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Knowledge Graph has gradually become one of core drivers advancing the Internet and AI in recent years, while there is currently no normal knowledge graph in the field of agriculture. Named Entity Recognition (NER), one important step in constructing knowledge graphs, has become a hot topic in both academia and industry. With the help of the Bidirectional Long Short-Term Memory Network (Bi-LSTM) and Conditional Random Field (CRF) model, we introduce a method of ensemble learning, and implement a named entity recognition model ELER. Our model achieves good results for the CoNLL2003 data set, the accuracy and F1 value in the best experimental results are respectively improved by 1.37% and 0.7% when compared with the BiLSTM-CRF model. In addition, our model achieves an F1 score of 91% for the agricultural data set AgriNER2018, which proves the validity of ELER model for small agriculture sample data sets and lays a foundation for the construction of agricultural knowledge graphs.

Magnesium (Mg) and its alloys have attracted attention as potential biodegradable materials in orthopedics due to their mechanical and physical properties, which are compatible with those of human bone. However, the effect of the mismatch between the rapid material degradation and fracture healing caused by the adverse effect of hydrogen (H2), which is generated during degradation, on surrounding bone tissue has severely restricted the application of Mg and its alloys. Thus, the development of new Mg alloys to achieve ideal degradation rates, H2 evolution and mechanical properties is necessary. Herein, a novel Mg–1Zn–1Sn-xSr (x = 0, 0.2, 0.4, and 0.6 wt%) quaternary alloy was developed, and the microstructure, mechanical properties, corrosion behavior and biocompatibility in vitro/vivo were investigated. The results demonstrated that a minor amount of strontium (Sr) (0.2 wt %) enhanced the corrosion resistance and mechanical properties of Mg–1Zn–1Sn alloy through grain refinement and second phase strengthening. Simultaneously, due to the high hydrogen overpotential of tin (Sn), the H2 release of the alloys was significantly reduced. Furthermore, Sr-containing Mg–1Zn–1Sn-based alloys significantly enhanced the viability, adhesion and spreading of MC3T3-E1 cells in vitro due to their unique biological activity and the ability to spontaneously form a network structure layer with micro/nanotopography. A low corrosion rate and improved biocompatibility were also maintained in a rat subcutaneous implantation model. However, excessive Sr (>0.2 wt %) led to a microgalvanic reaction and accelerated corrosion and H2 evolution. Considering the corrosion resistance, H2 evolution, mechanical properties and biocompatibility in vitro and in vivo, Mg–1Zn–1Sn-0.2Sr alloy has tremendous potential for clinical applications., Graphical abstract Image 1, Highlights • 0.2 wt. % Sr enhances the corrosion resistance, mechanical properties and inhibits H2 evolution of Mg-1Zn-1Sn-based alloy. • Sr-containing Mg-1Zn-1Sn-based alloys have better compatibility and biological activity in vitro. • Sr-containing Mg-1Zn-1Sn-based alloys can spontaneously form a network structure layer with micro/nano topography. • Mg-1Zn-1Sn-0.2Sr exhibits excellent corrosion resistance and extremely low H2 evolution in vivo.

In recent years, as the knowledge graph has attained significant achievements in many specific fields, which has become one of the core driving forces for the development of the internet and artificial intelligence. However, there is no mature knowledge graph in the field of agriculture, so it is a great significance study on the construction technology of agricultural knowledge graph. Named entity recognition and relation extraction are key steps in the construction of knowledge graph. In this paper, based on the joint extraction model LSTM-LSTM-Bias brought in BERT pre-training language model to proposed a agricultural entity relationship joint extraction model BERT-BILSTM-LSTM which is applied to the standard data set NYT and self-built agricultural data set AgriRelation. Experimental results showed that the model can effectively extracted the relationship between agricultural entities and entities.

Polymer electrolytes (PEs) have attracted tremendous research interest for their potential to offer improved safety and energy capacity in next-generation battery technologies. Among the different classes of PEs, single-ion conductors (SICs) are particularly interesting due to their high transference numbers. Nevertheless, a detailed understanding of how molecular structure impacts the properties of SIC-PEs is absent, limiting the ability to design improved materials. Here, we present the synthesis and characterization of a new class (seven examples provided) of polyanions featuring fluorinated aryl sulfonimide tagged (FAST) anions as side chains. These "polyFAST"salts are shown to outperform the widely used poly[(4-styrenesulfonyl) (trifluoromethanesulfonyl)imide] due to their strongly electron-withdrawing side chains and enhanced distance between anionic sites, providing higher electronic conductivities at all salt concentrations and in some cases superior electrochemical oxidative stability. Moreover, they provide a platform for discovery of fundamental relationships between macromolecular composition, as programmed through monomer structure, and SIC-PE bulk properties. Finally, we leverage the electron-deficient nature of polyFAST salts to demonstrate a new poly(solvate ionic liquid) (polySIL) concept that offers a promising pathway toward high-performance PEO-free SIC-PEs.

A simple dual acylhydrazone-functionalized gelator (G1) has been designed and synthesized, and it was found to form a supramolecular organogel (G1-gel) in a mixed solvent of DMF-H2O. The gelator solution shows brilliant blue light upon mixing with Mg2+; this blue light can be erased by saliva or CO32-. Owing to this characteristic, a smart erasable writable material was prepared.

The video request service of users in 5G network will explode, and adaptive bit rate technology can provide users with reliable video response. Placing video resources on edge servers close to users can overcome the problem of excessive network load similar to traditional centralized cloud platform solutions. Moreover, multiple edge servers can provide caching and transcoding support by collaboration mechanisms, which further improves users’ Quality of Experience (QoE). However, the design difficulty of video caching and content distribution strategies is increased due to the diversity of collaboration mechanisms and the competition between local and collaborative services of edge servers for computing and storage resources. In order to solve this problem, video cache and content distribution problem is modeled as random integer programming problem in the multi-edge server at most two-hop collaboration scenario. In order to improve the security of video data transmission, the video stream is encrypted using an encryption algorithm based on Logistic chaotic-Quantum-dot Cellular Automata (QCA). For improving the efficiency of solving integer programming problems, this paper uses a pyramid intelligent evolution algorithm based on optimal cooperation strategy to solve this problem. Simulation experiments show that our proposed method can obtain higher QoE value compared with several newer methods. In addition, the average access delay of proposed method is shortened by more than 27.98%, which verifies its reliability.

