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Existing vehicle re-identification methods mainly rely on the single query, which has limited information for vehicle representation and thus significantly hinders the performance of vehicle Re-ID in complicated surveillance networks. In this paper, we propose a more realistic and easily accessible task, called multi-query vehicle Re-ID, which leverages multiple queries to overcome viewpoint limitation of single one. Based on this task, we make three major contributions. First, we design a novel viewpoint-conditioned network (VCNet), which adaptively combines the complementary information from different vehicle viewpoints, for multi-query vehicle Re-ID. Moreover, to deal with the problem of missing vehicle viewpoints, we propose a cross-view feature recovery module which recovers the features of the missing viewpoints by learnt the correlation between the features of available and missing viewpoints. Second, we create a unified benchmark dataset, taken by 6142 cameras from a real-life transportation surveillance system, with comprehensive viewpoints and large number of crossed scenes of each vehicle for multi-query vehicle Re-ID evaluation. Finally, we design a new evaluation metric, called mean cross-scene precision (mCSP), which measures the ability of cross-scene recognition by suppressing the positive samples with similar viewpoints from same camera. Comprehensive experiments validate the superiority of the proposed method against other methods, as well as the effectiveness of the designed metric in the evaluation of multi-query vehicle Re-ID.

Additional file 3: Fig. S3. Sensitive analysis.

Additional file 4: Fig. S4. Main microbial pathogens including bacteria, virus, fungi, and others detected by mNGS within HHV-7-positive and HHV-7-negative BALF. All data represent the number of times pathogens were detected within different groups, not the number of patients.

Additional file 2: Fig. S2. The results of multivariable analyses for 28-day all-cause mortality with the Cox regression model, p < 0.05 were considered statistically significant and shown in bold.

Additional file 1: Fig S1. Study profile.

Background. Endomertrial adenocarcinoma (EC) with early stage, high grade is rare seen metastasis. Here, we describe a unique case of axillary lymph node and breast metastasis from high grade endomertrial adenocarcinoma after a 4-year period. Cases. We presented a case of a 60-year-old woman with EC and received surgery in 2013. However, a metastatic tumor appeared at the axillary lymph node and the breast 4 years after surgery. Then she received an operation and 6 cycles adjuvant chemotherapy. 31 months following, she is alive without disease. Conclusions. A correct diagnosis should be made by combining the patient’s past clinical history, morphologic and immunohistochemical test results. Knowledge of this rare metastatic site will help the physician make the correct diagnosis.

Titanium alloy powders were prepared from titanium rods by plasma rotating electrode process (PREP). The effects of powder preparation technology on the morphology and properties of titanium alloy powders were studied by laser particle size analyzer, scanning electron microscope (SEM), X-ray diffraction, powder comprehensive property tester and oxygen nitrogen analyzer. The results shown that the titanium alloy powder prepared by PREP had uniform particle size distribution, sphericity >93% and oxygen content

Large active-area superconducting nanowire single-photon detectors (SNSPDs) coupled with multimode fibers (MMFs) can provide high light-gathering capacity, which is essential for free-space detection applications in photon-starved regimes. However, MMF-coupled SNSPDs often suffer from large system dark count rates (DCRsys) over kHz due to blackbody radiation of the MMF at room temperature. Such large DCRsys would significantly degrade signal-to-noise ratio (SNR) of the receiving system. This paper reports an MMF-coupled large-active-area SNSPD system with low DCRsys by using a homemade cryogenic MMF filter bench. The filter bench, which consists of lenses and optical filters, can provide a high transmittance of about 80% at the central wavelength of the passband (1550 ± 12.5 nm) and a wide blocking range from 500 nm to over 6000 nm at 40 K. With using the filter bench, the DCRsys of an MMF-coupled 9-pixel SNSPD array with an active area of 50 μm in diameter is greatly suppressed by 23 dB with 1 dB loss of system detection efficiency (SDE). The detector demonstrates an SDE of 51% at a DCRsys of 100 Hz for 1550 nm photons. Thus, SNR of the detector is enhanced by about 160 times and the noise equivalent power is improved to 3×10-19 W/Hz1/2.

The absolute absorption cross section of the ethyl peroxy radical, C2H5O2, in the Ã←X ̃ electronic transition with the peak wavelength at 7596 cm-1, has been determined by the method of dual wavelengths time resolved continuous wave cavity ring down spectroscopy. C2H5O2 radicals were generated from pulsed 351 nm photolysis of C2H6/Cl2 mixture in presence of O2 and detected on one of the CRDS paths. Two methods have been applied for the determination of the C2H5O2 absorption cross section: (i) based on Cl-atoms being converted alternatively to either C2H5O2 by adding C2H6 or to hydro peroxy radicals, HO2, by adding CH3OH to the mixture, whereby HO2 was reliably quantified on the second CRDS path in the 21 vibrational overtone at 6638.2 cm-1 (ii) based on the reaction of C2H5O2 with HO2, measured under either excess HO2 or under excess C2H5O2 concentration. Both methods lead to the same peak absorption cross section of C2H5O2,7596 cm-1 = (1.0±0.2) × 10-20 cm2. The rate constant for the cross reaction between of C2H5O2 and HO2 has been measured to be (6.5±1.6) × 10-12 cm3 molecule-1 s-1.

