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Metal nanogaps can confine electromagnetic field into extremely small volumes, exhibiting strong surface plasmon resonance effect. Therefore, metal nanogaps show great prospects in enhancing light–matter interaction. However, it is still challenging to fabricate large-scale (centimeter scale) nanogaps with precise control of gap size at nanoscale, limiting the practical applications of metal nanogaps. In this work, we proposed a facile and economic strategy to fabricate large-scale sub-10 nm Ag nanogaps by the combination of atomic layer deposition (ALD) and mechanical rolling. The plasmonic nanogaps can be formed in the compacted Ag film by the sacrificial Al2O3 deposited via ALD. The size of nanogaps are determined by the twice thickness of Al2O3 with nanometric control. Raman results show that SERS activity depends closely on the nanogap size, and 4 nm Ag nanogaps exhibit the best SERS activity. By combining with other porous metal substrates, various sub-10 nm metal nanogaps can be fabricated over large scale. Therefore, this strategy will have significant implications for the preparation of nanogaps and enhanced spectroscopy.

TianQin is a proposed Chinese space-borne gravitational wave detection mission, which will consist of three earth-orbiting spacecraft in equilateral triangle constellation. Due to the ‘3 months on + 3 months off’ observation scheme, the continuous scientific observation period of TianQin is much shorter than LISA, it is highly preferred that other on-board operations, such as charge management, will not interrupt gravitational wave detection. This paper presents a torsion pendulum system on the ground to investigate the continuous discharge method in detail. It is found that the difference in surface characteristics between the test mass and the surrounding housing is the most critical to the success of continuous discharge method. Consequently, the effect of this difference on the continuous discharge process was evaluated in ground simulation experiments, and based on the research results, we also proposed a more feasible spatial continuous charge management strategy for TianQin.

The increase of neutron flux in pulsed spallation neutron facilities imposes demands on the neutron detector for beam monitoring, including excellent neutron/gamma discrimination, wide dynamic neutron-flux measurement range, wavelength resolution, and long-term stability. In this paper, we developed a ceramic GEM-based (gas electron multiplier) neutron detector with an active area of 100 mm × 100 mm. It adopted a thinner conversion material and the stopping layer to lower the detection efficiency so as to extend the dynamic measurement range of the detector. The detection efficiency of this detector was investigated by the Monte Carlo (MC) tool FLUKA, showing that the low efficiency around 0.01% for 1 Åneutrons was reached by using a 0.1 μm natB4C converter appended with an aluminum film of 2 μm thickness. Its validation of the wavelength spectra measurement was verified by comparisons with that made with an LND monitor, and it could work at the condition of 7.1 × 109 n/s for 2.5 Åneutrons. In addition, it was demonstrated that this detector was able to measure the beam profile with a position resolution of better than 2.1 ± 0.1 mm. The results of simulations and experiments show that this ceramic-GEM neutron detector can meet the requirements of the direct measurement of high-flux beam, and it will be a new neutron detector for the beam monitoring at the China spallation neutron source (CSNS).

A local time scale can be generated by steering flywheel clocks with state-of-the-art optical lattice clocks. This paper presents our simulations about the influence of the optical lattice clock’s operational strategies and the flywheel clock’s noise characteristics on the performance of the generated time scale. By post-processing the measured frequency difference between the optical lattice clock Sr1 and the hydrogen maser HM50 at the National Institute of Metrology (NIM), during the modified Julian date (MJD) 59029–59059, a local time scale with 0.68 ns time variation referencing to the TT(BIPM20) is demonstrated.

Short-range tests of the gravitational inverse-square law are very important for finding new interactions. In order to further improve the constraints on the Yukawa-like gravitational force, we propose a new scheme based on the torsion balance, where the speculative Yukawa-like gravitational force between the pendulum and the attractor is substantially increased by increasing the area of the test mass and the source mass. A dual-compensation design is used to realize a null experiment, which can release the accuracy requirement on some geometric parameters. The calculation result shows that, at the 95% confidence level, the new design can establish the strongest bound on the magnitude α of the Yukawa violation at the range of 40–800 μm with the total error of about 2.0 × 10−17 N m, and improve the previous bounds about one order of magnitude at the length scale λ ≈ 300 μm.

