Polarization-stable single-mode 795†nm grating-coupled surface-emitting laser for quantum sensing.

We demonstrate a polarization-stable and single-mode grating-coupled surface-emitting laser (GCSEL) with high side-mode suppression ratio (SMSR) of ∼40 dB and orthogonal polarization suppression ratio (OPSR) of ∼25 dB around 795 nm. The fabricated devices have low threshold current of ∼4.8 mA and low electrical resistance of 53 Ω at 25 °C. Meanwhile, a low thermal resistance of ∼1 K/mW is achieved, which is comparable with that of the record of ever reported for vertical-cavity surface-emitting lasers (VCSELs). The far-field divergence angle of surface-emitting beam is ∼14.5°x14.7° at an injection current of 12 mA indicating a relatively good beam quality. Our results open what we believe is a new way to produce polarization-stable single-mode surface-emitting lasers with simple fabrication process. While the GCSEL is specifically designed for quantum sensing applications such as atomic clocks, magnetometers, and gyroscope, its performance in terms of low-power consumption, low thermal resistance, good beam qualities, and wafer-level testing are of particular interest for a wide range of applications.

Dynamic phase manipulation of vertical-cavity surface-emitting lasers via on-chip integration of microfluidic channels.

Vertical-cavity surface-emitting lasers (VCSELs) play a key role in the development of the next generation of optoelectronic technologies, thanks to their unique characteristics, such as low-power consumption, circular beam profile, high modulation speed, and large-scale two-dimensional array. Dynamic phase manipulation of VCSELs within a compact system is highly desired for a large variety of applications. In this work, we incorporate the emerging microfluidic technologies into the conventional VCSELs through a monolithic integration approach, enabling dynamic phase control of lasing emissions with low power consumption and low thermal generation. As a proof of concept, a beam steering device is experimentally demonstrated by integrating microfluidic channel on a coherently coupled VCSELs array. Experimental results show that the deflection angles of the laser beam from the chip can be tuned from 0° to 2.41° under the injection of liquids with different refractive index into the microchannel. This work opens an entirely new solution to implement a compact laser system with real-time wavefront controllability. It holds great potentials in various applications, including optical fiber communications, laser printing, optical sensing, directional displays, ultra-compact light detection and ranging (LiDAR).

High responsivity graphene-InGaAs near-infrared photodetector realized by hole trapping and its response saturation mechanism.

Graphene is an ideal material for wide spectrum detector owing to its special band structure, but its low light absorption and fast composite of photogenerated carriers lead to a weak response performance. In this paper, we designed a unique photoconductive graphene-InGaAs photodetector. The built-in electric field was formed between graphene and InGaAs, which can prolong the lifetime of photogenerated carriers and improve the response of devices by confining the holes. Compared with graphene-Si structure, a higher built-in electric field and reach to 0.54 eV is formed. It enables the device to achieve a responsivity of 60 AW-1 and a photoconductive gain of 79.4 at 792 nm. In the 1550 nm communication band, the responsivity of the device is also greater than 10 AW-1 and response speed is less than 2 ms. Meanwhile, the saturation phenomenon of light response was also found in this photoconductive graphene heterojunction detector during the experiment, we have explained the phenomenon by the capacitance theory of the built-in electric field, and the maximum optical responsivity of the detector is calculated theoretically, which is in good agreement with the measurement result.

Graphene-assisted preparation of large-scale single-crystal Ag(111) nanoparticle arrays for surface-enhanced Raman scattering.

Surface plasmon resonance (SPR) of metal nanostructures has broad application prospects in the fields of sensing, energy, catalysis and optics. This paper reports a graphene-assisted method for preparing large-scale single-crystal Ag(111) nanoparticle (NP) arrays based on the ion implantation technique. By surface periodic patterning treatment and annealing of the implanted sample, regularly arranged Ag NPs can be prepared on the sample surface. A new application for graphene is proposed, that is, as a perfect barrier layer to prevent metal atoms from evaporating or diffusing. All the Ag NPs show (111) crystal orientation. Besides, the Ag atoms are covered by graphene immediately when they precipitate from the substrate, which can prevent them from being oxidized. On the basis of this structure, as one of the applications of the metal SPR, we have measured the surface-enhanced Raman scattering effect and found that the G peak of the Raman spectrum of the graphene achieved about 20 times enhancement.

