In the paper, we present a detailed analysis of the takeoff mechanics of fruitflies which perform voluntary takeoff flights. Wing and body kinematics of the insects during takeoff were measured using Based on the meas...In the paper, we present a detailed analysis of the takeoff mechanics of fruitflies which perform voluntary takeoff flights. Wing and body kinematics of the insects during takeoff were measured using Based on the measured data, high-speed video techniques. inertia force acting on the insect was computed and aerodynamic force and moment of the wings were calculated by the method of computational fluid dynamics. Subtracting the aerodynamic force and the weight from the inertia force gave the leg force. The following has been shown. In its voluntary takeoff, a fruitfly jumps during the first wingbeat and becomes airborne at the end of the first wingbeat. When it is in the air, the fly has a relatively large ＂initial＂ pitch-up rotational velocity （more than 5 000~/s） resulting from the jumping, but in about 5 wingbeats, the pitch-up rotation is stopped and the fly goes into a quasi-hovering flight. The fly mainly uses the force of jumping legs to lift itself into the air （the force from the flapping wings during the jumping is only about 5%-10% of the leg force）. The main role played by the flapping wings in the takeoff is to produce a pitch-down moment to nullify the large ＂initial＂ pitch-up rotational velocity （otherwise, the fly would have kept pitching-up and quickly fallen down）.展开更多
The thermal behavior and non-isothermal decomposition kinetics of 1-amino-1-hydrazino-2,2-dinitro-ethylene potassium salt[K（AHDNE）] were studied under the non-isothermal conditions by different scanning calorimeter...The thermal behavior and non-isothermal decomposition kinetics of 1-amino-1-hydrazino-2,2-dinitro-ethylene potassium salt[K（AHDNE）] were studied under the non-isothermal conditions by different scanning calorimeter（DSC） method. The thermal behavior of K（AHDNE） presents three exothermic decomposition processes. The kinetic equation of the first thermal decomposition reaction obtained is dα/dT=（1019.63/β）3（1-α）[-ln（1-α）]2/3exp（-1.862× 105/RT）. The self-accelerating decomposition temperature（TSADT） and critical temperature of thermal explosion（Tb） of K（AHDNE） are 162.5 and 171.4 °C, respectively. K（AHDNE） has higher thermal stability than AHDNE.展开更多
This paper uses a 7-degree-of-freedom(7-DOF)manipulator end-effector to research inverse kinematics solution,Three methods are used and compared,including fixing an angle method,the iteration method and the neutral ne...This paper uses a 7-degree-of-freedom(7-DOF)manipulator end-effector to research inverse kinematics solution,Three methods are used and compared,including fixing an angle method,the iteration method and the neutral network method.By comparison,the iteration method is much better because of its high accuracy,fast speed and stabilization,and it does not require calculation of the pseudoinverse of the Jacobian.Thus,this control scheme is well suited for real-time implementation,which is essential if the end-effector trajectory is continuously modified based on sensor's feedback.Finally,using VC++and Microsoft foundation classes(MFC)to achieve the main machine interface.Through verification,the precision meets the requirements of general control system in real-time implementation.展开更多
We present high quality long slit spectra along the major and minor axes out to 1.5 effective radii of the massive galaxy NGC 4636 taken by the Hobby-Eberly Telescope. Using the Fourier Correlation Quotient method, we...We present high quality long slit spectra along the major and minor axes out to 1.5 effective radii of the massive galaxy NGC 4636 taken by the Hobby-Eberly Telescope. Using the Fourier Correlation Quotient method, we measured the stellar line-of-sight velocity distribution along the axes. Furthermore, six Lick/IDS indices （Hβ, Mgb, Fe5015, Fe5270, Fe5335, Fe5406） are derived from the clean spectrum. By comparing the measured absorption line strengths with the predictions of Simple Stellar Population （SSP） models, we derived ages, total metallicity and a abundance profiles of the galaxy. This galaxy presents old and [α/Fe] overabundant stellar populations. Indeed, using the SSP model, we obtained the broadband color profiles. The theoretical colors match well with the measured colors and present red sharp peaks at the galaxy center. The sharp peaks of the colors are mainly shaped by the high metallicity in the galaxy＇s center. Interestingly, the galaxy has steep negative metaUicity gradients, but the trend flattens outwards. This result likely suggests that the center and outer regions of the galaxy formed through different formation processes.展开更多
