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Electronic devices need to work at high temperature in some fields for a long time, peculiarly step soldering technology, primary packaging and flip-chip connections, etc., along with the application of electronic products more an...
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Electronic devices need to work at high temperature in some fields for a long time, peculiarly step soldering technology, primary packaging and flip-chip connections, etc., along with the application of electronic products more and more widely. These phenomena promote the further development of high-temperature solders. Because of the high melting temperatures of Sn-Ag and Sn-Sb, they are suitable for high-temperature fields such as automotive electronics and avionics. In this review, the influences of trace elements and nanoparticles on microstructure, intermetallic components (IMC) growth, mechanical properties, wettability, melting behavior, and creep behavior of Sn-Ag and Sn-Sb solders have been summarized systematically. It was found that the addition of trace elements or nanoparticles into solders to be beneficial in improving the performance of Sn-Ag and Sn-Sb solders. Besides, the melting behavior of the solder at high temperatures can be further improved if Sn-Ag and Sn-Sb are used better as high-temperature solders.
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The window and shading configuration is the weak link of heat insulation in the outer protective structure. And it is also an important means of visual performance, which plays an important part in building energy savings. Resulti...
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The window and shading configuration is the weak link of heat insulation in the outer protective structure. And it is also an important means of visual performance, which plays an important part in building energy savings. Resulting from the influence of weather and solar radiation, there are contradictions among the energy consumption, visual performance and thermal environment. Therefore, in order to optimize the three factors, an effective optimization method is necessary. For the window design, the existing studies mostly focus on the analysis of energy consumption performance, less on the sound insulation performance. In addition, the optimal configuration of windows and shading system under different climatic regions and orientations has been solved. In this paper, a multi-objective optimization model considering building energy consumption, thermal environment and visual performance was proposed by introducing window orientation, window–wall ratio, window configuration, shading angle and length parameters. And it uses the non-dominated sequencing genetic algorithm NSGA-II and energy simulation software EnergyPlus. The corresponding Pareto solution set was obtained from the assumed room in a cold region, hot summer and cold winter region and hot summer and warm winter region, respectively. The optimal recommended values of window parameters in each direction were determined by analyzing the Pareto solution set. The effectiveness of the multi-objective optimization model is proved by using the linear weighted sum method, and the optimization method of sound insulation effect is discussed. The optimization model in this paper is helpful for designers to choose the optimal design scheme, so that it can comply with the design requirements in terms of energy consumption, thermal environment, visual performance and achieve the overall optimal performance.
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INDUCER OF CBF EXPRESSION 1 (ICE1) encodes a MYC-like basic helix-loop-helix (bHLH) transcription factor playing a critical role in plant responses to chilling and freezing stresses and leaf stomata development. However, no inform...
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INDUCER OF CBF EXPRESSION 1 (ICE1) encodes a MYC-like basic helix-loop-helix (bHLH) transcription factor playing a critical role in plant responses to chilling and freezing stresses and leaf stomata development. However, no information connecting ICE1 and reproductive development has been reported. In this study, we show that ICE1 controls plant male fertility via impacting anther dehydration. The loss-of-function mutation in ICE1 gene in Arabidopsis caused anther indehiscence and decreased pollen viability as well as germination rate. Further analysis revealed that the anthers in the mutant of ICE1 ( ice1-2 ) had the structure of stomium, though the epidermis did not shrink to dehisce. The anther indehiscence and influenced pollen viability as well as germination in ice1-2 were due to abnormal anther dehydration, for most of anthers dehisced with drought treatment and pollen grains from those dehydrated anthers had similar viability and germination rates compared with wild type. Accordingly, the sterility of ice1-2 could be rescued by ambient dehydration treatments. Likewise, the stomatal differentiation of ice1-2 anther epidermis was disrupted in a different manner compared with that in leaves. ICE1 specifically bound to MYC-recognition elements in the promoter of FAMA , a key regulator of guard cell differentiation, to activate FAMA expression. Transcriptome profiling in the anther tissues further exhibited ICE1-modulated genes associated with water transport and ion exchange in the anther. Together, this work reveals the key role of ICE1 in male fertility control and establishes a regulatory network mediated by ICE1 for stomata development and water movement in the anther. Author summary INDUCER OF CBF EXPRESSION 1 (ICE1) is a basic helix-loop-helix transcription factor playing multiple roles in Arabidopsis . It was initially identified as the activator of C-Repeat Binding Factor 3 (CBF3), a core modulator triggering cold acclimation. ICE1 also activates Flowering Locus C (FLC), a major repressor of floral transition, to delay flowering under fluctuating environmental stimuli. In normal conditions, ICE1 participates in control of stomatal development in leaves and endosperm breakdown in seeds. Here we describe a role of ICE1 in male fertility development of Arabidopsis . We provide evidence that ICE1 controls stomatal differentiation in the anther epidermis and thereby anther dehiscence and pollen viability as well as germination. Consequently, fertility of ice1 mutant can be rescued by ambient dehydration. ICE1 regulates FAMA , one key regulator of guard cell differentiation, through direct binding to MYC-recognition elements in FAMA promoter. Moreover, we perform transcriptomic analysis using anther tissues and identify ICE1-regulated genes involved in water transport. These findings reveal a novel role of ICE1 in male fertility regulation through affecting water movement in the anther, which deepens our understanding of coordination between plant development and stress response, and potentially contributes to the pollination controls in crop breeding.