Self-Assembly and Molecular Recognition in Water: Tubular Stacking and Guest-Templated Discrete Assembly of Water-Soluble, Shape-Persistent Macrocycles.

Supramolecular chemistry in aqueous media is an area with great fundamental and practical significance. To examine the role of multiple noncovalent interactions in controlled assembling and binding behavior in water, the self-association of five water-soluble hexakis(m-phenylene ethynylene) (m-PE) macrocycles, along with the molecular recognition behavior of the resultant assemblies, is investigated with UV-vis, fluorescence, CD, and NMR spectroscopy, mass spectrometry, and computational studies. In contrast to their different extents of self-aggregation in organic solvents, all five macrocycles remain aggregated in water at concentrations down to the micromolar (µM) range. CD spectroscopy reveals that 1-F6 and 1-H6, two macrocycles carrying chiral side chains and capable of H-bonded self-association, assemble into tubular stacks. The tubular stacks serve as supramolecular hosts in water, as exemplified by the interaction of macrocycles 1-H6 and 2-H6 and guests G1 through G4, each having a rod-like oligo(p-phenylene ethynylene) (p-PE) segment flanked by two hydrophilic chains. Fluorescence and 1H NMR spectroscopy revealed the formation of kinetically stable, discrete assemblies upon mixing 2-H6 and a guest. The binding stoichiometry, determined with fluorescence, 1H NMR, and ESI-MS, reveals that the discrete assemblies are novel pseudorotaxanes, each containing a pair of identical guest molecules encased by a tubular stack. The two guest molecules define the number of macrocyclic molecules that comprise the host, which curbs the "infinite" stack growth, resulting in a tubular stack with a cylindrical pore tailoring the length of the p-PE segment of the bound guests. Each complex is stabilized by the action of multiple noncovalent forces including aromatic stacking, side-chain H-bonding, and van der Waals interactions. Thus, the interplay of multiple noncovalent forces aligns the molecules of macrocycles 1 and 2 into tubular stacks with cylindrical inner pores that, upon binding rod-like guests, lead to tight, discrete, and well-ordered tubular assemblies that are unprecedented in water.

A Heterogeneous Network Modeling Method Based on Public Goods Game Theory to Explore Cooperative Behavior in VANETs.

Cooperative vehicular networking has been widely studied in recent years. Existing evolution game theoretic approaches to study cooperative behavior in Vehicular Ad hoc Network (VANET) are mainly based on the assumption that VANET is constructed as a homogeneous network. This modeling method only extracts part attributes of vehicles and does not distinguish the differences between strategy and attribute. In this paper, we focus on the heterogeneous network model based on the public goods game theory for VANET. Then we propose a Dynamic Altruism Public Goods Game (DAPGG) model consisting of rational nodes, altruistic nodes, and zealots to more realistically characterize the real VANET. Rational nodes only care about their own benefits, altruistic nodes comprehensively consider the payoffs in the neighborhood, while zealots insist on behaving cooperatively. Finally, we explore the impacts of these attributes on the evolution of cooperation under different network conditions. The simulation results show that only adding altruistic nodes can effectively improve the proportion of cooperators, but it may cause conflicts between individual benefits and neighborhood benefits. Altruistic nodes together with zealots can better improve the proportion of cooperators, even if the network conditions are not suitable for the spread of cooperative behavior.

MultiFuzz: A Coverage-Based Multiparty-Protocol Fuzzer for IoT Publish/Subscribe Protocols.