We study the hybrid mesons with the exotic quantum numberIGJPC= 0+1−+and investigate their decays into theη η′,a1(1260)π,f1(1285)η,f1(1420)η,K*(892)K¯,K1(1270)K¯, andK1(1400)K¯channels. It is found that the QCD axial anomaly enhances the decay width of theη η′ channel although this mode is strongly suppressed by the small p-wave phase space. Our results support the interpretation of theη1(1855) recently observed by BESIII as thes¯sghybrid meson ofIGJPC= 0+1−+. The QCD axial anomaly ensures theη η′ decay mode to be a characteristic signal of the hybrid nature of theη1(1855).

We propose and analyze an instantaneous frequency measurement system by using optical power monitoring technique with improved resolution. The primary component adopted in the proposal is a dual-polarization quadrature phase shift keying (DP-QPSK) modulator which is used to modulate the microwave signal that has a designed time delay and phase shifting. The generated optical signal is sent to polarization beam splitter (PBS) in DP-QPSK modulator. Owing to the complementary transmission nature of polarization interference introduced by PBS, the frequency information is converted into the optical power and the relationship between the amplitude comparison function (ACF) and microwave frequency to be measured is established. Thus, the frequency of the microwave signal can be easily measured through monitoring the optical powers of the two output ports of the PBS. Furthermore, by adjusting the direct current (DC) biases of the DP-QPSK modulator instead of changing the electrical delay, the measurement range and resolution can be switched. In this paper, the basic principle of the instantaneous frequency measurement system is derived in detail, and simulation has been performed to investigate the resolution, the measurement range, and the influence of imperfection devices. The proposed scheme is wavelength-independent and its measurement range is switchable, which can avoid the laser wavelength drifting problem and thus greatly increasing the system flexibility.

In recent years, gas electron multiplier (GEM) neutron detectors have been developing towards high spatial resolution and high dynamic counting range. We propose a novel concept of an Al stopping layer to enable the detector to achieve sub-millimeter (sub-mm) spatial resolution. The neutron conversion layer is coated with the Al stopping layer to limit the emission angle of ions into the drift region. The short track projection of ions is obtained on the signal readout board, and the detector would get good spatial resolution. The spatial resolutions of the GEM neutron detector with the Al stopping layer are simulated and optimized based on Geant4GarfieldInterface. The spatial resolution of the detector is 0.76 mm and the thermal neutron detection efficiency is about 0.01% when the Al stopping layer is 3.0 μm thick, the drift region is 2 mm thick, the strip pitch is 600 μm, and the digital readout is employed. Thus, the GEM neutron detector with a simple detector structure and a fast readout mode is developed to obtain a high spatial resolution and high dynamic counting range. It could be used for the direct measurement of a high-flux neutron beam, such as Bragg transmission imaging, very small-angle scattering neutron detection and neutron beam diagnostic.

This paper deals with the high-performance temperature control issues of spacecraft thermal vacuum tests. More precisely, the novel model identification and self-tuning PID control method is developed based on neural network. The corresponding controller design details are provided and the experiment results are given for verifying considerable advantages with our proposed control strategy in the end.

In this paper, Fe-10Cr-B alloys with different B content were prepared by the method of liquid phase sintering. Optical microscope (OM), scanning electron microscope (SEM), X-ray diffraction (XRD), Rockwell hardness tester were used to investigate the influence of B element on the structure, phases and macro-hardness of the Fe-10Cr-B alloys. The results show that the hardness of alloys with different B content gradually increases with the increase of B content in the alloy. When the B content is 2.5 wt.%, the hardness of the alloy reaches the maximum value of 61.8HRC. A further increase in the B content will lead to a decrease in the macroscopic hardness of the alloy sample. The alloy with B content of 2.5wt.% is mainly composed of metal matrix and M23 (C, B)6 boron-carbides. The Cr and B elements are mainly enriched in boron-carbides.