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High-resolution soil moisture (SM) information is essential for regional to global hydrological and agricultural applications. The Soil Moisture Active Passive (SMAP) offers daily global composites of SM at coarse-resolution 9 and...
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High-resolution soil moisture (SM) information is essential for regional to global hydrological and agricultural applications. The Soil Moisture Active Passive (SMAP) offers daily global composites of SM at coarse-resolution 9 and 36 km, with data gaps limiting its local application to depict SM distribution in detail. To overcome the aforementioned problem, a downscaling and gap-filling novel approach was adopted, using random forest (RF) and artificial neural network (ANN) algorithms to downscale SMAP SM data, using land-surface variables from moderate-resolution imaging spectroradiometer (MODIS) onboard Aqua and Terra satellites from the years 2018 to 2019. Firstly, four combinations (RF+Aqua, RF+Terra, ANN+Aqua, and ANN+Terra) were developed. Each combination downscaled SMAP SM at a high resolution (1 km). These combinations were evaluated by using error matrices and in situ SM at different scales in the ShanDian River (SDR) Basin. The combination RF+Terra showed a better performance, with a low averaged unbiased root mean square error (ubRMSE) of 0.034 m3/m3 and high averaged correlation (R) of 0.54 against the small-, medium-, and large-scale in situ SM. Secondly, the impact of various land covers was examined by using downscaled SMAP and in situ SM. Vegetation attenuation makes woodland more error-prone and less correlated than grassland and farmland. Finally, the RF+Terra and ANN+Terra combinations were selected for their higher accuracy in gap filling of downscaled SMAP SM. The gap-filled downscaled SMAP SM results were compared spatially with China Land Data Assimilation System (CLDAS) SM and in situ SM. The RF+Terra combination outcomes were more humid than ANN+Terra combination results in the SDR basin. Overall, the RF+Terra combination gap-filled data showed high R (0.40) and less ubRMSE (0.064 m3/m3) against in situ SM, which was close to CLDAS SM. This study showed that the proposed RF- and ANN-based downscaling methods have a potential to improve the spatial resolution and gap-filling of SMAP SM at a high resolution (1 km).
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The existing literature on macroeconomic policy research is mainly concerned with the impact of a single monetary or fiscal policy on China's macroeconomic fiuctuations in a closed economy. However, the effect of a mix of monetary...
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The existing literature on macroeconomic policy research is mainly concerned with the impact of a single monetary or fiscal policy on China's macroeconomic fiuctuations in a closed economy. However, the effect of a mix of monetary and fiscal policies has been neglected. This paper addresses this issue with an open economy dynamic stochastic general equilibrium model. It applies impulse-response and welfare analyses to explore the stabilization effect of various mixes of monetary and fiscal policies. The results show that the optimal monetary policy and fiscal policy mix varies in different cases. When government spending shocks happen, the aggressive fiscal policy and passive monetary policy would be the best choice. In contrast, for domestic interest rate shocks, foreign interest rate shocks, and foreign consumption shocks, the passive fiscal policy and aggressive monetary policy are more applicable. This article explains China's economic fiuctuations and highlights the importance of mix of monetary and fiscal policies in the face of different shocks.
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Cell-based immunotherapy has become the new-generation cancer medicine, and ‘‘off-the-shelf’’ cell products that can be manufactured at large scale and distributed readily to treat patients are necessary. Invariant natural kil...
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Cell-based immunotherapy has become the new-generation cancer medicine, and ‘‘off-the-shelf’’ cell products that can be manufactured at large scale and distributed readily to treat patients are necessary. Invariant natural killer T (iNKT) cells are ideal cell carriers for developing allogeneic cell therapy because they are powerful immune cells targeting cancers without graft-versus-host disease (GvHD) risk. However, healthy donor blood contains extremely low numbers of endogenous iNKT cells. Here, by combining hematopoietic stem cell (HSC) gene engineering and in vitro differentiation, we generate human allogeneic HSC-engineered iNKT (AlloHSC-iNKT) cells at high yield and purity; these cells closely resemble endogenous iNKT cells, effectively target tumor cells using multiple mechanisms, and exhibit high safety and low immunogenicity. These cells can be further engineered with chimeric antigen receptor (CAR) to enhance tumor targeting or/and gene edited to ablate surface human leukocyte antigen (HLA) molecules and further reduce immunogenicity. Collectively, these preclinical studies demonstrate the feasibility and cancer therapy potential of AlloHSC-iNKT cell products and lay a foundation for their translational and clinical development.