The publish/subscribe model has gained prominence in the Internet of things (IoT) network, and both Message Queue Telemetry Transport (MQTT) and Constrained Application Protocol (CoAP) support it. However, existing coverage-based fuzzers may miss some paths when fuzzing such publish/subscribe protocols, because they implicitly assume that there are only two parties in a protocol, which is not true now since there are three parties, i.e., the publisher, the subscriber and the broker. In this paper, we propose MultiFuzz, a new coverage-based multiparty-protocol fuzzer. First, it embeds multiple-connection information in a single input. Second, it uses a message mutation algorithm to stimulate protocol state transitions, without the need of protocol specifications. Third, it uses a new desockmulti module to feed the network messages into the program under test. desockmulti is similar to desock (Preeny), a tool widely used by the community, but it is specially designed for fuzzing and is 10x faster. We implement MultiFuzz based on AFL, and use it to fuzz two popular projects Eclipse Mosquitto and libCoAP. We reported discovered problems to the projects. In addition, we compare MultiFuzz with AFL and two state-of-the-art fuzzers, MOPT and AFLNET, and find it discovering more paths and crashes.

[Analysis of beta-globin gene variants in Liuzhou area of Guangxi].

OBJECTIVE: To determine the composition and distribution of beta-thalassemia-associated genotypes in Liuzhou area of Guangxi, China. METHODS: From January to December 2017, 13 847 individuals who came for premarital examination, maternity examination or health check were recruited with informed consent. The subjects were analyzed by reverse dot blotting (RDB) for 17 common beta-thalassemia-associated variants among the Chinese population. Individuals with inconsistent results by blood test, electrophoresis, and RDB were subjected to Sanger sequencing to detect rare variants of the beta globin gene. RESULTS: In total 2098 individuals were found to harbor beta-thalassemia-associated variants, which included 2075 heterozygotes (98.90%), 12 compound heterozygotes (0.57%) and 11 homozygotes (0.52%). CD41-42 (48.43%) and CD17 (31.45%) were the most common variants. Three hundred and thirty eight-individuals were found to also carry heterozygous variants of the alpha globin gene, with the most common types being --SEA/aa, -a3.7/aa, aCSa/aa, -a4.2/aa. Through Sanger sequencing, rare genotypes such as beta-32/betaN, betaCD41-42/betaIVS-II-5 and betaCD30/betaN were detected. CONCLUSION: Liuzhou area has a high incidence of beta-thalassemia, but with a complex variant spectrum and clinical phenotypes different from other regions. Genetic counseling and prenatal diagnosis for the carrier population is crucial for the reduction of the related birth defects. Our result may provide valuable information for the prevention and control of beta-thalassemia in this area.

Ultra-compact electrically controlled beam steering chip based on coherently coupled VCSEL array directly integrated with optical phased array.

Beam steering devices have wide applications in both military and civil fields. The ultimate goal for such devices is to reduce their size, weight, and power consumption. However, the laser source in these devices is spatially separate from the phase shifter, resulting in large size, complex packaging, and low coupling efficiency. To solve these problems, a novel electrically controlled beam steering chip based on coherently coupled vertical cavity surface emitting laser (VCSEL) array directly integrated with liquid crystal optical phased array (LCOPA) is proposed in this paper. Implant-defined in-phase coherently coupled VCSEL arrays (CCVAs) with uniform near-field are designed and fabricated first to act as the coherent laser source for the chip. Then, taking advantage of the CCVA planar structure, the LCOPA is integrated directly on the CCVA by conventional process. The coherent light generated by the in-phase CCVA is uniformly and normally incident into the LCOPA and is electrically steered by the LCOPA. One-dimensional beam steering is achieved by two proof-of-concept integrated chips. The chips based on a 4 × 4 square CCVA and a 16-element hexagonal CCVA offer a field of view of 2.21° and 6.06°, respectively. Independent control of the CCVA and LCOPA guarantees a relatively high wavelength stability and power stability. Theoretical calculations are also performed, which are consistent with the experiments.

