叠层结构对高速板材PCB可靠性影响研究

采用不同类型半固化片设计出多种叠层结构,考察其对高速PCB耐热可靠性的影响,发现扁平玻布(1067、2313等)耐热可靠性较差,无法满足客户无铅焊接要求。同时从理论上分析发现,在耐热可靠性测试过程中,扁平玻布半固化片内应力大和浸胶不完全是引起半固化片分层的主要原因。在生产设计过程中,有耐热可靠性要求的板应禁止或减少扁平玻布半固化片的使用。

地铁盾构叠落段下穿既有建筑物施工技术研究

在城市不断发展和进步的当下,人们对城市交通的便捷要求不断提升。地铁作为一种具备科学性、高效性的城市轨道交通方式,能够有效节约城市空间,为城市的发展与进步打下良好基础保障。但是城市轨道交通在施工的过程中,因为施工工艺非常复杂、施工控制要求较高,导致整个工程的施工风险高、施工难度大。本文以广州市轨道交通十号线工程为例,对地铁盾构叠落段下穿既有建筑物施工技术进行全面研究,并且明确施工当中的技术控制要点,对施工工艺进行进一步分析探索。

纳米叠层金属基复合材料的力学行为

纳米叠层金属基复合材料(nano-laminated metal matrix composites,NLMMCs)由金属和增强材料(陶瓷、非晶以及纳米碳材料)以层状形式交替叠加组成,是构型化金属基复合材料的一种典型代表。由于组分相的纳米尺度、叠层构型以及大量的异质界面,NLMMCs表现出优异的综合力学和功能性能,成为近年来材料科学的研究热点。以金属-陶瓷型、金属-非晶型和金属-纳米碳型NLMMCs为主要对象,重点综述了NLMMCs的常见制备工艺及相应的特点,并聚焦于采用微纳力学方法探究内在和外在特征尺度、叠层取向以及界面特性等对其强韧化和变形机制影响的研究新进展。最后展望了NLMMCs的发展趋势,指出了NLMMCs在特定服役条件下的力学响应机制有待进一步研究,提出了需要开发适用于在多物理场下工作的微纳尺度材料表征和测试系统,以便更精准地探究NLMMCs的使役行为。

运用交互动画探索居住空间中的艺术美

本课题主要针对小空间探索如何运用有限的财力更多拓展实用空间,营造艺术氛围;主要研究如何将交互动画跨界运用于空间设计和家具构造之中,分析和探索其艺术之美。分析和推演了三维数字模型、交互动画构造以及虚拟展示的关键技法,探索了运用交互动画技术发掘家居设计中的艺术之美。采用3D图形软件和游戏引擎,展开对空间造型数据的动态设计和展示。得到数字化的家居展示造型并对其进行美学分析。该方法可为居住空间的数字化设计和交互技术研发提供参考。

A Frequency-Independent Equivalent Circuit for High-k Stacked Monolithic Transformers

A new 2-Π lumped element equivalent circuit model for high-k stacked on-chip transformers is proposed. The model parameters are extracted with high precision, mainly based on analytical methods. The developed model enables fast and accurate time domain transient analysis and noise analysis in RFIC simulation since all elements in the model are fre- quency independent. The validity of the proposed model has been demonstrated by a fabricated monolithic stacked trans- former in TSMC＇s 0.13μm mixed-signal （MS）/RF CMOS＇ process.

高精度阻抗仿真计算与设计过程自动化的实现

随着高频、高速信号对阻抗公差控制要求日益严苛，制前阻抗设计准确度不足成为业界面临的重大技术挑战之一，同时由于阻抗设计过程大多依赖工程经验数据与手工计算使得业界长期遭受阻抗设计准确度差导致良率低、效率低、很难实现自动化等困境。本文将介绍一种适合FR-4玻璃纤维与树脂混合介质层特性的高精度多介质层阻抗模型仿真计算技术，压合后介电常数（Dk/Er）仿真计算技术，以及实现阻抗设计自动化的径途与方法。

