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Selection rules are of vital importance in determining the basic optical properties of atoms, molecules and semiconductors. They provide general insights into the symmetry of the system and the nature of relevant electronic states. A two-dimensional electron gas in a magnetic field is a model system where optical transitions between Landau levels (LLs) are described by simple selection rules associated with the LL index N. Here we examine the inter-LL optical transitions of high-quality bilayer graphene by photocurrent spectroscopy measurement. We observed valley-dependent optical transitions that violate the conventional selection rules Δ|N| = ± 1. Moreover, we can tune the relative oscillator strength by tuning the bilayer graphene bandgap. Our findings provide insights into the interplay between magnetic field, band structure and many-body interactions in tunable semiconductor systems, and the experimental technique can be generalized to study symmetry-broken states and low energy magneto-optical properties of other nano and quantum materials., Optical transitions between Landau levels (LL) in solids are described by selection rules associated with the LL index. Here, the authors perform photocurrent spectroscopy measurements on high-quality bilayer graphene to investigate the interband LL transitions, and observe valley-dependent optical transitions obeying unusual selection rules.

Layer-stacking domain walls in bilayer graphene are emerging as a fascinating one-dimensional system that features stacking solitons structurally and quantum valley Hall boundary states electronically. The interactions between electrons in the 2D graphene domains and the one-dimensional domain-wall solitons can lead to further new quantum phenomena. Domain-wall solitons of varied local structures exist along different crystallographic orientations, which can exhibit distinct electrical, mechanical and optical properties. Here we report soliton-dependent 2D graphene plasmon reflection at different 1D domain-wall solitons in bilayer graphene using near-field infrared nanoscopy. We observe various domain-wall structures in mechanically exfoliated graphene bilayers, including network-forming triangular lattices, individual straight or bent lines, and even closed circles. The near-field infrared contrast of domain-wall solitons arises from plasmon reflection at domain walls, and exhibits markedly different behaviours at the tensile- and shear-type domain-wall solitons. In addition, the plasmon reflection at domain walls exhibits a peculiar dependence on electrostatic gating. Our study demonstrates the unusual and tunable coupling between 2D graphene plasmons and domain-wall solitons.

Defects play a key role in determining the properties and technological applications of nanoscale materials and, because they tend to be highly localized, characterizing them at the single-defect level is of particular importance. Scanning tunnelling microscopy has long been used to image the electronic structure of individual point defects in conductors, semiconductors and ultrathin films, but such single-defect electronic characterization remains an elusive goal for intrinsic bulk insulators. Here, we show that individual native defects in an intrinsic bulk hexagonal boron nitride insulator can be characterized and manipulated using a scanning tunnelling microscope. This would typically be impossible due to the lack of a conducting drain path for electrical current. We overcome this problem by using a graphene/boron nitride heterostructure, which exploits the atomically thin nature of graphene to allow the visualization of defect phenomena in the underlying bulk boron nitride. We observe three different defect structures that we attribute to defects within the bulk insulating boron nitride. Using scanning tunnelling spectroscopy we obtain charge and energy-level information for these boron nitride defect structures. We also show that it is possible to manipulate the defects through voltage pulses applied to the scanning tunnelling microscope tip.

Forming limit curve (FLC) has been applied for evaluating the formability of sheet metal in a standardized way. Various experimental procedures and theoretical models were introduced in the past decades. However, bunches of tests required in the experimental determination of FLC make the procedures more burdensome. In the present study, a combination of experiment and simulation study was conducted with AA5182-O in terms of localized necking and fracture. In the proposed methodology, three experimental procedures, uniaxial tensile, deep drawing with round cup, and dome stretching, were performed and analyzed by using the finite element (FE) simulations. The feasibility of FE models were preliminarily examined by the experimental results. The progression-dependent criterion was developed to determine the process of localized necking to fracture. In the criterion, evolutions of principal strains and their derivatives were calculated and calibrated by validated FE models. The limiting strains obtained from the proposed method showed a good agreement with FLCs obtained using other methods.

