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Fabrication and Chemical Crosslinking of Electrospun Trans-polyisoprene Nanofiber Nonwoven

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Chinese Journal of Polymer Science 2016年第6期34卷 697-708页

作者： hua-rong nie chao wang 贺爱华 Shandong Provincial Key Laboratory of Olefin Catalysis and Polymerization Key Laboratory of Rubber-Plastics (Ministry of Education) School of Polymer Science and Engineering Qingdao University of Science and Technology Qingdao 266042 China

In this work, the optimal electrospinning conditions of trans-polyisoprene （TPI） solutions were evaluated nevertheless its lower glass transition temperature than the room temperature. Subsequently, chemical crosslinking of TPI nonwovens was firstly investigated by vulcanizing at high temperatures in the case of the persistence of nanofiber structure. For this purpose, curing agents of TPI were embedded in TPI nanofibers by co-electrospinning, and then a protect layer was coated on TPI nanofibers by filtering gelatin solution going through TPI nonwoven before the vulcanization at 140-160 ℃. The results showed that the vulcanization of TPI fibrous nonwoven at high temperatures did not destroy the fiber morphology. Interestingly, TPI fibrous nonwovens after vulcanization showed excellent mechanical properties （N17 MPa of tensile strength） that could be comparable to or even higher than that of some bulk rubber materials.

关键词： Trans-1,4-polyisoprene Electrospun nanofibers Gelatin Vulcanization Chemical crosslinking.

Multiplicity results for the unstirred chemostat model with general response functions

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Science China Mathematics 2013年第10期56卷 2035-2050页

作者： nie hua WU Jianhua College of Mathematics and Information Science Shaanxi Normal University

We investigate the multiplicity of positive steady state solutions to the unstirred chemostat model with general response functions. It turns out that all positive steady state solutions to this model lie on a single smooth solution curve, whose properties determine the multiplicity of positive steady state solutions. The key point of our analysis is to study the ＂turning points＂ on this positive steady state solution curve, and to prove that any nontrivial solution to the associated linearized problem is one of sign by constructing a suitable test function. The main tools used here include bifurcation theory, monotone method, mountain passing lemma and Sturm comnarison theorem.

关键词： chemostat general response function multiplicity bifurcation theory Sturm comparison theorem

Fractionated and Confined Crystallization of Polybutene-1 in Immiscible Polypropylene/Polybutene-1 Blends

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Chinese Journal of Polymer Science 2018年第7期36卷 859-865页

作者： Yao Xu Chen-Guang Liu hua-Rong nie Ai-hua He Shandong Provincial Key Laboratory of Olefin Catalysis and Polymerization Key Laboratory of Rubber-Plastics (Ministry of Education) School of Polymer Science and Engineering Qingdao University of Science and Technology

In this work, the crystallization of immiscible polypropylene （PP）/polybutene-1 （PB） blends, in particular the effect of crystal morphology of PP （HTC, high Tm component） on the subsequent crystallization behavior of PB （LTC, low Tm component） was studied. Herein, we firstly indicated that PP/PB blends were not completely compatible but characterized as the LCST-like phase diagram above the melting temperature of PP. Crystallization of PP at different crystallization temperatures brought about different PP crystal morphologies and PB was segregated and confined at different locations. Much larger-sized domain of PB component appeared in PP spherulites resulting from the effects of non-negligible phase separation and the slower PP crystallization rate as PP crystallized at high temperature. As temperature continued to fall below Tm of PB, the fractionated and confined crystallization of PB occurred in the framework of PP spherulites, reflected by the decreased crystallization temperature （To） of PB and the formation of form I＇ beside form II. Notably, if PP previously crystallized at high Tc, fractionated crystallization of PB became predominant and confined crystallization of PB became weak due to the much wider droplet-size distribution of PB domains.

关键词： Polypropylene Polybutene Confined crystallization Morphology

Asymptotic Behavior on a Competition Model Arising from an Unstirred Chemostat

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Acta Mathematicae Applicatae Sinica 2006年第2期22卷 257-264页

作者： hua nie Jian-hua Wu College of Mathematics and Information Science Shaanxi Normal University Xi'an 710062 China

This paper is concerned with the unstirred chemostat model with two-species and one non-reproducing resource. The global attractivity of the positive steady-state solutions of the original system is established. Moreo... 详细信息

关键词： Chemostat steady-state solution monotone method global attractivity

Research Data Management Implementation at Peking University Library:Foster and Promote Open Science and Open Data

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Data Intelligence 2021年第1期3卷 189-204页

作者： hua nie Pengcheng Luo Ping Fu Peking University Library Beijing 100871China Central Washington University Library 400 E.University WayEllensburg WA 98926USA