Increasing the count rate (CR) is one of the key issues in the development of superconducting nanowire single-photon detectors (SNSPDs) for different applications. This study aims to design, fabricate, and analyze a 16-pixel interleaved nanowire SNSPD array, which exhibits a system detection efficiency (SDE) of 72% and a dark CR of 100 Hz at a low-photon-flux limit and a wavelength of 1550 nm. By exploiting the increased pixel number and reduced dead time (

Allochthonous (e.g., riparian) plant litter is among the organic matter resources that are important for wetland ecosystems. A compact canopy of free‐floating vegetation on the water surface may allow for riparian litter to remain on it for a period of time before sinking to the bottom. Thus, we hypothesized that canopy of free‐floating vegetation may slow decomposition processes in wetlands. To test the hypothesis that the retention of riparian leaf litter on the free‐floating vegetation in wetlands affects their subsequent decomposition on the bottom of wetlands, a 50‐day in situ decomposition experiment was performed in a wetland pond in subtropical China, in which litter bags of single species with fine (0.5 mm) or coarse (2.0 mm) mesh sizes were placed on free‐floating vegetation (dominated by Eichhornia crassipes, Lemna minor, and Salvinia molesta) for 25 days and then moved to the pond bottom for another 25 days or remained on the pond bottom for 50 days. The leaf litter was collected from three riparian species, that is, Cinnamomum camphora, Diospyros kaki, and Phyllostachys propinqua. The retention of riparian leaf litter on free‐floating vegetation had significant negative effect on the carbon loss, marginal negative effects on the mass loss, and no effect on the nitrogen loss from leaf litter, partially supporting the hypothesis. Similarly, the mass and carbon losses from leaf litter decomposing on the pond bottom for the first 25 days of the experiment were greater than those from the litter decomposing on free‐floating vegetation. Our results highlight that in wetlands, free‐floating vegetation could play a vital role in litter decomposition, which is linked to the regulation of nutrient cycling in ecosystems.

Ping Yang,1,* Ran Cao,2,* Hua Bao,2 Xue Wu,2 Lingling Yang,2 Dongqin Zhu,2 Lu Zhang,3 Liming Peng,4 Yuefei Cai,5 Weijun Zhang,6 Yang Shao2,7 1Department of Radiation Oncology, Tungwah Hospital of Sun Yat-Sen University, Dongguan, Guangdong, People’s Republic of China; 2Nanjing Geneseeq Technology Inc., Nanjing, Jiangsu, People’s Republic of China; 3Department of Medical Oncology, Tungwah Hospital of Sun Yat-Sen University, Dongguan, Guangdong, People’s Republic of China; 4Department of Respiratory Medicine, Tungwah Hospital of Sun Yat-Sen University, Dongguan, Guangdong, People’s Republic of China; 5Department of Intervention, Tungwah Hospital of Sun Yat-Sen University, Dongguan, Guangdong, People’s Republic of China; 6Departments of Radiation Oncology, Cancer Center of Guangzhou Medical University, Guangzhou, Guangdong, People’s Republic of China; 7School of Public Health, Nanjing Medical University, Nanjing, Jiangsu, People’s Republic of China*These authors contributed equally to this workCorrespondence: Ping YangDepartments of Radiation Oncology, Tungwah Hospital of Sun Yat-Sen University, Dongguan, Guangdong, 523110, People’s Republic of ChinaEmail yp150077677@163.comYang ShaoNanjing Geneseeq Technology Inc., Nanjing, Jiangsu, 210032, People’s Republic of ChinaEmail yang.shao@geneseeq.comBackground: Drug resistance caused by G1202R/G1202del mutation in anaplastic lymphoma kinase (ALK) represents a great challenge in the clinic. The effect of other mutation(s) at G1202 on the available tyrosine kinase inhibitors (TKIs) in the clinic remains unknown.Case Presentation: A 50-year-old Chinese male non-smoker with lung adenocarcinoma progressed with spinal metastasis after receiving chest radiation together with Pemetrexed and Cisplatin as adjuvant chemotherapy. Targeted next generation sequencing (NGS) identified EML4-ALK gene fusion in the resected left lung tissue. Local radiation followed by Crizotinib were used in the following treatment and the spinal metastasis was found to shrink, but the progression free survival (PFS) only lasted for 2 months with the appearance of brain metastasis. Afterwards, the patient benefited from the therapy of Alectinib with a PFS of 8 months. Then he progressed with metastases in right lung and pleural, and did not show response to the chemotherapy with Docetaxel plus Bevacizumab. The targeted sequencing consistently identified EML4-ALK gene fusion in both plasma and pleural effusion (PE), as well as a novel ALK G1202K mutation (c.3604_3605delGGinsAA). Given the lack of established or known drug treatment for this novel mutation, we implemented molecular dynamics (MD) simulation-guided drug sensitivity prediction, which results suggested Lorlatinib remains potent against G1202K mutant ALK. Therefore, Lorlatinib was used as the fourth-line therapy, which lead to the considerable efficacy with improved performance status (PS) score and reduced lung metastases. The structural mechanism underlying G1202K-induced drug resistance to different ALK-TKIs was also discussed.Conclusion: Our case suggested the ALK-G1202K mutation may serve as a novel mechanism underlying the resistance to Alectinib, and provide direct evidence to support its sensitization to Lorlatinib. Our work represented an example of integrating in silico predictions into clinical practice.Keywords: lung cancer, drug resistance, in silico prediction, binding energy calculation, Alectinib, Lorlatinib