This Intense pulsed light (IPL) is skin therapy medical device to remove infection and lesion. The market size of IPL has increased because of increasing device users such as doctors, nurses, engineers, patients. Thus, the number of IPL approvals by Ministry of Food and Drug Safety (MFDS) has increased. However, since there are no standard and guideline for evaluation of IPL performance and safety, it is need to develop the evaluation method of IPL performance and safety for petitioners and examiners who are having difficulties in approval and review. In this study, the criteria and methods for scientific evaluation of safety and performance of IPL are proposed to support approval and review, and it is expected to enhance the international competitiveness of domestic medical device industry and patient safety. To develop the evaluation methods of IPL, first, the types and information of IPL have been collected and analyzed, and relative international and domestic standard and FDA guidance have been studied. Second, drawn test items, criteria and methods were verified at medical device testing institute. Finally, the guideline for evaluation of IPL performance and safety was reviewed through a consultative body composed of academic, industrial, institute, and government experts.

Pairing up electrons and holes in bilayer graphene Excitons—bound pairs of electron and holes in solids—can be harnessed for optoelectronic applications. Being able to tune the exciton energy would bring functional flexibility to such devices. Although tunable excitons have been predicted to form in bilayer graphene, observing them experimentally has been difficult. Ju et al. used high-quality bilayer graphene samples sandwiched between layers of hexagonal boron nitride to observe excitons in this material. Exciton energy was tuned across a large range by controlling the gate voltages. Science , this issue p. 907

Electrically controlling resonant energy transfer of optical emitters provides a novel mechanism to switch nanoscale light sources on and off individually for optoelectronic applications. Graphene's optical transitions are tunable through electrostatic gating over a broad wavelength spectrum, making it possible to modulate energy transfer from a variety of nanoemitters to graphene at room temperature. We demonstrate photoluminescence switching of individual colloidal quantum dots by electrically tuning their energy transfer to graphene. The gate dependence of energy transfer modulation confirms that the transition occurs when the Fermi level is shifted over half the emitter's excitation energy. The modulation magnitude decreases rapidly with increasing emitter-graphene distance (d), following the 1/d(4) rate trend unique to the energy transfer process to two-dimensional materials.

We investigate the ultrafast terahertz response of electrostatically gated graphene upon optical excitation. We observe that the photoinduced terahertz absorption increases in charge neutral graphene but decreases in highly doped graphene. We show that this transition from semiconductor-like to metal-like response is unique for zero bandgap materials such as graphene. In charge neutral graphene photoexcited hot carriers effectively increase electron and hole densities and increase the conductivity. In highly doped graphene, however, photoexcitation does not change net conducting carrier concentration. Instead, it mainly increases electron scattering rate and reduce the conductivity.

According to the characteristics of Wet Flue Gas Desulphurization (FGD), this paper brings forward the automatic control requirements and the control methods. The automatic control system is composed of a Programmable Logic Controller (PLC) and an industrial control computer (PC). The automatic control system can monitor the operating parameters of FGD system automatically and conduct automatic control and adjustment to FGD system. The PLC is responsible for the data collection and automatic control, while the PC is responsible for the surveillance of FGD system operation and the data processing through mutual communications between PC and PLC, which realizes the communication between human and machine and ensures the safe, stable and economic operation of the FGD system.

Ureteric stenting is an effective drainage method in patients with acute urinary tract infection caused by ureteral calculi; however, the optimal ureteral stent indwelling time has not been clearly defined. The aim of this study was to evaluate the effect of ureteric stent indwelling time on the treatment of acute infection secondary to urinary tract calculi. A total of 142 patients with acute infection caused by urinary tract calculi were identified retrospectively from January 2011 to August 2015 at our institution. 63 patients were with ureteric stenting for 7 days (A group) and 79 patients with ureteric stenting for more than 7 days (B group). The patient characteristics of two groups were analyzed and the clinical data before and after stenting were compared. The postoperative complication outcomes were collected and analyzed. Effective drainage obtained from ureteral stenting clearly abated the infection after stenting for 7 days; WBC count, WBCs in urine, and positive rate of urine culture were significantly decreased compared with the condition of immediate stenting. Both groups showed similar stone clearance rates (96.8% vs. 96.2%, p = 0.841), and there was no significant difference in the rate of postoperative complications, especially related to urinary tract infection (6.3% vs. 6.3%, p = 1.000). It is safe and effective for patients with acute urinary tract infection secondary to urinary tract calculi to be treated by ureteroscopic lithotripsy after stenting for one week. Prolonging the stenting period achieves no added benefit for patients.

