基本条件

So it is important to research the spectrum of heat.

土地是人类社会最重要的，也是最基本的自然资源，而热量条件又是制约土地资源利用的一个重要条件，因此对热量带的研究也就显得尤为重要。

It is shown that under the same pay load and range, the power requirements of the ultra-low trajectory and classic minimum energy trajectory are close.

计算和分析表明，在相同载荷条件和射程条件下，超低弹道和经典的最小能量弹道对于火箭动力的需求大致相当，射程10000km以上基本相同。

The paper investigates both block-type pilot linear minimum mean square error algorithm and IEEE802.16 OFDM channel estimation analysis. Simulation results confirm the block-type pilot structure is more suitable for IEEE802.16 system. An optimal pilot setting algorithm, based on space frequency domain, is explored and the pilot chart is presented. The proposed algorithm finds its application in MIMO-OFDM. Simulation results show the algorithm presents a good approximation to the perfect channel state information curve, with about 2dB difference in SNR. The simulation results also demonstrate the algorithm achieves fairly high stability in the environment of fast fading, performance of the proposed algorithm is better that of pilot training channel estimation.3. Taking into account the characteristics of IEEE802.16 OFDM system, OFDM system simulation platform is constructed in Matlab, exploiting simulink as a tool. OFDM modulation and demodulation simulation system are configured on LabVIEW platform. All the system signal processing is simulated, including defining system parameters, designing modulation model, and verifying all the proposed algorithms under different environments, such as white Gaussian noise, multi-path fading, with or without guard interval etc. Bit error performance is evaluated. The research provides valid theoretical basis for practical OFDM system performance evaluation.4. Taking advantage of software radio, the paper designs a hardware platform with both 256-IFFT/FFT and 512-IFFT/FFT OFDM schemes co-existing in one platform. You can predetermine one from the two schemes to carry out almost the same model function with different system performance and parameter setting.5. Referring to IEEE802.16 standard, the paper proposes a design method for generating signals and frames suitable for laboratory investigations implemented in laboratory environment.6. Based on 6701evm digital evaluation card, combined with analogy front-end, the paper designs a DSP software model to deal with baseband signal processing. An overall OFDM scheme, with modulation and demodulation function, is accomplished.

讨论分析了MIMO-OFDM中一种基于空频域的最优导频设置算法，给出了导频图案，通过仿真实验表明，该算法与理想的信道状态信息曲线非常接近，信噪比差距约在2dB左右，并且在快衰落条件下具有较好的稳定性，其性能要优于基于前导训练的信道估计方法。3、根据IEEE802.16OFDM系统特点，论文分别在Matlab中应用Simulink工具构建OFDM系统仿真平台、在LabVIEW平台上实现了OFDM调制解调仿真系统，模拟了整个系统的信号流程，进行了OFDM仿真系统参数的选择和调制模块的仿真设计、论证各算法性能，并根据各种不同的条件：例如高斯噪声、多径衰落、有无保护间隔等，对系统的误码特性进行了评估，为正确评价实际OFDM系统的性能提供了有效的理论依据。4、论文以软件无线电思想作为指导，提出了以256点IFFT／FFT为核心和以512点IFFT／FFT为核心的两种OFDM算法模式并存于同一个硬件平台、且可预选的方案，它们在参数选取和性能指标上有所差异，均实现了相似的模块和功能。5、论文参考IEEE 802.16无线网络标准的参数设置，针对本设计系统的应用环境和系统硬件的性能速率，提出了一种应用于实验室环境的信号结构、帧格式等参数设计。6、论文基于TI公司的6701evm数字评估板卡，结合模拟前端搭建数字中频平台，设计了基带处理的DSP软件模块并进行系统调试，基本实现了一套完整的OFDM调制解调方案。

They deemed that there are some exceptions to the law. The foundation of the law has strict preconditions but all the oppugners neglected it.

边际效用递减规律有严格的前提条件，而众多质疑的例子基本都忽略了其前提条件。

It is conducive to uptake soil nitrogen for flue-tobacco on dryland soil with maize-tobacco rotation before topping (60 days after transplanting) and uptake soil nitrogen for flue-tobacco on paddy soil with rice-tobacco rotation after topping.2 The nitrogen utilization efficiency of rapeseed cake, rice straw and rape straw were 19.5%, 15.5%, 8.1% respectively, and the inorganic fertilizer nitrogen utilization efficiency were 41.1%, 42.7% and 35.7% under the combined application of organic additives and inorganic nitrogen fertilizer. The contribution rate of rapeseed cake, rice straw, rape straw to accumulated nitrogen of flue-cured tobacco were 1.0%, 2.4%, 2.7% respectively by the combined application of organic additives and nitrogen fertilizer. Flue-cured tobacco for organic nitrogen absorption meet with the nitrogen needs laws of high-quality tobacco, indicating that the combined application organic additives and inorganic nitrogen fertilizer reduces the nicotine content of tobacco, an increase of sugar/nicotine ratio and improved the quality of tobacco. In which the role of rice and rape straw is greater than the rapeseed cake can be used as measures to lower nicotine.3 Nitrogen accumulation in flue-cured tobacco with the total nitrogen input was a significant positive correlation during the growth stage of flue-cured tobacco. The total nitrogen input for the 156.3-405.5kg.hm-2, in which the soil nitrogen mineralization capacity account for 22.6%-54.3%, with an average of 34.5%, that is, soil nitrogen mineralization accounted for 1/3 of the total nitrogen input.