We report a compact, scalable, and high-performance superconducting nanowire single-photon detector (SNSPD) array by using a multichannel optical fiber array-coupled configuration. For single pixels with an active area of 18 µm in diameter and illuminated at the telecom wavelength of 1550 nm, we achieved a pixel yield of 13/16 on one chip, an average system detection efficiency of 69% at a dark count rate of 160 cps, a minimum timing jitter of 74 ps, and a maximum count rate of ∼ 40 M c p s . The optical crosstalk coefficient between adjacent channels is better than − 60 d B . The performance of the fiber array-coupled detectors is comparable with a standalone detector coupled to a single fiber. Our method is promising for the development of scalable, high-performance, and high-yield SNSPDs.

Donglan Huang,1,* Chunyue Huang,1,* Hongmei Wang,1,* Lizhen He,1,2,* Jian Zhang,1,* Xi Zhong,1,3 Ziqian Guo,1,4 Yawei Yuan,1 Weijun Zhang1 1Department of Radiation Oncology, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, People’s Republic of China; 2Department of Pathology, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, People’s Republic of China; 3Department of Radiology, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, People’s Republic of China; 4Endoscopy Center, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, People’s Republic of China*These authors contributed equally to this workCorrespondence: Weijun Zhang; Yawei YuanDepartment of Radiation Oncology, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, 78 Hengzhigang Road, Guangzhou, 510095, People’s Republic of ChinaTel + 86 20 66673662; +86 20 62931358Email weijunzhang@gzhmu.edu.cn; yuanyawei@gzhmu.edu.cnAbstract: The incidence of primary mixed adenoneuroendocrine carcinoma (MANEC) is rapidly increasing. MANEC mainly arises from the gastrointestinal tract, but occasionally it occurs as a pathological type of second primary malignancy (SPM). These SPMs can occur in the nasopharynx. Herein we describe the case of a first secondary nasopharyngeal MANEC that was detected 20 years after radical radiotherapy for nasopharyngeal carcinoma. The patient was a 50-year-old man who was admitted to our hospital after experiencing 1 month of left nasal congestion and ipsilateral tinnitus caused by a nasopharyngeal mass that was detected via physical examination and magnetic resonance imaging. A biopsy specimen from this nasopharyngeal lesion led to a histopathological diagnosis of recurrent nasopharyngeal carcinoma. He underwent high-dose palliative radiotherapy, followed by a course of gemcitabine–cisplatin-based adjuvant chemotherapy. These treatments failed to achieve local control of the tumor, and progressive left earache emerged. Another two forceps biopsies of the external auditory canal mass were conducted, and immunohistochemical testing for adenocarcinoma and neuroendocrine carcinoma markers including CK7, CK8, CK18, carcinoembryonic antigen, synaptophysin, chromogranin A, and CD56 was conducted. The diagnosis of MANEC was ultimately confirmed 5 months after the first visit, and one additional cycle of chemotherapy was subsequently performed. The patient died of hepatic metastases 8 months after the final diagnosis. Knowledge of this rare case will raise awareness of MANEC as a new pathological type of SPM originating in the nasopharynx, which will reduce delays and promote early diagnosis.Keywords: adenocarcinoma, head and neck, neuroendocrine carcinoma, second primary malignancy

Background The overall genetic distribution and divergence of cloned genes among bread wheat varieties that have occurred during the breeding process over the past few decades in Ningxia Province, China, are poorly understood. Here, we report the genetic diversities of 44 important genes related to grain yield, quality, adaptation and resistance in 121 Ningxia and 86 introduced wheat cultivars and advanced lines. Results The population structure indicated characteristics of genetic components of Ningxia wheat, including landraces of particular genetic resources, introduced varieties with rich genetic diversities and modern cultivars in different periods. Analysis of allele frequencies showed that the dwarfing alleles Rht-B1b at Rht-B1 and Rht-D1b at Rht-D1, 1BL/1RS translocation, Hap-1 at GW2-6B and Hap-H at Sus2-2B are very frequently present in modern Ningxia cultivars and in introduced varieties from other regions but absent in landraces. This indicates that the introduced wheat germplasm with numerous beneficial genes is vital for broadening the genetic diversity of Ningxia wheat varieties. Large population differentiation between modern cultivars and landraces has occurred in adaptation genes. Founder parents carry excellent allele combinations of important genes, with a higher number of favorable alleles than modern cultivars. Gene flow analysis showed that six founder parents have greatly contributed to breeding improvement in Ningxia Province, particularly Zhou 8425B, for yield-related genes. Conclusions Varieties introduced from other regions with rich genetic diversity and landraces with well-adapted genetic resources have been applied to improve modern cultivars. Founder parents, particularly Zhou 8425B, for yield-related genes have contributed greatly to wheat breeding improvement in Ningxia Province. These findings will greatly benefit bread wheat breeding in Ningxia Province as well as other areas with similar ecological environments.