Writing programs for heterogeneous platforms optimized for high performance is hard since this requires the code to be tuned at a low level with architecture-specific optimizations that are most times based on fundamentally differing programming paradigms and languages. OpenVX promises to solve this issue for computer vision applications with a royalty-free industry standard that is based on a graph-execution model. Yet, the OpenVX ’ algorithm space is constrained to a small set of vision functions. This hinders accelerating computations that are not included in the standard. In this paper, we analyze OpenVX vision functions to find an orthogonal set of computational abstractions. Based on these abstractions, we couple an existing domain-specific language (DSL) back end to the OpenVX environment and provide language constructs to the programmer for the definition of user-defined nodes. In this way, we enable optimizations that are not possible to detect with OpenVX graph implementations using the standard computer vision functions. These optimizations can double the throughput on an Nvidia GTX GPU and decrease the resource usage of a Xilinx Zynq FPGA by 50% for our benchmarks. Finally, we show that our proposed compiler framework, called HipaccVX, can achieve better results than the state-of-the-art approaches Nvidia VisionWorks and Halide-HLS.

CsPbCl3:Mn2+ is a practical solution for obtaining red-orange light inorganic perovskite nanocrystals since CsPbI3 is unstable. Increasing the concentration of Mn2+ is an effective way to enhance the orange-red emission of CsPbCl3:Mn2+. However, the relationship between emission intensity of the Mn2+ dopant and the concentration of Mn2+ is very chaotic in different studies. As a transition metal ion, the electronic states of Mn2+ are very sensitive to the crystal field environment. Here, the crystal field of the CsPbCl3:Mn2+ nanocrystals was adjusted by co-doping other cations, and the concentration of Mn2+ remained unchanged. Additionally, the crystal field strength of different samples was calculated. Compared with the CsPbCl3:Mn2+ nanocrystals, the red-orange peak in the fluorescence spectrum of CsPbCl3:Mn2+, Er3+ nanocrystals was redshifted from 580 to 600 nm and enhanced by 100 times successfully. The same experiment was carried out on CsPbCl3:Mn2+ nanoplatelets at the same time to confirm the changed crystal field around Mn2+. The effect of co-doping cations on the luminescence properties of Mn2+ is similar to that in nanocubes, and the mechanism was analyzed in detail.

To meet the growing demand for antibacterial implants for bone-implant-associated infection therapy and avoid the adverse effects of secondary surgery, a degradable platform with pH responsiveness and ion-associated antibacterial properties was constructed. A small amount of Sn added to Mg-1Zn alloy reduces the biocorrosion rate, which can be attributed to Sn participation in outer-layer film formation, significantly reducing the biocorrosion rate and hydrogen evolution rate after implantation in vivo. These Mg alloys, which are susceptible to degradation in the acidic bacterial microenvironment, degrade by releasing Mg, Zn and Sn, producing favorably alkaline and antibacterial conditions. Samples with the composition of Mg-1Zn-0.5Sn were found to be beneficial for promoting initial cell adhesion and proliferation, resulting in improved biocompatibility and biosafety. The biocompatibility of this alloy was confirmed by the healthy behavior of animals and the absence of acute or chronic toxicity in the liver, spleen, and kidneys. Our results demonstrate that Mg-1Zn-0.5Sn is safe for biological systems, enabling its efficacious use in biomedical applications.

Mixed halide perovskite is essential to construct highly efficient tandem solar cells, whereas halide segregation is a main issue hindering their device efficiency for this kind of perovskite materials. Herein, we modify the solvents for the mixed halide precursor solution to suppress halide segregation during fabrication process. An alternative solvent, N-Methyl pyrrolidone (NMP), is used to replace commonly used solvent, dimethyl sulfoxide (DMSO). It is shown that the halide segregation and the resultant carrier recombination are notably suppressed. The improvements brought by NMP may correlate with its moderate Lewis base property, which modifies the crystallization process of the mixed halide perovskite film. Consequently, the device performance is greatly improved by using NMP. The device efficiency is increased from less than 10% for DMSO solvent to approach 14% for NMP solvent. This work provides a facile way to improve the device efficiency, which also highlights on the importance of the solvents on halide segregation.

The utilization of mixed cations is beneficial for taking the advantages of cations and achieving highly efficient perovskite solar cells (PSCs). Herein, the precisely small incorporation of CH(NH2)2 (FA) cations in methyl ammonium lead iodide (MAPbI3) enables the formation of compact, smooth perovskite film with high crystallinity. Consequently, the short-circuit current and the fill factor of the PSCs based on FAxMA1-xPbI3 perovskite are greatly improved, leading to the enhanced device efficiency. The champion PSC based on FA0.1MA0.9PbI3 exhibits a remarkably high efficiency of 22.02%. Furthermore, the PSCs based on FA0.1MA0.9PbI3 perovskite also show improved device stability. This work provides a simple approach to fabricate high-quality perovskite films and high-performance PSCs with better stability.

Lead halide perovskite materials are popular in optoelectronic applications due to their excellent properties, while their instability is still a bottleneck for their potential application. In this work, sodium yttrium fluoride (NaYF4) and zinc oxide (ZnO) were used as capsules to protect CsPbBr3 nanocrystals, greatly enhancing the resistance of CsPbBr3 nanocrystals to water and polar solvents. Water-resistant and stable luminescent CsPbBr3@NaYF4 and CsPbBr3@ZnO nanocrystals were obtained by using a simple solution-phase method. These water-stable enhanced perovskite nanocrystals are suitable for long-term stable optoelectronic applications in the atmosphere.