With our concern about food safety issues, many areas have adopted the food traceability system in management and monitoring the entire chain of food production, processing and marketing. There are still many issues to the existing food traceability system of China such as inconsistent traceability information flow, the non-standard content and the difficulty of sharing and exchanging data. This paper studies and designs beef product traceability system by the introduction of the Internet of things technologies and combining with the technology of RFID and EPC standard. The beef product traceability system that has important theoretical significance and practical value can provide consumers with beef product information query and facilitate the logistics responsibility traceability for managers.

With the widespread use of information systems, traditional manual audit approach cannot adapt to the quick development of information technologies. It has drawbacks of high cost, inefficiency, big risk, poor quality, etc. Computer-assisted audit and its applications are studied in this paper. Firstly, comparative analysis between traditional manual audit and computer-assisted audit is conducted. Then the flow of data-oriented computer-assisted audit is presented and the implementation steps are detailed. Finally, the applications of computer-assisted audit are discussed in four practical audit cases of information systems, i.e. hospital information system, electrical police management system, local taxation management information system and medical insurance fund management information system. And the corresponding audit results are given. The practical audit cases show that computer-assisted audit can expand the audit scope and perform deeper data analysis, thus cutting down the cost and risk of audit while improving efficiency and quality of audit. Therefore, it can effectively help auditors to perform information systems audit.

The unique electronic structure of graphene leads to several distinctive optical properties. In this brief review, we outline the current understanding of two general aspects of optical response of graphene: optical absorption and light emission. We show that optical absorption in graphene is dominated by intraband transitions at low photon energies (in the far-infrared spectral range) and by interband transitions at higher energies (from mid-infrared to ultraviolet). We discuss how the intraband and interband transitions in graphene can be modified through electrostatic gating. We describe plasmonic resonances arising from the free-carrier (intraband) response and excitonic effects that are manifested in the interband absorption. Light emission, the reverse process of absorption, is weak in graphene due to the absence of a band gap. We show that photoluminescence from hot electrons can, however, become observable either through femtosecond laser excitation or strong electrostatic gating.

People in modern societies spend the vast majority of their time in indoor environments, including homes, workplaces, schools, and public spaces. Hence, indoor environmental quality has a significant impact on public health and well-being. Exposure or sensitization to indoor pollutants, including cigarette smoke (Hersoug et al. 2010), air pollution (Trupin et al. 2010), and allergens (Dottorini et al. 2007), is an important risk factor for asthma morbidity. Asthma, a common chronic respiratory disease, has been a growing international issue because its prevalence has been expanding in adults and children. The burden of this disease on governmental healthcare systems, patients and their families is increasing worldwide. It is estimated that there are approximately 300 million asthma patients worldwide and that 15 million disability-adjusted life years are lost annually by those afflicted with asthma (Fukutomi et al. 2010). Asthma usually arises from an interaction between host and environmental factors. A rapid increase in asthma in recent years cannot be ascribed to changes in genetic factors, but rather, to changes in environmental factors. In addition to increased indoor air contaminant exposures, several social factors that may contribute to developing asthma morbidity have been studied; among factors that have been given widespread attention are geographical variations, socioeconomic status (SES), and ethnicity.

In order to solve the electromagnetic heaters' problems of high switching losses and resonant frequency drifting in harsh industrial environments, in this paper, we introduce the soft-switching technology to make the IGBT work on the condition of zero-current turning on and zero-voltage turning off to reduce switching losses, and the IGBT drivers auto adjust the driving frequency to achieve frequency synchronization and adapt the drifting of resonant frequency, in this way, the electromagnetic heaters' adaptability and thermal efficiency can be improved.