Generally, a superconducting nanowire single-photon detector (SNSPD) is composed of wires with a typical width of ~100 nm. Recent studies have found that superconducting strips with a micrometer-scale width can also detect single photons. Compared with the SNSPD, the superconducting microstrip single-photon detector (SMSPD) has smaller kinetic inductance, higher working current, and lower requirement in fabrication accuracy, providing potential applications in the development of ultra-large active area detectors. However, the study on SMSPD is still in its infancy, and the realization of its high-performance and practical use remains an opening question. This study demonstrates a NbN SMSPD with a saturated system detection efficiency (SDE) of ~92.2% at a dark count rate of ~200 cps, a polarization sensitivity of ~1.03, and a minimum timing jitter of ~48 ps, at the telecom wavelength of 1550 nm when coupled with a single mode fiber and operated at 0.84 K. Furthermore, the detector's SDE is over 70% when operated at a 2.1-K closed-cycle cryocooler., 10 pages,7 figures, 2 tables

Xuejun Wang,1,* Hongmei Wang,1,* Baochang Jia,1 Fang He,2 Yawei Yuan,1 Weijun Zhang1 1Department of Radiation Oncology, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, Guangdong Province, People’s Republic of China; 2Department of Radiation Oncology, Zhongshan City People’s Hospital, Zhongshan, Guangdong Province, People’s Republic of China*These authors contributed equally to this workCorrespondence: Weijun Zhang; Hongmei WangDepartment of Radiation Oncology, Affiliated Cancer Hospital & Institute of Guangzhou Medical University, Guangzhou, Guangdong Province, People’s Republic of ChinaTel +86 136 8887 9087Email 591533086@qq.com; hongmeiW1988@163.comAbstract: Cutaneous metastasis from a primary visceral malignancy is a relatively uncommon clinical manifestation that occurs as an initial presentation in 1% to 12% of patients with internal malignancies. Additionally, cutaneous metastases are often late signs of an internal malignancy, and in very rare cases they may occur at the same time or before the primary cancer has been detected. Metastasis to the skin has a poor prognosis and is often a sign of widespread malignant tumors. In the present study, we report a 72-year-old male who presented with multiple rapidly growing subcutaneous nodules. Positron emission tomography-computed tomography (PET-CT) revealed a hypermetabolic concentration of radiotracer in the left lower lung and multiple organ metastases associated with multiple skin masses. Biopsy of one of the skin nodules and gene detection indicated metastatic adenocarcinoma consistent with a primary lung origin with a BRAF mutation. BRAF mutations are emerging therapeutic targets in non-small-cell lung cancer (NSCLC), as they are present in 2– 4% of NSCLC cases. To the best of our knowledge, this is the first case report to show that BRAF-mutant lung adenocarcinoma can be associated with cutaneous metastasis. Early diagnosis and individualized treatment strategies may prolong patient survival.Keywords: metastasis, skin lesion, lung adenocarcinoma, BRAF mutation

Background: The overall genetic distribution and divergences for cloned genes among wheat varieties that occurred during the breeding process of the past few decades in Ningxia province of China are poorly understood. Here we report the genetic diversities of 44 important genes underpinning grain yield, quality, adaptation and resistance in 121 Ningxia and 86 introduced wheat cultivars and advanced lines.Results: Population structure indicated characteristics of genetic components of Ningxia wheats including landraces of particular genetic resources, introduced varieties with rich genetic diversities and modern cultivars in different times. Analysis of allele frequencies showed that dwarfing alleles Rht-B1b at Rht-B1 and Rht-D1b at Rht-D1 , 1BL/1RS translocation, Hap-1 at GW2-6B and Hap-H at Sus2-2B are present very frequently in Ningxia modern cultivars and introduced varieties from other regions, but absent in landraces, indicating that the introduced wheat germplasm with numerous beneficial genes are vital for broadening genetic diversities of Ningxia wheat varieties. Large population differentiation occurred at adaptation genes between modern cultivars and well-adapted landraces. Founder parents have excellent allele combinations of important genes with a higher number of favorable alleles compared with modern cultivars. The gene flows manifested that six founder parents greatly contributed to breeding improvement in Ningxia province, in particular Zhou 8425B for yield related genes.Conclusions: These results will greatly benefit for wheat breeding in Ningxia province and other areas with similar ecological environments.

