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... sôt nấm, rượu nấu ăn NHÓM www.themegallery.com LÒ VI SÓNG Hệ thống rã đông thịt vi sóng Hệ thống thổi phồng vi sóng LÒ VI SÓNG Máy sấy bột vi sóng NHÓM Thank You ! www.themegallery.com LOGO ... NHÓM www.themegallery.com LÒ VI SÓNG Thiết Bị dehydrat hoá và tiêÊt trùng thực phẩm NHÓM LÒ VI SÓNG 3.2 Gia nhiệt và làm khô thịt lượng sóng viba:  Năng lượng vi sóng có thể ứng dụng vào ... gạo NHÓM LÒ VI SÓNG Cấu Tạo: Đ NHÓM www.themegallery.com LÒ VI SÓNG Nguyên Lý Hoạt ĐôỆng:  Sóng viba tạo từ dao động điện từ và khuếch đại nhờ Magnetron hoạt động đèn điện tử cực Năng...

Ngày tải lên: 01/10/2015, 20:32

... vi phơng pháp đun hồi lu xuống vi phút tiến hnh phản ứng lò vi sóng) Ngoi ra, dung môi phản ứng đợc giảm mạnh Trong số trờng hợp, dung môi phản ứng trở nên không cần thiết Do nhiệt độ lò vi sóng ... tổng hợp lò vi sóng (phơng pháp 2) Cho mmol thiosemicacbazit v ml etanol vo bình cầu 100 ml Thêm vo hỗn hợp mmol benzandehit tơng ứng v đến giọt axit axetic băng lm xúc tác Bật lò vi sóng chiếu ... tổng hợp theo phơng pháp đun hồi lu truyền thống v tổng hợp lò vi sóng Các thiosemicacbazon tổng hợp theo phơng pháp sử dụng lò vi sóng có hiệu suất cao hơn, thời gian tổng hợp ngắn phơng pháp...

Ngày tải lên: 28/08/2013, 10:23

... 1.3 Microwave devices Figure 1.4 Solid-state devices used at RF and microwave frequencies TABLE 1.4 Devices Transistors TED IMPATT Selected Applications of Microwave Solid-State Devices Applications ... carry the video information as well Table 1.1 shows the frequency bands used for commercial radio and television broadcasts In the case of digital transmission, a standard monochrome television ... devices because these are easy to manufacture in comparison with circular waveguides However, certain devices (such as rotary joints) require a circular cross-section The ridged waveguide provides...

Ngày tải lên: 15/12/2013, 11:15

... location Two services are available: the standard positioning service (SPS) for civilian use, utilizing a single frequency course=acquisition (C=A) code, and the precise positioning service (PPS) ... and Dt is the directivity of transmitting antenna Power collected by the receiving antenna is Pr ˆ Aer wt …2:4:19† l2 G 4p r …2:4:20† From (2.4.6), Aer ˆ where the receiving antenna gain is Gr ... coef®cients at the terminals of transmitting and receiving antennas are 0.1 and 0.2, respectively Maximum directivities of the transmitting and receiving antennas are 16 dB and 20 dB, respectively...

Ngày tải lên: 15/12/2013, 11:15

... after dividing total voltage by the total current at z ˆ Thus, Zin ˆ V …z ˆ 0† Vin ‡ Vref V ‡V V ‡ Vref ˆ ˆ in ˆ Zo in Vin Vref I …z ˆ 0† Iin ‡ Iref Vin À Vref À Zo Zo or, Vref ‡ Go Vin Zin ˆ ... follows, Vin ˆ vin e jf and Vref ˆ vref e jj the line voltage, in time domain, can be evaluated as follows: v…z; t† ˆ Re‰V …z†e jot Š ˆ Re‰Vin eÀ…a‡jb†z e jot ‡ Vref e‡…a‡jb†z e jot Š or, v…z; t† ˆ vin ... 99:86 V Alternatively, V …z† ˆ Vin eÀjbz ‡ Vref e jbz ˆ Vin …eÀjbz ‡ Ge jbz † where Vin is incident voltage at z ˆ while G is the input re¯ection coef®cient Vin ˆ 50 V€ 0 and, Gˆ 19:21 ‡ j3:52...

Ngày tải lên: 15/12/2013, 11:15

... through the circuit, Ir , Ir ˆ Vin R …4:1:19† Therefore, voltages across the inductor, VL , and the capacitor, Vc , are VL ˆ joo L Vin ˆ jQVin R …4:1:20† and, VC ˆ Vin ˆ ÀjQVin joo C R …4:1:21† Hence, ... determined after replacing s by jo, as follows: Vo … jo† ˆ Vi … jo† Vi … jo†   ˆ joL j ‡ ‡1 1‡ LCo À R joRC RC o or, Vo … jo† ˆ Vi … jo† Vi … jo†  ˆ   j o j o oo À À 1‡ 1‡ RC o2 o oo RC oo ... it will have in®nite Q However, it is not possible in practice In the case of cavity walls having a ®nite conductivity (instead of in®nite for the perfect conductor) but ®lled with a perfect dielectric...