Research Data Management(RDM)has become increasingly important for more and more academic *** the Peking University Open Research Data Repository(PKU-ORDR)project as an example,this paper will review a library-based university-wide open research data repository project and related RDM services implementation process including project kickoff,needs assessment,partnerships establishment,software investigation and selection,software customization,as well as data curation services and *** the review,some issues revealed during the stages of the implementation process are also discussed and addressed in the paper such as awareness of research data,demands from data providers and users,data policies and requirements from home institution,requirements from funding agencies and publishers,the collaboration between administrative units and libraries,and concerns from data providers and *** significance of the study is that the paper shows an example of creating an Open Data repository and RDM services for other Chinese academic libraries planning to implement their RDM services for their home *** authors of the paper have also observed since the PKU-ORDR and RDM services implemented in 2015,the Peking University Library(PKUL)has helped numerous researchers to support the entire research life cycle and enhanced Open Science(OS)practices on campus,as well as impacted the national OS movement in China through various national events and activities hosted by the PKUL.

关键词： Research data management implementation Open Science Open Data Research life cycle Data sharing and reuse

牙周炎对雌激素缺乏小鼠骨组织及肠道色氨酸代谢影响的研究

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中华口腔医学杂志 2024年第4期59卷 354-363页

作者：魏媛王南南王敏钱俊聂华葛叡扬廖文正闫福华南京大学医学院附属口腔医院·南京市口腔医院牙周病科南京大学口腔医学研究所南京210008

目的研究雌激素缺乏背景下,牙周炎对骨组织和肠道色氨酸代谢的影响。方法将32只雌性C57BL6/J小鼠根据随机数字表法随机分为4组(每组8只):假手术组(Sham组);假手术牙周炎组(Sham_Lig组);去卵巢组(Ovx组);去卵巢牙周炎组(Ovx_Lig组)。Sham... 详细信息

目的研究雌激素缺乏背景下,牙周炎对骨组织和肠道色氨酸代谢的影响。方法将32只雌性C57BL6/J小鼠根据随机数字表法随机分为4组(每组8只):假手术组(Sham组);假手术牙周炎组(Sham_Lig组);去卵巢组(Ovx组);去卵巢牙周炎组(Ovx_Lig组)。Sham_Lig组与Ovx_Lig组小鼠术后4周,以5-0号丝线结扎双侧上颌第二磨牙诱导牙周炎。丝线结扎8周后对4组小鼠实施安乐死,取材小鼠股骨、胫骨、下颌骨及颅骨样本行显微CT(micro-CT)扫描,并检测样本骨密度、骨体积分数(BV/TV)、骨小梁数量(Tb.N)、骨小梁厚度(***)和骨小梁分离度(***)。收集4组小鼠盲肠内容物,利用16S rRNA基因测序检测肠道菌群的组成,通过液相色谱-质谱法检测肠道中的色氨酸及其代谢物的含量,并对肠道菌群相对丰度水平与色氨酸代谢物含量行相关性分析。结果Ovx_Lig组小鼠股骨骨密度[(82.23±3.97)mg/cm^(3)]、BV/TV[(9.25±1.37)%]和***[(70.95±5.70)μm]均显著低于Ovx组[分别为(96.30±3.76)mg/cm^(3)(P=0.004)、(14.45±1.55)%(P=0.022)和(87.58±8.02)μm(P<0.001)]。肠道菌群基于Bray-Curtis距离的β多样性分析显示,Ovx_Lig组小鼠肠道菌群与Ovx组分群明显。线性判别分析效应量显示,另枝菌属为Ovx_Lig组显著差异菌属。Ovx_Lig组另枝菌属的相对丰度[(0.42±0.14)%]显著高于Ovx组[(0.17±0.05)%](t=4.45,P<0.001)。色氨酸代谢分析显示,Ovx_Lig组小鼠肠道内犬尿酸的含量[(531.12±158.60)ng/g]显著高于Ovx组[(400.42±57.96)ng/g](t=2.19,P=0.046),吲哚-3-甲醛的含量[(383.37±144.06)ng/g]显著低于Ovx组[(701.72±141.93)ng/g](t=4.45,P<0.001)。相关性分析显示另枝菌属的相对丰度与犬尿酸呈正相关(r=0.32,P=0.088),与吲哚-3-甲醛呈负相关(r=-0.32,P=0.088)。结论小鼠雌激素缺乏背景下,牙周炎可导致小鼠股骨骨质破坏,其机制可能与肠道另枝菌属及色氨酸代谢物犬尿酸和吲哚-3-甲醛有关。

