This paper examines the nutrition impacts of using non-solid cooking fuel on under-five children in developing countries.We draw on data from more than 1.12 million children in 62 developing countries from the Demogra...This paper examines the nutrition impacts of using non-solid cooking fuel on under-five children in developing countries.We draw on data from more than 1.12 million children in 62 developing countries from the Demographic and Health Surveys(DHS).Results from both fixed effects(FE)and instrumental variable(IV)estimates show that using non-solid cooking fuel significantly improves the nutrition outcomes of under-five children.Compared with their peers from households mainly using solid fuel,children from households mainly using non-solid fuel exhibit a lower probability of experiencing stunting(by 5.9 percentage points)and being underweight(by 1.2 percentage points).Our further investigation provides evidence for several underlying mechanisms,such as improved indoor air quality,induced reduction in children’s respiratory symptoms,benefits on maternal health,and reduction in maternal time spent on fuel collection or cooking.Heterogenous analyses suggest that the nutrition benefits of using non-solid cooking fuel are more prominent among boys,children above three years old,and those from households of lower socioeconomic status,rural areas,and Southeast Asia.展开更多
BACKGROUND Primary pancreatic paraganglioma is exceedingly rare.Most patients with pancreatic paraganglioma lack a typical clinical presentation,and the tumor is difficult to accurately differentiate from other pancre...BACKGROUND Primary pancreatic paraganglioma is exceedingly rare.Most patients with pancreatic paraganglioma lack a typical clinical presentation,and the tumor is difficult to accurately differentiate from other pancreatic neuroendocrine tumors,making the misdiagnosis rate extremely high.Surgical excision is the primary treatment modality but is considered high risk.Because of its rich vascularity,the tumor easily bleeds during surgery,especially malignant paragangliomas invading large blood vessels.Thus,a thorough preoperative evaluation of the tumor is necessary.Here,we report a primary malignant pancreatic paraganglioma,the second such case in a young patient that was successfully resected surgically.CASE SUMMARY A 26-year-old female patient was admitted to the hospital with unexplained abdominal pain.Dual-layer spectral-detector computed tomography(DLCT)revealed a mixed density mass in the pancreatic body and tail.The patient was transferred to our hospital after previous failed surgical resection at other hospitals.The patient and her family strongly desired surgery.After a thorough preoperative evaluation and adequate preparation,a large mass with the greatest dimension of 8.0 cm was successfully resected.The final pathological diagnosis was malignant paraganglioma.The patient was discharged in good condition 2 wk postoperatively.CONCLUSION The rare malignant pancreatic paraganglioma reported here was difficult to diagnose preoperatively.Early filling of the draining vein may be a crucial diagnostic imaging feature.DLCT can provide more precise information for surgical resection through dual-energy imaging.展开更多
Owing to extensive construction of dams, the impact of backwater on flow may lead to navigation or flood control issues in curved channels. To date, the impact of backwater on the water surface profile in curved chann...Owing to extensive construction of dams, the impact of backwater on flow may lead to navigation or flood control issues in curved channels. To date, the impact of backwater on the water surface profile in curved channels remains unknown and requires investigation. In this study, experiments were conducted in a glass-walled recirculating flume with a length of 19.4 m, a width of 0.6 m, and a depth of 0.8 m, and the impact of backwater on the water surface profile in a 90° channel bend was investigated. The experimental results showed that the backwater degree had a significant impact on the transverse and longitudinal flow depth distributions in the bend. The transverse slope of the flow (Jr) increased linearly with an increase in the Froude number of the approach flow upstream of the bend. Jr increased with the longitudinal location parameter ξ when −0.2 < ξ < 0.5, and decreased with ξ when 0.5 < ξ < 1.2. Furthermore, the results showed that Jr asymptotically decreased to zero with an increase in the degree of backwater. An equation was formulated to estimate the transverse slope of the flow in a 90° bend in backwater zones.展开更多
Nowadays,the advancement of nonintrusive load monitoring(NILM)has been hastened by the ever-increasing requirements for the reasonable use of electricity by users and demand side management.Although existing researche...Nowadays,the advancement of nonintrusive load monitoring(NILM)has been hastened by the ever-increasing requirements for the reasonable use of electricity by users and demand side management.Although existing researches have tried their best to extract a wide variety of load features based on transient or steady state of electrical appliances,it is still very difficult for their algorithm to model the load decomposition problem of different electrical appliance types in a targeted manner to jointly mine their proposed features.This paper presents a very effective event-driven NILM solution,which aims to separately model different appliance types to mine the unique characteristics of appliances from multi-dimensional features,so that all electrical appliances can achieve the best classification performance.First,we convert the multi-classification problem into a serial multiple binary classification problem through a pre-sort model to simplify the original problem.Then,ConTrastive Loss K-Nearest Neighbour(CTLKNN)model with trainable weights is proposed to targeted mine appliance load characteristics.The simulation results show the effectiveness and stability of the proposed algorithm.Compared with existing algorithms,the proposed algorithm has improved the identification performance of all electrical appliance types.展开更多