Ngày tải lên: 15/12/2013, 11:15

... on the upper scale of the Smith chart Moving from this point toward the load (that is counterclockwise), open-circuit admittance (zero) is found ®rst Moving further in the same direction, the ... between them This device can be inserted at a convenient point before the load The impedance is matched by adjusting the lengths of the two stubs Of course, it does not provide a universal solution ... The voltage across the load and the attenuation in the matching network are V0 ˆ Vin V R2 RL R kR A ˆ R1 ‡ R2 kRL L Vin R1 R2 ‡ R1 RL ‡ R2 RL …5:3:5† and,  Attenuation in dB ˆ 20 log R2 RL R1 …R2...

Ngày tải lên: 15/12/2013, 11:15

... wn † …6:2:9† where j ˆ À2b` …6:2:10† w ˆ e jj …6:2:11† and, Note that for b` ˆ (i.e., l I ), individual transformer sections in effect have no electrical length and load RL appears to be directly...

Ngày tải lên: 15/12/2013, 11:15

... port-1 is ÀVin eÀ2g` Hence, V1 ˆ Vin À Vin eÀ2g` V2 ˆ I1 ˆ Vin …1 ‡ eÀ2g` † Zo and, I2 ˆ À 2Vin Àg` e Zo Therefore, Y11 Vin  …1 ‡ eÀ2g` †  I1  e‡g` ‡ eÀg` Zo ˆ ˆ ˆ  ˆ À2g` † V1 V2 ˆ0 Vin …1 ... is Vin eÀ2g` Hence, V1 ˆ Vin ‡ Vin eÀ2g` V2 ˆ Vin eÀg` I1 ˆ Vin …1 À e2g` † Zo and, I2 ˆ Therefore, Z11 ˆ  V1  V …1 ‡ eÀ2g` † e‡g` ‡ eÀg` Zo  ˆ Zo coth…g`† ˆ Zo ‡g` ˆ in ˆ  I1 I2 ˆ0 Vin ... respective directions Hence, 3 p Viin Vi ‡ Zoi Ii Vi p  ˆ p ˆ ˆ p p ‡ Zoi Ii 2 2Zoi 2Zoi Zoi …7:6:15† 3 p Viref Vi À Zoi Ii Vi p  bi ˆ p ˆ ˆ p...

Ngày tải lên: 24/12/2013, 17:15

... powerful in the sense that it provides a speci®ed response of the ®lter Both of these techniques are included in this chapter It concludes with a design overview of microwave ®lters 8.1 IMAGE ... and devise some way to control its attenuation around the cutoff Expression for the propagation constant of a T-section is listed in Table 8.1 In order to ®nd g of this T-section, we ®rst divide ... preceding section provides a simple design procedure However, transfer characteristics of this circuit cannot be shaped as desired On the other hand, the insertion loss method provides ways to shape...

Ngày tải lên: 24/12/2013, 17:15

... arrows  Signal Ik traveling along a branch that connects nodes Vi and Ik is multiplied by the branch-gain Zik Dependent node (effect) Vi is equal to the sum of the branch gain times corresponding ... SIGNAL-FLOW GRAPH REPRESENTATION OF A PASSIVE SINGLE-PORT DEVICE Consider load impedance ZL as shown in Figure 9.18 It is a single-port device with port voltage and current VL and IL, respectively ... equation can be rearranged as follows:     Z Z ref in ‡ S VS ˆ ES À À S VS Zo Zo or, ref VS ˆ Dividing it by Zo Z À ZS in E À o V Zo ‡ ZS S Zo ‡ ZS S p 2Zo, we ®nd that ref in VS Zo ES...

Ngày tải lên: 24/12/2013, 17:15

Ngày tải lên: 24/12/2013, 17:15

... CONCEPTS 453 If output impedance of the device is very high then Yo is approximately zero In this case, (11.1.11) can be simpli®ed further For a nontrivial solution, the determinant of its coef®cient ... …11:1:22† Equation (11.1.21) indicates that if X2 is an inductor then X3 is a capacitor or vice versa Further, dividing (11.1.17) by B1 B2 B3, the corresponding reactance relation is found as X1 ‡ X2 ... into (11.1.28), we ®nd that  X À bX2 Vi ˆ Ii X1 ‡ X2 À X X1 ‡ rp  …11:1:31† Impedance Zi across its input terminal can now be determined as follows:   Vi X1 À bX2 …1 ‡ b†X1 X2 ‡ …X1 ‡ X2 †rp...