Typhoon disaster can result in wind farms shutdown. With the large-scale integration of wind farms in power system, the wind farms shutdown may affect the operation of power system, causing the power shortage and voltage violation. In this paper, a shutdown risk assessment method is proposed to evaluate the risk of wind farms operation under typhoon disaster. Firstly, the distribution of forecast error of wind power under typhoon conditions is analyzed according to the historical data and is established as T distribution. Next, the real-time shutdown probability of wind farms is generated by the known cumulative error distribution. Then, the shutdown cost of wind farms are expressed by the cost of shedding load after wind power exiting, which is solved by particle swarm optimization method. Finally, the adjusted IEEE-33 node system with wind farms are adopted to verify the effectiveness of proposed method.

Most of the small-size hydropower stations are runoff hydropower stations and their output is determined by the upstream water supply. Consequently, the rainfall brought by typhoons will lead to the increment of runoff, increasing the output of small-size hydropower stations. The uncertain increment of the output of small-size hydropower stations will bring adverse effects on the security of power system, such as the voltage over-limit and the power overload of transmission lines. In this paper, a risk assessment method is proposed to assess the shutdown risk of small-size hydropower station under typhoon disaster. Firstly, Monte Carlo Method is employed to calculate the probabilistic load flow of power system with small-size hydropower station and the probability of node voltage over-limit and branch power overload is set to be the shutdown probability of small-size hydropower station. Secondly, the cost of load shedding which is optimized by Adaptive Particle Swarm optimization (APSO) algorithm is set to be the shutdown cost of small-size hydropower station. Finally, the IEEE-33 bus system is used to assess the shutdown risk of small-size hydropower station under typhoon disaster.

Frequent typhoons may threaten the operation security of coastal power system with high wind power integration, inducing severe wind power rapid climbs and line active power violations. Aiming at the phenomenon and problems in real typhoon disasters, this paper proposes a multisource coordinated dispatching strategy for high wind power penetration system under typhoon environment. In this paper, a wind farm output model considering wind speed is established. Besides, the profiles and fitting effects of different wind fields are compared. In the end of this paper, a multi-objective security constrained economic dispatch strategy during typhoons is proposed. The analysis of the regional system validates that the proposed dispatch strategy is feasible for the security improvement of the power system during typhoons.

Combined cooling, heating and power (CCHP) system is an eco-friendly energy utilization manner, whose equipment capacity and operation strategy require rigorous design to give full play to its advantages. In this paper, an optimization model based on the genetic algorithm (GA) is established to realize the capacity and operation strategy optimization for the CCHP system simultaneously. Also eight evaluation criteria considering economic, energy, exergy and ecological (4E) aspects are formulated to evaluate the system comprehensively. Besides, considering the effects of the feed-in tariff on the system scheme and performance, detailed contrastive discussions are performed based on the optimization results. Taking an office building situated in Xian, China as the specific case, the results show that, the implement of the feed-in tariff will reduce the annual total cost of the CCHP system, meanwhile, reducing the dependency of the system on power grid. After running with the feed-in tariff, the economic, energy, exergy and ecological performance of the system are all be improved. The superiority of the CCHP system is more obvious during the heating seasons than during the cooling seasons.

Intermediate heat carriers have been applied in engineering as enhanced heat transfer elements, but their theoretical analysis still needs to be improved. Therefore, an intermediate heat carrier is added to establish the quaternary model of the furnace gas under nongray radiation characteristics. Based on this model, an analytical expression of heat flux on the surface of the billet is derived. General rule of the impact of intermediate heat carrier on the thermal efficiency in the furnace can be properly derived by analytical calculation from a theoretical point of view. The results show that the longer the length of the intermediate heat carrier located at the top of the furnace, the greater the heat exchange capacity on the surface of the billet. Meanwhile, when the intermediate heat carrier is located in the center of the furnace top, the billet gets higher heat flux; the closer to both sides, the lower the heat flux. In addition, the influence that the surface emissivity of the intermediate heat carrier has on the heat transfer of the billet surface is related to the values of εg and αgw. Comparison with previous literature shows that adding intermediate heat carrier can improve the heat exchange capacity of billet.

The battery energy storage station (BESS) is developing from the demonstration project to the stage of business promotion. Due to the unsound Economic benefit evaluation, which restricts the large-scale promotion and construction of BESS. This paper establishes the life cycle cost and income model of BESS and uses the dynamic investment payback period, net present value (NPV), internal rate of return (IRR) and other economic indicators to analyze the economy of offshore wind power with BESS in peak shaving auxiliary service market. At the same time, aiming at stimulating the enthusiasm of the wind farm to allocate energy storage, we studied the improvement of the market regulation rules and government subsidies. The research results can provide an engineering economic reference for the investment decision of BESS and the government to guide the development of energy storage.

