Olsson (JFO) cavitation boundary condition, surface roughness, elastic-plastic contact, thermo-elastic deformation, and the temperature-viscosity relation. The numerical results of the TEHD model are quite different from those of the hydrodynamic (HD) and thermo-hydrodynamic (THD) models, especially at high speeds. In order to obtain the optimum shape and distribution of the triangular dimples, a comparative study is conducted to investigate different distributions of equilateral triangles and isosceles right triangles. The results show that a surface textured mechanical seal with isosceles right triangular dimples has the most significant hydrodynamic and pumping effects which, in turn, are beneficial to sealing face opening behavior and leakage limitation. The theoretical results are in good agreement with the experimental ones, and offer new guidance for the future design and development of high-speed mechanical seals for aviation piston pumps.

Advanced and metastatic THCA patients usually have a poor prognosis. Thus, this study aimed to establish a risk model to discriminate the high risk population. The expression and clinical data were obtained from TCGA database. The cluster analysis, lasso, univariate and multivariate cox analyses were used to construct risk model. K-M, ROC and DCA were applied to validate the efficiency and stability of the model. GO, KEGG, and ssGSEA analysis were performed to identify the potential mechanism of signatures. The 7-gene prognosis model was constructed, including FAM27E3, FIGN, GSTM4, BEX5, RBPMS2, PHF13, and DCSTAMP. ROC and DCA results showed our model had a better prognosis prediction performance than other risk models. The high risk score was associated with the poor prognosis of THCA patients with different clinical characteristics. The risk score was closely related to cell cycle. Further, we found that the expressions of signatures were significantly dysregulated in THCA and associated with prognosis. These gene expressions were affected by some clinical characteristics, methylation and CNV. Some signatures played a role in drug sensitivity and pathway activation. We constructed a 7-gene signature model based on the integrin-related genes, which showed a great prognostic value in THCA.

Auxin (mainly indole-3-acetic acid, IAA) is one of the most essential phytohormones with various roles for land plants at different evolution stages and its polar transportation in plants suggested the importance of obtaining its amounts in different plant tissues. Because Marchantia polymorphais at the entry evolution level, the IAA contents in its tissues would be useful for the study of IAA evolution. Although electrochemical detection offers a possible method for the measurement of IAA amounts, the cost for fabrication of electrochemical sensors is still high given the amounts of IAA tests in the future. Herein a low-cost disposable electrochemical analytical platform was constructed for analysis of IAA in tiny plant samples. Specifically, disposable carbon electrodes were prepared by modifying stainless steel wire mesh with inexpensive carbon ink because of less amounts of materials. The electrode was then integrated with a paper-based analytical device to form a disposable and low-cost platform for rapid electrochemical detection of IAA. For the modified electrode, the highest electrochemical responses for IAA could be obtained when the carbon ink was diluted for 3.5 times. The optimized pH value of the buffer solution for testing was 7.0, which is close to the physiological condition. Coupled with sample treatment using zirconium beads, this approach could successfully differentiate IAA in different tissues of Marchantia polymorpha. The obtained results agreed well with previous reports. This study suggested a sustainable electrochemical analytical detection platform for the study of IAA in practical applications.

Four coordination polymers constructed from the flexible isomeric bis-pyridyl-bis-amide (bpba) ligands, N,N′-di(3-pyridyl)suberoamide (L1) and N,N′-di(4-pyridyl)suberoamide (L2), and the auxiliary 1,4-naphthalenedicarboxylic acid (1,4-H2NDC), including [Co(L1)1.5(1,4-NDC)(H2O)]n, 1, [Co3(L1)1.5(1,4-NDC)3(EtOH)]n, 2, {[Co(L2)1.5(1,4-NDC)]·H2O}n, 3, and {[Co(L2)0.5(1,4-NDC)]·EtOH}n, 4, have been synthesized and structurally characterized by using single crystal X-ray crystallography. Complex 1forms a two-dimensional layer with double edges and 2exhibits a unique three-dimensional (3D) self-catenated framework with the (48.66.8)-6T60 topology, while 3displays a 3D framework with the highest 5-fold interpenetration for the bnntopology and 4shows a 3D 2-fold interpenetrated framework with the pcutopology. The donor atom positions of the L1and L2ligands and the identity of the solvents play important roles in determining the structural diversity. Moreover, irreversible structural transformation from 2to 1has been verified by immersing crystals of 2into water. The coordination ability of the CH3CH2OH molecule in 2and the thermal stability of 1govern the irreversible structural transformation.