Plasmons describe collective oscillations of electrons. They have a fundamental role in the dynamic responses of electron systems and form the basis of research into optical metamaterials. Plasmons of two-dimensional massless electrons, as present in graphene, show unusual behaviour that enables new tunable plasmonic metamaterials and, potentially, optoelectronic applications in the terahertz frequency range. Here we explore plasmon excitations in engineered graphene micro-ribbon arrays. We demonstrate that graphene plasmon resonances can be tuned over a broad terahertz frequency range by changing micro-ribbon width and in situ electrostatic doping. The ribbon width and carrier doping dependences of graphene plasmon frequency demonstrate power-law behaviour characteristic of two-dimensional massless Dirac electrons. The plasmon resonances have remarkably large oscillator strengths, resulting in prominent room-temperature optical absorption peaks. In comparison, plasmon absorption in a conventional two-dimensional electron gas was observed only at 4.2 K (refs 13, 14). The results represent a first look at light-plasmon coupling in graphene and point to potential graphene-based terahertz metamaterials.

Wireless Sensor Networks (WSNs) are widely applied to monitor environments such as military surveillance and reconnaissance. However, individual sensor nodes are vulnerable to some types of attacks because they are usually deployed in open and unprotected environments. Once sensor nodes are compromised, malicious nodes can send erroneous data to the base station, and possibly mislead monitoring results and influence the whole networks' effectiveness. We need to find new mechanisms to protect the wireless networks from attacks. In this paper we develop a scheme for malicious node detection based on weighted-trust evaluation. A weight value is assigned to each sensor node initially. It updates every cycle if the node sends different report from the others. A malicious node will be detected when its weight value is lower than a threshold value. The simulation results show that our approach is more effective in detecting malicious nodes with lower misdetection ratio compared with existing schemes.

Graphene, the single-atom-thick form of carbon, holds promise for many applications, notably in electronics where it can complement or be integrated with silicon-based devices. Intense efforts have been devoted to develop a key enabling device, a broadband, fast optical modulator with a small device footprint. Now Liu et al. demonstrate an exciting new possibility for graphene in the area of on-chip optical communication: a graphene-based optical modulator integrated with a silicon chip. This new device relies on the electrical tuning of the Fermi level of the graphene sheet, and achieves modulation of guided light at frequencies over 1 gigahertz, together with a broad operating spectrum. At just 25 square micrometres in area, it is one of the smallest of its type. Integrated optical modulators with high modulation speed, small footprint and large optical bandwidth are poised to be the enabling devices for on-chip optical interconnects1,2. Semiconductor modulators have therefore been heavily researched over the past few years. However, the device footprint of silicon-based modulators is of the order of millimetres, owing to its weak electro-optical properties3. Germanium and compound semiconductors, on the other hand, face the major challenge of integration with existing silicon electronics and photonics platforms4,5,6. Integrating silicon modulators with high-quality-factor optical resonators increases the modulation strength, but these devices suffer from intrinsic narrow bandwidth and require sophisticated optical design; they also have stringent fabrication requirements and limited temperature tolerances7. Finding a complementary metal-oxide-semiconductor (CMOS)-compatible material with adequate modulation speed and strength has therefore become a task of not only scientific interest, but also industrial importance. Here we experimentally demonstrate a broadband, high-speed, waveguide-integrated electroabsorption modulator based on monolayer graphene. By electrically tuning the Fermi level of the graphene sheet, we demonstrate modulation of the guided light at frequencies over 1 GHz, together with a broad operation spectrum that ranges from 1.35 to 1.6 µm under ambient conditions. The high modulation efficiency of graphene results in an active device area of merely 25 µm2, which is among the smallest to date. This graphene-based optical modulation mechanism, with combined advantages of compact footprint, low operation voltage and ultrafast modulation speed across a broad range of wavelengths, can enable novel architectures for on-chip optical communications.

Background and Aims This study is concerned with the expressions of growth-associated protein-43 (GAP-43) mRNA and protein in the anterior horn of the spinal cord after brachial plexus injury. Methods Animals were killed 1, 7, 14 days after injury and were divided into three injury groups: group 1, right C 7 ventral motor root avulsion; group 2, right C 7 ventral motor root avulsion and cut right C 5 -T 1 dorsal sensitive roots; and group 3, right C 7 ventral motor root avulsion plus right hemisection between C 5 and C 6 segment of the spinal cord. The combined behavioral scores (CBS) 1, 7 and 14 days after surgery were used in behavioral testing. Expressions of both GAP-43 mRNA and protein were analyzed using QRT-PCR and immunohistochemistry 14 days after surgery. Results Among the injury groups, rats in group 3 had the highest score and those in group 1, the lowest score. On day 14 after surgery, the expressions of GAP-43 mRNA and protein were evidently up-regulated compared to the control group, with the highest in group 3 and the lowest in group 1, showing significant differences among the three injury groups ( p Conclusions Our study suggests that the expressions of GAP-43 mRNA and protein may be upregulated after brachial plexus injury, and GAP-43 protein is possibly associated with the axon regeneration and function reconstruction.