The breeding and large-scale application of hybrid rice contribute significantly to the food supply worldwide.Currently,hybrid seed production uses cytoplasmic male sterile(CMS)lines or photoperiod/thermo-sensitive ge...The breeding and large-scale application of hybrid rice contribute significantly to the food supply worldwide.Currently,hybrid seed production uses cytoplasmic male sterile(CMS)lines or photoperiod/thermo-sensitive genic male sterile(PTGMS)lines as female parent.Despite huge successes,both systems have intrinsic problems.CMS systems are mainly restricted by the narrow restorer resources that make it difficult to breed superior hybrids,while PTGMS systems are limited by conditional sterility of the male sterile lines that makes the propagation of both PTGMS seeds and hybrid seeds vulnerable to unpredictable climate changes.Recessive nuclear male sterile(NMS)lines insensitive to environmental conditions are widely distributed and are ideal for hybrid rice breeding and production,but the lack of effective ways to propagate the pure NMS lines in a large scale renders it impossible to use them for hybrid rice production.The development of"the third-generation hybrid rice technology"enables efficient propagation of the pure NMS lines in commercial scale.This paper discusses the establishment of"the thirdgeneration hybrid rice technology"and further innovations.This new technology breaks the limitations of CMS and PTGMS systems and will bring a big leap forward in hybrid rice production.展开更多
The fluid dynamic behavior of feeding gas(Ti Cl4) in an annular channel affects the combination of O2 and Ti Cl4 in an oxidation reactor, a key piece of equipment in titanium pigment production. The numerical procedur...The fluid dynamic behavior of feeding gas(Ti Cl4) in an annular channel affects the combination of O2 and Ti Cl4 in an oxidation reactor, a key piece of equipment in titanium pigment production. The numerical procedure was validated by a 3-dimensional gas flow in the annular channel. Applying the validated model, the flow characteristics of Ti Cl4 in the oxidation reactor with a tangential inlet were simulated and characterized. The flow distribution with five rectifying rings of different structure was simulated and analyzed. The results showed that the rectifying ring improved the distribution uniformity of the pressure and outlet velocity. Compared to the original case without a rectifying ring, the non-uniformity of the pressure and outlet velocity could be reduced by up to91% and 69% respectively. The rectifying ring #5, which can be installed and adjusted easily, is more effective in realizing even distribution. In addition, installation of the rectifying ring effectively reduced the circulating flow in an annular channel as well as the total energy loss.展开更多
Herbicide resistance in crop plants is valuable for integrated weed management in agriculture. Herbicide resistant rice, in particular, is important to management of weedy rice, a close relative of cultivated rice and...Herbicide resistance in crop plants is valuable for integrated weed management in agriculture. Herbicide resistant rice, in particular, is important to management of weedy rice, a close relative of cultivated rice and a noxious weed prevalent in rice fields that remains challenging to farmers worldwide. Herbicide resistant plants can be obtained through transgenic approach or by mutagenesis of regular plant and screening of mutants with elevated resistance to herbicide. In this study, we conducted ethyl methyl sulfonate mutagenesis(EMS) to elite indica cultivar Huanghuazhan(HHZ) and screened for mutants resistant to imazapic, a herbicide that can inhibit the acetolactate synthase(ALS) in plants. We obtained three mutants of Os ALS gene that have not been reported previously in rice. One of the mutants, with Trp_(548) changed to Met(W_(548)M), was analyzed in more details in this study. This mutation had no negative effect on the plant physiology and morphology as well as rice yield. Compared with the imidazolinone-resistant mutant S_(627)N(Ser_(627) changed to Asn) that has been deployed for Clearfield rice development, W_(548)M mutant showed high levels of resistance to a broad spectrum of five families of ALSinhibiting herbicides, in addition to a higher level of resistance to herbicides of the imidazolinone family.The herbicide-resistance was stably inherited by crossing into other rice lines. Thus, the W_(548)M mutation provides a valuable resource for breeding of herbicide resistant rice and weed management.展开更多
Mud shale hydration and swelling are major challenges in the development of water-based drilling fuids(WBDFs).In this work,the inhibition performance and inhibition mechanism of polyethylene glycol(PEG)and potassium c...Mud shale hydration and swelling are major challenges in the development of water-based drilling fuids(WBDFs).In this work,the inhibition performance and inhibition mechanism of polyethylene glycol(PEG)and potassium chloride(KCl)were investigated by hot rolling recovery tests,linear swell tests,Fourier transform infrared spectroscopy,X-ray difraction,atomic absorption spectrophotometry and X-ray photoelectron spectroscopy.The experimental results show that the combination of PEG and KCl achieved higher recovery and lower linear swelling rate than those obtained by individual PEG or KCl.Compared to the d-spacing of Na-montmorillonite(Na-Mt)with PEG or KCl,the d-spacing of Na-Mt with PEG+KCl was lower,which indicates that KCl and PEG have synergistic inhibition efect.This synergistic efect can replace sodium ions and water molecules from the interlayer space of Na-Mt and decrease the d-spacing of Na-Mt.Based on the above experimental results and analysis,a method for optimizing PEG and KCl concentrations was proposed and further verifed by rheological and hot rolling recovery tests of WBDFs.Hence,the results of this work can provide valuable theoretical guidance for developing other synergistic inhibitors.展开更多
