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双赢的新“公私合营”——介绍东方高圣著的《路线》一书
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作者 茅于轼 《竞争力》 2005年第2期61-61,共1页
东方高圣从事企业并购的业务,对这方面的知识我懂得很少,只能从经济学的角度,特别是制度经济学的角度谈一点看法。
关键词 《路线》 东方高圣 企业并购 国有企业 民有企业 书评
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Preoperative CT radiomics models for predicting composition of in vivo urinary calculi
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作者 TANG Lei WANG Shixia +3 位作者 LI Wuchao ZENG Xianchun AN Yunzhao SONG Bin 《中国医学影像技术》 CSCD 北大核心 2024年第8期1216-1220,共5页
Objective To observe the value of preoperative CT radiomics models for predicting composition of in vivo urinary calculi.Methods Totally 543 urolithiasis patients were retrospectively enrolled and divided into calcium... Objective To observe the value of preoperative CT radiomics models for predicting composition of in vivo urinary calculi.Methods Totally 543 urolithiasis patients were retrospectively enrolled and divided into calcium oxalate monohydrate stone group(group A,n=373),anhydrous uric acid stone group(group B,n=86),carbonate apatite group(group C,n=30),ammonium urate stone group(group D,n=28)and ammonium magnesium phosphate hexahydrate stone group(group E,n=26)according to the composition of calculi,also divided into training set and test set at the ratio of 7∶3.Radiomics features were extracted and screened based on plain CT images of urinary system.Five binary task models(model A—E corresponding to group A—E)and a quinary task model were constructed using least absolute shrinkage and selection operator algorithm for predicting the composition of calculi in vivo.Then receiver operating characteristic curves were drawn,and the area under the curves(AUC)were calculated to evaluate the predictive efficacy of binary task models,while the accuracy,precision,recall and F1 score were used to evaluate the predictive efficacy of the quinary task model.Results All binary task models had good efficacy for predicting the composition of urinary calculi in vivo,with AUC of 0.860—0.948 in training set and of 0.856—0.933 in test set.The accuracy,precision,recall and F1 score of the quinary task model for predicting the composition of in vivo urinary calculi was 82.25%,83.79%,46.23%and 0.596 in training set,respectively,while was 80.63%,75.26%,43.48%and 0.551 in test set,respectively.Conclusion Binary task radiomics models based on preoperative plain CT had good efficacy for predicting the composition of in vivo urinary calculi,while the quinary task radiomics model had high accuracy but relatively poor stability. 展开更多
关键词 UROLITHIASIS tomography X-ray computed radiomics
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Self-supervised learning artificial intelligence noise reduction technology based on the nearest adjacent layer in ultra-low dose CT of urinary calculi
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作者 ZHOU Cheng LIU Yang +4 位作者 QIU Yingwei HE Daijun YAN Yu LUO Min LEI Youyuan 《中国医学影像技术》 CSCD 北大核心 2024年第8期1249-1253,共5页
Objective To observe the value of self-supervised deep learning artificial intelligence(AI)noise reduction technology based on the nearest adjacent layer applicated in ultra-low dose CT(ULDCT)for urinary calculi.Metho... Objective To observe the value of self-supervised deep learning artificial intelligence(AI)noise reduction technology based on the nearest adjacent layer applicated in ultra-low dose CT(ULDCT)for urinary calculi.Methods Eighty-eight urinary calculi patients were prospectively enrolled.Low dose CT(LDCT)and ULDCT scanning were performed,and the effective dose(ED)of each scanning protocol were calculated.The patients were then randomly divided into training set(n=75)and test set(n=13),and a self-supervised deep learning AI noise reduction system based on the nearest adjacent layer constructed with ULDCT images in training set was used for reducing noise of ULDCT images in test set.In test set,the quality of ULDCT images before and after AI noise reduction were compared with LDCT images,i.e.Blind/Referenceless Image Spatial Quality Evaluator(BRISQUE)scores,image noise(SD ROI)and signal-to-noise ratio(SNR).Results The tube current,the volume CT dose index and the dose length product of abdominal ULDCT scanning protocol were all lower compared with those of LDCT scanning protocol(all P<0.05),with a decrease of ED for approximately 82.66%.For 13 patients with urinary calculi in test set,BRISQUE score showed that the quality level of ULDCT images before AI noise reduction reached 54.42%level but raised to 95.76%level of LDCT images after AI noise reduction.Both ULDCT images after AI noise reduction and LDCT images had lower SD ROI and higher SNR than ULDCT images before AI noise reduction(all adjusted P<0.05),whereas no significant difference was found between the former two(both adjusted P>0.05).Conclusion Self-supervised learning AI noise reduction technology based on the nearest adjacent layer could effectively reduce noise and improve image quality of urinary calculi ULDCT images,being conducive for clinical application of ULDCT. 展开更多