In this paper, a typical 3-degree of freedom （3- DOF） translational parallel kinematic machine （PKM） is studied and analyzed whose tool platform has only translations along X-, Y- and Z-axes. It consists of three ...In this paper, a typical 3-degree of freedom （3- DOF） translational parallel kinematic machine （PKM） is studied and analyzed whose tool platform has only translations along X-, Y- and Z-axes. It consists of three limbs, each of which have arm and forearm with prismatic- revolute-revolute-revolute （PRRR）joints. Inverse kine- matics analysis is carried out to find the slider coordinates and joint angles for a given position of tool platform. Stiffness modeling is done based on the compliance matrices of arm and forearm of each limb. Using the stiffness modeling the variations of minimum and max- imum translational stiffness in the workspaee are analyzed. For various architectural parameters of the 3-DOF PKM the tendency of variations on the minimum and maximum stiffness over the entire workspace is studied; and also the deflections of the tool platform along X, Y, and Z directions with respect to various forces are presented.展开更多
通过皮下注射花生粗蛋白的致敏方式,建立Balb/c小鼠花生过敏模型,探讨食物过敏的发病机制.将16只Balb/c小鼠(雌性)分为PBS对照组和模型组,利用伊红苏木精(haematoxylin and eosin,H&E)染色,用透射电镜观察小鼠肠道炎症和肠绒毛病理...通过皮下注射花生粗蛋白的致敏方式,建立Balb/c小鼠花生过敏模型,探讨食物过敏的发病机制.将16只Balb/c小鼠(雌性)分为PBS对照组和模型组,利用伊红苏木精(haematoxylin and eosin,H&E)染色,用透射电镜观察小鼠肠道炎症和肠绒毛病理变化,发现花生过敏模型组较PBS对照组可见小肠黏膜水肿和炎症细胞浸润,组肠微绒毛严重损伤;通过伊文思蓝尾静脉注射,模型组中小鼠足部出现明显蓝色,而对照组无明显变化;模型组腹腔灌洗液细胞相对PBS对照组炎症细胞数目显著增加,主要以嗜酸性粒细胞、淋巴细胞和肥大细胞为主,且肥大细胞活化状态明显;酶联免疫吸附法检测发现,血清中IgE、IL-4、IL-5、IL-6和组胺的水平及腹腔上清液组胺的水平,模型组明显高于对照组(P<0.05),IgG2a和IFN-γ的水平模型显著低于PBS对照组(P<0.01).花生模型组较对照组出现一系列的过敏病理变化,为开发治疗花生过敏药物提供了良好的动物模型.展开更多
基金supported by the National Natural Science Foundation of China(11232002)the 111 Project(B07009)
文摘In the paper, we present a detailed analysis of the takeoff mechanics of fruitflies which perform voluntary takeoff flights. Wing and body kinematics of the insects during takeoff were measured using Based on the measured data, high-speed video techniques. inertia force acting on the insect was computed and aerodynamic force and moment of the wings were calculated by the method of computational fluid dynamics. Subtracting the aerodynamic force and the weight from the inertia force gave the leg force. The following has been shown. In its voluntary takeoff, a fruitfly jumps during the first wingbeat and becomes airborne at the end of the first wingbeat. When it is in the air, the fly has a relatively large ＂initial＂ pitch-up rotational velocity （more than 5 000~/s） resulting from the jumping, but in about 5 wingbeats, the pitch-up rotation is stopped and the fly goes into a quasi-hovering flight. The fly mainly uses the force of jumping legs to lift itself into the air （the force from the flapping wings during the jumping is only about 5%-10% of the leg force）. The main role played by the flapping wings in the takeoff is to produce a pitch-down moment to nullify the large ＂initial＂ pitch-up rotational velocity （otherwise, the fly would have kept pitching-up and quickly fallen down）.
基金Supported by the National Natural Science Foundation of China(No.20803058)the Shaanxi Provincial Science Program Foundation, China(No.2011kjxx31)the Education Committee Foundation of Shaanxi Province, China(Nos.2010JK881,12JK0636)
文摘The thermal behavior and non-isothermal decomposition kinetics of 1-amino-1-hydrazino-2,2-dinitro-ethylene potassium salt[K（AHDNE）] were studied under the non-isothermal conditions by different scanning calorimeter（DSC） method. The thermal behavior of K（AHDNE） presents three exothermic decomposition processes. The kinetic equation of the first thermal decomposition reaction obtained is dα/dT=（1019.63/β）3（1-α）[-ln（1-α）]2/3exp（-1.862× 105/RT）. The self-accelerating decomposition temperature（TSADT） and critical temperature of thermal explosion（Tb） of K（AHDNE） are 162.5 and 171.4 °C, respectively. K（AHDNE） has higher thermal stability than AHDNE.
基金Shandong Province Science and Technology Development Plan(No. 2011SJGZ02)Shandong University of Science and Technology Graduate Innovation Fund(No.YCA120355)
文摘This paper uses a 7-degree-of-freedom(7-DOF)manipulator end-effector to research inverse kinematics solution,Three methods are used and compared,including fixing an angle method,the iteration method and the neutral network method.By comparison,the iteration method is much better because of its high accuracy,fast speed and stabilization,and it does not require calculation of the pseudoinverse of the Jacobian.Thus,this control scheme is well suited for real-time implementation,which is essential if the end-effector trajectory is continuously modified based on sensor's feedback.Finally,using VC++and Microsoft foundation classes(MFC)to achieve the main machine interface.Through verification,the precision meets the requirements of general control system in real-time implementation.