The physical mechanisms of Ti/Al/Ni/Au ohmic contacts to AlGaN/GaN heterostructures by laser annealing and rapid thermal annealing are systematically investigated. The microstructures indicate that a better surface mo...The physical mechanisms of Ti/Al/Ni/Au ohmic contacts to AlGaN/GaN heterostructures by laser annealing and rapid thermal annealing are systematically investigated. The microstructures indicate that a better surface morphology and an intact contact interface are formed after laser annealing. None of the TiN alloy spikes are formed at the interface of the laser annealing sample. The experimental results show that the current transport mechanism through the ohmic contact after laser annealing is different from the conventional spike mechanism, and it is dominated by thermionic field emission.展开更多
The technology that silicic acid was pressurized under high temperature in order to dehydrate and transform was investigated in the paper.The effects,such as the ratio of liquid to solid,pressure,temperature,and react...The technology that silicic acid was pressurized under high temperature in order to dehydrate and transform was investigated in the paper.The effects,such as the ratio of liquid to solid,pressure,temperature,and reaction time on the dehydration rate and volume shrinkage rate,were researched.The experimental results show that the dehydration rate of silicic acid is up to 41.20%,accompanying with the volume shrinkage rate of 40.37%after silicic acid is pressurized under high temperature in the high-pressure kettle.The results of silicic acid tested by SEM indicate that the metasilicate acid molecules and water molecules are closely arranged,and there are almost no gaps before pressure reaction.There are many gaps accompanying with formatting lamellar structure after pressure reaction.The experimental results indicate the effect that silicic acid is dehydrated and transformation is obvious under high temperature and pressure.展开更多
Due to its difficulty in early diagnosis and lack of sensitivity to chemotherapy and radiotherapy,renal cell carcinoma(RCC)remains to be a frequent cause of cancer-related death.Here,we probed into new targets for its ...Due to its difficulty in early diagnosis and lack of sensitivity to chemotherapy and radiotherapy,renal cell carcinoma(RCC)remains to be a frequent cause of cancer-related death.Here,we probed into new targets for its early diagnosis and treatment for RCC.microRNA(miRNA)data of M2-EVs and RCC were searched on the Gene Expression Omnibus database,followed by the prediction of the potential downstream target.Expression of target genes was measured via RT-qPCR and Western blot,respectively.M2 macrophage was obtained viaflow cytometry with M2-EVs extracted.The binding ability of miR-342-3p to NEDD4L and to CEP55 ubiquitination was studied with their roles in the physical abilities of RCC cells assayed.Subcutaneous tumor-bearing mouse models and lung metastasis models were prepared to observe in vivo role of target genes.M2-EVs induced RCC growth and metastasis.miR-342-3p showed high expression in both M2-EVs and RCC cells.M2-EVs carrying miR-342-3p promoted RCC cell abilities to proliferate,invade and migrate.In RCC cells,M2-EV-derived miR-342-3p could specifically bind to NEDD4L and consequently elevate CEP55 protein expression via suppressing NEDD4L,thereby exerting tumor-promoting effects.CEP55 could be degraded by ubiquitination under the function of NEDD4L,and miR-342-3p delivered by M2-EVs facilitated the RCC occurrence and development by activating the PI3K/AKT/mTOR signaling pathway.In conclusion,M2-EVs promote RCC growth and metastasis by delivering miR-342-3p to suppress NEDD4L and subsequently inhibit CEP55 ubiquitination and degradation via activation of the PI3K/AKT/mTOR signaling pathway,strongly driving the proliferative,migratory and invasive of RCC cells.展开更多
AlGaN/GaN high-electron-mobility transistors with Au-free ohmic contacts are fabricated by selective laser annealing and conventional rapid thermal annealing.The current transport mechanism of ohmic contacts is invest...AlGaN/GaN high-electron-mobility transistors with Au-free ohmic contacts are fabricated by selective laser annealing and conventional rapid thermal annealing.The current transport mechanism of ohmic contacts is investigated.High-temperature annealing can be avoided in the isolated region and the active region by selective laser annealing.The implanted isolation leakage current is maintained 10^(-6) mA/mm even at 1000 V after selective laser annealing.On the contrary,high-temperature annealing will cause obvious degradation of the isolation.The morphology of AlGaN surface is measured by atomic force microscope.No noticeable change of the AlGaN surface morphology after selective laser annealing,while the root-mean-square roughness value markedly increases after rapid thermal annealing.The smaller frequency dispersion of capacitance-voltage characteristics confirms the lower density of surface states after selective laser annealing.Thus,dynamic on-resistance is effectively suppressed.展开更多