Superconducting nanowire single-photon detectors (SNSPDs) with high system detection efficiency (SDE) would enable remarkable experiments in quantum information processing. However, realizing a NbN SNSPD with saturated intrinsic detection efficiency (IDE) that retains high SDE at near-infrared wavelengths is challenging, due to the high critical temperature of NbN. This study uses defect engineering by helium-ion irradiation to enhance the IDE of NbN SNSPDs to saturation without sacrificing SDE. This technique also allows direct comparison of irradiation-induced changes in detector performance, making it a useful tool for studying the physics of superconducting devices.

Wind power generation systems include slow-changing mechanical systems such as wind turbines and drivelines, as well as fast-changing power electronic controls and protection of electrical systems such as surveys, hybrid systems with multiple time scales. It is very important to develop the transient model of wind power with high accuracy to meet the stability analysis of power system as much as possible to meet the actual operating characteristics of wind turbine. This paper focuses on the need of system stability analysis after large-scale wind power integration. Based on the accurate reflection of the failure-tracing wind farm model of wind turbine under grid fault, this paper evaluates the system security and stability after a large number of wind power grid-connected.

Organic acids secreted from the roots of plants play important roles in nutrient acquisition and metal detoxification; however, the precise underlying mechanisms of these processes remain poorly understood. In the present study we examined the content of organic acids exuded from roots and the effects of these organic acids on the activation of slowly available potassium (K) at different K levels, including normal K supply and K-deficient conditions. In addition, the study system also comprised a high-K tobacco variety (ND202) and two common ones (K326 and NC89). Our results showed that high-K varieties exhibited significantly higher contents of organic acids in its root exudates and available K in both rhizosphere and non-rhizosphere soils than the other varieties. This research also suggested that a cyclic process in which soil was acidified after being complexed by organic acids was involved in the release of slowly available K, and that this process primarily depended on the soil pH at high organic acids concentrations, but the complexation of organic ligands became dominant at low concentrations. In conclusion, tobacco roots secrete organic acids to increase available K content and improve the utilisation rate of soil K. High-K varieties probably enhance slowly available K activation by secreting relatively high amounts of organic acids, thus leading to more available K in soil for absorption by plants.

In order to study the supraharmonic transmission and propagation characteristics of photovoltaic grid-connected inverter, a more accurate model of photovoltaic grid-connected inverter was proposed based on PSCAD simulation software. Firstly, the model of the photovoltaic system is built. Secondly, the inverter control method suitable for dynamic analysis of grid connection is modeled, and the voltage and current double loop control strategy is adopted to realize the decoupling control of active and reactive power. Finally, a simulation model was built and the influence of the main parameters of the photovoltaic system, such as illumination, temperature and switching frequency, on the level of the supraharmonic emitted by it was analyzed. And then the correctness of the model is verified by comparison with the field measured data. The model provides an effective simulation platform for verifying the superaharmonic current and voltage emissions of photovoltaic grid-connected inverters under working conditions.

Quantum key distribution (QKD offers a long-term solution to establish information-theoretically secure keys between two distant users. In practice, with a careful characterization of quantum sources and the decoy-state method, measure-device-independent quantum key distribution (MDI-QKD) provides secure key distribution. While short-distance fibre-based QKD has already been available for real-life implementation, the bottleneck of practical QKD lies on the limited transmission distance. Due to photon losses in transmission, it was believed that the key generation rate is bounded by a linear function of the channel transmittance, $O(\eta)$, without a quantum repeater, which puts an upper bound on the maximal secure transmission distance. Interestingly, a new phase-encoding MDI-QKD scheme, named twin-field QKD, has been suggested to beat the linear bound, while another variant, named phase-matching quantum key distribution (PM-QKD), has been proven to have a quadratic key-rate improvement, $O(\sqrt{\eta})$. In reality, however, the intrinsic optical mode mismatch of independent lasers, accompanied by phase fluctuation and drift, impedes the successful experimental implementation of the new schemes. Here, we solve this problem with the assistance of the laser injection technique and the phase post-compensation method. In the experiment, the key rate surpasses the linear key-rate bound via 302 km and 402 km commercial-fibre channels, achieving a key rate over 4 orders of magnitude higher than the existing results in literature. Furthermore, with a 502 km ultralow-loss fibre, our system yields a secret key rate of 0.118 bps. We expect this new type of QKD schemes to become a new standard for future QKD., Comment: 16 pages, 7 figures

In our previous work ( Yang et al. Anal. Chem. 2018 , 90 ( 5 ), 3307 - 3312 ), we reported that a large diameter Nafion dryer can be used in the PERCA (PEroxy Radical Chemical Amplification) technique to minimize the impact of water vapor on the chain length (CL). By using a Nafion dryer, the sample was first dried to a low relative humidity (RH) and was then drawn into a FEP (fluorinated ethylene propylene) flow reactor tube to start the amplification cycles for peroxy radical measurement. This method provides a promising and simple method to minimize the sensitivity of CL to water vapor. However, there is a trade-off between inlet radical losses and moisture removal efficiency under high ambient RH conditions. In this paper, we report a further improvement by removing the inlet Nafion dryer and using it directly as an amplifier. The sample was drawn into the Nafion dryer directly without preconditioning to reduce inlet losses; the amplification and HO2 reformation cycles were started in the Nafion dryer. The CL value at 3% RHinlet was about 150. A linear relationship between CL and RHinlet up to 87% RH was observed. Low loss of the CL under high RHinlet (about 10% reduction at 87% RH) was achieved. As a result, the modified system can largely remove the uncertainty of the CL arising from water vapor under most ambient conditions.