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China has concluded a large number of international investment agreements (IIAs), many of which include investor-State arbitration (ISA) clauses. These clauses can be divided in three types: narrow, broad and special ISA sections,...
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China has concluded a large number of international investment agreements (IIAs), many of which include investor-State arbitration (ISA) clauses. These clauses can be divided in three types: narrow, broad and special ISA sections, each providing different admissibility requirements on disputes for ISA. While narrow ISA clauses allow disputes involving the amount of compensation for expropriation to be submitted to ISA, broad ISA clauses and special ISA sections generally allow a wider range of disputes for ISA The evolution of the ISA clauses shows China's shifting attitudes towards ISA from 'cautious' to 'proactive'. Such shift seems in favor of ISA and investors, but the impact of this shift remains to be seen.
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Container-based Hadoop distributed file system (HDFS) storage has been widely used in cloud data center networks, while traditional HDFS has single point problem resulting in overall unavailability. In this paper, we mainly study ...
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Container-based Hadoop distributed file system (HDFS) storage has been widely used in cloud data center networks, while traditional HDFS has single point problem resulting in overall unavailability. In this paper, we mainly study the storage reliability of the Docker container-based HDFS cluster with single point of failure. Firstly, we investigate a data volume-based persistence solution of Hadoop with the single point failure and single backup strategy of HDFS cluster. Secondly, we propose an HDFS-based replica placement algorithm for data storage with considering the performance of the host and container nodes. Thirdly, we design the KADC-KNN data segmentation algorithm to effectively store the persistent data of the Docker container. Extensive experimental results show that this method can effectively ensure the stable storage and fast migration of cluster data. Compared with the most advanced algorithm, the proposed data volume persistence algorithm DVPS can improve the data reliability by 19.8%. The data partitioning algorithm KADC-KNN improves the partitioning accuracy by 20.2% and has lower time overhead.
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Today's cloud services extensively rely on replication techniques to ensure availability and reliability. In complex datacenter network architectures, however, seemingly independent replica servers may inadvertently share deep dep...
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Today's cloud services extensively rely on replication techniques to ensure availability and reliability. In complex datacenter network architectures, however, seemingly independent replica servers may inadvertently share deep dependencies (e.g., aggregation switches). Such unexpected common dependencies may potentially result in correlated failures across the entire replication deployments, invalidating the efforts. Although existing cloud management and diagnosis tools have been able to offer post-failure forensics, they, nevertheless, typically lead to quite prolonged failure recovery time in the cloud-scale systems. In this paper, we propose a novel language framework, named RepAudit, that manages to prevent correlated failure risks before service outages occur, by allowing cloud administrators to proactively audit the replication deployments of interest. In particular, RepAudit consists of three new components: 1) a declarative domain-specific language, RAL, for cloud administrators to write auditing programs expressing diverse auditing tasks; 2) a high-performance RAL auditing engine that generates the auditing results by accurately and efficiently analyzing the underlying structures of the target replication deployments; and 3) an RAL-code generator that can automatically produce complex RAL programs based on easily written specifications. Our evaluation result shows that RepAudit uses 80x less lines of code than state-of-the-art efforts in expressing the auditing task of determining the top-20 critical correlated-failure root causes. To the best of our knowledge, RepAudit is the first effort capable of simultaneously offering expressive, accurate and efficient correlated failure auditing to the cloud-scale replication systems.
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The Tarim Craton, located in the center of Asia, was involved in the assembly and breakup of the Rodinia supercontinent during the Neoproterozoic and the subduction-accretion of the Central Asian Orogenic Belt (CAOB) during the Pa...
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The Tarim Craton, located in the center of Asia, was involved in the assembly and breakup of the Rodinia supercontinent during the Neoproterozoic and the subduction-accretion of the Central Asian Orogenic Belt (CAOB) during the Paleozoic. However, its tectonic evolution during these events is controversial, and a link between the Neoproterozoic and Paleozoic tectonic processes is missing. Here we present zircon U-Pb ages, Hf isotopes, and whole-rock geochemical data for the extensive granitoids in the western Kuruktag area, northeastern Tarim Craton. Three distinct periods of granitoid magmatism are evident: circa 830-820 Ma, 660-630 Ma, and 420-400 Ma. The magma sources, melting conditions (pressure, temperature, and water availability), and tectonic settings of various granitoids from each period are determined. Based on our results and the geological, geochronological, geochemical, and isotopic data from adjacent areas, a long-lived accretionary orogenic model is proposed. This model involves an early phase (circa 950-780 Ma) of southward advancing accretion from the Tianshan to northern Tarim and a late phase (circa 780-600 Ma) of northward retreating accretion, followed by back-arc opening and subsequent bidirectional subduction (circa 460-400 Ma) of a composite back-arc basin (i.e., the South Tianshan Ocean). Our model highlights a long-lived accretionary history of the southwestern CAOB, which may have initiated as part of the circum-Rodinia subduction zone and was comparable with events occurring at the southern margin of the Siberian Craton, thus challenging the traditional southward migrating accretionary models for the CAOB.
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