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Boehmeria nivea var. strigosa (Urticaceae), a new variety from Southwest China
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作者 ZHAO Ying Richard I.MILNE +2 位作者 LI Zhipeng Amos KIPKOECH WU Zengyuan 《广西植物》 CAS CSCD 北大核心 2024年第9期1617-1624,I0001-I0006,共14页
Boehmeria nivea var.strigosa Zeng Y.Wu&Y.Zhao,a new variety of B.nivea(Urticaceae)from Southwest China,is here described based on evidence from morphology and molecular phylogeny.This new variety is mainly charact... Boehmeria nivea var.strigosa Zeng Y.Wu&Y.Zhao,a new variety of B.nivea(Urticaceae)from Southwest China,is here described based on evidence from morphology and molecular phylogeny.This new variety is mainly characterized by its green abaxial leaf blade,partly connate stipules,and densely patent strigose hairs on stems and potioles.The phylogenetic analysis based on rbc L,nrDNA and rbc L+nrDNA datasets,revealed that all individuals of B.nivea var.strigosa formed a monophyletic group.The conservation status of B.nivea var.strigosa is assessed as“Near Threatened”(NT)according to IUCN evaluation criteria.The discovery of this new variety is not only crucial for the taxonomy of ramie,but also provides reference for the exploration and utilization of ramie. 展开更多
关键词 Boehmeria nivea MORPHOLOGY molecular phylogeny new variety Southwest China YUNNAN
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Optical facet coatings for high-performance LWIR quantum cascade lasers atλ∼8.5μm
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作者 MA Yuan LIN Yu-Zhe +5 位作者 WAN Chen-Yang WANG Zi-Xian ZHOU Xu-Yan ZHANG Jin-Chuan LIU Feng-Qi ZHENG Wan-Hua 《红外与毫米波学报》 SCIE EI CAS CSCD 北大核心 2024年第4期497-502,共6页
We report on the performance improvement of long-wave infrared quantum cascade lasers(LWIR QCLs)by studying and optimizing the anti-reflection(AR)optical facet coating.Compared to the Al2O3 AR coat⁃ing,the Y_(2)O_(3)A... We report on the performance improvement of long-wave infrared quantum cascade lasers(LWIR QCLs)by studying and optimizing the anti-reflection(AR)optical facet coating.Compared to the Al2O3 AR coat⁃ing,the Y_(2)O_(3)AR coating exhibits higher catastrophic optical mirror damage(COMD)level,and the optical facet coatings of both material systems have no beam steering effect.A 3-mm-long,9.5-μm-wide buried-heterostruc⁃ture(BH)LWIR QCL ofλ~8.5μm with Y_(2)O_(3)metallic high-reflection(HR)and AR of~0.2%reflectivity coating demonstrates a maximum pulsed peak power of 2.19 W at 298 K,which is 149%higher than that of the uncoated device.For continuous-wave(CW)operation,by optimizing the reflectivity of the Y_(2)O_(3)AR coating,the maximum output power reaches 0.73 W,which is 91%higher than that of the uncoated device. 展开更多
关键词 quantum cascade lasers long-wave infrared optical facet coatings catastrophic optical mirror damage
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Slope displacement prediction based on multisource domain transfer learning for insufficient sample data
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作者 Zheng Hai-Qing Hu Lin-Ni +2 位作者 Sun Xiao-Yun Zhang Yu Jin Shen-Yi 《Applied Geophysics》 SCIE CSCD 2024年第3期496-504,618,共10页
Accurate displacement prediction is critical for the early warning of landslides.The complexity of the coupling relationship between multiple influencing factors and displacement makes the accurate prediction of displ... Accurate displacement prediction is critical for the early warning of landslides.The complexity of the coupling relationship between multiple influencing factors and displacement makes the accurate prediction of displacement difficult.Moreover,in engineering practice,insufficient monitoring data limit the performance of prediction models.To alleviate this problem,a displacement prediction method based on multisource domain transfer learning,which helps accurately predict data in the target domain through the knowledge of one or more source domains,is proposed.First,an optimized variational mode decomposition model based on the minimum sample entropy is used to decompose the cumulative displacement into the trend,periodic,and stochastic components.The trend component is predicted by an autoregressive model,and the periodic component is predicted by the long short-term memory.For the stochastic component,because it is affected by uncertainties,it is predicted by a combination of a Wasserstein generative adversarial network and multisource domain transfer learning for improved prediction accuracy.Considering a real mine slope as a case study,the proposed prediction method was validated.Therefore,this study provides new insights that can be applied to scenarios lacking sample data. 展开更多