基于正交实验的用于LCM的单面挠性印制板翘曲研究

用于LCD显示模块的单面挠性电路板(FPCB)有翘曲度要求。本文以控制翘曲不良为目标,从基材厚度、溢胶量、压合叠构等方面优化工艺参数,研究解决该系列产品翘曲问题的方法。根据正交实验结果可知,影响因素的重要度排序为溢胶量、压合叠构、基材PI厚度,得出最优方案。量产后,该系列产品的合格率得到大幅提升,总体超过98%。本研究也对其它产品的生产起到了借鉴作用。

Contrast of Seismic Reflection Characteristics of Gas Hydrate Distribution between Northeast SCS Slope and Hengchun Ridge

By analyzing and interpreting the newly acquired seismic profile supported by the national 973 Program and synthesizing the data with other geologic ＆ geographic information, we draw conclusions as follows, a） Two seismic reflections located at the northeast South China Sea （SCS） slope and the Hengchun ridge are the Bottom Simulated Reflections （BSRs）. Yet, the genesis and process of the gas hydrate in these two areas are different because of different regional tectonics and geological environments; b） The genesis of gas hydrate located at the northeast SCS slope area is related to the broadly existing fracture zones, slumping tectosomes, and the distinctive shielding environment of pressure masking field formed by them. But the genesis of the gas hydrate at the Hengchun ridge is associated with the thrust nappe structures and accretionary wedges formed along the Manila subduction zone and the related sub-floor fluid channel system built by them; c） Since the analogous geologic bodies are broadly distributed at slope areas around SCS and the temperature-press environment is very suitable to the formation and conservation of the gas hydrate, we suggest that much more of this resource should be stored in these areas.

深入探究内层差分阻抗实测值比设计值偏高之秘

在PCB制造业界进行阻抗控制设计时普遍遇到内层差分阻抗实测值比设计偏高的问题。本文试图通过实验并结合静电场分布理论深入分析PCB玻纤树脂混合介电层对内层差分阻抗模型的影响,并验证业界常用的Polar SI9000阻抗计算软件与实际测量值差异原因。

基于手机USB3.1应用的FPC信号传输研究

5G手机的出现,使得USB3.1的作用尤其突出,基于手机USB3.1应用的FPC产品需要在较高的传输速率下,信号传输需要满足较低的传输损耗。文章主要从叠构设计到过程制作工艺能力管控研究,满足手机USB3.1应用的FPC传输损耗要求。

一款毫米波雷达板板翘改善研究

毫米波雷达板是未来新能源智能汽车ADAS系统的主流配置,文章介绍了一款板翘要求<0.3%的不对称叠构设计毫米波雷达板改善研究。通过研究,得出采用冷热一体压机进行压合、压合后板温下降至60℃以下再下板、拼版设计时减少FR-4侧铺铜面积,这三项措施可明显改善此款产品的板翘不良;内层图形采用LDI固定系数曝光、阻焊后烤改善为斜靠式的隧道炉烤板、采用自动感应板厚的六轴重型磨板线作业等措施对板翘改善也有积极影响。

Laterally Electrostatically Driven Poly 3C-SiC Folded-Beam Resonant Microstructures

Micromachined comb-drive electrostatic resonators with folded-cantilever beams were designed and fabricated. A combination of Rayleigh＇s method and finite-element analysis was used to calculate the resonant frequency drift as we adjusted the device geometry and material parameters. Three micromachined lateral resonant resonators with different beam widths were fabricated. Their resonant frequencies were experimentally measured to be 64.5,147.2, and 255.5kHz, respectively, which are in good agreement with the simulated resonant frequency. It is shown that an improved frequency performance could be obtained on the poly 3C-SiC based device structural material systems with high Young＇s modulus.

Crashworthiness of innovative hexagonal honeycomb-like structures subjected to out-of-plane compression

Seeking for innovative structures with higher mechanical performance is a continuous target in railway vehicle crashworthiness design.In the present study,three types of hexagonal reinforced honeycomb-like structures were developed and analyzed subjected to out-of-plane compression,namely triangular honeycomb(TH),double honeycomb(DH)and full inside honeycomb(FH).Theoretical formulas of average force and specific energy absorption(SEA)were constructed based on the energy minimization principle.To validate,corresponding numerical simulations were carried out by explicit finite element method.Good agreement has been observed between them.The results show that all these honeycomb-like structures maintain the same collapsed stages as conventional honeycomb;cell reinforcement can significantly promote the performance,both in the average force and SEA;full inside honeycomb performs better than the general,triangular and double schemes in average force;meanwhile,its SEA is close to that of double scheme;toroidal surface can dissipate higher plastic energy,so more toroidal surfaces should be considered in design of thin-walled structure.These achievements pave a way for designing high-performance cellular energy absorption devices.