Near space has been paid more and more attentionin recent years due to its military application value. However, flow characteristics of some fundamental configurations (e.g., the cavity) in near space have rarely been investigated due to rarefied gas effects, which make the numerical simulation methods based on continuous flow hypothesis lose validity. In this work, the direct simulation Monte Carlo (DSMC), one of the most successful particle simulation methods in treating rarefied gas dynamics, is employed to explore flow characteristics of a hypersonic cavity with sweepback angle in near space by considering a variety of cases, such as the cavity at a wide range of altitudes 20–60 km, the cavity at freestream Mach numbers of 6–20, and the cavity with a sweepback angle of 30°–90°. By analyzing the simulation results, flow characteristics are obtained and meanwhile some interesting phenomena are also found. The primary recirculation region, which occupies the most area of the cavity, causes pressure and temperature stratification due to rotational motion of fluid inside it, whereas the pressure and temperature in the secondary recirculation region, which is a small vortex and locates at the lower left corner of the cavity, change slightly due to low-speed movement of fluid inside it. With the increase of altitude, both the primary and secondary recirculation regions contract greatly and it causes them to separate. A notable finding is that rotation direction of the secondary recirculation region would be reversed at a higher altitude. The overall effect of increasing the Mach number is that the velocity, pressure, and temperature within the cavity increase uniformly. The maximum pressure nearby the trailing edge of the cavity decreases rapidly as the sweepback angle increases, whereas the influence of sweepback angle on velocity distribution and maximum temperature within the cavity is slight.

The traditional Morning jog attendance in colleges and universities is limited to manual supervision by swiping card attendance, which is prone to queuing and sign-in on behalf of others. In addition, the lack of quantitative records of exercise data makes supervision difficult. Location-based attendance systems represented by Dingding time attendance, or simple face recognition attendance systems cannot achieve accurate attendance. The campus happy running system based on face recognition and trajectory tracking innovatively combines face recognition and trajectory tracking, and students achieve accurate attendance certification within the designated “geo-fence”. Practice shows that the system can meet the special needs of colleges and universities for Morning jog attendance and data recording, and it effectively improves the accuracy of identity verification.

Under the traditional mode of classroom teaching, there is a problem that students’ classroom behaviours are inconsistent with their classroom results. In view of the above problems, this paper analyses students’ classroom behaviours through big data, and gives a hidden Markov model. The model can establish the organic relationship between classroom behaviours and students’ results, and adjust the contents that affect classroom behaviours in real time in the process of teaching. The results show that the model is effective, and big data analysis plays an important role in the analysis of curriculum behaviours.

The thermal engineering and energy saving performance of the Trombe wall of a laboratory building in a middle school of Lanzhou region in northwest China were measured and investigated. The results show that during the normal using period in winter 10 years after the building was built, the daily convection heat supply of single group vents is 6.89 kW, the daily average thermal efficiency of the Trombe wall is 18.4 %. In addition, in the process of using the building, it needs to notice that the ventilated channel must be maintained clean and unhindered status, the vents devices must be repaired periodically in order to ensure good opening and closing function, and the vents should be avoided blocking and the ventilation heating mechanism of the Trombe wall should be avoided destroying in later renovation or decoration of the building.

Numerical simulations have been performed to study hydrogen interstitial diffusion and ferroelectric degradation in lead titanate films. The computational method consists of two parts: hydrogen diffusion property calculations using density functional theory (DFT) and ferroelectric property calculations using molecular dynamics (MD) simulations. The hydrogen interstitial diffusion path and the activation energy have been obtained using DFT calculations. With the obtained diffusion properties, the distributions of hydrogen impurities have been calculated using Fick’s second law and used as input to MD simulations, with various diffusion times and hydrogen surface concentrations. It has been found that magnitudes of remnant polarization and coercive electric fields decrease with increasing the diffusion time and the hydrogen surface concentration. The distribution of hydrogen impurities is another critical factor to ferroelectric responses. Compared to a uniform distribution of hydrogen impurities, the nonuniform distribution diminishes the ferroelectric properties more severely. A heavily defective region due to the nonuniform hydrogen distribution reduces the effective film thickness and induces the in-plane ferroelectric domain formations.