关键词 slope displacement multisource domain transfer learning(MDTL) variational mode decomposition(VMD) generative adversarial network(GAN) Wasserstein-GAN
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Time-dependent effects in transient liquid phase bonding of 304L and Cp-Ti using an Ag-Cu interlayer
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作者 Saeed VAZIRIAN Mohammad MOSHKBAR BAKHSHAYESH Ali FARZADI 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2237-2255,共19页
One of the challenges for bimetal manufacturing is the joining process.Hence,transient liquid phase(TLP)bonding was performed between 304L stainless steel and Cp-Ti using an Ag-Cu interlayer with a thickness of 75μm ... One of the challenges for bimetal manufacturing is the joining process.Hence,transient liquid phase(TLP)bonding was performed between 304L stainless steel and Cp-Ti using an Ag-Cu interlayer with a thickness of 75μm for bonding time of 20,40,60,and 90 min.The bonding temperature of 860℃ was considered,which is under the β transus temperature of Cp-Ti.During TLP bonding,various intermetallic compounds(IMCs),including Ti_(5)Cr_(7)Fe_(17),(Cr,Fe)_(2)Ti,Ti(Cu,Fe),Ti_(2)(Cu,Ag),and Ti_(2)Cu from 304L toward Cp-Ti formed in the joint.Also,on the one side,with the increase in time,further diffusion of elements decreases the blocky IMCs such as Ti_(5)Cr_(7)Fe_(17),(Cr,Fe)_(2)Ti,Ti(Cu,Fe)in the 304L diffusion-affected zone(DAZ)and reaction zone,and on the other side,Ti_(2)(Cu,Ag)IMC transformed into fine morphology toward Cp-Ti DAZ.The microhardness test also demonstrated that the(Cr,Fe)_(2)Ti+Ti_(5)Cr_(7)Fe_(17) IMCs in the DAZ on the side of 304L have a hardness value of HV 564,making it the hardest phase.The maximum and minimum shear strength values are equal to 78.84 and 29.0 MPa,respectively.The cleavage pattern dominated fracture surfaces due to the formation of brittle phases in dissimilar joints. 展开更多
关键词 diffusion brazing transient liquid phase bonding dissimilar material joints microstructural evolution mechanical properties grade 2 titanium
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Temperature-Induced Unfolding Pathway of Staphylococcal Enterotoxin B:Insights from Circular Dichroism and Molecular Dynamics Simulation
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作者 LIU Ji ZHANG Shiyu +1 位作者 ZENG Yu DENG Yi 《食品科学》 EI CAS CSCD 北大核心 2024年第18期55-76,共22页
In this study,circular dichroism(CD)and molecular dynamics(MD)simulation were used to investigate the thermal unfolding pathway of staphylococcal enterotoxin B(SEB)at temperatures of 298–371 and 298–500 K,and the re... In this study,circular dichroism(CD)and molecular dynamics(MD)simulation were used to investigate the thermal unfolding pathway of staphylococcal enterotoxin B(SEB)at temperatures of 298–371 and 298–500 K,and the relationship between the experimental and simulation results were explored.Our computational findings on the secondary structure of SEB showed that at room temperature,the CD spectroscopic results were highly consistent with the MD results.Moreover,under heating conditions,the changing trends of helix,sheet and random coil obtained by CD spectral fitting were highly consistent with those obtained by MD.In order to gain a deeper understanding of the thermal stability mechanism of SEB,the MD trajectories were analyzed in terms of root mean square deviation(RMSD),secondary structure assignment(SSA),radius of gyration(R_(g)),free energy surfaces(FES),solvent-accessible surface area(SASA),hydrogen bonds and salt bridges.The results showed that at low heating temperature,domain Ⅰ without loops(omitting the mobile loop region)mainly relied on hydrophobic interaction to maintain its thermal stability,whereas the thermal stability of domain Ⅱ was mainly controlled by salt bridges and hydrogen bonds.Under high heating temperature conditions,the hydrophobic interactions in domain Ⅰ without loops were destroyed and the secondary structure was almost completely lost,while domain Ⅱ could still rely on salt bridges as molecular staples to barely maintain the stability of the secondary structure.These results help us to understand the thermodynamic and kinetic mechanisms that maintain the thermal stability of SEB at the molecular level,and provide a direction for establishing safer and more effective food sterilization processes. 展开更多
