木卫停泊轨道间低耗能小推力转移轨道设计方法研究

对木卫停泊轨道间的低耗能小推力转移轨道设计方法进行了研究,提出基于"类halo轨道截面"法的低耗能转移轨道参数化方法和基于配点法的多体Lambert问题求解算法,并利用全局优化算法得出了燃耗最少的初步优化结果;利用多体同伦法和固定近心点高度的多圈转移控制律得到了各段小推力转移轨道的有效设计结果.所提方法同样适用于其他天体间的转移轨道设计,为多体环境下低耗能小推力转移轨道提出了新的设计思路和方法.

Isolation and Characterization of Photodegradation Impurity in Budesonide Drug Product Using LC-MS and NMR Spectroscopy

Budesonide is a corticosteroid used for the treatment of asthma via various matrices and inhalation mechanisms. An unknown peak of Budesonide aqueous formulation has been investigated during stability study wherein the impurity level observed around 0.1% well below the threshold 0.5%. The approach to identify anonymous species was adopted as first to generate the impurity in sample, isolate, enrich and was subjected to LC-MS/MS and NMR for spectral studies. Based on the spectral data the anonymous species were identified as a “Lumibudesonide’’ ((5aR,5bS,5cS,6S,7aS,7bS,10aR,11aS,11bS)-6-hydroxy-7b-(2-hydroxyacetyl)-5b,7a-dimethyl-9-propyl 1,5a,5b,5c,6,7,7a,7b,10a,11,11a,11b dodecahydrocyclopenta[2'',3'']cyclopropa [1'',2'':3', 4']benzo [1',2':4,5]indeno [1,2-d][1,3]dioxol-5(2H)-one), which is observed in photolysis of Budesonide.

奥曲肽的药效学药动学和治疗学研究

一、提要奥曲肽(Octreotide)为一生长抑素类似物。与内源性生长抑素一样,它对垂体前叶生长激素、促甲状腺激素和胃肠胰腺等内分泌系统肽类的释放都有强力的抑制作用,但与其它外源性生长抑素不同,它没有作用时间短,必需静脉给药及输注后激素反射性分泌增多等缺点。

LDV现在怎么啦?

随着2005年的落幕，伯明翰市最终失去了它的汽车产业。罗孚汽车不得不屈从于不断下降的市场占有率，而且它旗下那些产能不足的工厂经济状况卡死了资金的流动。4个月之后，英国轻型货车制造商LDV（英国莱兰-达夫卡车制造有限公司）这个汽车业的“凤凰”也最终涅磐了。

Identification and Structural Characterization of Secondary Degradant of Arformoterol Impurity in LDPE Respules of Arformoterol Tartrate Inhalation Solution

Arformoterol (R, R) is an enantiomer of racemic formoterol, was the first long-acting beta agonist (LABA), approved by U.S. food and Drug Administration (FDA). The Arformoterol which is used for the treatment of Chronic obstructive pulmonary disease (COPD) are inhaled bronchodilator drugs which are delivered directly to the patient’s airways through a different mechanism. The formulated drug product is kept for stability study as per ICH guideline [1] and during its stability interval analysis by HPLC (High performance liquid chromatography), an unknown peak observed at level around 0.1% which is well below the identification threshold of 0.5% but after heating it crossed the identification threshold. The approach to identify anonymous species of Arformoterol aqueous formulation was adopted as first to generate the impurity in sample, isolate, enrich and Characterize through LC-MS/MS and NMR Spectroscopy. Based on the spectral data the anonymous species was identified as an “Imine impurity”, it is secondary degradant of Amine impurity of Arformoterol formed due to reaction with leachable observed in LDPE respules.

模拟数字转换器输入接口的设计考虑

要针对高速模拟数字转换器（ADC）设计输入接口，是一项富有挑战性的工作，特别是在高频下（〉100 MHz IF）。参考技术手册或是应用笔记的设计是个不错的起始点．但是这种方法会因为新设计的目标会因文件化的设计背离而受到限制。无论是在设计放大器耦合或是变压器耦合的接口，你都必须在许多取舍中做一平衡，以便将看似简单不复杂的电路予以优化。针对这项讨论．我们将会以具有10MSPS或是更高采样率的高速管线ADC的接口来做为考虑。

Mathematical prototypes for collocating geostationary satellites

Collocating geostationary satellites sharing the same position is much demanded for satellite operation recently,the separation strategies are adopted to safeguard the satellites collocated of leaving the relative distance beyond collision with different sets of orbit parameters.This paper presents the mathematical prototypes which establish the allowable relative distance with uncertainty of orbital determination(OD),as well as the orbital element offset for each pair of collocated satellites,and puts forward algorithms to build such relationship to face the challenge of putting three satellites sharing the same position,the algorithms to allocate the longitude,eccentricity and inclination for each satellite are also given to ascertain that the mathematical prototypes are the guide specification to design collocation strategy for geostationary satellites.