Aerosols can have an important impact on human society. Remote sensing method plays an important role in the aerosol retrieval. The aerosol retrieval SARA algorithm isn’t required a lot of prior knowledge and look-up table comparing with the traditional aerosol retrieval algorithms. However, the retrieval results of SARA algorithm are affected by the acquisition time differences and instability of MODIS data and AERONET data. In order to improve SARA algorithm, this paper studies the nonlinear optimization methods to construct the three-parameter model and the five-parameter model. And used the model to optimize the input parameters to improve the accuracy of aerosol retrieval. The correlation of five-parameter optimization results with AERONET sites Beijing and XiangHe is 0.7454 and 0.701 respectively, which is better than that of three-parameter optimization model’s 0.6012, 0.6479, and both are higher than SARA’s 0.3844 and 0.526.

This paper proposes a new method to predict the corona onset voltage for a rod-plane air gap, based on the support vector machine (SVM). Because the SVM is not limited by the size, dimension and nonlinearity of the samples, this method can realize accurate prediction with few training data. Only electric field features are chosen as the input; no geometric parameter is included. Therefore, the experiment data of one kind of electrode can be used to predict the corona onset voltages of other electrodes with different sizes. With the experimental data obtained by ozone detection technology, and experimental data provided by the reference, the efficiency of the proposed method is validated. Accurate predicted results with an average relative less than 3% are obtained with only 6 experimental data.

We investigate the modulation of magnetic anisotropy of thulium iron garnet (TmIG) films by interfaced Bi2Se3 thin films. High quality epitaxial growth of Bi2Se3 films has been achieved by molecular beam epitaxy on TmIG films. By the method of ferromagnetic resonance, we find that the perpendicular magnetic anisotropy (PMA) of TmIG can be greatly strengthened by the adjacent Bi2Se3 layer. Moreover, the competition between topological surface states and thickness dependent bulk states of Bi2Se3 gives rise to the modulation of PMA of the Bi2Se3/TmIG heterostructures. The interfacial interaction can be attributed to the enhanced exchange coupling between Fe3+ ions of TmIG mediated by topological surface electrons of Bi2Se3.

A macroscopic silver nanowire (AgNW) network is grown by solid state ionics method. The ion flow during growth of the AgNW network is controlled by maintaining a current in the order of 10-7 A. Scanning electron microscopy (SEM) analysis reveals that the growth direction of AgNWs in the network is irregular and spread evenly in all directions and the nanowires are 40-160 nm in diameter. The microcosmic mechanism of silver nanostructures grown by the solid state ionics method is established by real time and in situ SEM analysis of the growth process of the AgNW networks. To study the photoelectric properties of the network, a self-supported AgNW network sample (∼1 mm wide and 8 mm long) is irradiated with lasers of different wavelengths of 375, 405, 532, 633, 808, and 1064 nm and 10.6 μm, and changes in the current between the two ends of the sample are recorded. The network displays negative photoconductance effect, and the maximum light responsivity is 43 mA W-1. The network displays light responsivity in the ultraviolet light-to-mid-infrared light region, with response times of tens of milliseconds. These findings indicate that the AgNW network has broad application prospect in ultra-wide spectrum photoelectric detection.

A variable-K trenches silicon-on-insulator (SOI) lateral diffused metal–oxide–semiconductor field-effect transistor (MOSFET) with a double conductive channel is proposed based on the enhancement of low dielectric constant media to electric fields. The device features variable-K dielectric double trenches and a P-pillar between the trenches (VK DT-P LDMOS). The low-K dielectric layer on the surface increases electric field of it. Adding a variable-K material introduces a new electric field peak to the drift region, so as to optimize electric field inside the device. Introduction of the high-concentration vertical P-pillar between the two trenches effectively increases doping concentration of the drift region and maintains charge balance inside it. Thereby, breakdown voltage (BV) of the device is increased. The double conductive channels provide two current paths that significantly reduce specific on-resistance (R on,sp). Simulation results demonstrate that a 17-μm-length device can achieve a BV of 554 V and a low on-resistance of 13.12 mΩ⋅cm2. The R on,sp of VK DT-P LDMOS is reduced by 78.9% compared with the conventional structure.