HPLC and SFC enantioseparation of (±)-Corey lactone diol: Impact of the amylose tris-(3,5-dimethylphenylcarbamate) coating amount on chiral preparation.

As an important intermediate of prostaglandins and entecavir, optically pure Corey lactone diol (CLD) has great value in the pharmaceutical industry. In this work, the enantioseparation of (±)-CLD was evaluated using high-performance liquid (HPLC) and supercritical fluid chromatography (SFC). In HPLC, the separations of CLD enantiomers on polysaccharide-based chiral stationary phases with both normal phase and polar organic phase were screened. And the conditions for the enantioseparation were optimized in HPLC and SFC, including the selection of mobile phase, temperature, back-pressure, and other conditions. More important, it was found that the chiral resolutions were greatly enhanced by the increase of the coating amount of ADMPC (amylose tris-(3,5-dimethylphenylcarbamate)) under both HPLC and SFC conditions, which can lead to the increase of the productivity and the decrease of the solvent consumption. The preparations of optically pure CLD were evaluated on a semi-preparative (2 × 25 cm) column packed with 30% ADMPC-coated CSP under HPLC and SFC conditions. Preparative performances in terms of kkd are 1.536 kg racemate/kg CSP/day and 1.248 kg racemate/kg CSP/day in HPLC and SFC, respectively.

SPS and DPS: Two New Grid-Based Source Location Privacy Protection Schemes in Wireless Sensor Networks.

Wireless Sensor Networks (WSNs) have been widely deployed to monitor valuable objects. In these applications, the sensor node senses the existence of objects and transmitting data packets to the sink node (SN) in a multi hop fashion. The SN is a powerful node with high performance and is used to collect all the information sensed by the sensor nodes. Due to the open nature of the wireless medium, it is easy for an adversary to trace back along the routing path of the packets and get the location of the source node. Once adversaries have got the source node location, they can capture the monitored targets. Thus, it is important to protect the source node location privacy in WSNs. Many methods have been proposed to deal with this source location privacy protection problem, and most of them provide routing path diversity by using phantom node (PN) which is a fake source node used to entice the adversaries away from the actual source node. But in the existing schemes, the PN is determined by the source node via flooding, which not only consumes a lot of communication overhead, but also shortens the safety period of the source node. In view of the above problems, we propose two new grid-based source location privacy protection schemes in WSNs called grid-based single phantom node source location privacy protection scheme (SPS) and grid-based dual phantom node source location privacy protection scheme (DPS) in this paper. Different from the idea of determining the phantom node by the source node in the existing schemes, we propose to use powerful sink node to help the source node to determine the phantom node candidate set (PNCS), from which the source node randomly selects a phantom node acting as a fake source node. We evaluate our schemes through theoretical analysis and experiments. Experimental results show that compared with other schemes, our proposed schemes are more efficient and achieves higher security, as well as keeping lower total energy consumption. Our proposed schemes can protect the location privacy of the source node even in resource-constrained wireless network environments.

Transfer-free, lithography-free and fast growth of patterned CVD graphene directly on insulators by using sacrificial metal catalyst.

Chemical vapor deposited graphene suffers from two problems: transfer from metal catalysts to insulators, and photoresist induced degradation during patterning. Both result in macroscopic and microscopic damages such as holes, tears, doping, and contamination, translated into property and yield dropping. We attempt to solve the problems simultaneously. A nickel thin film is evaporated on SiO2 as a sacrificial catalyst, on which surface graphene is grown. A polymer (PMMA) support is spin-coated on the graphene. During the Ni wet etching process, the etchant can permeate the polymer, making the etching efficient. The PMMA/graphene layer is fixed on the substrate by controlling the surface morphology of Ni film during the graphene growth. After etching, the graphene naturally adheres to the insulating substrate. By using this method, transfer-free, lithography-free and fast growth of graphene realized. The whole experiment has good repeatability and controllability. Compared with graphene transfer between substrates, here, no mechanical manipulation is required, leading to minimal damage. Due to the presence of Ni, the graphene quality is intrinsically better than catalyst-free growth. The Ni thickness and growth temperature are controlled to limit the number of layers of graphene. The technology can be extended to grow other two-dimensional materials with other catalysts.