Semi-solid squeeze casting (SS-SC) is a new processing technology which combines semi-solid processing (SSP) and squeeze casting (SC). In this process, semi-solid slurry fills mold by using its rheological property and solidifies under high pressure. It has several advantages, such as stable filling, small heat impact to the mold, low cost, high density and excellent mechanical properties of castings, which receives more and more attention. The microstructure of castings provided by SS-SC is quite different from that of casting provided by conventional SC in as-cast condition, which leads to differences in the evolution of microstructure and mechanical properties in heat treatment process. In this study, A356.2 aluminum alloys castings were provided by both SS-SC and conventional SC respectively. The evolution of microstructure and mechanical properties of castings during heat treatment was investigated to obtain the best mechanical properties of semi-solid squeeze castings. Keywords:Microstructure, Mechanical properties, Heat treatment, A356 alloy, Semi-Solid Squeeze Casting

The rheological characteristics of the oil film on the rod-seal interface in the sealing zone have a major influence on the behavior of reciprocating seals. Because of the addition of polymers, the viscosity and temperature properties of hydraulic oil have improved and the fluid presents non-Newtonian characteristics. To investigate the influence of these characteristics on seal behavior, a soft elastohydrodynamic lubrication (EHL) numerical model is introduced to simulate a step seal under a mixed lubrication condition. A modified Reynolds equation is derived for calculating the fluid film pressure distribution more accurately. The equation is based on the power law fluid model and Jakobsson-Floberg-Olsson (JFO) cavitation theory. Results are presented to gain insight into the effect of non-Newtonian fluid characteristics on seal behavior, and the simulated results are compared to those of a Newtonian fluid to reveal the seal mechanism. The influence of operating parameters and the seal surface root mean square (RMS) roughness on sealing performance under different power law indexes is also investigated and discussed.

Many compounds used as battery storage electrodes undergo large composition changes during use that are accompanied by a first-order phase transition. Most studies of these phase transitions have focused on the unit cell to single-crystallite scale, whereas real battery electrodes are typically composed of mesoscopic assemblies of nanocrystallites, for which phase transformation mechanisms are poorly understood. In this work, a systematic study is conducted of the potentiostatic (constant driving force) kinetics of phase transition in secondary particles of representative intercalation compounds: LiFePO4, LiMn1–xFexPO4, and Li4Ti5O7. Storage kinetics are studied as a function of overpotential, material composition, primary particle size, and temperature. We find that in regimes where phase transformation occurs, the results can be self-consistently explained as nucleation and growth kinetics within the framework of the Johnson–Mehl–Avrami–Kolmogorov model. This implies that despite the common secondary particle topology, the electrochemically driven phase transformations occur by nucleation and growth with little apparent resistance to phase propagation across the grain boundaries. Growth appears to be one-dimensional in nature, consistent with a hybrid growth model in which rapid surface propagation is followed by slower growth into particles.

The purpose of this paper is to study the approximate optimality condition for composite convex optimization problems with a cone-convex system in locally convex spaces, where all functions involved are not necessarily lower semi-continuous. By using the properties of the epigraph of conjugate functions, we introduce a new regularity condition and give its equivalent characterizations. Under this new regularity condition, we derive necessary and sufficient optimality conditions of $$\varepsilon $$ ε -optimal solutions for the composite convex optimization problem. As applications of our results, we derive approximate optimality conditions to cone-convex optimization problems. Our results extend or cover many known results in the literature.

The intermittency of renewable electricity generation has created a pressing global need for low-cost, highly scalable energy storage. Although pumped hydroelectric storage (PHS) and underground compressed air energy storage (CAES) have the lowest costs today (∼US$100/kWh installed cost), each faces geographical and environmental constraints that may limit further deployment. Here, we demonstrate an ambient-temperature aqueous rechargeable flow battery that uses low-cost polysulfide anolytes in conjunction with lithium or sodium counter-ions, and an air- or oxygen-breathing cathode. The solution energy density, at 30–145 Wh/L depending on concentration and sulfur speciation range, exceeds current solution-based flow batteries, and the cost of active materials per stored energy is exceptionally low, ∼US$1/kWh when using sodium polysulfide. The projected storage economics parallel those for PHS and CAES but can be realized at higher energy density and with minimal locational constraints.

On-machine measurement is a high-efficient measure method in NC machining, and there are pre-travel errors during measurement. What is more, these errors tend to present anisotropy, and affect the measurement accuracy. This paper aimed at measuring the anisotropy of probe’s pre-travel error. First, the standard ball is measured by changing the probe angle with the same machine tool moving direction, and the pre-travel errors with different probe angles under the same machine tool errors are obtained. Then, the machine tool backlash errors are measured and compensated, and the pre-travel errors with different probe angle are obtained. Finally, the mathematical model of pre-travel error is established. The method proposed in this paper can be used to determine probe’s pre-travel error with anisotropy.