关键词 urinary calculi tomography X-ray computed artificial intelligence prospective studies
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Synthesis and photoluminescence properties of single-crystal ZnO hexagonal pyramids by PEG400-assisted thermal decomposition route 被引量:1
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作者 刘劲松 张朔 +6 位作者 李子全 朱孔军 陈建康 裘进浩 王春花 高雪琴 王莉萍 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第10期2459-2464,共6页
Large-scale synthesis of ZnO hexagonal pyramids was achieved by a simple thermal decomposition route of precursor at 240 oC in the presence of PEG400. The precursor was obtained by room-temperature solid-state grindin... Large-scale synthesis of ZnO hexagonal pyramids was achieved by a simple thermal decomposition route of precursor at 240 oC in the presence of PEG400. The precursor was obtained by room-temperature solid-state grinding reaction between Zn(CH3COO)2-2H2O and Na2CO3. Crystal structure and morphology of the products were analyzed and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The results of further experiments show that PEG400 has an important role in the formation of ZnO hexagonal pyramids. Difference between the single and double hexagonal pyramid structure may come from the special thermal decomposition reaction. The photoluminescence (PL) spectra of ZnO hexagonal pyramids exhibit strong near-band-edge emission at about 386 nm and weak green emission at about 550 nm. The Raman-active vibration at about 435 cm-1 suggests that the ZnO hexagonal pyramids have high crystallinity. 展开更多
关键词 ZnO hexagonal pyramids thermal decomposition route formation mechanism photoluminescence property
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The influence of sea water velocity variation on seismic traveltimes,ray paths,and amplitude 被引量:9
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作者 韩复兴 孙建国 王坤 《Applied Geophysics》 SCIE CSCD 2012年第3期319-325,361,362,共9页
The main factors affecting seismic exploration is the propagation velocity of seismic waves in the medium. In the past, during marine seismic data processing, the propagation velocity of sea water was generally taken ... The main factors affecting seismic exploration is the propagation velocity of seismic waves in the medium. In the past, during marine seismic data processing, the propagation velocity of sea water was generally taken as a constant 1500 m/s. However, for deep water exploration, the sound velocity varies with the season, time, location, water depth, ocean currents, and etc.. It also results in a layered velocity distribution, so there is a difference of seismic traveltime, ray paths, and amplitude, which affect the migration imaging results if sea water propagation velocity is still taken as constant for the propagation wavefield. In this paper, we will start from an empirical equation of seismic wave velocity in seawater with changes of temperature, salinity, and depth, consider the variation of their values, build a seawater velocity model, and quantitatively analyze the impact of seawater velocity variation on seismic traveltime, ray paths, and amplitude in the seawater velocity model. 展开更多
关键词 Sea water velocity TRAVELTIMES ray paths AMPLITUDE
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Design and Implementation of VPDN-based 3G Wireless Meteorological Information Transmission System 被引量:8
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作者 刘树峰 苏轶 +1 位作者 孟令旺 马骏 《Agricultural Science & Technology》 CAS 2012年第2期445-448,共4页
[Objective] This study was to construct VPDN-based 3G wireless meteorological information transmission system, in order to achieve the backup transmission of real-time meteorological services in all levels of meteorol... [Objective] This study was to construct VPDN-based 3G wireless meteorological information transmission system, in order to achieve the backup transmission of real-time meteorological services in all levels of meteorological stations. [Method] The current situations and business requirements of municipal meteorological networks are analyzed, putting forward the idea of backup routes that using VPDN-based 3G wireless meteorological information transmission system as the ground transmission line. And the network structure, operation mode and the system implementation are described in detail. [Result] VPDN-based 3G wireless meteorological information transmission system realizes the backup of ground line. Compared with the Modem dial-up, it is more stable and with faster transferring speed. With the rapid development of communication technology and computer technology, the information transmission system will be more efficient and stable, and will play a greater role in meteorological information transmission. [Conclusion] With the continuous development of modern meteorology, various types of meteorological data increase, presenting higher demand for the meteorological information transmission system. The established VPND-based 3G wireless meteorological information transmission system of this study provides a solution for backup transmission of real-time meteorological services. 展开更多
关键词 VPDN 3G Meteorological information Transmission system Backup line
