Vfp語言易學好用，其排序、檢索速度之快，是VB和DELPHI所不及的，但其保密性差是也大家公認的。只要稍為懂一定數據庫知識的人，一打開數據表，其內容便一目了然，且可任意更改，其保密性和安全性可想而知，這還只是其一。其二：隨著UNFOXpro.exe和Refox7.exe等的出現，你辛辛苦苦編的程序，即使編譯成EXE文件，一經UN或RE則你煞費苦心設置的版權符、驗證關、口令、密碼等都如同虛設。那么Vfp的保密性差的弱點就沒辦法避免嗎？NO ！辦法肯定有，這里就先談談“數據表的加密問題”，以下就是我的一點粗淺看法，請網友們踴躍討論。
標簽： Vfp加密解密
上傳時間： 2020-06-28
上傳用戶：a46213599
This manuscript is a partial draft of a book to be published in early 1994 by AddisonWesley (ISBN 0-201-63337-X). Addison-Wesley has given me permission to make drafts of the book available to the Tcl community to help meet the need for introductory documentation on Tcl and Tk until the book becomes available. Please observe the restrictions set forth in the copyright notice above: you’re welcome to make a copy for yourself or a friend but any sort of large-scale reproduction or reproduction for profit requires advance permission from Addison-Wesley
標簽： Toolkit
上傳時間： 2020-07-05
上傳用戶：
)Armature windings of the electric motor for NO.2 deck cargo winch found low insulation. Windings re-winded,painted and baked dry. (2) NO.1 main air compressor failed to build up pressure.The machine disassembled, cleaned and inspected. The discharge valve plate found broken. The valve palte renewed and running trials tested after being reassembled.
標簽： 答案
上傳時間： 2020-07-14
上傳用戶：
An Arduino core for the ATmega328, ATmega168, ATmega88, ATmega48 and ATmega8, all running a [custom version of Optiboot for increased functionality](#write-to-own-flash). This core requires at least Arduino IDE v1.6.2, where v1.8.5+ is recommended. <br/> **This core gives you two extra IO pins if you're using the internal oscillator!** PB6 and PB7 is mapped to [Arduino pin 20 and 21](#pinout).<br/> If you're into "generic" AVR programming, I'm happy to tell you that all relevant keywords are being highlighted by the IDE through a separate keywords file. Make sure to test the [example files](https://github.com/MCUdude/MiniCore/tree/master/avr/libraries/AVR_examples/examples) (File > Examples > AVR C code examples). Try writing a register name, <i>DDRB</i> for instance, and see for yourself!
標簽： MiniCore
上傳時間： 2021-02-22
上傳用戶：
EMC定義電磁兼容性EMC（ElectroMagneTIcCompaTIbility），在國際電工委員會標準IEC對電磁兼容的定義為：系統或設備在所處的電磁環境中能正常工作，同時不會對其他系統和設備造成干擾。EMC：（ElectromagneTIccompaTIbility）電磁兼容性EMI：（Electromagneticinterference）電磁干擾EMI（ElectroMagneticInterference）：指設備在正常運行過程中對所在環境產生的電磁干擾不能超過一定的限值；EMS：（Electromagneticsusceptibility）電磁敏感度EMS（ElectroMagneticSusceptibility）：指器具對所在環境中存在的電磁干擾具有一定程度的抗擾度，即電磁敏感性。RE：（Radiatedemission）輻射騷擾（EMI）輻射騷擾：主要是指能量以電磁波的形式由源發射到空間，或能量以電磁波形式在空間傳播的現象CE：（Conductedemission）傳導騷擾（EMI）傳導騷擾：傳導干擾是指通過導電介質把一個電網絡上的信號耦合（諧波干擾）到另一個電網絡CS：（Conductedsusceptibility）傳導騷擾抗擾度（EMS）傳導騷擾抗擾度：指抵抗導電介質上干擾的一種能力RS：（Radiatedsusceptibility）射頻電磁場輻射抗擾度（EMS）射頻電磁場輻射抗擾度：指各種裝置、設備或系統，在存在輻射的情況下，抵抗輻射的一種能力ESD：（Electrostaticdischarge）靜電放電（EMS）靜電放電：指具有不同靜電電位的物體互相靠近或直接接觸引起的電荷轉移EFT/B：（Electricalfasttransientburst）電快速瞬變脈沖群（EMS）電快速瞬變脈沖群：指數量有限且清晰可辨的脈沖序列或持續時間有限的振蕩，脈沖群中的單個脈沖有特定的重復周期、電壓幅值，上升時間，脈寬。
上傳時間： 2021-11-07
上傳用戶：
1. Scope ......................................................................................................................................................................... 12. DDR4 SDRAM Package Pinout and Addressing ....................................................................................................... 22.1 DDR4 SDRAM Row for X4,X8 and X16 ................................................................................................................22.2 DDR4 SDRAM Ball Pitch........................................................................................................................................22.3 DDR4 SDRAM Columns for X4,X8 and X16 ..........................................................................................................22.4 DDR4 SDRAM X4/8 Ballout using MO-207......................................................................................................... 22.5 DDR4 SDRAM X16 Ballout using MO-207.............................................................................................................32.6 Pinout Description ..................................................................................................................................................52.7 DDR4 SDRAM Addressing.....................................................................................................................................73. Functional Description ...............................................................................................................................................83.1 Simplified State Diagram ....................................................................................................................................83.2 Basic Functionality..................................................................................................................................................93.3 RESET and Initialization Procedure .....................................................................................................................103.3.1 Power-up Initialization Sequence .............................................................................................................103.3.2 Reset Initialization with Stable Power ......................................................................................................113.4 Register Definition ................................................................................................................................................123.4.1 Programming the mode registers .............................................................................................................123.5 Mode Register ......................................................................................................................................................134. DDR4 SDRAM Command Description and Operation ............................................................................................. 