Superconducting nanowire single-photon detectors (SNSPDs) have attracted remarkable interest for visible and near-infrared single-photon detection due to their outstanding performance. However, conventional SNSPDs are generally used as binary photon-counting detectors. Another important characteristic of light, i.e., polarization, which can provide additional information of the object, has not been resolved using the standalone SNSPD. In this work, we present a first prototype of the polarimeter based on a four-pixel superconducting nanowire array, capable of resolving the polarization state of linearly-polarized light at the single-photon level. The detector array design is based on a division of focal plane configuration in which the orientation of each nanowire division (pixel) is offset by 45°. Each single nanowire pixel operates as a combination of a photon detector and almost linear polarization filter, with an average polarization extinction ratio of ∼10. The total system detection efficiency of the array is ∼1% at a total dark count rate of 680 cps, with a timing jitter of 126 ps, when the detector array is free-space coupled and illuminated with 1550-nm photons. The mean errors of the measured angle of polarization and degree of linear polarization were about -3° and 0.12, respectively. Furthermore, we successfully demonstrated polarization imaging at low-light level using the proposed detector. Our results pave the way for the development of a single-photon sensitive, fast, and large-scale integrated polarization polarimeter or imager. Such detector may find promising application in photon-starved polarization resolving and imaging with high spatial and temporal resolution.

At present, China has overtaken the United States to become the world’s largest new energy vehicle market. Due to differences in developmental trajectory, developmental mode, and charging standards, China and the U.S. have common interests and the foundation for cooperation, which can work together for a win-win development. Charging interoperability is the basis for ensuring charging safety and interchangeability of electric vehicles. This study examined and compared the differences between China and the U.S. in the standards for conductive AC charging of electric vehicles. The requirements for a control pilot circuit, proximity circuit, current capacity, and charging-state transition timing were analysed. Hierarchical and layered interoperability test cases based on GB/T 34657 and SAE J2953 series were presented. A dual interface interoperability test system was constructed and used to verify the test method rationale. The results provided a mutual inspection solution for AC charging equipment between China and the U.S. and accelerated global application and promotion of the electric vehicle industry.

The implementation of quantum information technologies requires the development of integrated quantum chips. Femtosecond laser direct writing (FLDW) waveguides and superconducting nanowire single-photon detectors (SNSPDs) have been widely applied in integrated quantum photonic circuits. In this work, a novel FLDW waveguide-coupled SNSPD was designed and realized by integrating FLDW waveguides and conventional SNSPDs together. Through a COMSOL simulation, a waveguide end face-nanowire optical coupling structure was designed and verified. The simulation results showed that the FLDW waveguide-coupled SNSPD device, which had a target wavelength of 780 nm, can achieve 87% optical absorption. Then the preparation process of the FLDW waveguide-coupled SNSPD device was developed, and the fabricated device achieved a system detection efficiency of 1.7% at 10 Hz dark count rate. Overall, this method provides a feasible single-photon detector solution for future on-chip integrated quantum photonic experiments and applications.

Silica aerogels have been successfully synthesized using cationic cetyltrimethylammonium bromide (CTAB) and anionic sodium dodecyl sulfate (SDS) as template. This study provides a novel approach to synthesize silica aerogels. The molar ratio of surfactant mixture was CTAB/SDS = 1.00. The obtained silica aerogels exhibit very low apparent density (0.044 g cm −3 ) and high specific surface area (856 m 2 g −1 ). Surfactant packing parameter theory is used to explain the possible formation mechanism of the silica aerogels using mixed surfactant template. In addition, the adsorption capacity of Rhodamine B on the as-synthesized silica aerogels is as higher as that on the commercial silica aerogels.

Thepaper studies the effect of automatic generation control(AGC) on power frequency based on the full dynamic simulation. First modeling of AGC for the full dynamic simulation according to the three components of AGC, which is calculation of area control error (ACE), simulation of control strategy, and calculation of generating power regulation. Second the effect of key-parameters of AGC including dead band, transient frequency-deviationon and rate of generating power regulation on power frequency is studied by simulating. Finally, the paper takes Fujian power as an example to analyze the effect of AGC on under-frequency loading shedding(UFLS) by the serious faults and study on the coordination control between AGC and UFLS.