In order to solve the low utilization rate of spatio-temporal sequence information during non-cooperative target recognition of optical remote sensing images with deep learning method, this paper puts forward a new method for offshore non-cooperative target recognition and tracing based on spatio-temporal reasoning. In the first stage, this method uses YOLOv3 model through deep learning to recognize characteristics of large batch of offshore non-cooperative target images, and finish preliminary screening of suspicious target; in the second stage, it uses time weight function and Markov model to process and analyze temporal and spatial sequence information respectively during continuous tracing of the target and get the probability distribution of certain specific target in the two dimensions; in the third stage, it uses D-S evidence theory to process probability inforamtion in temporal and spatial dimensions and get target probability with higher reliability through fusion reasoning. The experimental verification shows the comprehensive recognition precision in the first stage is over 92%; subsequently the secondary recognition precision of the target can be improved for 35% through fusion reasoning of time weighted position distribution probability and Markov position transfer probability. Results show the reasoning elements of spatio-temporal sequences obvious improve precision of secondary discovery after the non-cooperative target is lost, and provide new thinking for non-cooperative target tracing with intelligent method.

The traditional intrusion detection system feature model is based on static data mining. Its mining algorithm relies on too many assumptions, which makes it difficult for intrusion detection systems to adapt to dynamic and real-time system detection requirements. Using attenuated sliding window technology, data stream mining technology and fusion technology with intrusion detection system, a data flow clustering algorithm based on attenuated sliding window is designed to improve and optimize the feature pattern extraction method of intrusion detection system to solve the dynamics of intrusion detection system. Through algorithm design, algorithm application and intrusion detection system simulation verification, the feasibility and accuracy of the algorithm and the optimized intrusion detection system are proved.

Inspired by the recent measurement of the process , we calculate the mass spectrum of the meson with the GI model. For the excited vector strangeonium states and , we investigate the electronic decay width with the Van Royen-Weisskopf formula, and the partial widths of the , , and decay modes with the extended quark-pair creation model. We find that the electronic decay width of the -wave vector strangeonium is about times larger than of the -wave vector strangeonium. Around 2232 MeV, the partial decay width of the mode can be up to several MeV for , while the partial decay width of is keV. If the threshold enhancement reported by the BESIII collaboration arises from the strangeonium meson, this state is very likely the state. We also note that the and partial decay widths of the states and are several MeV, which is sufficient to be observed in future experiments.

Fast and sensitive detection of terahertz radiation is notoriously difficult, especially the detection at the ambient condition. Here, we fabricated bolometric terahertz photodetectors based on suspended carbon nanotube (CNT) fibers. Because the CNT fibers exhibit a very small heat dissipation area, the heat transport from the CNT fibers to the air is negligible. It ensures the devices can work well at the ambient condition. Additionally, the CNT fibers demonstrate a high responsivity up to 0.54 A W−1 and a short response time of 200 μs. This implies a performance that is competitive among the terahertz photodetectors based on CNT.

The developed coating performance meets the corresponding technical specification by using modified epoxy resin and E51 epoxy resin as resin system to optimize the system viscosity and flexibility, adding reactive diluents owning good flexibility, using modified alicyclic amine curing agent with good flexible performance and corrosion resistance, optimizing assistant system concluding defoaming agent, levelling agents and so on. Application adaptability, concluding viscosity, thixotropy, sag resistance and pot life, were also studied under different temperatures, considering that these parameter are important to spraying process. The dry film thickness can be adjusted between 60-150 μ m by modulating spraying application parameters, meanwhile, the flat smooth film meets internal drag reducing coating technical parameters requests. The product were successfully applied in China key projects. According to field pilot test, application attention items were also discussed.

In the framework of the one-boson-exchange model, we have performed an extensive study of the possible B*, B**, D*, D** molecular states with various quantum numbers after considering the S-wave and D-wave mixing. We also discuss the possible experimental research of these interesting states.