CeN_(3)O_(9)·6H_(2)O(0.5,1.0,1.5,and 2.0 g/L)was added into an 8.0%NaCl electrolyte solution to investigate this electrolyte for use in a Mg-air battery.The effects of the amount of CeN_(3)O_(9)-6H_(2)O on the co...CeN_(3)O_(9)·6H_(2)O(0.5,1.0,1.5,and 2.0 g/L)was added into an 8.0%NaCl electrolyte solution to investigate this electrolyte for use in a Mg-air battery.The effects of the amount of CeN_(3)O_(9)-6H_(2)O on the corrosion resistance of an AZ31 Mg alloy anode and battery performance were investigated using microstructure,electrochemical(dynamic potential polarization method and electrochemical impedance spectroscopy),and battery measurements.The re sults show that the addition of CeN_(3)O_(9)·6H_(2)O to the electrolyte leads to the formation of a Ce(OH)_(3)protective film on the surface of the AZ31 Mg alloy that improves the corrosion resistance of the Mg alloy.An increase in the concentration of CeN_(3)O_(9)·6H_(2)O results in a denser Ce(OH)_(3)protective film and decreases corrosion rate of the AZ31 Mg alloy.When the concentration of CeN_(3)O_(9)·6H_(2)O is 1.0 g/L,the corrosion rate of the Mg alloy is the lowest with a corrosion inhibition rate of70.4%.However,the corrosion rate increases due to the dissolution of the Ce(OH)_(3)protective film when the concentration of CeN_(3)O_(9)-6H_(2)O is greater than 1.0 g/L.Immersing the Mg alloy in the electrolyte solution containing CeN_(3)O_(9)-6H_(2)O for 50 h leads to the formation of the Ce(HO)_(3)protective film on its surface,which was confirmed by scanning electron microscopy of the AZ31 alloy.The Mg^(2+)charge transfer resistance increases by 69.5Ωfrom the equivalent circuit diagram,which improves the corrosion resistance of the Mg alloy.The discharge performance of CeN_(3)O_(9)·6H_(2)O improves according to a discharge test,and the discharge time increases by 40 min.展开更多
The self-assembly reactions between mixed-ligand and tetrahydrate dysprosium acetate in the presence of mixed organic solvents lead to two structural similar dinuclear dysprosium complexes with composition formulas of...The self-assembly reactions between mixed-ligand and tetrahydrate dysprosium acetate in the presence of mixed organic solvents lead to two structural similar dinuclear dysprosium complexes with composition formulas of Dy_(2)(L_1)_(2)(L_(2))_(2)(CH_(3)OH)_(2)·CH_(2)Cl_(2)·CH_(3)OH(1) and Dy_(2)(L_1)_(2)(L_(3))_(2)(CH_(3)OH)_(2)·CH_(3)CN(2),where L_1,L_(2) and L_(3) represent the deprotonated form of 4-tert-butyl-2-(7-methoxybenzo[d]oxazol-2-yl)phenol,(E)-1-(((3,5-di-tert-butyI-2-hydroxyphenyI)imino)methyl)naphthalen-2-ol and(E)-2,4-di-tertbutyl-6-((2-hydroxybenzylidene)amino)phenol.The tiny difference of the core structure of 1 and 2 is derived from the steric hindrance of Schiff base ligands L_(2) and L_(3).Dynamic magnetic measurements reveal that 1 and 2 show frequency-dependent out-of-phase alternating-current susceptibility signal peaks at different temperatures under zero dc field,diagnostic of single-molecule magnet behavior.The experimental derived energy barrier to magnetization reversal for 1 and 2 is 108(1),47(2) and 33(3) K.Ab initio CASSCF calculations performed on 1 and 2 suggest that the origin of the difference in magnetic properties originates from the variation in the single-ion anisotropy that arises due to minor structural variation.Further,the equation to calculate the effective energy barrier for Dy_(2) proposed earlier is found to yield an excellent agreement with the experimental results.Solid state fluorescence measurements performed on 1 and 2 demonstrate that both exhibit two ligands centered components of fluorescent emissive,in addition,with different emitting colors and chromaticity coordinates.The discrepancy of fluorescence and single molecule magnet behavior showed by 1 and 2 can be attributed to the steric hindrance effect of Schiff base ligands.展开更多
As the third generation new battery,the power conversion efficiency(PCE)of metal halide perovskite solar cells(PsCs)has increased from 3.8%in 2009 to 25.8%currently certified,which fully shows that they have great res...As the third generation new battery,the power conversion efficiency(PCE)of metal halide perovskite solar cells(PsCs)has increased from 3.8%in 2009 to 25.8%currently certified,which fully shows that they have great research value and development prospect.As one of the main components of high-efficiency PSCs,hole transport materials(HTMs)play an important role in extracting and transporting holes and inhibiting charge recombination.However,commonly used HTMs require doping,and the hygroscopicity and corrosiveness of the dopants will destroy the stability of PsCs and hinder their commercialization.Therefore,it is of great significance to develop dopant-free HTMs.展开更多
Passivating the interfacial defects and reducing the interfacial non-radiative recombination losses are the keys to improving the photovoltaic performance of three-dimensional(3D)perovskite solar cells(PVSCs).Stacking...Passivating the interfacial defects and reducing the interfacial non-radiative recombination losses are the keys to improving the photovoltaic performance of three-dimensional(3D)perovskite solar cells(PVSCs).Stacking two dimensional(2D)perovskites on 3D perovskite is a promising method for interfacial treatment that improves the stability and efficiency of PVSCs.Herein,we developed conjugated fluorinated benzimidazolium cation(FBIm+)which can be inserted between 3D perovskite and holetransporting layer(HTL)to form 2D perovskite in situ.The 2D single crystal structures of(FBIm)_(2)Pb I4and(FBIm)_(2)Pb Br_(4)were achieved and confirmed by single-crystal X-ray diffraction(XRD),while few single crystals of 2D perovskite based on imidazolium or benzimidazolium anchors have been reported.The 2D perovskite can passivate the interfacial defects,induce better crystallinity and orientation,conduct lower trap density and extend carrier lifetime.Furthermore,the energy level arrangement can be regulated by changing the counterion from iodide to bromide,which can efficiently improve the hole extraction and device performances.As a consequence,the best efficiency of 23.00%for FBIm Br-incorporated devices was achieved,while only 20.72%for the control device.Meanwhile,the PVSCs modified by FBIm Br displayed excellent environmental stability due to the constructed hydrophobic 2D perovskite layer which can effectively block moisture permeation.This work develops a new path to design novel conjugated organic passivants to form 2D/3D perovskite structures.展开更多
基金This work was supported by the National Natural Science Foundation of China(71861147003 and 71925009).