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A Monolithic InGaP/GaAs HBT VCO for 5GHz Wireless Applications 被引量:1
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作者 陈立强 张健 +2 位作者 李志强 陈普锋 张海英 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第6期823-828,共6页
A monolithic voltage controlled oscillator (VCO) based on negative resistance principle is presented uti-lizing commercially available InGaP/GaAs hetero-junction bipolar transistor (HBT) technology. This VCO is de... A monolithic voltage controlled oscillator (VCO) based on negative resistance principle is presented uti-lizing commercially available InGaP/GaAs hetero-junction bipolar transistor (HBT) technology. This VCO is de-signed for 5GHz-band wireless applications. Except for bypass and decoupled capacitors,no external component is needed for real application. Its measured output frequency range is from 4.17 to 4.56GHz,which is very close to the simulation one. And the phase noise at an offset frequency of 1MHz is -112dBc/Hz. The VCO core dissipates 15.5mW from a 3.3V supply,and the output power ranges from 0 to 2dBm. To compare with other oscillators,the figure of merit is calculated,which is about -173.2dBc/Hz. Meanwhile, the principle and design method of nega-tive resistance oscillator are also discussed. 展开更多
关键词 VCO MMIC wireless communication InGaP/GaAs HBT
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Nonlinear dynamical response of high-voltage transmission lines based on cable dropping 被引量:1
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作者 夏开全 刘云 钱振东 《Journal of Southeast University(English Edition)》 EI CAS 2009年第1期52-56,共5页
In order to study the dynamic response of high-voltage transmission lines under mechanical failure, a finite element model of a domestic 500-kV high-voltage transmission line system is established. The initial equilib... In order to study the dynamic response of high-voltage transmission lines under mechanical failure, a finite element model of a domestic 500-kV high-voltage transmission line system is established. The initial equilibrium condition of the coupling system model is verified by nonlinear static analysis. The transient dynamic analysis method is proposed to analyze the variation law of dynamic response under cable or insulator rupture, and the dynamic response of structural elements next to the broken span is calculated. The results show that upper crossarm cable rupture has no effect on cable tension at adjacent suspension points, but it has a significant influence on tension in the insulator and the tower component of the upper crossarm next to the broken span. The peak tension in the conductor of the upper crossarm at the suspension point exceeds the design value under insulator rupture. Insulator rupture has no effect on the tower component of the upper crossarm, but it has a significant influence on insulator tension of the upper crossarm. Insulator rupture should be taken into account in the design of overhead transmission lines. The research results can provide a theoretical basis for the design of transmission lines. 展开更多
关键词 high-voltage transmission line transient response cable dropping numerical simulation finite element method
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NEW PRINCIPLE FOR DIRECTIONAL COMPARISON CARRIER PROTECTION OF EHV TRANSMISSION LINES 被引量:1
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作者 王钢 李遥 +2 位作者 余晓丹 刘众仆 贺家李 《Transactions of Tianjin University》 EI CAS 1998年第2期6-10,共5页
The increasing scale and complexity of power systems require high performance and high reliability of power system protection.Protective relaying based on directional comparison with power line carrier or microwave ch... The increasing scale and complexity of power systems require high performance and high reliability of power system protection.Protective relaying based on directional comparison with power line carrier or microwave channels is the most suitable protection scheme for long distance EHV transmission lines and is widely used in power systems.The key element of such protection is a directional relay used to discriminate the fault direction.In order to overcome the disadvantages of conventional directional relays,the authors of this paper put forward the directional comparison carrier protection based on the artificial neural network(ANN).The protection is extensively tested using electromagnetic transient program (EMTP) under various electric power system operating and fault conditions.It is proved that the directional comparison carrier protection based on ANN,which can recognize various fault patterns of the protected transmission line(such as fault direction,fault phases etc.)correctly in any kind of operating and fault conditions and the whole process,is satisfactory for EHV transmission line protection. 展开更多
关键词 artificial neural network EHV transmission line directional comparison carrier protection
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Ray path of head waves with irregular interfaces 被引量:1
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作者 周红 陈晓非 《Applied Geophysics》 SCIE CSCD 2010年第1期66-73,100,共9页