The friction and wear properties of nitrile rubber (NBR) against 316L stainless steel pairs were investigated by using a sphere-on-disc test device. The influence of Al2O3particle sizes and the normal load on the tribological behaviors of the pairs were primarily evaluated. The damage behaviors of worn surfaces were analyzed using a scanning electric microscopy (SEM) and a surface profilometer. The results show that the friction coefficient decreased because of particles coming into contact pairs, while particles also play an important role in increasing the wear loss of stainless steel with many furrows on the steel ball surface due to the ploughing effect of hard particles. Large-sized particles could accelerate the wear of rubber, and the micro-cutting scratches of the stainless steel induced by the Al2O3particles embedded in the rubber matrix. However, as the particle’s size decreased, the wear loss of the rubber was gradually mitigated. It is obvious that the normal load affected the wear of the rubber to a larger extent than the stainless steel. Moreover, with large particles, the wear loss of rubber increased sharply with increasing the normal load. In addition, the NBR/stainless steel tribo-pairs presented different wear mechanisms, under different conditions, such as having no particles or varied particle sizes.

Fire safety is one of the most important performances index to evaluate building structures. The property of building members after exposure to fire involved with the safety of buildings after fire, and it will be necessary to estimate the post-fire residual strength of the structure in order to decide the appropriate strategy for repair. This paper summarizes the research progress of concrete-filled steel tubular (CFST) columns. Basic mechanical properties of conventional CFST columns after exposure to fire, CFST columns after the whole fire exposure process under sustained axial load, and CFST columns with special forms after exposure to fire are discussed.

This paper presents a review of research progress in fire performance of concrete-filled steel tubular (CFST) columns. Experimental results of CFST columns in fire are reviewed with influence parameters, such as heights, cross-sectional dimension, section types, concrete types, concrete strengths, load ratio, load eccentricity, fire exposed sides and so on. Some conclusions of CFST columns under fire conditions are summarized. Deficiencies in the fire performance experiments of CFST columns are identified, which provide the focus for future research in the field.

It is becoming a development direction to study green forming process in mechanical. The processing technology of machining deep hole in relative thin sheet is a kind of green mechanical processing technology in this paper. The process uses the friction between driller and workpiece and plasticity of workpiece to form hole. The new technological process not only saves material, but also saves man-hours, and the workpiece has a good piece of assembly. In this paper, the forming process of deep hole on thin sheet was simulated, and some effect factors of forming hole were studied, such as the stress, temperature and shape of forming area, etc. The forming simulation is proved to be feasible by the test in this paper. The study results are useful to improve the machining parameters, and laid a foundation for further research on forming deep holes process on thin sheet metal by friction heat.

To improve lubrication effect and seal performance, complicated geometrical hydrodynamic grooves or patterns are often processed on end faces of liquid lubricated mechanical seals. These structures can lead to difficulties in precisely estimating the seal performance. In this study, an efficient adaptive finite element method (FEM) algorithm with mass conservation was presented, in which a streamline upwind/Petrov-Galerkin (SUPG) weighted residual FEM and a fast iteration algorithm were applied to solve the lubrication equations (Reynolds equation). A mesh adaptation technique was utilized to refine the computation domain based on a residual posterior error estimator. Validation, applicability, and efficiency were verified by comparison among different algorithms and by case studies on seals’ faces with different groove structures. The study investigated the influence of the order of shape function and the mesh number on the leakage balance. Mesh refinement occurred mainly in cavitation zones when cavitation happened, otherwise it occurred in regions with a high pressure gradient. Numerical experiments verified that the proposed algorithm is a fast, effective, and accurate method to simulate lubrication problems in the engineering field apart from end face seals.

A simple and clean way of extraction of natural essence from green tea leaf by supercritical CO2 was developed. The optimum extraction conditions to produce the high-quailty natural essence were found: loading about 100g/L, operating at 5000 psi and 50 °C, and separation kettle temperature 75 °C, static extraction three times with 40 min every time, the yield of natural essence was 0.5%. The product was analyzed by gas chromatography-mass spectrometry (GC-MS) show that dimethylsulfide was the characteristic aroma components of the natural essence with more than 50 kinds of alcohols, ketones, aldehydes, ethers and esters etc.. There were only little other biochemical composition of raw material and 0.4% caffeine in the product detected by high-performance liquid chromatography (HPLC), and the biochemical composition in the raw material were almost no loss before and after extracted by supercritical CO2, it indicated that the specificity of the method for extraction tea natural essence is very strong, and propitious to improve the secondary utilization of the tea raw materials.