Wireless sensor nodes are essential elements in wireless sensor networks. There are two important issues which need to be considered in order to build a sensor node: low power consumption and scalability. This paper proposes and presents a SoC architecture of wireless sensor node based on open source IP blocks such as OpenRISC 1200 microprocessor core and Wishbone Interconnect Matrix bus core. This hardware architecture is then verified in Altera Quartus II, and the power consumption and scalability of the hardware platform are assessed. At last, the whole system of the wireless sensor node is integrated on Altera DE2-70 FPGA board and its sensing, computation and wireless communication capabilities are verified.

This study shows the expression pattern of calcitonin gene-related peptide (CGRP) in the anterior and posterior horns of the spinal cord after brachial plexus injury. The animals were divided into three injury groups: group 1, right C(7) anterior root avulsion; group 2, right C(7) anterior root avulsion and cut right C(5)-T(1) posterior roots; and group 3, right C(7) anterior root avulsion plus right hemitransection between the C(5) and C(6) segments of the spinal cord. These animals were killed at 1, 3, 7 and 14 days after injury. In the anterior horn of all three injured groups, the expression of CGRP increased progressively from day 1 to day 7 (p0.05), peaked on day 7, and then began to decrease slowly. In the posterior horn of all three injured groups, the expression of CGRP decreased gradually from day 1 to day 14 after the operation and was significantly lower on day 14 compared to day 1. At each time point (days 1, 3, 7 and 14), the expression of CGRP was the highest in group 1 and the lowest in group 2, with significant differences among the three groups. The CGRP in the anterior horn of the spinal cord was derived from the cell bodies of motor neurons and was possibly involved in repair mechanisms and regeneration after nerve injury. However, the CGRP in the posterior horn was mainly derived from the posterior root ganglion and was possibly associated with the conduction of noxious stimulation.

Information cascade is a rational conformity behavior which is a type of evolutionary economizing the mental cost of agents. This paper addressed an experimental evidence of information cascades with six experiments employing 2x2x2 treatments in Tianjin. Results show: information cascades reversed less in the asymmetry setting; professional subjects are not employ Bayes rule more frequently than student subjects, and decision accuracy of professional subjects is not higher than that of student subjects; decision accuracy is independent of the order of decision-making; the consistency between private information of current agent and decision result of first agent in same group plays an important role on her behavior and decision accuracy; The accumulative gain/loss and gender of the agent are independent of her behavior; since the mental cost is discount relative to the decision cost in the loss domain, agents will increase the devotion of the mental.

The fibmdendritic layers in the central nucleus of the IC may provide an impoMt substrate for integration of monaural and binaural inputs. To graphically reconstruct and quantify the. 3-D orientation of these layers, we have studied serial Golgi-Cox impregnated sections in low, mid and high frequency regions of the central nucleus. At each site in each 100 pm-thick section, an argon laser scanning confocal microscope is used to take a series of images at discrete steps along the Z-axis. These images are processed by an algorithm to preserve the closely spaced layered dendrites and eliminate the non-layered processes. Four different gradient filters plus median and low pass filters are used to extract the contours of the layers from each image. After processing, the bit-mapped images are converted to vector lists and the objects that represent layered cells selected interactively. The 2-D orientation of the layered cells in each image is determined by performing a linear regression analysis. To create a 3-D surface model that represents a single layer at that site, the regression lines from each image in the Z-series are connected. The spatial orientation of the resultant surface is calculated with two vector cross products at two opposite comers of each non-planar polygon. The average direction of the layer at that site is represented as the average of the normal vectors for the surface model. All of the 3-D surface models from a single brain are displayed together with the outline of the IC. The results show the central part of the central nucleus has a uniform layering pattern, while the more medial and lateral regions have a greater curvature.

We measured tunable interband and intraband transitions in graphene using infrared spectroscopy. Optical transitions across a broad spectral range in graphene can be controlled by electrical gating.