生态安全格局视角下中国城市增长边界研究进展

[目的]新型城镇化不断加快,城市所占土地资源扩张程度越发迅速,传统粗放的城市增长过程中呈现出生态系统结构与功能的破坏、城市无序扩张等问题,怎样合理控制城市规模、优化城市生态安全格局已成为当前中国国土资源管理的重点工作之一.探索中国城市增长边界划定的效益及现行方法,讨论未来发展驱动力和城市增长边界协调优化方法可能的研究方向,为中国城镇可持续发展战略提供理论依据及对未来的增长边界实践提供参考.[方法]通过文献研究法及归纳演绎法,从维护城市生态安全的视角对现行城市空间增长边界进行优化调控研究.[结果]在中国大规模城镇化背景下,实施城市增长管制政策是必然选择,城市增长边界具有多元化的内涵,是城市扩张背景下调控土地资源的重要控制手段,对于提升城市空间治理、保护城市生态安全格局、促进城市可持续发展具有重要意义;中国在城市增长边界划定的技术手段取得一定的成效,学术界从不同的价值取向出发形成了不同的划定技术路径,在划定城市增长边界时,应兼顾城市复杂的属性,深入讨论中国的城市增长规律,结合多样化手段,协调城市边界划定下生态安全格局与城市增长的直接矛盾.[结论]城市增长边界是不同发展背景下限定的城市用地动态扩张边界线,不同时期城市用地扩张界限随经济、社会、自然等影响因素而调整,"弹性"与"刚性"增长边界划定可调控性区域范围及永久性禁止建设的战略性开发空间,秉承生态优先思想,与差别化管控、边界调整、配套措施等协调配合,引导生态安全格局为导向的新型城市增长模式.     

SSLB500型高压电缆铝护套立式双轴连续包覆机的研制

金属护套是交联聚乙烯绝缘高压电缆的重要组成部分,介绍了高压电缆铝护套现有生产工艺及设备的特点;基于四通道连续包覆工艺,开发了SSLB500型高压电缆铝护套立式双轴连续包覆机,检测了挤出铝护套的尺寸和性能,分析了生产数据。研制结果表明:基于数值模拟优化结果设计的工模具结构合理,铝护套成型圆度达到99%,厚度偏差在±5%之内,焊合区域结合强度达到78.8 MPa,延伸率达到33.3%,与非焊合区性能相同;设备长时间运行稳定可靠,主轴转速在6~7.5 r/min时,平均产量达到738 kg/h,平均能耗440 k Wh/t,溢料率小于7%。综合数据表明,所开发的四通道连续包覆工艺及设备具有产品质量好、生产效率高、运行成本低的优点,满足电缆制造企业提质增效的需求。     

Soil Apparent Electrical Conductivity (EC<Subscript>a</Subscript>) as a Means of Monitoring Changesin Soil Inorganic N on Heterogeneous Morainic Soils in SE Norway During Two Growing Seasons

An efficient method to monitor changes in soil inorganic N content during crop growth would be a useful means to guide N fertilization to ensure high yields and low N losses to the environment. In this study, soil apparent electrical conductivity (EC_a) measured by the widely used conductivity meter EM38 was tested as an indirect measurement of available N in spring barley during two cropping seasons at two sites with morainic loam in SE Norway. The experiment was constructed to maximize soil variation. In spite of the ȁ8noiseȁ9 caused by the soil heterogeneity, concentrations of inorganic N (cN_inorg) or NO₃-N were most strongly correlated with EC_a in both years and at both locations (with one exception). The measurements of EC_a reflected well the temporal variation in inorganic N content (N_inorg), and a ranking of the treatments based on EC_a fitted very well with a ranking based on N_inorg at the first three sampling times after fertilizing. The best subset of sensor variables (i.e. variables which can be measured ȁ8on-the-goȁ9 by sensor techniques in the field) described 27–69% (average 47%) of the variation in topsoil cN_inorg. When expanding the regression models to include pH as well, the degree of explanation increased significantly. In conclusion, the method of using EC_a appears to be quite robust in terms of detecting relative differences in cN_inorg, whereas a determination of absolute levels of cN_inorg with the method is unreliable.     