Two-dimensional (2D) Ruddlesden–Popper perovskites (RPPs), with the general formula (RNH3)2An−1BnX3n+1, could realize promising device stability as compared with their three-dimensional counterparts. However, the power conversion efficiency (PCE) of perovskite solar cells (PSCs) with 2D RPPs is relatively low, especially the open circuit voltage (VOC) despite the large band gap of 2D RPPs. Herein, to reduce the VOC losses and enhance the PCE, we propose the use of synergetic organic spacer cations with n-butylammonium (BA+, CH3(CH2)3NH3+) as the major spacer cation and octylammonium (OA+, CH3(CH3)7NH3+) as the additive spacer cation. Scanning electron microscopy reveals that 2D RPP films with mixed organic spacer cations (with a 2 : 0.03 molar ratio of BA : OA in precursor solution) are more uniform and denser. Furthermore, it is found that the 2D RPPs with OA cations exhibit enhanced charge transport by suppressing low-n phases, which is beneficial for high VOC. With the assistance of the OA spacer cation, the VOC is notably increased from 0.94 V to approximately 1.1 V. PSCs with BA–OA 2D RPP achieve the highest PCE of 11.90%, which is higher than that based on pure BA 2D RPP (10.81%). The unencapsulated devices with BA–OA 2D RPPs retain 63% and 93% of their original PCE after being kept in air with a humidity of 30% ± 5% at a room temperature of 20 °C ± 5 °C for 410 h and in a N2 glove box over 1224 h, respectively. This work provides a simple idea for achieving high quality 2D RPP films, and highlights the importance of organic spacer cations in obtaining highly performed PSCs.

Although reported ternary polymer solar cells have higher power conversion efficiency than binary polymers, the mechanism of exciton separation and charge transport in this complex ternary system is still unclear. Herein, based on PM6:Y6:ITIC-M ternary solar cells, we combine the technique of luminescence spectroscopy, including electroluminescence (EL) and photoluminescence (PL) with photovoltaic measurements, to understand clearly the detailed roles of ITIC-M as the third component in the contribution of device performance. The results show that ITIC-M can form the alloy-like composite with Y6 but leave individual Y6 acceptor to conduct charge transfer with PM6 donor, which improves Voc but decreases Jsc because of poor charge transfer capacity of ITIC-M. Meanwhile, the energy transfer from PM6 to ITIC-M exists in the active layers, small IE suppresses exciton dissociation. Deteriorating performance of solar cells demonstrates that, except for complementary absorption spectrum and suitable energy levels in PM6:Y6:ITIC-M system, the synergetic effects of carrier dynamics among different organic materials play an important role in influencing the performance of ternary solar cells.

Phosphorescent organic light-emitting diodes (PhOLEDs) are a kind of highly efficient and solution-processable devices for displays and light sources, which employ phosphorescent material as the gu...

Inefficient blue emission is one of the key bottlenecks limiting the development of solution processable displays and white light sources, which is essentially governed by the film quality of the solution-processed emission layer (EML). Here, we use an efficient blue thermally activated delayed fluorescent (TADF) emitter, bis [4-(9,9-dimethyl-9,10-dihydroacridine)phenyl]solfone (DMAC-DPS), as EML and propose a solvent engineering strategy to achieve high efficiency and brightness. The strategy employs synergetic solvents to improve the film morphology of the solution-processed DMAC-DPS EML. The improved film quality enhances the carrier injection while reduces the surface trap charges, as revealed by the hole-/electron-only device performance and the transient electroluminescence measurements. As expected, the blue organic light-emitting devices (OLEDs) employing synergetic solvent strategy presents an increment of 22.8% in efficiency and 19.4% in luminescence, which reaches the highest efficiency of 15.76 cd/A and an efficiency of 9.63 cd/A at a luminance of 1000 cd/m2. These values are generally higher than the reported values from the blue OLEDs based on solution-processed DMAC-DPS EML.

Solution processed blue phosphorescent organic devices based on mixed host system were fabricated in this paper. A set of blue phosphorescent organic light emitting diodes (PhOLEDs) utilizing two small molecular materials of 3,3-Di(9H-carbazol-9-yl) biphenyl (mCBP) and 4,4′,4′′-tris(N-carbazolyl)-triphenylamine (TCTA) as mixed host doped with phosphor bis[(4,6-difluorophenyl)-pyridina-to-N,C2](picolinate) iridium(III) (FIrpic) are fabricated. The results show that the performance of mixed host system devices is improved compared with two single host devices. The max luminance of 23,340 cd/m2 is achieved in the mCBP:TCTA (2:1) mixed host device while the 14,400 cd/m2 in mCBP single host devices and the 12,968 cd/m2 in TCTA, and the current efficiency is improved from 8.17 cd/A(mCBP), 9.61 cd/A (TCTA) to 13.62 cd/A at the luminance of 1000 cd/m2. The transient electroluminescence measurement was utilized to detect the carrier injection between two kinds of PhOLEDs and penetrate how the trap charges works in the mixed host devices. This presents that the mixed host system contributes to the hole injection and the equilibrium of the carrier transport, reduces trapped charges, thus brings about high efficiency devices.

We demonstrate solution-processed inverted polymer light-emitting diodes (PLEDs) using a yellow emitting copolymer “Super Yellow” (SY). The PLEDs exhibit high performance with a luminance above 17000 cd m−2 at 8 V and a maximum external quantum efficiency (EQE) of 4.1%, which is higher than its theoretical limit. We investigate the dynamic properties of polymeric excitons upon both photo- and electro-excitation. The results give an overview of the fundamental dynamic of monomolecular excitons, suggesting that the extra high EQE could be attributed to the generating of more than 25% prompt singlet excitons other than the bimolecular processes such as triplet-triplet annihilation(TTA). Furthermore, by extending the exciton formation zone and tuning the charge distribution inside the devices, dominated process in the exciton quenching, which is the main reason for the efficiency roll-off under high current density, is confirmed to be polaron-exciton quenching process.

In order to utilize the leaked electrons from emission layer (EML) and simultaneously enhance the performance of the quantum dot light-emitting diodes (QLEDs), a blue thermally activated delayed fluorescence (TADF) material, 10,10'-(4,4-Sulfonylbis(4,1-phenylene))bis(9,9-dimethyl-9,10-dihydroacridine) (DMAC-DPS), was inserted as an interlayer between hole transport layer (HTL) and quantum dot (QD) EML. In the TADF inserting layer, the leaked electrons from the EML can form excitons with the injected holes from the HTL, followed by energy transfer from the TADF material to the QD EML. The TADF inserting layer is also expected to promote the hole injection from HTL to EML and to alleviate the electron accumulation situation at QD/HTL interface. Therefore, compared with standard QLED without TADF inserting layer, the utilization of electrons in the QLEDs with TADF interlayer are enhanced and the charge carriers are more balance in QD EML. These benefits enable a 1.17-fold increment for current efficiency (from 8.9 cd/A to 10.44 cd/A) and 1.41-fold improvement for maximum luminance (from 44781 cd/m2 to 63458 cd/m2) in the optimal QLED employing 5 nm TADF interlayer.