基金Supported by the National Natural Science Foundation of China rant No. 10821061the National Basic Research Program of China (Grant Nos. 11033008 nd 2007CB815406)the pport of the Chinese Academy of Sciences (Grant No. KJCX2-YW-T24)
文摘We present high quality long slit spectra along the major and minor axes out to 1.5 effective radii of the massive galaxy NGC 4636 taken by the Hobby-Eberly Telescope. Using the Fourier Correlation Quotient method, we measured the stellar line-of-sight velocity distribution along the axes. Furthermore, six Lick/IDS indices （Hβ, Mgb, Fe5015, Fe5270, Fe5335, Fe5406） are derived from the clean spectrum. By comparing the measured absorption line strengths with the predictions of Simple Stellar Population （SSP） models, we derived ages, total metallicity and a abundance profiles of the galaxy. This galaxy presents old and [α/Fe] overabundant stellar populations. Indeed, using the SSP model, we obtained the broadband color profiles. The theoretical colors match well with the measured colors and present red sharp peaks at the galaxy center. The sharp peaks of the colors are mainly shaped by the high metallicity in the galaxy＇s center. Interestingly, the galaxy has steep negative metaUicity gradients, but the trend flattens outwards. This result likely suggests that the center and outer regions of the galaxy formed through different formation processes.
文摘目的探讨新生儿持续肺动脉高压(persistent pulmonary hypertension of newborn,PPHN)患儿血清人CXC型趋化因子配体8(C-X-C motif chemokine ligand 8,CXCL8)、CXCL12与一氧化氮吸入治疗临床转归的关系。方法选择2021-08/2023-05月作者医院收治并给予一氧化氮吸入治疗的PPHN患儿135例为研究对象。根据患儿出院时临床转归结局分为死亡组(n=32)和存活组(n=103)。比较两组PPHN患儿血清CXCL8、CXCL12水平。单因素及多因素Logistic回归模型分析接受一氧化氮吸入治疗PPHN患儿临床转归的影响因素。受试者工作特征(receiver operating characteristic,ROC)曲线分析血清CXCL8、CXCL12对接受一氧化氮吸入治疗PPHN患儿临床转归的预测价值。结果死亡组患儿血清CXCL8、CXCL12水平显著高于存活组(P均<0.05)。多因素Logsitic回归分析结果显示,血清CXCL8水平升高、血清CXCL12水平升高、早产、出生时Apgar评分0~3分、合并并发症是接受一氧化氮吸入治疗的PPHN患儿死亡的危险因素,肺表面活性物质应用、吸入一氧化氮早期反应则是保护因素(P<0.05)。ROC曲线分析结果显示,血清CXCL8、CXCL12联合检测对接受一氧化氮吸入治疗的PPHN患儿死亡预测的曲线下面积(area under the curve,AUC)为0.828,大于血清CXCL8、CXCL12单独检测(AUC分别为0.762、0.714)。结论PPHN患儿血清CXCL8、CXCL12水平升高与接受一氧化氮治疗的不良临床转归有关,且CXCL8、CXCL12水平升高是PPHN患儿死亡的危险因素。CXCL8、CXCL12联合检测对接受一氧化氮治疗PPHN患儿死亡具有较高的预测价值。
文摘In this paper, a typical 3-degree of freedom （3- DOF） translational parallel kinematic machine （PKM） is studied and analyzed whose tool platform has only translations along X-, Y- and Z-axes. It consists of three limbs, each of which have arm and forearm with prismatic- revolute-revolute-revolute （PRRR）joints. Inverse kine- matics analysis is carried out to find the slider coordinates and joint angles for a given position of tool platform. Stiffness modeling is done based on the compliance matrices of arm and forearm of each limb. Using the stiffness modeling the variations of minimum and max- imum translational stiffness in the workspaee are analyzed. For various architectural parameters of the 3-DOF PKM the tendency of variations on the minimum and maximum stiffness over the entire workspace is studied; and also the deflections of the tool platform along X, Y, and Z directions with respect to various forces are presented.
文摘通过皮下注射花生粗蛋白的致敏方式,建立Balb/c小鼠花生过敏模型,探讨食物过敏的发病机制.将16只Balb/c小鼠(雌性)分为PBS对照组和模型组,利用伊红苏木精(haematoxylin and eosin,H&E)染色,用透射电镜观察小鼠肠道炎症和肠绒毛病理变化,发现花生过敏模型组较PBS对照组可见小肠黏膜水肿和炎症细胞浸润,组肠微绒毛严重损伤;通过伊文思蓝尾静脉注射,模型组中小鼠足部出现明显蓝色,而对照组无明显变化;模型组腹腔灌洗液细胞相对PBS对照组炎症细胞数目显著增加,主要以嗜酸性粒细胞、淋巴细胞和肥大细胞为主,且肥大细胞活化状态明显;酶联免疫吸附法检测发现,血清中IgE、IL-4、IL-5、IL-6和组胺的水平及腹腔上清液组胺的水平,模型组明显高于对照组(P<0.05),IgG2a和IFN-γ的水平模型显著低于PBS对照组(P<0.01).花生模型组较对照组出现一系列的过敏病理变化,为开发治疗花生过敏药物提供了良好的动物模型.