文摘This paper examines the nutrition impacts of using non-solid cooking fuel on under-five children in developing countries.We draw on data from more than 1.12 million children in 62 developing countries from the Demographic and Health Surveys(DHS).Results from both fixed effects(FE)and instrumental variable(IV)estimates show that using non-solid cooking fuel significantly improves the nutrition outcomes of under-five children.Compared with their peers from households mainly using solid fuel,children from households mainly using non-solid fuel exhibit a lower probability of experiencing stunting(by 5.9 percentage points)and being underweight(by 1.2 percentage points).Our further investigation provides evidence for several underlying mechanisms,such as improved indoor air quality,induced reduction in children’s respiratory symptoms,benefits on maternal health,and reduction in maternal time spent on fuel collection or cooking.Heterogenous analyses suggest that the nutrition benefits of using non-solid cooking fuel are more prominent among boys,children above three years old,and those from households of lower socioeconomic status,rural areas,and Southeast Asia.
文摘BACKGROUND Primary pancreatic paraganglioma is exceedingly rare.Most patients with pancreatic paraganglioma lack a typical clinical presentation,and the tumor is difficult to accurately differentiate from other pancreatic neuroendocrine tumors,making the misdiagnosis rate extremely high.Surgical excision is the primary treatment modality but is considered high risk.Because of its rich vascularity,the tumor easily bleeds during surgery,especially malignant paragangliomas invading large blood vessels.Thus,a thorough preoperative evaluation of the tumor is necessary.Here,we report a primary malignant pancreatic paraganglioma,the second such case in a young patient that was successfully resected surgically.CASE SUMMARY A 26-year-old female patient was admitted to the hospital with unexplained abdominal pain.Dual-layer spectral-detector computed tomography(DLCT)revealed a mixed density mass in the pancreatic body and tail.The patient was transferred to our hospital after previous failed surgical resection at other hospitals.The patient and her family strongly desired surgery.After a thorough preoperative evaluation and adequate preparation,a large mass with the greatest dimension of 8.0 cm was successfully resected.The final pathological diagnosis was malignant paraganglioma.The patient was discharged in good condition 2 wk postoperatively.CONCLUSION The rare malignant pancreatic paraganglioma reported here was difficult to diagnose preoperatively.Early filling of the draining vein may be a crucial diagnostic imaging feature.DLCT can provide more precise information for surgical resection through dual-energy imaging.
基金supported by the National Key Research and Development Program of China(Grant No.2019YFC1510701)the National Natural Science Foundation of China(Grant No.U20A20319).
文摘Owing to extensive construction of dams, the impact of backwater on flow may lead to navigation or flood control issues in curved channels. To date, the impact of backwater on the water surface profile in curved channels remains unknown and requires investigation. In this study, experiments were conducted in a glass-walled recirculating flume with a length of 19.4 m, a width of 0.6 m, and a depth of 0.8 m, and the impact of backwater on the water surface profile in a 90° channel bend was investigated. The experimental results showed that the backwater degree had a significant impact on the transverse and longitudinal flow depth distributions in the bend. The transverse slope of the flow (Jr) increased linearly with an increase in the Froude number of the approach flow upstream of the bend. Jr increased with the longitudinal location parameter ξ when −0.2 < ξ < 0.5, and decreased with ξ when 0.5 < ξ < 1.2. Furthermore, the results showed that Jr asymptotically decreased to zero with an increase in the degree of backwater. An equation was formulated to estimate the transverse slope of the flow in a 90° bend in backwater zones.
基金supported by National Natural Science Foundation of China(No.61531007).
文摘Nowadays,the advancement of nonintrusive load monitoring(NILM)has been hastened by the ever-increasing requirements for the reasonable use of electricity by users and demand side management.Although existing researches have tried their best to extract a wide variety of load features based on transient or steady state of electrical appliances,it is still very difficult for their algorithm to model the load decomposition problem of different electrical appliance types in a targeted manner to jointly mine their proposed features.This paper presents a very effective event-driven NILM solution,which aims to separately model different appliance types to mine the unique characteristics of appliances from multi-dimensional features,so that all electrical appliances can achieve the best classification performance.First,we convert the multi-classification problem into a serial multiple binary classification problem through a pre-sort model to simplify the original problem.Then,ConTrastive Loss K-Nearest Neighbour(CTLKNN)model with trainable weights is proposed to targeted mine appliance load characteristics.The simulation results show the effectiveness and stability of the proposed algorithm.Compared with existing algorithms,the proposed algorithm has improved the identification performance of all electrical appliance types.
基金supported by the National Natural Science Foundation of China(U1901203)Natural Science Foundation of Guangdong Province(2018B030308008 and 2019A1515110671)+2 种基金Major Program of Guangdong Basic and Applied Research(2019B030302006)Shenzhen Commission on Innovation and Technology Programs(JCYJ20180507181837997)China Postdoctoral Science Foundation(2019M662957)。
文摘The breeding and large-scale application of hybrid rice contribute significantly to the food supply worldwide.Currently,hybrid seed production uses cytoplasmic male sterile(CMS)lines or photoperiod/thermo-sensitive genic male sterile(PTGMS)lines as female parent.Despite huge successes,both systems have intrinsic problems.CMS systems are mainly restricted by the narrow restorer resources that make it difficult to breed superior hybrids,while PTGMS systems are limited by conditional sterility of the male sterile lines that makes the propagation of both PTGMS seeds and hybrid seeds vulnerable to unpredictable climate changes.Recessive nuclear male sterile(NMS)lines insensitive to environmental conditions are widely distributed and are ideal for hybrid rice breeding and production,but the lack of effective ways to propagate the pure NMS lines in a large scale renders it impossible to use them for hybrid rice production.The development of"the third-generation hybrid rice technology"enables efficient propagation of the pure NMS lines in commercial scale.This paper discusses the establishment of"the thirdgeneration hybrid rice technology"and further innovations.This new technology breaks the limitations of CMS and PTGMS systems and will bring a big leap forward in hybrid rice production.