BACKGROUND: Nano-hydroxyapatite/polyamide 66 (nHA/PA66) is a composite used widely in the repair of bone defects. However, this material is insufficient bioactivity. In contrast, D-RADA16-RGD self-assembling peptide (D-RADA16-RGD sequence containing all D-amino acids is Ac-RADARADARADARADARGDS-CONH(2)) shows admirable bioactivity for both cell culture and bone regeneration. Here, we describe the fabrication of a favorable biomaterial material (nHA/PA66/D-RADA16-RGD). METHODS: Proteinase K and circular dichroism spectroscopy were employed to test the stability and secondary structural properties of peptide D-RADA16-RGD respectively. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to characterize the surface of these materials. Confocal laser scanning (CLS), cell counting kit-8 tests (CCK-8), alizarin red S staining, cell immunofluorescence analysis and Western blotting were involved in vitro. Also biosafety and bioactivity of them have been evaluated in vivo. RESULTS: Proteinase K and circular dichroism spectroscopy demonstrated that D-RADA16-RGD in nHA/PA66 was able to form stable-sheet secondary structure. SEM and TEM showed that the D-RADA16-RGD material was 7–33 nm in width and 130–600 nm in length, and the interwoven pore size ranged from 40 to 200 nm. CLS suggests that cells in nHA/PA66/D-RADA16-RGD group were linked to adjacent cells with more actin filaments. CCK-8 analysis showed that nHA/PA66/D-RADA16-RGD revealed good biocompatibility. The results of Alizarin-red S staining and Western blotting as well as vivo osteogenesis suggest nHA/PA66/D-RADA16-RGD exhibits better bioactivity. CONCLUSION: This study demonstrates that our nHA/PA66/D-RADA16-RGD composite exhibits reasonable mechanical properties, biocompatibility and bioactivity with promotion of bone formation. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s13770-018-0171-5) contains supplementary material, which is available to authorized users.

A novel high concentration doping method based on the transformation from Cs4PbBr6 nanocrystals (NCs), which reacted with divalent metal bromide MBr2, to CsPbxM1−xBr3 NCs was developed. Two types of M2+ and Zn2+ which cannot emit light and Mn2+ and Eu2+ which can be used as the luminous centres, were chosen to trigger the transformation of Cs4PbBr6 NCs to CsPbxM1−xBr3 NCs. CsPbxZn1−xBr3 NCs maintained high photoluminescence quantum yields (PLQY) (>75%) and had good dispersion in hexane without obvious dissolution or agglomeration after two weeks. By adjusting the reaction temperature, the intrinsic band edge luminescence and the emission of Mn2+ ions CsPbxMn1−xBr3 NCs show different colours of light from green, green-yellow, pink, and orange-red to purple under an excitation of 365 nm. CsPbxEu1−xBr3 NCs were synthesized for the first time, and a weak luminescence around 618 nm from Eu3+ was detected in addition to the band edge luminescence of NCs. X-ray photoelectron spectroscopy (XPS) data showed that Zn2+, Mn2+ and Eu3+ (Eu2+) doping concentrations are up to 80%, 75% and 50%, respectively. We also analysed the doping mechanism and compared the new method with the traditional high temperature injection method. The lead-depleted perovskite NCs transformed from Cs4PbBr6 can provide a feasible pathway to reduce the lead toxicity of perovskite NCs and expand their applications.

The noise-shaping successive approximation register (NS-SAR) analog-to-digital converter (ADC) is an emerging hybrid architecture that achieves high resolution and power efficiency simultaneously by combining the merits of the SAR ADC and the $\Delta \Sigma $ ADC. Most prior works adopting the cascaded integrator feed-forward (CIFF) structure demonstrate inefficiency in realizing optimized noise transfer function (NTF). This paper presents a second-order NS-SAR ADC employing the error-feedback (EF) structure to realize complex NTF zeros for noise-shaping enhancement with the minimum modification to a standard SAR. It implements a low-power scaling-friendly EF path by using a passive finite impulse response (FIR) and a comparator-reused dynamic amplifier with process-voltage-temperature (PVT) tracking background calibration. Fabricated in 40-nm CMOS, the prototype chip consumes $84~\mu \text{W}$ when operating at 10 MS/s. The NS-SAR achieves peak Schreier FoM of 178 dB with 79-dB signal to noise and distortion ratio (SNDR) at an oversampling ratio (OSR) of 8.

With the rapid deployment of cloud platforms, high service reliability is of critical importance. An industrial cloud platform contains a huge number of disks, and disk failure is a common cause of service unreliability. In recent years, many machine learning based disk failure prediction approaches have been proposed, and they can predict disk failures based on disk status data before the failures actually happen. In this way, proactive actions can be taken in advance to improve service reliability. However, existing approaches treat each disk individually and do not explore the influence of the neighboring disks. In this paper, we propose Neighborhood-Temporal Attention Model (NTAM), a novel deep learning based approach to disk failure prediction. When predicting whether or not a disk will fail in near future, NTAM is a novel approach that not only utilizes a disk’s own status data, but also considers its neighbors’ status data. Moreover, NTAM includes a novel attention-based temporal component to capture the temporal nature of the disk status data. Besides, we propose a data enhancement method, called Temporal Progressive Sampling (TPS), to handle the extreme data imbalance issue. We evaluate NTAM on a public dataset as well as two industrial datasets collected from millions of disks in Microsoft Azure. Our experimental results show that NTAM significantly outperforms state-of-the-art competitors. Also, our empirical evaluations indicate the effectiveness of the neighborhood-ware component and the temporal component underlying NTAM as well as the effectiveness of TPS. More encouragingly, we have successfully applied NTAM and TPS to Microsoft cloud platforms (including Microsoft Azure and Microsoft 365) and obtained benefits in industrial practice.