关键词 staphylococcal enterotoxin B circular dichroism molecular dynamics simulations temperature-induced unfolding
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Effect of quenching cooling rate on residual stress and microstructure evolution of 6061 aluminum alloy
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作者 HUANG Ke YI You-ping +4 位作者 HUANG Shi-quan HE Hai-lin LIU Jie HUA Hong-en TANG Yun-jian 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2167-2180,共14页
In this study,the cooling rate was manipulated by quenching with water of different temperatures(30,60 and 100℃).Surface and internal residual stresses in the quenched 6061 aluminum alloy samples were measured using ... In this study,the cooling rate was manipulated by quenching with water of different temperatures(30,60 and 100℃).Surface and internal residual stresses in the quenched 6061 aluminum alloy samples were measured using hole-drilling and crack compliance methods,respectively.Then,the processability of the quenched samples was evaluated at cryogenic temperatures.The mechanical properties of the as-aged samples were assessed,and microstructure evolution was analyzed.The surface residual stresses of samples W30℃,W60℃and W100℃is−178.7,−161.7 and−117.2 MPa,respectively along x-direction,respectively;and−191.2,−172.1 and−126.2 MPa,respectively along y-direction.The sample quenched in boiling water displaying the lowest residual stress(~34%and~60%reduction in the surface and core).The generation and distribution of quenching residual stress could be attributed to the lattice distortion gradient.Desirable plasticity was also exhibited in the samples with relatively low quenching cooling rates at cryogenic temperatures.The strengthes of the as-aged samples are 291.2 to 270.1 MPa as the quenching water temperature increase from 30℃to 100℃.Fine and homogeneous β"phases were observed in the as-aged sample quenched with boiling water due to the clusters and Guinier-Preston zones(GP zones)premature precipitated during quenching process. 展开更多
关键词 6061 aluminum alloy residual stress cooling rate cryogenic cooling mechanical properties microstructure evolution
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Tomato detection method using domain adaptive learning for dense planting environments
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作者 LI Yang HOU Wenhui +4 位作者 YANG Huihuang RAO Yuan WANG Tan JIN Xiu ZHU Jun 《农业工程学报》 EI CAS CSCD 北大核心 2024年第13期134-145,共12页
This study aimed to address the challenge of accurately and reliably detecting tomatoes in dense planting environments,a critical prerequisite for the automation implementation of robotic harvesting.However,the heavy ... This study aimed to address the challenge of accurately and reliably detecting tomatoes in dense planting environments,a critical prerequisite for the automation implementation of robotic harvesting.However,the heavy reliance on extensive manually annotated datasets for training deep learning models still poses significant limitations to their application in real-world agricultural production environments.To overcome these limitations,we employed domain adaptive learning approach combined with the YOLOv5 model to develop a novel tomato detection model called as TDA-YOLO(tomato detection domain adaptation).We designated the normal illumination scenes in dense planting environments as the source domain and utilized various other illumination scenes as the target domain.To construct bridge mechanism between source and target domains,neural preset for color style transfer is introduced to generate a pseudo-dataset,which served to deal with domain discrepancy.Furthermore,this study combines the semi-supervised