The fire protection method of steel space truss structures was researched. Fire protection methods of steel structures were listed. For steel space truss structures, the advantages and disadvantages of fire protection methods were introduced. The screen method was suitable for fire protection of steel space truss structures. One project of fire protection of steel space truss structure was shown as an example. The process of screen method was provided for fire protection of steel space truss structures. According to this project, the technology of fire protection of steel space truss structures was enriched. The research results could help to deal with fire protection of steel space truss structures.

Shear strength and stiffness of fire-damaged reinforced concrete (RC) beams were researched. The nonlinear finite element method (FEM) was developed to simulate shear strength of fire-damaged RC beams. Considering mechanical properties deterioration of concrete and steel reinforcing bar, the parameters of fire-damaged RC beams, including fire exposure time, shear span to depth ratios, concrete strength, diameters of stirrups and spacing of stirrups, were analyzed. Based on numerical analysis, the change of shear strength and stiffness of fire-damaged RC beams were identified. The results showed that shear strength and stiffness of fire-damaged RC beams changed under different parameters. With increase of fire exposure time or increase of shear span to depth ratio or decrease of concrete strength, shear strength and stiffness of fire-damaged RC beams descended obviously. With decrease of diameters of stirrups or increase of spacing of stirrups, shear strength of fire-damaged RC beams descended gradually, but stiffness of fire-damaged RC beams had little change.

The carbon-encapsulated superparamagnetic colloidal nanoparticles (SCNps) were rigidized into soft solids by embedding the SCNps into polyacrylamide hydrogel matrixes under the induction of an external magnetic field. Stabilized by the balance of attractive (magnetic) and repulsive (electrostatic) forces, the SCNps form one-dimension photonic crystal structures along the direction of the external magnetic field and further the structures are frozen into the solidified polymer matrix. The polymer matrix embedded one-dimension photonic crystal structures can strongly diffract visible light and present brilliant color in the light. This novel and soft solid polymer matrix that could be shaped and sliced not only paves a new avenue for develop novel magnetic-responsive photonic crystal materials and devices, but also provides a method to observe the magnetic-induced self-assembly structures of the SCNps in media such as polyacrylamide hydrogel matrixs as a result of the ordered structures frozen into the polyacrylamide hydrogel matrixs. So we can reveal the relationship between their structure and color, and furthermore permit a systematic exploration on magnetically induced self-assembling dynamics, colloidal crystallography which have important significance in the large-scale industrial production in the future.

Heavy metal leaching limits activated carbon from sewage sludge (referred as ACS) to be used for wastewater treatment. Cr and Cd leaching from ACS exceed the permitted values. The leaching content of Cr and Cd decrease much with depositing ACS with chitosan (CS),below the permitted values. This is mainly due to the bind of Cr and Cd with the much group –NH2 of CS. The effects of initial dye concentration, pH and contact time had been studied. The dye adsorbed can act as a supple complexion agent with increasing initial dye concentration, increase the affinity for Cr and Cd. For Cd, the amount leaching of CS/ACS or ACS remains content with pH.The amount leaching of Cr decreases when the pH from 1 to 5 and then increases above the pH of 6.0. The contact time has no important influence on the leaching contents of Cr or Cd.

The assessment method of fire-damaged concrete bridge with prestressed hollow core plate girders was presented in this paper. The historical sketch of assessment of fire-damaged concrete structures was briefly introduced. One fire-damaged concrete bridge with prestressed hollow core plate girders was shown as an example. The process of assessment of fire-damaged concrete bridge with prestressed hollow core plate girders was provided. According to the assessment results, methods of repair and strengthening were presented for different fire-damaged level of prestressed hollow core plate girders. The research results could help expand use of fire-damaged assessment and repair of prestressed concrete bridges.

In order to research the calculation method of shear capacity for fire-damaged reinforced concrete (RC) beams, the reason of drop of shear capacity was analyzed from material properties and transfer mechanisms of RC beams after fire. Formulas of shear capacity were suggested for fire-damaged RC beams. Based on test analysis, the values of reduction factors of shear capacity were proposed under concentrated load. The results show that suggested calculation method is capable of predicting shear capacity of fire-damaged RC beams exactly. The values of reduction factors of shear capacity need further experiments research.