Deep-red organic light-emitting diodes (DR-OLEDs) or near-infrared organic light-emitting diodes (NIR-OLEDs) have a wide range of applications in real life, such as special light sources for plant growth in agriculture, optical communications, infrared imaging, infrared medical imaging and other fields. However, the device performance of DR-OLEDs is still far behind that of red, green and blue OLEDs. In addition to the well-known energy gap law, the location of the recombination region also has a significant impact on the device performance. If the recombination area is too close to the cathode, the electrons in the electron transport layer will easily cause exciton quenching. In this study, for the first time, we adopted a quantum well-like structure by changing the host (CBP) and guest (TPA-DCPP) thicknesses as the light-emitting layer to manage the position of the recombination zone, and then improved the carrier injection and transportation as well as increased the exciton recombination rate. Furthermore, we introduced a hole trap layer to reduce the current density and suppress the recombination zone movement; finally, we prepared high-brightness and high-efficiency DR-OLEDs based on the TADF material with a wavelength of 674 nm, a maximum brightness of 1151 cd m−2 and a maximum EQE of 4.4%.

In cloud service systems, customers will report the service issues they have encountered to cloud service providers. Despite many issues can be handled by the support team, sometimes the customer issues can not be easily solved, thus raising customer incidents. Quick troubleshooting of a customer incident is critical. To this end, a customer incident should be assigned to its responsible team accurately in a timely manner. Our industrial experiences show that linking customer incidents with detected system incidents can help the customer incident triage. In particular, our empirical study on 7 real cloud service systems shows that with the additional information about the system incidents (i.e., incident reports generated by system monitors), the triage time of customer incidents can be accelerated 13.1× on average. Based on this observation, in this paper, we propose LinkCM, a learning based approach to automatically link customer incidents to monitor reported system incidents. LinkCM incorporates a novel learning-based model that effectively extracts related information from two resources, and a transfer learning strategy is proposed to help LinkCM achieve better performance without huge amount of data. The experimental results indicate that LinkCM is able to achieve accurate link prediction. Furthermore, case studies are presented to demonstrate how LinkCM can help the customer incident triage procedure in real production cloud service systems.

The management of cloud service incidents (unplanned interruptions or outages of a service/product) greatly affects customer satisfaction and business revenue. After years of efforts, cloud enterprises are able to solve most incidents automatically and timely. However, in practice, we still observe critical service incidents that occurred in an unexpected manner and orchestrated diagnosis workflow failed to mitigate them. In order to accelerate the understanding of unprecedented incidents and provide actionable recommendations, modern incident management system employs the strategy of AIOps (Artificial Intelligence for IT Operations). In this paper, to provide a broad view of industrial incident management and understand the modern incident management system, we conduct a comprehensive empirical study spanning over two years of incident management practices at Microsoft. Particularly, we identify two critical challenges (namely, incomplete service/resource dependencies and imprecise resource health assessment) and investigate the underlying reasons from the perspective of cloud system design and operations. We also present IcM BRAIN, our AIOps framework towards intelligent incident management, and show its practical benefits conveyed to the cloud services of Microsoft.

In large-scale cloud systems, unplanned service interruptions and outages may cause severe degradation of service availability. Such incidents can occur in a bursty manner, which will deteriorate user satisfaction. Identifying incidents rapidly and accurately is critical to the operation and maintenance of a cloud system. In industrial practice, incidents are typically detected through analyzing the issue reports, which are generated over time by monitoring cloud services. Identifying incidents in a large number of issue reports is quite challenging. An issue report is typically multi-dimensional: it has many categorical attributes. It is difficult to identify a specific attribute combination that indicates an incident. Existing methods generally rely on pruning-based search, which is time-consuming given high-dimensional data, thus not practical to incident detection in large-scale cloud systems. In this paper, we propose MID (Multi-dimensional Incident Detection), a novel framework for identifying incidents from large-amount, multi-dimensional issue reports effectively and efficiently. Key to the MID design is encoding the problem into a combinatorial optimization problem. Then a specific-tailored meta-heuristic search method is designed, which can rapidly identify attribute combinations that indicate incidents. We evaluate MID with extensive experiments using both synthetic data and real-world data collected from a large-scale production cloud system. The experimental results show that MID significantly outperforms the current state-of-the-art methods in terms of effectiveness and efficiency. Additionally, MID has been successfully applied to Microsoft's cloud systems and helped greatly reduce manual maintenance effort.

Summary Fluorescence is critical to applications in optical materials including OLEDs and photonics. While fluorescent dyes are potential key components of these materials, electronic coupling between them in the solid state quenches their emission, preventing their reliable translation to applications. We report a universal solution to this long-standing problem with the discovery of a class of materials called small-molecule ionic isolation lattices (SMILES). SMILES perfectly transfer the optical properties of dyes to solids, are simple to make by mixing cationic dyes with anion-binding cyanostar macrocycles, and work with major classes of commercial dyes, including xanthenes, oxazines, styryls, cyanines, and trianguleniums. Dyes are decoupled spatially and electronically in the lattice by using cyanostar with its wide band gap. Toward applications, SMILES crystals have the highest known brightness per volume and solve concentration quenching to impart fluorescence to commercial polymers. SMILES materials enable predictable fluorophore crystallization to fulfill the promise of optical materials by design.

CUDA graph is an asynchronous task-graph programming model recently released by Nvidia. It encapsulates application workflows in a graph, with nodes being operations connected by dependencies. The new API brings two benefits: Reduced work launch overhead and whole workflow optimizations. In this paper, we improve the ability of CUDA graph to exploit workflow optimizations, e.g., concurrent kernel executions with complementary resource occupancy. Additionally, we argue that the advantages of DSLs are complementary to CUDA graph, and joining the two techniques can benefit from the best of both worlds. Here, we propose a compiler-based approach that combines CUDA graph with an image processing DSL and a source-to-source compiler called Hipacc. For ten image processing applications benchmarked on two Nvidia GPUs, our approach is able to achieve a geometric mean speedup of 1.30 over Hipacc without CUDA graph, 1.11 over CUDA graph without Hipacc, and 3.96 over another state-of-the-art DSL called Halide.

Hipacc is a domain-specific language for ease of programming image processing applications on hardware accelerators such as GPUs. It relieves the burden of manually porting algorithms to hardware for developers with the help of domain- and architecture-specific knowledge. One fundamental operation in image processing is reduction. Global reduction operators are the building blocks of many widely used algorithms, including image normalization, similarity estimation, etc. This paper presents an efficient approach to perform parallel reductions on GPUs with Hipacc. Our proposed approach benefits from the continuous effort of performance and programmability improvement by hardware vendors, for example, by utilizing the latest low-level primitives from Nvidia. Results show our approach achieves a speedup of up to 3.43 over an existing Hipacc implementation with traditional optimization methods, and a speedup of up to 9.02 over an implementation using the Thrust library from Nvidia.