learning method to enable the model to extract domain-invariant features more fully,and uses knowledge distillation to improve the model's ability to adapt to the target domain.Additionally,for purpose of promoting inference speed and low computational demand,the lightweight FasterNet network was integrated into the YOLOv5's C3 module,creating a modified C3_Faster module.The experimental results demonstrated that the proposed TDA-YOLO model significantly outperformed original YOLOv5s model,achieving a mAP(mean average precision)of 96.80%for tomato detection across diverse scenarios in dense planting environments,increasing by 7.19 percentage points;Compared with the latest YOLOv8 and YOLOv9,it is also 2.17 and 1.19 percentage points higher,respectively.The model's average detection time per image was an impressive 15 milliseconds,with a FLOPs(floating point operations per second)count of 13.8 G.After acceleration processing,the detection accuracy of the TDA-YOLO model on the Jetson Xavier NX development board is 90.95%,the mAP value is 91.35%,and the detection time of each image is 21 ms,which can still meet the requirements of real-time detection of tomatoes in dense planting environment.The experimental results show that the proposed TDA-YOLO model can accurately and quickly detect tomatoes in dense planting environment,and at the same time avoid the use of a large number of annotated data,which provides technical support for the development of automatic harvesting systems for tomatoes and other fruits. 展开更多
关键词 PLANTS MODELS domain adaptive tomato detection illumination variation semi-supervised learning dense planting environments
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Role of inclination angle on columnar-to-equiaxed transition in the eutectic Al-5Mg-2Si alloy fabricated by laser powder bed fusion
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作者 YANG Fei-peng WEN Tao +4 位作者 ZHANG Lei WANG Jian-ying HUANG Shi-long JI Shou-xun YANG Hai-lin 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2150-2166,共17页
In this study,the effect of inclination angles relative to the building direction in the additively manufactured eutectic Al-5Mg-2Si alloy was investigated through the laser powder bed fusion(LPBF).The microstructures... In this study,the effect of inclination angles relative to the building direction in the additively manufactured eutectic Al-5Mg-2Si alloy was investigated through the laser powder bed fusion(LPBF).The microstructures and mechanical properties of the Al-5Mg-2Si alloy manufactured with different inclination angles(0°,30°,45°,60°and 90°)were reported and discussed.It is found that the“semicircular”melt pool(MP)in the load bearing face of 0°sample was eventually transformed into“stripe-like”MP in the 90°sample,accompanied by an increased fraction of melt pool boundaries(MPBs).Moreover,the microstructural analysis revealed that the columnar-to-equiaxed transition(CET)of theα-Al grains and eutectic Mg2Si was completed in the 90°sample,which were significantly refined with the average size of 10.6μm and 0.44μm,respectively.It is also found that the 90°sample exhibited good combination of strength and elongation(i.e.yield strength of 393 MPa,ultimate tensile strength of 483 MPa and elongation of 8.1%).The anisotropic mechanical properties were highly associated with the refined microstructures,thermal stress,and density of MPBs.Additionally,the CET driven by inclination angles was attributed to the variation of thermal conditions inside the local MPs. 展开更多
关键词 additive manufacturing aluminium alloys columnar-to-equiaxed transition ANISOTROPY mechanical property
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Effect of thermo-mechanical treatment on microstructure and mechanical properties of wire-arc additively manufactured Al-Cu alloy
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作者 ZHANG Tao QIN Zhen-yang +2 位作者 GONG Hai WU Yun-xin CHEN Xin 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2181-2193,共13页