Head waves are usually considered to be the refracted waves propagating along flat interfaces with an underlying higher velocity.However,the path that the rays travel along in media with irregular interfaces is not cl... Head waves are usually considered to be the refracted waves propagating along flat interfaces with an underlying higher velocity.However,the path that the rays travel along in media with irregular interfaces is not clear.Here we study the problem by simulation using a new approach of the spectral-element method with some overlapped elements(SEMO) that can accurately evaluate waves traveling along an irregular interface.Consequently,the head waves are separated from interface waves by a time window.Thus,their energy and arrival time changes can be analyzed independently.These analyses demonstrate that,contrary to the case for head waves propagating along a flat interface,there are two mechanisms for head waves traveling along an irregular interface:a refraction mechanism and transmission mechanism.That is,the head waves may be refracted waves propagating along the interface or transmitted waves induced by the waves propagating in the higher-velocity media.Such knowledge will be helpful in constructing a more accurate inversion method,such as head wave travel-time tomography,and in obtaining a more accurate model of subsurface structure which is very important for understanding the formation mechanism of some special areas,such as the Tibetan Plateau. 展开更多
关键词 head waves irregular interface refracted waves transmitted waves ray path
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Research on large-scale cascading failure of power systems using synergistic effect 被引量:1
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作者 李扬 苏慧玲 +1 位作者 孙宇军 窦迅 《Journal of Southeast University(English Edition)》 EI CAS 2014年第1期32-38,共7页
This paper discusses the primary causes from the point of synergistic effects to improve power system vulnerability in the power system planning and safety operation. Based on the vulnerability conception in the compl... This paper discusses the primary causes from the point of synergistic effects to improve power system vulnerability in the power system planning and safety operation. Based on the vulnerability conception in the complex network theory the vulnerability of the power system can be evaluated by the minimum load loss rate when considering power supply ability.Consequently according to the synergistic effect theory the critical line of the power system is defined by its influence on failure set vulnerability in N-k contingencies.The cascading failure modes are proposed based on the criterion whether the acceptable load curtailment level is below a preset value.Significant conclusions are revealed by results of IEEE 39 case analysis weak points of power networks and heavy load condition are the main causes of large-scale cascading failures damaging synergistic effects can result in partial failure developed into large-scale cascading failures vulnerable lines of power systems can directly lead the partial failure to deteriorate into a large blackout while less vulnerable lines can cause a large-scale cascading failure. 展开更多
关键词 synergistic effect cascading failure power system vulnerability critical line load loss rate
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Recursive bisection placement algorithm with the predicted wirelength
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作者 蒿杰 马鸿 彭思龙 《Journal of Southeast University(English Edition)》 EI CAS 2008年第4期462-467,共6页
To obtain a better placement result, a partitioning-based placement algorithm with wirelength prediction called HJ-Pl is presented. A new method is proposed to estimate proximity of interconnects in a netlist, which i... To obtain a better placement result, a partitioning-based placement algorithm with wirelength prediction called HJ-Pl is presented. A new method is proposed to estimate proximity of interconnects in a netlist, which is capable of predicting not only short interconnects but long interconnects accurately. The predicted wirelength is embedded into the partitioning tool of bisection-based global placement, which can guide our placement towards a solution with shorter interconnects. In addition, the timing objective can be handled within the algorithm by minimizing the critical path delay. Experimental results show that, compared to Capol0. 5, mPL6, and NTUplace, HJ-P1 outperforms these placers in terms of wirelength and run time. The improvements in terms of average wirelength over Capo10. 5, mPL6 and NPUplace are 13%, 3%, and 9% with only 19%, 91%, and 99% of their runtime, respectively. By integrating the predicted wirelength-driven clustering into Capo10. 5, the placer is able to reduce average wirelength by 3%. The timing-driven HJ-P1 can reduce the critical path delay by 23%. 展开更多
关键词 HIERARCHY INTERCONNECT PLACEMENT VLSI circuit wirelength prediction
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A Radial Stub Test Circuit for Microwave Power Devices 被引量:2