Multiresolution filters, analyzing information at different scales, are crucial for many applications in digital image processing. The different space and time complexity at distinct scales in the unique pyramidal structure poses a challenge as well as an opportunity to implementations on modern accelerators such as GPUs with an increasing number of compute units. In this paper, we exploit the potential of concurrent kernel execution in multiresolution filters. As a major contribution, we present a model-based approach for performance analysis of as well single- as multi-stream implementations, combining both application- and architecture-specific knowledge. As a second contribution, the involved transformations and code generators using CUDA streams on Nvidia GPUs have been integrated into a compiler-based approach using an image processing DSL called Hipacc. We then apply our approach to evaluate and compare the achieved performance for four real-world applications on three GPUs. The results show that our method can achieve a geometric mean speedup of up to 2.5 over the original Hipacc implementation without our approach, up to 2.0 over the other state-of-the-art DSL Halide, and up to 1.3 over the recently released programming model CUDA Graph from Nvidia.

Yanan Xu,1 Hong Li,2 Jieming Wu,3 Qiming Yang,1 Dianming Jiang,4 Bo Qiao1 1Department of Orthopedics, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China; 2Research Center for Nano-Biomaterials, Analytical and Testing Center, Sichuan University, Chengdu, People’s Republic of China; 3Office of Teaching Affairs, The First Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China; 4Department of Orthopedics, The Third Affiliated Hospital of Chongqing Medical University, Chongqing, People’s Republic of China Background: Hydroxyapatite/polyamide 66 (HA/P66) has been clinically used for several years owing to its good biocompatibility and bioactivity. However, it has been found that the osseointegration process of the HA/P66 implant takes a large amount of time because of the small amount of HA on its surface.Methods: To increase the amount of HA and aid faster osseointegration, we prepared a HA coating using a biomimetic process assisted by polydopamine (PDA) on the HA/P66 substrate. The surface properties of the substrate modified by PDA and HA were characterized, and the capacity of biomaterials for osteogenic induction was investigated both in vitro and in vivo. Results: The HA coating was successfully prepared on the HA/P66 substrate and verified by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), and X-ray diffraction (XRD). The HA coating remained firmly attached to the underlying PDA-HA/P66 substrate even after strong ultrasound treatment for 1 h, and the calcium and phosphorus of the HA coating was continuously released in vitro in a slow manner. The formation of the HA coating on the PDA film greatly increased the hydrophilicity and surface roughness of HA/P66. In cell-based experiments, as compared with the HA/P66 substrate, the HA coating formation on the PDA film could facilitate the functions of C3H10T1/2 cells, including cell adhesion, proliferation, spreading, alkaline phosphatase activity, calcium nodule formation, and expression of osteogenic differentiation-related proteins. In addition, the HA/P66 scaffolds modified with PDA and HA coatings were implanted in rabbit femoral condyles. At 8 weeks after surgery, micro-computed tomography scanning (micro-CT) and hematoxylin–eosin (HE) staining revealed that more new bones were formed around the HA/P66 scaffold that was modified with a PDA-assisted HA coating. Conclusion: These results indicate that the preparation of a PDA-assisted HA coating by using a biomimetic process significantly improves the capacity of biomaterials for osteogenic induction. Keywords: hydroxyapatite, polydopamine, hydroxyapatite/polyamide 66, surface modification, osteogenic induction

A new near-infrared-responsive photocatalyst of NaYF4:Yb,Tm@Cu2O have been successfully synthesized by a simple method. Methylene blue as a model pollutant was used to study the photocatalytic activity of NaYF4:Yb,Tm@Cu2O composites, and the energy transfer process between NaYF4:Yb, Tm and Cu2O and the origin of the degradation of pollutants were investigated. It was found that the energy transfer route between NaYF4:Yb, Tm and Cu2O is an important factor for the overall photocatalytic activity. This study suggests a promising system to apply upconversion materials for utilizing the near-infrared light to irradiate Cu2O-based photocatalysts.

Even though all-inorganic lead halide perovskite (CsPbX3; X = Cl, Br, I) quantum dots (QDs) with great optoelectronic properties such as high fluorescence quantum yield, facile colour tunability, and high colour purity have been under the spotlight in recent years, their poor stability makes their application in LEDs difficult. In comparison to CsPbBr3 QDs that display green emission, CsPbCl3 QDs with blue light emission contain more defects in the material and exhibit lower fluorescence quantum yield and device service time, which is the bottleneck in realizing blue, green, and red three-base coloured perovskite QD-based LEDs. It is therefore a pressing issue to develop other techniques instead of anion exchange to adjust the light emission of CsPbX3 and simultaneously enhance the stability of the nanocrystals, especially for blue emission. In this work, CsPbBr3 QDs compounded with CsPb2Br5 (CsPbBr3-CsPb2Br5 QDs) with stable blue and green emissions are obtained using improved one-step solution-phase method. CsPb2Br5 can enhance the luminescent colour and structural stability of CsPbBr3 QDs. CsPbBr3-CsPb2Br5 QDs showed greater stability than pure CsPbBr3 QDs in various environments. Moreover, CsPbBr3-CsPb2Br5 QDs are smaller than CsPbBr3 QDs synthesized at the same temperature, which results in blue-shift of the photoluminescence spectra. Owing to the strong stability, their photoluminescence emission peak can be simply and reliably tuned continuously between 480 nm and 520 nm through the reaction temperature.

It is a significant trend that the Internet Content Providers (ICPs) improve the quality of service and reduce the cost of content distribution by the Content Delivery Networks (CDNs). In order to spend the less money to get better services, ICPs need to find a lot of information about CDNs, such as server deployment, performance, price and so on, to determine whether CDN services satisfy their requirements. Unfortunately, these information can’t be obtained by third party due to business secret. ICPs still choose CDNs on the basis of one-sided viewpoint. For this reason, we have proposed a data-driven and the deep learning based CDN recommendation framework for ICPs. The contributions lie in: 1) A three-tier CDN recommendation framework is presented to achieve data-driven and the deep learning based recommendation service. 2) A CDN recommendation model is built based on the deep neural network, which improves the efficiency of the recommendation service and satisfies the personalized demand. 3) A prototype system is developed and deployed on the real-world large-scale Internet in China. Experimental results demonstrate that the correctness of the recommendation results is up to 91%, and degree of satisfaction reached 80%.