Wire-arc additive manufacture(WAAM)has great potential for manufacturing of Al-Cu components.However,inferior mechanical properties of WAAM deposited material restrict its industrial application.Inter-layer cold rolli... Wire-arc additive manufacture(WAAM)has great potential for manufacturing of Al-Cu components.However,inferior mechanical properties of WAAM deposited material restrict its industrial application.Inter-layer cold rolling and thermo-mechanical heat treatment(T8)with pre-stretching deformation between solution and aging treatment were adopted in this study.Their effects on hardness,mechanical properties and microstructure were analyzed and compared to the conventional heat treatment(T6).The results show that cold rolling increases the hardness and strengths,which further increase with T8 treatment.The ultimate tensile strength(UTS)of 513 MPa and yield stress(YS)of 413 MPa can be obtained in the inter-layer cold-rolled sample with T8 treatment,which is much higher than that in the as-deposited samples.The cold-rolled samples show higher elongation than that of as-deposited ones due to significant elimination of porosity in cold rolling;while both the T6 and T8 treatments decrease the elongation.The cold rolling and pre-stretching deformation both contribute to the formation of dense and dispersive precipitatedθ′phases,which inhibits the dislocation movement and enhances the strengths;as a result,T8 treatment shows better strengthening effect than the T6 treatment.The strengthening mechanism was analyzed and it was mainly related to work hardening and precipitation strengthening. 展开更多
关键词 wire-arc additive manufacture inter-layer cold rolling thermal-mechanical treatment microstructure mechanical properties strengthening mechanism
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朱熹从“中和旧说”到“中和新说”的思想演变 被引量:2
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作者 孙利 《湘潭大学社会科学学报》 2002年第4期37-39,共3页
在中国传统哲学中 ,已发未发问题又被称为“中和”问题 ,朱熹对这一问题的思考曾经历过从“中和旧说”到“中和新说”的重要变化。在旧说中 ,朱熹主“心为已发 ,性为未发” ,在新说中 ,朱熹主“心贯乎已发未发”。相应地 ,在修养方法上 ... 在中国传统哲学中 ,已发未发问题又被称为“中和”问题 ,朱熹对这一问题的思考曾经历过从“中和旧说”到“中和新说”的重要变化。在旧说中 ,朱熹主“心为已发 ,性为未发” ,在新说中 ,朱熹主“心贯乎已发未发”。相应地 ,在修养方法上 ,朱熹也一改旧说的“先察识后涵养”而为新说的“涵养于未发 ,察识于已发”。正是在从“中和旧说”到“中和新说”这一思想演变过程中 。 展开更多
关键词 朱熹 '中和旧说' '中和新说' '未发' '已发' 思想学变 程学
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美学百年综论
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作者 栾栋 《陕西师范大学学报(哲学社会科学版)》 CSSCI 北大核心 1999年第3期81-88,175,共9页
美学发祥期的突出贡献是形而上美学、美文化哲学和文艺美学的滥筋。美学学科诞生的直接背景是近代西方社会和文史的变化,即人的升迁、神的贬值和科教的兴起。由之构成了美学的三大品格:学术上的跨界、人文上的超升和隐性特质的膨胀。... 美学发祥期的突出贡献是形而上美学、美文化哲学和文艺美学的滥筋。美学学科诞生的直接背景是近代西方社会和文史的变化,即人的升迁、神的贬值和科教的兴起。由之构成了美学的三大品格:学术上的跨界、人文上的超升和隐性特质的膨胀。其人文质地的稚嫩、审美文化的“优根”和主流话语的封闭,瑕瑜互见,利弊杂糅,为走出古典准备着条件。走向现代则是美学的反题。 展开更多
关键词 美学 感性学变 形而上美学 美文化哲学 文艺美学 美学品格
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Dynamic globularization kinetics during hot working of TA15 titanium alloy with colony microstructure 被引量:19
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作者 吴成宝 杨合 +1 位作者 樊晓光 孙志超 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第9期1963-1969,共7页
The dynamic globularization kinetics of TA15(Ti-6Al-2Zr-1Mo-1V) titanium alloy with a colony α microstructure during deformation at temperature range of 860-940 ℃ and strain rate range of 0.01-10 s-1 was quantitat... The dynamic globularization kinetics of TA15(Ti-6Al-2Zr-1Mo-1V) titanium alloy with a colony α microstructure during deformation at temperature range of 860-940 ℃ and strain rate range of 0.01-10 s-1 was quantitatively studied through isothermal compression tests.It is found that the dynamic globularization kinetics and the kinetics rate of TA15 are sensitive to deformation parameters.The dynamic globularized fraction increases with increasing strain,temperature but decreasing strain rate.The variation of globularized fraction with strain approximately follows an Avrami type equation.Using the Avrami type equation,the initiation and completion strains for dynamic globularization of TA15 were predicted to be 0.34-0.59 and 3.40-6.80.The kinetics rate of dynamic globularization increases with strain at first,then decreases.The peak value of kinetics rate,which corresponds to 20%-33% globularization fraction,increases with increasing temperature and decreasing strain rate. 展开更多
关键词 TA15 titanium alloy dynamic globularization KINETICS STRAIN kinetics rate
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Rheological and mechanical properties of wood fiber-PP/PE blend composites 被引量:9