Structural Dynamics of Phenyl Azide in Light-Absorbing Excited States： Resonance Raman and Quantum Mechanical Calculation Study

The excited state structural dynamics of phenyl absorbing S2（A＇）, S3（A＇）, and S6（A＇） states were troseopy and complete active space self-consistent and the UV absorption bands were assigned on azide （PhN3） after excitation to the light studied using the resonance Raman specfield calculations. The vibrational spectra the basis of the Fourier transform （FT）- Raman, FT-infrared measurements, the density-functional theory computations and the normal mode analysis. The A-, B-, and C-bands resonance Raman spectra in cyclohex- ane, acetonitrile, and methanol solvents were, respectively, obtained at 273.9, 252.7, 245.9, 228.7, 223.1, and 208.8 nm excitation wavelengths to probe the corresponding structural dynamics of PhN3. The results indicated that the structural dynamics in the S2 （A＇）, S3（A＇）, and S6（A＇） states were significantly different. The crossing points of the potential energy surfaces, S2S1（1） and S2S1（2）, were predicted to play a key role in the low-lying excited state decay dynamics, in accordance with Kasha＇s rule, and NT=N8 dissociation. Two decay channels initiated from the Franck-Condon region of the S2（A＇） state were predicted： the radiative S2,min→S0 radiative decay and the S2→S1 internal conversion through the crossing points S2S1 （1）/S2S1（2）.

Tensile fracture of as-cast and hot rolled Mg-Zn-Y alloy with long-period stacking phase

An experimental Mg97Zn1Y2(molar fraction,%)alloy was produced by rolling the as-cast alloy.The microstructure of the alloy is composed of theα-Mg(also marked as 2H-Mg with reference to long-period stacking structure according to hexagonal close packed structure)and long-period stacking(LPS)phase.Tensile tests of Mg97Zn1Y2 alloy in comparison with pure Mg were conducted.The fracture morphologies of the tensile specimens were characterized and the microstructures near fracture surface were observed.The results show that the rolled Mg97Zn1Y2 alloy shows a mixed fracture mode including dimples indicating a ductile fracture pattern and a small fraction of cleavage planes indicating a brittle fracture pattern,which is different from the single brittle fracture of the as-cast alloy.In addition,the plastic deformation is mainly from dislocations induced strain with small strengthening effect during plastic deformation in the as-cast Mg97Zn1Y2 alloy,and the strain hardening rate is similar to that of the as-cast pure magnesium.The deformation mechanism of Mg97Zn1Y2 alloy is different from that of the pure magnesium according to a metallographical observation that whether twins are found or not.The strengthening effect hardly exists in the rolled Mg97Zn1Y2 alloy under the same dislocations induced strain,which is different from that of the as-cast alloy with moderate strengthening effect.

Compacton, Peakon, and Foldon Structures in the （2＋1）-DimensionalNizhnik-Novikov-Veselov Equation

By the use of the extended homogenous balance method,the B(?)cklund transformation for a (2+1)- dimensional integrable model,the(2+1)-dimensional Nizhnik-Novikov-Veselov (NNV) equation,is obtained,and then the NNV equation is transformed into three equations of linear,bilinear,and tri-linear forms,respectively.From the above three equations,a rather general variable separation solution of the model is obtained.Three novel class localized structures of the model are founded by the entrance of two variable-separated arbitrary functions.