Exciplex states play a crucial role in governing the ultimate device performance, as both current density-voltage-luminescence characteristics and external quantum efficiency directly depend on it. For electron-hole evolution, exciplex states represent the intermediate but essential step between exciton recombination and dissociation. Therefore, the fundamental understanding of the processes involving the exciplex state is essential for utilizing such mediate state to achieve high emission efficiencies approaching the theoretical limits with simple structured organic light-emitting diodes (OLEDs). Herein, we systemically investigate the evolution of exciplex states using transient photoluminescence measurements compiling with transient electroluminescence measurements on high-performance exciplex type thermally activated delayed fluorescence (TADF) OLEDs. The dynamic properties of the long-lived fluorescent exciplex states upon both photo-excitation and electro-excitation offer in-depth insight to the fundamental mechanisms driving its decay pathways, and by studying the electric-field dependent motion of exciplex, we can explore its transport and emission evolution.

In polymer solar cells (PSCs) which are typically processed from solution, the molecules inside the active layer accumulate disorderly, which greatly hinders the exciton dissociation and carrier transport, especially in thick active layers. Here, we propose an effective and simple strategy to solve such problem in poly [(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3‴-di (2-octyldodecyl) 2,2’; 5′,2’’; 5″,2‴-quaterthiophen-5,5‴-diyl)] (PffBT4T-2OD) polymer based thick active layer by regulating the polymer crystallize behavior via incorporating two synergistic additives diphenylether (DPE) and 1-chloronaphthalene (CN) during the film processing. The as-prepared active layer enables the PSC exhibiting a remarkable high photoelectric conversion efficiency of 10.93%, which is much higher than the standard PSC fabricated without additives under the same conditions (9.05%) or with single additive. The high PCE of the PSCs is a result of the highly ordered molecular packing and the formation of three-dimensional charge transport channels of the polymer donor. It is evidenced that the microstructure of the active layer treated simultaneously with DPE and CN undergoes a double change in the orderly stacking of the alkyl chain and the π-π bond, which is more favorable for the charge transport. The results indicate that the active layer with two synergistic additives can be used as an effective and convenient method for controlling the film morphology in the polymer solar cells.

The power conversion efficiencies (PCEs) of potential polymer solar cells have been shown to rapidly exceed 15%. However, these high-performance devices are based on halogenated solvents that pose a significant hazard to the atmospheric environment and human beings. The use of nonhalogenated solvents makes the device less efficient because of its solubility issues. In this work, we report high-efficiency devices utilizing PffBT4T-2OD and [6,6]-phenyl C71 butyric acid methyl ester system from nonhalogenated solvents such as o-xylene (o-XY) and 1-methylnaphthalene (Me) hydrocarbon solvent. When Me was used as the additive, the PCE of prepared devices improved from 1.83 to 10.13%, which is rather higher than that of the devices processed with traditional solvents combined with chlorobenzene and 1,8-diiodooctane (8.18%). Both atomic force microscopy and transmission electron microscopy confirmed that after nonhalogen solvents are treated, a more finely phase-separated dense morphology of active layers than af...

A placer without considering modern technology and region constraints could generate solutions with irresolvable detailed-routing (DR) violations or even illegal solutions. This paper presents a high-quality placement algorithm to satisfy technology and region constraints and optimize DR routability with five major techniques: 1) a clustering algorithm followed by two-round quadratic placement to obtain an initial placement satisfying region constraints; 2) a novel density control technique to handle prefixed architectures and minimize global routing congestions; 3) an analytical placement algorithm with new wirelength and density models to consider region constraints; 4) a dynamic penalty increment strategy that reduces wirelength increments during global placement; and 5) a legalization algorithm that preserves the solution quality of global placement while satisfying technology and region constraints. Compared with the winning teams of the ISPD 2015 Blockage-Aware Detailed Routing-Driven Placement Contest and recent works, our placer achieves the best overall score and DR results.

The grain size of perovskite films is a key factor to optimize the performance of perovskite photovoltaic devices. Herein, a new route is developed in this paper to prepare CH3NH3PbI3 (MAPbI3) films with a better morphology and crystallization. This method includes the spin coating deposition of perovskite films with a precursor solution of PbI2 and CH3NH3I at the molar ratio 1 : 1 and thermal annealing (TA). The thermal annealing is conducted with a thermal-induced process to realize grain growth with solvent evaporation. In addition, a mixed solvent vapor treatment in acetic acid with chlorobenzene (HAc/CB) improves the morphology and crystallization of films further. As a result, the photovoltaic device based on the perovskite film treated by mixed HAc/CB solvent exhibits the best efficiency of 13.15% in comparison to the control device with 11.44% under AM 1.5G irradiation (100 mW cm−2).

The ternary solar cell has been proved as an elegant strategy to realize efficient bulk heterojunction (BHJ) organic solar cells (OSCs) by harvesting a larger range of photons than binary devices. In order to design such an efficient system, the charge carrier transport and recombination in ternary OPVs must be considered. We fabricated various ternary devices by adding squaraine derivatives (SQ-1, SQ-2, SQ-3, SQ-4 and SQ-5) with complementary absorption spectrum in near infrared region as the additional donor material into Poly [[9-(1-octylnonyl)-9H-carbazole-2, 7-diyl]-2, 5-thiophenediyl-2, 1, 3-benzothiadiazole-4, 7-diyl-2, 5-thiophenediyl] (PCDTBT): [6,6]-phenyl C71 butyric acid methyl ester (PC71BM) host binary blend film in this paper. Through the charge carrier mobility and transient photovoltage (TPV) measurements, it is found that the incorporation of 10% SQ-5 with shallower Highest Occupied Molecular Orbital (HOMO) level hinders holes in transferring from SQ to PCDTBT, which leads to unbalanced charge carrier transport, significant charge recombination, and decrease of performance. On the contrary, the performance of ternary devices incorporated with 10% SQ-3 with deeper HOMO energy level is improved by 21% compared with binary devices, which can be attributed to increased photon harvesting and changeless charge carrier characteristics.