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作者 罗卫军 陈晓娟 +3 位作者 梁晓新 马晓琳 刘新宇 王晓亮 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2006年第9期1557-1561,共5页
With the principles of microwave circuits and semiconductor device physics, two microwave power device test circuits combined with a test fixture are designed and simulated, whose properties are evaluated by a paramet... With the principles of microwave circuits and semiconductor device physics, two microwave power device test circuits combined with a test fixture are designed and simulated, whose properties are evaluated by a parameter network analyzer within the frequency range from 3 to 8GHz. The simulation and experimental results verify that the test circuit with a radial stub is better than that without. As an example, a C-band AlGaN/GaN HEMT microwave power device is tested with the designed circuit and fixture. With a 5.4GHz microwave input signal,the maximum gain is 8.75dB,and the maximum output power is 33.2dBm. 展开更多
关键词 radial stub test circuit GAN HEMT
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Tests on the First 500 kV Compact Transmission Line in China 被引量:2
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作者 巩学海 王惠仁 张章奎 《Electricity》 2001年第1期22-27,共6页
The paper deals with the tests on the first 500 kV compact transmission line. The transmission line stretches from Fangshan Substation to Changping Substation nearby Beijing with a length of 83 km. In order to investi... The paper deals with the tests on the first 500 kV compact transmission line. The transmission line stretches from Fangshan Substation to Changping Substation nearby Beijing with a length of 83 km. In order to investigate the characteristics of the transmission line, many tests were performed on the line before and after its operation. The results indicate that all electrical parameters are perfectly identical to the design. 展开更多
关键词 compact transmission line overvoltage switching surge parameters
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Nonlinear Auto-Companding Method for Behavioral Modeling of Switched-Current Circuits
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作者 王伟 曾璇 +2 位作者 陶俊 苏仰峰 唐璞山 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第12期1254-1261,共8页
A wavelet collocation method with nonlinear auto companding is proposed for behavioral modeling of switched current circuits.The companding function is automatically constructed according to the initial error distri... A wavelet collocation method with nonlinear auto companding is proposed for behavioral modeling of switched current circuits.The companding function is automatically constructed according to the initial error distribution obtained through approximating the input output function of the SI circuit by conventional wavelet collocation method.In practical applications,the proposed method is a general purpose approach,by which both the small signal effect and the large signal effect are modeled in a unified formulation to ease the process of modeling and simulation.Compared with the published modeling approaches,the proposed nonlinear auto companding method works more efficiently not only in controlling the error distribution but also in reducing the modeling errors.To demonstrate the promising features of the proposed method,several SI circuits are employed as examples to be modeled and simulated. 展开更多
关键词 wavelet collocation method behavioral modeling switched current circuits nonlinear auto companding
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架空输电线路应用摄影测量技术分析 被引量:1
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作者 王骏 《科技资讯》 2009年第2期141-141,共1页
随着摄影测量技术的成熟和发展,在架空输电线路工程中的应用摄影测量技术得到广泛重视。本文对摄影测量在架空输电线路中的应用现状进行分析和总结,并对其发展趋势提出一点看法。
关键词 架空输电线路 摄影测量 现状 展望
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Mechanical analysis of transmission lines based on linear sliding cable element
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作者 刘云 钱振东 夏开全 《Journal of Southeast University(English Edition)》 EI CAS 2013年第4期436-440,共5页
In order to study the sliding characteristics when the cable structures are connected with other rods, a string of sliding cable dements (SCE) consisting of one active threenode SCE passing through the sliding point... In order to study the sliding characteristics when the cable structures are connected with other rods, a string of sliding cable dements (SCE) consisting of one active threenode SCE passing through the sliding point and multiple inactive two-node SCEs is put forward. Based on the updated Lagrangian formulation, the geometric nonlinear stiffness matrix of the three-node straight sliding cable dement is deduced. The examples about two-span and three-span continuous cable structures are studied to verify the effectiveness of the derived SCE. Comparing the cable tension of SCE with the existing research results, the calculating results show that the error is less than 1%. The sliding characteristics should be considered in practical engineering because of the obvious difference between the cable tension of the SCE and that of the cable element without considering sliding characteristics. 展开更多