基金Supported by the National Natural Science Foundation of China(21566015,51404123)the Applied Basic Research Projects of Yunnan(2013FC002,2013FC003,2015FB126)the Provincial Personnel Training Funds of Yunnan Province of China(KKSY201352109,KKPT201563013)
文摘The fluid dynamic behavior of feeding gas(Ti Cl4) in an annular channel affects the combination of O2 and Ti Cl4 in an oxidation reactor, a key piece of equipment in titanium pigment production. The numerical procedure was validated by a 3-dimensional gas flow in the annular channel. Applying the validated model, the flow characteristics of Ti Cl4 in the oxidation reactor with a tangential inlet were simulated and characterized. The flow distribution with five rectifying rings of different structure was simulated and analyzed. The results showed that the rectifying ring improved the distribution uniformity of the pressure and outlet velocity. Compared to the original case without a rectifying ring, the non-uniformity of the pressure and outlet velocity could be reduced by up to91% and 69% respectively. The rectifying ring #5, which can be installed and adjusted easily, is more effective in realizing even distribution. In addition, installation of the rectifying ring effectively reduced the circulating flow in an annular channel as well as the total energy loss.
基金supported by Major Program of Guangdong Basic and Applied Research(2019B030302006)National Natural Science Foundation of China(U1901203 and 31901532)+2 种基金Natural Science Foundation of Guangdong Province(2018B030308008 and 2018A0303130270)Shenzhen Commission on Innovation and Technology Programs(JCYJ20180507181837997)China Postdoctoral Science Foundation(2018M633069 and 2019M652920)。
文摘Herbicide resistance in crop plants is valuable for integrated weed management in agriculture. Herbicide resistant rice, in particular, is important to management of weedy rice, a close relative of cultivated rice and a noxious weed prevalent in rice fields that remains challenging to farmers worldwide. Herbicide resistant plants can be obtained through transgenic approach or by mutagenesis of regular plant and screening of mutants with elevated resistance to herbicide. In this study, we conducted ethyl methyl sulfonate mutagenesis(EMS) to elite indica cultivar Huanghuazhan(HHZ) and screened for mutants resistant to imazapic, a herbicide that can inhibit the acetolactate synthase(ALS) in plants. We obtained three mutants of Os ALS gene that have not been reported previously in rice. One of the mutants, with Trp_(548) changed to Met(W_(548)M), was analyzed in more details in this study. This mutation had no negative effect on the plant physiology and morphology as well as rice yield. Compared with the imidazolinone-resistant mutant S_(627)N(Ser_(627) changed to Asn) that has been deployed for Clearfield rice development, W_(548)M mutant showed high levels of resistance to a broad spectrum of five families of ALSinhibiting herbicides, in addition to a higher level of resistance to herbicides of the imidazolinone family.The herbicide-resistance was stably inherited by crossing into other rice lines. Thus, the W_(548)M mutation provides a valuable resource for breeding of herbicide resistant rice and weed management.
基金This work was financially supported by the Natural Science Foundation of China(51974270)Innovation Union of China National Petroleum Corporation and Southwest Petroleum University(2020CX040102,2020CX040201)Open Fund(PLN201814)of the State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation(Southwest Petroleum University).
文摘Mud shale hydration and swelling are major challenges in the development of water-based drilling fuids(WBDFs).In this work,the inhibition performance and inhibition mechanism of polyethylene glycol(PEG)and potassium chloride(KCl)were investigated by hot rolling recovery tests,linear swell tests,Fourier transform infrared spectroscopy,X-ray difraction,atomic absorption spectrophotometry and X-ray photoelectron spectroscopy.The experimental results show that the combination of PEG and KCl achieved higher recovery and lower linear swelling rate than those obtained by individual PEG or KCl.Compared to the d-spacing of Na-montmorillonite(Na-Mt)with PEG or KCl,the d-spacing of Na-Mt with PEG+KCl was lower,which indicates that KCl and PEG have synergistic inhibition efect.This synergistic efect can replace sodium ions and water molecules from the interlayer space of Na-Mt and decrease the d-spacing of Na-Mt.Based on the above experimental results and analysis,a method for optimizing PEG and KCl concentrations was proposed and further verifed by rheological and hot rolling recovery tests of WBDFs.Hence,the results of this work can provide valuable theoretical guidance for developing other synergistic inhibitors.
基金supported by the National Natural Science Foundation of China(Grant Nos.51577169 and 51777187)the National Key Research and Development Program of China(Grant No.2017YFB0402804)
文摘The physical mechanisms of Ti/Al/Ni/Au ohmic contacts to AlGaN/GaN heterostructures by laser annealing and rapid thermal annealing are systematically investigated. The microstructures indicate that a better surface morphology and an intact contact interface are formed after laser annealing. None of the TiN alloy spikes are formed at the interface of the laser annealing sample. The experimental results show that the current transport mechanism through the ohmic contact after laser annealing is different from the conventional spike mechanism, and it is dominated by thermionic field emission.