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作者 高华 宋永明 +2 位作者 王清文 韩振 张明丽 《Journal of Forestry Research》 SCIE CAS CSCD 2008年第4期315-318,共4页
For evaluation of the rheological and mechanical properties of highly filled wood plastic composites (WPCs), polypropylene/polyethylene (PP/PE) blends were grafted with maleic anhydride (MAH) to enhance the inte... For evaluation of the rheological and mechanical properties of highly filled wood plastic composites (WPCs), polypropylene/polyethylene (PP/PE) blends were grafted with maleic anhydride (MAH) to enhance the interfacial adhesion between wood fiber and matrix. WPCs were prepared from wood fiber up to 60 wt.% and modified PP/PE was blended by extrusion. The rheological properties were studied by using dynamic measurement. According to the strain sweep test, the linear viscoelastic region of composites in the melt was determined. The result showed that the storage modulus was independent of the strain at low strain region (〈0.1%). The frequency sweep resuits indicated that all composites exhibited shear thinning behavior, and both the storage modulus and complex viscosity of MAH modified composites were decreased comparing to those unmodified. Flexural properties and impact strength of the prepared WPCs were measured according to the relevant standard specifications. The flexural and impact strength of the manufactured composites significantly increased and reached a maximum when MAH dosage was 1.0 wt%, whereas the flexural modulus after an initial decreased, also increased with MAH dosage. The increase in mechanical properties indicated that the presence of anhydride groups enhanced the interracial adhesion between wood fiber and PP/PE blends. 展开更多
关键词 wood fiber PP/PE blends COMPOSITES rheological properties mechanical properties
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“颜元”的诞生——清初学者颜元思想激变过程的重建与诠释 被引量:3
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作者 张循 《中山大学学报(社会科学版)》 CSSCI 北大核心 2019年第5期107-120,共14页
清初思想家颜元的学思历程,在既有研究里呈现为一种标准论述:颜元在39岁之前名叫朱邦良,他在34岁那年获知了自己实为颜氏子,因其父早年为朱氏养子,故他出生后方冒朱姓;随即他的学术面貌也发生了激烈转变,几乎一夜之间就从笃信程、朱变... 清初思想家颜元的学思历程,在既有研究里呈现为一种标准论述:颜元在39岁之前名叫朱邦良,他在34岁那年获知了自己实为颜氏子,因其父早年为朱氏养子,故他出生后方冒朱姓;随即他的学术面貌也发生了激烈转变,几乎一夜之间就从笃信程、朱变成力反程、朱。39岁时,他归宗颜氏,名为颜元。由此他的学术生命大体以34岁为界,分为此前的“朱邦良”和此后的“颜元”两个阶段。从“朱邦良”到“颜元”的转变也成为清初思想史上的一大公案。传统的意见基本认同“颜元”是“朱邦良”顿悟的结果,近来的研究则认为“颜元”是由“朱邦良”逐渐蜕变而成。事实上,通过对他学思历程中若干节点和面向的重建,可以看到早在学变之前,“颜元”就已经站在“朱邦良”的身边;“颜”“朱”两种学术性格始终并存且相互竞争,34岁时的学变并不是“朱邦良”变成了“颜元”,而是“颜元”通过奋斗最终击败了“朱邦良”。对“颜元”的诞生过程尽量真切的了解,是评估在清初震动一时的“颜李学派”的坚实基点。 展开更多
关键词 习斋 “朱邦良” “颜元” 学变 士人文化
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Study on Fruit Quality, Phenological Phases and Shoot Histomorphology of a New Bud Mutant Line, ‘Chuanzao Loquat’ 被引量:5
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作者 梅洛银 廖明安 +4 位作者 任雅君 刘雨 程籍 刘娟 罗丽 《Agricultural Science & Technology》 CAS 2012年第9期1881-1884,共4页
[Objective] This study was to explore the growth characteristics and fruit quality of a new bud mutant line, 'Chuanzao Loquat'. [Method] Paraffin section technique combined with field investigation method were adopt... [Objective] This study was to explore the growth characteristics and fruit quality of a new bud mutant line, 'Chuanzao Loquat'. [Method] Paraffin section technique combined with field investigation method were adopted to conduct com- parative analysis of shoot histomorphology and phenological phases between two Io- quat varieties, 'Chuanzao Loquat' and 'Zaozhong 6'. [Result] 'Chuanzao Loquat' branched out and unfolded leaves about half to a month earlier than 'Zaozhong 6'; both the flowering and fruiting phases of 'Chuanzao Loquat' were three months earlier than a precocious variety, 'Zaozhong 6'; the proportions of epidermis, cortex parenchyma, vascular tissue and medulla were 3.7%, 14.5%, 15.9% and 65.9%, re- spectively, in spdng shoots of 'Chuanzao Loquat', and 3.1%, 42.5%, 6.9% and 47.5%, respectively, in 'Zaozhong 6'. [Conclusion] In terms of phenological phases, 'Chuanzao Loqua' is earlier than 'Zaozhong 6', a currently widely planted precocious variety, and thus is an important germplasm resource of Ioquats. 展开更多
关键词 'Chuanzao Loquat' 'Zaozhong 6' Phenological phases HISTOMORPHOLOGY
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A Dendroclimatic Study of Relic Picea meyeri in Inner Mongolian Steppe 被引量:6