关键词：牙周炎骨质疏松,绝经后肠道菌群骨代谢色氨酸代谢

Innovative Design and Performance Evaluation of a High-speed Bionic Mechanical Leg

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Journal of Bionic Engineering 2015年第3期12卷 352-360页

作者： hua nie Ronglei Sun Chaoke Guo Guohua Qin Huiyang Yu State Key Lab of Digital Manufacturing Equipment and Technology Huazhong University of Science and Technology Wuhan 430070 China

For most legged robots the drive-motors are mounted on the joints of legs, which increase leg＇s mass and rotary inertia. When mounted on legs, the drive-motor has to rotate clockwise and anticlockwise periodically to swing a leg back and forth. Larger inertia of the leg, as well as the ever-changing status of frequent acceleration and deceleration of the motors, limits the moving speed of the legged robots. This article proposes an improved mechanical design to overcome such problems. All the drive-motors are installed on the robot body to reduce the rotary inertia of the legs. Then a crank-rocker mechanism is used to transform continuous rotation of motors to back and forth motion of the leg. With this scheme, the motor may reach higher rotation speed since it drives a lighter leg with no change of the rotation direction. In addition, an elastic tendon is attached to the ankle to reduce the pulse stress on the leg. Kinematics and dynamics analysis demonstrates that the new design enlarges end-workspace, reduces driving torque and increases ground reaction force, which means the new robot has lager stride and higher swing frequency of leg to achieve faster moving.

关键词： high-speed mechanical design bionic leg dynamics

Control of a Cheetah Robot in Passive Bounding Gait

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Journal of Bionic Engineering 2016年第2期13卷 283-291页

作者： hua nie Ronglei Sun Liya Hu Zhendong Su Wenqiang Hu State Key Laboratory of Digital Manufacturing Equipment and Technology School of Mechanical Science and Engineering Huazhong University of Science and Technology Wuhan 430074 China Tongji Medical College Huazhong University of Science and Technology Wuhan 430074 China

Passive dynamics is always one of research emphases of the legged robots. Studies have proved that cheetah robot could achieve stably passive bounding motion under proper initial conditions in the ideal case. However, the actual robot must have energy dissipation because of friction and collision compared with the theoretical model. This paper aims to propose a control method that can drive the cheetah robot running in passive bounding gait. First, a sagittal-plane model with a rigid torso and two compliant legs is introduced to capture the dynamics of robot bounding. Numerical return map studies of the bounding model reveal that there exists a large variety of passively cyclic bounding motions （fixed points）. Based on the distribution law of fixed points, an open-loop control method including touchdown angle control strategy and leg length control strategy is put forward. At last, prototype of the cheetah robot is designed and manufactured, and locomotion experiment are carried out. The experiment results show that the cheetah robot can achieve a stable bounding motion at different speeds with the proposed control method.

关键词： cheetah robot passive dynamics control bounding gait

Differential Polymorphic Transformation Behavior of Polybutene-1 with Multiple Isotactic Sequences

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Chinese Journal of Polymer Science 2020年第2期38卷 164-173,I0007页

作者： Ya-Ping Ma Wei-Ping Zheng Chen-Guang Liu hua-Feng Shao hua-Rong nie Ai-hua He Shandong Provincial Key Laboratory of Olefin Catalysis and Polymerization Key Laboratory of Rubber-Plastics (Ministry of Education) Qingdao University of Science and Technology

For the solid-solid transformation from form Ⅱ to form Ⅰ of isotactic polybutene-1(iPB),the temperature dependence of form Ⅰ nucleation and growth was deemed to control the transformation ***,the relationship between formⅠ formation and form Ⅱ disappearance in the transformation process is not *** this work,the spontaneous crystal transformation from form Ⅱ to Ⅰ of iPB with 81 mol%mmmm sequence concentration is studied firstly by tracking the two processes,the decay of form Ⅱ and the yielding of form Ⅰ in a wide range of temperature spanning from 0℃ to 50℃ and in a long transformation time ranging from 5 min to 65 days with in situ FTIR and *** the literature reports,the decay rate of form Ⅱ is firstly found to be lower than the yielding rate of form Ⅰ at all studied temperatures,especially at low transition *** is attributed to the amorphous chains which locate near crystal lamella participating into the nucleation of form Ⅱ.The regular chain folding and growth of i PB form Ⅰ from amorphous chains containing short isotactic sequences also lead to an increase in crystallinity of form Ⅰ compared with that of initial form Ⅱ crystallized at 60℃.An increase in the annealing temperature results in decrease in crystallinity and increase in lamellae thickness of i PB formⅠ.

关键词： Polybutene-1 Polymorphic transformation Isotactic sequence Crystallinity Lamellae thickness