旱地轮作土壤有利于烤烟生长前期对土壤氮素的吸收，水旱轮作土壤增加了烤烟生长后期对土壤氮的吸收。2在有机添加物与无机氮肥配施条件下，烤烟对有机添加物中氮的吸收规律基本符合优质烟的需氮规律，其中烤烟对菜籽饼肥、稻草秸秆、油菜秸秆所含氮素的利用率分别为19.5%、15.5%、8.1%，所配施无机氮肥的利用率分别为41.1%、42.7%和35.7%，菜籽饼肥、稻草秸秆、油菜秸秆对烤烟氮素累积量的贡献分别为1.0%、2.4%、2.7%。3不同轮作方式及添加有机物条件下氮素平衡结果显示，烤烟生长期间的氮输入总量为156.3-405.5kg.hm-2，其中矿化氮量为输入总氮量的22.6%-54.3%，平均为34.5%，约为输入总氮量的1/3；肥料氮的利用率为31.4%-42.7%；植烟土壤氮素表观损失率在37.5%-57.2%，平均为46.9%，约为输入总氮量的一半。

The methods of sticking tissues piece to culture primary hFCECs and mouse 3T3 fibroblast conditioned medium to culture passage hFCECs were established;2.The Proliferative capacity of corneal limbus hFCECs is better than central hFCECs.3.3T3 conditioned medium could markedly promote the proliferation of epithelial cells

结论一、组织块贴壁法原代培养人胎儿角膜上皮细胞以及小鼠3T3成纤维细胞条件培养液传代培养方法基本建立；二、人胎儿角膜缘部上皮细胞增殖能力优于中央部；三、3T3细胞条件培养液能促进角膜上皮细胞的增殖。

The conditions for the existence of crank for Watt's mechanism, a basic type of one-degree-of-freedom planar six-bar mechanism,are investigated with the triangular dividing method and the method of instantaneous fixing of the driving bar.

本文采用平面杆机构的三角形划分法及主动杆瞬时凝结法探讨了单自由度平面六杆机构的一种基本型式——Watt型机构的曲柄存在条件；并用取极限的方法得到了其诱导机构的曲柄存在条件。

In addition, the blank holding force that is required to avoid wrinkle and rupture during conical part deep drawing is researched. The necessity of reasonable blank holding force in pressing is expounded. From the view of mechanical analysis, the wrinkle critical condition of side-wall is derived for the first time by the stress state of side-wall, the main deformation region on blank. According to the critical condition of plastic instability for flange, side--wall, corner of punch on blank, The blank holding force in conical part deep drawing is divided into four different regions within its forming figure. The basic principle of reasonable blank holding force during stamping is summarized and provided. The mathematical model of reasonable blank holding force that avoids the wrinkle and rupture is established and verified by the finite element numerical simulation and the grid experiment method. The result shows that it is accurate and reliable.

此外，本文还研究了圆锥形件拉深成形过程中，随着拉深变形过程的进行，毛坯为避免产生起皱、破坏缺陷而对压边力的需求情况，阐明了圆锥形件拉深成形过程中压边力合理变化的必要性；由毛坯主要变形区悬空锥壁部分的受力变形情况，从力学分析的角度，首次推导得出了圆锥形零件悬空锥壁起皱失稳的临界条件；并根据主要变形区法兰、悬空锥壁及凸模圆角部分的塑性失稳临界条件，在其成形范围图中，将圆锥形件成形过程中的压边力划分为四个区域；总结并提出了圆锥形件成形过程中压边力合理变化的基本原则；建立了防止起皱、破坏缺陷产生的压边力合理变化的数学模式，并得到了有限元数值模拟及网格实验法的验证，证实了理论分析结果的正确性和可靠性。

S. G. organs in different places and their personnel were mostly composed of the weak industry-commercial capitalists, who served as the class base of the bourgeoisie constitutionalists and worked in concert with the constitutionalists in political attitudes.

本文以为，清朝末年的地方自治之所以多有困厄，难期顺利发展，主要是因为实行地方自治的各种主客观条件尚不具备，而且实现这些条件又非一朝一夕之功，这无疑也是中国政治近代化发展迟缓、迭遭顿挫的基本原因。

On the basis of above research,various basic functions and interrelations of the system are described in detail.

设计了一个包括用户界面、参数处理、条件形成、维护等在内的查询界面及条件生成系统的总体框架，并以此为基础，详细描述了该系统的各个基本功能及其相互关系。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。