244.1 Command Truth Table ..........................................................................................................................................244.2 CKE Truth Table ...................................................................................................................................................254.3 Burst Length, Type and Order ..............................................................................................................................264.3.1 BL8 Burst order with CRC Enabled .........................................................................................................264.4 DLL-off Mode & DLL on/off Switching procedure ................................................................................................274.4.1 DLL on/off switching procedure ...............................................................................................................274.4.2 DLL “on” to DLL “off” Procedure ..............................................................................................................274.4.3 DLL “off” to DLL “on” Procedure ..............................................................................................................284.5 DLL-off Mode........................................................................................................................................................294.6 Input Clock Frequency Change ............................................................................................................................304.7 Write Leveling.......................................................................................................................................................314.7.1 DRAM setting for write leveling & DRAM termination function in that mode ............................................324.7.2 Procedure Description .............................................................................................................................334.7.3 Write Leveling Mode Exit .........................................................................................................................34
標簽： DDR4
上傳時間： 2022-01-09
上傳用戶：
This Getting Started Guide is written for Maxwell beginners and experienced users who would like to quickly re familiarize themselves with the capabilities of MaxwelL.This guide leads you step-by-step through solving and analyzing the results of a rotational actuator magnetostatic problem with motion By following the steps in this guide, you will learn how to perform the following tasks Modify a models design parameters y Assign variables to a model's design parameters.Specify solution settings for a design Validate a designs setupRun a maxwell simulation v Plot the magnetic flux density vecto v Include motion in the simulation本《入門指南》是為希望快速重新熟悉MaxwelL功能的Maxwell初學者和有經驗的用戶編寫的。本指南將引導您逐步解決和分析旋轉致動器靜運動問題的結果。按照本指南中的步驟，您將學習如何執行以下任務。修改模型設計參數y將變量分配給模型的設計參數。指定設計的解決方案設置驗證設計設置運行maxwell模擬v繪制磁通密度vecto v在模擬中包含運動
上傳時間： 2022-03-10
上傳用戶：
基于PSIM仿真軟件，分析了Boost電路拓撲結構，設定了參數要求進行電路仿真設計，通過電路仿真軟件PSIM對Boost電路工作在CCM模式下，合理設置占空比參數。實驗結果表明理論分析與仿真的一致性和參數設計的正確性，輸出電壓和電流參數穩定，Boost電路輸出效率高。This design is based on PSIM simulation software,analyzes the topology of Boost circuit,sets the parameter re- quirements for circuit simulation design,and reasonably sets the duty cycle parameters for Boost circuit working in CCM mode through PSIM simulation software.The experimental results show that the theoretical analysis and simulation are consis- tent and the parameter design is correct,the output voltage and current parameters are stable.
上傳時間： 2022-05-04
上傳用戶：
文章首先闡述了整個方案的工作原理，給出LDO設計的指標要求；其次，依據系統方案的指標要求和制造1藝約束，實現包含誤差放大器、基準源和保護電路等了模塊在內的電壓調整器：此外，文章還著重探討了“如何利用放大器驅動100pF數量級的大電容負載"的問題；最后，給出整個模塊總體電路的仿真驗證結果。LDO的架構分析和設計以及基準源的設計是本文的核心內容。在LDO架構設計部分，文章基于對三種不同LDO拓撲的分析，選擇并實現了含緩沖器級的LDO./設計中通過改進反饋網絡，采用反饋電容，實現對LDO的環路補償。同時，為提高誤差放大器驅動功率管的能力、適應LDO低功耗發展的需求，文章探討了如何使用放大器驅動大負載電容的問題，基于密勒定理和根軌跡原理，本文通過研究密勒電容的作用，采用MPC（Miller-Path-Compersation）結構，實踐了兩級放大器驅動大負載電容的方案，并把MPC補償技術推廣到三級放大器的設計中。文章設計的CRF（CRF：Current Re ference controlled by Feedback）電流基準是基于對傳統自啟動基準電流源的改進實現的。CRF基準電流源架構中存在一條阻性的電流道路，確保其在加載電源電壓的過程中能夠實現快速啟動，響應速度達到1ps：而傳統自啟動基準電流源在相同的設計參數下，響應速度長達120us.CRF基準電流源突破了響應速度對其應用的限制。
上傳時間： 2022-06-23
上傳用戶：
1、汽車電子類EMC標準要求。全面說明了RE、CE方面的限值要求及測試方法。方便在項目開發前做好評估準備。2、最新版國標。文檔為最新版本說明。節約不必要的時間成本。3、高清PDF文檔。免去各種掃描版無法查找定位的問題。提高可閱讀性及可查找性。4、非加密文檔。非加密文件，可以放心打印。不用反復查找破解軟件，省心省力。5、本標準，對應CISPR:25-2016最新版本。6、下載要求不高。我只需要賺一點點積分，用于下載其他自己需求的標準資料?；ネㄓ袩o
標簽： 無線電
上傳時間： 2022-06-26
上傳用戶：fliang
