科学技术与欧洲长笛管体结构的制作工艺研究

科学技术的发展推动了艺术、工艺和科学的相互交融,使得长笛设计与制造方面更加以乐器的声音、演奏家个人特点、区域概念以及当时的音乐风格要求为指导。运用科学技术、声学的物理方法、数学计算法则对乐器管体结构的设计及发音原理进行细致探索和研究,改变了以往简单的制作理念,寻求更加科学的乐器制作法,为之后乐器制造方面的规范化、合理化向前发展起到了铺垫作用。

改变镍钛合金人工食管管体结构在防止脱管中的作用

背景:应用涤纶连接环的设计有效地解决了人工食管研制中发生早期吻合口漏和脱管的难题,实验动物均能长期存活。但带涤纶连接环记忆合金组合式人工食管还存在中晚期脱管的问题未能完全解决。目的:观察改变镍钛合金组合式人工食管的管体结构在防止脱管中的作用。设计、时间及地点:对比观察动物实验,于2007-09/2008-05在广州医学院第二附属医院动物实验室完成。材料:健康小型实验香猪6只由广东省医学实验动物中心提供。带涤沦连接环编织型外层裸管体双层结构镍钛合金组合式人工食管和带涤沦连接环网格型覆膜单管结构镍钛合金组合式人工食管均由北京有色金属研究学院制作提供。方法:通过手术切除一段长约7cm的胸段食管,应用编织型和网格型两种不同管体结构的镍钛合金组合式人工食管替代胸段食管重建食管通道的方法,建立两组实验动物模型,每组3只。主要观察指标:人工食管的位置,新生食管与植入体的结合状况。结果:实验动物均存活超过3个月。网格型组3只(100%)术后3个月内全部出现脱管,脱管发生时间60～68d(平均63d)。编织型组3只(100%)术后3个月内无发生脱管,远近端正常食管无扩张及狭窄,新生食管中间段部分管壁组织向植入体网孔内长入紧密固定。结论:编织型镍钛合金组合式人工食管替代胸段食管后,成功诱导新生食管与管体紧密结合,提示改变镍钛合金组合式人工食管管体结构是防止脱管的有效方法,同时也是解决永久性人工食管脱管这一难题的有效途径。

埋地双排复合式管体结构在SH波作用下的动力分析

以波动理论为基础,采用复变函数法,给出了地下双排复合式管体结构在SH波作用下的解析解。分析了入射波角度、频率变化,管体埋深、内管的厚度变化等参数对管体动应力集中的影响。结果表明:复合式管体内侧的动应力集中峰值明显高于外侧;高频入射时,双排管体在给定距离之间的相互影响较大,动应力集中峰值向邻侧偏移;复合式管体内管越薄,动应力集中峰值越大;垂直入射时,动应力集中峰值受埋深的影响呈周期性变化。

古典主义时期长笛管体结构与指键的发展研究(上)

18世纪中叶长笛管体结构的发展,随着作品风格、器乐演出形式、演奏家的演奏需求逐渐地向前改革推进。优秀的乐器制造家与演奏家的结合,使长笛管体结构的改革更加合理、规范化。指键的增加拓展了长笛的音域,乐器结构的改进提高了演奏性能及操作运用的便捷性。本文将从古典主义时期长笛管体结构、指键发展,以及对长笛管体结构的改革做出重要贡献的乐器制造家进行详细的论述。

Synthesis,crystal structure and photo-physical properties of tris(4-methyl-2,5-diphenylpyridine)iridium for OLED

Organic light-emitting diodes(OLEDs)have important applications in the field of next-generation displays and lighting,and phosphorescent iridium complexes are an important class of electroluminescent phosphorescent materials.In this paper,Ir(bmppy)_(3),tris(4-methyl-2,5-diphenylpyridine)iridium,was synthesized and elvaluted for photo-physical characteristics.Single crystals suitale for X-ray diffraction(XRD)were grown from a mixture solvent of dichloromethane and absolute ethanol.The composition and structur of Ir(bmppy)_(3)were determined by element analysis,NMR spectra and XRD.The complex crystallizes in the monoclinic symmetry with the space group P21/c with a slightly distorted octahedral configuration.As measured by UV-Visible and photoluminescence spectra,Ir(bmppy)_(3) displays a maximum emission at at 527 nm at ambient temperature,a typical green-emitting profile.The complex has potential for application in the OLED industry.