基金supported by the Social Development Plan of Science and Technology-Scientific Research Institute Technology and Development Research Project in Yunnan Province (No. 2009CF011)
文摘The technology that silicic acid was pressurized under high temperature in order to dehydrate and transform was investigated in the paper.The effects,such as the ratio of liquid to solid,pressure,temperature,and reaction time on the dehydration rate and volume shrinkage rate,were researched.The experimental results show that the dehydration rate of silicic acid is up to 41.20%,accompanying with the volume shrinkage rate of 40.37%after silicic acid is pressurized under high temperature in the high-pressure kettle.The results of silicic acid tested by SEM indicate that the metasilicate acid molecules and water molecules are closely arranged,and there are almost no gaps before pressure reaction.There are many gaps accompanying with formatting lamellar structure after pressure reaction.The experimental results indicate the effect that silicic acid is dehydrated and transformation is obvious under high temperature and pressure.
基金supported by the Science and Technology Department of Sichuan Province(2015SZ0117,2019YJ0701,and 2021YJ0239).
文摘Due to its difficulty in early diagnosis and lack of sensitivity to chemotherapy and radiotherapy,renal cell carcinoma(RCC)remains to be a frequent cause of cancer-related death.Here,we probed into new targets for its early diagnosis and treatment for RCC.microRNA(miRNA)data of M2-EVs and RCC were searched on the Gene Expression Omnibus database,followed by the prediction of the potential downstream target.Expression of target genes was measured via RT-qPCR and Western blot,respectively.M2 macrophage was obtained viaflow cytometry with M2-EVs extracted.The binding ability of miR-342-3p to NEDD4L and to CEP55 ubiquitination was studied with their roles in the physical abilities of RCC cells assayed.Subcutaneous tumor-bearing mouse models and lung metastasis models were prepared to observe in vivo role of target genes.M2-EVs induced RCC growth and metastasis.miR-342-3p showed high expression in both M2-EVs and RCC cells.M2-EVs carrying miR-342-3p promoted RCC cell abilities to proliferate,invade and migrate.In RCC cells,M2-EV-derived miR-342-3p could specifically bind to NEDD4L and consequently elevate CEP55 protein expression via suppressing NEDD4L,thereby exerting tumor-promoting effects.CEP55 could be degraded by ubiquitination under the function of NEDD4L,and miR-342-3p delivered by M2-EVs facilitated the RCC occurrence and development by activating the PI3K/AKT/mTOR signaling pathway.In conclusion,M2-EVs promote RCC growth and metastasis by delivering miR-342-3p to suppress NEDD4L and subsequently inhibit CEP55 ubiquitination and degradation via activation of the PI3K/AKT/mTOR signaling pathway,strongly driving the proliferative,migratory and invasive of RCC cells.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.51577169 and 51777187)the National Key Research and Development Program of China(Grant No.2017YFB0402804)the“Science and Technology Innovation 2025”Major Program of Ningbo(Grant No.2018B10098).
文摘AlGaN/GaN high-electron-mobility transistors with Au-free ohmic contacts are fabricated by selective laser annealing and conventional rapid thermal annealing.The current transport mechanism of ohmic contacts is investigated.High-temperature annealing can be avoided in the isolated region and the active region by selective laser annealing.The implanted isolation leakage current is maintained 10^(-6) mA/mm even at 1000 V after selective laser annealing.On the contrary,high-temperature annealing will cause obvious degradation of the isolation.The morphology of AlGaN surface is measured by atomic force microscope.No noticeable change of the AlGaN surface morphology after selective laser annealing,while the root-mean-square roughness value markedly increases after rapid thermal annealing.The smaller frequency dispersion of capacitance-voltage characteristics confirms the lower density of surface states after selective laser annealing.Thus,dynamic on-resistance is effectively suppressed.
基金Project supported by the National Natural Science Foundation of China(22168019,52074141)。
文摘CeN_(3)O_(9)·6H_(2)O(0.5,1.0,1.5,and 2.0 g/L)was added into an 8.0%NaCl electrolyte solution to investigate this electrolyte for use in a Mg-air battery.The effects of the amount of CeN_(3)O_(9)-6H_(2)O on the corrosion resistance of an AZ31 Mg alloy anode and battery performance were investigated using microstructure,electrochemical(dynamic potential polarization method and electrochemical impedance spectroscopy),and battery measurements.The re sults show that the addition of CeN_(3)O_(9)·6H_(2)O to the electrolyte leads to the formation of a Ce(OH)_(3)protective film on the surface of the AZ31 Mg alloy that improves the corrosion resistance of the Mg alloy.An increase in the concentration of CeN_(3)O_(9)·6H_(2)O results in a denser Ce(OH)_(3)protective film and decreases corrosion rate of the AZ31 Mg alloy.When the concentration of CeN_(3)O_(9)·6H_(2)O is 1.0 g/L,the corrosion rate of the Mg alloy is the lowest with a corrosion inhibition rate of70.4%.However,the corrosion rate increases due to the dissolution of the Ce(OH)_(3)protective film when the concentration of CeN_(3)O_(9)-6H_(2)O is greater than 1.0 g/L.Immersing the Mg alloy in the electrolyte solution containing CeN_(3)O_(9)-6H_(2)O for 50 h leads to the formation of the Ce(HO)_(3)protective film on its surface,which was confirmed by scanning electron microscopy of the AZ31 alloy.The Mg^(2+)charge transfer resistance increases by 69.5Ωfrom the equivalent circuit diagram,which improves the corrosion resistance of the Mg alloy.The discharge performance of CeN_(3)O_(9)·6H_(2)O improves according to a discharge test,and the discharge time increases by 40 min.