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作者 梁尔源 邵雪梅 +1 位作者 胡玉熹 林金星 《Acta Botanica Sinica》 CSCD 2001年第3期288-294,共7页
Dendroclimatic methods were used to investigate the fundamental relationships between the temperature variables and the growth of climatically relic Picea meyeri Rehd. et Wils. on sandy land of Inner Mongolian gra... Dendroclimatic methods were used to investigate the fundamental relationships between the temperature variables and the growth of climatically relic Picea meyeri Rehd. et Wils. on sandy land of Inner Mongolian grasslands in the Xilin River Basin. The annual mean temperature and accumulated temperature (above 5 ℃, 10 ℃) respectively showed no significant correlation with the spruce growth relative to summer mean temperature, which displayed strong coherence with tree growth ( P <0.01). The mean temperature in May showed significantly negative correlation with spruce growth ( P <0.05). Furthermore, it was revealed that the negative influence of May temperature was due to monthly mean maximum temperature ( T max ) ( P <0.01) other than monthly mean minimum temperature ( T min ) values ( P <0.1), which indicated that the use of T min and T max separately can allow much more insights on the temperate influence. In addition, extreme maximum temperature in May and June might impose the most detrimental influence on tree growth in semi_arid Inner Mongolian grassland. The analysis of the recorded meteorological data demonstrated that the increases in temperature were synchronous with slight decreases in precipitation in the growing season, which suggested that P. meyeri may reduce growth due to temperature_induced drought. On the other hand, the analysis for decadal periods explored that trees appeared to reduce the sensitivity to the warming, and consequently increased sensitivity to rainfall. This may serve as a baseline for more accurate predictions of the potential impacts of altered climate regimes on tree growth. 展开更多
关键词 Picea meyeri DENDROCLIMATOLOGY temperature variables
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Reaction mechanisms of low-grade molybdenum concentrate during calcification roasting process 被引量:5
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作者 甘敏 范晓慧 +6 位作者 陈许玲 吴程骞 季志云 王送荣 汪国靖 邱冠周 姜涛 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2016年第11期3015-3023,共9页
The effects of Ca-based additives on roasting properties of low-grade molybdenum concentrate were studied. The resultsshow that calcium-based additives can react with molybdenum concentrate to form CaSO4 and CaMoO4. T... The effects of Ca-based additives on roasting properties of low-grade molybdenum concentrate were studied. The resultsshow that calcium-based additives can react with molybdenum concentrate to form CaSO4 and CaMoO4. The initial oxidationtemperature of MoS2 is 450℃, while the formation of CaMoO4 and CaSO4 occurs above 500℃. The whole calcification reactionsare nearly completed between 600 and 650℃. However, raising the temperature further helps for the formation of CaMoO4 but isdisadvantageous to sulfur fixing rate and molybdenum retention rate. Calcification efficiency of Ca-based additives follows theorder: Ca(OH)2〉CaO〉CaCO3. With increasing the dosage of Ca(OH)2, the molybdenum retention rate and sulfur-fixing rate rise, butexcessive dosages would consume more acid during leaching process. The appropriate mass ratio of Ca(OH)2 to molybdenumconcentrate is 1:1. When roasted at 650 ℃ for 90 min, the molybdenum retention rate and the sulfur-fixing rate of low-grademolybdenum concentrate reach 100% and 92.92%, respectively, and the dissolution rate of molybdenum achieves 99.12% withcalcines being leached by sulphuric acid. 展开更多
关键词 molybdenum concentrate calcification roasting reaction mechanism thermodynamic analysis phase transformation
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Microstructure,mechanical properties and creep resistance of Mg-(8%-12%)Zn-(2%-6%) Al alloys 被引量:4
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作者 万晓峰 倪红军 +2 位作者 黄明宇 张华丽 孙建华 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2013年第4期896-903,共8页