Fabrication of Bottom-Gate and Top-Gate Transparent ZnO Thin Film Transistors

Transparent zinc oxide thin film transistors （ZnO-TFTs） with bottom-gate and top-gate structures were constructed on 50mm silica glass substrates. The ZnO films were deposited by RF magnetron sputtering and SiO2 films served as the gate insulator layer. We found that the ZnO-TFTs with bottom-gate structure have better electrical performance than those with top-gate structure. The bottom-gate ZnO-TFTs operate as an n-channel enhancement mode, which have clear pinch off and saturation characteristics. The field effect mobility, threshold voltage, and the current on/off ratio were determined to be 18.4cm^2/（V ·s）, - 0. 5V and 10^4 , respectively. Meanwhile, the top-gate ZnO-TFTs exhibit n-chan- nel depletion mode operation and no saturation characteristics were detected. The electrical difference of the devices may be due to the different character of the interface between the channel and insulator layers. The two transistors types have high transparency in the visible light region.

Static Induction Devices with Planar Type Buried Gate

Based on the surface-gate and buried-gate structures,a novel buried-gate structure called the planar type buried-gate (PTBG) structure for static induction devices (SIDs) is proposed.An approach to realize a buried-gate type static induction transistor by conventional planar process technology is presented.Using this structure,it is successfully avoided the second epitaxy with a high degree of difficulty and the complicated mesa process in conventional buried gate.The experimental results demonstrate that this structure is desirable for application in power SIDs.Its advantages are high breakdown voltage and blocking gain.

A High Speed IGBT Based on Dynamic Controlled Anode-Short

IGBT with high switching speed is described based on the dynamic controlled anode- short,which incorpo- rates a normally- on,p- MOSFET controlled by the anode voltage indirectly.This device works just as normal when it is in on- state since the channel of the p- MOSFET is pinched- off.During the course of turning off,the channel of the p- MOSFET will prevent the injection of m inorities and introduce an extra access for the carriers to flow to the anode directly,which m akes the IGBT reach its off- state in a shorter time.The simulation results prove that the new structure can reduce the turn- off time by m ore than75 % compared with the normal one under the same break- down voltage and on- state perform ance.Only two more resistors are needed when using this structure,and the re- quirement of the drive circuits is just the sam e as normal.

Low phase noise LC VCO design in CMOS technology

This paper presents the design and the experimental measurements of two complementary metal-oxide-semiconductor (CMOS) LC-tuned voltage controlled oscillators (VCO) implemented in a 0.18 μm 6-metal-layer mixed-signal/RF CMOS technology. The design methodologies and approaches for the optimization of the ICs are presented. The first design is optimized for mixed-signal transistor, oscillated at 2.64 GHz with a phase noise of -93.5 dBc/Hz at 500 kHz offset. The second one optimized for RF transistor, using the same architecture, oscillated at 2.61 GHz with a phase noise of -95.8 dBc/Hz at 500 kHz offset. Under a 2 V supply, the power dissipation is 8 mW, and the maximum buffered output power for mixed-signal and RF transistor are -7 dBm and -5.4 dBm, respectively. Both kinds of oscillators make use of on-chip components only, allowing for simple and robust integration.

GeSi Source/Drain Structure for Suppression of Short Channel Effect in SOI p-MOSFET's

GeSi source/drain structure is purposefully adopted in SOI p MOSFET's to suppress the short channel effect (SCE).The impact of GeSi material (as source only,drain only or both source and drain) on the threshold voltage rolling off and DIBL effect is thoroughly investigated,as well as the influence of the Ge concentration and silicon film thickness.The Ge concentration should be carefully chosen as a tradeoff between the driving current and SCE improvement.The detailed physics is explained.