基金Project supported by National Natural Science Foundation of China (21601143)Natural Science Foundation of Shaanxi Province (2021JM309)+2 种基金Open Funds of the State Key Laboratory of Rare Earth Resource of Changchun Institute of Applied Chemistry (RERU2021012)Science and Technology Innovation Team Program of Shaanxi Province (2022TD-32) and DST/SERB (CRG/2018/000430,DST/SJF/CSA03/2018-10SB/SJF/2019-20/12)。
文摘The self-assembly reactions between mixed-ligand and tetrahydrate dysprosium acetate in the presence of mixed organic solvents lead to two structural similar dinuclear dysprosium complexes with composition formulas of Dy_(2)(L_1)_(2)(L_(2))_(2)(CH_(3)OH)_(2)·CH_(2)Cl_(2)·CH_(3)OH(1) and Dy_(2)(L_1)_(2)(L_(3))_(2)(CH_(3)OH)_(2)·CH_(3)CN(2),where L_1,L_(2) and L_(3) represent the deprotonated form of 4-tert-butyl-2-(7-methoxybenzo[d]oxazol-2-yl)phenol,(E)-1-(((3,5-di-tert-butyI-2-hydroxyphenyI)imino)methyl)naphthalen-2-ol and(E)-2,4-di-tertbutyl-6-((2-hydroxybenzylidene)amino)phenol.The tiny difference of the core structure of 1 and 2 is derived from the steric hindrance of Schiff base ligands L_(2) and L_(3).Dynamic magnetic measurements reveal that 1 and 2 show frequency-dependent out-of-phase alternating-current susceptibility signal peaks at different temperatures under zero dc field,diagnostic of single-molecule magnet behavior.The experimental derived energy barrier to magnetization reversal for 1 and 2 is 108(1),47(2) and 33(3) K.Ab initio CASSCF calculations performed on 1 and 2 suggest that the origin of the difference in magnetic properties originates from the variation in the single-ion anisotropy that arises due to minor structural variation.Further,the equation to calculate the effective energy barrier for Dy_(2) proposed earlier is found to yield an excellent agreement with the experimental results.Solid state fluorescence measurements performed on 1 and 2 demonstrate that both exhibit two ligands centered components of fluorescent emissive,in addition,with different emitting colors and chromaticity coordinates.The discrepancy of fluorescence and single molecule magnet behavior showed by 1 and 2 can be attributed to the steric hindrance effect of Schiff base ligands.
基金supported by the National Natural Science Foundation of China(Nos.51763013 and U20A20128)Jiangxi Provincial Natural Science Foundation(No.20224ACB213002)+1 种基金the Foundation of Jiangxi Educational Committee(No.GJJ200301)Jiangxi Provincial High-level and High-skilled Leading Talents Project.
文摘As the third generation new battery,the power conversion efficiency(PCE)of metal halide perovskite solar cells(PsCs)has increased from 3.8%in 2009 to 25.8%currently certified,which fully shows that they have great research value and development prospect.As one of the main components of high-efficiency PSCs,hole transport materials(HTMs)play an important role in extracting and transporting holes and inhibiting charge recombination.However,commonly used HTMs require doping,and the hygroscopicity and corrosiveness of the dopants will destroy the stability of PsCs and hinder their commercialization.Therefore,it is of great significance to develop dopant-free HTMs.
基金supported by the National Natural Science Foundation of China(51763013)the Natural Science Foundation of Jiangxi Province(20224ACB213002)the Foundation of Jiangxi Educational Committee(GJJ200301)。
文摘Passivating the interfacial defects and reducing the interfacial non-radiative recombination losses are the keys to improving the photovoltaic performance of three-dimensional(3D)perovskite solar cells(PVSCs).Stacking two dimensional(2D)perovskites on 3D perovskite is a promising method for interfacial treatment that improves the stability and efficiency of PVSCs.Herein,we developed conjugated fluorinated benzimidazolium cation(FBIm+)which can be inserted between 3D perovskite and holetransporting layer(HTL)to form 2D perovskite in situ.The 2D single crystal structures of(FBIm)_(2)Pb I4and(FBIm)_(2)Pb Br_(4)were achieved and confirmed by single-crystal X-ray diffraction(XRD),while few single crystals of 2D perovskite based on imidazolium or benzimidazolium anchors have been reported.The 2D perovskite can passivate the interfacial defects,induce better crystallinity and orientation,conduct lower trap density and extend carrier lifetime.Furthermore,the energy level arrangement can be regulated by changing the counterion from iodide to bromide,which can efficiently improve the hole extraction and device performances.As a consequence,the best efficiency of 23.00%for FBIm Br-incorporated devices was achieved,while only 20.72%for the control device.Meanwhile,the PVSCs modified by FBIm Br displayed excellent environmental stability due to the constructed hydrophobic 2D perovskite layer which can effectively block moisture permeation.This work develops a new path to design novel conjugated organic passivants to form 2D/3D perovskite structures.