Ngày tải lên: 24/12/2013, 17:15

... various services such as voice mail, email, video, messaging, data, and computer on-line services The direct link between satellites and personal communication systems can provide voice, video, or ... chapters Chapter reviews some fundamental principles of transmission lines and electromagnetic waves Chapter gives a brief overview of how antennas and antenna arrays work Chapter provides a discussion ... applications in the United States, including televisions, radios, satellite communications, cellular phones, police radar, burglar alarms, and navigation beacons The performance of each application...

Ngày tải lên: 24/12/2013, 17:15

... normalized values Moving away from the load (i.e., toward the generator) corresponds to moving in a clockwise direction A complete revolution around the chart is made by moving a distance l ˆ ... real axis  The Smith chart can be used to ®nd (1) GL from ZL and vice-versa; (2) Zin from  ZL and vice-versa; (3) Z from Y and vice-versa; (4) the VSWR; and (5) dmin and dmax The Smith chart ... À The characteristic impedance of the line is de®ned by  1=2 V‡ VÀ R ‡ joL R ‡ joL ˆ Z0 ˆ ˆ ˆ g G ‡ joC I‡ IÀ …2:28† 20 REVIEW OF WAVES AND TRANSMISSION LINES For a lossless line, R ˆ G ˆ 0,...

Ngày tải lên: 24/12/2013, 17:15

... data The second method is the cavity model [11] This model assumes the rectangular patch to be essentially a closed resonant cavity with magnetic walls The cavity model can predict all properties ... any other antenna, the radiated spherical wave resembles a uniform plane wave in the vicinity of the receiving antenna This can be understood from Fig 3.4 For a large R, the wave can be approximated ... shows the HPBW and SLLs Also shown is FNBW, the first-null beamwidth 3.5.5 Directivity, Gain, and Efficiency The directivity Dmax is defined as the value of the directive gain in the direction of its...

Ngày tải lên: 24/12/2013, 17:15

... solid-state device Figure 4.35 shows a general oscillator circuit, where ZD is the solid-state device impedance and ZC is the circuit impedance looking at the device terminals (driving point) [1] ... regenerative divider The mixer output frequency is   N À1 f f0 À f0 ¼ N N FIGURE 4.42 FIGURE 4.43 Frequency divider Regenerative frequency divider ð4:35Þ PROBLEMS 145 The maximum division ratio ... control devices that provide electronic control of the phase and amplitude of RF=microwave signals The control devices can be built by using ferrites or solid-state devices (p i n diodes or FETs)...

Ngày tải lên: 24/12/2013, 17:15

... sufficient power to pump the mixer The receiver system considerations are listed below Sensitivity Receiver sensitivity quantifies the ability to respond to a weak signal The requirement is the specified ... IEEE.) FIGURE 5.3 Typical dual-conversion receiver 152 RECEIVER SYSTEM PARAMETERS Selectivity Receiver selectivity is the ability to reject unwanted signals on adjacent channel frequencies This specification, ... sensitivity of the receiver In order for a signal to be detected, it should have a strength much greater than the noise floor of the system Noise sources in thermionic and solid-state devices may...

Ngày tải lên: 24/12/2013, 17:15

... lò vi sóng vật liệu suốt sóng vi ba Nó phải cho phép sóng vi ba xuyên qua, làm nóng thực phẩm Thuỷ tinh chịu nhiệt, thuỷ tinh gốm, gốm, gốm đá, sứ số đồ nhựa (theo dẫn nhà sản xuất) sử dụng lò ... Không Không Không Nhựa (dùng cho Đợc lò vi sóng) Đợc Không Không Giấy Không Không Không Đợc Không Không Tấm (dùng sóng) Nấu vi sóng Thời gian ngắn nhựa Đợc lò vi Giấy thiếc Che Không Không Không ... gian ngắn Giấy nhôm phản chiếu lại sóng vi ba nên đợc dùng để che phần không định nấu Thực phẩm chai đóng hộp: Không nên làm nóng thực phẩm chai đóng hộp lò vi sóng trình kéo dài tăng nhiệt Dầu...

Ngày tải lên: 20/01/2014, 07:20

... the reference frequency can also be divided before it is connected to the phase detector This scheme is shown in Fig 6.20 A fixed frequency divider with division ratio of N2 is introduced between ... high-Q circuits to build the oscillators (examples are waveguide cavities, dielectric resonators, or superconducting resonators=cavities); (2) temperature compensation circuits; or (3) phase-locked ... modulation sensitivity in megahertz per volts? Solution Frequency stability ¼ Æ160 MHz=80 C ¼ Æ2 MHz= C ¼ A ðin ppm= CÞ Â 10À6 Â 35 Â 109 Hz A ¼ Æ57 ppm= C Modulation sensitivity ¼ f2 À f1 33:5...

Ngày tải lên: 21/01/2014, 23:20