Herein, we propose a new strategy to fabricate gold (Au) micro/nanostructure arrays by photocatalytic solid-state electrochemical reaction between superionic conductor RbAg4I5 and Au films. The Au and RbAg4I5 films were successively deposited on a clean quartz substrate by vacuum thermal deposition method. A copper microgrid possessing periodic holes 100 μm in diameter was put above the RbAg4I5 film as a mask plate, whereupon irradiation from a 405 nm wavelength laser was used to diffuse gold ions (Au+ ions) into vacant silver sites of RbAg4I5 and transfer Au+ through ion passageways in the RbAg4I5 film. When the laser was turned off, the Au+ ions were easily reduced due to low activity compared to the silver (Ag+) ions. After multiple on/off cycles of the 405 nm laser, the irradiated area of uniform Au film exhibited a periodic structural unit array whose period was the same as that of the mask plate hole array. Atomic force microscope and scanning electron microscope images revealed that a self-assembled needle-like nanostructure array grew perpendicular to the substrate surface inside each circle's structural unit. The height of the grown nanostructure array increased with laser power density. Raman enhancement of the gold nanostructure array as substrate was detected using Rhodamine 6G (R6G) ethanol solutions as probe molecules. The enhancement effect increased with the height of the grown nanostructure array, and could increase by two orders of magnitude greater than that of unirradiated Au film. This strategy offers a new method for the micro/nanostructure processing of gold and provides microscale-array-mediated surface-enhancement Raman-scattering (SERS) substrates comprising Au nanostructures for application in high-sensitivity spectrum analysis.

In recently years, the establishment of university campus has been on a rise, but the campus ecology is confronted with unprecedented challenges. Campus waterscape is one of the most important part of campus ecological system. The implementation of ecological design principle has been an important issue of planning programming. Besides, the current situation of campus ecology is worth being focused and studied. The paper has studied and analysed central waterscape of 5 universities in Guangzhou through field investigation. Based on the theory of water ecosystem service and Analytic hierarchy process (AHP), the paper aims to make a comprehensive comment on ecological environment of Guangzhou university town, whose problems are concluded. Corresponding policies are made to establish sustainable waterscape with good ecological environment, beautiful landscape and suitable activity venues, which will achieve the sustainable landscape effect for campus waterscape design.

An oxygen vacancy, known to be detrimental to ferroelectric properties, has been investigated numerically for the potential uses to control ferroelectric domains in films using molecular dynamics simulations based on the first-principles effective Hamiltonian. As an electron donor, an oxygen vacancy generates inhomogeneous electrostatic and displacement fields which impose preferred polarization directions near the oxygen vacancy. When the oxygen vacancies are placed at the top and bottom interfaces, the out-of-plane polarizations are locally developed near the interfaces in the directions away from the interfaces. These polarizations from the interfaces are in opposite directions so that the overall out-of-plane polarization becomes significantly reduced. In the middle of the films, the in-plane domains are formed with containing 90° a 1/a 2 domain walls and the films are polarized along the [1 1 0] direction even when no electric field is applied. With oxygen vacancies placed at the top interface only, the films exhibit asymmetric hysteresis loops, confirming that the oxygen vacancies are one of the possible sources of ferroelectric imprint. It has been qualitatively demonstrated that the domain structures in the imprint films can be turned on and off by controlling an external field along the thickness direction. This study shows qualitatively that the oxygen vacancies can be utilized for tuning ferroelectric domain structures in films.

The efficiency potentials of future generation solar cells such as wide bandgap chalcopyrite, Cu2ZnSnS4 (CZTS), Cu2ZnSn(S,Se)4 (CZTSSe), multi quantum well (MQW) and quantum dot (QD) solar cells are discussed on the basis of external radiative efficiency (ERE), open-circuit voltage loss, fill factor loss, and nonradiative recombination losses. CZTS and CZTSSe solar cells have efficiency potentials of more than 20% owing to the improvement in ERE from about 0.001 to 1%. MQW and QD cells have efficiency potentials of 24.8%, and 25.8% owing to the improvement in ERE from around 0.01 to 0.1%, and 1%, respectively. In this paper, the effects of nonradiative recombination on the properties of future generation solar cells are discussed.