塑料注射机预塑过程爬行现象的产生与控制

根据低速不稳定性的振动机理，对塑料注射机预塑过程中的爬行现象进行分析，推导出注射机液压滑台运行的“液压弹簧”模型。通过建立力学模型和系统的运动微分方程，分析主要影响因素，提出相应措施，达到注射机注射过程低速稳定的目的。     

女性护理液抗炎止痒作用的实验研究

女性护理液为中药苦参醇提液加三氯羟基二苯醚复配而成，根据药理方法学以实验动物建立模型，观察护理液的抗炎、止痒作用。结果，单独使用三氯羟基二苯醚，有较好的抗菌消炎作用，但是止痒作用不明显。以苦参醇提液和三氯羟基二苯醚复配，其抗炎、止痒作用均接近地塞米松磷酸钠注射液。     

一种基于边界特征线且特征点可变的二阶非线性离散跟踪微分器及在测速定位系统中的应用

利用状态反推方法确定最速离散二阶系统的线性区域的边界特征线及控制特征线,以相平面上的点及边界曲线、控制线的相对位置按线性规则确定控制量的大小,区分可达区与线性区,并依此构造最速分段线性函数形式的跟踪微分器（Tracking-differentiator,TD）,这种算法可以方便地修改特征点,适应能力强,而且运算中不包含任何根号运算,使得控制综合函数的形式极大简化,有利于工程实现.对正弦信号及方波信号的仿真结果表明了上述结论的合理性.验证了特征点分段线性算法在适当修改特征点后得到的TD,与经典TD以及它的线性近似进行比较,跟踪能力和微分提取能力都得到了较大的提高.应用移动平均算法构成的跟踪微分器组,具有相位补偿功能,适当选取TD参数后,得到了滤波能力强、相位特性良好的滤波器,并应用于基于长定子齿槽检测的永磁电动磁悬浮列车的测速定位系统中.实验结果表明,本文提出的简化TD按相位补偿确定的方案能有效滤除脉冲和扰动等噪声,对过轨道接缝时的畸变信号进行修复,边界容易修改,算法简单有效,实时性强,易于工程实现.     

Memory E?cient Two-Pass 3D FFT Algorithm for Intelr Xeon PhiTM Coprocessor

Equipped with 512-bit wide SIMD instructions and large numbers of computing cores, the emerging x86-based Intelr Many Integrated Core (MIC) Architecture provides not only high floating-point performanc...     

JSP嵌套SQL Server Reporting Services报表

针对传统物流行业报表的制作、呈现、管理都是由报表业务人员进行操作,不能及时的将报表呈现的数据信息反馈给决策者,导致信息的延误。通过对JSP以及SQL Server Reporting Service（SSRS）的分析介绍,提出把SSRS报表嵌套在JSP中,加入到网络物流系统操作平台。基于SQL Server 2008 R2数据库以及Spring MVC框架,运用Spring注解方式与JSP技术进行系统开发,直接将SSRS报表嵌套在JSP页面供决策者分析。结果表明,JSP页面可以嵌套带有参数要求的SSRS报表,并且可以准确的读取操作SSRS报表,获得满意的嵌套效果。     

Comparative effects of cobalt carboxylates on the thermo‐oxidative degradation of LDPE films

This article reports the effect of three cobalt carboxylates—cobalt stearate (CoSt₃), cobalt palmitate (CoPal₃), and cobalt laurate (CoLau₃)—on the thermo‐oxidative degradation of low‐density polyethylene (LDPE) films prepared by sheeting process. The carboxylates were blended with LDPE in the concentration range of 0.05–0.2% (w/w). The degradation was monitored by techniques such as FTIR spectroscopy, change in the mechanical properties (tensile strength and elongation at break), viscometry, surface electron microscopy, melt flow index measurements, and apparent density measurements. Studies indicate that films containing these additives are highly susceptible to thermo‐oxidative degradation. Oxygen containing functionalities such as carbonyl and vinyl species are generated on the surface of polyethylene because of thermo‐oxidation, as indicated by FTIR studies. This oxidative process is accelerated in the presence of cobalt carboxylates. The degradation of LDPE was found to increase proportionally with concentration as well as with increasing chain length of the cobalt carboxylate, and follow the order CoSt₃ > CoPal₃ > CoLau₃. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3758–3765, 2007