Harmonic distortion in the frequency range 2 to 150 kHz is referred to as supraharmonic. The influence of supraharmonic on power grid has become a concern with increasing modern power electronic devices connected into power grid. Determining responsibility is the premise for controlling and managing supraharmonic. Since harmonics of a point of common coupling (PCC) are commonly produced by both utility side and customer side, it is important to determine which side is the dominant harmonic source and quantify their respective responsibilities. Considering supraharmonic sources of both sides are approximately independent, the complex independent component analysis (Complex ICA) method is used to obtain the mixed matrix and supraharmonic impedances of both sides. Meanwhile, a new index for judging dominant supraharmonic source is proposed by vector projection technique. Project the supraharmonic voltages, which are produced respectively by the supraharmonic sources of the utility side and the customer side, to the measured voltage of a PCC. By comparing the value of the projection, if the value of one side is larger than half of the supraharmonic voltage of the PCC, it can be considered to be a dominant harmonic source. The method can determine the position of dominant supraharmonic source and quantify the responsibility, which provides new ideas for the supraharmonic source tracing. Validity and effectiveness are verified by simulation analysis.

Borosilicate glass with the additions of Al 2 O 3 (40~55%) composites were sintered at 850°C. Different qualitative and quantitative instruments were used to employ the influence mechanism of the different Al 2 O 3 contents on the properties of the composites. Composites with 45wt% Al 2 O 3 sintered at 850°C presented great performance: the bulk density of 2.51 g/cm3, the dielectric constant of 5.27 and the dielectric loss of 0.0027 at 1 MHz, the thermal expansion coefficient of 5.79*10−6 ppm/°C, the flexural strength of 142.5MPa and the weight loss of 2.78 mg/cm2 after soaking in 1 mol/L nitric acid Solution. The composite could meet the shrinkage requirement of Ag electrodes and could not possibly react with Ag electrodes any more. The metallized substrate can withstand the electroless nickel immersion gold process.

Realizing an NbN superconducting nanowire single-photon detector (SNSPD) with a 100% intrinsic detection efficiency (IDE) at the near-infrared wavelengths is still challenging. Herein, we developed a post-processing method to increase the IDE of NbN SNSPDs to near unity using a 20 keV helium ion irradiation. The IDE enhancement was achieved owing to the ion-induced reduction of the superconducting energy gap and the electron density of states at the Fermi level, determined with the electrical and magnetic transport measurements. The change in optical absorptance of the irradiated SNSPD was negligible as confirmed by the measured optical reflectance and system detection efficiency (SDE). Benefited with the IDE enhancement, the SDE of an irradiated device was significantly increased from 49% to 92% at 2.2 K for a 1550 nm wavelength., Comment: 5 pages, 2 figures, 2 tables

Covert communication offers a method to transmit messages in such a way that it is not possible to detect that the communication is happening at all. In this work, we report an experimental demonstration of covert communication that is provably secure against unbounded quantum adversaries. The covert communication is carried out over 10 km of optical fiber, addressing the challenges associated with transmission over metropolitan distances. We deploy the protocol in a dense wavelength-division multiplexing infrastructure, where our system has to coexist with a co-propagating C-band classical channel. The noise from the classical channel allows us to perform covert communication in a neighbouring channel. We perform an optimization of all protocol parameters and report the transmission of three different messages with varying levels of security. Our results showcase the feasibility of secure covert communication in a practical setting, with several possible future improvements from both theory and experiment., 13 pages, 5 figures

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Background Recurrent aphthous stomatitis (RAS) is one of the most common chronic oral diseases with morbidity ranging from 5% to 20%. The pathogenesis is still not fully understood though immune dysregulation and local trauma have been implicated and the curative effect that can be achieved through current therapy is mainly to alleviate the pain. So, the understanding of its molecular mechanisms can allow the prevention and treatment of RAS at the molecular level. Methods 14 normal tissues and 14 ulcerated tissues were subjected to Affymetrix Human Genome U133 Plus 2.0 Array transcriptome analysis. Then, Gene Set Expression Analysis and Gene Pattern tools were carried out to determine the gene expression differences between normal and ulcerated tissues. qRT-PCR was used to validate the expression level of identified genes in 10 normal and 10 ulcerated tissues. Results We obtained a total of 1379 DEGs with adjPval 1 including 1052 up-regulated genes and 327 down-regulated genes. 4 GO terms and 4 KEGG pathways were screened out by comparing the genomewide gene set expression patterns of normal and ulcerated tissues. 7 genes involved in RAS were identified from the VEGF signaling pathway. Conclusions Present findings demonstrated that several immune processes have a deep impact on RAS and a number of genes involved in the VEGF signaling pathway may be critical mediators or participators in the pathogenesis of RAS.

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Single-photon stimulated four wave mixing (StFWM) processes have great potential for photonic quantum information processing, compatible with optical communication technologies and integrated optoelectronics. In this paper, we demonstrate single-photon StFWM process in a piece of optical fiber, with seeded photons generated by spontaneous four wave mixing process (SpFWM). The effect of the single-photon StFWM is confirmed by time-resolved four-photon coincidence measurement and variation of four-photon coincidence counts under different seed-pump delays. According to the experiment results, the potential performance of quantum cloning machine based on the process is analyzed.