钢筋混凝土铁路顶管生产及质量控制

本文阐述了钢筋混凝土铁路顶管研制意义 。

An SDN/NFV Based Framework for Management and Deployment of Service Based 5G Core Network

The traffic explosion and the rising of diverse requirements lead to many challenges for traditional mobile network architecture on flexibility, scalability, and deployability. To meet new requirements in the 5 G era, service based architecture is introduced into mobile networks. The monolithic network elements(e.g., MME, PGW, etc.) are split into smaller network functions to provide customized services. However, the management and deployment of network functions in service based 5 G core network are still big challenges. In this paper, we propose a novel management architecture for 5 G service based core network based on NFV and SDN. Combined with SDN, NFV and edge computing, the proposed framework can provide distributed and on-demand deployment of network functions, service guaranteed network slicing, flexible orchestration of network functions and optimal workload allocation. Simulations are conducted to show that the proposed framework and algorithm are effective in terms of reducing network operating cost.

Optical diode behavior of photonic crystal structure with asymmetric Kerr defect

Optical diode behavior of asymmetric one-dimensional photonic crystal with Kerr defect is numerically investigated using nonlinear transfer matrix method. In the linear case, the intensity and the phase of transmitted field are the same for the forward and backward operations. In the nonlinear case, however, the transmitted intensities are much different for the two operations, which display diode characteristic. Physical origin of the anisotropic transmission lies in the different localizations in the defect layer of the two operations.

Cognitive Network Management in Internet of Things

The wide variety of smart embedded computing devices and their increasing number of applications in our daily life have created new op- portunities to acquire knowledge from the physical world anytime and anywhere, which is envisioned as the＂Internet of Things＂ （IoT）. Since a huge number of heterogeneous resources are brought in- to IoT, one of the main challenges is how to effi- ciently manage the increasing complexity of IoT in a scalable, flexNle, and autonomic way. Further- more, the emerging IoT applications will require collaborations among loosely coupled devices, which may reside in various locations of the Inter- net. In this paper, we propose a new IoT network management architecture based on cognitive net- work management technology and Service-Orien- ted Architecture to provide effective and efficient network management of loT.

A Distributed Cell Outage Compensation Mechanism Based on RS Power Adjustment in LTE Networks

To solve the coverage and quality problems caused by cell outage in LTE networks, this paper proposes a distributed self-organizing networks management architecture and a distributed cell outage compensation management mechanism. After detecting and analyzing the outage, a cell outage compensation algorithm based on reference signal power adjustment is proposed. The simulation results show that the proposed mechanism can mitigate the performance degradation significantly. Compared with other algorithms, the proposed scheme is more effective in compensating the coverage gap induced by cell outage

A Review of Approaches and Challenges of BIM Education in Construction Management

As BIM （building information modeling） became the gold standard of the architecture, construction, and engineering industry, lack of skilled BIM professionals is considered one of the major challenges. It is therefore of significant importance that CM （construction management） programs train future construction professionals in the capabilities and advantages of BIM technology. This paper presents the findings of a comprehensive review of the implementation of BIM education in CM programs and summarizes the process of BIM adoption, existing educational approaches, and identified challenges in the implementation process. The information presented in this paper serves as a guide to CM programs that are new to and in the progress of implementing BIM education.

Research on logistics domain-oriented cloud resource management model and architecture

To address the challenges posed by resource shortage or surplus to enterprises productivity,Internet platforms have been widely used,which can balance shortage and surplus in broader environments. However,the existing resource management models lack openness,sharing ability and scalability,which make it difficult for many heterogeneous resources to co-exist in the same system. It is also difficult to resolve the conflicts between distributed self-management and centralized scheduling in the system. This paper analyzes the characteristics of resources in the distributed environment and proposes a new resource management architecture by considering the resource aggregation capacity of cloud computing. The architecture includes a universal resource scheduling optimization model which has been applied successfully in double-district multi-ship-scheduling multi-container-yard empty containers transporting of international shipping logistics. Applications in all these domains prove that this new resource management architecture is feasible and can achieve the expected effect.

