KE-Rod Initial Velocity of Hollow Cylindrical Charge

KE-rod warhead is a kind of forward interception warhead. To control the KE-rods to disperse uniformly, the hollow cylindrical charge is applied. Initial velocity is crucial to KE-rods distribution and the coordination between the fuze and the warhead. Therefore, based on the classical Gurney formula of cylindrical charge and tabulate interlayer charge, a mathematical model for calculating the KE-rod initial velocity of hollow cylindrical charge has been deduced based on certain assumptions, of which the basis theory is energy and momentum conservation. To validate this deduced equation, high-speed photography and metal-pass target experimental methods were applied simultaneously to test the initial velocity of designed KE-rod warhead. Testing results clearly indicate that the calculated results of the derived mathematical model coincides with the experimental  results, and with the increase in hollow radius, the calculated results become much closer to the experimental results. But the calculated results of classical Gurney formula are far above the experimental results, and the relative error increases with increase in the hollow diameter. The derived mathematical model with satisfactory accuracy is applicable to calculate the KE-rod initial velocity of hollow cylindrical charge in engineering applications.Defence Science Journal, 2011, 61(1), pp.25-29, DOI:http://dx.doi.org/10.14429/dsj.61.7

A 7.4-Bit ENOB 600 MS/s FPGA-Based Online Calibrated Slope ADC without External Components

A slope analog-to-digital converter (ADC) amenable to be fully implemented on a digital field programmable gate array (FPGA) without requiring any external active or passive components is proposed in this paper. The amplitude information, encoded in the transition times of a standard LVDS differential input—driven by the analog input and by the reference slope generated by an FPGA output buffer—is retrieved by an FPGA time-to-digital converter. Along with the ADC, a new online calibration algorithm is developed to mitigate the influence of process, voltage, and temperature variations on its performance. Measurements on an ADC prototype reveal an analog input range from 0.3 V to 1.5 V, a least significant bit (LSB) of 2.6 mV, and an effective number of bits (ENOB) of 7.4-bit at 600 MS/s. The differential nonlinearity (DNL) is in the range between −0.78 and 0.70 LSB, and the integral nonlinearity (INL) is in the range from −0.72 to 0.78 LSB

Cost-effectiveness of policy options for sustainable wetland conservation : a case study of Qixinghe Wetland, China

The study aims to assist policy makers in deciding how best to balance economic development with wetland conservation. Agriculture accounts for more than 75% of the total water use in the Qixinghe Wetlands area. As the flow of water entering the wetlands is diverted, its ecosystem is damaged. This problem affects many wetland areas in China. Research evidence supports recommendations to local government to reconstruct the irrigation system in the area surrounding the Qixinghe Wetlands. These wetlands are the most important breeding ground and migration route for waterfowls in Northeastern Asia

Expression profiles of five FT-like genes and functional analysis of PhFT-1 in a Phalaenopsis hybrid

Background: Phalaenopsis is an important ornamental flowering plant that belongs to the Orchidaceae family and is cultivated worldwide. Phalaenopsis has a long juvenile phase; therefore, it is important to understand the genetic elements regulating the transition from vegetative phase to reproductive phase. In this study, FLOWERING LOCUS T (FT) homologs in Phalaenopsis were cloned, and their effects on flowering were analyzed. Results: A total of five FT-like genes were identified in Phalaenopsis. Phylogenetic and expression analyses of these five FT-like genes indicated that some of these genes might participate in the regulation of flowering. A novel FT-like gene, PhFT-1, distantly related to previously reported FT genes in Arabidopsis and other dicot crops, was also found to be a positive regulator of flowering as heterologous expression of PhFT-1 in Arabidopsis causes an early flowering phenotype. Conclusions: Five FT homologous genes from Phalaenopsis orchid were identified, and PhFT-1 positively regulates flowering

Effects of Extracellular Vesicles from Osteogenic Differentiated Human BMSCs on Osteogenic and Adipogenic Differentiation Capacity of Naïve Human BMSCs

Osteoporosis, or steroid-induced osteonecrosis of the hip, is accompanied by increased bone marrow adipogenesis. Such a disorder of adipogenic/osteogenic differentiation, affecting bone-marrow-derived mesenchymal stem cells (BMSCs), contributes to bone loss during aging. Here, we investigated the effects of extracellular vesicles (EVs) isolated from human (h)BMSCs during different stages of osteogenic differentiation on the osteogenic and adipogenic differentiation capacity of naïve (undifferentiated) hBMSCs. We observed that all EV groups increased viability and proliferation capacity and suppressed the apoptosis of naïve hBMSCs. In particular, EVs derived from hBMSCs at late-stage osteogenic differentiation promoted the osteogenic potential of naïve hBMSCs more effectively than EVs derived from naïve hBMSCs (naïve EVs), as indicated by the increased gene expression of COL1A1 and OPN. In contrast, the adipogenic differentiation capacity of naïve hBMSCs was inhibited by treatment with EVs from osteogenic differentiated hBMSCs. Proteomic analysis revealed that osteogenic EVs and naïve EVs contained distinct protein profiles, with pro-osteogenic and anti-adipogenic proteins encapsulated in osteogenic EVs. We speculate that osteogenic EVs could serve as an intercellular communication system between bone- and bone-marrow adipose tissue, for transporting osteogenic factors and thus favoring pro-osteogenic processes. Our data may support the theory of an endocrine circuit with the skeleton functioning as a ductless gland

Impact of Vehicular Countdown Signals on Driving Psychologies and Behaviors: Taking China as an Example

Countdown signal control is a relatively new control mode that can inform a driver in advance about the remaining time to pass through intersections or the time needed to wait for other drivers and pedestrians. At present, few countries apply vehicular countdown signals. However, in China, some cities have applied vehicular countdown signals for years, though it is unclear how and how much such signals influence driving psychologies and behaviors compared with non-countdown signal controls. The present work aims to clarify the impact of vehicular countdown signals on driving psychologies and behaviors on the cognitive level. A questionnaire survey with 32 questions about driving psychologies and behaviors was designed, and an online survey was conducted. A total of 1051 valid questionnaires were received. The survey data were analyzed, and the main results indicate that most of the surveyed drivers prefer countdown signal controls and think that such controls can improve not only traffic safety but also traffic operational efficiency. The surveyed drivers also think that countdown signal controls have an impact on driving psychologies and behaviors and the survey results have demonstrated that the driving behaviors of female drivers surveyed are not conservative under the clear conditions of green countdown signal control. Further studies and methods concerning the effects of countdown signals on driving psychologies and behaviors are discussed. Document type: Articl