An LC-MS/MS method for quantitation of cyanidin-3-O-glucoside in rat plasma: Application to a comparative pharmacokinetic study in normal and streptozotocin-induced diabetic rats.

A sensitive and reliable liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed to determine cyanidin-3-O-glucoside (Cy-3G) in normal and streptozotocin-induced diabetic rat plasma. Chromatographic separation was carried out on a Zorbax SB-C18 (50 × 4.6 mm, 5 µm) column and mass spectrometric analysis was performed using a Thermo Finnigan TSQ Quantum Ultra triple-quadrupole mass spectrometer coupled with an ESI source in the negative ion mode. Selected reaction monitoring mode was applied for quantification using target fragment ions m/z 447.3 → 285.2 for Cy-3G and m/z 463.0 → 300.1 for quercetin-3-O-glucoside (internal standard). The calibration curve was linear over the range 3.00-2700 ng/mL (r2 ≥ 0.99) with the lower limit of quantitation at 3.00 ng/mL. Intra- and inter-day precision was <14.5% and mean accuracy was from -11.5 to 13.6%. Stability testing showed that Cy-3G remained stable during the whole analytical procedure. After validation, the assay was successfully used to support a preclinical pharmacokinetic comparison of Cy-3G between normal and diabetic rats. Results indicated that diabetes mellitus significantly altered the in vivo pharmacokinetic characteristics of Cy-3G after oral administration in rats.

Enforced Tubular Assembly of Electronically Different Hexakis(m-Phenylene Ethynylene) Macrocycles: Persistent Columnar Stacking Driven by Multiple Hydrogen-Bonding Interactions.

Hexakis(m-phenylene ethynylene) (m-PE) macrocycles 1-4, sharing the same hydrogen-bonding side chains but having backbones of different electronic properties, are designed to probe the effectiveness of multiple H-bonding interactions in enforcing columnar assemblies. 1H NMR, absorption, fluorescence, and circular dichroism (CD) spectroscopy indicate that, compared with analogous macrocycles that self-associate based on aromatic stacking which is highly sensitive to the electronic nature of the macrocyclic backbones, macrocycles 1-4 all exhibit strong aggregation down to the micromolar (µM) concentrations in nonpolar solvents. Increasing solvent polarity quickly weakens aggregation. In THF and DMF, the macrocycles exist as free molecules. The observed solvent effects, along with the behavior of 5-F6 that cannot self-associate via H-bonding, confirm that H-bonding plays the dominating role in driving the self-association of 1-4. The backbone electronic nature does not change the self-assembling pattern common to 1-4. Fluorescence and CD spectra confirm that macrocycles 1-4 assemble anisotropically, forming helical stacks in which adjacent molecules undergo relative rotation to place individual benzene residues in the favorable offset fashion. Columnar alignment of 1-4 is confirmed by atomic force microscopy (AFM), which resolves single tubes consisting of stacked macrocycles. In addition, macrocycles with backbones of different electronic properties are found to undergo heteroassociation, forming hybrid nanotubes. This study has demonstrated the generality of enforcing the alignment of shape-persistent macrocycles, which represents an invaluable addition to the small number of known tubular stacks capable of accommodating structurally varied molecular components and provides self-assembling nanotubes with inner pores allowing ready structural and functional modification.

A Novel Physical Layer Assisted Authentication Scheme for Mobile Wireless Sensor Networks.