The microstructural characteristics, mechanical properties and creep resistance of Mg-(8%-12%) Zn-(2%-6%) A1 alloys were investigated to get a better overall understanding of these series alloys. The results indic... The microstructural characteristics, mechanical properties and creep resistance of Mg-(8%-12%) Zn-(2%-6%) A1 alloys were investigated to get a better overall understanding of these series alloys. The results indicate that the microstructure of the alloys ZA82, ZA102 and ZA122 with the mass ratio of Zn to A1 of 4-6 is mainly composed of a-Mg matrix and two different morphologies of precipitates (block τ-Mg32(Al, Zn)49 and dense lamellar ε-Mg51Zn20), the alloys ZA84, ZA104 and ZA124 with the mass ratio of 2-3 contain α-Mg matrix and only block r phases, and the alloys ZA86, ZA106 and ZA126 with the mass ratio of 1-2 consist of a-Mg matrix, block r precipitates, lamellar Ф-Al2Mg5Zn2 eutectics and flocculent β-Mg17Al12 compounds. The alloys studied with the mass ratio of Zn to A1 of 2-3 exhibit high creep resistance, and the alloy ZA124 with the continuous network of r precipitating along grain boundaries shows the highest creep resistance. 展开更多
关键词 Mg-Zn-A1 alloys MICROSTRUCTURE mechanical property creep resistance
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Effect of Yizhikang Powder on Hemorheological Indexes in Dairy Cattle with Retained Placenta 被引量:5
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作者 关辉 谷新利 +3 位作者 罗瑞卿 宋华容 李正国 张飞 《Agricultural Science & Technology》 CAS 2009年第1期111-114,共4页
[ Objective ] The aim of the research was to reveal the mechanism of Yizhikang powder treatment on dairy cattle with retained placenta from the hemorheological perspective. [ Method] Dairy cattle with retained placent... [ Objective ] The aim of the research was to reveal the mechanism of Yizhikang powder treatment on dairy cattle with retained placenta from the hemorheological perspective. [ Method] Dairy cattle with retained placenta were treated with oral administration of Yizhikang powder. And their hemorheological indexes were measured and compared with the corresponding indicators of pre-administration group, healthy group, and control group (sick but untreated).[ Result] There was large decrease amplitude in the indexes (whole blood viscosity, plasma viscosity, whole blood viscosity reduction viscosity, ESR, ESR equation K value, fibrinogen content, platelet aggregation rate, RBC deformability IF value) of treated dairy cattle with retained placenta. By t test, the indexes, except hematocrit, decreased significantly after treatment (P〈0.05) and reached the status of post partum healthy cows. The hemorheological indexes didn't change significantly in the control group before and after treatment. [ Conclusion] Yizhikang powder could significantly improve blood flow state and reduced the occurrence of qi stagnation and blood stasis in perinatal period. 展开更多
关键词 Yizhikang powder Dairy cattle HAEMORHEOLOGY Retained placenta
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PROPERTIES OF BIODEGRADABLE THERMOPLASTIC STARCH 被引量:1
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作者 高建平 王少敏 +1 位作者 王为 于九皋 《Transactions of Tianjin University》 EI CAS 1997年第2期92-96,共5页
Thermoplastic starch is a kind of modified starch produced by mixing starch with additives and processing the mixture in an extruder. The mechanical properties, including tensile strength and elongation at break, biod... Thermoplastic starch is a kind of modified starch produced by mixing starch with additives and processing the mixture in an extruder. The mechanical properties, including tensile strength and elongation at break, biodegradability and rheological properties were studied. Glycerol and urea, to some extent, can both decrease the tensile strength and increase percentage elongation at break, because the former acts as a plasticizer and the latter can break down interactions among starch macromolecules. Thermoplastic starch shows thermoplasticity and its melt behaves as a pseudoplastic liquid at a low shear rate. Its biodegrading extent is slightly higher than that of native starch. The molecular weight of starch displays a decreasing tendency after thermoplastic modification. 展开更多
关键词 thermoplastic starch BIODEGRADABILITY RHEOLOGY mechanical property
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