Design and optimization of low-energy transfer orbit to Mars with multi-body environment

This paper discusses the problem of design and optimization of low-energy transfer orbit with multi-body environment. A new integrative method is proposed to effectively solve the problem, in which the parameterized patched manifolds in CR3BP(circular restricted three-body problems), the shape-based method with multi-body environment, the homotopic method with multi-body environment, and the low-thrust capturing and descending algorithm with multi-body environment are all included. Firstly, the parameters describing the patched manifolds in CR3 BP are optimized until the least total absolute velocity increment has been got, including the employment of the shape-based method with multi-body environment. Secondly, the low-thrust control laws of the transfer orbit are optimized employing the homotopic method with multi-body environment that transfers the fuel optimization problem to an easier energy optimization problem. Thirdly, the low-thrust descending orbit around Mars is computed using the laws proposed in this paper. As a typical example, the Earth-Mars transfer orbit design is discussed. The results showed that the parameters describing the patched manifolds could be optimized by the DE(differential evolution) algorithm effectively; the homotopic method with multi-body environment could get the optimal value that meets the first order optimality conditions; and the low-thrust descending orbit could effectively be captured by Mars and finally become a circular parking orbit around it by the hypothesis control laws proposed in this paper. It shows that the final fuel cost is much less than the optimal transfer in the patched two-body problems. In conclusion, the method proposed in this paper could effectively solve the low-energy low-thrust optimal control problem in multi-body environment for the future deep space explorations.

Analysis of noncommensurate sampling effects on the performance of PN code tracking loops

Noncoherent early-late processing （NELP） code tracking loops are often implemented using digital hardware for digital global positioning system （GPS） receivers. Noncommensurate sampling technology is widely used because it is viewed as an effective solution to cope with the drawback of digital effects. However, the relationship between the sampling rate and auto-correlation function （ACF） is not adequately characterized by traditional analysis. The principles for selecting the sampling rate are still not apparent. In order to solve this problem, we first analyzed the effects of different sampling rates on ACF and obtained the analytical form of a discrete auto-correlation function （DACF） for a noncommensurate sampling rate. Based on the result, the relationship between the step variation in DACF and NELP parameters such as sampling rate, integration time, and correlator spacing was determined. The maximum step variation size of DACF was also determined. However, considering the actual situation, additional factors such as code Doppler shift, precorrelation filter, and thermal noise may degrade the step variation of DACE The relationship between the step variation and these factors was analyzed separately. An appropriate sampling rate and appropriate correlator spacing were proposed to achieve the typical accuracy of measurement. The numerical simulation verified the validity of the above theoretical analyses, and finally, the conclusions and design constraints for the digital GPS receiver are summarized.

A novel satellite-equipped receiver for autonomous monitoring of GNSS navigation signal quality

Global navigation satellite system(GNSS) comes with potential unavoidable application risks such as the sudden distortion or failure of navigation signals because its satellites are generally operated until failure. In order to solve the problems associated with these risks, receiver autonomous integrity monitoring(RAIM) and ground-based signal quality monitoring stations are widely used. Although these technologies can protect the user from the risks, they are expensive and have limited region coverage. Autonomous monitoring of satellite signal quality is an effective method to eliminate these shortcomings of the RAIM and ground-based signal quality monitoring stations; thus, a new navigation signal quality monitoring receiver which can be equipped on the satellite platform of GNSS is proposed in this paper. Because this satellite-equipped receiver is tightly coupled with navigation payload, the system architecture and its preliminary design procedure are first introduced. In theory, code-tracking loop is able to provide accurate time delay estimation of received signals. However, because of the nonlinear characteristics of the navigation payload, the traditional code-tracking loop introduces errors. To eliminate these errors, the dummy massive parallel correlators(DMPC) technique is proposed. This technique can reconstruct the cross correlation function of a navigation signal with a high code phase resolution. Combining the DMPC and direct radio frequency(RF) sampling technology, the satellite-equipped receiver can calibrate the differential code bias(DCB) accurately. In the meantime, the abnormities and failures of navigation signal can also be monitored. Finally, the accuracy of DCB calibration and the performance of fault monitoring have been verified by practical test data and numerical simulation data, respectively. The results show that the accuracy of DCB calibration is less than 0.1 ns and the novel satellite-equipped receiver can monitor the signal quality effectively.