Physical-layer authentication can address physical layer vulnerabilities and security threats in wireless sensor networks, and has been considered as an effective complementary enhancement to existing upper-layer authentication mechanisms. In this paper, to advance the existing research and improve the authentication performance, we propose a novel physical layer assisted authentication scheme for mobile wireless sensor networks. In our proposed scheme, we explore the reciprocity and spatial uncorrelation of the wireless channel to verify the identities of involved transmitting users and decide whether all data frames are from the same sender. In our proposed scheme, a new method is developed for the legitimate users to compare their received signal strength (RSS) records, which avoids the information from being disclosed to the adversary. Our proposed scheme can detect the spoofing attack even in a high dynamic environment. We evaluate our scheme through experiments under indoor and outdoor environments. Experiment results show that our proposed scheme is more efficient and achieves a higher detection rate as well as keeping a lower false alarm rate.

Immunological enhancement action of endotoxin-free tilapia heat shock protein 70 against Streptococcus iniae.

The immunological effects of heat shock proteins (HSPs) had been found in humans and mice, but scarce data of endotoxin-free Hsp70 were reported in tilapia. In the current study, we reported that tHsp70 alone and antigen-tHsp70 compound increased the proliferations of lymphocytes and macrophages, significantly increased the NO release and phagocytotic ability of macrophages (p<0.05), and enhanced the levels of immune-related genes in lymphocytes and macrophages in a dose- and/or time-dependent manner. On the other hand, tHsp70 not only helped to reduce the proliferation inhibitions induced by the ECP treatment, but also assisted antigens to enhance the vaccine-induced protection against Streptococcus iniae (p<0.05). We described, for the first time, a critical role of endotoxin-free tHsp70 on activation of tilapia lymphocytes and macrophages post S. iniae exposure and its up-regulation effects on vaccine-induced protection. Our research highlights the immunological enhancement action of Hsp70 in teleost immunity.

Effect of whole-body vibration exercise on mobility, balance ability and general health status in frail elderly patients: a pilot randomized controlled trial.

OBJECTIVE: To study the effects of whole-body vibration exercises on the mobility function, balance and general health status, and its feasibility as an intervention in frail elderly patients. DESIGN: Pilot randomized controlled trial. SUBJECTS: Forty-four frail older persons (85.27 ± 3.63 years) meeting the Fried Frailty Criteria. INTERVENTIONS: All eligible subjects were randomly assigned to the experimental group, who received a whole-body vibration exercise alone (vibration amplitude: 1-3 mm; frequency: 6-26 Hz; 4-5 bouts × 60 seconds; 3-5 times weekly), or a control group, who received usual care and exercises for eight weeks. MAIN MEASURES: The Timed Up and Go Test, 30-second chair stand test, lower extremities muscle strength, balance function, balance confidence and General Health Status were assessed at the beginning of the study, after four weeks and eight weeks of the intervention. RESULTS: Whole-body vibration exercise reduced the time of the Timed Up and Go Test (40.47 ± 15.94 s to 21.34 ± 4.42 s), improved the bilateral knees extensor strength (6.96 ± 1.70 kg to 11.26 ± 2.08 kg), the posture stability (surface area ellipse: 404.58 ± 177.05 to 255.95 ± 107.28) and General Health Status (Short-form Health Survey score: 24.51 ± 10.69 and 49.63 ± 9.85 to 45.03 ± 11.15 and 65.23 ± 9.39, respectively). The repeated-measures ANOVA showed that there were significant differences in the Timed Up and Go Test, 30-second chair stand test, bilateral knees extensor strength, activities-specific balance confidence score and general health status between the two groups (P < 0.05). No side-effects were observed during the training. CONCLUSIONS: Whole-body vibration exercise is a safe and effective method that can improve the mobility, knee extensor strength, balance and the general health status in the frail elderly.

[Clinical evaluation of a melting curve analysis-based PCR assay for glucose phosphate dehydrogenase gene mutation detection].