Development of two rescue robots for disaster relief operations in narrow debris

This paper proposes two novel rescue robots,including a cutter robot and a jack robot,which are aimed to contribute to rescue activities such as to cut through obstacles and to jack up debris in dangerous sites and narrow spaces,where a rescue team can not work or approach.Firstly,a multilinked tracked rescue robot platform composed of connected crawler vehicles is developed,which has high mobility on irregular terrain and ability to move into narrow collapsed structures.Then,the cutter robot and jack robot are designed on the basis of rescue robot platform equipped with a cutter or a jack mechanism and corresponding manipulators in the front segment.The cutter refitted by an angle grinder is able to cut through 10 mm diameter steel bars.The electric jack mechanism designed based on multiple layers screw sleeves structure can lift up 300 kg load from 70 mm to 400 mm.Experimental results validate the capability of the two rescue robots.

A Warming Structure for Piezoelectric Stack Working in Cryogenic Temperature

It is widely acknowledged that the performance of a piezoelectric stack would decline with the temperature decreasing,which will exert negative influence on its application in low-temperature environment.Therefore,a convenient and efficient warming structure for the piezoelectric stack is proposed in this paper to solve this problem.Based on the theoretical analysis of heat transfer,two heating modes,namely,overall heating and local heating are analyzed and compared.Moreover,experimental tests are conducted to evaluate the effectiveness of the structure.Based on the results,it can be concluded that the theoretical results are confirmed with experimental results.Besides,the temperature and performance of the piezoelectric stack are kept stable as temperature varies from 10℃to-70℃,which manifests the feasibility of the structure.Therefore,this paper could be an available reference for those engaged in cryogenic investigation of smart materials and structures.

Flexural behaviour of SFRRAC two-way composite slab with different shapes

To promote the application of green renewable materials in concrete composite slabs(CCSs)and study the flexural behavior of CCSs with different shapes,the bending performances of three CCSs with a SFRRAC base plate,one cast-in-site concrete slab of ordinary concrete and one CCS of ordinary concrete by steel bar truss(as recommended in the technical specification for precast concrete structures in Chinese)were compared through experiments.The carrying capacity,flexural behaviour and bi-directional mechanical properties of the specimens were systematically analyzed from the failure modes,load-deflection curves,load-bar strain curves,load-slip curves and crack distributions.Results show that the bending failure process of CCSs with a SFRRAC base plate is similar to that of the cast-in-site concrete slab of ordinary concrete and CCS of ordinary concrete by steel bar truss,as all of them went through the plastic phase,elastic plastic phase and failure phase with fully developed cracks and deflection.No sudden breakage or horizontal cracking of the connecting interface between the base plate and concrete topping was observed.The shape of the base plate has a major impact on the bearing capacity of the CCS with the SFRRAC base plate.When calculating the ultimate bearing capacity with the plastic yield line theory,the influence of the base plate shape on the plastic yield line position should be taken into account.

Dual influence of the rejuvenation of Southern Tianshan and Western Kunlun orogen on the Cenozoic structure deformation of Tarim Basin,northwestern China:A superposition deformation model from Bachu Uplift

Based on new high-resolution seismic profiles and existing structural and sedimentary results, a superposition deformation model for Cenozoic Bachu Uplift of northwestern Tarim Basin, northwestern China is proposed. The model presents the idea that the Bachu Uplift suffered structure superposition deformation under the dual influences of the Cenozoic uplifting of Southern Tianshan and Western Kunlun orogen, northwestern China. In the end of the Eocene （early Himalayan movement）, Bachu Uplift started to be formed with the uplifting of Western Kunlun, and extended NNW into the interior of Kalpin Uplift. In the end of the Miocene （middle Himalayan movement）, Bachu Uplift suffered not only the NNW structure deformation caused by the Western Kunlun uplifting, but also the NE structure deformation caused by the Southern Tianshan uplifting, and the thrust front fault of Kalpin thrust system related to the Southern Tianshan orogen intrudes southeastward into the hinterland of Bachu Uplift and extends NNE from well Pil to Xiaohaizi reservoir and Gudongshan mountain, which resulted in the strata folded and denuded strongly. In the end of the Pliocene （late Himalayan movement）, the impact of Southern Yianshan orogen decreased because of the stress released with the breakthrough upward of Kalpin fault extending NE, and Bachu Uplift suffered mainly the structure deformation extending NW-NNW caused by the uplifting of Western Kunlun orogen.