The mitochondrial Na^＋/Ca^2＋ exchanger may reduce high glucose-induced oxidative stress and nucleotide-binding oligomerization domain receptor 3 inflammasome activation in endothelial cells

Background The mitochondrial Na^＋/Ca^2＋ exchanger, NCLX, plays an important role in the balance between Ca2. influx and efflux across the mitochondrial inner membrane in endothelial ceils. Mitochondrial metabolism is likely to be affected by the activity of NCLX because Ca^2＋ activates several enzymes of the Krebs cycle. It is currently believed that mitochondria are not only centers of energy produc- tion but are also important sites of reactive oxygen species （ROS） generation and nucleotide-binding oligomerization domain receptor 3 （NLRP3） inflammasome activation. Methods ＆ Results This study focused on NCLX function, in rat aortic endothelial cells （RAECs）, induced by glucose. First, we detected an increase in NCLX expression in the endothelia of rats with diabetes mellitus, which was induced by an injection of streptozotocin. Next, colocalization of NCLX expression and mitochondria was detected using confocal analysis. Suppression of NCLX expression, using an siRNA construct （siNCLX）, enhanced mitochondrial Ca^2＋ influx and blocked efflux induced by glucose. Unexpectedly, silencing of NCLX expression induced increased ROS generation and NLRP3 inflammasome activation. Conclusions These findings suggest that NCLX affects glucose-dependent mitochondrial Ca^2＋ signaling, thereby regulating ROS generation and NLRP3 in- flammasome activation in high glucose conditions. In the early stages of high glucose stimulation, NCLX expression increases to compensate in order to self-protect mitochondrial maintenance, stability, and function in endothelial cells.

Service-Oriented Network Virtualization Architecture for Internet of Things

As a key technology to realize smart services of Internet of Things（IoT）, network virtualization technology can support the network diversification and ubiquity, and improve the utilization rate of network resources. This paper studies the service-ori- ented network virtualization architecture for loT services. Firstly the semantic description method for loT services is proposed, then the resource representation model and resource management model in the environment of network virtualization are presented. Based on the above models, the service-oriented virtual network architecture for loT is established. Finally, a smart campus system is designed and deployed based on the service-oriented virtual network architecture. Moreover, the proposed architecture and models are verified in experiments.

Synergetic Analysis and Possible Control of Vortex-Induced Vibrations in a Fluid-Conveying Steel Catenary Riser

This work aimed to demonstrate possibilities for both active and passive control of the vortex-induced vibration and fatigue life of steel catenary risers via an analysis of the self-organization and evolution of the structural vibration based on synergetic theory. An analysis of the complex interrelated and synergistic relationship between the order parameter and the fast variable was performed, and the master equation of the nodal displacements was established as the order parameter for the evolution of the riser's structural vibration. Passive control methods include modifying the structure's elastic modulus, the internal fluid velocity, the top tension and the structural damping ratio, while an active control involves adjusting the external flow rate. Optimized parameters were obtained by analyzing the non-steady state solution of the master equation. The results show that the fatigue life greatly increases as the riser's elastic modulus decreases. In contrast, the fatigue life decreases with an increase of the internal fluid velocity. With an increase of the top tension, the vibration amplitudes and the number of modes may decrease, resulting in fewer bending stress cycles and a longer fatigue life. Furthermore, the structural damping ratio should be as large as possible. Finally, an active and passive control of the riser structure's response to vortex-induced vibration and its fatigue life can be achieved by carefully modifying the parameters mentioned above. The results may provide a theoretical framework for engineering practice concerning the design and control of steel catenary riser structures which are affected by vortex-induced vibration.