OBJECTIVE: To evaluate the clinical value of multicolor melting curve analysis(MMCA) for detecting genetic mutations in G6PD deficiency. METHODS: A total of 402 peripheral blood samples(256 males and 146 females) were collected from suspected patients or their relatives at the Prenatal Diagnosis Center of Liuzhou Maternal and Child Health Hospital between March 2012 and May 2012. The samples were screened by G6PD/6PGD quantitative ratio testing. The reliability of the assay was evaluated by multiplex probe melting curve assay(which can detect 16 G6PD mutations) and DNA sequencing through a double blind study. RESULTS: One hundred seventy cases with G6PD/6PGD ratio < 1.0 and 232 cases with G6PD/6PGD ratio ≥ 1.0 were detected by the enzymological method. DNA sequencing has identified 182 wild type samples, 151 hemizygous mutation samples, 5 female homozygous mutation samples, 54 female heterozygous mutation samples and 10 female double heterozygous mutation samples. Multicolor melting curve analysis has detected 185 wild type samples, 148 hemizygous mutation samples, 5 female homozygous mutation samples, 55 female heterozygous mutation samples and 9 female double heterozygous mutation samples. The specificity and sensitivity of G6PD gene mutation detection by multicolor melting curve analysis were 100%(182/182) and 98.6%(217/220), respectively. The positive predictive value and negative predictive value were 99.5%(216/217) and 98.4%(182/185), respectively, and the Youden's index was 0.986. The concordance rate of the sample detection between the melting curve assay and DNA sequencing was 99.0%(398/402). Twenty-one different genotypes were detected by the multicolor melting curve analysis and 24 different genotypes were detected by DNA sequencing. Four samples containing mutations(c.196T>A or c.406C>T) were not detected by multicolor melting curve analysis, which can be attributed to different technical settings of the two methods. CONCLUSION: Multicolor melting curve analysis for G6PD gene mutation detection is a simple, rapid, sensitive and specific method, which can be used for clinical diagnosis of G6PD deficiency.

Experimental study using the dilution incubation method to assess water biostability.

Water biostability is of particular concern to water supply as a major limiting factor for heterotrophic bacterial growth in water distribution systems. This study focused on bacterial growth dynamics in the series dilution of water samples with TOC (total organic carbon) values determined beforehand. The results showed that the specific growth rate of Pseudomonas fluorescens P17 varied dramatically and irregularly with TOC value when TOC concentrations were low enough during the initial periods of incubation under given conditions. According to this relationship between bacterial growth rate and TOC, a dilution incubation method was designed for the study of water biostability. With the method under a given condition, a turning-point TOC value was found at a relatively fixed point in the curve between bacterial growth rate and TOC of water sample, and the variation of growth rate had different characteristics below the turning-point TOC value relative to that over this value. A turning-point TOC value similarly existed in all experiments not only with tap water, but also with acetate and mixed solutions. And in the dilution incubation method study, the affections were analyzed by condition factors such as inoculum amount, incubation time and nature of the organic carbon source. In very low organic carbon water environments, the variation characteristics of bacterial growth rate will be useful to further understand the meaning of water biostability.

Multi-Dimensional Multiplexed Metasurface Holography by Inverse Design.

Multi-dimensional multiplexed metasurface holography extends holographic information capacity and promises revolutionary advancements for vivid imaging, information storage, and encryption. However, achieving multifunctional metasurface holography by forward design method is still difficult because it relies heavily on Jones matrix engineering, which places high demands on physical knowledge and processing technology. To break these limitations and simplify the design process, here, an end-to-end inverse design framework is proposed. By directly linking the metasurface to the reconstructed images and employing a loss function to guide the update of metasurface, the calculation of hologram can be omitted; thus, greatly simplifying the design process. In addition, the requirements on the completeness of meta-library can also be significantly reduced, allowing multi-channel hologram to be achieved using meta-atoms with only two degrees of freedom, which is very friendly to processing. By exploiting the proposed method, metasurface hologram containing up to 12 channels of multi-wavelength, multi-plane, and multi-polarization is designed and experimentally demonstrated, which exhibits the state-of-the-art information multiplexing capacity of the metasurface composed of simple meta-atoms. This method is conducive to promoting the intelligent design of multifunctional meta-devices, and it is expected to eventually accelerate the application of meta-devices in colorful display, imaging, storage and other fields.