Solution-processed blue quantum dot light-emitting diodes (QLEDs) suffer from low device efficiency, whereas the balance of electron and hole injection is critical for obtaining high efficiency. Herein, synergistical double hole transport layers (D-HTLs) are employed, which use poly(9-vinylcarbazole) (PVK) stacked on poly[(9,9-dioctylfluorenyl-2,7-diyl)-alt-(4,4'-(N-(4-butylphenyl) (TFB). The fabrication of D-HTLs is achieved by using dimethyl formamide (DMF) as the solvent for PVK, with which the underlying TFB layer almost remains unwashed and undamaged during the spin-coating process of PVK layer. TFB/PVK D-HTLs form the stepwise energy level for hole injection, which reduces the hole injection barrier and favors the carrier balance in the emission layer (EML). The optimized blue QLED with TFB/PVK D-HTLs shows a maximum external quantum efficiency (EQE) of 13.7%, which is 3-fold enhancement compared to that of the control device with single TFB HTL. The enhancement of the QLED performance can be attributed to the improvement of surface morphology and charge injection balance for the stepwise D-HTLs based QLEDs. This work manifests the positive effect on performance boost by selecting appropriate solvents towards stepwise D-HTLs formation and paves the way to fabricate highly efficient all-solution processed light emitting diodes.

CsPbX3 (X = Cl, Br, I) perovskite nanocrystals (NCs) are promising materials due to their excellent optoelectronic properties. In this work, we show a successful partial and reversible cation exchange reaction between Pb and Mn in both CsPbCl3 NCs and CsMnCl3 NCs systems to yield luminescent CsPb1–xMnxCl3 NCs. By adjusting the reaction time, the photoluminescence from the exciton emission of CsPbCl3 and the electron transition of Mn2+ can be tuned gradually. This work highlights the feasibility of a postsynthetic interconversion of Pb2+ and Mn2+ in cesium lead chloride perovskite nanocrystals, which enables a new strategy to reduce the toxicity and adjust the emissions of CsPbCl3 NCs. In the end, we also discuss the plausible mechanisms for cation exchange in perovskite materials.

The development of small molecule organic solar cells (SMOSCs) has attracted considerable attention and achieved comparable power conversion efficiency (PCE) with polymer solar cells. Here, we demonstrate a bulk heterojunction (BHJ) small molecular solar cell with PCE of 5.31% by incorporating Bisadduct of phenyl-C71-butyric acid methyl ester (Bis-PC71BM) as an additional acceptor material into the host binary blend of 2-[4-(N-butyl-N-phenylamino)-2,6-dihydroxyphenyl]-4-[(4-(N-butyl-N-phenylamino)-2,6-dihydroxyphenyl)-2,5-dien-1-ylidene]-3-oxocyclobut-1-en-1-olate (SQ-BP): [6,6]-phenyl C71 butyric acid methyl ester (PC71BM). The short circuit current (JSC) and the fill factor (FF) of ternary SMOSCs are improved by decreasing the carrier recombination loss, increasing exciton dissociation and enhancing the carrier transport. The transient photovoltage (TPV) measurement indicates that the gradient HOMO energy alignment suppresses the charge recombination and leads to the increased charge carrier lifetime in ternary SMOSCs. As a result, the PCE of ternary devices with 5 wt% Bis-PC71BM is about 20% greater than that of SQ-BP: PC71BM based binary SMOSCs.

Google proposed the concept of knowledge graph to improve the quality of searching results in 2012, so the knowledge graph brought a hot topic in the field of academic and industry. The knowledge graph can effectively improve the searching quality and the accuracy of Q & A system, which is a hot issue. With the help of agricultural experts, this paper based on the Agricultural Thesaurus, determines the rules for judging whether a thesaurus is a concept or an entity, establishes maps from Agricultural Thesaurus to the agricultural knowledge graph schema layer and the data layer. Therefore, the large-scale automatic building is realized from the Agricultural Thesaurus to the agricultural knowledge graph. In order to effectively manage and utilize triples, this paper proposes a mathematical model for the management of triples with the RDF-based triple storage pattern, which lays the solid foundation for the semantic-based agricultural information retrieving and the construction of the Q & A system.

Tetragonal rare-earth ions codoped LiScF 4 nanocrystals have been synthesized by a modified solvothermal method. The results revealed that the phase and morphology can be tailored through varying the synthesis conditions, such as reaction temperature and time. Meanwhile, the UC fluorescence emission spectra were measured. It turned out that the UC emission intensity can be significantly influenced by reaction temperature and time. Different from the NaYF 4 :20%Yb 3+ ,2%Er 3+ nanocrystals that usually emit green emission, yellow color emission can be observed in the LiScF 4 :20%Yb 3+ ,2%Er 3+ samples under 980 nm excitation, which illustrates that the obtained new phase LiScF 4 is suitable as a promising host for efficient UC fluorescence generation and tunable UC emission spectra. Moreover, the UC mechanism was investigated in detail.

AC-driven organic light-emitting diodes (OLEDs) can overcome some reliability-related drawbacks to traditional DC-OLEDs. They imply the use of insulating layers in the device. In this work OLEDs containing an insulating layer of poly (methyl methacrylate) (PMMA) in storing charges with the thickness of 2, 6, 8, 10 nm have been prepared and investigated. The emission mechanisms of the device are analyzed considering transient and AC electroluminescence (EL) measurements. We show that charges are stored in the PMMA layer as surface charges and bulk charges. The former contribute to the occurrence of EL spike after the driving pulse with a decay tail for about 80 μs to 10nm PMMA device, and the latter can be released to emit light under reversed voltage more than 2 V because they are immobile unless under the stronger reversed field. Stored charges commonly are harmful for the performance of OLEDs devices due to quenching, nonradiative transition and the thermal energy accumulation even degradation. Whereas when operating under alternating current (AC) stress, we not only obtain the EL peak from injection charges under forward voltage, but also obtain another peak below the built-in voltage 4.3 V, whose peak point lies in −0.2 V. It turns to originate from stored charges so they become beneficial instead of weakening EL for reusing to produce light. All the results pave the way to realize AC driven OLEDs devices using these stored charges, to uncover the AC EL mechanisms and to improve their EL performance.