关键词 transmission line sliding cable element updated Lagrangian formulation geometric nonlinear
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Involvement of genes required for synaptic function in aging control in C.elegans
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作者 沈露露 汪洋 王大勇 《Neuroscience Bulletin》 SCIE CAS CSCD 2007年第1期21-29,共9页
Objective To identify new genes required for neurosecretory control of aging in C. elegans. Methods In view of the importance of nervous system in aging regulation, we performed the screen for genes involved in the ag... Objective To identify new genes required for neurosecretory control of aging in C. elegans. Methods In view of the importance of nervous system in aging regulation, we performed the screen for genes involved in the aging regulation from genetic loci encoding synaptic proteins by lifespan assay and accumulation of lipofuscin autofluorescence. We further investigated the dauer formation phenotypes of their corresponding mutants and whether they were possibly up-regulated by the insulin-like signaling pathway. Results The genetic loci of unc-10, syd-2, hlb-1, dlk-1, mkk-4, scd- 2, snb-1, ric-4, nrx-1, unc-13, sbt-1 and unc-64 might be involved in the aging control. In addition, functions of unc-10, syd-2, hlb-1, dlk-1, mkk-4, scd-2, snb-1, ric-4 and nrx-1 in regulating aging may be opposite to those of unc-13, sbt-1 and unc-64. The intestinal autofluorescence assay further indicated that the identified long-lived and short-lived mutants were actually due to the suppressed or accelerated aging. Among the identified genes, syd-2, hlb-1, mkk-4, scd-2, snb-1, ric-4 and unc-64 were also involved in the control of dauer formation. Moreover, daf-2 mutation positively regulated the expression of syd-2 and hlb-1, and negatively regulated the expression of mkk-4, nrx-1, ric-4, sbt-1, rpm-1, unc-10, dlk- 1 and unc-13. The daf-16 mutation positively regulated the expression of syd-2 and hlb-1, and negatively regulated the expression of mkk-4, nrx-1, sbt-1, rpm-1, unc-10, dlk-1 and unc-13. Conclusion These data suggest the possibly important status of the synaptic transmission to the animal' s life-span control machinery, as well as the dauer formation control. 展开更多
关键词 AGING NEUROTRANSMISSION SYNAPSE dauer formation insulin pathway C. elegans
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Resistivity Instability in Polysilicon Resistors Under Metal Interco-nnects and Its Suppression by Compensating Ion Implantation
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作者 余宁梅 高勇 陈治明 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2001年第4期511-515,共5页
The resistivity instability of the boron-doped polysilicon resistors being a line resistance element of ICs is within the range of several kΩ's,especially when our running the underneath metal interconnects.Polys... The resistivity instability of the boron-doped polysilicon resistors being a line resistance element of ICs is within the range of several kΩ's,especially when our running the underneath metal interconnects.Polysilicon resistors have been fabricated under various processing conditions as well as some electrical and crystallographic characteristics have been obtained.It is shown the resistivity instability mainly results from the variational carrier mobility.By analyzing the Seto's model,the barrier height and trapped charge density are observed reducing under the Al over layer.Therefore,the resistance instability is also caused by both the charge trapping/detrapping occurring at polysilicon grain boundaries and the resultant variation in the potential barrier height.The formation of high-stability polysilicon resistors in the range of several kΩ's has been decided by compensating the ion implantation,which makes the charge trapping/detrapping at the grain boundary less susceptible to the hydrogen annealing. 展开更多
关键词 POLYSILICON INTERCONNECT
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A Novel SPIC with a Simple APFC Circuit
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作者 韩磊 叶星宁 +1 位作者 成民 杨洪强 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第8期813-816,共4页
A novel SPIC(smart power IC) with a simple APFC(active power factor correction) circuit on one chip is proposed.The V _ bus (bus voltage) with high power factor falls from 600V to 400V by using a delay circuit in w... A novel SPIC(smart power IC) with a simple APFC(active power factor correction) circuit on one chip is proposed.The V _ bus (bus voltage) with high power factor falls from 600V to 400V by using a delay circuit in which a long channel length NMOS is used to substitute a large biasing resistance to save chip area.The lower V _ bus results in a smaller R _ on (on-resistance) of power switcher,which reduces the power loss of the power devices,improves the efficiency of the circuit,and reduces the cost of circuits.An integrated high voltage over voltage protect circuit is also designed in the circuits.Theory and simulations both prove the correctness and availability of the design. 展开更多
关键词 APFC SPIC duty cycle bus voltage
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