Because the nucleon may be excited and transformed into a virtual $\Delta$ resonance easily, we consider the decuplet contribution to the parity-violating (PV) nucleon-nucleon interaction in the chiral effective field theory. The effective PV nucleon-nucleon potential is derived without introducing any unknown coupling constants.

ZrO2 films were prepared by nitrogen-assisted radio frequency (RF) reactive sputtering on n-type silicon (100). Optical properties and band alignments of ZrO2 films on Si have been investigated by using x-ray photoelectron spectroscopy (XPS) and spectroscopy ellipsometry (SE). The improved film quality was obtained after annealing in N2/O2 ambient with stable interfacial properties. Optical properties were analysed based on the SE fitting results. According to the valence-band spectrum results, the zero-field energy-band alignments for ZrO2/SiO2/Si stacks were also extracted. Our results indicate that the nitrogen-assisted process shows its outstanding ability in the control of interfaces and has potential application in microelectronics.

A two-dimensional double-barrier nanoring under in-plane electric fields is proposed to investigate field-controlled two-electron spectra and entanglements. It has been found that changing the direction of the field can destroy the symmetries of the wavefunctions and has great impact on the spectra. The angle between the barriers, along with the intensity and direction of the field, can be used for controlling the entanglements of both the ground and excited states. The structure-dependent and field-controlled far-infrared spectroscopies are useful in such investigations. It is helpful for manipulating the entanglements of indistinguishable particles in nanostructures.

First-principles calculations have been performed to study the electronic band structure and the magnetic properties for the polymeric compound of Cu(thiazole)(2)Br-2 and M(thiazole)(2)Cl-2 (M = Cu, Fe). The relative stability of the ground state, density of states and electronic band structure were examined. Total energy calculations reveal that the antiferromagnetic phase is a stable ground state for Cu(thiazole)(2)Br-2 and M(thiazole)(2)Cl-2 (M = Cu, Fe). It is noteworthy that we predict the compound Fe(thiazole)(2)Cl-2 is a metallic antiferromagnet and has a half-metallic (HM) ferromagnetic metastable state. But the spin-up and spin-down DOS in the ferromagnetic and anti ferromagnetic phases of the compounds Cu(thiazole)(2)Cl-2 and Cu(thiazole)(2)Br-2 all opened a large bandgap. The spin magnetic moments of Cu(thiazole)(2)Br-2 and M(thiazole)(2)Cl-2 (M = Cu, Fe) are mainly assembled at the copper and iron atoms, with a little contribution from the chlorine, bromine, nitrogen, sulfur, and carbon atoms.

Atomic force microscopy (AFM) has garnered much interest in recent years for its ability to probe the structure, function and cellular nanomechanics inherent to specific biological cells. In particular, we have used AFM to probe the important structure-function relationships of the bacterium Streptococcus mutans. S. mutans is the primary aetiological agent in human dental caries (tooth decay), and is of medical importance due to the virulence properties of these cells in biofilm initiation and formation, leading to increased tolerance to antibiotics. We have used AFM to characterize the unique surface structures of distinct mutants of S. mutans. These mutations are located in specific genes that encode surface proteins, thus using AFM we have resolved characteristic surface features for mutant strains compared to the wild type. Ultimately, our characterization of surface morphology has shown distinct differences in the local properties displayed by various S. mutans strains on the nanoscale, which is imperative for understanding the collective properties of these cells in biofilm formation.

The effects of transverse field and a single defect on the conductance of an achiral carbon nanotube have been investigated. It is found that armchair nanotubes under the transverse field are always metallic, and that field-induced metal–semiconductor (MS) and semiconductor–metal (SM) transitions are shown for zigzag nanotubes. MS transition fields are independent of the defect while SM transition fields are sensitive to the field-defect azimuth, defect type and its strength. Most importantly, the field-defect azimuth is a new freedom and can be used to tailor and control the electronic behaviour. The experimental confirmation of the prediction may be possible.